Epidemiology of primary focal dystonias in the western area of Tottori prefecture in Japan: Comparison with prevalence evaluated in 1993.

An epidemiological survey of primary focal dystonias in the western area of Tottori Prefecture in Japan was conducted in 2003, and the results were compared with those of a previous survey in 1993. The service-based prevalence of primary focal dystonia was 13.7 per 100,000 population, representing an increase from that found in the 1993 survey. In 1997, botulinum toxin type A was approved for use in Japan to treat blepharospasm, and the increased number of patients now being evaluated and diagnosed with focal dystonias at medical centers throughout Japan may be responsible for this increased prevalence. Prevalence by subtype per 100,000 population was as follows: facial dystonia, 6.5; spasmodic torticollis, 2.0; writer's cramp, 4.4; and other focal dystonias; 0.8. Facial dystonia showed the most marked increase in service-based prevalence among these subtypes.     

Prevalence of dystonia in Akita Prefecture in Northern Japan.

We investigated the prevalence of dystonia in Akita Prefecture (population was 1,166,967 as of 1 November 2004). The prevalence of primary generalized and focal dystonia is estimated to be 0.68 and 14.4 per 100,000 persons, respectively. Blepharospasm is the most common primary dystonia in this area.     

Prevalence of primary focal and segmental dystonia in Oslo

All patients seeking medical treatment for primary focal and segmental dystonia in Oslo, Norway, were identified in a service-based prevalence study. A total of 129 patients with focal and segmental dystonia were treated. The total prevalence was 25.4 per 100,000, but the prevalence increased with age from 4.1 (age < 30) to 58.7 (age > 70). The prevalence in subjects of European descent was 28.3 per 100,000, much higher than among first-generation immigrants of Asian and African descent.     

Service-based survey of dystonia in munich

We performed a service-based epidemiological study of dystonia in Munich, Germany. Due to favourable referral and treatment patterns in the Munich area, we could provide confident data from dystonia patients seeking botulinum toxin treatment. A total of 230 patients were ascertained, of whom 188 had primary dystonia. Point prevalence ratios were estimated to be 10.1 (95% confidence interval 8.4-11.9) per 100,000 for focal and 0.3 (0.0-0.6) for generalised primary dystonia. The most common focal primary dystonias were cervical dystonia with 5.4 (4.2-6.7) and essential blepharospasm with 3.1 (2.1-4.1) per 100,000 followed by laryngeal dystonia (spasmodic dysphonia) with 1.0 (0.4-1.5) per 100,000.     

Prevalence of multiple sclerosis in Belgrade, Yugoslavia

OBJECTIVES: To estimate the distribution of multiple sclerosis in the Belgrade population. METHODS: All persons who were affected and/or died from multiple sclerosis (Poser's criteria), with residence in the Belgrade region had been collected from January 1, 1985 to December 31, 1996. Prevalence was adjusted by direct method, using world population. RESULTS: From 1985 to 1996, 823 patients were suffering from multiple sclerosis. Sex ratio was 1:1.9. The mean age at onset was 32.2 +/- 9.8 years. A relapsing-remitting course of multiple sclerosis was reported in 50.7% patients, secondary progressive in 36.4%, patients, and primary progressive in 12.9% patients. On December 31, 1996, age-adjusted prevalence of multiple sclerosis in Belgrade was 41.5/100,000, 28.2/100,000 for males, and 54.1/100,000 for females. During the period studied, statistically highly significant increasing trend of multiple sclerosis prevalence was observed (P = 0.0001). CONCLUSIONS: According to findings presented in this study, Belgrade is an area with high prevalence of multiple sclerosis.     

Epidemiology of focal and generalized dystonia in Rochester, Minnesota

The epidemiology of generalized and focal dystonias was investigated in the Rochester, Minnesota, population over the period 1950-1982. The crude incidence of generalized dystonia was 2 per million persons per year, and for all focal dystonias combined, 24 per million per year. The crude prevalence rate was 34 per million persons for generalized dystonia and 295 per million persons for all focal dystonias. Torticollis was the most common focal dystonia; essential blepharospasm, oromandibular dystonia, spasmodic dysphonia, and writer's cramp were less common and had roughly equal incidence and prevalence rates.     

The prevalence of primary dystonia in the general community

The prevalence of primary dystonia was assessed in a random population sample of individuals aged 50 and over in Bruneck, South Tyrol. The diagnosis of primary dystonia was confirmed by videotaped review. Primary dystonia was present in 6 of 707 cases resulting in a prevalence rate of 732 per 100,000 (95% CI 319-1,564) in the general population aged 50 and over. Only two cases (33%) had been previously diagnosed. These results indicate that the true prevalence of primary dystonia is significantly higher than published rates.     

Prevalence and diagnostic challenge of dystonia in Thailand: a service-based study in a tertiary university referral centre

Although the subspeciality of movement disorders was established in neurology more than 20 years ago, it is relatively new in Thailand, and while most physicians are generally aware of Parkinson's disease, they often are not familiar with dystonia. As one of the common movement disorders seen in general practice, a number of family and population studies have suggested that as many as two-thirds of patients with dystonia may be underdiagnosed and it is likely that misdiagnosis occurs frequently. Moreover, there is little information on the prevalence of dystonia in Thailand. The purpose of this study was to determine the prevalence and clinical profile of dystonia among Thai patients who came from the southern part of Bangkok, which is in the catchment area of Chulalongkorn University Hospital. In addition, the diagnostic accuracy of dystonia among referred patients was assessed. The medical records of 207 patients were reviewed and it was determined that a large proportion of them (71.9%) had focal dystonia with cervical dystonia being the most common form. Primary dystonia (68.1%) accounted for the majority of the cases. The prevalence of all forms of dystonia, primary dystonia and focal dystonia was 19.9, 13.6 and 14.3 per 100,000 persons, respectively. The diagnostic accuracy of dystonia among referred patients was 85.5%. The most common misdiagnosis was cervical spondylosis, followed by myofascial pain syndrome. Most patients had an average disease duration of 4 years before dystonia was finally diagnosed. Most patients with focal dystonia responded well to botulinum toxin therapy, with 13.3% suffering only mild transient adverse events. In spite of the limitations of this study, this data will initiate a process of increasing both patient and professional awareness of dystonia in Thailand.     

The prevalence of primary dystonia: A systematic review and meta‐analysis

Dystonia is a hyperkinetic movement disorder characterized by sustained muscle contractions that produce repetitive movements and abnormal postures. Specific information on the prevalence of dystonia has been difficult to establish because the existing epidemiological studies of the condition have adopted different methodologies for case ascertainment, resulting in widely differing reported prevalence. Medline and Embase databases were searched using terms specific to dystonia for studies of incidence, prevalence, and epidemiology. All population‐based studies reporting an incidence and/or prevalence of primary dystonia were included. Sixteen original studies were included in our systematic review. Fifteen studies reported the prevalence of dystonia, including 12 service‐based and three population‐based studies. We performed a meta‐analysis on the results of the service‐based studies, and were able to combine data on the prevalence of several dystonia subtypes. From these studies, we calculated an overall prevalence of primary dystonia of 16.43 per 100,000 (95% confidence interval [CI]: 12.09–22.32). The prevalence of dystonia reported in the three population‐based studies appears higher than that reported in the service‐based studies. Only 1 of the 16 studies reported an incidence of cervical dystonia. This corresponded to a corrected incidence estimate of 1.07 per 100,000 person‐years (95% CI: 0.86–1.32). Despite numerous studies on the epidemiology of dystonia, attempting to determine an accurate prevalence of the condition for health services planning remains a significant challenge. Given the methodological limitations of the existing studies, our own prevalence estimate of primary dystonia likely underestimates the true prevalence of the condition. © 2012 Movement Disorder Society     

Community survey of primary dystonia in the city of Kolkata, India.

An epidemiological study on dystonia has not been reported from India. As part of a major study to find out the prevalence of major neurological disorders in the large urban city of Kolkata, Eastern India, we planned to determine the prevalence of primary dystonia. The study design was a cross-sectional study of a sample population obtained through stratified random selection and conducted in a two-stage procedure of screening by a nonprofessional team followed by confirmation of screened positive cases by the study neurologist. A total population of 52,377 was screened, and 29 subjects with dystonia were diagnosed. Out of them 23 subjects had primary dystonias [crude prevalence rate (CPR), 43.91/100,000; 95% confidence interval (CI), 28.41-64.81; age-standardized rates to world standard population, 49.06 (95% CI,31.74-72.41)] and all cases were focal type and predominantly of limb dystonia variety. Mean onset of dystonias were earlier in women (43.5 years) as compared to men (46.6 years). Thus our study on primary dystonia shows higher prevalence when compared with that of many studies globally, predominantly of focal type, earlier onset among women, and more cases of limb dystonias when compared with more prominent blepharospasm and cervical dystonias in western reports.     

Epidemiology of myotonic dystrophy type 1 (Steinert disease) in Belgrade (Serbia)

The aim of this study was to estimate the incidence and prevalence of myotonic dystrophy type 1 (DM1) in Belgrade during the period 1983–2002.

The patients who had DM1 were ascertained through hospital records from all neurological departments in Belgrade during 1983–2002. The molecular genetic analysis was performed in all patents included in the study.

We identified 101 DM1 patients (52 males and 49 females). The average annual incidence rate of DM1 in Belgrade for the period observed was 2.0/1,000,000 (95% confidence interval (CI), 0.3–8.3), 2.1/1,000,000 (95% CI, 0.3–8.3) for males and 2.0/1,000,000 (95% CI, 0.3–8.3) for females. The highest age-specific DM1 incidence was registered in the age group 20–49: 3.4/1,000,000 (95% CI, 0.5–7.6), 4.0/1,000,000 (95% CI, 1.1–10.2) in males and 2.5/1,000,000 (95% CI, 0.5–7.6) in females. In the population of Belgrade, a cumulative probability of acquiring DM1 was 1 per 8621 for men and 1 per 9259 for women (1 per 8940 of the population for both sexes). The prevalence of DM1 in Belgrade on 31 December 2002 was 5.3/100,000 (95% CI, 4.2–6.6).     

Prevalence of chronic inflammatory demyelinating polyneuropathy in New South Wales, Australia

A prevalence study of chronic inflammatory demyelinating polyneuropathy (CIDP) was performed in New South Wales (NSW), Australia, with a prevalence day of August 6, 1996, which coincided with a national census. The population of NSW was 5,995,544, and the crude prevalence of CIDP was 1.9 per 100,000 population. It was higher in male patients than in female patients, and the age-specific prevalence reached a maximum of 6.7 per 100,000 population in the 70- to 79-year-old age group. The prevalence in the city of Newcastle, with a population of 448,663, was 2.0 per 100,000 population and is representative of the whole of NSW. The estimated crude annual incidence was 0.15 per 100,000 population. The mean age of onset was 47.6 years (median, 53.5 years), 51% of patients had a relapsing-remitting course, the mean duration on prevalence day was 7.1 years (median, 5 years), and 87% of patients were able to walk without walking aids or other assistance.     

Epidemiological and clinical characteristics of ALS in Belgrade, Yugoslavia

We present the results of the first epidemiological study of ALS in Belgrade. The distribution of 58 newly discovered cases in a 7-year survey period (1985–1991) showed that the average annual age-adjusted incidence rate was 0.42 per 100,000 population (95% confidence interval, 0.18–0.83). The rate for males was 1.5 times higher than the rate for females. The greatest age-specific average incidence rate was observed in patients between 60 and 64 (3.66 per 100,000 population; 95% confidence interval, 2.17–5.78). The actual age-adjusted prevalence rate on December 31, 1991 was 1.07 per 100,000 (95% confidence interval, 0.71–1.71). The mean age at onset of the disease was 56.2 ± 9.8 and it ranged from 24 to 74. We studied the natural course of the disease through the mean duration and cumulative probability of survival. The mean duration of the disease was 27.7 ± 18.2 months. The cumulative probability of survival was 27% for the whole population in a 5-year interval. Elderly patients and those with bulbar signs at onset had a poorer prognosis. Patients under 49 at onset and those with the spinal form of the disease survived longer.     

Prevalence study of primary dystonia in Iceland.

In Iceland, the crude prevalence for all types of primary dystonia was 37.1/10(5) (confidence interval, 30.4-44.9). Focal dystonia had the highest prevalence (31.2/10(5)), followed by segmental (3.1/10(5)), multifocal (2.4/10(5)) and generalized dystonia (0.3/10(5)). Cervical dystonia was the most common focal dystonia (11.5/10(5)), followed by limb dystonia (8.0/10(5)), laryngeal dystonia (5.9/10(5)), blepharospasm (3.1/10(5)), and oromandibular dystonia (2.8/10(5)). The male:female ratio for all patients was 1:1.9 (P=0.0007), and females outnumbered males in all subtypes except oromandibular dystonia. Mean age of onset for all patients was 42.7 years (range, 3-82 years). This prevalence of primary dystonia is higher than in most reported studies, possibly because of more complete ascertainment but the relative frequencies of dystonia subtypes is similar.     

Epidemiology of primary dystonias in Japan: comparison with Western countries.

We performed epidemiological studies of primary dystonia in the city of Kyoto. The prevalence was at least 10.1 per 100,000 persons, which was similar to that in Western countries. Facial dystonia was more common than other types, which contrasts with that reported in Europe. Age of onset for both genders was in agreement with that in other countries.     

The natural history of sex-linked recessive dystonia parkinsonism of Panay,Philippines (XDP)

Sex-linked dystonia parkinsonism (XDP) was reported by Lee et al. in 1975 occurring endemically in Panay, Philippines. It is an adult onset, sex-linked, predominantly male, severe, progressive movement disorder with high penetrance and a high frequency of generalization. The movement disorder is characterized by dystonic movements usually starting in the third or fourth decade, focal at the onset, spreading to generalization within 2-5 years. The dystonia co-exist or is replaced by parkinsonism usually beyond the 10th year of illness. As of June 2001, 376 XDP cases have been registered. One hundred and fifteen cases have died. The prevalence of XDP in the island of Panay is 5.24 per 100,000; 0.34/100,000 in the general population. The prevalence varies in the different provinces; it is highest in Capiz at 18.88/100,000, 7.46/100,000 in Aklan, 1.28 in Iloilo and 0.83 in Antique. The 376 cases are from 188 families and 92% of cases have positive family history. Ninety-nine percent of the cases are males. The mean age of onset is 39.48 years. Duration of illness is 12.95 years. Ninety-four percent of patients initially manifest with dystonic symptoms, while only 6% present with Parkinsonian traits. Among those presenting with dystonia, the initial presentation is in the lower extremities in 33%, craniofacial in 27%, cervical and shoulder in 25%, upper extremities in 14%, and trunk in 1%. Regardless of the site of onset, the dystonia spreads in 98% and generalizes within 5 years in 84%. Neuroimaging (magnetic resonance imaging, MRI) was done in 16 patients. In the patients who have just manifested the disease usually when dystonia predominates and parkinsonism is absent. MRI showed minimal atrophy of the caudate and putamen or subtle putaminal signal abnormality. In the late course, where Parkinsonism predominates, severe atrophy of the caudate and putamen as well as marked increase in signal abnormality are seen. There are six autopsied cases of XDP. Neuropathology revealed marked atrophy of the caudate and putamen mostly in the cases with longstanding illness. The sex-linked pattern of inheritance has been established. Genetic studies have located the affected gene (DYT3) to Xq13.1. Nemeth's group has mapped the XDP gene to a <350 kb locus in the DXS 7117-DX 559 region. To date, no treatment has been proven consistently effective.     

An epidemiologic investigation of amyotrophic lateral sclerosis in Jefferson County, Missouri, 1998-2002

Amyotrophic lateral sclerosis (ALS) cases diagnosed between 1998 and 2002 were identified to study ALS prevalence and spatial clustering in Jefferson County, Missouri, where an active lead smelter is located. The study used the El Escorial criteria for ALS diagnosis, the capture-recapture analysis for ALS case ascertainment, and the spatial scan statistic for cluster analysis. The estimated crude prevalence of ALS in Jefferson County was 3.9 per 100,000 population (95% CI, 1.7-7.7) at the time point on December 31, 2002. After age-adjustment to the 2002 U.S. population, the prevalence was 4.2 per 100,000 (95% CI, 1.9-6.6). This prevalence estimate was comparable to recent prevalence estimates from Western Europe. A small but significant cluster (p=0.04) was detected around the smelter area. An ALS registry utilizing outpatient, inpatient, and death certificate data is needed to provide comprehensive information for ALS case ascertainment. Etiologic studies are needed to assess whether living in proximity to a lead smelter is associated with the development of ALS.     

Epidemiology of primary dystonia

The prevalence estimates for primary dystonia range from two to 50 cases per million for early-onset dystonia and from 30 to 7320 cases per million for late-onset dystonia. From analysis of methodological information from 14 selected studies, we concluded that all studies on the basis of treatment settings or record-linkage systems, and two population-based surveys were probably flawed by incomplete ascertainment; the third population-based study provided the largest prevalence for late-onset dystonia but probably overestimated the prevalence of the disorder. Age and ethnic differences among study populations further biased comparisons of estimates. On the basis of methodologically more robust service-based studies and the likely percentage of underdiagnosis in a given area, more accurate prevalence estimates may be 111 per million for early-onset dystonia in Ashkenazi Jews from New York area, 600 per million for late-onset dystonia in northern England, and 3000 per million for late-onset dystonia in the Italian population over age 50 years.     

Multiple sclerosis in the Cambridge health district of east Anglia.

A survey of multiple sclerosis (MS) in the Cambridge Health District has identified 374 cases in a population of 288,410, giving a prevalence of 130 per 100,000. A total of 322 cases (86%) had either clinically definite or probable multiple sclerosis on 1 July 1990 (112 per 100,000) and 52 cases (14%) had suspected multiple sclerosis (18 per 100,000.) The incidence during 1989-91 was 5.94 per 100,000 per year. The prevalence figure is higher than in recent surveys from other southern parts of the United Kingdom, but correction for the age and sex characteristics of the at risk population eliminates these differences. The overall prevalence of multiple sclerosis is probably between 108 and 120 per 100,000 in the southern United Kingdom.     

Cases of dopa-responsive dystonia (Segawa disease) in Estonia

The aim of this report is to present the first four cases from three families of dopa-responsive dystonia diagnosed in Estonia. Diagnosis was performed by clinical evaluation and response to levodopa and was confirmed by gene analyses. The prevalence of dopa-responsive dystonia in Estonia was 1.4 per 100,000 (95%CI = 0.39–3.65) children less than 18 years of age. In all children with dystonia it is important to think about possible dopa-responsive dystonia as this is treatable condition and improving the quality of life of children.