Strategy-based reasoning training modulates cortical thickness and resting-state functional connectivity in adults with chronic traumatic brain injury.

Kihwan Han,Sandra B Chapman,Rebecca A Davis,Daniel C Krawczyk

doi:10.1002/brb3.687

Abstract

IntroductionPrior studies have demonstrated training‐induced changes in the healthy adult brain. Yet, it remains unclear how the injured brain responds to cognitive training months‐to‐years after injury.MethodsSixty individuals with chronic traumatic brain injury (TBI) were randomized into either strategy‐based (N = 31) or knowledge‐based (N = 29) training for 8 weeks. We measured cortical thickness and resting‐state functional connectivity (rsFC) before training, immediately posttraining, and 3 months posttraining.ResultsRelative to the knowledge‐based training group, the cortical thickness of the strategy‐based training group showed diverse temporal patterns of changes over multiple brain regions (p vertex < .05, p cluster < .05): (1) increases followed by decreases, (2) monotonic increases, and (3) monotonic decreases. However, network‐based statistics (NBS) analysis of rsFC among these regions revealed that the strategy‐based training group induced only monotonic increases in connectivity, relative to the knowledge‐based training group (|Z| > 1.96, pNBS < 0.05). Complementing the rsFC results, the strategy‐based training group yielded monotonic improvement in scores for the trail‐making test (p < .05). Analyses of brain–behavior relationships revealed that improvement in trail‐making scores were associated with training‐induced changes in cortical thickness (p vertex < .05, p cluster < .05) and rsFC (p vertex < .05, p cluster < .005) within the strategy‐based training group.ConclusionsThese findings suggest that training‐induced brain plasticity continues through chronic phases of TBI and that brain connectivity and cortical thickness may serve as markers of plasticity.

Highlights

Prior studies have demonstrated training-induced changes in the healthy adult brain
Statistically significant group differences in nonmonotonic cortical thickness changes over time were observed in the bilateral dorsolateral prefrontal cortex (DLPFC) and anterior medial prefrontal cortex (AMPFC); left subcentral gyrus (L SCG); and right dorsal prefrontal cortex (R DPFC)
Within-group contrast maps, corrected for multiple comparisons (Figure 2a), revealed that the statistically significant group differences were attributable to (1) increases followed by decreases in cortical thickness of the Strategic Memory Advanced Reasoning Training (SMART) group in the L DLPFC and R AMPFC, and (2) decreases followed by increases in cortical thickness of the Brain Health Workshop (BHW) group in the L SCG and L AMPFC. (Figures 2a and S3a)

Summary

Introduction

Prior studies have demonstrated training-induced changes in the healthy adult brain It remains unclear how the injured brain responds to cognitive training months-to-years after injury. Methods: Sixty individuals with chronic traumatic brain injury (TBI) were randomized into either strategy-based (N = 31) or knowledge-based (N = 29) training for 8 weeks. Analyses of brain–behavior relationships revealed that improvement in trail-making scores were associated with training-induced changes in cortical thickness (pvertex < .05, pcluster < .05) and rsFC (pvertex < .05, pcluster < .005) within the strategy-based training group. TBI rehabilitation research is increasing, which has revealed some major challenges related to studying TBI populations These challenges include: (1) the heterogeneity of TBI and (2) limitations of conventional behavioral measures and neuroimaging techniques to identify the TBI-related abnormalities and changes after rehabilitation in this population. Neuropsychological tests have been criticized for the lack of ecological validity, meaning the test scores do not adequately reflect daily function levels (Burgess et al, 2006)

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Discussion

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