Sex Differences in Dystonia.

BACKGROUND: Prior studies have indicated that female individuals outnumber male individuals for certain types of dystonia. Few studies have addressed factors impacting these sex differences or their potential biological mechanisms. OBJECTIVES: To evaluate factors underlying sex differences in the dystonias and explore potential mechanisms for these differences. METHODS: Data from individuals with various types of dystonia were analyzed in relation to sex. Data came from two different sources. One source was the Dystonia Coalition database, which contains predominantly idiopathic adult-onset focal and segmental dystonias. The second source was the MDSGene database, which contains predominantly early-onset monogenic dystonias. RESULTS: The 3222 individuals from the Dystonia Coalition included 71% female participants and 29% male participants for an overall female-to-male ratio (F:M) of 2.4. This ratio varied according to body region affected and whether dystonia was task-specific. The female predominance was age-dependent. Sex did not have a significant impact on co-existing tremor, geste antagoniste, depression or anxiety. In the 1377 individuals from the MDSGene database, female participants outnumbered male participants for some genes (GNAL, GCH1, and ANO3) but not for other genes (THAP1, TH, and TOR1A). CONCLUSIONS: These results are in keeping with prior studies that have indicated female individuals outnumber male individuals for both adult-onset idiopathic and early onset monogenic dystonias. These results extend prior observations by revealing that sex ratios depend on the type of dystonia, age, and underlying genetics.

Gender Differences in Task Specific Dystonia: What Can we Learn from Musician's Dystonia?

BACKGROUND: Musician's Dystonia (MD) is a task specific, focal dystonia which usually occurs only at the instrument. The pathophysiology is not fully understood, but several risk factors like over-practice and genetic predisposition are known. Interestingly, 80% of those affected are men, which stands in contrast to the gender distribution in other focal dystonias, such as cervical dystonia. OBJECTIVES: Our aim was to evaluate the difference in women and men with regard to risk factors leading to MD. METHODS: We investigated known risk factors for MD in a large cohort of 364 MD patients by retrospectively collecting data on practice behavior and family history. RESULTS: In line with previous studies, we found a ratio of ~4:1 men to women. Age at onset of MD was significantly lower in women; however, subsequent analysis revealed that it was a positive family history (FH+) and not gender that was associated with a lower age at onset. Furthermore, we found that those with negative family history had accumulated more practice time until onset of MD. CONCLUSIONS: These results imply that the earlier age at onset in women did not depend on gender but was due to the higher proportion of a positive family history. In contrast, men were less likely to have a positive family history, suggesting that genetic factors may not be the primary reason for the higher prevalence of MD in men. Instead, differences in practice behaviors between men and women may contribute to this gender disparity.

Prevalence and temporal relationship of clinical co-morbidities in idiopathic dystonia: a UK linkage-based study.

While motor and psychiatric phenotypes in idiopathic dystonia are increasingly well understood, a few studies have examined the rate, type, and temporal pattern of other clinical co-morbidities in dystonia. Here, we determine the rates of clinical diagnoses across 13 broad systems-based diagnostic groups, comparing an overall idiopathic dystonia cohort, and sub-cohorts of cervical dystonia, blepharospasm, and dystonic tremor, to a matched-control cohort. Using the SAIL databank, we undertook a longitudinal population-based cohort study (January 1st 1994-December 31st 2017) using anonymised electronic healthcare records for individuals living in Wales (UK), identifying those diagnosed with dystonia through use of a previously validated algorithm. Clinical co-morbid diagnoses were identified from primary health care records, with a 10% prevalence threshold required for onward analysis. Using this approach, 54,166 dystonia cases were identified together with 216,574 matched controls. Within this cohort, ten of the main ICD-10 diagnostic codes exceeded the 10% prevalence threshold over the 20-year period (infection, neurological, respiratory, gastrointestinal, genitourinary, dermatological, musculoskeletal, circulatory, neoplastic, and endocrinological). In the overall dystonia cohort, musculoskeletal (aOR: 1.89, aHR: 1.74), respiratory (aOR: 1.84; aHR: 1.65), and gastrointestinal (aOR: 1.72; aHR: 1.6) disorders had the strongest associations both pre- and post-dystonia diagnosis. However, variation in the rate of association of individual clinical co-morbidities was observed across the cervical, blepharospasm, and tremor dystonia groups. This study suggests an increased rate of specific co-morbid clinical disorders both pre- and post-dystonia diagnosis which should be considered during clinical assessment of those with dystonia to enable optimum symptomatic management.

Oromandibular dystonia: from onset to spread a multicenter italian study.

BACKGROUND: Detailed information about the epidemiological and phenomenological differences among the aetiological subtypes of oromandibular dystonia (OMD) is lacking. Moreover, the OMD tendency to spread to other body sites has never been investigated. AIM: To compare the main demographic and clinical features of OMD in different aetiological groups and assess the risk of spread. MATERIALS AND METHODS: We retrospectively analysed data from patients contained in the Italian Dystonia Registry. The risk of spread was assessed by Kaplan Meyer curves and Cox regression analysis. RESULTS: The study included 273 patients (175 women) aged 55.7 years (SD 12.7) at OMD onset. Female predominance was observed. Idiopathic dystonia was diagnosed in 241 patients, acquired dystonia in 22. In 50/273 patients, dystonia started in the oromandibular region (focal OMD onset); in 96/273 patients the onset involved the oromandibular region and a neighbouring body site (segmental/multifocal OMD onset); and in 127/273 patients OMD was a site of spread from another body region. Sensory trick (ST) and positive family history predominated in the idiopathic group. No dystonia spread was detected in the acquired group, whereas spread mostly occurred within the first five years of history in 34% of the focal OMD onset idiopathic patients. Cox regression analysis revealed ST as a significant predictor of spread (HR, 12.1; 95% CI, 2.5 - 18.8; P = 0.002). CONCLUSION: This large study provides novel information about the clinical phenomenology of idiopathic and acquired OMD. We pointed out a possible role of oestrogens in favouring dystonia development. Moreover, we described for the first time the association between ST and dystonia spread, revealing possible common pathophysiological mechanisms. Our findings may be suggested as a referral point for future pathophysiological and therapeutic studies on OMD.

Does thyroid diseases contribute to the natural history of idiopathic adult-onset dystonia? Data from the Italian Dystonia Registry.

A few earlier observations and recent controlled studies pointed to the possible contribution of thyroid diseases in idiopathic adult-onset dystonia (IAOD). The aim of this study was to investigate the association between thyroid status and clinical characteristics of IAOD, focusing on dystonia localization, spread, and associated features such as tremors and sensory tricks. Patients were identified from those included in the Italian Dystonia Registry, a multicentre dataset of patients with adult-onset dystonia. The study population included 1518 IAOD patients. Patients with hypothyroidism and hyperthyroidism were compared with those without any thyroid disease. In the 1518 IAOD patients, 167 patients (11%; 95% CI 9.5-12.6%) were diagnosed with hypothyroidism and 42 (2.8%; 95% CI 1.99-3.74) with hyperthyroidism. The three groups were comparable in age at dystonia onset, but there were more women than men in the groups with thyroid disease. Analysing the anatomical distribution of dystonia, more patients with blepharospasm were present in the hyperthyroidism group, but the difference did not reach statistical significance after the Bonferroni correction. The remaining dystonia-affected body sites were similarly distributed in the three groups, as did dystonia-associated features and spread. Our findings provided novel information indicating that the high rate of thyroid diseases is not specific for any specific dystonia subpopulation and does not appear to influence the natural history of the disease.

Incidence and risk factors for secondary extralaryngeal dystonia in patients with laryngeal dystonia.

BACKGROUND AND OBJECTIVES: Laryngeal dystonia (LD) is a focal dystonia affecting adductor and/or abductor muscles of the larynx. It can be isolated or may spread to extra laryngeal muscles. The aim of this study was to report the characteristics of LD over time in a large single-center study with a long follow-up. METHODS: Retrospective review of patients with LD referred to our institution between 1991 and 2021. Demographic data, time to diagnosis, type of LD, follow-up and spread of dystonia [SD] were recorded. Risk factors for spread of dystonia during follow-up were analyzed. RESULTS: Over the 30-year period, 516 patients (77.3 % female, median age 50 years, range 5-87 years) were analyzed. Three hundred and fifteen patients (61 %) had adduction laryngeal dystonia, 136 patients (26.4 %) had abduction laryngeal dystonia, 46 patients (8.9 %) had adductor respiratory laryngeal dystonia, 12 patients (2.3 %) had mixed laryngeal dystonia, and seven patients (1.4 %) had singer's laryngeal dystonia. A previous history of dystonia was found in 47 patients (9.1 %). A laryngeal tremor was found in 68 patients (13.2 %). Since the onset of symptoms, LD was diagnosed after a median of 3 years (IQR: 1.0, 7.0). SD occurred in 55 patients (10.7 %) after a median time of 4 year (IQR: 1.5, 13.0). Patients with mixed laryngeal dystonia had higher probability of SD (p = 0.018). DISCUSSION: This study reports a large European study of LD, with a long follow-up. SD occurred in 10.5 % of patients. Patients with mixed laryngeal dystonia had a higher probability of SD. A close follow-up may be recommended for patients with mixed laryngeal dystonia.

Epidemiological and clinical aspects of a sample of Brazilian patients with primary dystonia and the impact of the new classification on their clinical evaluation / Aspectos epidemiológicos e clínicos de uma amostra de pacientes brasileiros com distonia primária e impacto da nova classificação em sua avaliação clínica

ABSTRACT Dystonia is a relatively common movement disorder but some of its epidemiological and clinical aspects have not been well characterized in Brazilian patients. Also, a new clinical classification for the disorder has been proposed and its impact on clinical practice is unclear. We aimed to describe the clinical and demographic characteristics of a Brazilian series of patients with primary dystonia, to estimate its local prevalence, and to explore the impact of using a new classification for dystonia. We identified 289 patients with primary dystonia over a 12-month period, of whom235 underwent a detailed evaluation. Patients with primary dystoniamade up one-sixth of all patients evaluated at the service where the study was conducted, with an estimated local prevalence of 19.8/100,000 inhabitants. The clinical and demographic characteristics of the patients were similar to those described elsewhere, with blepharospasm as the most common focal dystonia and most patients using sensory tricks that they judged useful on a day-to-day basis. The application of the new classification was easy and simple, and the systematic approach allowed for a better clinical characterization of our patients. We recognized two dystonic syndromes that were not described in the original article that proposed the classification, and suspected that the arbitrary distinction between generalized and multifocal dystonia seems not to be useful for patients with primary dystonia. In conclusion, the prevalence and clinical characteristics of our patients were not distinct from other studies and the new classification was shown to be practical and useful to characterize patients with dystonia.

RESUMO A distonia é um distúrbio de movimento relativamente comum e alguns de seus aspectos epidemiológicos e clínicos ainda não foram bem caracterizados em pacientes brasileiros. Além disso, uma nova classificação clínica para o transtorno foi proposta e seu impacto na prática clínica não é claro. Nosso objetivo é descrever as características clínicas e demográficas de uma série brasileira de pacientes com distonia primária, estimar sua prevalência local e explorar o impacto do uso de uma nova classificação para distonia. Foram identificados 289 pacientes com distonia primária (PDYS) durante um período de 12 meses, dos quais 235 foram submetidos a uma avaliação detalhada. Os pacientes com PDYS corresponderam a um sexto de todos os pacientes avaliados no serviço em que o estudo foi realizado, com uma prevalência local estimada de 19,8/100.000 habitantes. As características clínicas e demográficas dos pacientes foram semelhantes àquelas descritas em outros locais, com o blefaroespasmo como distonia focal mais comum e a maioria dos pacientes apresentando truques sensoriais que julgaram úteis no dia-a-dia. A aplicação da nova classificação foi fácil e simples, e a abordagem sistemática permitiu uma melhor caracterização clínica de nossos pacientes. Reconhecemos duas síndromes distônicas que não foram descritas no artigo original que propôs a classificação e suspeitamos que a distinção arbitrária entre distonia generalizada e multifocal parece não ser útil para pacientes com PDYS. Em conclusão, a prevalência e as características clínicas de nossos pacientes não foram distintas de outras amostras e a nova classificação mostrou-se prática e útil para caracterizar pacientes com distonia.