ArticlesPrevalence of progressive supranuclear palsy and multiple system atrophy: a cross-sectional study
Introduction
Progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) are two distinct and well described neurodegenerative disorders, but little is known about their prevalence in the general population. They are frequently misdiagnosed, especially as Parkinson's disease. Diagnosis of PSP and MSA may be especially difficult in the early stages of these diseases before atypical features have clearly emerged. Patients should ideally, therefore, be regularly reassessed by movement-disorder specialists.1 In the UK Parkinson's Disease Society Brain Bank, neuropathological assessment of 100 patients who died with a diagnosis of Parkinson's disease showed that around 6% actually had PSP and 5% MSA.2 Among 35 patients who had pathologically proven MSA, 55% of the 22 patients from institutions other than our own died with erroneous diagnoses of Parkinson's disease.3 From 1989 to 1994, 7·9% and 9·9% of 303 brains donated to the brain bank showed PSP and MSA, respectively (S Daniel, personal communication). However, patients with PSP and MSA are probably over-represented in studies of Parkinson's disease brain banks,4 and, therefore, estimates of prevalence made through extrapolation from these results may be misleading. Moreover, because survival in PSP and MSA is much shorter than that in Parkinson's disease, such data are better indicators of incidence than prevalence.
Prevalence studies of Parkinson's disease generally exclude atypical parkinsonian patients or include them under the diagnosis of parkinsonism.5, 6 We undertook a population-based study on the prevalence of parkinsonism and its different subtypes to estimate the prevalence of PSP and MSA.
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Patients and methods
We obtained ethics approval from the National Hospital for Neurology and Neurosurgery and the Institute of Neurology Joint Medical Ethics Committee.
Results
The total screened population was 121 608 people, of whom 23 859 were older than 55 years, and 14 272 older than 65 years. 679 patients were selected by screening, but 438 patients were excluded after review of records. Therefore, we studied 241 eligible patients. Patients were excluded because of: use of antiparkinsonian drugs for other indications (334 [76%] patients, 286 of whom had been receiving an anticholinergic in association with a dopamine antagonist for a psychiatric disorder); a
Discussion
With use of strict clinical diagnostic criteria, we assessed the population prevalence of PSP and MSA. Our results illustrate the importance of community-based studies, since none of the patients with PSP and only one with MSA were previously diagnosed. Initially, we used wide inclusion criteria so that as many patients as possible with potential parkinsonism could be identified. All patients were assessed by a neurologist with specialist experience in movement disorders, and almost all had a
References (27)
- et al.
“Mini-mental state”: a practical method for grading the cognitive state of patients for the clinician
J Psychiatr Res
(1975) - et al.
Accuracy of clinical diagnosis in parkinsonism: a prospective study
Can J Neurol Sci
(1991) - et al.
What features improve the accuracy of clinical diagnosis in Parkinson's disease: a clinicopathologic study
Neurology
(1992) - et al.
Clinicopathological study of 35 cases of multiple system atrophy
J Neurol Neurosurg Psychiatry
(1995) - et al.
Potential bias in autopsy series of Parkinson's disease and related disorders
Neurology
(1998) - et al.
The epidemiology of Parkinson's-disease in the county of Rogaland. Norway
Mov Disord
(1995) - et al.
Prevalence of Parkinson's disease and other types of parkinsonism: a door-to-door survey in three Sicilian municipalities—The Sicilian Neuro-Epidemiologic Study (SNES) Group
Neurology
(1992) - et al.
Neurological disease in a defined population: the results of a pilot study in two general practices
Neuroepidemiology
(1996) - et al.
Neuroepidemiology in the United Kingdom
J Neurol Neurosurg Psychiatry
(1993) - et al.
Clinical research criteria for the diagnosis of progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome): report of the NINDS-SPSP international workshop
Neurology
(1996)