Developing Process-Specific Verbal Memory Interventions for Veterans With TBI

Memory dysfunction can result from impairments along a continuum of information processing, from poor initial acquisition of information during learning to disturbed retrieval of stored memory when it is later needed to perform a task1. The heterogeneous nature of TBI-related memory impairment is well-known, and there is a critical need to better understand such disease heterogeneity in order to enhance diagnosis and therapeutic management2. Several subtypes of memory dysfunction after TBI have been identified3,4. First, some TBI survivors exhibit impaired memory acquisition/encoding (e.g., frontal system damage)5. Second, some exhibit impaired memory consolidation/storage impairment (e.g., prominent damage to temporal lobe systems6). Third, some show impairment in retrieval of information5,7. This heterogeneity results from the variable nature and severity of underlying brain trauma resulting from unpredictable mechanical forces2,8.

It has been suggested that parsing this underlying variability should take precedence over generalities regarding the effect of TBI on memory when conceptualizing or treating memory disorders in this population8 Nevertheless, many rehabilitation programs utilize a "one size fits all" approach to memory training, based (typically) on training compensatory strategies, with no training specifically targeted to the identifiable component processes of memory that could be differentially impaired (encoding, consolidation/storage, and retrieval), and which might respond differentially to more specifically targeted treatment. This situation in clinical practice is due to the lack of evidence upon which to base informed decision-making in allocating specifically targeted memory re-training for individual survivors of TBI, based on clinical test results identifying which memory component processes are impaired (encoding, consolidation/storage, and retrieval). Because of this, there is little attempt to appropriately match patient impairment to targeted treatments.

There are existing training protocols for training these three components of memory processing, as follows: encoding (memory strategy training9), consolidation (errorless learning10), and retrieval (retrieval practice11, but their efficacy has not been tested in TBI survivors with documented impairments in each component. That is, to the investigators' knowledge, there is no solid evidence for memory training in TBI survivors that supports the widely held belief that specifically matching the patient impairment to the treatment leads to better treatment outcomes. This proposal attempts to fill this gap in the investigators' knowledge. Prior to testing the efficacy of these three types of training in a large trial, it is important to make standard preparations, such as refining and testing training materials and ensuring fidelity of treatment methods across clinicians.

Aim 1. Aim 1 is to refine and validate three separate, process-specific memory rehabilitation treatments that focus on improving information-processing at the encoding, consolidation, or retrieval stage for Veterans with chronic moderate/severe TBI.

Objective 1.1. Generate treatment manuals for three process-specific memory treatments.