A high prevalence of an atypical levodopa-resistant parkinsonism has been reported in the Caribbean island of Guadeloupe. These seminal observations have not been replicated or extended to neighbouring populations who share genetic and environmental characteristics. To further characterise this atypical parkinsonism we prospectively investigated 305 consecutive patients with neurodegenerative parkinsonism in a community-based population from Guadeloupe and Martinique, a neighbouring French Caribbean island where the population has similar environmental and genetic backgrounds. The aims of this study were to confirm the frequency of atypical parkinsonism within this cohort and to precisely define its clinical phenotype. A high frequency (66%) of atypical parkinsonism was identified in both Guadeloupe and Martinique. The clinical phenotype consisted of a levodopa-resistant parkinsonism with postural instability (72%), early dementia (58%), dysautonomia (58%), rapid-eye-movement sleep behavioural disorder (53%), hallucinations (43%), and supranuclear gaze palsy (29%). A low educational level was identified as a major risk factor for developing atypical parkinsonism (p < .001). Our findings support the existence of a distinctive atypical parkinsonism - Caribbean Parkinsonism - within the French Caribbean Islands. This could either correspond to a single entity or reflect a propensity for developing more widespread and rapidly progressive lesions in Caribbean patients with parkinsonism. In both cases, genetic susceptibility and/or environmental exposure may be involved.
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