[Chronic toxic encephalopathies caused by metallic mercury].

On the basis of neurological, psychological and electroencephalographic investigations the authors present an assessment of the state of the nervous system in 24 males observed in hospital for suspected chronic intoxication with metallic mercury. The most frequent symptoms were: headaches and dizziness (17 cases), recent memory disturbances (16) and irritability (15). Cerebellar signs were found in 13 cases, one eeg record was abnormal, in 4 cases the eeg was borderline normal. Psychological tests revealed in 21 cases evidence of organic brain damage with slowing down of the simple visual and auditory reactions (16), disturbances of recent memory and persistent attention (14), decreased intellectual efficiency (7) and visual perception (5). The authors call attention to the necessity of appropriate prevention of mercury poisoning in view of its selective neurotoxicity and irreversibility of the pathological changes. The importance of psychological testing for psychological testing for the correct assessment of the status of the nervous system in cases of metallic mercury poisoning is stressed.