Abstracts

RATIONALE: Previous research has described cognitive impairment associated with metabolic changes in the hippocampus detected with ¹H MRSI. These deficits are also presumed to correspond to structural change in the mesial temporal lobes visible on MRI. This study examined the possibility that ¹H MRSI may be associated with neuropsychological deficits in the absence of positive findings on MRI.
METHODS: The neuropsychological profiles of 5 temporal lobe epilepsy patients (2L; 3R) with negative MRI but positive ¹H MRSI were reviewed. A total of 12 memory scores derived from the Wechsler Memory Scale III, Buschke Verbal Selective Reminding Test, Nonverbal Selective Reminding Test and the Rey Osterreith Complex Figure were compiled for each patient. Scores falling more than 1 SD below the mean for each measure were considered impaired. Scores on measures of general intellectual ability, naming, verbal fluency, judgment and planning, and spatial judgment were also examined using similar performance criteria.
RESULTS: Full scale IQ was within the average range for all five patients. However, all five were impaired on two or more of the 12 memory measures (mean number of memory scores in impaired range = 5.4 per patient). Two patients also demonstrated impaired confrontation naming. No other deficits were identified.
CONCLUSIONS: Metabolic abnormalities in the hippocampus identified on ¹H MRSI are associated with impaired memory performance even in the absence of structural change on MRI. The increased sensitivity of ¹H MRSI should improve the diagnosis and treatment of patients with temporal lobe epilepsy.