A Neuropsychological Study of Patients Exposed to Organic Solvents.

Sixty-seven male patients exposed to organic solvents were neurospychologically examined. Twenty-five subjects had possible causes of encephalopathy other than solvent exposure, leaving 42 patients for the study of the association between exposure and neuropsychological test results. The patients had been heavily exposed for, on average, 24.6 years (range 2-46). The main clinical findings were impairments of psychomotor function, short-term memory, and attention. The results suggest an association between impaired psychomotor speed and exposure duration (r = 0.41; p = 0.007), with moderate to severe impairment occurring after at least 15 years. Forty percent of the patients exposed for more than 30 years had moderate to severely impaired psychomotor speed. The results suggest declining test performance on Trail Making Test B related to exposure duration (r = -0.34; p = 0.03). Further, the individual age-adjusted score on the Digit Span task (WAIS) was reduced when compared with the individual age-adjusted score on the Picture Completion task (WAIS). This reduction was related to exposure duration (r = -0.48; p = 0.002).