Study of the prevalence of Parkinson's disease using dopamine transporter imaging
ABSTRACT To investigate the prevalence of Parkinson's disease (PD), a three-phase study was conducted.
In phase 1, standardized interviews were performed in a random sample of elderly aged 65 years or older using a questionnaire. In phase 2, neurological examinations were performed to clinically diagnose PD. In phase 3, dopamine transporter (DAT) imaging was performed to support the clinical diagnosis. After the three-phase study, longitudinal clinical observation was performed.
A total of 714 subjects participated in the phase-1. Two hundred and twenty-two subjects, scored more than two points, were referred to the movement disorder specialist. Eighteen of these subjects showed overt or equivocal Parkinsonian features. Three subjects were clinically diagnosed with possible PD: five with essential tremor with equivocal extrapyramidal signs, eight with frontal-subcortical gait disorder and two with drug-induced Parkinsonism. The three subjects with possible PD showed a typical PD pattern of reduced DAT density. DAT density was normal in the other 15 subjects. Results of long-term follow-up supported the diagnoses. The crude prevalence of PD was 0·42 per 100 persons.
During the clinical evaluation, we encountered a very large proportion of subjects with equivocal Parkinsonian features, who posed a diagnostic challenge and a substantial risk of misestimating the prevalence of PD. The combination of DAT imaging and longitudinal clinical observation of equivocal cases enabled us to differentiate PD from other conditions. We suspect that the variation in estimates of the prevalence of PD may be attributable to a considerable proportion of subjects with equivocal Parkinsonian features and how they are evaluated.
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ABSTRACT: Essential tremor (ET) is one of the most common movement disorders. The prevalence of ET varies substantially among studies. In Korea, there is no well-designed epidemiological study of the prevalence of ET. Thus, we investigated the prevalence of ET in a community in Korea. Standardized interviews and in-person neurological examinations were performed in a random sample of the elderly aged 65 yr or older. Next, movement specialists attempted to diagnose ET clinically. People who showed equivocal parkinsonian features underwent dopamine transporter imaging using [(123)I]-FP-CIT SPECT, to differentiate ET from parkinsonism. A total of 714 subjects participated in this population-based study. Twenty six of these subjects were diagnosed as having ET. The crude prevalence of ET was 3.64 per 100 persons. Age, gender, or education period were not different between the ET patients and the non-ET subjects. The prevalence of ET was slightly lower than those reported in previous studies. Further studies including more subjects are warranted.Journal of Korean Medical Science 12/2014; 29(12):1694-8. DOI:10.3346/jkms.2014.29.12.1694 · 1.25 Impact Factor
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ABSTRACT: Parkinson's Disease (PD) is a common neurodegenerative disorder. We sought to synthesize studies on the prevalence of PD to obtain an overall view of how the prevalence of this disease varies by age, by sex, and by geographic location. We searched MEDLINE and EMBASE for epidemiological studies of PD from 1985 to 2010. Data were analyzed by age group, geographic location, and sex. Geographic location was stratified by the following groups: 1) Asia, 2) Africa, 3) South America, and 4) Europe/North America/Australia. Meta-regression was used to determine whether a significant difference was present between groups. Forty-seven studies were included in the analysis. Meta-analysis of the worldwide data showed a rising prevalence of PD with age (all per 100,000): 41 in 40 to 49 years; 107 in 50 to 59 years; 173 in 55 to 64 years; 428 in 60 to 69 years; 425 in 65 to 74 years; 1087 in 70 to 79 years; and 1903 in older than age 80. A significant difference was seen in prevalence by geographic location only for individuals 70 to 79 years old, with a prevalence of 1,601 in individuals from North America, Europe, and Australia, compared with 646 in individuals from Asia (P < 0.05). A significant difference in prevalence by sex was found only for individuals 50 to 59 years old, with a prevalence of 41 in females and 134 in males (P < 0.05). PD prevalence increases steadily with age. Some differences in prevalence by geographic location and sex can be detected. © 2014 International Parkinson and Movement Disorder SocietyMovement Disorders 11/2014; 29(13). DOI:10.1002/mds.25945 · 5.63 Impact Factor