[Study of the long term sequelae of traumatic brain injury: evaluation of declarative and procedural memory, and its neuroanatomic substrate].

INTRODUCTION AND OBJECTIVES: The hippocampus and the striatum have been proposed as respectively cerebral substrates of declarative and procedural memory. Both structures are vulnerable to traumatic brain injury. Although declarative and procedural memory have been reported to be impaired in traumatic brain injury (TBI), volumetric measures have so far failed to associate this impairment with atrophy of hippocampal and striatal structures. In our study, we investigated the profile of declarative and procedural memory in children who suffered from moderate to severe traumatic brain injury during childhood (injury test interval: 9.42+/-1.98 years).

PATIENTS AND METHODS: Nineteen patients and matched controls were evaluated on tests of declarative memory and motor learning. Results showed that TBI subjects exhibit poorer performance in both tasks. Moreover, structural magnetic resonance images were obtained from TBI subjects. In order to relate neuropsychological performance with hippocampal and neostriatal volumetric data, correlation analyses were performed.

RESULTS: Significant positive correlations were obtained between hippocampal volume and memory for objects. Striatal volume correlated positively with motor learning and with verbal memory.

CONCLUSIONS: It thus seems that plasticity does not completely compensate for the memory deficits resultant from neural loss in the immature brain.