Individual Differences in Working Memory Capacity Predicts Responsiveness to Memory Rehabilitation After Traumatic Brain Injury

Objective: To explore how individual differences affect rehabilitation outcomes by specifically investigating whether working memory capacity (WMC) can be used as a cognitive marker to identify who will and will not improve from memory rehabilitation. Design: Post hoc analysis of a randomized controlled clinical trial designed to treat learning and memory impairment after traumatic brain injury (TBI): 2 x 2 between-subjects quasiexperimental design (2 [group: treatment vs control] x 2 [WMC: high vs low]). Setting: Nonprofit medical rehabilitation research center. Participants: Participants (N=65) with moderate to severe TBI with pre- and posttreatment data. Interventions: The treatment group completed 10 cognitive rehabilitation sessions in which subjects were taught a memory strategy focusing on learning to use context and imagery to remember information. The placebo control group engaged in active therapy sessions that did not involve learning the memory strategy. Main Outcome Measure: Long-term memory percent retention change scores for an unorganized list of words from the California Verbal Learning Test-H. Results: Group and WMC interacted (P=.008, eta(2)(p)=.12). High WMC participants showed a benefit from treatment compared with low WMC participants. Individual differences in WMC accounted for 45% of the variance in whether participants with TBI in the treatment group benefited from applying the compensatory treatment strategy to learn unorganized information. Conclusions: Individuals with higher WMC showed a significantly greater rehabilitation benefit when applying the compensatory strategy to learn unorganized information. WMC is a useful cognitive marker for identifying participants with TBI who respond to memory rehabilitation with the modified Story Memory Technique. (C) 2016 by the American Congress of Rehabilitation Medicine