Sustaining prospective memory functioning in amnestic mild cognitive impairment: A lifespan approach to the critical role of encoding.

Abstract

Objective: Prospective memory (PM), the ability to remember to perform future activities, is a fundamental requirement for independent living. PM tasks pervade throughout our daily lives and PM failures represent one of the most prominent memory concerns across the entire lifespan. This study aimed to address this issue by exploring the potential benefits of specific encoding strategies on memory for intentions across healthy adulthood and in the early stages of cognitive impairment. Method: PM performance was explored through an experimental paradigm in 96 participants: 32 amnestic mild cognitively impaired patients aged 64-87 years (M=6.75, SD=5.88), 32 healthy older adults aged 62-84 years (M=76.06, SD=6.03) and 32 younger adults 18-22 years (M=19.75, SD=1.16). The potential benefit of the use of enactment (i.e. physically simulating the intended action) at encoding to support an autonomous performance despite neuronal degeneration was assessed. Results: PM was consistently identified as a sensitive and specific indicator of cognitive impairment. Importantly, enacted encoding was consistently beneficial for PM performance of all the participants, but especially so in the case of healthy and cognitively impaired older adults. These positive results have unveiled the potential of this encoding technique to optimize attentional demands through an adaptive allocation of strategic resources across, both, a healthy and cognitively impaired sample. Theoretical implications of this work are discussed as well as the considerable translational potential to improve social well-being. Conclusions: A better understanding of the strategies that can enhance PM offers the potential for cost effective and widely applicable tools which may support independent living across the adult lifespan.

Prospective Memory Training in Older Adults: A Systematic Review and Meta-Analysis

“…Previous studies have reported age-related PM decline in healthy older adults (Ball et al, 2019 ; Gonneaud et al, 2017 ; Lamichhane et al, 2018 ), which supports the association between ageing and PM decline. In the included studies, the clinical populations demonstrated a significantly poorer PM performance than the healthy populations (Kinsella et al, 2016 ; Lee et al, 2016 ; Mateos et al, 2016 ; Ozgis et al, 2009 ; Pereira et al, 2015 , 2018 ; Shelton et al, 2016 ), which supports a deficit in PM. The positive training effect found for the healthy and clinical older populations may reflect an improvement in PM in the training group compared with the control group.…”

“…After excluding these studies, we had 2,672 participants across 42 studies with enough details to calculate the average demographic statistics (weighted M age = 72.01 years, SD = 6.45, range = 50–94). 3 An additional 12 studies did not report sufficient data for calculating the number of participants in the training and control conditions separately 4 (Altgassen et al, 2015 ; Kinsella et al, 2016 ; Lee et al, 2013 ; McDougall, 2000 ; McFarland & Glisky, 2011 ; Niedźwieńska et al, 2014 ; Pereira et al, 2012 , 2015 , 2018 ; Schnitzspahn & Kliegel, 2009 ; Villa & Abeles, 2000 ; Zimmermann & Meier, 2010 ). As a result, the remaining 30 included studies 5 had 993 participants (weighted M age = 72.13 years, SD = 6.44, range = 50–93) in the training condition and 698 participants (weighted M age = 71.48 years, SD = 6.42, range = 50–94) in the control condition.…”

“…The training gains of the two populations showed mixed trends. Some studies proposed that the healthy population stood to gain more than the clinical populations (Kinsella et al, 2016 ; Pereira et al, 2018 ), whereas others proposed that the clinical population would have a larger training gain (Lee et al, 2016 ; Mateos et al, 2016 ; Ozgis et al, 2009 ). One study showed no interaction effects between the cognitive status and training conditions (Pereira et al, 2015 ).…”

Effect of Encoding on Prospective Memory

“…The sample size was based on an a priori power analysis using the GPOWER 3 software. The effect size f was based on previous research ( Pereira et al, 2018 ). The alpha level was 0.05, power was 0.95, and an effect size of 0.5 was considered.…”

“…For encoding, these previous studies (e.g., Ball and Bugg, 2018 ) showed a “specific advantage”, indicating that the memory content comprised mostly specific events with a high proportion of specific memories; to recall this content, there was an advantage to remembering specific details ( Chen, 2013 ). Furthermore, Scullin et al (2018) systematically investigated the encoding process for ProM and confirmed that specific was better than non-specific cue encoding, for which 22.5% of participants gave little thought to the ProM tasks and tended to translate categories to specific exemplars ( Pereira et al, 2018 ). It may be that participants using non-specific cue encoding had to pay closer attention than those using specific cue encoding to correctly determine ProM targets.…”