Psychosocial functioning mediates change in motor and cognitive function throughout neurorehabilitation for adults with acquired brain injury (ABI-RESTaRT).

OBJECTIVES: This study aimed to evaluate the mediational role of change in psychosocial abilities, adjustment and participation on change in motor and cognitive function from admission to discharge from a staged community-based brain injury rehabilitation (SCBIR) service in Western Australia, 2011-2020. METHODS: A retrospective cohort study of n = 324 adults with ABI enrolled in SCBIR using routinely collected rehabilitation outcome measures data. Motor and cognitive function were assessed with the UK Functional Independence and Assessment Measure and psychosocial function with the Mayo-Portland Adaptability Inventory-4. Six multilevel mediation regression analyses were conducted to determine whether change in psychosocial function (abilities, adjustment and participation) mediated change in motor and cognitive function from admission to discharge. RESULTS: Participants demonstrated clinically significant improvements in both motor (+ 11.8, p < 0.001) and cognitive (+ 9.5, p < 0.001) functioning from admission to discharge. Statistically significant improvements in psychosocial abilities (- 4.8, p < 0.001), adjustment (- 2.9, p = 0.001) and participation (- 2.5, p < 0.001) were also seen but were not clinically significant. Mediation analyses showed that participation accounted for 81% of improvements in motor function at discharge and 71% of cognitive function improvements. Adjustment accounted for 26% and 32% of change in motor and cognitive function, respectively. Abilities accounted for 60% of change in cognitive function but did not significantly influence change in motor function. Changes in psychosocial participation fully mediated change in motor function during neurorehabilitation. CONCLUSIONS: Psychosocial function, particularly participation, is an important driver of motor and cognitive recovery throughout neurorehabilitation. Functional rehabilitation programs should target psychosocial improvement as an important mechanism of change.

Interference control in working memory: Evidence for discriminant validity between removal and inhibition tasks.

Working memory (WM) is a system for maintenance of and access to a limited number of goal-relevant representations in the service of higher cognition. Because of its limited capacity, WM requires interference-control processes, allowing us to avoid being distracted by irrelevant information. Recent research has proposed two interference-control processes, which are conceptually similar: (1) an active, item-wise removal process assumed to remove no-longer relevant information from WM, and (2) an inhibitory process assumed to suppress the activation of distractors against competing, goal-relevant representations. The purpose of this study was to determine the extent to which the tasks used to assess removal and inhibition measure the same interference-control construct. Results showed acceptable to good reliabilities for nearly all measures. Similar to previous studies, a structural equation modeling approach identified a reliable latent variable of removal. However, also similar to some previous studies, no latent variable of inhibition could be established. This was the case even when the correlation matrix used to compute the latent variable of inhibition was disattenuated for imperfect reliability. Critically, the individual measures of inhibition were unrelated to the latent variable of removal. These results provide tentative support for the notion that removal is not related to the interference-control processes assessed in inhibition tasks. This suggests that the removal process should be conceptualized as a process independent of the concept of inhibition, as proposed in computational WM models that implement removal as the "unbinding" of a WM item from the context in which it occurred.