CEREBRAL EVOKED RESPONSES IN HYPOTHYROIDISM

Cerebral evoked responses to light have been studied in forty-five patients with hypothyroidism and forty-five normal subjects matched for age and sex. Average latencies of all waves examined were longer for the patient sample, some of the differences being highly significant on statistical testing. With one exception, average amplitudes of the waves were smaller in patients with hypothyroidism as compared with normal subjects. The lone exception was the second occipital wave, surface positive, which had a significantly larger amplitude. Replacement therapy resulted in normalization of cerebral responses, no significant differences being found between treated patients and controls. Evoked responses obtained from patients at rest and during a reaction time task were different in several respects. The findings were discussed in relation to the effect of level of attention upon electrocortical activity. © 1968.