Effects of equine-assisted interventions on older adults' health: A systematic review.

Objective: Equine-assisted interventions (EAI) can improve a variety of health problems in older adults and thus promote their well-being. This systematic review aimed to synthesize studies on EAI to understand better their effects on the health of older adults. Method: A systematic search guided by the PRISMA 2020 approach was performed on specific databases: Medline (PubMed), EMBASE, PsycINFO, and Cochrane Library. Peer-reviewed articles published in the English language from inception to June 2022 were retrieved. Methodological quality was established using the modified version of the Downs and Black checklist. Results: A total of 244 studies were retrieved, and 13 eligible studies were finally included. Three health domains were investigated: physical (balance, gait, and muscular strength), psychological (quality of life and cognitive assessment), and physiological (hormonal measures, cerebral and muscular activity). Among the eight studies investigating the physical dimension, four studies highlighted a positive effect of EAI on balance, four for gait, and three for strength. Regarding the three studies investigating the psychological dimension, two studies showed a positive effect of EAI on quality of life. Lastly, the four studies investigating the physiological dimensions all demonstrated a positive effect of EAI on hormonal measures and cerebral and muscular activity. Conclusion: Nevertheless, this systematic review provides promising findings regarding the positive effects of EAI on physical, psychological, and physiological health in older adults. Research on EAI should therefore be pursued rigorously to promote this non-pharmacological intervention in an older adult population.

The age-related effect on electrophysiological correlates of successful episodic memory encoding supports the hypothesis of a deficit in self-initiated encoding processes in aging.

Episodic memory decline with aging may be due to an age-related deficit in encoding processing, older adults having increasing difficulty to self-initiate encoding strategies that support later retrieval. Using event-related potentials (ERPs), the present study explored for the first time the neural correlates of successful encoding in a resource-dependent episodic memory task, in which participants had to self-initiate processes at both encoding and retrieval. At the behavioral level, results confirm the better memory performance of young than older adults. Comparing the neural activity elicited by studied items that were and were not subsequently recalled (Subsequent Memory Effect, SME), electrophysiological data revealed that younger adults showed a significant and sustained SME, shifting from parietal to frontal areas, suggesting that they self-initiated deep encoding strategies. In older adults, the duration of brain activity was shorter and located more in the parietal than frontal areas, suggesting that they used shallow rather than deep processes. Consistent with the hypothesis of a deficit in self-initiated strategies in aging, our findings suggest that when older adults are faced with a difficult memory task (no encoding support and no cue at retrieval), they engage fewer elaborative strategies than young adults, resulting in impaired episodic memory performance.

Neural correlates of episodic memory change in increasing age: a longitudinal event-related potential study.

Using a longitudinal design, we examined whether event-related brain potentials (ERPs) correlates of successful episodic memory retrieval varied over a 4-year period according to the level of memory change. ERPs were recorded while participants performed a word-stem cued-recall task, and this procedure was repeated 4 years later. We compared the ERP old/new effect patterns of participants whose memory performance remained stable over time (stable group) with those of participants experiencing episodic memory decline (decline group). The pattern of change of the old/new effect differed between groups. At T1, the two groups exhibited the same pattern, with a positive frontal and parietal old/new effect. For the decline group, the old/new effect pattern did not change between T1 and T2. By contrast, for the stable group, the positive parietal old/new effect at T1 no longer appeared at T2, but a negative old/new effect was exhibited at frontal sites. This brain reorganization pattern could be a compensatory mechanism supporting strategic processes and allowing memory abilities to be maintained over time.

Event-related brain potential correlates of brain reorganization of episodic memory throughout the adult lifespan.

The main aim of this study was to characterize the age-related evolution of the event-related brain potentials correlates of successful to tackle the neural reorganization patterns associated with this episodic retrieval. We thus examined the evolution of the event-related brain potential old/new effect across the adult lifespan, in five groups, aged 21-70 years (21-30, 31-40, 41-50, 51-60, and 61-70 years), equalized on their memory performance through a word-stem cued-recall task. This procedure makes it possible to examine the evolution of age-related changes in brain organization during adulthood and to specify the age onset of these changes. Results confirm the hypothesis that aging is associated with major changes in brain functioning. These changes appear to be consistent with both the HAROLD and PASA hypotheses, which postulate an age-related reduction in hemispheric asymmetry and a shift from posterior to anterior areas, respectively. What is notable is that these patterns of brain reorganization are not specific to older stages of life as they begin to develop very early in adult life, around the 30s, and the shift toward frontal regions strengthens in the 60s.