Interhemispheric differences in photosensitive epilepsy. II. Intermittent photic stimulation.

Of a consecutive series of 138 photosensitive epileptic patients 57 showed a unilateral preponderance of asymmetrical discharges on IPS, significant in each individual at the 5% level. There was no association between asymmetry of IPS-induced discharges and clinical evidence of cerebral pathology (partial or secondary generalized epilepsy, neurological deficit, left handedness, etc.). It is concluded that these results, together with our previous findings of asymmetrical pattern sensitivity suggest that the cortical hyperexcitability postulated in primary cortico-reticular epilepsy is not uniformly distributed.