Using Cognitive Intraindividual Variability to Measure Intervention Effectiveness: Results from the Baltimore Experience Corps Trial

Improved intraindividual variability in cognitive performance following cognitive and exercise training in older adults

OBJECTIVE

Increased intraindividual variability (IIV) of cognitive performance is a marker of cognitive decline in older adults. Whether computerized cognitive training (CCT) and aerobic exercise counteracts cognitive decline by reducing IIV is unknown. We investigated the effects of CCT with or without aerobic exercise on IIV in older adults.

METHODS

This was a secondary analysis of an 8-week randomized controlled trial. Older adults (aged 65-85 years) were randomized to CCT alone (n = 41), CCT with aerobic exercise (n = 41), or an active control group (n = 42). The CCT group trained using the Fit Brains® platform 3×/week for 1 hr (plus 3×/week of home-based training). The CCT with aerobic exercise group received 15 min of walking plus 45 min of Fit Brains® 3×/week (plus 3×/week of home-based training). The control group received sham exercise and cognitive training (3×/week for 1 hr). We computed reaction time IIV from the Dimensional Change Card Sort Test, Flanker Inhibitory Control and Attention Test (Flanker), and Pattern Comparison Processing Speed Test (PACPS).

RESULTS

Compared with the control group, IIV reduced in a processing speed task (PACPS) following CCT alone (mean difference [95% confidence interval]: -0.144 [-0.255 to -0.034], p < 0.01) and CCT with aerobic exercise (-0.113 [-0.225 to -0.001], p < 0.05). Attention (Flanker congruent) IIV was reduced only after CCT with aerobic exercise (-0.130 [-0.242 to -0.017], p < 0.05).

CONCLUSIONS

A CCT program promoted cognitive health via reductions in IIV of cognitive performance and combining it with aerobic exercise may result in broader benefits.

Cognitive intra-individual variability in breast cancer survivors: A systematic review

Subjective and objective cognitive impairments in Breast Cancer Survivors (BCS) often do not correlate. One important contribution to the reported disparities may be the reliance on mean-based cognitive performance. Cognitive intra-individual variability (IIV) may provide important insights into these reported disparities. Cognitive IIV refers to the fluctuation in performance for an individual on either one cognitive task across a trial or dispersed across tasks within a neuropsychological test battery. The purpose of this systematic review was to search for and examine the literature on cognitive IIV in BCS. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) approach was used to search for all articles related to cognitive IIV in BCS. MEDLINE (via PubMed), Embase, and Scopus databases were searched using detailed search terms and strategies. Initially, 164 articles were retrieved but only 4 articles met the criteria for this systematic review. BCS differed from healthy controls in similar ways across the four studies, generally demonstrating similar performance but showing increased cognitive IIV for the more difficult tasks. Differences were enhanced later during chemotherapy. The four studies provide support for cognitive IIV as a useful measure to detect the subtle objective cognitive change often reported by BCS but frequently not detected by standard normed-based cognitive testing. Unexpectedly, measures of cognitive IIV were not consistently associated with self-reported measures of cognition.

Cognitive and Functional Improvement via Novel Skill Learning for Low-Income Minoritized Middle-Aged and Older Adults

Prior research has demonstrated beneficial outcomes for learning new skills in older adulthood, including increased cognitive and functional abilities, which help prevent age-related declines and foster healthy aging. However, these studies largely have included participants not typically considered at risk for cognitive and functional decline (i.e., White, highly educated, higher income). Cognitive and functional disparities exist among minoritized racial and ethnic individuals, particularly Black and Latinx populations, because of a lifetime of inequalities associated with low socioeconomic status, low education, and discrimination. This theoretical paper proposes a potential pathway in which such disparities could be mitigated by increasing cognitive and functional abilities via novel skill learning in these at-risk populations in middle and later life to prevent decline. We also discuss indirect barriers (e.g., financial and health issues), direct barriers (e.g., limited learning opportunities), and motivational barriers (e.g., self-beliefs, values) that these adults may encounter. We further highlight that addressing these barriers to novel skill learning by providing appropriate resources is necessary to maximize the feasibility and potential effectiveness of this pathway. Lastly, we encourage future research to test this pathway and help inform policymakers and existing learning programs to implement better ways of promoting lifelong learning in an inclusive and equitable manner to prevent decline.

Pandemic Pivots for Older Volunteers: Online Tutoring and Pen Pal Programs

This study explored the experiences of older adult volunteers who pivoted from in-person tutoring to letter writing and online tutoring during the COVID-19 pandemic. Sixty-one older adult volunteers were surveyed in the beginning and end of the school year about their experiences, including their perceived benefits, challenges, and feedback on the pandemic transition. Eleven of the surveyed volunteers participated in focus groups at the end of the school year. Perceived benefits included having a positive impact on a child's life and meaningful engagement during the pandemic, and perceived challenges included difficulty engaging students and lack of control over learning environments. The participants also suggested increasing opportunities for informal interactions with staff and students, technology training, and peer support between volunteers. There was agreement that the remote volunteering experience was not a substitute for in-person tutoring, but it was better than no volunteering at all.

A Comparison of the Effect of Physical Activity and Cognitive Training on Dual-Task Performance in Older Adults

OBJECTIVES

Studies suggest that cognitive training and physical activity can improve age-related deficits in dual-task performances. However, both of these interventions have never been compared in the same study. This article investigates the improvement in dual-task performance in 2 types of exercise training groups and a cognitive training group and explores if there are specific dual-task components that are more sensitive or more likely to improve following each type of training.

METHODS

Seventy-eight healthy inactive participants older than the age of 60 (M = 69.98, SD = 5.56) were randomized to one of three 12-week training programs: aerobic training (AET) = 26, gross motor abilities (GMA) = 27, and cognition (COG) = 25. Before and after the training program, the participants underwent physical fitness tests, and cognitive evaluations involving a computerized cognitive dual task. The AET consisted of high- and low-intensity aerobic training, the GMA of full-body exercises focusing on agility, balance, coordination, and stretching, and the COG of tablet-based exercises focusing on executive functions.

RESULTS

Repeated-measures analysis of variance on reaction time data revealed a group × time interaction (F(2,75) = 11.91, p < .01) with COG having the greatest improvement, followed by a significant improvement in the GMA group. Secondary analysis revealed the COG to also improve the intraindividual variability in reaction time (F(1,24) = 8.62, p < .01), while the GMA improved the dual-task cost (F(1,26) = 12.74, p < .01).

DISCUSSION

The results show that physical and cognitive training can help enhance dual-task performance by improving different aspects of the task, suggesting that different mechanisms are in play.

Using intraindividual variability as an indicator of cognitive improvement in a physical exercise intervention of older women with mild cognitive impairment

OBJECTIVES

Intervention programs designed to improve cognitive ability in older adults with mild cognitive impairment (MCI) have often focused on physical exercise as a means to improve traditional measures of cognition, with mixed success. Individuals with MCI show high levels of intraindividual variability (IIV) in response speed, and IIV may be sensitive to intervention-related changes. The current study evaluated if participants who participated in a physical activity intervention (aerobic or resistance training) showed a reduction in IIV, compared to a balance and tone control group.

METHOD

This study was a secondary analysis of the EXercise for Cognition and Everyday Living (EXCEL) Study. Women Aged 70-80 years with probable MCI (n = 86) participated in a 6-month randomized controlled trial designed to investigate the effects of different physical exercises on cognitive ability. Participants completed 1-back, task switching, and spatial working memory tasks at baseline, 13 weeks (midpoint) and upon completion of the program.

RESULTS

Analyses were conducted following both the intent-to-treat principle and complier average casual effect (CACE) modeling. Participants in the intervention group who complied with the program showed reduced IIV on task switching in the CACE models. The intent-to-treat analyses were all nonsignificant.

CONCLUSIONS

Physical exercise resulted in improved IIV in older adults with probable MCI, showing that IIV is modifiable by lifestyle engagement. IIV may be a useful complementary index of cognitive plasticity particularly among those with cognitive impairment. (PsycInfo Database Record (c) 2020 APA, all rights reserved).