Objective: Encoding and consolidation deficits appear to account for verbal memory impairment following traumatic brain injury (TBI). It is unknown whether these abilities vary during TBI recovery. We sought to determine the pattern and impact of verbal encoding and consolidation deficits following TBI.
Methods: Twenty-three participants with moderate-to-severe TBI and 25 age- and education-matched control participants' verbal memory abilities were assessed at 2 time points approximately 1 year apart; assessments occurred at acute and chronic visits for TBI survivors.
Main Outcome Measures: Rey Auditory Verbal Learning Test and Item Specific Deficit Approach indices of encoding, consolidation, and retrieval deficits.
Results: In contrast to the controls, participants with TBI showed impaired verbal memory characterized by encoding and consolidation deficits at both time points. The TBI group's short-delayed recall and consolidation scores improved between the acute and chronic assessments. Encoding (primary) and consolidation (secondary) deficits emerged as predictors of acute and chronic recall in the TBI group. Also, acute visit encoding deficits predicted chronic visit delayed recall in TBI survivors, but acute consolidation deficits did not.
Conclusions: These findings suggest that memory rehabilitation efforts focused on improving encoding of verbal material may be useful during both the acute and chronic phases of recovery following TBI.
Department of Psychiatry/Psychology Division, Harbor-UCLA Medical Center, Torrance, California (Dr Wright); and Department of Psychology, Washington State University, Pullman, Washington (Dr Schmitter-Edgecombe).
Corresponding Author: Matthew J. Wright, PhD, Harbor-UCLA Medical Center, 1124 W Carson St, B-4 S, Torrance, CA 90502 (firstname.lastname@example.org).
The authors thank Jonathan Anderson, Randy McDonald, Logan Gantz, and Michael Walton for their assistance in data collection and coding. This research was supported by National Institute of Neurological Disorders and Stroke (NINDS) Grant NS047690.