ABSTRACT
Thyroid disorders had been incriminated a lot in reversible dementia at the end of the last century. Yet, the relation between myxedema per se and cognitive dysfunction has been of great concern nowadays. is to screen the incidence and delineate the characteristics of cognitive dysfunction that may occur in association to hypothyroidism; also to decide the best test to achieve rapid diagnosis in such a problem our study included 50 subjects; 30 patients [20 patients with overt hypothyroidism and 10 with subclinical hypothyroidism] and 20 healthy subjects serving as control group. All were submitted to general medical and neurological examination, laboratory investigations to complete the diagnosis of hypothyroidism, MRI brain, P300 latency assessment and neuropsychological assessment [WAIS-R,WMS-R and tests for frontal executive functions]. A definite cognitive impairment in both hypothyroid patient's group was noted in comparison to controls, as proved by statistically significant prolonged absolute P300 latency and positive neuropsychological tests among them. WAIS subtests especially: [Picture arrangement test, Block design test and Digit backward test] can be used as a premonitory test to detect cognitive dysfunction with hypothyroidism