Dementia as a neuropsychological consequence of chronic occupational exposure to polychlorinated biphenyls (PCBs)

Previous epidemiological and clinical studies of humans exposed to polychlorinated biphenyls (PCBs) indicate that the majority of patients have neurological complaints (e.g., headache, vertigo, paresthesias, poor memory and concentration, fatigue, depression). Since only a small minority of PCB-exposed patients demonstrate abnormalities on objective neurological measures (e.g., CT-scans, EEC, nerve conduction velocity), it is particularly unfortunate that objective neuropsychological data has not been published to substantiate patient complaints. The present study provides neuropsychological test data on two patients exposed to PCBs. In both cases, PCB exposure is documented by an analysis of PCB levels in the patients' work environments. Despite the absence of abnormalities on CT-scans and EEC, both patients displayed a variety of cognitive deficits and emotional disturbance. Serial assessment of one patient with high blood levels of PCBs revealed a dementia (sharing certain features with Alzheimer's disease) and an organic affective syndrome. Assessment of a second patient exposed to PCBs (but with no detectable blood levels of PCBs) suggested that his cognitive impairments were not due to PCB exposure. The present study provides data which points to the importance and sensitivity of neuropsychological examination in cases of PCB-exposure.