Lateralization of deficit in self-awareness of memory in patients with intractable epilepsy

Purpose: Memory disorders are prominent among patients with intractable epilepsy. It has, however, been frequently observed that subjective memory complaints of these patients did not match their performance on objective memory tests. This discrepancy may reflect emotional, cognitive, or self-awareness deficits among these individuals. The aim of the current study was to explore the interference of cerebral dysfunction on accuracy of self-appraisal for memory. Methods: The degree of concordance between self-perception of memory function, as measured by a visual analogue scale, and actual performance on memory tests was computed in 35 patients who were candidates for epilepsy surgery and demographically matched normal control subjects. The difference between the self-estimated memory ability and performance on memory tests and its relation to the laterality of an epileptogenic lesion, cognitive factors, and affective status was then examined. Results: The results show that the discrepancy between the self-estimated memory ability and performance on memory tests in patients with right hemisphere epileptogenic lesions was significantly larger in magnitude compared with that in patients with left hemisphere lesions and demographically matched control subjects (p = 0.001). Furthermore, whereas patients with left hemisphere lesions and normal controls had about an equal number of positive and negative discrepancy scores, all patients with right hemisphere lesions had positive discrepancy scores, suggesting a tendency for overestimation of memory abilities. Conclusions: These results suggest that right hemisphere lesions may introduce a systematic bias in self-awareness for memory. This bias may color patients' perceptions of self and others, affecting their perceptions of the quality of life, and necessitating an adjustment of the treatment goals and procedures.