The usability of rollators as part of the human-centred quality of mobility devices: a systematic narrative literature review

Abstract

Purpose: The aim of this literature review was to identify and summarize aspects of the usability of rollators from the currently available research literature. Further objectives were the exploration of rollator requirements and the search for possible disciplinary differences in the consideration or elaboration of usability aspects.

Materials and Methods: Following the PRISMA guidelines, the databases CINAHL, Pubmed and Academic Search Elite were examined in the period from April – May 2023. For the synthesis of the quantitative and qualitative data and the identification of prominent themes in this work, a theory driven thematic analysis approach was used.

Results: A total of 45 publications were included (25 quantitative, 14 mixed methods, 6 qualitative) from various disciplines, the majority belonging to physiotherapy 42%, followed by engineering 16% and health sciences 16%. Aspects of usability were extracted using a deductive code catalogue based on QUEST 2.0. The categories "easy to use" (28/126), "comfort" (20/126), and "safety" (14/126) were most frequently assigned. While "repairs & servicing" (5/126), "service delivery" (4/126), and "durability" (3/126) were coded least frequently.

Conclusion: So far, no specific publications on the usability of rollators has been published, which made it necessary to summarize individual usability aspects using a deductive code catalogue. The results obtained, therefore, do not allow any generalized statement about the usability of rollators. However, this initiates discussions about the usability of rollators that should be studied in the future in a participatory and user-centred manner and, placing satisfaction more in the focus of usability engineering and evaluation of rollators.

IMPLICATIONS FOR REHABILITATION

• This is the first systematic narrative literature review to comprehensively address and summarize aspects of the usability of rollators and their use.

• The results show that explicit research into the usability of rollators is necessary. To this end, user-centred, participatory research projects should be initiated.

• Developed usability aspects should then also be discussed, classified, and validated in a participatory manner with the end users before they are handed over as requirements to the operationalization of the technological design process.

• When purchasing a rollator, users must insist on product instruction and adaptation. They should also take advantage of rollator training opportunities. Users should also consider that requirements for the rollator can change over time and that the rollator should be checked regularly to ensure that it is in good condition. Relevant guidelines can be found on the internet.

Keywords:

• Rollator
• 4-wheeled walker
• usability
• human-centred quality
• satisfaction
• QUEST

Introduction

According to the definition of the International Organization for Standardization (ISO) rollators are, “…used when a person needs assistance when walking. The rollator can provide stability when walking and standing and reduce the risk of falling. Rollators are designed to support the user inside a frame to carry the user’s weight. Rollators can be equipped with a resting seat, backrest and/or shopping bag. Rollators are not intended to be moved with the user on the seat like a wheelchair. The seat is provided as a resting seat with brakes engaged. …[The rollator is a] walking device, which can be moved by pushing or pulling, that enables a person to maintain stability and balance while walking, that has handgrips… …or a transverse bar and three or more castors/wheels without forearm supports” [1]. In line with prior research [2], different terms such as “wheeled walker”, “rolling walker”, “four-wheeled walker” or “rollator frame” are used for this device, which still makes it very difficult to distinguish the corresponding mobility aids. International review-related literature of the last five years uses the terms rollator [3–7] and walker (wheeled walker or four-wheeled walker) [8–13] about equally often. In this study, we decided to stay with the term “rollator”. We also emphasise that this report is not about walkers without wheels (e.g., with rubber tips) or the version with two wheels [14].

People older than 65 years [15,16], or elderly in general [17], are the main user group of rollators, with a higher number of female users (reported for Denmark in 2000) [2]. This circumstance can be explained by an increase in mobility impairments through physical and functional losses in old age, which become especially noticeable when walking on uneven surfaces, climbing stairs, and/or walking long distances [18]. The overall gender distribution of the over-65s in society is also changing, with the number of older female people increasing [19]. In addition, people with Parkinson’s disease [4,20], Alzheimer’s disease [9,12,21], and chronic obstructive pulmonary disease [3,11,22–27] are frequently mentioned as rollator users. Rollators are also frequently used in the clinical sector as part of early mobilisation after orthopaedic knee or hip surgery [28]. However, the focus of this publication is on the use of rollators in the home or long-term-care setting.

As an artificial part of a socio-technical human-machine system, technical aids, and thus also rollators, have an impact on the respective life situations. They influence individual health, social participation, and quality of life of people with support needs and thus fulfil the desire to remain in their own home environment for as long as possible [29,30]. The International Classification of Functioning, Disability and Health (ICF) of the World Health Organization (WHO) takes this into account by categorising technical aids as environmental factors. According to the WHO definition, “environmental factors make up the physical, social and attitudinal environment in which people live and conduct their lives” [31]. If rollators fulfil the expectations and needs of users in their respective lifeworld, they take on a key position in managing activities of daily living by improving or enabling individual mobility.

Goins et al.’s meta synthesis shows the importance of mobility for elderly people with its subjective aspects and effects in “…mental health, emotional health, social health, and sense of self” [32, p.939]. Changes in individual mobility due to physical and functional loss through ageing or illness have not only physical but also mental and social consequences. The loss of the ability to drive and/or the need to use a mobility aid, like a rollator, changes “…the way an individual is viewed; the way they fit or do not fit into the group; and the individual’s ability to participate in a community” [32,p.939].

Brandt et al. [2] note that “… the rollator proves to be a useful device for people with restricted walking ability…” [2,p.351]. However, the use of rollators often also proves to be problematic, for various reasons [2–4,8,15,33,34]. Inappropriate interactions between people and their rollators can also have significant negative impacts on the individual quality of life of people with support needs and/or on the working conditions of professional and caregiving relatives. Such negative effects can limit mobility and thus social participation and may also contribute to other negative health effects, such as injuries [3,33,34], as described in a study on rollator-associated accidents with the need for emergency room admissions [15]. Such negative effects may indicate improper rollator usage [15] or, alternatively, they could result from non-use. Thus, some elderly people alter their mobility behaviours as reaction to the changed mobility situation. This can include staying at home in bad weather conditions or avoiding activities that require the use of a rollator [32]. Hirsch et al. [35] underline this thesis, “Our research strongly indicates that assuming elders will use an assistive technology simply because they ‘need’ it is misguided. We have seen many examples of elders who downplay this need, choosing to radically alter their behaviours and lifestyles. They will do this even at the expense of independence or social interaction, rather than rely on a device that makes them feel embarrassed or incapable. …We suggest approaching the design of technologies for eldercare in the same way that one approaches the design of other products. This requires the designer to recognize that users have choice, and design products that are not only useful and usable, but also desirable” [35,p.7]. The use of rollators is also dependent on non-material needs, such as training or maintenance. Therefore, rollators should be understood as service-product systems in which the rollator and the associated services are considered inseparable [36]. This circumstance puts the usability of rollators at the centre of focus.

Usability is the “…extent to which a system, product or service can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use” and is therefore central in Human Factors concerning human-machine interactions [37]. Effectivity is built out of the component’s accuracy and completeness, and efficiency out of the factors of time used, human effort, financial resources used, and consumed materials. Satisfaction can be divided into the components of physical reactions, cognitive reactions, and emotional reactions. By adding satisfaction as a part of usability, ISO 9241-11:2018 [38] underlines the importance of user experience as a factor influencing the expected and experienced benefits of a technology [38]. The extent to which efficiency, effectiveness, and satisfaction are most important for usability depends on the respective perspective and the context of use. For example, a user of a rollator could be satisfied with the device and find it effective without being efficient. Alternatively, the rollator could be highly efficient and effective, however the user may nevertheless not be satisfied due to the product design. Satisfaction is the result between product(service) expectations and product(service) accordance and is mostly evaluated from the users’ point of view. While effectiveness and efficiency can be evaluated objectively, the evaluation of satisfaction is usually only possible subjectively [39], e.g., via scales such as The Quebec User Evaluation of Satisfaction with Assistive Technology 2.0 (QUEST 2.0) [40].

The creation of the usability of a product is the task of usability engineering within the respective design and development processes [39]. The increase of usability, or its guarantee, should prevent or reduce use-related damage, such as negative results (e.g., stress, fatigue), non-achievement of goals and tasks, inconvenience or financial damage, or lack of security and privacy. Together with user experience and barrier-free product access (or just accessibility), usability is a component of a human-centred understanding of quality [38]. According to Lavery et al. [41]., “[a] usability problem is an aspect of the system and/or a demand on the user which makes it unpleasant, inefficient, onerous or impossible for the user to achieve their goals in typical usage situations” [41,p.254]. Regardless of the scope and severity of usability problems, they can be both hidden and obvious [39]. For example, a too narrowly designed rollator seat is probably an obvious and therefore easily identifiable usability problem. A sudden failure of the rollator brake due to the combination of certain floor coverings and moisture, on the other hand, is a possible hidden usability problem.

We are convinced that improper rollator usage or non-usage, because of low user acceptance, can be seen as usability problems. Further, we believe that better fitting rollators can be developed based on a comprehensive understanding of the user, context, and tasks resulting in an increase in usability. Based on the above understanding of usability the following research questions arise:

(Q1)How are components of human-centred quality, in particular usability, mentioned, discussed, and presented in the use of rollators?

(Q2)Which product requirements for rollators can be extracted from the literature published to date?

(Q3)How and by which disciplines is the usability of rollators and their components addressed in the scientific literature?

Materials and methods

As we could not find reviews on the usability of rollators in a first literature search, we conducted a systematic narrative literature review. We justify this methodological decision with the necessary synthesis of quantitative and qualitative aspects of usability, its components, and their interpretation. A narrative literature review offers the possibility to include sources of different epistemological origins. [42]. Through a systematic approach, we attempt to counteract the often-described methodological weaknesses of narrative reviews [43]. This should make the literature selection and synthesis as transparent and comprehensible as possible.

Search strategy

Following the PRISMA guidelines [44], the databases CINAHL, Pubmed and Academic Search Elite were searched in April – May 2023. These databases were chosen to overcome the limitations of searching in single databases and to get a wider and deeper selection of publications through interdisciplinary sources e.g., health sciences, design, and engineering. The databases were searched with keywords, combinations, database specific mesh words, and synonyms like: “rollator”, “walking frame”, “walking frame with wheels”, “walker”, “wheeled walker”, “four wheeled walker”, “zimmer frame”, “usability”, “user experience”, “experience”, “serviceability”, “convenience”, “serviceableness”, “ease of use”, “usableness”, “user-friendliness”, “practicality”, “utility”, “usefulness”, “operability”, “practicability”, “use”, “useableness”, and “user friendliness”. The literature search was not delimited by a specific period. Due to limited resources, we did not contact the respective study authors to identify further studies. Further, due to the multidisciplinary spectrum of the included studies, we did not assess the individual studies for risk of bias.

Inclusion and exclusion criteria

Table 1 shows the inclusion criteria. Only literature on exclusively mechanical rollators was included, as these appear to be the predominant type of walker in Germany with a sales volume of 425,227 devices in 2012 [45]. Literature about electronic/smart rollators and/or about add-ons such as activation programmes, integrated "sit-to-stand" support, navigation systems, people tracking etc. was excluded. We also excluded literature on the topic of rollators with fewer than four wheels.

Table 1. Inclusion criteria.

Category	Inclusion criteria
Focus	Only publications addressing the usability or user experience of mechanical rollators or their components (efficiency, effectiveness or satisfaction) or publications describing the human-centred quality aspect with its impact on life activities were included.
Types of publication	Research publication, reviews, user reports, opinion/comment publication, technical reports
General characteristics	Written in English or German Full-text availability 3. Population: adult users

Publication selection

The data sets found were imported into the browser-based literature management programme Rayyan [46], which enables cooperative editing of systematic reviews. In a first step, we removed duplicates of publications, followed by a blind review of titles and summaries regarding inclusion criteria by two of the researchers (MS, AK). Differently rated studies were identified using Rayyan’s traffic light function and finally included or excluded as part of a consensus discussion between both reviewers. A full text analysis of the remaining publications completed this phase, with further relevant texts being added from reference lists.

Data extraction & analysis

In general, narrative literature reviews can be analysed with a distinct number of methodologies [43]. For the synthesis of the quantitative and qualitative data and the identification of prominent themes in this work, we chose the thematic analysis approach. The thematic analysis method has overlaps with narrative summary and content analysis methods, with the possibility to show prominent and recurring themes and their frequency in the literature identified. It “…can be either data driven – driven by the themes identified in the literature itself – or theory driven – oriented to evaluation of particular themes through interrogation of the literature” [42,p.47].

Due to a lack of systematic tool for assessing the usability of rollators and in the context of a human-centred quality perspective, a theory driven approach on satisfaction with rollators was applied, as it plays an important role in predicting the later use and outcomes of assistive technology. This choice allowed for the creation of a deductive coding catalogue based on eight product and four service dimensions (Table 2) of the QUEST 2.0 [40], as they have been proven to classify the objective and subjective aspects of rollator satisfaction [17,47,48]. QUEST functions based on a multidimensional understanding of satisfaction, in which users evaluate individual aspects of technology separately. These evaluations are affected by their “…expectations, perceptions, attitudes, and personal values” [49,p.96]. In this way, not only satisfaction but also effectiveness and efficiency as components of usability [38] and human-centred quality components such as user experience, accessibility, and avoidance of damage through use can be mapped. This approach aims to answer (Q1) and (Q2).

Table 2. Deductive codes based on QUEST 2.0 satisfaction items.

Device dimensions	Definition
Dimensions	Covers the handling of rollators in terms of their product dimensions such as height, width, and length.
Weight	Covers the lifting and moving of rollators in terms of their product weight.
Adjustments	Includes the adjustments of adaptable rollator parts such as handles and the attachment of accessories.
Safety	Covers the extent to which the use of rollators is safe, secure und harmless.
Durability	Describes the robustness and sturdiness of rollators.
Easy to use	Describes how uncomplicated it is to use rollators in practical everyday life.
Comfort	Describes the physical and psychological well-being associated with the use of a rollator.
Effectiveness	Describes how accurately the tasks to be solved are achieved in their goals.
Service dimensions	Definition
Service delivery	Describes how easy it is to purchase the rollator and how long it takes from order to deliver.
Repairs and servicing	Describes how easy it is to repair and service the rollator.
Professional service	Describes the quality of the information provided about rollators, the accessibility and competence of the professionals.
Follow-up service	Describes ongoing support services about rollators, like check-ups etc.

Included publications (Table 3) were transferred into the qualitative data analysis tool MAXQDA 2022 [50] and thematically analysed according to the a priori defined coding catalogue. For this purpose, we coded text passages from the included publications that describe the use of, experiences with, and attitudes towards rollators using the definition of the deductive coding catalogue shown in Table 2.

Table 3. Location, science discipline, design, and target population of included studies.

Reference No.	Study title	Author	Year	Country	Science discipline	Research Paradigm	Study design	Target Population (n)
[2]	Satisfaction with rollators among community-living users: a follow-up study	Brandt et al.	2003	Denmark, Sweden	Neuroscience, Occupational Therapy	mixed methods	Follow-up study using QUEST 1.0. First interview one month after receipt of the rollator. Second interview three months after first interview.	Rollator users First interview: n = 89; Mean age in y (SD): 76.3 (10.4) Second interview: n = 64; Mean age in y (SD) 76.0 (10.7)
[36]	Value-based design for the elderly: An application in the field of mobility aids	Boerema et al.	2017	Netherlands	Electrical Engineering	Qualitative	Design study, in-depth interviews	Participants: n = 10 Wheeled walker users: n = 7 Average age in y: 80.5 (SD = 8.1)
[33]	Walking on the edge: meanings of living in an ageing body and using a walker in everyday life – a phenomenological hermeneutic study	Brännström et al.	2013	Sweden, Finland	Nursing Science	Qualitative	Narrative interviews, analysed with a phenomenological hermeneutic method.	Wheeled walker users: n = 7 Community dwelling persons aged 79–95 y
[6]	Objective measures of rollator user stability and device loading during different walking scenarios	Costamagna et al.	2019	UK, Germany	Health Sciences, Engineering, Geriatric Rehabilitation, Economics	Quantitative	Rollator user stability measurement via an instrumented rollator	Rollator users: n = 10 Average age in y: 84.2 (SD = 5) Patients in Geriatric Rehabilitation Clinic
[20]	Wheeled and standard walkers in Parkinson’s disease patients with gait freezing	Cubo et al.	2003	Spain, USA	Neurological Sciences, Preventive Medicine, Epidemiology	Quantitative	Patients walked three times a standard course (unassisted walking, standard walker, wheeled walker)	Parkinson’s disease patients: n = 19 Mean age in y: 72 (SD = 8)
[7]	Initial results of the evaluation of a digital rollator [Erste Ergebnisse der Evaluation eines digitalen Rollators]	Dupret et al.	2022	Germany	Nursing Sciences, Health Education	Qualitative	Test of an instrumented rollator in everyday life, structured interviews, focus-group interviews, ethnographic observations	Rollator users: n = 10
[64]	A guideline for the design of a four-wheeled walker	Finkel	1997	Canada	Mechanical & Industrial Engineering	Quantitative	Theoretical design study	n/a
[25]	The acute effects of a rollator in individuals with COPD	Gupta et al.	2006	Canada	Rehabilitation Science, Physical Therapy, Medicine	Quantitative	Two 6-min walk tests (unaided + with rollator), at baseline, 4 weeks, and 8 weeks	COPD patients (moderate to severe): n = 31 no previously prescribed walking aid unaided 6 MW of <375 m
[13]	A comparison of muscular activity during gait between walking sticks and a walker in patients with adult degenerative scoliosis	Haddas et al.	2018	USA	Medicine	Quantitative	Over-ground walking at self-selected speed: 1. with walking sticks, 2. with walker, and unaided	Adult degenerative scoliosis patients: n = 20 Mean age in y: 63 (SD = 13.2)
[5]	Gait parameters when walking with or without rollator on different surface characteristics: a pilot study among healthy individuals	Hansson et al.	2022	Sweden	Health Sciences	Quantitative	Experimental, cross-sectional pilot study	Healthy students and university staff: n = 10 aged 23-62 y (median 35 y)
[11]	Effect of using a wheeled walker on physical activity and sedentary time in people with chronic obstructive pulmonary disease: a randomised cross-over trial	Hill et al.	2020	Australia, Singapore, Brazil	Physiotherapy, Respiratory Medicine	Quantitative	Randomised cross-over study, two 5-week phases, 1. with wheeled walker, 2. Unaided Measurement of physical activity and sedentary time + Chonic Respiratory Disease Questionnaire	COPD patients: n = 17 Mean age in y: 73 (SD = 9) no prior wheeled walker prescription (max. 2 weeks) 6MW of <450 m
[22]	Daily utility and satisfaction with rollators among persons with chronic obstructive pulmonary disease	Hill et al.	2008	Canada	Respiratory Medicine, Occupational Therapy	Mixed methods	Cross-sectional observational study using, QUEST 2.0, SGRQ, MRC	Rollator users: n = 27 Mean age in y (SD): 69.9 (9.6) COPD with dyspnoea diagnosis living in the community
[52]	Accessibility for elderly using a four wheeled walker – an interview and observation analysis	Hjalmarson et al.	2013	Sweden	Engineering	Mixed methods	Structured Interviews + Observation of turning with the rollator on a analysing carpet	Rollator users: n = 34 Mean age in y: 90
[3]	Exploring the views of individuals with chronic obstructive pulmonary disease on the use of rollators	Holz et al.	2018	Canada, UK	Physical Therapy; Medicine, Health and Social Care	Qualitative	Semi-structured interviews	Rollator users: n = 12 Mean age 74 y Community dwelling
[27]	Effect of a walking aid on disability, oxygenation, and breathlessness in patients with chronic airflow limitation	Honeyman et al.	1996	Canada	Physiotherapy, Medicine	Quantitative	Two 6-min walk tests (unaided + with wheeled walker)	First time wheeled walker users: n = 11 All users 6-min walking distance less than 300 m.
[12]	Effect of dual-tasking on walking in adults with Alzheimer’s dementia experienced in 4- wheeled walker use	Hunter et al.	2020	Canada, Australia, UK	Physical Therapy, Rehabilitation Medicine, Health Sciences, Biological Sciences, Occupational Therapy	Quantitative	3 walking configurations: 1 straight path, 2. Groningen Meander Walking Test, 3. Figure of 8 path. Tested under 2 walking conditions: 1. single task (walking with aid) + 2. dual task (walking with aid + cognitive task)	Alzheimer dementia patients (mild to moderate): n = 23 Mean age in y: 87.4 (SD = 6.2) at least 6 months of walker use experience.
[59]	The Importance of the 4-Wheeled Walker for Elderly Women Living in their Home Environment - a three-year study	Jonsson	2001	Sweden	Health Sciences, Assistive Technology	Mixed methods	Follow-up study, three interviews and functional tests (1998, 1999 & 2001).	Female rollator users, first session: n = 59 s session: n = 50 third session: n = 30
[17]	Actual use of and satisfaction associated with rollators and “shopping carts” among frail elderly Japanese people using day-service facilities	Kitajima et al.	2017	Japan	Rehabilitation Science	Mixed methods	Cross-sectional study to evaluate the actual use of, and satisfaction with, rollators and shopping carts, QUEST 2.0	Participants: n = 40 Rollator users: n = 20 Mean age in y: 83.2 (SD = 9.6) Shopping cart users: n = 20 Mean age in y: 87.6 (SD = 5.2)
[8]	Housing design that improves the independence and safety for older adults using a walker	Kuboshima & McIntosh	2021	New Zealand	Architectural Engineering, Social Psychology	Qualitative	Ethnographical approach targeting the perceptions and spatial use of adults using walkers	Rollator users: n = 14
[57]	Problems of older persons using a wheeled walker	Lindemann et al.	2016	Germany	Geriatrics, Human Factors, Epidemiology, Automation and Software Engineering	Mixed methods	Cross-sectional experimental study: opening a door against the direction of walking and passing through (with and without wheeled walker) Semi-structured interviews	Wheeled walker users: n = 22 novice users: n = 14 (65%) Median age 82 y Wheeled walker users: n = 60 novice users: n = 29 (48%) long-time users: n = 31 (52%)
[63]	Effect of uphill and downhill walking on walking performance in geriatric patients using a wheeled walker	Lindemann et al.	2017	Germany	Geriatric Rehabilitation, Human Factors, Sports & Movement Science, Automation & Software Engineering	Quantitative	Experimental cross-sectional study. Uphill and downhill course, 1. unaided, 2. with wheeled walker	Geriatric rehabilitation patients: n = 20 Median age in y: 84.5 (75–95) no prior walking aid use
[67]	Assessment of rolling walkers used by older adults in senior-living communities	Liu	2009	USA	Physical Therapy	Mixed methods	Cross-sectional study. Assessment via questionnaires, product inspections and demonstrations	Rolling walker users: n = 158 Mean age in y: 85.4 (65–98) Residents living in retirement centres or assisted-living facilities
[58]	Very old Swedish women’s experiences of mobility devices in everyday occupation: A longitudinal case study	Löfqvist et al.	2009	Sweden, Denmark	Health Sciences, Medicine, Public Health, Assistive Technology	Mixed methods	Exploratory multiple-case study	Rollator users: n = 3 persons aged 86–93 y
[54]	Use of mobility aids reduces attentional demand in challenging walking conditions	Miyasike-daSilva et al.	2013	Canada	Kinesiology, Computer Science, Physical Therapy, Rehabilitation Medicine	Quantitative	Walking 6 min unaided + with four wheeled walkers. 2 different surfaces: 1. level ground and 2. in a wooden beam	Participants: n = 14 12 young subjects (20-39 y) 2 older adults (71 + 72 y) free of gait impairments
[21]	The attentional demands of ambulating with an assistive device in older adults with Alzheimer’s disease	Muir-Hunter & Montero-Odasso	2017	Canada	Physical Therapy, Geriatric Medicine	Quantitative	Walking 6 min + Figure of 8 test with a four wheeled walker. Older adults with Dementia & older adults (control group)	Participants: n = 28 Older adults with dementia: n = 14 Mean age in y: 72.6 (SD = 9.9) Older adults (control group): n = 14 Mean age in y: 72.9 (SD = 9.5)
[4]	Effects of a rollator on fall prevention in Community-Dwelling people with Parkinson’s Disease: A prospective cohort study	Okuyama & Matuo	2023	Japan	Physical Therapy, Sport Sciences	Quantitative	Observational study over 6 months. Number of falls and injuries. Two cohorts: PD patients with rollator use, PD patients without rollator	Participants with PD Mean age in y: 69.9 (SD = 6.1) Rollator users: n = 14 Without rollator: n = 16
[9]	The effects on gait of 4-wheeled walker use in people with Alzheimer’s disease, dementia and gait impairment: a pilot study	Omaña et al.	2022	Canada	Health Sciences, Physical Therapy	Quantitative	Walking 6 min + Figure of 8 test 1. unaided, 2. with a four wheeled walker, 3. with a four wheeled walker while counting backwards	Older adults with dementia: n = 11 Median age in y: 91 (84–92) currently using a four wheeled walker
[10]	The effect of first-time 4-wheeled walker use on the gait of younger and older adults	Omaña et al.	2022	Canada, England, Australia	Health Sciences, Physical Therapy; Biological Sciences, Rehabilitation medicine, Optometry, Occupational Therapy	Quantitative	Cross-sectional study, walking 6 min + Figure of 8 test 1. unaided, 2. with a four wheeled walker, 3. with a four wheeled walker + cognitive task	Younger adults: n = 25 Median age in y: 26 (23.0–30.5) Older adults: n = 24 Median age in y: 68 (59.3–76.5)
[65]	Predictors of falls in elderly people during rehabilitation after hip fracture – who is at risk of a second one?	Pils et al.	2003	Austria, Netherlands	Rehabilitation Medicine, Medical computer sciences, Geriatric Medicine	Quantitative	Consecutive prospective study	Rehabilitation patients: n = 935 Rollator users: n = 639
[61]	Designing devices that are acceptable to the frail elderly: a new understanding based upon how older people perceive a walker	Pippin & Femie	1997	Australia, Canada	n/a	Qualitative	semi-structured interviews and focus groups, social phenomenological approach	Rollator users: n = 22 Mean age in y (range): 81 (63–94)
[26]	Mechanisms of improvement in exercise capacity using a rollator in patients with COPD	Probst et al.	2004	Belgium, Brazil	Respiratory Medicine, Rehabilitation Sciences, Physical Therapy	Quantitative	Walking 6 min with a portable metabolic system, unaided and with rollator	COPD patients (mild to very severe): n = 14 Median age in y: 70 (65–76) no prior use of walking aides
[51]	Consumer survey into complaints about rollators	Raijmakers	2001	Netherlands	n/a	Mixed methods	Consumer survey, telephone questionnaire	Participants: n = 412 Rollator users (%): 78.4 Average age: 77.7 y
[48]	User satisfaction with mobility assistive devices: An important element in the rehabilitation process	Samuelsson & Wressle	2008	Sweden	Rehabilitation Medicine, Geriatrics	Mixed methods	Cross-sectional follow-up study using QUEST 2.0, additional questionnaire (sent via postal service)	Participants: n = 262 Rollator users: n = 175 wheelchair users: n = 87
[62]	Instrumented gait analysis: a measure of gait improvement by a wheeled walker in hospitalized geriatric patients	Schülein et al.	2017	Germany	Geriatric Medicine, Molecular Neurology, Computer Science, Psychogerontology	Quantitative	Walking an instrumented walkway with wheeled walker and unaided. Participants equipped with inertial sensor (shoes)	Patients: n = 106 Mean age in y: 81.7 (SD = 6.2) gait and balance impairments experienced and inexperienced wheeled walker users
[68]	Theoretical optimization of usage of four-wheeled walker and body posture of elderly users for comfortable steady walking	Takanokura	2008	Japan	Engineering	Quantitative	Theoretical study of usability interaction with individual exercise capabilities	n/a
[69]	Optimal handgrip height of four-wheeled walker on various road conditions to reduce muscular load for elderly users with steady walking	Takanokura	2010	Japan	Engineering	Quantitative	Theoretical study about the handgrip height of four wheeled walker from a biomechanical viewpoint	n/a
[34]	The impact and use of walkers among older adults: a pilot	Thomas et al.	2008	Canada	Physiotherapy	Mixed methods	Sequential explanatory design (3 vists – Quantitative, quantitative, qualitative) (BBS, TUG, 6MWT, ABC, LIFE-H) and narrative interviews	Wheeled walker users: n = 4 persons aged 78–86 y Long-term care: n = 1 Retirement home: n = 2 Own house: n = 1
[23]	The effects of a "new" walking aid on exercise performance in patients with COPD: a randomized crossover trial	Vaes et al.	2012	Netherlands	Physiotherapy, Occupational Therapy; Human Movement, Nutrition, Toxicology and Metabolism Science; Respiratory Medicine	Quantitative	Randomized Crossover Trial. Walking 6 min with a modern draisine and a rollator + questionnaire	COPD patients: n = 21 Mean age in y: 64.2 (SD = 10.1) Rollator users: n = 8
[24]	Efficacy of walking aids on self-paced outdoor walking in individuals with COPD: a randomized cross-over trial	Vaes et al.	2015	Netherlands	Physiotherapy, Occupational Therapy; Human Movement, Nutrition, Toxicology and Metabolism Science; Respiratory Medicine	Quantitative	Randomized Crossover Trial. Performing three self-paced outdoor walking tests. 1. unaided. 2 + 3 with a modern draisine or a rollator + questionnaire	COPD patients (moderate to very severe): n = 15 Mean age in y: 63.3 (SD = 8.2) no prior use of walking aids
[66]	Rollator use and functional outcome of geriatric rehabilitation	Vogt et al.	2010	Germany	Sports Medicine, Geriatric Medicine	Quantitative	Quasi-experimental pre- and post-design. Timed "Up-and-Go" test, "Five-Times-Sit-to-Stand" Test and "Performance-Oriented Mobility Assessment-Balance Test with 3 patient groups. 1. First time users, long-term users, and control	Geriatric rehabilitation patients: n = 90 First time rollator users: n = 30 Long-term rollator users: n = 30 Control group: n = 30
[53]	understanding the lived experience of five individuals with mobility aids	Walsh & Petrie	2016	UK	Computer Science	Qualitative	Semi-structured interviews	Participants: n = 5 Wheeled Walker users: n = 2 wheelchair/prostheses: n = 3
[55]	Changes in dual-task voice reaction time among elders who use assistive devices	Wellmon et al.	2006	USA	Physical Therapy	Quantitative	Measuring of the voice reaction time while walking and standing with 1. rolling walker 2. straight cane or 3. unaided	Participants: n = 105 Rolling walker: n = 35 Mean age in y: 87,8 (SD = 5.5) Straight cane: n = 35 Mean age in y: 84,1 (SD = 5.6) Unaided: n = 38 Mean age in y: 79,9 (SD = 4.5) All living in a retirement community
[60]	Barrier-free outdoor environments: older peoples’ perceptions before and after implementation of legislative directives	Wennberg et al.	2010	Sweden	Technology & Society	Mixed methods	Before-after study of an implementation “Removal of physical barriers in the outdoor environment”. Focus groups interviews, participant observations and questionnaires.	Before-questionnaire: n = 356 After-questionnaire: n = 244 Focus groups: n = 10 Observations: n = 3
[47]	User satisfaction with mobility assistive devices	Wressle & Samuelsson	2004	Sweden	Occupational Therapy, Rehabilitation Medicine	Mixed methods	Cross-sectional descriptive study, questionnaire + QUEST 2.0 (sent via postal service)	Participants: n = 209 Walker users: n = 135 Mean age in y (range): 71 (38–82)
[56]	The dual-task methodology and assessing the attentional demands of ambulation with walking devices	Wright & Kemp	1992	USA	Physical Therapy	Quantitative	Experimental study. Three phases, 1. performing reaction time task, 2. performing each of the walking tasks, 3. dual task (reaction time task + walking tasks). Two Groups: 1. Informed about device, 2. Uninformed about device	Participants: n = 10 Mean age in y: 30,8 (SD = 8.1) no prior use of walking aids

With the aim of answering (Q3), we generated a data matrix to extract the following structural data of the publications: year of publication, type of publication, country, discipline, and research methodology.

Results

Publication selection process

Figure 1 provides a flow chart presenting the selection process. Among the initial identified 779 publications, we found 96 duplicates and removed them using Rayyan’s automatic duplicate detection. In a second step, the titles, and abstracts of 683 publications were blindly screened by two reviewers according to inclusion criteria, resulting in the exclusion of 542 publications due to non-suitable subject matter. Furthermore, no abstract could be found for 6 publications. In a next step, we analysed the remaining 135 full-text publications according to inclusion criteria, which resulted in the exclusion of 93 publications because they either did not deal with the four-wheeled version of the rollator (n = 39), exclusively addressed robotic or "smart" rollators or add-ons (n = 24), or did not deal with usability or its components (n = 30). In addition, 3 thematically relevant publications were identified from the reference lists of the included publications and added, leading to a total of 45 publications for review. Table 3 provides an overview of the included publications.

Figure 1. PRISMA flow chart of selection process.

PRISMA FLOW chart depicting the selection process of articles. The process includes identification (CINAHL n = 347; Pubmed n = 356; Academic Search Elite n = 76), screening (n = 683), and inclusion (n = 45) of found articles. A total of 548 articles were excluded based on title and abstract screening, and 93 articles were excluded against the inclusion criteria.

Characteristics of the included publications

Figure 2 shows the countries of origin of the 45 included publications and their frequency. For reasons of feasibility, multinational research projects were assigned to the nationality of the leading author. From a continental perspective, Europe (51.1%) leads the included list of publications, followed by North America (33.3%), Asia (8.9%) and Australasia (6.7%).

Figure 2. Country-specific distribution.

World map showing the country-specific distribution of articles included in the review. The table below lists the countries with frequencies and percentages: Canada (11, 24.4%), Sweden (9, 20%), Germany (5, 11.1%), and others.

Table 4 shows the various methodological approaches of the included publications and disciplines. Quantitative studies (56%) are the leading methodological approaches, followed by mixed methods (31%) and qualitative (13%) study designs with a varying frequency in the respective disciplines. Due to the variety of differently named disciplines, we grouped some professions under umbrella terms where possible:

Table 4. Disciplinary & methodological distribution.

Discipline	Engineering	Geriatric Medicine	Health Science	Physiotherapy	Neurological Science	Nursing Science	Respiratory Medicine	Unknown
Quantitative (Freq.)*	3	2	4	13	2	–	1	–
Qualitative (Freq.)*	2	1	–	1	–	2	–	–
Mixed methods (Freq.)*	2	1	3	5	1	–	1	1
Total publications	7	4	7	19	3	2	2	1
Percentage of included publications (%)	16%	9%	16%	42%	7%	4%	4%	2%

* Frequency in the specific discipline.

• Engineering: also, computer science, design, architecture, technology science

• Physiotherapy: also, rehabilitation science, physical therapy, kinesiology, occupational therapy, sports medicine.

One publication was classified as “unknown” as it was unclear which discipline it belonged to. For reasons of feasibility, we assigned multidisciplinary research projects to the discipline of the leading author. As shown in Table 5, the publications included are both monodisciplinary and multidisciplinary. Here, 4 publications stem from the 1990s, 16 publications from the 2000s years, 17 publications from the 2010s years and 8 publications from the current decade.

Table 5. Mono/Multidisciplinary distribution & publications by year.

Mono/Multidisciplinary
Discipline		Freq.	%	Discipline		Freq.	%
Engineering	Monodis.	6	86	Neurological Science	Monodis.	1	33
	Multidis.	1	14		Multidis.	2	67
	Total	7	100		Total	3	100
Geriatric Medicine	Monodis.	1	25	Nursing Science	Monodis.	1	50
	Multidis.	3	75		Multidis.	1	50
	Total	4	100		Total	2	100
Health Science	Monodis.	1	14	Respiratory Medicine	Multidis.	2	100
	Multidis.	6	86
	Total	7	100
Physiotherapy	Monodis.	5	26	Unknown	Monodis.	1	100
	Multidis.	14	74
	Total	19	100

Code frequency in the data set

Figure 3 shows the mention of the respective codes of the dimension device and service satisfaction in the included publications. Table 6 shows the absolute frequencies of the codes assigned for each publication included.

Figure 3. Code frequency based on device and service satisfaction items.

Treemap chart showing the frequency of codes given in the included literature based on device and service satisfaction items from QUEST 2.0. "Easy to use" is the largest category with 28 codes, followed by "Comfort" with 20 codes, and "Safety" with 14 codes. Other categories include "Effectiveness" (11), "Dimensions" (10), "Professional services" (9), "Adjustments" (8), "Weight" (8), "Follow-up services" (6), "Repairs & servicing" (5), "Service delivery" (4), and "Durability" (3).

Table 6. Absolute frequencies of the codes assigned for each publication.

		Code frequency device dimensions								Service dimensions
Reference No.	Publications	Di*	W*	Adj*	Saf*	Dura*	Eas*	Com*	Eff*	SD*	RS*	PS*	FS*
[36]	Boerema et al.						2
[2]	Brandt et al.	2	1	1			3	2	1			2	1
[33]	Brännström et al.	2			2		13
[6]	Costamagna et al.							1
[20]	Cubo et al.							1
[7]	Dupret et al.						6
[64]	Finkel							1
[25]	Gupta et al.								2
[13]	Haddas et al.							1
[5]	Hansson et al.							1
[11]	Hill et al.								1
[22]	Hill et al.	1	1		2		5	2	3
[52]	Hjalmarson et al.						3
[3]	Holz et al.		1		1		8		1			4
[27]	Honeyman et al.								1
[12]	Hunter et al.						3
[59]	Jonsson	2	1	1	2		2	1
[17]	Kitajima et al.	1	1	1	1	1	1	1	1	1	2	2	1
[8]	Kuboshima & McIntosh				1		8	2
[57]	Lindemann et al.				1		6	2
[63]	Lindemann et al.							2
[67]	Liu			1							1	2
[58]	Löfqvist et al.	2			1		5	2
[54]	Miyasike-daSilva et al.						2
[21]	Muir-Hunter & Montero-Odasso						2
[4]	Okuyama & Matuo				3		2
[9]	Omaña et al.						2	1
[10]	Omaña et al.						1
[65]	Pils et al.				1
[61]	Pippin & Femie						3
[26]	Probst et al.								1			1
[51]	Raijmakers	1	1				1	1		1	1	2	1
[48]	Samuelsson & Wressle	1	1	1	2	1	4	2	2	1	1	2	2
[62]	Schülein et al.							1
[68]	Takanokura			1
[69]	Takanokura			1
[34]	Thomas et al.	2			3		5	1
[23]	Vaes et al.						1
[24]	Vaes et al.								1
[66]	Vogt et al.				1
[53]	Walsh & Petrie						4	1				2	1
[55]	Wellmon et al.						2
[60]	Wennberg et al.						2
[47]	Wressle & Samuelsson	1	1	1	1	1	2	1	1	1	1	1	1
[56]	Wright & Kemp						1
	Total:	15	8	8	22	3	99	27	15	4	6	18	7

Di*: dimension; W*: weight, Adj*: adjustments; Saf*: safety; Dura*: durability; Eas*: easy to use; Com*: comfort; Eff*: efficiency; SD*: service delivery; RS*: repairs & servicing; PS*: professional services, FS*: follow-up services.

The detailed results of the codes assigned are presented in detail below, in order from the most frequent to the less frequent. Introducing the results, we present statements about the general rollator satisfaction and three studies using the QUEST 2.0.

General rollator satisfaction & QUEST 2.0 assessment

The reported overall user rollator satisfaction was high [2,3,36,47,48,51], with a resulting high frequency of use [2]. Samuelsson & Wressle [48] described the individual impacts of rollators compared to wheelchairs as more positive in terms of the user’s sense of mobility, independence, self-esteem, and safety with a strong impact on everyday life. Raijmakers [51] reported in this regard of elderly users who were “…full of praise for rollators in general. However, paradoxically they were less enthusiastic about their own rollators” [51,p.200]. Brandt et al. [2] identified the female gender and people living alone as indicators of a higher likelihood of rollator dissatisfaction.

Three studies were found that assessed the satisfaction with rollators via the QUEST 2.0 instrument, see Table 7.

Table 7. Rollator satisfaction via QUEST 2.0.

	QUEST 2.0 items	Kitajima et al. (2017) (n = 20)		Samuelsson & Wressle (2008)			Wressle & Samuelsson (2004) (n = 135)
		“% Subjects” (4–5)	“% subjects” (1–3)	“% Subjects” (4–5)	“% Subjects” (1–3)	(n)	Mean values (SD)
Device subscale	Dimensions	70	30	92	8	139	4.52 (0.66)
	Weight	65	35	80	20	117	4.18 (0.98)
	Adjustment	67	33	87	13	130	4.13 (0.99)
	Safety	70	30	92	8	139	4.56 (0.73)
	Durability	90	10	90	10	133	4.49 (0.73)
	Ease of use	70	30	94	6	140	4.55 (0.81)
	Comfort	70	30	90	10	137	4.35 (0.82)
	Effectiveness	90	10	95	5	139	4.57 (0.76)
Service subscale
	Service delivery	90	10	80	20	107	4.31 (1.12)
	Repairs & services	65	35	71	29	78	3.77 (1.40)
	Professional service	65	35	76	24	99	4.08 (1.29)
	Follow-up service	55	45	63	37	86	3.54 (1.48)

1 “not satisfied at all”; 2 “not very satisfied”; 3 “more or less satisfied”; 4 “quite satisfied; 5 “very satisfied” [40].

Dimension: device satisfaction

Ease of use

User reported on rollator experiences as “…being forced to learn new skills to use a walking aid” [33,p.118] and difficulties in finding creative solutions and strategies to challenge physical usage barriers like walking through narrow or heavy doors [3,52]. But in general, the using of rollators was rated as easy [2,22,48,53]. Miyasike-daSilva et al. [54] pointed out that walking with a rollator under difficult surface conditions that affect balance, such as the test conducted in the study where participants walked on a 5cmx5cm narrow wooden beam, can reduce attentional load and increase gait stability in healthy people without mobility impairments [54]. For cognitively impaired people, however, walking with a rollator can be a complex task, with different motor and cognitive requirement [9,12,55,56], with the possible result that there may be fewer advantages to a rollator for Alzheimer’s patients in the cases involving a dual tasks (such as walking and talking) [9]. Even in experienced walker users with Alzheimer Disease, the gait parameters and gait stability changed in difficult usage environments with additional cognitive tasks [12], according to Omaña et al. [10] with “…prioritization of gait over the cognitive task” [10,p.4]. Muir-Hunter & Montero-Odasso [21] underlined this hypothesis, noting “[a]mbulation with a 4-wheeled walker, in particular maneuvering around obstacles, requires greater attentional costs in dementia” [21,p.202]. Okuyama & Matuo [4] pointed out that people with impaired psychophysiological functioning may also have problems using rollators. People with Parkinson’s disease are therefore easily distracted by environmental influences and hence have difficulty concentrating on using the rollator [4]. As a result, an increase in attention costs can lead to an increase in the risk of falls [12,21,55].

The found literature identified various requirements for the usage context of rollators [33,57], which is built out of the physical and social environments [34]. In this regard, obstacle crossing (indoor and outdoor) is often a fundamental usage problem [57]. First, there is a need to get in and out of the people’s houses or apartments [7,33,57]. Stairs and steep ramps are frequent usage barriers [7,22,34,52,53,57,58]. For this reason, users need a ground floor dwelling or an elevator. Otherwise, they have to use a stair lift or use the stairs unaided with a higher risk of falling [33]. In this regard, users reported in two surveys that they take the stairs daily without assistance and have to leave their walkers in the hallway [7,59]. Users also described carpets, narrow spaces, and heavy and/or hinged doors as additional indoor obstacles beside stairs [3,8,52,57,58]. Driving over floor coverings with different heights was considered a safety risk. Even with small height differences of 1 cm, where the rollator does not have to be lifted, there is a risk of spillage when transporting hot drinks or meals [8]. Passing through hinged doors is difficult while using a rollator, as users must reach over the rollator to grab the door handle. In addition, rollator users must use different door opening strategies depending on whether the door swings inwards or outwards. If the door swings inwards, the door and the rollator must be pulled backwards at the same time, whereas if the door swings outwards, the rollator and the door must be pushed forward at the same time [8,57]. In the study by Kuboshima & McIntosh [8], one participant reported that because of his walker, the door cannot be closed completely due to the small space between the toilet and the door. As a result, the door remains slightly open when the user goes to the toilet, even during a guest visit [8].

In general, rooms that are too small make it difficult or impossible to use rollators. Manoeuvres such as turning around are so difficult that users often bump into walls or objects in the room. Therefore, if the room space is too narrow, rollators have to be left in front of the kitchen/bathroom, for example [8]. Because of these indoor usage barriers, users used canes, furniture, walls [3,8,58,59], hand basins, towel rails, and handrails [8] as mobility support instead of rollators. This in turn often results in an increase of falls [8,58].

In Wressle & Samuelsson’s [47] survey, 47% of the usage environment was “Outdoors”, 39% used “In-and outdoors”, and 9% only “Indoors”. They majority used rollators “All year” (84%), while 4% used the rollator only in winter and 2% only in summer [47]. In relation to outdoor use, rollator users are very dependent on walkways [7,33,51,60] being in good condition. Beside year-round obstacles like gravel, potholes, or curbs, seasons like autumn or winter can be very dangerous because of snow, ice, and wet leaves on the ground [7,33,60]. Therefore, users reported that they sometimes must switch to the street, exposing themselves to a higher risk of accidents. Poor visibility due to poorly lit sections of road and short traffic light phases were mentioned as further problems [7]. How, when, and how often rollators are used indoors and outdoors can differ. In the study by Hill et al. [22] the COPD patients surveyed used their rollators for walking outdoors, while the majority did not need support from indoor rollators [22].

Using a rollator is in the most cases not a matter of choice or a convenience decision. Instead, the rollator can be a daily reminder of the individual dependency of a mobility device and therefore an absolute must to stay mobile [33]. Due to this partial individual high device dependency, users reported anxiety when their rollator was not nearby [33,34,58]. Furthermore, users expressed the need of transforming the self-image to use a rollator [33,34,61]. According to user statements, rollators can be an unwanted sign of senior age and handicaps; as such they are potentially shameful for some users [2–4,22,23,33,34,36], with users sometimes experiencing negative effects like starring of their surroundings or encounters with rude people [53]. But according to Brandt et al. [2], most of the users were satisfied with the reactions of their social surrounding [2].

Nevertheless, it can be hard work for users to accept their own changed appearance and the possibly resulting perception of others [33], with possible negative life effects, such as falls or loneliness, due to shrinking mobility if rollators are rejected out such shame [3,33,34]. In addition, Holz et al. [3] showed possible differences in the acceptance or rejection of rollators depending on the individually perceived duration of use. The refusal to use a rollator was lower when the perceived duration of use was transient [3]. Hill et al. [22] pointed out “…other peoples’ reaction has also been identified as an indicator of dissatisfaction with rollators in elderly patients” [22,p.1111]. In this regard, participants from the Boerema et al. [36] study felt that an appealing design of mobility aids can reduce possibly associated stigmata [36]. In this context, a user from the study by Walsh & Petrie [53] reported that she was not ashamed of her rollator purchased online because it was light and inconspicuous. She also did not feel that she was viewed negatively by those around her because of her rollator [53].

Users reported that after they were able to accept their rollators, the positive aspects of the devices outweighed the negative ones, and they were again able to perform their individual activities of daily living in a somewhat self-determined way, which led to an active social participation [3,33,48,61] and an increase of individual self-esteem [48].

Comfort

The comfort of rollators was generally rated highly [2,22,48]. A lower level of comfort was often associated with a high level of effort. In Brandt et al. [2] some users reported pain in the arms and shoulders or general fatigue after using the rollator due to difficulties caused by, for example, uneven or sloping pavements [2]. Further discomfort was described because of the need of lifting the rollator into busses [58] or because of an improper handle placement [59]. The evaluation of the comfort and efficiency of rollators to support walking, however, depends on the individual condition of the user and the context of use. The literature displayed two examples of different individual physical conditions: Patients with Parkinson disease walked more slowly using a walker [20], while Haddas et al. [13] examined the effect of walking with a rollator for patients with adult degenerative scoliosis. In the latter case, the authors concluded that rollators “…promote less efficient gait by decreasing trunk muscle activations and potentially increasing spine and lower extremity joint load” [13,p.465]. In addition, Schülein et al. [62] showed that the experience in rollator use may also play a role. Thus, rollators improved various gait parameters in different geriatric cohorts, but the strongest benefits were recorded for experienced rollator users [62]. Regarding the context of use, the usage of a rollator led to an improvement in the gait pattern on level ground [9,63], but also a deterioration in the gait pattern when walking uphill and downhill with the rollator [63]. Downhill and uphill walking, especially on uneven terrain, or walking backwards was considered also as difficult and exhausting [57]. Hansson et al. [5] found that changes in user’ pace and step length occur when they performed these more difficult tasks with a rollator [5]. Regarding the stability of people and rollators, differences could be found between walking straight line and more complex walking task [6].

Rollator baskets were evaluated as efficient and comfortable transport solutions. Users utilised them as carrying supports for everyday tasks such as carrying meals and drinks [8], for doing the laundry [8,58], for shopping [34], or to transport their portable oxygen [22]. Complex rollator tasks, such as walking while carrying things, or passing through doors are potentially more problematic and require more effort. In the Lindeman et al. [57] study, for example, walking through doors while using a rollator was slower than walking through a door unaided. Therefore, users rated mostly the unaided walking through doors as easier.

Individual product parts of rollators can also make the entire application more uncomfortable, in that they can be used only in a certain way due to their design or due to malfunction. For example, the back wheels of a rollator that do not rotate were considered to reduce sideward navigation. A large proportion of rollator users stated that the malfunctioning brakes on rollators during transfers from sitting to standing were a major problem [57]. Raijmakers [51] asked users about their complaints during rollator use. The most frequently expressed complaints were, 1. “‘the rollators’ brake cables are loose; 2. ‘the rollators’ castor wheels revolve’; and 3. ‘the rollator’s castor wheels get stuck’”. Other complaints were a poor product suspension, ineffective braking, poor directional control, and “…folding up when negotiating obstacles”. Castor wheels getting stuck and “folding up when negotiating obstacles” were considered as very serious complaints by the users, resulting in negative effects such as broken bones after accidents [51,p.200]. In Walsh & Petrie [53], a user could not use the brake on the left handle because of a weakened handgrip. The user also had complaints about the safety of the seat [53]. In 1997, Finkel [64] classified the seating options of rollators available at his time as potentially dangerous [64].

Safety & effectiveness

In some studies, users reported or were reported to have had accidents with the rollator, mainly falls. [4,57,58]. Pils et al. [65] examined predictors of fall events for the elderly during rehabilitation after hip fractures. They pointed out that patients with rollators, using a commode chair during the day and diapers during the night, had a significantly higher risk of falling in the rehabilitation phase than patients with crutches and the same nighttime urinary incontinence [65]. On the other hand, according to Vogt et al. [66], in the context of rehabilitation interventions, the use of a rollator could improve self-confidence and partially restore or maintain motor skills [66]. There is also an opinion that rollators prevent falls or reduce the consequences of falls by causing less intense trauma injuries [4,59].

Users described the positive safety aspect that rollators give them [4,33,34,48,59] and the effectiveness of the rollator in maintaining individual mobility [2,22,48]. From a safety perspective, device features like the possibility of sitting on the rollator and holding onto the rollator handles allow users to move without fear of tripping and falling due to sudden dizziness or balance issues. These features enable users to tackle distances that they might otherwise avoid due to the fear of not having available seating options or experiencing sudden dizziness [3,8,22,33,34]. The increased safety also led to a reduction in family members’ anxiety, as they were less concerned about tripping by their mobility-impaired relatives [34]. As a safety feature, the rollator can be used effectively for symptom relief through a seated tripod position (or simply by placing both hands on the handles) for certain disease symptoms, such as shortness of breath, [22]. Clinical trials have also reported reductions in shortness of breath and hypoxaemia in patients with chronic airway limitation using a rollator, while also noting an improvement in walking distance [11,22,24–27]. However, results from Probst et al. [26] showed that, “…the most disabled patients are the ones who benefit most from the use of a rollator” [26,p.1106].

Dimensions & weight

The dimensional problems reported in the studies related to the size of the rollator and its foldability. Rollators takes too much space in the car [2], are not easy to fold and unfold [2,51], and the most models are too bulky for indoor use and, difficult to push on floor coverings [22,34,59]. Because of the size of the rollator, users automatically need more space while walking and additional storage areas in front of stairs or doors which they cannot pass [33,59]. Because of this fact and because of the risk of theft of the rollator, users reported a limited choice of shops to visit [58]. One user reported that there are various factors she thinks about before using her rollator in the retirement home or outdoor: She considered factors like how crowded the place would be and how long the walking distance, especially in terms of potential fatigue [34]. User expressed varying feelings about having to occupy more space in public like this. In some cases, they felt like others did not look at them at all or even being invisible, while in other situations they felt very visible and meeting negative public attitudes [33]. According to Löfqvist et al. [58], the feeling of taking up too much public space and disturbing other people with the rollator can hinder social participation, as possibly users want to avoid this. When problems with the product weight occurred, it was due to the fact that the rollator was too heavy to handle, to overcome obstacles, or to lift the device [2,51,59], especially when high rollator weight met individual physical weaknesses [3]. Women were more often less satisfied with the product weight than men [22].

Adjustments & durability

Users expressed occasional problems with adjustments like changing the height of the handles or being unable to easily fit shopping baskets onto their rollators [2,59]. In a study gathering data about rollator users living in a retirement-centre, incorrect adjustment of the handle-height was the main misuse [67]. As for the height of the handles, Takanokura [68] believed that users should adapt their handle height to their own individual training condition [68]. According to Takanokura [69], the negative effects of handles being too low include an increased risk of accidents due to reduced visibility, as user tend to look down at the ground. This begins when the critical height of the handles falls below 48% of the user’s height [69]. Aside from the QUEST 2.0 assessment, see Table 6, no content as to durability was categorizable.

Dimension: service satisfaction

Professional service

Rollator users reported having a lack of information in case of problems with the mobility device (e.g., repairs and adjustments) [2,51] and problems during the prescription process, in which some users were not involved [3,51] or were forced to accept the prescription by appeals to fear, “‘I was told either get a device or stay at home’… ‘…my rheumatologist said ‘if you don’t use it you’re going to be in a wheelchair’” [3,p.51]. Samuelsson & Wressle [48], on the other hand, reported a high proportion of rollator users whose needs and wishes were considered by the prescribers [48]. Many of the users did get a sort of training but a large part of them did not feel well-trained or that they received proper instructions [2,53]. According to Walsh & Petrie [53], in the UK, rollators were provided by physiotherapists (NHS), who had no alternatives for users if the rollators did not fit [53]. In Japan, to prevent and reduce negative effects of misfit and malfunction, “guiding officers” provide an individual rollator customization and adjustment as soon as the walking aids are approved [17]. In Liu’s [67] study, about 80% of users in a retirement-centre in the USA obtained their rollator without any advice or support from healthcare professionals [67]. Holz et al. [3] reported on two users who bought rollators of their own accord because they perceived a rollator as their last resort. Without any official recommendation from a health care worker, they did not get any kind of training, but they were able to teach and inform themselves on the rollator use [3]. Liu [67] and Probst et al. [26] see the need for rollator training to avoid misuse and thus increase efficiency and product comfort. Holz et al. [3] reported a positive effect of a formal training, which included rollator adjustments and product instructions like brake management, affecting confidence [3].

Follow-up service, repairs & servicing, service delivery

In the study of Samuelsson & Wressle [48], less than 30% of users received a follow-up, while in Walsh & Petrie [53] neither user had a follow-up. The usage problems reported in the study by Brandt et al. [2] can be related to a lack of follow-up care. In the survey by Raijmakers [51], the lack of regular rollator checks was identified as a cause of rollator problems. Kitajima et al. [17] reported on regular repairs und services for rollator users in Japan, which helped the mostly elderly users to maintain the operability of the device. In this regard users described a quality and performance reduction over time, such as “…loosening of screws and frame distortion” [17]. Raijmakers [51] mentioned that a quarter of dissatisfied rollator users reported unresolved rollator problems or incorrect rollator maintenances. In general, however, users are very hesitant to report problems with rollators. For this reason, people often try to solve the problems themselves. When reported issues were not resolved satisfactorily, users often felt embarrassed to report the same issue again [51]. Liu [67] reported that about 17% of the observed rollators in a retirement-centre had maintenance problems [67]. In Raijmaker’s [51] survey, more than half of the users did not get any kind of rollator instructions, nor information about the date of the delivery [51].

Discussion

The aim of this systematic narrative literature review was to summarize aspects of the usability of rollators from different study designs with different methodological backgrounds. The synthesis of the usability aspects is intended to serve the better understanding of the human-rollator interaction and to be used for possible, future human-centred rollator design. In addressing our main questions in this study, three key areas emerged, which are highlighted in the following discussion:

(H1) Using the QUEST 2.0 dimensions to systematically record rollator usability components

We found no publications that deal explicitly with the topic of usability or human-centred quality of rollators. In this regard, QUEST 2.0, with its multidimensional understanding of assistive device satisfaction [49], was suitable and could be used to address usability aspects successfully. However, using QUEST 2.0 to assess usability aspects may give the false impression that a comprehensive evaluation of the usability of rollators has been achieved. QUEST 2.0 is meant to primarily measure user satisfaction and therefore may not capture all the specific details required for a thorough usability assessment. Nevertheless, QUEST 2.0 was able to show the different requirements for product satisfaction in the various phases of rollator use, from the purchase of the rollator to its actual use. This was mainly achieved by considering the items on the service dimension, which enables an assessment of rollators as a service-product system. Aspects of rollator satisfaction that change over time [3,33,48,61], and thus the assessment of usability, which may result from experience in use, however, are not consciously included in the QUEST 2.0 items. The items also lack aspects that include the use of rollators in terms of sustainability and the associated conservation of resources. This may become important as such sustainability aspects could also influence the acceptance and usability of assistive devices on an individual consumer basis in the nearer future. The aspect of sustainability was not addressed in the publications included. This can also possibly be seen in the item “Durability”, which could be classified as a partial aspect of the sustainability of products. Of all the QUEST 2.0 items, “Durability” was coded as the least frequent with three out of 126 codes.

(H2) Different coding frequency of rollator requirements and the satisfaction paradox

By using the device and service dimensions, requirements for rollators could be worked out. Items of the device dimension were coded most frequently, accounting for 82% of all codes. The leading items were “Ease of use” (28 codes), “Comfort” (20 codes) and “Safety” (15 codes). This contrasts with the service dimension (18%), where none of the four inherent items occupies a real key position, apart perhaps from “Professional services” with eight codes. However, this quantitative difference in coding frequency as compared to the device dimension should not be understood as service aspects of the rollators having a lower importance. It is precisely these presumably few found statements that open large areas of discussion. For example, forcing the use of a rollator through fear and threats of consequences [3] should be rejected, especially, but not only, in the case of vulnerable user groups. Other problems that arise in the service dimension include a lack of choice of rollators during the prescription process [53], lack of device training [2,3,53], and a lack of follow-up services in terms of readjustments and maintenance of the rollators [2,17,48,51,53,67]. This often leads to a situation where users try to solve their service problems themselves or, if they have expressed their problems and these have not been solved adequately, they often to hesitate to voice them again [51]. Positive examples, however, show how necessary and important well-functioning product service systems are for the safe and correct use of rollators [3,17].

This is in line with Boerema et al.’s statements, that “[t]he actual needs are often of a nonmaterialistic nature, like the need for being somewhere or the need for information, for which a single product is not always the best answer. A solution here is to shift the design of mobility aids to product service systems. Such systems are a combination of products and services for fulfilling a need (or value) and provide end-users with solutions of higher quality” [36,p.82]. Future usability engineering for rollators should therefore also focus more on service aspects in design development. This could possibly address the problems found in the literature review regarding purchase, maintenance, and training. To this end, it will be important to involve all stakeholders such as prescribers, maintainers, and rollator trainers.

The processing of the results offers another focus of the discussion: the satisfaction paradox. This paradox is generated by the existence of a generally high level of product satisfaction in the included studies [2,3,36,47,48,51], with simultaneous dissatisfaction in individual product items or for certain user groups [2]. It manifests itself in statements, like Raijmaker’s [51], in which users are generally satisfied with rollators, but less so with their own rollator model [51]. We have found studies in which users are satisfied with the ease of use of the rollator [2,22,48,53]. However, we have also found studies about the necessity to learn new skills or to use creative solutions [3,33,52], which may indicates a difficult use. This may be due to the heterogeneity of the included studies and the diversity and complexity of human-rollator interactions but shows that no conclusive statements can be made in this regard. The complexity of interactions between humans and rollators arises from the highly diverse individual lifeworld of each user. These lifeworlds are characterized by various factors including different physical and mental-cognitive abilities, life situations, social contexts, and financial circumstances. This results in numerous different use cases that often cannot adequately be addressed with one common rollator model.

A recent study by Caronni et al. [70] confirm the psychometric strengths of the successor QUEST 2.0 for the device subscale but conclude their instrument evaluations with criticism: “QUEST 2.0–device suffers a severe ceiling effect, poor item targeting of the respondents’ sample, low reliability, and lack of measurement invariance. Regarding this last point, total scores of the QUEST 2.0–device should not be used to compare satisfaction in users of different device types” [70,p.16]. This issue could offer a possible explanation for differences in satisfaction ratings. Nevertheless, from a pragmatic point of view, the dimensions of the QUEST 2.0 were suitable as categories for processing and summarizing the usability aspects of rollators.

(H3) Addressing the usability of rollators through different disciplines

The leading disciplines included in this review were Physiotherapy (42%), Engineering (16%), and Health Science (16%) with a majority of literature using quantitative study designs (56%), followed by mixed methods (31%). Only a small amount used qualitative study designs (13%). The methods used ranged from qualitative methods such as interviews [3,7,33,34,36,51–53,57,59,61] and observations [7,8,22,52,60], to quantitative methods such as experimental studies [4–7,9–13,20, 21,23–27,54–57,60,62,63,66] and questionnaires [2,11,17,22–24,47,48,51,60,67] to theoretical design studies [64,68,69]. It is surprising that so little has been published on this topic from a nursing science perspective [7,33]. It is precisely the maintenance of mobility and thus the interaction between human and their assistive devices, which often takes up a large part of the daily nursing work. However, it is possible that nursing science activities are included in interdisciplinary research projects, which, at 64%, also form the majority of the included publications.

Internationally, Canada (24% off all publications) and Sweden (20%) have the largest share of the included publications, whereas from a continental point of view, Europe published the largest number of publications (51%), followed by North America (33%). It should be noted that all studies originate from industrialised countries with a high standard of living. Studies from Central and South America, Africa, or Asia (except Japan), however, are completely absent. This may be due to a language bias, as only English and German publications were included, but it could also be due to different infrastructure requirements. The use of a rollator requires walkways and street infrastructure in good condition [7,33,51,60]. In contexts of use where there is no good walking infrastructure, the use of a walker in the sense of e.g., a “zimmer frame” without wheels may be more effective and efficient.

Limitations

Limitations of this review include possible language bias, as only English and German publications were included. Therefore, it is highly likely that some global perspectives on rollator use were not included. In addition, due to the different terminology related to rollators, it is possible that publications were wrongly excluded or fell through the search grid in case of ambiguity. Furthermore, the literature review was only conducted using positive search terms. Therefore, it is possible that future research using negative search terms such as “frustration”, “struggle”, etc., may yield additional publications. As there are no authors with an engineering background, we concentrated on health-related and interdisciplinary databases such as Academic Search Elite. Therefore, it is possible that articles found exclusively in purely technical databases are not considered in this narrative review. It is also possible that the device and service dimensions, used as theory driven approach, did not consider all aspects of the usability of rollators.

Conclusion

This is the first systematic narrative literature review to comprehensively address and summarize aspects of the usability of rollators and their use. The explicated and discussed results open up further fields of research, but do not allow a generalised statement about the usability aspects of rollators. Nevertheless, the results suggest that a deeper understanding of human-rollator interactions could bring benefits for their day-to-day use. Usability aspects, such as the need to change from rollators as purely technical devices to product-service systems, could be ensured through a stronger human-centredness in research and design processes. In general, there is a need for research that explicitly deals with usability aspects of rollator use and discusses, classifies, and thus validates usability in a participatory manner with the users and the fields of practice before they are fed into a technical operationalisation. A survey of product satisfaction, in addition to the classical usability tests, could be a key to achieving this goal. Methodologically, in addition to the use of qualitative methods such as interviews and ethnographic field research, standardised instruments such as QUEST 2.0 could be successful. For a standardised survey of satisfaction with assistive devices, further instruments should urgently be analysed, adapted, or newly developed. Above all, disciplines close to the user, such as nursing sciences, should become more involved in international technical research projects and initiate them. In addition, funding institutions must recognise the importance of seemingly simple technical assistive devices for securing home and inpatient care and fund research projects accordingly.

Acknowledgements

Thanks go to Norma Huss (Esslingen University), who helped to identify the English search terms and gave access to original English-language literature. Many thanks also to Alma Stankovic (Esslingen University), who did an excellent job proofreading this article.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the German Federal Ministry of Education and Research (BMBF) under the funding code [No. 03FHP115].

Notes on contributors

Marcel Schmucker

Marcel Schmucker is currently a nursing science research assistant at the Esslingen University of Applied Sciences in the research focus of “Interdisciplinary Collaboration of Nursing, Medicine and Technology” under the direction of Professor Astrid Elsbernd. He is also currently a doctoral student on the topic of “Usability of Rollators”, which is being supervised by Professor Cornelia Mahler in cooperation with the Medical Faculty of the University of Tübingen.

Andreas Küpper

Andreas Küpper is a nursing science research assistant in the field of "Interdisciplinary Collaboration of Nursing, Medicine and Technology" at the Esslingen University of Applied Sciences. Currently he is a doctoral student in nursing science.

Cornelia Mahler

Cornelia Mahler is professor in nursing science and director of the Department of Nursing Science at the University Hospital Tübingen. She leads the academic bachelor nursing program at the Medical Faculty, University of Tübingen. Her research interests are interprofessional education and collaboration, the use of digital technology in health care, and non-pharmacological nursing interventions.

Astrid Elsbernd

Astrid Elsbernd is professor in nursing science at the Esslingen University of Applied Sciences. She researches and teaches in the areas of quality development, assistive care technology, and sustainability in nursing care.