Yoga Education Program for Improving Memory in Older Adults: A Multicity 5-Year Follow-Up Study

Abstract

This article reports a multicity study on the effect of a yoga education program (YEP) in improving memory and cognitive functions of a nonclinical sample of community-dwelling older adults. Specifically, the intervening personal resources that bolster or hinder YEP effectiveness were examined. Of the original cohort of 918 older adults randomized into intervention and waitlist control groups, 792 remained with the study 5 years later. Results indicated that weekly YEP lessons and self-practice improved participants’ scores on the Mini-Mental State Examination (MMSE) and Rivermead Behavioral Memory Test–Third Edition (RBMT-3). Participants from Asian cities, women, Hindus and Buddhists, middle class, highly educated, retired, ever single or widowed, living alone or with children and kin, were more responsive to the YEP. Regular attendance and self-practice were strong moderators of YEP effectiveness, with self-practice having the strongest predictor effect. Some cultural variations and improvisations would lend the YEP a wider application.

Keywords

yoga yoga education program memory older adults waitlist control design follow-up study

Introduction

Memory issues and cognitive decline are common among older adults. While the more serious conditions are those of Alzheimer’s disease and dementia, even healthy and nonclinical populations of older adults experience memory decline or loss of cognitive functions, specifically working memory, thereby being a population at considerable risk (Miyake & Friedman, 2012). Physical exercise and related forms of physical activity have been tested to prove useful in enabling memory functions (e.g., Ofei-Dodoo et al., 2018; Sandroff, Hillman, Benedict, & Motl, 2015). Aerobic training, fitness activities, walking exercise, and endurance training have been tested to have positive effects on increasing hippocampal volume in older adults (e.g., Ikudome et al., 2015).

Research in examining the efficacy of some new and more holistic techniques such as meditation, mindfulness, and yoga is also fast growing (Moss et al., 2015). Studies have shown that yoga has several benefits of physiological and psychological nature (Luu, 2016) and specifically so for older adults (Streeter et al., 2010). Yoga has been tested as useful for memory enhancement for older adults through clinical studies and randomized trials. For instance, McDougall, Vance, Wayne, Ford, and Ross (2015) tested the impact of adding yoga to an intervention designed to improve memory and cognitive performance of older adults from retirement communities in Central Texas. Their results indicated that adding yoga to the intervention led to significant gains in memory performance, instrumental activities of daily living, memory self-efficacy, and fewer depressive symptoms. Research has investigated different forms of yoga, such as Hatha yoga that focuses more on physical postures, and the effect on cognitive functions. Majority reports have revealed positive benefits in the domains of sustained attention, memory, and executive functions (e.g., Gothe, Kramer, & McAuley, 2014; Gothe & McAuley, 2015). Most of these studies have tested the cognitive effects of yoga on older adults, compared with a control group of seniors doing other forms of physical exercise, such as aerobics and walking, and found yoga to be more effective. In general, studies have shown post-yoga training improvements in various memory facets such as visuospatial processing, working memory, and cortical plasticity (e.g., Kozhevnikov, Louchakova, Josipovic, & Motes, 2009).

Research has also shown that the effectiveness of yoga training is dependent on cultural factors. For instance, Woods-Giscombé and Gaylord (2014) indicate that connecting such interventions to familiar cultural and spiritual practices of clients yield better results. Studies have shown that women are better yoga learners vis-à-vis men (e.g., Woods-Giscombé & Lobel, 2008); however, men display fewer distress symptoms and psychological disturbances, and hence are at a pretest advantage.

In general, the technique finds appreciation among educated and health-conscious middle class practitioners (Gothe et al., 2014; Telles, Bhardwaj, Kumar, Kumar, & Balkrishna, 2012). However, some studies have also shown that sustained yoga and mindfulness interventions with low-income older adults yield positive results (e.g., Palta et al., 2012; Szanton et al., 2011). Furthermore, studies have shown that participants of stable marital status and living arrangements perform better in yoga interventions vis-à-vis those who experience marital disruption (e.g., Hariprasad et al., 2013). Being ever single or widowed in old age is a positive moderator for increased and systematic focus on engagement with well-being enhancing technologies such as yoga (e.g., Klainin-Yobas, Oo, Suzanne Yew, & Lau, 2015), although more research evidence is needed to draw authoritative conclusions. One important moderator of yoga effectiveness, which is also its distinctiveness as a technique, is practitioners’ self-engagement with the technique (e.g., Ross & Thomas, 2010).

Hence, the distinctiveness of yoga is that the technique draws from and relies heavily on practitioners’ personal biographical and cultural resources and self-engagement. Theoretically, this can be explained through the biopsychosocial model that proposes the physical health benefits of yoga that could be similar to any form of exercise, but unlike more competitive physical endeavors, yoga helps quiet the body (Evans, Tsao, Sternlieb, & Zeltzer, 2009). Its distinguished feature lies in practitioners’ own engagement with the technique as its holistic focus involves self-efficacy, coping, and positive mood. This is combined with behavioral change, cognitive change, and a sense of connection to others. Self-engagement is emphasized through personal practice lessons or personal contemplative practice, being present to one’s immediate experience and reflecting on intentions, choices, and taking effective actions (Horovitz & Elgelid, 2015).

Present Study and Hypotheses

There is no research evidence on the effect of long-term sustained yoga practice on memory in community-dwelling older adults, as well as the intervening demographic and cultural factors that may bolster or deter yoga program impact. This article thus reports a multicity 5-year follow-up waitlist control design study examining the impact of a customized yoga education program (YEP) on memory and cognitive functions of a nonclinical population of older adults. Across four Asian and African cities (Mumbai city, Singapore, Pretoria, and Nairobi), the intervention cohort comprised 459 older adults at Phase 1 and 396 older adults at Phase 2, 5 years later. Two instruments were used to measure the outcomes at both the phases: the standard Mini-Mental State Examination (MMSE; Folstein, Folstein, & McHugh, 1975) and Rivermead Behavioral Memory Test–Third Edition (RBMT-3; Wilson et al., 2008).

Based on the literature, the following study hypotheses were developed:

Hypothesis 1: The YEP would be effective in enhancing memory and cognitive functions of the intervention cohort of older adults.

Hypothesis 2: The impact of the YEP on the intervention cohort would vary based on sociodemographic and biographical predictor variables (city, age, gender, religion, class, education, occupation, marital status, living arrangement, self-rated health, diet, general exercise regimen) and program-related moderators (lessons attended and self-practice).

Hypothesis 3: Self-practice would be the strongest predictor of the impact of the YEP on the outcome measures.

Method

Intervention and Comparison Group Profile

Table 1 depicts the profiles of the intervention and comparison group older adults. The intervention and comparison group were comparable on all basic sociodemographic characteristics.

Table 1.

Intervention and Comparison Group Profiles at Phases 1 and 2.

	Phase 1				Phase 2
	Intervention group		Comparison group		Intervention group		Comparison group
	N	%/M (SD)	N	%/M (SD)	N	%/M (SD)	N	%/M (SD)
City
Mumbai	133	28.98	133	28.98	113	28.53	113	28.53
Singapore city	124	27.01	124	27.01	109	27.53	109	27.53
Pretoria	104	22.66	104	22.66	92	23.23	92	23.23
Nairobi	98	21.35	98	21.35	82	20.71	82	20.71
Age	62.39 (3.87)		61.98 (3.08)		67.22 (3.32)		67.01 (3.11)
Gender
Men	216	47.06	209	45.53	203	51.26	195	49.24
Women	243	52.94	250	54.46	193	48.74	201	50.76
Religion
Christians	201	43.79	222	48.37	191	48.23	199	50.25
Hindu	163	35.31	143	31.15	140	35.35	128	32.32
Buddhist	55	11.98	65	14.16	42	10.61	51	12.88
Muslims	40	8.71	29	6.32	23	5.81	18	4.54
Class
Middle class	321	69.93	335	72.98	289	72.97	288	72.72
Elite	138	30.06	124	27.01	107	27.02	108	27.27
Education
Graduate	188	40.96	197	42.92	165	41.67	168	42.42
Postgraduate	203	44.23	202	44.01	183	46.21	181	45.71
Professional degree	68	14.81	60	13.07	48	12.12	47	11.87
Occupation
Employed	82	17.86	97	21.13	66	16.67	73	18.43
Retired	201	43.79	195	42.48	162	40.91	173	43.69
Homemakers	176	38.34	167	36.38	168	42.42	150	37.88
Marital status
Currently married	178	38.78	189	41.17	157	39.65	171	43.18
Never married	104	22.66	88	19.17	89	22.47	72	18.09
Widowed	131	28.54	126	27.45	118	29.80	107	26.88
Divorced	46	10.02	56	12.20	32	8.08	46	11.56
Living arrangement
Living alone	144	31.37	140	30.50	124	31.31	113	28.53
Living with spouse	178	38.78	189	41.17	157	39.65	171	43.18
With children and kin	117	25.49	110	23.96	98	24.75	95	23.99
Housing colonies for seniors	20	4.36	20	4.36	17	4.29	17	4.29
Self-rated health
Poor	52	11.33	69	15.03	18	4.54	16	4.04
Fair	249	54.25	208	45.31	128	32.32	113	28.53
Good	118	25.71	145	31.59	205	51.77	208	52.52
Very good	40	8.71	37	8.06	45	11.36	59	14.90
Dietary habits
Vegetarian	141	30.71	152	33.11	127	32.07	121	19.90
Vegan	49	10.67	58	12.64	38	9.59	42	10.61
Non-vegetarian	269	58.61	249	54.25	231	58.33	233	58.84
General exercise
Regular	135	28.78	148	32.24	261	65.91	104	26.26
Infrequent	298	64.92	288	62.74	135	34.09	254	64.14
No exercise	26	5.66	23	5.01	0	0.00	38	9.59
Total	459	100.00	459	100.00	396	100.00	396	100.00

Intervention and Comparison Group Recruitment

Intervention and comparison group recruitment was done stagewise. At the first stage, four community-based organizations working with older adults in the four cities (Mumbai, Singapore city, Pretoria, and Nairobi) were identified through networks. Functionaries helped reach out to a total of 918 of community-dwelling older adult members who had approached them for various services in the past and were willing to participate in a YEP experiment and study. This comprised a nonclinical sample, with no confirmed diagnosis of memory and cognitive decline as per the existing records of the community-based organizations. The researcher randomized intervention group participants using computer-generated random number tables, subsequent to which 459 older adults were allocated to the intervention group and an equal number to the waitlist control or comparison group at Phase 1 (year 2011) of the study. The randomization and experimental conditions were unmasked from the intervention and comparison group. Intervention group participants underwent the YEP and comparison group older adults did not undergo any specific intervention. At Phase 2, 5 years later, 396 older adult participants remained with the YEP and the study. Participant attrition was due to unwillingness to continue (23), death (17), relocation (11), and health issues and family responsibilities (12). An equal number of comparison group older adults from the original cohort were re-contacted for Phase 2 (year 2016). Hence, finally, data of 792 community-dwelling older adults across four cities were analyzed. Figure 1 illustrates the said details.

Figure 1.

Flow of participants through each stage of the experiment.

Measures

Pre- and posttest interviews were conducted with the intervention and comparison cohorts of older adults. The schedule comprised question on sociodemographic and biographical profiles of older adults (city, age, gender, religion, class, education, occupation, marital status, living arrangement, self-rated health, diet, general exercise regimen) and the outcome measures. Posttest data on number of YEP rounds attended and weekly self-practice as per diary records maintained by the instructor were collected. Two scales were administered: MMSE and RBMT-3. The Short form of the MMSE originally developed by Folstein et al. (1975) is a standard 30-point questionnaire intended to examine mental functions including orientation to time, orientation to place, registration, attention and calculation, recall, language, repetition and complex commands. It takes about 10 min to administer. Any score greater than or equal to 24 points (out of 30) indicates normal cognition. This was the corrected cut-off score after taking into account educational attainment and age (Crum, Anthony, Bassett, Folstein, & Bassett, 1993). Scores between 24 and 30 indicated no cognitive impairment, 18 and 23 indicated mild cognitive impairment, and 0 and 17 indicated severe cognitive impairment. Studies have validated MMSE in varied cultural contexts and with a cross-section of population groups (including clinical samples and older adults) and concluded acceptable psychometric properties including internal and external construct validity, reliability, and convergent validity (e.g., Dean, Feldman, Morere, & Morton, 2009; Tuijl, Scholte, de Craen, & van der Mast, 2012). For the present study, Cronbach’s α = .92, item-scale intercorrelation = .91, Pearson’s r = .89.

The RBMT-3 developed by Wilson et al. (2008) is an assessment that uses everyday memory tasks to determine gross memory functioning. RBMT-3 includes updated stories and a new novel task subset that assesses new learning. The RBMT-3 includes 14 subtests assessing aspects of visual, verbal, recall, recognition, immediate, and delayed everyday memory. In addition, prospective memory skills and the ability to learn new information are measured. It takes approximately 30 min to complete and retesting can be completed with Version 2 of the tool. The 14 subtests are as follows: (a) first and second names—delayed recall, (b) belongings—delayed recall, (c) appointments—delayed recall, (d) story—immediate recall, (e) story—delayed recall, (f) picture recognition—delayed recall, (g) face recognition—delayed recall, (h) route—immediate recall, (i) route—delayed recall, (j) message—immediate recall, (k) message—delayed recall, (l) orientation—responding to questions relating to person, time and place, (m) novel task—immediate recall (examinee uses different colored pieces to make a shape as demonstrated by the examiner), and (n) novel task—delayed recall (examinee uses different colored pieces to make the same shape at a later time in the testing session, this time without demonstration from the examiner). Raw summative scores on all the 14 RBMT-3 subtests are converted to subtest scaled scores with a mean of 10 and standard deviation of 3. Percentile ranks for scaled scores are available in the kit and subtests take into account an individual’s age. A General Memory Index (GMI) representing the overall memory performance is also available. The index is standardized to have a mean of 100 and standard deviation of 15. GMI scores are calculated by summing scaled scores on the RBMT-3 subtests and then converting this sum to a GMI using appropriate conversion table that also report confidence intervals and percentile ranks for each GMI. Few previously published studies have validated the RBMT-3 in different cultural contexts (such as Ireland and Hong Kong) as well as with cross-section of population groups (such as older adults with or without cognitive and memory impairments), and concluded acceptable psychometric properties including internal and external construct validity, reliability, and convergent validity (e.g., Fong et al., 2017; Hynes & Shiel, 2014). For the present study, Version 1 was used in the pretest phase and Version 2 was used in the posttest phase for the individual to avoid repetition. Scaled subtest scores and standardized GMI were used for scoring. For this investigation, range of validity-reliability measures for the 14 subtests and GMI were as follows: Cronbach’s α = .83-.92, item-subscale intercorrelation = .88-.93, and Pearson’s r = .92-.94. The schedule and scales were administered in English language.

YEP Details

YEP development

The YEP was developed by yoga experts associated with a yoga training institute headquartered in Mumbai and having intercountry branches run by certified yoga trainers. Four meetings were held to develop a customized yoga program aimed at memory and cognitive enhancement. The deliberations were recorded and, subsequently, the YEP was finalized and vetted by experts. To implement the YEP, experts recommended yoga trainers based in these respective cities. A master class was organized to train the trainers on this customized program. The Google-group was then a platform to share and provide refresher inputs.

YEP details

The YEP was organized once a week as a 40-min lesson for a period of 5 years. Attending 75% of the lessons was a prerequisite to retain participant status in the study. The key features of the YEP were postures interspersed with relaxation, slow movements, and inner watchful awareness.

The repertoire of a single round of lessons was as follows: (a) prayer or simple silence (3 min), (b) instant relaxation technique (IRT) in supine position with isometric contraction of the muscles (3 min), (c) tree posture (i.e., standing still) and centering in tree posture (3 min), (d) half wheel posture with one arm raised and body tilted to the other side and centering therein and repeating the same with the other arm (3 min), (e) forward bending posture and backward bending posture (3 min), (f) yoga posture—Sun salutation posture or Surya Namaskara (10 min), (g) two other yoga postures from the selection of 10 yoga postures for older adults—(10 min), and (h) deep relaxation technique (DRT) in supine position (5 min).

The two different yoga postures per lesson that were identified based on moderate difficulty levels for the intervention cohort were as follows: (a) lotus posture or padma-asana, (b) diamond posture or vajra-asana, (c) wheel posture or chakra-asana, (d) bow posture or dhanur-asana, (e) salutation pose or anjanaya-asana, (f) half-moon pose or ardhachandra-asana, (g) half-spinal twist pose or ardha-matsyendra-asana, (h) eagle pose or garuda-asana, (i) cow-face pose or gomukha-asana, and (j) plow pose or hala-asana.

A routine set of instructions was given for conducting the sessions as per the regular yoga training. A yoga mattress and loose and comfortable clothing were the basic requirements. At the end of each lesson and round, self-practice was emphasized. Participants were asked to practice the lesson by themselves at least once and the same was recorded in a notebook maintained by the trainer in the subsequent week. Yoga education was aimed at centering, breath control, and personal perfection of every aspect of the learning.

Deliverer

Four yoga trainers based in the four cities delivered the YEP. Another four trainers served as back-up support in each of the four cities. The profile of yoga trainers was as follows: age (M = 38.94, SD = 6.82), gender (women = 6, men = 2), education (3 = postgraduates, 5 = graduates), occupation (2 = paid service/employment and part-time yoga trainers, 6 = homemakers and full-time yoga trainers), religion (6 = Hindus, 1 = Christian, 1 = Buddhist), and all trainers belonged to the middle class. All the yoga trainers had undergone the basic, advanced, and training-of-trainers courses of the yoga institute.

Procedure

Four yoga trainers conducted the weekly lessons in designated premises in the four cities with batches of intervention group participants. Four additional trainers were back-up support members throughout the study, to step-in as and when required. The customized YEP was delivered to older adults in weekly batches: M batch size = 32.56, SD = 3.04. Pretest data were collected by the researcher in each of the four cities prior to YEP commencement. A single interview comprising basic background details, MMSE and RBMT-3 took approximately 45 min. Posttest data were collected after a 5-year period. Data were collected at both the phases on tablets and then transferred to the mainframe computer. Yoga trainers and participants were offered Amazon gift vouchers at the end of the study.

Statistical Methods

Pre- and posttest scores of the intervention and comparison group older adults were analyzed through one-way ANOVA and compared using t tests. The effect sizes were examined through Cohen’s d statistics. Scheffe’s post hoc analyses criterion was used to examine the significant independent predictors of the dependent outcomes.

Posttest scores of the participants were further analyzed through MANOVA. Kruskal–Wallis nonparametric testing, Bonferroni’s adjusted alpha levels, and Pillai’s trace statistics were used to examine the independent, pairwise and combined effects of independent predictors and program-related moderator variables on the outcome measures. Two five-step hierarchical regression models were developed to examine the strongest predictor of the posttest MMSE and RBMT-3 (scaled subtest scores and standardized GMI) outcome measure scores of the participants.

Results

Primary analyses comprise 459 older adults in the intervention and comparison groups in the pretest phase and 396 older adults in the respective cohorts in the posttest phase. The YEP was delivered as intended in terms of lessons once a week for 5 years (average number of citywide lessons held in 5 years = 250.23, SD = 3.98). Self-practice was an integral component of the program to be done by participants once a week and recorded by yoga trainers on a weekly basis. Figure 1 depicts the participant flow through each stage of the experiment and the participation details. The intent-to-treat analyses present the pre- and posttest outcome measure scores, comparison, and important predictors and moderators of posttest scores of the participants.

MMSE and RBMT-3 Scores

Comparison group pretest

The average pretest MMSE score of the comparison group older adults was 24.30 (2.09). The average pretest scaled scores on the 14 RBMT-3 subtests and GMI (standardized) of the comparison group older adults were in the low average range and lower percentile rank, respectively. The effects of education, occupation, marital status, and living arrangement were significant. Post hoc analyses using Scheffe’s post hoc criterion for significance indicated that the pretest MMSE and RBMT-3 scores were higher for comparison group older adults with postgraduate and professional qualifications, in service or retired, single (never married, widowed, or divorced), and living alone or with children and kin.

Comparison group posttest

The average posttest MMSE score of the comparison group older adults was 24.11 (2.81). The average posttest scaled scores on the 14 RBMT-3 subtests and GMI (standardized) of the comparison group older adults were in the low average range and lower percentile rank, respectively. The effects of education, marital status, and living arrangement were significant. Post hoc analyses using Scheffe’s post hoc criterion for significance indicated that the posttest MMSE and RBMT-3 scores were higher for comparison group older adults with postgraduate and professional qualifications, single (never married, widowed, or divorced), and living alone or with children and kin.

Intervention group pretest

The average pretest MMSE score of the intervention group older adults was 24.59 (SD = 2.13). The average pretest scaled scores on the 14 RBMT-3 subtests and GMI (standardized) of the intervention group older adults were in the low average range and lower percentile, respectively. The effects of education, class, marital status, and living arrangement were significant. Post hoc analyses using Scheffe’s post hoc criterion for significance indicated that the pretest MMSE and RBMT-3 scores were higher for intervention group older adults with postgraduate and professional qualifications, middle class, single (never married, widowed, or divorced), and living alone or with children and kin.

Intervention group posttest

The average posttest MMSE score of the intervention group older adults was 28.91 (SD = 1.09). The average posttest scaled scores on the 14 RBMT-3 subtests and GMI (standardized) of the intervention group older adults were in the above average range and percentile, respectively. The effects of city, gender, religion, class, education, occupation, marital status, living arrangement, YEP lessons attended, and self-practice were significant. Post hoc analyses using Scheffe’s post hoc criterion for significance indicated that within the intervention cohort, the posttest MMSE and RBMT-3 scores were higher for older adults from Asian cities (Mumbai and Singapore city), women, Hindus and Buddhists, middle class, with postgraduate and professional qualifications, retired, single (never married, widowed, or divorced), living alone or with children and kin, who attended more than 75% of the YEP lessons, and regularly self-practiced.

Effect of YEP on MMSE and RBMT-3 Scores

Table 2 presents the pre- and posttest scores of the intervention and comparison group older adults on the MMSE and RBMT-3 outcome measures. The t tests and Cohen’s d statistics indicate that the intervention and comparison group cohorts’ outcome measure scores were equal at baseline. There was no significant difference in the posttest scores of the comparison group. The posttest MMSE and RBMT-3 scores of the intervention group participants were significantly higher than their own pretest scores and the posttest scores of the comparison group.

Table 2.

Pre- and Posttest RBMT-3 Scores of Intervention and Comparison Group.

	Comparison group				Intervention group				Comparison and intervention group pretest^a			Comparison group pre- and posttest^b			Comparison and intervention group posttest^c			Intervention group pre- and posttest^d
	Pretest		Posttest		Pretest		Posttest		Comparison and intervention group pretest^a			Comparison group pre- and posttest^b			Comparison and intervention group posttest^c			Intervention group pre- and posttest^d
	M	SD	M	SD	M	SD	M	SD	t	p	d	t	p	d	t	p	d	t	p	d
MMSE	24.30	2.09	24.11	2.81	24.59	2.13	28.91	1.09	46.77	.19	.16	51.28	.15	.18	33.48	.04	.43	29.81	.02	.46
RBMT-3^e
First and second names—delayed recall	6.06	0.93	6.11	0.88	6.09	0.79	8.88	0.92	42.39	.13	.17	31.61	.12	.19	11.38	.03	.41	12.11	.01	.46
Belongings—delayed recall	5.02	0.81	5.04	0.93	5.11	0.88	13.83	0.96	43.18	.14	.18	36.01	.16	.17	18.88	.03	.48	11.39	.00	.48
Appointments—delayed recall	6.93	.78	5.01	0.87	6.88	0.83	11.96	0.83	49.08	.16	.14	38.99	.15	.14	28.32	.03	.41	16.32	.00	.49
Story—immediate recall	5.82	0.77	5.63	0.82	5.09	0.85	13.83	0.91	45.81	.18	.17	38.92	.16	.13	26.97	.02	.38	18.91	.00	.48
Story—delayed recall	6.92	1.03	6.98	1.34	6.98	1.28	12.08	1.83	43.71	.13	.16	39.83	.12	.16	28.93	.02	.41	22.36	.00	.49
Picture recognition—delayed recall	5.03	1.98	5.34	1.96	5.28	1.18	12.86	1.02	48.92	.14	.18	38.77	.11	.16	29.08	.03	.45	18.03	.00	.49
Face recognition—delayed recall	6.89	0.78	6.88	0.85	6.96	0.83	11.91	1.13	51.31	.16	.16	43.98	.12	.16	28.96	.03	.46	19.71	.00	.48
Route—immediate recall	6.83	0.73	6.87	0.84	6.99	0.74	14.03	1.23	46.77	.17	.18	39.86	.13	.17	29.81	.02	.48	28.93	.01	.46
Route—delayed recall	6.86	0.88	6.92	0.83	5.01	1.32	13.08	1.98	41.81	.16	.17	40.88	.14	.17	29.81	.03	.47	30.02	.00	.49
Message—immediate recall	6.92	1.01	6.98	1.11	6.87	1.48	14.51	2.03	56.29	.17	.18	52.38	.15	.16	28.93	.02	.48	22.34	.00	.49
Message—delayed recall	7.01	2.33	7.32	2.03	7.03	2.01	14.51	2.11	58.71	.18	.19	56.09	.17	.16	29.03	.02	.48	21.39	.00	.49
Orientation	6.88	1.07	6.93	1.08	6.89	1.04	12.34	2.04	61.08	.19	.16	60.23	.18	.15	29.34	.02	.46	23.88	.00	.48
Novel task—immediate recall	6.68	0.88	6.83	0.92	7.08	1.13	13.08	2.01	49.82	.18	.17	50.41	.18	.14	28.93	.03	.47	21.38	.00	.49
Novel task—delayed recall	6.04	1.02	6.05	1.13	7.03	1.08	13.41	2.33	48.66	.18	.16	50.21	.12	.18	32.06	.04	.49	22.99	.00	.53
GMI (standardized)	86.32	12.03	85.71	11.38	86.14	11.45	148.98	14.38	78.91	.11	.19	86.48	.11	.20	48.93	.02	.51	31.86	.00	.57

Note. RBMT-3 = Rivermead Behavioral Memory Test–Third Edition; MMSE = Mini-Mental State Examination; GMI = General Memory Index.

df = 458.

df = 853.

df = 395.

df = 853.

Scaled subtest scores and standardized GMI.

Predictors and Moderators of Posttest MMSE and RBMT-3 Scores of Intervention Group Participants

The posttest MMSE and RBMT-3 scores of the intervention group participants were further subjected to a MANOVA with 10 moderators: city, gender, religion, class, education, occupation, marital status, living arrangement, rounds of YEP attended, and self-practice. Significant effects of predictors on outcomes were further examined through nonparametric testing (Kruskal–Wallis). All the moderator variables independently influenced the dependent outcomes. The pairwise effects or interactions of the following moderators were further significant: city, gender, religion, class, education, occupation, marital status, living arrangement, rounds of YEP attended, and self-practice (Roy’s largest root range = .077329-.099022), p = .01, $η_{p}^{2}$ range = .61-.74).

The pairwise effects of the two program-related moderators, rounds of YEP attended and self-practice, Roy’s largest root = .098213, F(3, 392) = 53.48, p = .01, $η_{p}^{2}$ = .62, were significant. Tests were further conducted using Bonferroni’s adjusted alpha levels of .005 (.05/10) per test. The independent, pairwise and interaction, and combined effects of all significant predictors and moderators on outcomes were significant. The posttest MMSE and RBMT-3 scores of the intervention group participants were higher under all the more significant independent predictors and moderators combined (i.e., for participants from Asian cities, women, Hindus and Buddhists, middle class, postgraduates or professionally qualified, retired, single [never married, widowed, divorced], living alone or with children and kin, having attended more than 75% of the YEP lessons, and having regularly self-practiced) vis-à-vis under less significant independent predictors and moderators combined (i.e., for participants from African cities, men, Christians and Muslims, elite, graduates, homemakers, currently married, living with spouse or in institutions, having attended less than 75% of the lessons and infrequently self-practicing). Table 3 depicts the significant multivariate effects.

Table 3.

Significant Multivariate Effects on Posttest Outcomes.

Variable(s)	Pillai’s trace	F	df	Error df
City	.109	34.18	3	394
Gender	.121	43.88	1	394
Religion	.132	44.29	3	394
Class	.108	39.87	1	394
Education	.133	52.39	2	394
Occupation	.201	62.84	3	394
Marital status	.167	78.02	3	394
Living arrangement	.181	63.88	3	394
Rounds of YEP Attended	.129	53.02	3	394
Self-Practice	.113	42.38	1	394
City × Rounds of YEP Attended	.204	56.08	9	392
City × Self-Practice	.213	62.09	3	392
Gender × Rounds of YEP Attended	.117	44.87	3	392
Gender × Self-Practice	.329	49.34	1	392
Religion × Rounds of YEP Attended	.106	53.28	9	392
Religion × Self-Practice	.221	60.81	3	392
Class × Rounds of YEP Attended	.208	56.34	3	392
Class × Self-Practice	.223	48.92	3	392
Education × Rounds of YEP Attended	.107	53.98	9	392
Education × Self-Practice	.114	49.88	3	392
Occupation × Rounds of YEP Attended	.181	52.39	9	392
Occupation × Self-Practice	.193	61.24	3	392
Marital Status × Rounds of YEP Attended	.221	33.89	9	392
Marital Status × Self-Practice	.206	71.28	3	392
Living Arrangement × Rounds of YEP Attended	.322	48.92	9	392
Living Arrangement × Self-Practice	.262	46.77	3	392
Rounds of YEP Attended × Self-Practice	.303	53.48	3	392
City × Gender × Religion × Class × Education × Occupation × Marital status × Living Arrangement × Rounds of YEP Attended × Self-Practice	.402	61.28	9	386

Note. YEP = yoga education program.

Tables 4 and 5 depict the five-step hierarchical regression model of the posttest MMSE and RBMT-3 scores of the intervention group participants. Table 4 depicts that when all the 10 variables were entered at Step 5 of the model, self-practice emerged as the strongest predictor uniquely explaining 16.1% variation in the posttest MMSE scores. Together all the 10 predictor and moderator variables explained 71.3% variation in the posttest MMSE scores of the participants. Table 5 depicts that when all the 10 variables were entered at Step 5 of the model, self-practice emerged as the strongest predictor uniquely explaining 16.2% variation in the posttest RBMT-3 scores of the participants. Together all the 10 predictor and moderator variables explained 73.3% variation in the posttest RBMT-3 scores of the participants.

Table 4.

Summary of Hierarchical Regression Analysis for Variables Predicting Posttest MMSE Scores of the Intervention Group (N = 396).

Variable	β	t	sr²	R	R ²	ΔR²
Step 1				.21	.04	.04
City	.23	2.04*	.03
Step 2				.31	.43	.14
City	.22	1.89*	.04
Gender	.18	2.01**	.04
Religion	.09	1.98**	.06
Class	.17	2.31***	.08
Step 3				.44	.56	.18
City	.23	1.31**	.05
Gender	.19	1.83**	.06
Religion	.21	1.68**	.04
Class	.15	2.03***	.04
Education	.28	1.49**	.07
Occupation	.09	2.01**	.06
Marital status	.12	1.78***	.05
Step 4				.58	.49	.19
City	.12	0.98*	.06
Gender	.08	1.04**	.07
Religion	.11	1.21**	.04
Class	.13	1.44***	.09
Education	.09	1.16**	.13
Occupation	.08	1.04*	.12
Marital status	.09	1.28**	.05
Living arrangement	.08	1.76**	.04
YEP lessons attended	.14	2.48***	.05
Step 5				.64	.53	.16
City	.08	0.56*	.05
Gender	.06	0.98**	.04
Religion	.12	1.01***	.03
Class	.09	1.14**	.04
Education	.15	1.01**	.03
Occupation	.13	0.88**	.07
Marital status	.11	0.96**	.08
Living arrangement	.05	1.03**	.07
YEP lessons attended	.16	2.02***	.04
Self-practice	.18	3.44	.11

Note. MMSE = Mini-Mental State Examination; YEP = yoga education program.

p = .05. **p = .01. ***p = .001.

Table 5.

Summary of Hierarchical Regression Analysis for Variables Predicting Posttest RBMT-3 Scores of the Intervention Group (N = 396).

Variable	β	t	sr²	R	R ²	ΔR²
Step 1				.05	.27	.04
City	.12	2.02*	.04
Step 2				.22	.38	.13
City	.13	1.88*	.05
Gender	.09	2.01**	.06
Religion	.11	2.13**	.06
Class	.16	1.86***	.07
Step 3				.34	.43	.23
City	.09	1.36**	.05
Gender	.12	1.75**	.06
Religion	.13	2.01***	.08
Class	.09	1.57**	.04
Education	.09	2.23***	.06
Occupation	.14	2.46***	.08
Marital status	.09	2.53**	.06
Step 4				.44	.52	.17
City	.16	1.22**	.04
Gender	.07	1.33**	.06
Religion	.11	1.88**	.09
Class	.09	1.23***	.08
Education	.12	2.04***	.06
Occupation	.11	2.18***	.07
Marital status	.08	2.19***	.06
Living arrangement	.05	2.78**	.04
YEP lessons attended	.07	2.89***	.04
Step 5				.56	.64	.16
City	.11	0.94*	.03
Gender	.08	1.06**	.04
Religion	.09	1.38**	.05
Class	.06	1.07**	.04
Education	.07	1.85**	.06
Occupation	.09	1.69***	.05
Marital status	.07	1.88**	.06
Living arrangement	.08	2.29*	.05
YEP lessons attended	.06	2.45***	.04
Self-practice	.08	3.06***	.09

Note. RBMT-3 = Rivermead Behavioral Memory Test–Third edition; YEP = yoga education program.

p = .05. **p = .01. ***p = .001.

Discussion and Conclusion

Results support the initial hypotheses. The YEP was effective in enhancing memory and cognitive functions of the intervention cohort of older adults. The impact of the YEP on the intervention cohort varied based on certain sociodemographic and biographical predictor variables and program-related moderators (lessons attended and self-practice).

Self-practice was the strongest predictor of the impact of the YEP on the outcome measures. The MMSE and RBMT-3 scores (14 subtests and standardized GMI scores) of the intervention and comparison cohorts were equal at baseline. Given the education status, the pretest MMSE scores of the intervention group participants and comparison group were in the borderline normal range. The scaled scores on the 14 RBMT-3 subtests and GMI were in the low average range and lower percentile rank, respectively. Within the comparison cohort, at the pretest phase, MMSE and RBMT-3 scores were higher for older adults with postgraduate and professional qualifications, in service or retired, single (never married, widowed or divorced), and living alone or with children and kin. This was also so for comparison as well as intervention cohorts at the posttest phase.

The t tests and Cohen’s d statistics indicated that there was no significant difference in the posttest scores of the comparison group. The posttest MMSE and RBMT-3 scores of the intervention group participants were significantly higher than their own pretest scores as well as the posttest scores of the comparison group. Hence, the YEP was effective in raising MMSE scores of intervention group participants to the acceptable range (>24) confirming no cognitive impairment. The posttest scaled scores of the intervention group participants on the 14 RBMT-3 subtests and standardized GMI were in the above average range (148.98 ± 14.38) and percentile, respectively, thereby indicating good gross memory functioning and sound visual, verbal, recall, recognition, immediate, and delayed everyday memory. This also indicated good prospective memory skills and the ability to learn new information. This substantiates the first hypothesis and thus establishes the effectiveness of YEP in improving memory of older adults.

Post hoc analyses and MANOVA indicated that the YEP was more effective for older adult participants from Asian cities (Mumbai and Singapore city), women, Hindus and Buddhists, middle class, with postgraduate and professional qualifications, retired, single (never married, widowed and divorced), living alone or with children and kin, who attended more than 75% of the YEP lessons, and regularly self-practiced. This supports the second study hypothesis that the YEP’s efficacy would vary based on participants’ sociodemographic and biographical profile variables (independent predictors such as city, gender, religion, class, education, occupation, marital status, and living arrangements) and program-related moderators (lessons attended and self-practice). The combination of pairs and clusters of significant independent predictors and moderators had a more robust impact on outcome measures. The two hierarchical regression models confirmed that self-practice was the strongest predictor of YEP effectiveness, thereby supporting the third hypothesis.

Overall, the results establish the effectiveness of YEP in enhancing memory functions and preventing cognitive decline in a cohort of community-dwelling nonclinical sample of older adults. Independent predictor and moderator-related variations in YEP affect substantiate and corroborate claims of some previous research. Intervention group participants from Asian cities, Hindus, and Buddhists were more responsive to the YEP than their African counterparts. This is similar to Woods-Giscombé and Gaylord’s (2014) study that highlights the importance of culture in relating to such programs. Since yoga is more familiar among Asian older adults as well as Hindus and Buddhists, to make the technique more effective for African seniors, Muslims, and Christians, adding familiar cultural and spiritual components to the YEP (such as culturally relevant affirmations during relaxation and breath focus) may add value. Older adult women, the more educated, and middle class participants were better learners and practitioners of YEP and gained more thereof (e.g., Gothe et al., 2014; Telles et al., 2012; Woods-Giscombé & Lobel, 2008). This draws attention to the fact that YEP needs further intensive components and improvisations for men, affluent class seniors, and the less qualified. Results of this study indicated that participants who were homemakers and/or presently employed were less serious students of the YEP vis-à-vis the retired. This may mean that whereas for the retired adults, the YEP was possibly a space-filling activity, for those employed or homemakers, the program may need some more innovations or participation incentives (such as alteration in geographical location or scheduling of lessons and flexible self-practice routines). Intervention group participants’ marital status and living arrangements were critical indicators of YEP effectiveness. Single participants and those living alone or with children and kin were more earnest participants and hence more responsive to the YEP. This unencumbered status, with either minimal (solitary) or some (children and kin) daily living companions, was a booster to engage in the YEP (e.g., Klainin-Yobas et al., 2015). Finally, results support that the YEP is a self-motivated individual practice contingent on intervention group participants’ propensity to engage and self-discipline.

The study has some of the following limitations. The control group underwent no intervention; therefore, any effect of the yoga program may be attributed to general physical activity rather than to yoga. Further research needs to incorporate control activities (other forms of physical exercise such as aerobics and walking). Pre- and posttest data were collected at two specific phases that do not capture the interim and iterative effects of the program. Hence, follow-up/re-assessment at more closer and regular periods would be required to examine changes in memory and cognitive functions attributable to YEP. Moreover, practice was measured via participant self-report of the same to the trainer on a weekly basis, then recorded in a diary, which is a limitation. Participant self-reported measurements like these, particularly, are susceptible to biased reporting and at-home practice might also be confounded by other factors, such as conscientiousness. Furthermore, qualitative narratives would add considerable value, as participants’ experiences with the YEP and related improvements in memory functions would provide newer insights. Some other intervening variables such as significant life course events, spousal variables, caregiving roles and responsibilities, and health conditions and alterations that may affect YEP participation and response also need to be taken into account in further research. Moreover, both the instruments used in the present study—MMSE and RBMT-3, are indicative and not conclusive, in that, lower scores indicate the need for further assessment and are in no way definite markers of cognitive impairment. However, since the study was with a nonclinical sample of community-dwelling older adults, the said scales were appropriate owing to their wide, cross-sectional, and cross-cultural applicability.

The YEP would be effective in enhancing memory and cognitive functions of a cross-section of community-dwelling older adults. Certain cultural variations would be required for participants from African contexts, Muslims, and Christians. Variations may include adding familiar spiritual ideology and cultural practices, supplementing the sessions with reading material, increasing communication (instructor availability), and having instructors from similar cultural backgrounds. YEP components may need to be improvised or intensified for older men, affluent seniors, currently married, and in poor health. Effectiveness of the YEP would be contingent on participants’ self-engagement and self-discipline, that needs to be emphasized.

Footnotes

Consent and Ethics

Informed consent was sought from all the participant and the comparison group members. There is no registered funder to report for this submission. Acknowledgements are due to all the functionaries of the community-based organizations and the yoga trainers for helping with the study. Acknowledgements are also due to all the participant and comparison group older adults. The yoga education program was developed and vetted by the Yoga Research Institute, Mumbai, India, for soundness of content, repertoire, and mode of delivery. The study has the approval of the independent research ethics committee of the University of Mumbai, India, and conforms to the norms provided in the Declaration of Helsinki, 1975, as revised in 2000. There are no conflicts of interests to report for this submission.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

References

Crum

Anthony

Bassett

Folstein

Bassett

(1993). Population-based norms for the Mini-Mental State Examination by age and educational level. Journal of the American Medical Association, 269, 2386-2391.

Dean

Feldman

Morere

Morton

(2009). Clinical evaluation of the mini-mental state exam with culturally deaf senior citizens. Archives in Clinical Neuropsychology, 24, 753-760.

Evans

Tsao

J. C. I.

Sternlieb

Zeltzer

L. K.

(2009). Using the biopsychosocial model to understand the health benefits of yoga. Journal of Complementary and Integrative Medicine, 6(1), 1-22.

Folstein

McHugh

(1975). “Mini-mental state”: A practical method for grading the cognitive state of patients for the clinician. Journal of Psychiatric Research, 12, 189-198.

Fong

Lee

Tsang

Wan

Zhang

Lau

(2019). The clinical utility, reliability and validity of the Rivermead Behavioural Memory Test-Third Edition (RBMT-3) in Hong Kong older adults with or without cognitive impairments. Neuropsychology Rehabilitation, 29(1), 144-159.

Gothe

N. P.

Kramer

A. F.

McAuley

(2014). The effects of an 8-week Hatha yoga intervention on executive function in older adults. The Journals of Gerontology Series A: Biological Sciences & Medical Sciences, 69, 1109-1116.

Gothe

N. P.

McAuley

(2015). Yoga and cognition: A meta-analysis of chronic and acute effects. Psychosomatic Medicine, 77, 784-797.

Hariprasad

Koparde

Sivakumar

Varambally

Thirthalli

Varghese

Gangadhar

(2013). Randomized clinical trial of yoga-based intervention in residents from elderly homes: Effects on cognitive function. Indian Journal of Psychiatry, 55, S357-S363.

Horovitz

Elgelid

(2015). Yoga therapy: Theory and practice. New York, NY: Routledge.

10.

Hynes

Shiel

(2014). Validating an Irish-language version of the Rivermead Behavioural Memory Test—Second edition. The British Journal of Occupational Therapy, 77, 198-204.

11.

Ikudome

Mori

Unenaka

Kawanishi

Kitamura

Nakamoto

(2015). Effect of long-term body-mass-based resistance exercise on cognitive function in elderly people. Journal of Applied Gerontology, 36, 1519-1533.

12.

Klainin-Yobas

W. N.

Suzanne Yew

P. Y.

Lau

(2015). Effects of relaxation interventions on depression and anxiety among older adults: A systematic review. Aging & Mental Health, 19, 1043-1055.

13.

Kozhevnikov

Louchakova

Josipovic

Motes

M. A.

(2009). The enhancement of visuospatial processing efficiency through Buddhist deity meditation. Psychological Science, 20, 645-653.

14.

Luu

(2016). Comparing the acute effects of hatha yoga and meditation on executive function (Doctoral thesis). University of Waterloo, Ontario, Canada.

15.

McDougall

Vance

Wayne

Ford

Ross

(2015). Memory training plus for older adults. Journal of Neuroscience and Nursing, 47, 178-188.

16.

Miyake

Friedman

N. P.

(2012). The nature and organization of individual differences in executive functions four general conclusions. Current Directions in Psychological Science, 21, 8-14.

17.

Moss

Reibel

Greeson

Thapar

Bubb

Salmon

Newberg

(2015). An adapted mindfulness-based stress reduction program for elders in a continuing care retirement community: Quantitative and qualitative results from a pilot randomized controlled trial. Journal of Applied Gerontology, 34, 518-538.

18.

Ofei-Dodoo

Rogers

Morgan

Amini

Takeshima

Rogers

(2018). The impact of an active lifestyle on the functional fitness level of older women. Journal of Gerontological Social Work, 37, 687-705.

19.

Palta

Page

Piferi

Gill

Hayat

Connolly

Szanton

(2012). Evaluation of a mindfulness-based intervention program to decrease blood pressure in low-income African American older adults. Journal of Urban Health, 89, 308-316.

20.

Ross

Thomas

(2010). The health benefits of yoga and exercise: A review of comparison studies. Journal of Alternative and Complementary Medicine, 16, 3-12.

21.

Sandroff

B. M.

Hillman

C. H.

Benedict

R. H.

Motl

R. W.

(2015). Acute effects of walking, cycling, and yoga exercise on cognition in persons with relapsing-remitting multiple sclerosis without impaired cognitive processing speed. Journal of Clinical and Experimental Neuropsychology, 37, 209-219.

22.

Streeter

C. C.

Whitfield

T. H.

Owen

Rein

Karri

S. K.

Yakhkind

. . . Jensen

J. E.

(2010). Effects of yoga versus walking on mood, anxiety, and brain GABA levels: A randomized controlled MRS study. Journal of Alternative and Complementary Medicine, 16, 1145-1152.

23.

Szanton

Rifkind

Mohanty

Miller

Thorpe

Nagababu

. . . Evans

(2011). Racial discrimination is associated with a measure of red blood cell oxidative stress: A potential pathway for racial health disparities. International Journal of Behavioral Medicine, 19, 489-495.

24.

Telles

Bhardwaj

A. K.

Kumar

Balkrishna

(2012). Performance in a substitution task and state anxiety following yoga in army recruits. Psychological Reports, 110, 963-976.

25.

Tuijl

Scholte

de Craen

van der Mast

(2012). Screening for cognitive impairment in older general hospital patients: Comparison of the Six-Item Cognitive Impairment Test with the Mini-Mental State Examination. International Journal of Geriatric Psychiatry, 27, 755-762.

26.

Wilson

Greenfield

Clare

Baddeley

Cockburn

Watson

Nannery

(2008). The Rivermead Behavioural Memory Test (3rd ed.). London, England: Pearson Assessment.

27.

Woods-Giscombé

Lobel

(2008). Race and gender matter: A multidimensional approach to conceptualizing and measuring stress in African American women. Cultural Diversity & Ethnic Minority Psychology, 14, 173-182.

28.

Woods-Giscombé

Gaylord

(2014). The cultural relevance of mindfulness meditation as a health intervention for african americans: implications for reducing stress-related health disparities. Journal of Holistic Nursing, 32, 147–160.