Information on the prognosis and electrophysiological follow-up of severe thallium poisoning is limited. We report two patients (mother and daughter) who were repeatedly exposed to thallium poisoning experienced hair loss, polyneuropathy, and visual impairment. Nerve conduction studies (NCSs), visual evoked potentials (VEP), brainstem auditory evoked potentials (BAEP) changes, and optical neuropathy developed within a few months latency after the first subjective signs. Normal findings of these electrophysiological methods in the first 2 weeks therefore led in one of our patients to exclusion of thallium as the cause of symptoms. Thallium poisoning was, however, later confirmed by toxicological analysis of blood and/or urine and feces in both the patients and in the microscopic hair analysis of the daughter. Both patients were treated with Prussian blue that increased the elimination of thallium in urine and feces. The hair loss was fully reversible. During a 2-year follow-up after the poisoning, polyneuropathy in the lower extremities improved substantially, but residual impairment in both motor and sensory function, NCSs, VEP, and BAEP remained. Additionally, severe asymmetrical vision impairment persists in both women, with central scotomata and impaired color discrimination in both eyes. Substantial improvement of their visual function is unlikely.

Anticoagulant (Dicumarol) therapy was given for five to six weeks to 15 hospital patients with organic brain damage secondary to alcoholism. The results were excellent in 5, good in 7 and poor in 3 cases; 8 of the patients could be discharged home.

A “single‐blind” study on the use of anticoagulant therapy in 8 geriatric patients with chronic brain syndrome indicated that the subjects performed significantly less well on the Graham‐Kendall test (for organic abnormalities) both immediately after, and three months after cessation of a 4‐month course of treatment. Scores from the Mental Status Questionnaire indicated a significant improvement in psychological functioning after treatment. However, the apparent contradiction in these results could be attributed to differences in the maintenance of positive effects engendered by the initial high levels of motivation. Our findings plus those of Walsh and Rosenberg suggest that a carefully controlled study involving more patients and more varied measuring techniques would add useful information to the understanding of chronic brain syndrome.

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