Long-term forgetting in patients with traumatic brain injury

Abstract

Verbal memory impairment has been described in patients with traumatic brain injury (TBI) but the specific altered process, between encoding, consolidation and retrieval, is still discussed. The aim of this study was to use new measures to detect verbal memory impairment in TBI patients. In this purpose, we analyzed encoding and consolidation processes as a function of each patient's performance during a memory test. We calculated a learning score and a percentage of forgetfulness. One-week Free and Cued Selective Reminding Test (1W-FCSRT), which special feature relies on a 30-minutes and a one-week-delayed recall after encoding, was administered to 98 TBI patients (age range at the time of assessment from 20 to 56 years). Their performance was compared to performance of neurologically healthy volunteers matched for age, gender and socio-cultural level. A statistically significant difference was found between TBI patients and healthy volunteers for the learning score (W = 7640.5, P < .001). Indeed, TBI patients (M = 31.45, SD = 35.32) performed worse than the healthy volunteers (M = 51.62, SD = 27.78). Percentage of forgetfulness in TBI patients was above healthy volunteers’ performance and increased with the delay between encoding and retrieval ( P < .001). Our results underlined an altered encoding and a long-term consolidation impairment in TBI patients. It is crucial to detect these deficits to propose a better professional rehabilitation.