Electroencephalographic photosensitivity among Zimbabwean youths

To clarify the factors associated with electroencephalographic (EEG) photos ensitivity, the records of patients who had EEG examinations in the city of Harare, Zimbabwe between 1968 and 1996 were studied. EEG photosensitivity was confirmed in 107 of a total of 9082 youths (aged 0-25 years), giving an overall photosensitivity prevalence of 1.17% in the study population. Phot osensitivity occurred more frequently in females than in males, and the pea k age period for its occurrence was during adolescence. A significantly hig her prevalence of photosensitivity was recorded among Whites and Asians tha n among Blacks, while the Coloured population had an intermediate prevalenc e. The monthly and seasonal incidence of photosensitivity in the present st udy showed no correlation with the prevailing mean monthly or seasonal temp eratures, sunshine duration and sunlight intensity in Harare during the per iod covered by the study. These findings indicate that sunshine-related fac tors do not play a dominant role in the occurrence of photosensitivity, the reby negating previous opinions which attributed the relative rarity of pho tosensitivity in black Africans to high levels of exposure To sunshine in t ropical Africa. Our findings therefore corroborate the view that photosensi tivity depends primarily on genetic rather than environmental factors.