Comparing semantic autobiographical memory performance in and out of post-traumatic amnesia.

Abstract

OBJECTIVE: Observations of 'shrinking retrograde amnesia' following traumatic brain injury (TBI) date back to the late 1800s, yet there have been no published longitudinal studies using an objective measure to compare semantic autobiographical memory (AM) within the same participants in and out of post-traumatic amnesia (PTA). The purpose of this study was to establish whether a negative gradient (relative preservation of childhood memories over more recent lifetime periods) exists in PTA and its association with demographic and injury-related variables. This has implications for predicting recovery, understanding the relationship between anterograde and retrograde amnesia during PTA, and theories of memory consolidation. PARTICIPANTS AND METHODS: 14 patients with TBI monitored using the Westmead Post-Traumatic Amnesia Scale were administered the Personal Semantic Schedule of the Autobiographical Memory Interview on a single occasion whilst in PTA and within two weeks of emergence. Change in semantic AM with PTA status across Childhood, Early Adult and Recent lifetime periods was examined using paired sample tests, and correlational analyses conducted with time to emergence. RESULTS: Semantic AM was significantly lower in PTA than out of PTA (overall and within each time period, 0 <.001). There was a significant trend whereby those who took fewer days to emerge post-interview scored better overall. CONCLUSIONS. These preliminary results suggest a global impairment in PS memory across lifetime periods in PTA. PS memory performance may be sensitive to the diffuse nature of TBI, and therefore function as a clinically valuable indicator of the likely time to emerge from PTA.