Injury and recovery: severe amnestic syndrome following traumatic brain injury

To illustrate the clinical course of a patient with a marked amnestic syndrome resulting from a closed head injury that had significant effects on frontal and thalamic memory structures.

The patient underwent a series of brain imaging investigations (CT and MRI) and neuropsychological investigations to determine the severity and course of behavioural and cognitive impairments.

Three months post-injury, the patient demonstrated dense retrograde and anterograde amnesia for auditory-verbal and visuo-spatial information, disorientation and confabulation. In contrast, memory for faces appeared unimpaired. One month later the patient's behaviour, orientation and spatial memory had improved with no concomitant improvement in auditory-verbal memory.

The findings indicate that injury to the diencephalon manifests in a verbal amnesic syndrome that is anterograde in nature if localized in the region of the anterior left thalamus, but leaves a relatively intact visual memory. Furthermore, injuries to the frontal and temporal lobes and their projections to the diencephalon may be more important in the emergence and resolution of retrograde amnesia and disturbances in autobiographical recall than previously appreciated.