Cognitive decline in normal aging and its prevention: a review on non-pharmacological lifestyle strategies

Figures & data

Figure 1 Flowchart of the selection procedure.

Table 1 Overview of the 12 selected studies focused on cognitive decline and its prevention by intervention activities

Author	Objective	Type of the intervention activity and its frequency	Intervention period	Number of subjects	Main outcome assessments	Main findings
Buchman et al^Citation19 (observational cohort study)	To verify a hypothesis that objective measure of total daily physical activity predicts incident AD and cognitive decline	Daily physical activities for 24 hours for 10 days	4 years	716 older subjects free of dementia. No control group	Structured annual clinical examination including a battery of 19 cognitive tests; actigraphy	People who do more physical activities per day have a lower risk of cognitive decline than those doing it only occasionally
Bugos et al^Citation11 (RCT)	To assess the efficacy of IPI on executive functioning and working memory in older healthy individuals	IPI: the intervention group had a 30-minute lesson per week and practiced for 3 hours a week at minimum	9 months	31 musically naïve seniors (60–85 years). Two randomly assigned groups: intervention group (16 subjects) and passive control group (15 subjects)	Neuropsychological assessments were administered at three time points: pre-training, following 6 months of intervention, and following a 3-month delay	Results of this study suggest that IPI may serve as an effective cognitive intervention for age-related cognitive decline
Colcombe et al^Citation20 (RCT)	To assess whether aerobic fitness training of older humans can increase brain volume in regions associated with age-related decline in both brain structure and cognition	Aerobic training in the intervention group; toning and stretching exercises in the active control group; three 1-hour exercises per week in both groups	6 months	59 healthy but sedentary community-dwelling volunteers, aged 60–79 years. 30 subjects in the intervention group and 29 in the active control group +20 younger passive controls	Magnetic resonance imaging; a graded exercise test on a motor-driven treadmill; peak oxygen uptake (VO2 peak) was measured from expired air samples taken at 30-second intervals until the highest VO2 peak was attained at the point of volitional exhaustion	The results show that the participation in an aerobic exercise program increased volume in both gray and white matter primarily located in prefrontal and temporal cortices in comparison with no effects in the active non-aerobic control group
Erickson et al^Citation21 (descriptive study)	To investigate whether individuals with higher levels of aerobic fitness display greater volume of the hippocampus and better spatial memory performance than individuals with lower fitness levels	Aerobic exercises	NA	165 nondemented older adults	In exploratory analyses, it was assessed whether hippocampal volume mediated the relationship between fitness and spatial memory; by using a region-of-interest analysis on magnetic resonance images a triple association such that higher fitness levels were associated with larger left and right hippocampi after controlling for age, sex, and years of education, and larger hippocampi and higher fitness levels were correlated with better spatial memory performance	The results indicate that higher levels of aerobic fitness are associated with increased hippocampal volume in older humans, which translates to better memory function
Martinez-Lapiscina et al^Citation22 (RCT)	To assess the effect on cognition of a controlled intervention testing MedDiet	MedDiet (supplemented with EVOO or mixed nuts) versus a low-fat control diet; participants allocated to the MedDiet groups received EVOO (1 L/week) or 30 g/day of mixed nuts	Clinical trial after 6.5 years of nutritional intervention	285 subjects, 44.8% men, 74.1±5.7 years; 95 randomly assigned to each of three groups	Evaluation by two neurologists blinded to group assignment after 6.5 years of nutritional intervention	Better post-trial cognitive performance versus control in all cognitive domains and significantly better performance across fluency and memory tasks were observed for participants allocated to the MedDiet + EVOO group
Miller et al^Citation23 (observational study)	To determine whether a 6-week educational program can lead to improved memory performance in older adults	Educational program on memory training, physical activity, stress reduction, and healthy diet; 60-minute classes held twice weekly with 15–20 participants per class	6 weeks	115 participants (mean age: 80.9 [SD: 6.0 years]); no control group	Objective cognitive measures evaluated changes in five domains: immediate verbal memory, delayed verbal memory, retention of verbal information, memory recognition, and verbal fluency. A standardized metamemory instrument assessed four domains of memory self-awareness: frequency and severity of forgetting, retrospective functioning, and mnemonics use	The findings indicate that a 6-week healthy lifestyle program can improve both encoding and recalling of new verbal information, as well as self-perception of memory ability in older adults residing in continuing care retirement communities
Murphy et al^Citation24 (RCT)	To evaluate the effect on PVF performance of a brief crossword-based intervention in a cognitively normal, community-based sample	The intervention group was doing a crossword on a daily basis; the control group was keeping a daily gratitude diary for the same period	4 weeks	37 older subjects divided randomly into the intervention and control group	2×2 mixed analyses of variance has been conducted	The results indicate that the crossword group performed significantly better over time than the control group in both total PVF score and in the cluster size component
Muscari et al^Citation25 (RCT)	To evaluate the effects of EET on the cognitive status of healthy community-dwelling older adults	The intervention group had a 12-month supervised EET in a community gym, 3 hours a week	12 months	120 healthy subjects aged 65–74 years; 60 subjects in the intervention group; 60 in the passive control group	Cognitive status was assessed by one single test (MMSE). Anthropometric indexes, routine laboratory measurements, and C-reactive protein were also assessed	The control group showed a significant decrease in MMSE score (mean difference −1.21, 95% CI −1.83/−0.60, P=0.0002), which differed significantly (P=0.02) from the intervention group scores (−0.21, 95% CI −0.79/0.37, P=0.47)
Sato et al^Citation26 (RCT)	To compare the effects of water-based exercise with and without cognitive stimuli on cognitive and physical functions	The exercise sessions were divided into two exercise series: a 10-minute series of land-based warm-up, consisting of flexibility exercises, and a 50-minute series of exercises in water. The Nor-WE consisted of 10 minutes of walking, 30 minutes of strength and stepping exercise, including stride over, and 10 minutes of stretching and relaxation in water. The Cog-WE consisted of 10 minutes of walking, 30 minutes of water-cognitive exercises, and 10 minutes of stretching and relaxation in water	10 weeks	21 older subjects were randomly divided into the intervention group and the active control group	Cognitive function, physical function, and ADL were measured before the exercise intervention (pre-intervention) and 10 weeks after the intervention (post-intervention)	The findings show that participation in the Cog-WE considerably improved attention, memory, and learning, and in the general cognitive, while participation in the Nor-WE dramatically improved walking ability and lower limb muscle strength. The results reveal that the benefits depend on the characteristics of each specific exercise program. These findings highlight the importance of prescription for personalized water-based exercises to elderly adults to improve cognitive function
Simoni et al^Citation27 (cross-sectional study)	To compare the effects of overground and treadmill gait on dual task performance in older healthy adults	Overground walking and treadmill walk	The treadmill testing was performed first, followed by overground testing between 1 and 2 weeks	29 healthy older adults (mean age 75 years, 14 females)	Gait kinematic parameters and cognitive performance were obtained in 29 healthy older adults when they were walking freely on a sensorized carpet or during treadmill walking with an optoelectronic system, in single task or dual task conditions, using alternate repetition of letters as a cognitive verbal task	Both motor and cognitive performances decline during dual task testing with overground walking, while cognitive performance remains unaffected in dual task testing on the treadmill. These findings suggest that treadmill walk does not involve brain areas susceptible to interference from the introduction of a cognitive task
Tai et al^Citation12 (RCT)	To identify the effect of music intervention on cognitive function and depression status of residents in senior citizen apartments	Buddhist hymns; the intervention group listened to the 30-minute Buddhist hymns using the Buddha machine alone twice a day (in the morning and before bedtime) from Monday to Friday for 4 months; they also took a note if they finished their daily music therapy	4 months	60 healthy seniors, aged 65+; 41 participated in the intervention music group and 19 in the passive comparison group	MMSE and the Geriatric Depression Scale-short form at the baseline, 1 month, and 4 months	Music intervention, specifically Buddhist hymns may delay cognitive decline and improve mood of older people
Valls-Pedret et al^Citation28 (RCT)	To investigate whether a MedDiet supplemented with antioxidant-rich foods influences cognitive function compared with a control diet	Participants were randomly assigned to MedDiet supplemented with EVOO (1 L/week), MedDiet supplemented with mixed nuts (30 g/day), or a control diet (advice to reduce dietary fat)	5 years	447 cognitively healthy volunteers (233 women [52.1%]; mean age, 66.9 years); three groups: two intervention groups and one control group	A neuropsychological test battery: MMSE, Rey Auditory Verbal Learning Test, Animals Semantic Fluency, Digit Span subtest from the Wechsler Adult Intelligence Scale, Verbal Paired Associates from the Wechsler Memory Scale, and the Color Trail Test	In an older population, a MedDiet supplemented with olive oil or nuts is associated with improved cognitive function

Abbreviations: AD, Alzheimer’s disease; ADL, activities of daily living; CI, confidence interval; EET, endurance exercise training; EVOO, extravirgin olive oil; IPI, individualized piano instruction; MedDiet, Mediterranean diet; MMSE, Mini Mental State Examination; NA, not available; PVF, phonemic verbal fluency; RCT, randomized controlled trial; SD, standard deviation.

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Martinez-LapiscinaEHClaveroPToledoEVirgin olive oil supplementation and long-term cognition: the PREDIMED-NAVARRA randomized, trialJ Nutr Health Aging201317654455223732551

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MurphyMO’SullivanKKelleherKGDaily crosswords improve verbal fluency: a brief intervention studyInt J Geriatr Psychiatry201429991591924493633

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MuscariAGiannoniCPierpaoliLChronic endurance exercise training prevents aging-related cognitive decline in healthy older adults: a randomized controlled trialInt J Geriatr Psychiatry201025101055106420033904

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SatoDSekoCHashitomiTSengokuYNomuraTDifferential effects of water-based exercise on the cognitive function in independent elderly adultsAging Clin Exp Res201527214915924965855

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SimoniDRubbieriGBacciniMDifferent motor tasks impact differently on cognitive performance of older persons during dual task testsClin Biomech (Bristol Avon)2013286692696

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TaiS-YWangL-CYangY-HEffect of music intervention on the cognitive and depression status of senior apartment residents in TaiwanNeuropsychiatr Dis Treat2015111449145426109859

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