Impairment of short-term memory in left hemispheric traumatic brain injuries

We report on two patients with traumatic lesions in the temporal and parietal lobes who demonstrated disturbances of short-term memory (STM) following improvement on the aphasia. Patient 1 was a 66-year-old right-handed man who presented to our hospital with a cerebral contusion. One admission we observed a Wernicke's aphasia with paraphasic jargon in this patient that resolved within 8 weeks. Patient 2 was a 35-year-old right-handed woman, with an acute subdural haematoma and a cerebral contusion, who underwent craniotomy and evacuation of the haematoma. In this patient we noted a transient Wernicke's aphasia following the operation that improved within 3 months. Linguistically, the aphasia observed in each of these two patients was not a typical conduction aphasia because of the absence of paraphasia, and impairment of comprehension was unclear despite a decrease in performance on repetition tasks. Both verbal and non-verbal tasks suggested an impairment in STM. These findings suggest that involvement of the left hemisphere may cause disturbances in both verbal and non-verbal STM.