Aim: Longitudinal study of verbal learning and memory processes after traumatic brain injury (TBI).
Patients and methods: Twenty-six patients who had sustained a moderate-severe TBI were assessed with a Spanish version of the California Verbal Learning Test at the time of admission and 6-months after inclusion in a multidisciplinary rehabilitation program that comprised rehabilitation strategies for memory impairments. Global memory indexes were determined, including retroactive interference, proactive interference and recall indexes controlled for level of verbal acquisition. Memory change over time was correlated to demographic and clinical relevant variables, including the level of patients' self-awareness.
Results: More than 75% of our patients presented learning, immediate memory and delayed memory deficits at baseline, with an important effect of retroactive interference (69%). At 6-month follow-up, 34.6% showed learning difficulties, 46.2% immediate memory deficits, and 53% delayed memory problems, with 34.6% of the patients showing retroactive interference. Chronicity, level of self-awareness and premorbid intelligence correlated to the degree of memory change over time.
Conclusions: Prominent verbal memory problems developed, not only during the first months after TBI but also over time are mostly due to impaired consolidation related to an intense retroactive interference. These data should be considered when developing memory rehabilitation strategies.