Higher white matter hyperintensity load adversely affects pre-post proximal cognitive training performance in healthy older adults

Abstract

Cognitive training has shown promise for improving cognition in older adults. Age-related neuroanatomical changes may affect cognitive training outcomes. White matter hyperintensities are one common brain change in aging reflecting decreased white matter integrity. The current study assessed (1) proximal cognitive training performance following a 3-month randomized control trial and (2) the contribution of baseline whole-brain white matter hyperintensity load, or total lesion volume (TLV), on pre-post proximal training change. Sixty-two healthy older adults were randomized to either adaptive cognitive training or educational training control interventions. Repeated-measures analysis of covariance revealed two-way group × time interactions such that those assigned cognitive training demonstrated greater improvement on proximal composite (total training composite) and sub-composite (processing speed training composite, working memory training composite) measures compared to education training counterparts. Multiple linear regression showed higher baseline TLV associated with lower pre-post change on processing speed training sub-composite (β = -0.19, p = 0.04), but not other composite measures. These findings demonstrate the utility of cognitive training for improving post-intervention proximal performance in older adults. Additionally, pre-post proximal processing speed training change appears to be particularly sensitive to white matter hyperintensity load versus working memory training change. These data suggest that TLV may serve as an important factor for consideration when planning processing speed-based cognitive training interventions for remediation of cognitive decline in older adults.

Keywords: Cognitive aging; Cognitive training; Processing speed; Total lesion volume; White matter hyperintensities.

Fig. 1

ACT study phase 1 procedures and conceptual model. Intensity and duration of study activities were identical between intervention assignments. Phase 2 of study is ongoing; therefore, tDCS condition remains blinded to investigators

Fig. 2

Three-month proximal composite performance by intervention group. Between-group differences on proximal composite as evidenced by Bonferonni-adjusted RM-ANCOVA. Covariates appearing in the model were evaluated at the following values: age = 71.11, sex = 0.45, years of education = 16.19, tDCS group = 0.50. Findings demonstrated that intervention groups did not differ at baseline, both groups improved significantly from baseline to 3-month assessments, and the cognitive training group (black) improved significantly more compared to the education training group (gray)

Fig. 3

Three-month sub-composite training performance by intervention group. Between-group differences in the A processing speed training composite, and B working memory training composite as evidenced by Bonferonni-adjusted RM-ANCOVA. Covariates appearing in the model are evaluated at the following values: age = 71.11, sex = 0.45, years of education = 16.19, tDCS group = 0.50. Findings demonstrate that intervention groups did not differ at baseline, both groups improved significantly from baseline to 3 months on working memory training composite, while only the cognitive training group improved significantly on processing speed training composite. The cognitive training group (black) improved significantly compared to the education training group (gray) across both sub-composites

Fig. 4

Partial regression plot for baseline TLV and 3-month proximal composite. Partial regression plot demonstrating a potentially suggestive trend between baseline log-adjusted TLV and post-intervention proximal composite performance (p = 0.06), while controlling for baseline performance, cognitive training group, tDCS group, age, sex, years of education, scanner type, estimated total intracranial volume, log-adjusted whole-brain TLV, and binarized cardiovascular disease (CVD) risk

Fig. 5

Partial regression plot for baseline TLV and 3-month sub-composite. A partial regression plot demonstrating the relationships between baseline log-adjusted TLV and A processing speed training composite (p = 0.046) and B working memory training composite (p = 0.38), while controlling for baseline performance, cognitive training group, tDCS group, age, sex, years of education, scanner type, estimated total intracranial volume, log-adjusted whole-brain TLV, and binarized cardiovascular disease (CVD) risk. Baseline TLV was a significant predictor for processing speed training composite but not the working memory training composite