LONG-TERM PROGRESSION IN CHRONIC MANGANISM - 10 YEARS OF FOLLOW-UP

We studied the long-term clinical course of five patients with chronic manganese intoxication. The mean scores of the King's College Hospita l Rating Scale for Parkinson's disease increased from 15.0 +/- 4.2 in 1987 to 28.3 +/- 6.70 in 1991 and then to 38.1 +/- 12.9 in 1995. The d eterioration was most prominent in gait, rigidity, speed of foot tappi ng, and writing. Tissue concentrations of manganese in blood, urine, s calp hair, and pubic hair returned to normal. Follow-up MRIs did not s how paramagnetic high-signal intensity on T1-weighted images. The data indicate that clinical progression in patients with manganese parkins onism continues even 10 years after cessation of exposure.