Predicting emotional consequences of disorganization among adults with neurodevelopmental disorders: a structural equation model

Abstract

Purpose

Previous studies exhibited differences in sensory processing, motor coordination, metacognitive executive functions (EF-MI), and sleep quality among adults with neurodevelopmental disorders (NDD). This study aims to find relationships between those abilities and organization-in-time, focusing on emotional responses after decreased organization abilities.

Materials and methods

This is a secondary data analysis of a larger sample from three previous studies conducted in one laboratory. Data were collected from 290 adults; 149 with NDD and 141 sex- and age- (20–50 years) matched controls completed the Adolescent/Adult Sensory Profile, Adult Developmental Coordination Disorder, Adults Behavioral Rating Inventory of Executive Functions, Mini Sleep, and Time Organization and Participation questionnaires. Structural equation model (SEM) analysed relationships and variable prediction.

Results

Significant between-group differences were found for all variables; SEM indicated similar paths in both groups. Sensory processing affected EF-MI and sleep quality and significantly correlated with motor coordination, affecting EF-MI; EF-MI affected organization-in-time. Sleep quality significantly affected organization-in-time, affecting emotional responses.

Conclusions

Sensory, motor, EF, and sleep differences were associated with decreased organization-in-time abilities of adults with NDD, adversely affecting their emotional well-being. Early detection of such differences and targeted interventions may improve daily functioning and life quality and prevent negative emotional implications.

IMPLICATIONS FOR REHABILITATION

• Neurodevelopmental disorders (NDD) emerging early in development affect lifelong well-being, and personal, social, academic, and occupational function.

• Adults with NDD may experience reduced quality of life due to ineffective time organization and life management.

• Ineffective time organization and consequence negative emotional responses are tied with deficient sensory processing, motor coordination, metacognitive executive function abilities, and sleep quality.

• Early diagnosis of such deficiencies following by targeted intervention may enhance daily functioning, reduce emotional challenges, and improve overall life outcomes.

Keywords:

• Neurodevelopmental disorder
• specific learning disorder
• attention-deficit/hyperactivity disorder
• ICF
• organization-in-time
• structural equation model

Introduction

Neurodevelopmental disorders (NDD) are lifelong health conditions originating during early development. They are characterized by differences in personal, social, academic, or occupational functioning and encompass a broad range of neurological health conditions. Attention-deficit/hyperactivity disorder (ADHD) and specific learning disorders (SLD) are highly common NDD [1]. The reported prevalence of ADHD symptoms in adulthood ranges from 2.5% to 5.0% [2]. The rate of adulthood SLD is unknown but estimated at around 4% [1].

These health conditions and their characteristics may lead to daily functional limitations related to long-term emotional, social, and occupational outcomes [3–7]. It is assumed that adults with ADHD may experience decreased quality of life due to less effective organization of their time [7,8].

This study is based on the World Health Organization’s [9] International Classification of Functioning Disability and Health (ICF) framework, which views NDD as health conditions. This internationally recognized, comprehensive health-related perspective enables the understanding of people’s daily organization-in-time abilities through various factors, including body functions [10,11]. These functions encompass sensory processing, motor coordination, executive functions (EF), and sleep functions [9].

Organization-in-time

Organization-in-time ability reflects a person’s ability to organize their time relative to actual, concrete daily performance. Wennberg [12] defined daily time management as the ability to perform and complete everyday activities in the correct sequence and within specific time frames and identified two related ICF activity and participation codes: managing one’s life (d2305) and adapting to time demands (d2306). The estimation of time to perform daily activities, which poses challenges for adults with SLD [13], is a component of this ability [14]. This article uses the closely related term, organization-in-time ability, which is also classified under activity and participation and pertains to the ICF code for managing one’s life (d2308).

Organization-in-time has crucial effects on a person’s self-directed feelings, autonomy, and life motivation [14]. Effectively organizing time is essential for participation in everyday life at home, work, and academic environments and during play and leisure activities [15]. Poor organization-in-time abilities, as found in adults with SLD or ADHD, can lead to disrupted work–life balance and decreased well-being and quality of life [7,8,13,16].

Emotional consequences following unsuccessful organization-in-time

One component of organization-in-time ability reflects the experience of frequent emotional responses following unsuccessful organization-in-time [14]. It highlights the emotional consequences that arise from differences in daily organization-in-time and its functional implications. As a result of daily confrontations in diverse life domains, adults with SLD/ADHD may experience frustration and even reduced global and mental health if their sensory, motor, cognitive, or sleep differences are not understood or acknowledged [17].

Sensory processing

As an ICF body function [9], sensory processing pertains to how people receive, incorporate, and structure incoming sensory information [18]. Dunn’s [19] theoretical model of sensory processing explores connections between the neurological threshold and behavioural-response-regulation spectrums. It delineates four sensory-processing patterns stemming from those relationships: low registration, sensation-seeking, sensitivity to stimuli, and sensation-avoiding. Although most people with neurotypical development do not struggle with sensory-processing differences, some exhibit extreme sensory-processing patterns [20].

Previous studies indicated that adults with SLD or ADHD had more sensory-processing differences in multiple life domains than adults without NDD [4,21]. They exhibit decreased performance, activity avoidance, and affective mental health problems, such as anxiety and depression [4,22–24].

Motor coordination

Coordinating voluntary movements, another ICF body function [9], can manifest as motor coordination. Developmental coordination disorder (DCD) is diagnosed when acquiring and executing coordinated motor skills is significantly decreased, even considering the person’s age and opportunity for skill learning and use. Decreased motor coordination might manifest in dropping and bumping into objects or difficulty catching objects, using scissors, handwriting, riding a bike, or participating in sports [1]. These symptoms affect daily functioning with changes in social behaviours, such as avoiding clubbing, dancing [25], and other leisure activities. Compared to controls, adults with DCD symptoms take longer and may require more effort to complete daily tasks involving fine and gross motor skills and spatial orientation (e.g., driving), resulting in less efficient and lower quality performance. They also report negative emotional effects of these limitations [26,27].

Although 67% of adults with SLD were classified as having DCD symptoms based on their self-reports [28], studies of motor coordination among adults with SLD/ADHD have been rare [25,29]. However, studies have shown that some children with SLD and ADHD demonstrate DCD symptoms [e.g., 30,31] and estimated that such symptoms exist in 50% of children with ADHD [e.g., 30,32].

Executive functions

Beside modulating sensory responses and efficient motor coordination, organizing time effectively requires adequate EF, such as planning, decision-making, and attention [14,33]. Executive functions are higher-level cognitive functions required to perform and participate effectively in complex, self-directed activities [34,35]. These abilities allow people to achieve short- and long-term goals, modify their thinking and actions [36], and engage in successful problem-solving and planning [37]. They comprise two close but separate executive abilities: metacognitive and motivational–emotional [e.g., 38]. Differences in EF have been reported in people with SLD [7], ADHD [39], and DCD [40] and suggested as a common mechanism in NDD [e.g., 41].

Graham [42] suggested that a better understanding of EF among people with NDD could lead to a better understanding of their aetiology. Despite evidence that motor and sensory-processing patterns among adults with neurotypical development [20] and sensory functions among adults with SLD [43] can predict EF, there is no complete picture of their relationship in adults with ADHD and SLD. Considering previous research [43,44], this study focuses on five domains that tap the executive regulation of cognitive problem-solving, deemed “metacognition”: initiate, working memory, plan/organize, organization of materials, and monitor [45].

Sleep quality

Sleep functions also play a vital role in daily function. The ICF categorizes sleep—including its amount, onset, maintenance, and quality—as a specific mental body function [9]. Poor sleep refers mainly to insomnia, the dissatisfaction with sleep quantity, or quality causing clinically significant distress or difficulty [34]. Decreased sleep quality has been found among adults with SLD [21] and ADHD [4,46]. The literature emphasizes that sleep is essential to performing daily activities and occupations [32,47]. A relationship between sleep quality and cognitive, emotional, and functional abilities has been reported among adults with ADHD [48]. However, studies on the effects of decreased sleep on the daily functioning of adults with NDD are scarce.

Study Rationale and Aims

Despite the possible implications of these differences on the mental health, self-esteem, and well-being of adults with NDD, research on their daily functional characteristics has been scarce [49,50]. Nevertheless, it is essential to identify the relationships among these body functions, organization-in-time abilities, and subsequent emotional responses following decreased organization-in-time. This analysis will enhance the understanding of the broader implications for adults with NDD. Figure 1 visually represents a theoretical model of these relationships.

Figure 1. Theoretical model for the relationships between sensory processing, motor coordination, executive functions, sleep quality, and organization-in-time abilities and emotional responses.

Visual representation of a theoretical model depicting the intricate relationship between various health condition characteristics and their impact on functional behaviour.

This study is a secondary data analysis of a larger sample from three previous studies conducted in one laboratory. It aims to identify relationships among these body functions and predict the emotional consequences of disorganization-in-time among adults with SLD and ADHD due to their high incidence and frequent co-occurrence in adults with NDD [49,51,52]. Considering the results of previous studies, we hypothesize that: (a) significant differences between a sample of adults with NDD and controls in their sensory, motor, EF, and sleep body functions, as reflected in their daily functions, will be observed; (b) a significantly higher percentage of the group with NDD will show a decrease in these body functions; and (c) sensory, motor, EF and sleep quality will predict organization-in-time abilities and the emotional consequences of disorganization.

Materials and methods

Participants

The sample comprised 290 participants: 149 in the group with NDD and 141 in the control group, matched for age and sex (self-defined gender). This sample size surpasses the theoretically required number of 256 participants, calculated using statistical parameters at a 95% probability level, 80% statistical power, 16 observed variables, 6 latent variables, and an effect size of 0.3 [53].

Inclusion criteria for the entire sample were ages 20–50 years, ability to write Hebrew at a native-language level, intact or corrected vision and hearing, no physical or neurological medical observations, and generally healthy without chronic disease or significant injuries that might affect daily function. Subjects were divided into the research group (participants with NDD) and the control group (participants without NDD) based on their self-reports in the studies and on their previous professional diagnoses.

Specifically, participants in the control group self-declared that they were without ADHD or SLD diagnoses. Participants in the research group were people with SLD (with or without ADHD symptoms) or ADHD diagnoses, based on their self-reports or professional diagnoses (i.e., psychologists specializing in SLD). Participants with SLD were also diagnosed with ADHD symptoms based on the Adult ADHD Self-Report Scale (ASRS-V1.1) [54]. For those diagnosed with ADHD, a formal medical diagnosis by an expert neurologist, psychiatrist, or family doctor based on the Diagnostic and Statistical Manual of Mental Disorders (5th edition) criteria [34] was required. Symptoms consistent with ADHD [55] were also confirmed by the ASRS v1.1 final score or medium-to-high probability of ADHD according to the Brown Attention-Deficit Disorder Scales [56,57]. In addition, participants with an ADHD diagnosis were asked whether they had previously been diagnosed with SLD.

Procedure

We used convenience sampling to recruit participants through social media in the three previous related studies. Researchers asked potential participants initial questions based on the inclusion criteria to confirm their eligibility for the research group or control group. Participants with NDD were asked to provide documentation to confirm their diagnoses.

The Ethics Committee for Human Subject Research at the University of Haifa approved the three related studies (confirmations No. 170/10, No. 032/17, and No. 457/18). During individual meetings with the researcher, which took place in a quiet area to ensure no interruptions, participants signed written informed consent forms and completed the sociodemographic questionnaire and other evaluations.

Measures

Time Organization and Participation Scale

The Time Organization and Participation Scale (TOPS) [14] examines time organization ability while performing daily tasks. The questionnaire includes three parts comprising 35 items scored on a five-point scale; a lower score indicates a greater lack of organization-in-time. Two additional questions are for clinical use only. Part A (20 items) evaluates the performance of each daily activity at an appropriate pace, as expected by the environment. It uses a scale of 5 (always), 4 (usually), 3 (sometimes), 2 (rarely), and 1 (never). Part B (five items) examines the way of organizing the performance over the day or within a certain time on a scale of 5 (excellent) to 1 (very bad). Part C (eight items) includes a report of emotional responses following unsuccessful organization of time on a scale of 5 (never), 4 (rarely), 3 (sometimes), 2 (usually), and 1 (always).

The emotional response share a lack of motivation to perform, sadness, frustration, anger, crying, outbursts toward family members or friends, and stress [14]. Thus, lower TOPS scores (cutoff scores: Part A = 3.18, Part B = 3.11, Part C = 3.16) indicate a higher probability for more limitations in time organization and participation in daily tasks. High internal consistency was reported for Parts A, B, and C (0.87 < α  < 0.92), and discriminant validity was reported for differences in age groups [14] and between adults with and without SLD [13].

Adolescent/Adult Sensory Profile

The Adolescent/Adult Sensory Profile (AASP) is a 60-item self-reported sensory-processing questionnaire based on Dunn’s model of sensory processing. Using a five-point Likert scale from 1 (almost never) to 5 (almost always) for each item, the participant indicates how often they respond to a sensory event in the manner described. For scoring, the items are sorted into four subscales reflecting sensory-processing patterns: low registration (inability to perceive sensations and exhibiting inattentive behaviours), sensation-seeking (searching for intense sensations, e.g., strong tastes, loud sounds, and arousing visual stimuli), sensory sensitivity (inattention to sensory input, e.g., hearing or smelling), and sensation-avoiding (keeping distractions to a minimum) [58]. A validation process conducted for the Hebrew version indicated good internal consistency. Psychometric properties and norms were published for adults aged 18–64 years for each subscale [59].

Adult Developmental Coordination Disorder Checklist

The Adult Developmental Coordination Disorder Checklist (ADC) [25] screening tool identifies youth and adults at risk for DCD. It is a 40-item, Hebrew, self-report questionnaire that examines respondents’ motor coordination abilities. The questionnaire includes three subscales that evaluate (a) difficulties the respondent experienced as a child (10 items), (b) current symptoms (10 items), and (c) current symptoms manifested by others (20 items). Each item is scored from 1 (never) to 4 (always), with higher scores indicating a higher risk for DCD. Summary scores of 80 and above indicate being at risk for DCD (probable); scores of 90 and above indicate DCD. Internal reliability levels for the whole scale (α = 0.953) and three subscales (0.873 < α  < 0.914) have been established [25].

Behavioral Rating Inventory of Executive functions-Adolescent/Adult version

The Behavioral Rating Inventory of Executive Functions-Adolescent/Adult version (BRIEF-A) [60] is a self-report ecological validity questionnaire reflecting EF abilities through daily function. It is designated for adults aged 18–90 years [61] and is appropriate for people with developmental, neurological, and psychiatric disorders [43,62]. Its 75 items include nine subscales divided into two index scores: a behavioural regulation index and a metacognition index. A global executive composite score is also achieved [60].

In this study, we focused on the BRIEF-A metacognitive index, comprising five of the nine scales: initiate, working memory, plan/organize, task monitor, and organization of materials [63]. For each metacognitive index item, participants indicate how often they behave as described on a three-point scale; higher ratings indicate more EF deficiency.

These subscales are standardized to produce t-scores according to age and sex norms. The expected normative score for the whole scale is t = 50; above 65 signifies clinical difficulty. The BRIEF-A has moderate to high internal consistency (α = 0.58–0.92), high test–retest stability (α = 0.82–0.94), and high test–retest reliability (r = 0.91–0.94) [63,64].

Mini Sleep Questionnaire

The Mini Sleep Questionnaire (MSQ) [65] is a self-report measure examining respondents’ sleep quality and insomnia risk. Using a seven-point Likert scale, respondents indicate how often they face different sleep difficulties; a higher score indicates more severe sleep difficulties. Natale et al. [66] found the questionnaire to have good internal consistency and that two factors explained about 50% of the total variance, with loading values higher than 0.50 (excluding Item 6, snoring). Fabbri et al. [67] labelled the sleep (Items 1, 2, 3, 7, and 10) and wake (Items 4, 5, 8, and 9) dimensions. Sleep–wake quality is measured by the total score, with higher scores indicating more sleeping problems (10–24 points for good sleep–wake quality; 25–27 points for mild sleep–wake difficulties; 28–30 points for moderate sleep–wake difficulties; and >30 points for severe sleep–wake difficulties) [65].

Data analyses

This study is a secondary data analysis of a larger sample from three previous studies that used the same inclusion and exclusion criteria and variables analysed in this study [4,13,29,43,68]. Descriptive statistics were conducted using frequencies for categorical variables (e.g., sex) and means with standard deviations for continuous variables (e.g., age). We compared the groups using Chi-squared and independent t-tests and analysed the internal reliability of each test’s domain with Cronbach’s alpha. A multivariate analysis of variance (MANOVA) was conducted to examine between-group differences in the tests’ domain scores and ability percentiles. We used IBM SPSS (ver. 27) for descriptive statistics and correlations and MANOVA and AMOS software (ver. 27) to implement the structural equation model (SEM).

The SEM was implemented to strengthen the theoretical understanding of functional behaviour and provide insight into individual abilities. It divided behaviour into components and analysed them sequentially. The model was evaluated for the whole sample and then for each group. We calculated missing data values (<5%) before the SEM analysis to ensure a complete dataset. The following indices were used to evaluate the model: Chi-squared, which is acceptable when the value is not significant; the goodness of fit index (GFI); the comparative fit index (CFI); the non-normed fit index, with adequate values above 0.90 and excellent fit above 0.95; and the root mean square error of approximation (RMSEA), with adequate values less than 0.08 and excellent fit less than 0.06 [69].

Figure 2 illustrates the latent variables (circles) and observed variables (squares). Due to its low degree of effect, the AASP sensation-seeking domain was excluded from the model. In addition, given the importance of the emotional responses following daily functional experiences of disorganization, we separated the TOPS Part C in the model (this part represents emotional responses tied to decreased functional behaviour). A path analysis using SEM was conducted to assess the meditation relationships between the study variables.

Figure 2. Theoretical model representing latent and observed variable.

An illustration of a SEM showing latent variables (circles) and observed variables (squares).

We used the bootstrapping method to examine the models’ indirect effects. The key principle underlying the bootstrapping procedure is that it enables the researcher to simulate repeated subsamples from an original database. Thus, it allows the assessment of parameter estimate stability and reporting the values with greater accuracy [70]. The significance level (p value) was 0.05.

Results

The research group included 30 (20%) adults diagnosed with only SLD, 57 (38%) adults with SLD accompanied with ADHD symptoms, and 62 (42%) adults with only ADHD. Table 1 shows the demographic characteristics of the research group (n = 149) and the control group (n = 141).

Table 1. Descriptive statistics by group.

Demographic	Group with NDD (n = 149)	Control group (n = 141)	t/ꭕ^2	p
Age in years; M (SD) Range	29.36 (5.90) 21–46	31.74 (6.80) 21–47	3.170	n.s.
Sex (% female)	65.80	69.50	0.461	n.s.
Family status (% stable relationship with a spouse)	38.90	48.20	4.828	0.034
Education (% university student)	52.00	63.80	4.124	0.043
Currently working (%)	83.20	86.50	0.614	n.s.
Currently student (%)	55.70	57.40	0.089	n.s.

Note. NDD = neurodevelopmental disorders.

No significant group differences were found for age, sex, or number of participants working or university students. Significant group differences were found for education: more control group participants than research group participants were academics. In addition, more control group participants indicated a stable relationship with a spouse. No significant correlation was found between those demographic variables and organization-in-time, sensory, motor, EF, and sleep variables.

Decreased organization-in-time, sensory processing, motor coordination, EF, and sleep quality: between-group comparison

Table 2 shows the MANOVA results for each questionnaire regarding participants’ organization-in-time abilities and body function characteristics. Except for the AASP’s sensation-seeking domain and sleep–wake quality, all variables had medium to strong effect sizes (η_p² = 0.03–0.53).

Table 2. MANOVA for questionnaire domains.

Questionnaire/variable	Group with NDD	Control group	F	ηp²
	M (SD)
TOPS, F(3,285) = 54.90, p <.001, ηp² = 0.366
	n = 149	n = 139	F(1,287)
TOPS-A	3.51 (0.79)	4.28 (0.57)	89.400***	0.24
TOPS-B	2.89 (0.83)	3.88 (0.66)	125.400***	0.30
TOPS-C	3.14 (0.58)	3.89 (0.65)	109.210***	0.28
AASP, F (4,285) = 42.05, p <.001, ηp² = 0.37
	n = 149	n = 141	F(1,288)
Low registration	37.31 (7.43)	27.63 (5.88)	149.92***	0.34
Sensitivity	44.64 (9.06)	34.62 (7.55)	103.97***	0.26
Seeking	46.56 (6.79)	46.60 (6.79)	.002	.001
Avoidance	40.57 (8.60)	33.86 (7.45)	50.06***	0.48
ADC, F(3,281) = 21.95, p <.001, ηp² = 0.190
	n = 144	n = 141	F(1,283)
ADC-A	18.70 (7.39)	14.05 (3.88)	43.980***	0.13
ADC-B	18.55 (6.89)	13.47 (3.21)	63.230***	0.18
ADC-C	38.90 (11.67)	31.62 (6.14)	43.120***	0.13
BRIEF-MI, F(5,284) = 67.58, p<.001, ηp² = 0.543
	n = 149	n = 141	F(1,288)
Initiation	63.79 (11.68)	48.88 (9.86)	137.230***	0.32
Working memory	72.72 (12.08)	49.24 (9.74)	329.450***	0.53
Task monitor	65.99 (13.05)	49.01 (8.95)	165.030***	0.36
Environment organization	68.66 (12.63)	50.74 (8.84)	193.890***	0.40
Plan	60.69 (13.60)	47.33 (9.18)	95.050***	0.25
MSQ, F(2,288) = 50.37, p <.001, ηp² = 0.245
	n = 149	n = 141	F(1,288)/t
Wake	13.37 (4.16)	9. 49 (3.59)	71.65***	0.20
Sleep Sleep–wake sum	16.23 (5.01) 32.56 (8.30)	11.88 (3.79) 23.66 (6.32)	68.72*** t(288)=−10.22	0.19 .001

Note. ADC = Adult Developmental Coordination Disorder Checklist: -A = difficulty relating to others, -B = current function, -C = childhood function; AASP = Adolescent/Adult Sensory Profile; BRIEF = Behavior Rating Inventory of Executive Function: MI = metacognitive index; MSQ = Mini Sleep Questionnaire; NDD = neurodevelopmental disorders; TOPS = Time Organization and Participation Scale: -A = way of performing, -B = rhythm of performance, -C = emotional reactions.

***p < 0.001.

Significant group differences were found for all organization-in-time, sensory, motor coordination, EF, and sleep quality domains except sensation-seeking. In these domains, participants with NDD demonstrated decreased performance compared to the controls. Considering those results, we examined each construct’s degree and proportion of participants with two or more sensory, motor, or EF differences. Table 3 illustrates the results of each construct’s degree of differences.

Table 3. Frequencies of deficient function in organization-in-time domains, sensory processing, motor coordination, Executive functions, and sleep quality per cutoff points, norms, or mean final scores by group.

	Normal range/Cutoff score	Group with NDD (%)	Control group (%)
Time organization (TOPS)
A. Performing in appropriate pace	Mean score ≥ 3 (good)	81.2	97.9
	Mean score < 3 (deficient)	18.8	2.1
B. Daily organization	Good	48.3	92.2
	Deficient	51.7	7.8
C. Emotional responses due to lack of success	Good	60.4	91.4
	Deficient	39.6	8.6
Sensory processing (AASP)
Low registration
Under norm	15–23	2.7	2.7
Norm	24–35	36.2	66.7
Above norm	36–75	61.1	6.4
Seeking
Under norm	15–42	28.2	25.5
Norm	43–56	63.8	68.1
Above norm	57–75	8.1	6.4
Sensitivity
Under norm	26–41	0.7	14.9
Norm	42–75	40.3	68.8
Above norm	42–75	59.1	16.3
Avoiding
Under norm	15–26	4.0	16.3
Norm	27–41	53.7	70.2
Above norm	42–75	42.3	13.5
Motor coordination (ADC)	>80 neurotypical	54.4	93.6
	≥80 probable DCD	15.4	4.3
	≥90 DCD	30.2	2.1
Executive functions (BRIEF-A)
Behavioural Regulation Index	>65 = EF deficiency	45.0	5.0
Metacognition Index		61.7	4.3
Global executive composite		63.8	4.3
Sleep (MSQ) Sleep–wake quality	10–24 good sleep	18.0	57.4
	25–27 mild sleep	10.1	17.0
	28–30 moderate sleep	8.0	10.6
	>30 severe sleep difficulties	59.4	10.0

Note. TOPS = Time Organization and Participation Scale; AASP = Adolescent/Adult Sensory Profile; ADC = Adult Developmental Coordination Disorder Checklist; BRIEF-A = Behavior Rating Inventory of Executive Function; MSQ = Mini Sleep Questionnaire; NDD = neurodevelopmental disorders.

As presented in Table 3, 19% of the participants in the research group reported difficulty organizing their daily activities at an expected pace. More than 50% reported difficulty organizing their entire day, and 40% reported a high frequency of negative emotional responses. Only 2–9% of the participants in the control group reported deficient organization-in-time features in those domains (pace, whole day, and emotional responses). Except for the sensation-seeking domain, at least 45% of the research group dealt with abnormal sensory patterns (low registration, sensitivity, or avoidance) compared to around 32% of the control group. Further, 45% of the research group were at risk of DCD or probable DCD compared to 6% of the control group. More than 61% of the participants in the research group reported more EF deficiencies on the BRIEF-A metacognitive index and global executive composite compared to less than 5% of the participants in the control group, and 67% of them dealt with moderate to severe sleep deficits compared to 20% of the controls.

Table 4. Observed variable loadings with latent variables by group.

Loading			Group with NDD (n = 149)	Control group (n = 141)
LowReg_1	←	Sensory_processing	0.669	0.618
Sensitivity_1	←	Sensory_processing	0.885	0.919
Avoiding_1	←	Sensory_processing	0.816	0.795
ADC_A_1	←	Motor coordination	0.856	0.721
ADC_B_1	←	Motor coordination	0.873	0.749
ADC_C_1	←	Motor coordination	0.785	0.777
init_T_1	←	EF	0.856	0.873
WM_T_1	←	EF	0.757	0.795
plan_T_1	←	EF	0.929	0.842
taskm_T_1	←	EF	0.851	0.709
environ_T_1	←	EF	0.715	0.494
SleepSle_1	←	Sleep quality	0.395	0.426
SleepW_1	←	Sleep quality	0.454	0.382
M.TOPSA_1	←	Organization_time	0.748	0.601
M.TOPSB_1	←	Organization_time	0.822	0.802

Note. LowReg = low registration; ADC = Adult Developmental Coordination Disorder Checklist: -A = difficulty relating to others, -B = current function, -C = childhood function; EF = executive functions per Behavior Rating Inventory of Executive Function: init = initiation, WM = working memory, taskm = task monitor, environ = environment organization; SleepSle_1 = sleep; SleepW_1 = sleep–wake; MTOPS = Time Organization and Participation Scale: -A_1 = way of performing, -B_1 = rhythm of performance; NDD = neurodevelopmental disorders.

In each BRIEF-A metacognitive index domain, 2–10% of the control group had a deficiency (score > 65) in one or more domains compared to 21–76% of the research group. The higher percentage (76%) indicated decreased working memory. Related to sleep quality, whereas 20% of the control group reported moderate to severe sleep difficulties; 67% of the research group reported the same.

Further analysis of results from the research group indicated that seven (4.7%) participants dealt with both sensory processing and motor coordination decreases, 11 (7.4%) had decreased motor coordination and EF abilities, 31 (20.8%) had decreased sensory processing and EF abilities, and four (2.7%) had decreased sensory processing, motor coordination, and EF abilities. In sum, 35.6% of the participants in the group with NDD were confronted with two or more decreased sensory/motor/EF abilities.

Structural equation model

The SEM model for the sample achieved adequate fit indices, χ²(84) = 231.08, p < 0.001, CFI = 0.958, NFI = 0.936, GFI = 0.910, RMSEA = 0.078, SRMR = 0.053. Although p is significant, the value divided by the degrees of freedom (df) is smaller than 3 and, thus, adequate (χ²/df = 2.74). In addition, acceptable fit indices were found for the research group, χ²(81) = 152.50, p < 0.001, CFI = 0.943, NFI = 0.890, GFI = 0.90, RMSEA = 0.077, SRMR = 0.051, and the control group, χ²(81) = 109.9, p = 0.018, CFI = 0.970, NFI = 0.900, GFI = 0.917, RMSEA = 0.050, SRMR = 0.053, indicating that the model may be applied to either/both groups.

Figure 3 presents the relationships between the variables in each group. Correlation and regression coefficients levels for the group with NDD are bold above the lines; bold below the lines indicates levels for the group of controls. Double-headed (bidirectional) arrows represent correlations between variables, and single-headed (unidirectional) arrows represent regression coefficients. Correlations that were not significant are represented by a broken line. Table 4 presents the observed variable loadings with latent variables, described separately for each group.

Figure 3. Structural equation model: relationships and regression coefficients between organization-in-time and emotional responses and between these variables and executive functions, sensory processing, motor coordination, and sleep quality.

Graph illustrating the analysis of SEM, which examines the relationship and regression coefficients between organization-in-time and emotional responses and between these variables and executive functions, sensory processing, motor coordination, and sleep quality.

As presented in Figure 3, a significant correlation was found in both groups between sensory processing and motor coordination (research group: r = 0.43, p < 0.001; control group: r = 0.20, p = 0.046). A significant difference was found between the groups in these correlations (p = 0.015), indicating stronger relations among the group with NDD.

A significant effect was found in both groups between sensory processing and EF-MI (NDD: β = 0.61, p < 0.001; control: β = 0.31, p = 0.001) and between motor coordination and EF-MI (research group: β = 0.19, p < 0.05; control group: β = 0.40, p < 0.001). Significant differences were found between the groups in both paths (sensory processing and EF-MI: p = 0.001; motor coordination and EF-MI: p = 0.026).

A nonsignificant effect was found between EF-MI and sleep quality (research group: β = 0.22, p = 0.07; control group: β = 0.27, p = 0.154), whereas significant negative effect was found between EF-MI and organization-in-time in both groups (research group: β = −0.63, p < 0.001; control group: β = −0.68, p < 0.001). This effect was similar between groups (EF-MI and sleep: p = 0.327; EF-MI and organization-in-time: p = 0.230).

Sleep quality also significantly negatively affected organization-in-time (research group: β = −0.26, p = 0.012; control group: β = −0.31, p = 0.05), with similarly between the groups (p = 0.323). Note that the negative effects were because higher scores on the MSQ indicated poor sleep quality, whereas higher scores on the TOPS indicated better abilities. Significant negative effects were also found between organization-in-time abilities and emotional responses in both groups (research group: β = 0.56, p < 0.001; control group: β = 0.71, p < 0.001), with a stronger effect among participants in the control group (p = 0.016).

Discussion

This study describes the results of a secondary analysis based on data from three previous studies conducted in one laboratory. In all three studies, a research group of adults with NDD and a match control group without NDD were compared. The comparison included organization-in-time abilities of daily activities and their emotional consequences following decreased organization-in-time, as well as sensory, motor, EF, and sleep functions. The results highlight associations among these body functions and organization-in-time abilities with emotional consequences of daily disorganization-in-time.

This discussion relates first to the sample demographics and then to the study hypotheses, as defined in the Study Rationale and Aims section. As with previous results [21], the sample’s demographic characteristics show that significantly fewer adults with NDD than controls achieved academic education or reported a stable relationship with a spouse.

Additionally, as with previous results, we found significant between-group differences in organization-in-time abilities, sensory, motor, metacognitive EF (EF-MI), and sleep quality [4,7,21,28,29,43]. Significantly more participants in the research group than in the control group were defined as dealing with untypical sensory-processing patterns, decreased motor coordination and EF abilities, or low sleep quality. These results strengthen our previous results, this time with a larger sample, and broaden the existing literature by identifying characteristics of adults with NDD.

The literature describes some implications of these body functions related to daily activities and participation. Therefore, our results that more than a third of the participants in the group with NDD dealt with two or more decreased sensory/motor/EF/sleep functions emphasize the implications of comorbidity and the vast burden of NDD on people’s daily lives. Considering the possible implications for daily function, a more holistic picture of these functions must be gathered when planning evaluation and intervention methods for people with NDD.

Regarding the study hypotheses, overall, the results show that the predicted conceptual model describes interactions between sensory/motor/EF/sleep functions, organization-in-time, and emotional responses following disorganization-in-time. The model may be applied to both groups or each group separately. The model fits well using sensory processing and motor coordination to predict EF-MI and sleep quality, in turn predicting organization-in-time abilities and emotional responses following disorganization (Figure 3).

However, certain effects were unexpectedly stronger among the control group, including those between sensory processing and sleep quality, motor coordination and EF, sleep quality and organization-in-time, EF and organization-in-time, and organization-in-time and emotional responses. These unanticipated findings may be attributed to the self-reported nature of the questionnaires used in this study. Consistent with previous research [13], people with NDD may have difficulty accurately estimating their abilities compared to their actual performance. This discrepancy might explain the observed results. It is worth continuing to examine these findings and explanation in additional studies.

Organization-in-time and emotional consequences

In this secondary analysis, organization-in-time abilities predicted the participants’ emotional responses. Previous studies tied decreased organization-in-time abilities to negative emotional responses among adults with SLD [13] and ADHD [71]. Ferdous et al. [72] indicated that life balance is achieved not according to how many roles people have but how they organize their time within their tasks. For instance, students’ organization-in-time levels predicted their life participation, motivation, and enjoyment [73]. Unsuccessful organization-in-time could cause dysfunctional behaviours like being late to lessons or work, result in distress, and affect the person’s ability to regulate emotional responses [13].

Sensory processing

In both groups, sensory processing significantly correlated with EF-MI, motor coordination, and sleep quality. The relationship between sensory and motor functions is unsurprising. Sensory processing and motor abilities are interconnected aspects of human functioning since early development [74]. Recent studies reported that visual feedback increased the information available to the brain when generating complex, adaptive motor output among physically healthy adults [75] and described sensory functions and EF-MI as related [43,76]. Explaining those associations, Drigas and Mitsea [77] tied sensory awareness to inner and external stimuli and cognitive attentional processes. They suggested that capturing too many stimuli reduces attentional resources and slows sensory processing. If the sensory processing is efficient, it enables the mind to receive and process the sensory input according to the task or goals the person wishes to achieve. However, the results show that the sensory processing is more commonly inefficient among adults with NDD.

The finding of the significant relationships between sensory processing and sleep quality among adults with NDD broadens the limited literature about such relationships in this population [4, 21, 78]. As with the current findings, previous neurophysiologic studies claimed that people with insomnia are more aroused than are good sleepers because sensory hyperarousal decreases their ability to successfully filter external sensory information during sleep [79,80].

The results of the current data analysis identify sensory processing as a central mechanism interacting with body functions (particularly EF-MI and sleep quality) that significantly and directly affect the daily activities of people with NDD, as expressed in their organization-in-time abilities. Given their possibly crucial impact on participation in various life domains and on their emotional status [24], our findings suggest that sensory functions must be considered in evaluations and interventions of people with NDD.

Motor coordination

The results of this data analysis demonstrate a significant relationship between motor coordination and EF-MI among adults with NDD. Although the literature on adolescents and adults with DCD is limited, the few existing studies suggested that this population experiences difficulties performing EF-based daily tasks [e.g., 81]. These results indicate that the input adults with NDD receive from their sensory and motor systems contribute to decreased EF-MI and, thus, to decreased performance of daily tasks. Previous literature about the implications of deficient motor coordination on adults’ health-related quality of life [82] led to the need to consider this domain when evaluating adults with SLD and/or ADHD.

Executive functions

In both the research and control groups in this secondary data analysis, EF-MI significantly correlated with organization-in-time abilities. This finding stresses the meaning of efficient EF-MI among adults without NDD versus the inefficient EF-MI of adults with NDD and the effect of this difference on their daily challenges and emotional reactions. This finding emphasizes the need to relate to EF in evaluation and intervention processes among adults with NDD to increase their daily organizational abilities and, consequently, their quality of life [7].

Sleep quality

The SEM model revealed that sleep quality is also tied with organization-in-time abilities at the level of daily activities and participation, with a stronger relationship in the group with NDD. The existing literature on the implications of decreased sleep quality and quantity on adults’ work performance [4] supports the effects found in our study between organization-in-time abilities and sleep quality in both the research and control group. Increased sleep deprivation considerably affected information processing, reducing task performance [83].

Summary

The holistic picture presented in this study ties decreased organization-in-time and varied body functions to consequential emotional responses among adults with NDD (SLD and/or ADHD). Their daily experiences may cause negative emotions, and, presumably, negative environmental feedback may lead to more negative feelings. Such emotional and psychological factors add to the challenges that people with NDD may experience and may further affect their performance [51]. Negative daily experiences can have a high cost in frustration, self-concept, and self-esteem in multiple life domains, including home, work, social, and leisure environments [4,17].

Describing the results of this secondary data analysis in ICF terms [9], it appears that people with health conditions, such as NDD (SLD/ADHD), may experience decreased body functions, including sensory and motor functions, EF-MI, and sleep quality. These related sensory and motor body functions affect EF and sleep quality, disorganizing their body functions. The directly decreased EF-MI and sleep quality affect their activity levels, as reflected in decreased organization-in-time abilities and limited participation in various life domains. Due to a disorganization of time, adults with NDD may express extreme emotional responses. Previous literature suggested that, in the long run, these negative daily experiences may affect their emotional quality of life [7] and lead to additional health conditions, such as depression and anxiety [e.g., 4]. Depression and anxiety may result in activity limitations, decreased participation, and different life outcomes in adulthood [e.g., 17].

Limitations and future research

This study’s results were based on a secondary data analysis obtained through participants’ subjective self-reports. Future research should use additional objective measures and investigate the possible contributions to this model of additional ICF components, including other body functions and contextual/environmental factors.

Conclusions

The effects among the varied domains reveal intricate relationships between daily functional abilities, such as organization-in-time (classified under activity and participation) and the body functions of sensory, motor, EF-MI, and sleep functions. Our proposed model elucidates an axis of decreased emotional regulation and organization-in-time among adults with NDD, offering a comprehensive view of the interdependencies between these capabilities and overall daily functioning. Crucially, it highlights the emotional consequences of activity limitations, which, if occurring daily, may detrimentally affect emotional health and potentially lead to depression and anxiety [84,85]. Zisman-Ilani [86]. indicated that unrecognized personal differences causing mental deficiencies and the lack of early treatment can exacerbate symptoms, potentially leading to psychiatric conditions. Our study’s distinctiveness lies in its holistic approach, integrating emotional and functional dimensions to provide a clearer "big picture" of NDD.

Implications

This study underscores the need for early and precise evaluation and intervention for people with NDD to prevent secondary negative emotional effects, different life outcomes, and decreased quality of life. In so doing, it aims to inform clinical practices and therapeutic strategies, ensuring that interventions are comprehensive and tailored to address the neurodevelopmental, functional, and emotional aspects of NDD.

Disclosure statement

The authors report no conflicts of interest.

Data availability statement

The data that support the findings of this study are available on request from the corresponding author [SR]. The data are not publicly available because they contain information that could compromise the research participants’ privacy.

Additional information

Funding

This work was supported by the Israeli Ministry of Science and Technology (Grant no. 3-8634), by the National Insurance Institute of Israel (Grant No. 46006), and by the Israel Insurance Association.