title: Progression after chronic manganese exposure.
abstract: We report a longitudinal follow-up study on six patients with chronic manganese-induced parkinsonism following cessation of manganese exposure. Compared with the 1987 study, their parkinsonian symptoms showed a slow progression, particularly in gait disturbances such as freezing during turning and walking backward with retropulsion. The mean disability scores on the King's College Hospital Rating Scale were 15.0 +/- 4.2 in 1987 and 28.3 +/- 6.7 in 1991 (p = 0.003, paired t test). Review of the video records also confirmed a worsening of parkinsonism, especially in difficulty turning. Three of six patients receiving levodopa treatment had an initial improvement. The response decreased after 2 to 3 years. During the therapy, they did not develop on-off fluctuation or dyskinesia. We conclude that patients with manganese-induced parkinsonism may develop increasing neurologic dysfunction long after cessation of exposure and that their responses to levodopa are different from those of patients with Parkinson's disease.
authors.affiliation: Department of Neurology, Chang Gung Medical College and Memorial Hospital, Taipei, Taiwan.
authors.forename: C C
authors.initials: CC
authors.lastname: Huang
authors.forename: C S
authors.initials: CS
authors.lastname: Lu
authors.forename: N S
authors.initials: NS
authors.lastname: Chu
authors.forename: F
authors.initials: F
authors.lastname: Hochberg
authors.forename: D
authors.initials: D
authors.lastname: Lilienfeld
authors.forename: W
authors.initials: W
authors.lastname: Olanow
authors.forename: D B
authors.initials: DB
authors.lastname: Calne
mesh_terms: D000328:Adult; D002908:Chronic Disease; D005500:Follow-Up Studies; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008345:Manganese / Q000009:adverse effects*; D008875:Middle Aged; D009069:Movement Disorders / Q000209:etiology; D009422:Nervous System Diseases / Q000139:chemically induced; D016273:Occupational Exposure; D010302:Parkinson Disease, Secondary / Q000139:chemically induced* / Q000188:drug therapy
chemical_list: D008345:Manganese; D007980:Levodopa