Neurologic syndrome in 25 workers from an aluminum smelting plant
D. M. White, W. T. Longstreth Jr, L. Rosenstock, K. H. Claypoole, C. A. Brodkin and B. D. Townes
Department of Rehabilitation Medicine, University of Washington Medical Center, Seattle 98195.
BACKGROUND--This article expands on an earlier series of three patients
with a neurologic syndrome, who had all worked in an aluminum smelting
plant. METHODS--Twenty-five symptomatic workers from the same plant were
referred for a standardized evaluation, including completion of a health
questionnaire, neurologic examination, and neuropsychologic evaluation. An
exposure index was calculated for each worker based on level and duration
of exposure in the potroom, where exposures were the greatest. This index
was correlated with symptoms, signs, and neuropsychologic test scores.
RESULTS--Twenty-two (88%) of the patients reported frequent loss of
balance, and 21 (84%) reported memory loss. Neurologic examination revealed
signs of incoordination in 21 (84%) of the patients. Neuropsychologic test
results showed preservation in certain spheres of functioning, such as
verbal IQ, with substantial impairment in others, particularly memory
functioning. On memory tests, 70% to 75% showed mild or greater impairment.
The majority (17 of 19 tested, or 89%) showed depression on the Minnesota
Multiphasic Personality Inventory. The exposure index was significantly
correlated with signs and symptoms of incoordination. CONCLUSIONS--This
study and others in humans and animals support the existence of a syndrome
characterized by incoordination, poor memory, impairment in abstract
reasoning, and depression. Aluminum exposure in the potroom seems the most
likely cause.
