Prospective clinical and psychometric investigation of patients with chronic toxic encephalopathy induced by solvents.

Sixty-two patients with chronic toxic encephalopathy diagnosed in 1976-1981 were considered for reexamination in 1983-1984. Thirteen were found to have other diseases that might contribute to brain dysfunction. Seventeen were unwilling or unable to participate. The final group consisted of 32 men 33 to 63 (median 55) years of age who were physically and psychometrically reexamined with the same methods used in the initial investigation. The interval between the first and present examination was 21-88 (median 48) months, and exposure to solvents had ceased. The subjects reported some improvement in their neurasthenic problems. In particular they suffered less from fatigue, headache, and dizziness. When diagnosed they had an average of seven out of ten typical neurasthenic symptoms included in the toxic encephalopathy syndrome. At the time of the follow-up the mean number of symptoms had decreased significantly to five. The psychometric retesting showed significant deterioration in verbal memory, improvement in visual memory, and unchanged results on the other tests. In conclusion, these toxic encephalopathy patients improved subjectively when exposure stopped. Psychometrically they performed very close to the initial testing, which excluded progressive brain disease or subacute pharmacological solvent intoxication.