Occupational Dystonia Research Articles

Clinical Features of Common Types of Dystonia and Practical Approach for Occupational Dystonia

Dystonia is a movement disorder characterized by sustained muscle contractions that result in abnormal "patterned" movements and/or postural abnormalities. Based on the accompanying symptoms, dystonia can be classified as isolated (i.e., with dystonia only), combined (i.e., with other movement disorders such as myoclonus), or complex (i.e., with symptoms other than movement disorders such as mental retardation). Moreover, dystonia may affect single or multiple parts of the body and accordingly be classified as focal, segmental, multifocal, hemi, or generalized. The most common type of dystonia is isolated focal dystonia, often accompanied with a specific action (task-specific action). The "task-specificity" uniquely illustrates the nature of dystonia, and this phenomenon is most clearly observed in occupation-related dystonias that include musician's and athlete's dystonia. In this article, we first elucidate the general issues of common focal dystonia (cervical dystonia, blepharospasm, and focal hand dystonia) and then present several educational cases of occupational (task-specific) dystonia with some clinical pearls for practical management.

Task-specific dystonia in hairdressers: a questionnaire survey and review of the literature.

Hairdresser dystonia is one of the occupational dystonias and task-specific movement disorders occurring as a result of long-term repetitive cutting with scissors. The task-specific dystonia manifests itself as a loss of voluntary motor control during extensive practice of cutting requiring a high level of technical proficiency. The prevalence rate of hairdresser dystonia is not well-known worldwide. A questionnaire regarding dystonia was prepared for hairdressers. After sending the questionnaires to 800 hairdressers by direct mail, 134 answers were received by mail. Five of the 134 were suspected to have hairdresser-associated focal dystonia. Thus, 3.7% of hairdressers might have task-specific dystonia. This report was limited because of the small number of participants. However, this research is valuable because it was difficult to find a patient with suspected dystonia due to concerns related to job security.

Dealer’s Dytonia (Croupier’s Cramp) – An Unusual Hazard Of Gambling

Dystonia takes many forms and often presents acutely to emergency care. The diagnosis is often delayed because it mimics other more common conditions. This report describes a patient with a rare occupational dystonia, the typical clinical features of dystonia in general, and differentials to consider.

Personality traits of Japanese patients with focal dystonia-Variable classification by affected body part and occupation

We administered the Revised Neo Personality Inventory (NEO-PI-R) to 92 Japanese patients with focal dystonia and analyzed the relation of their personality traits, affected body parts, and occupations using a decision tree method. Results show that participants' personality traits were related to their occupation rather than the body part. Occupational dystonia patients including musicians exhibited neurotic tendencies and a high level of anxiety. Moreover, patients with occupational upper limb dystonia had realistic thinking patterns. Patients with musicians' dystonia were open about their emotional experiences: both positive and negative.

Safety and long-term efficacy of ventro-oral thalamotomy for focal hand dystonia: A retrospective study of 171 patients.

ObjectiveTo report the safety and long-term efficacy of ventro-oral thalamotomy for 171 consecutive patients with task-specific focal hand dystonia.MethodsBetween October 2003 and February 2017, 171 consecutive patients with task-specific focal hand dystonia underwent unilateral ventro-oral thalamotomy. Etiologies included writer's cramps (n = 92), musician's dystonias (n = 58), and other occupational task-related dystonias (n = 21). The task-specific focal hand dystonia scale was used to evaluate patients' neurologic conditions (range 1–5, high score indicated a better condition). The scores before surgery; at 1 week, 3 months, and 12 months postoperatively; and the last available follow-up period were determined. Postoperative complications and postoperative recurrence were also evaluated.ResultsThe scores before surgery; at 1 week (1.72 ± 0.57, 4.33 ± 0.85 [p < 0.001]), 3 months (4.30 ± 1.06 [p < 0.001]), and 12 months (4.30 ± 1.13 [p < 0.001]); and the last available follow-up (4.39 ± 1.07 [p < 0.001]) postoperatively improved. The mean clinical follow-up period was 25.4 ± 32.1 months (range: 3–165). Permanent adverse events developed in 6 patients (3.5%). Eighteen patients developed recurrent dystonic symptoms postoperatively. Of these 18 patients, 9 underwent ventro-oral thalamotomy again, of which 7 achieved improvement.ConclusionVentro-oral thalamotomy is a feasible and reasonable treatment for patients with refractory task-specific focal hand dystonias. Prospective, randomized, and blinded studies are warranted to clarify more accurate assessment of the safety and efficacy of ventro-oral thalamotomy for task-specific focal hand dystonia.Classification of evidenceThis study provides Class IV evidence that for patients with task-specific focal hand dystonia, ventro-oral thalamotomy improves dystonia.

Clinical and Phenomenological Characteristics of Patients with Task-Specific Lingual Dystonia: Possible Association with Occupation.

Lingual dystonia is a subtype of oromandibular dystonia, which is a movement disorder characterized by involuntary sustained or intermittent contraction of the masticatory and/or tongue muscles. Lingual dystonia interferes with important daily activities, such as speaking, chewing, and swallowing, resulting in vocational and social disability. The aim of this study was to investigate a possible relationship between occupation and the development of lingual dystonia. Phenomenological and clinical characteristics of 95 patients [53 females (55.8%) and 42 males (44.2%), mean age 48.0 years] with task-specific, speech-induced lingual dystonia were analyzed. Structured interviews were carried out to obtain information regarding primary occupation, including overtime work and stress during work. The factors that might have influenced the development of lingual dystonia were estimated using multivariate logistic regression analysis of the 95 patients with lingual dystonia and 95 controls [68 females (71.6%) and 27 males (28.4%), mean age 47.2 years] with temporomandibular disorders. Overall, 84.2% of the patients had regular occupations; 73.8% of the patients with regular occupations reported working overtime more than twice a week, and 63.8% of them experienced stress at the workplace. Furthermore, 82.1% of the patients had engaged in occupations that required them to talk to customers or other people under stressful situations over prolonged periods of time for many years (mean: 15.6 years). The most common occupation was sales representative (17.9%), followed by telephone operator (13.7%), customer service representative (10.5%), health care worker (9.5%), waiter or waitress (5.3%), receptionist (5.3%), and cashier (5.3%). Twenty-nine patients (30.5%) had tardive lingual dystonia. Logistic regression analyses revealed that frequent requirements for professional speaking (p = 0.011, odds ratio: 5.66), high stress during work (p = 0.043, odds ratio: 5.4), and neuroleptic use (p = 0.032, odds ratio: 2.52) were significant contributors to the manifestation of lingual dystonia. Professions in which conversations in stressful situations are unavoidable may trigger lingual dystonia. Therefore, speech-induced lingual dystonia can be regarded as occupational dystonia in certain cases.

How Many Dystonias? Clinical Evidence.

Literary reports on dystonia date back to post-Medieval times. Medical reports are instead more recent. We review here the early descriptions and the historical establishment of a consensus on the clinical phenomenology and the diagnostic features of dystonia syndromes. Lumping and splitting exercises have characterized this area of knowledge, and it remains largely unclear how many dystonia types we are to count. This review describes the history leading to recognize that focal dystonia syndromes are a coherent clinical set encompassing cranial dystonia (including blepharospasm), oromandibular dystonia, spasmodic torticollis, truncal dystonia, writer’s cramp, and other occupational dystonias. Papers describing features of dystonia and diagnostic criteria are critically analyzed and put into historical perspective. Issues and inconsistencies in this lumping effort are discussed, and the currently unmet needs are critically reviewed.

Mental rotation and working memory in musicians’ dystonia

BackgroundMental rotation of body parts engages cortical-subcortical areas that are actually involved in the execution of a movement. Musicians’ dystonia is a type of focal hand dystonia that is grouped together with writer’s cramp under the rubric of “occupational dystonia”, but it is unclear to which extent these two disorders share common pathophysiological mechanisms. Previous research has demonstrated patients with writer’s cramp to have deficits in mental rotation of body parts. It is unknown whether patients with musicians’ dystonia would display similar deficits, reinforcing the concept of shared pathophysiology. MethodsEight patients with musicians’ dystonia and eight healthy musicians matched for age, gender and musical education, performed a number of tasks assessing mental rotation of body parts and objects as well as verbal and spatial working memories abilities. ResultsThere were no differences between patients and healthy musicians as to accuracy and reaction times in any of the tasks. ConclusionsPatients with musicians’ dystonia have intact abilities in mentally rotating body parts, suggesting that this disorder relies on a highly selective disruption of movement planning and execution that manifests only upon playing a specific instrument. We further demonstrated that mental rotation of body parts and objects engages, at least partially, different cognitive networks.

Focal dystonia in musicians: Phenomenology and musical triggering factors

Dystonias are defined as a joint sustained and involuntary contraction of agonist and antagonist muscles, which can cause torsion, repetitive abnormal involuntary movements, and/or abnormal postures. One special group of dystonias are those known as occupational, which include dystonia disorders triggered by a repetitive motor activity associated with a specific professional activity or task. Musicians are a population particularly vulnerable to these types of dystonia, which are presented as a loss of coordination and voluntary motor control movements highly trained in musical interpretation. Our aim is to describe a clinical series of focal dystonias in musicians evaluated and treated in our centre. Patients and methodsData are presented on a clinical series of 12 musicians with occupational dystonia. Their history and phenomenology are described, as well as well as their outcome after therapy. ResultsDemographic details: Mean age 34.8±11.8 years, 10 males (83.3%) and 2 females (16.7%). Clinical history: History of trauma in dystonic segment, 6 patients (50%); family history of neurological diseases in first-degree relatives, 6 patients (50%). Occupational history according to music category: 8 patients (66.6%) were classical musicians and 4 patients (33.3%) were popular musicians. PhenomenologyDystonia syndrome was characterised by having a mean age of onset of 28.2±11.3 years (range 18–57 years). The segment affected was the hand (91.7%) in 11 patients. Of all the musicians seen in the clinic, 9 of them (75%) received therapy. The majority of patients appeared to have triggering factors specific to musical execution and linked to the requirement of fine motor control. It should be mentioned that 50% of the musicians treated maintained their professional activity or position in the orchestra to which they belonged. ConclusionsThe majority of our phenomenological findings are consistent with those reported in the current literature. However, it is worth mentioning the presence of triggering factors attributed to the specific requirements of performing music, linked to the participation of fine motor control.

Some unusual sports-related neurologic conditions.

This article reviews some of the unusual sports-related neurologic disorders within the new and rapidly growing field of sports neurology that neurologists may encounter. Surfer's myelopathy is a potentially tragic disorder predominantly affecting novice surfers, leaving many who are affected by this condition with permanent paralysis. Neck-tongue syndrome is a rare primary headache disorder that can occur in athletes and nonathletes, and consists of paroxysmal neck and occipital pain and transient ipsilateral tongue numbness, triggered by sudden rotation of the neck. Athletes are also at risk for cervical arterial dissections, with golfers especially prone to vertebral rather than carotid dissections. Finally, "the yips" likely represents a form of occupational dystonia described in golfers. The syndromes described in this article range from relatively minor syndromes that cause discomfort or abnormal movement to potentially devastating cerebrovascular or myelopathic syndromes. Although the disorders described in this article are not common, they can affect individuals involved in sports at all levels, from the novice to the elite athlete, and may present to any neurologist. Neurologists should be aware of the potential for these syndromes to occur as a consequence of athletic activities in order to provide the most appropriate diagnosis, management, and counseling.

Distonía del músico: fenomenología y desencadenantes vinculados a la ejecución musical

Dystonias are defined as a joint sustained and involuntary contraction of agonist and antagonist muscles, which can cause torsion, repetitive abnormal involuntary movements, and/or abnormal postures. One special group of dystonias are those known as occupational, which include dystonia disorders triggered by a repetitive motor activity associated with a specific professional activity or task. Musicians are a population particularly vulnerable to these types of dystonia, which are presented as a loss of coordination and voluntary motor control movements highly trained in musical interpretation. Our aim is to describe a clinical series of focal dystonias in musicians evaluated and treated in our centre. Patients and methodsData is presented on a clinical series of 12 musicians with occupational dystonia. Their history and phenomenology are described, as well as well as their outcome after therapy. ResultsDemographic details: Mean age 34.8±11.8 years, 10 males (83.3%) and 2 females (16.7%). Clinical history: History of trauma in dystonic segment, 6 patients (50%); family history of neurological diseases in first-degree relatives, 6 patients (50%); occupational history according to music category, 8 patients (66.6%) were classical musicians and 4 patients (33.3%) were popular musicians. PhenomenologyThe dystonia syndrome was characterised by having a mean age of onset of 28.2±11.3 years (range 18-57 years). The segment affected was the hand (91.7%) in 11patients. Of all the musicians seen in the clinic, 9 of them (75%) received therapy. The majority of patients appeared to have triggering factors specific to musical execution and linked to the requirement of fine motor control. It should be mentioned that 50% of the musicians treated maintained their professional activity or position in the orchestra to which they belonged. ConclusionsThe majority of our phenomenological findings are consistent with those reported in the current literature. However, it is worth mentioning the presence of triggering factors attributed to the specific requirements of performing music, linked to the participation of fine motor control.

Teaching Video Neuro Images : Speech-induced oromandibular dystonia relieved by singing

We report a rare task-specific dystonia1,2 in a 26-year-old man with a 4-year progressive speech disorder characterized by oromandibular spasms. Family and medical history were unremarkable; he was never exposed to neuroleptic drugs or toxic agents. Neurologic examination revealed only speech-induced oromandibular dystonic movements, characterized by forced jaw opening, interfering with speech (video on the Neurology ® Web site at [www.neurology.org][1]). However, he was able to sing and to perform other voluntary activities (swallowing, drinking, chewing). Laboratory tests and brain magnetic resonance scans were normal. He received a placebo injection with no benefit. Trihexyphenidyl was started with moderate benefit. This rare form of dystonia is sometimes trig-gered by praying,1,2 resembling task-specific occupational dystonias. [1]: http://www.neurology.org

Role of Female Reproductive Hormones in Musicians' Dystonia

Musicians' dystonia is an occupational focal dystonia affecting men more often than women. We identified all patients presenting with musicians' dystonia and prospectively collected data on reproductive and menstrual history from the women with musician's dystonia and female musicians without dystonia. 149 men and 23 women (13.37%) with musician's dystonia where identified. We did not identify any effect of contraceptive hormones, pregnancy, or menstrual phases on dystonia symptoms, but as compared with women without dystonia, those with musician's dystonia reported oligomenorrhea and menometrorrhagia significantly less frequently. Our data reinforce the relation between sex hormones variations and musicians' dystonia. This link should be further explored to identify mechanisms and assess whether certain hormonal interventions might protect from the manifestation of dystonia.

Occupational Oromandibular Dystonia in an Opera Singer Mimicking Spasmodic Dysphonia

While occupational dystonia among singers is often described as laryngeal in nature, we describe a unique case of oromandibular (jaw closure/jaw deviation) dystonia in a professional opera singer occurring exclusively when attempting to sing in the higher registry. Occurring in the context of a high-risk profession, the patient’s tone-selective symptoms were mistaken for spasmodic dysphonia which obscured the correct diagnosis and resulted in delay of treatment. After establishing the diagnosis, significant improvement was noted with botulinum toxin injections to the mandibular muscles.

Occupational dystonia affecting truncal muscles in a bricklayer

Movement DisordersVolume 22, Issue 2 p. 284-285 Letter to the Editors Occupational dystonia affecting truncal muscles in a bricklayer William Baek MD, William Baek MD Department of Neurology, University of California San Diego, San Diego, CaliforniaSearch for more papers by this authorGeoffrey Sheean MBBS, FRACP, Geoffrey Sheean MBBS, FRACP Department of Neurology, University of California San Diego, San Diego, CaliforniaSearch for more papers by this author William Baek MD, William Baek MD Department of Neurology, University of California San Diego, San Diego, CaliforniaSearch for more papers by this authorGeoffrey Sheean MBBS, FRACP, Geoffrey Sheean MBBS, FRACP Department of Neurology, University of California San Diego, San Diego, CaliforniaSearch for more papers by this author First published: 06 November 2006 https://doi.org/10.1002/mds.21215Citations: 4Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume22, Issue215 January 2007Pages 284-285 RelatedInformation

Task-specific hand dystonia: can too much plasticity be bad for you?

Patients with occupational hand dystonias have task-specific involuntary co-contraction and overflow of activity to inappropriate muscles. This interferes with highly skilled movements such as handwriting (writer's cramp) or playing a musical instrument (musician's cramp). Transcranial stimulation methods that probe mechanisms of synaptic plasticity in the motor cortex show an abnormal modifiability of sensorimotor circuits in patients with writer's cramp, probably because homeostatic control of the range of modification is deficient. We argue that during skilled motor practice, this leads to an excessive tendency to form associations between sensory inputs and motor outputs (abnormal potentiation) and to a failure to weaken already existing associations (deficient depotentiation). Deficient homeostatic control might be an important mechanism that triggers maladaptive reorganization and produces symptoms of occupational hand dystonias.

Botulinum toxin treatment of occupational and focal hand dystonia.

Botulinum toxin is now the first-line therapy for writer's cramp and other occupational dystonias, with well-established efficacy and safety. Future studies will allow us to understand better the physiological effects of injection and to refine and enhance our treatment of focal hand dystonia.

Distonía del guitarrista: tratamiento con reeducación sensorial

Dystonia is defined as a sustained co-contraction of agonistic and antagonistic muscles that can cause twisting, twitching and abnormal postures. Occupational dystonias are included in a special group of pathologies that are secondary to a repeated effort related to the professional activity carried out by the sufferer, as can occur in guitarists, violinists and trumpet players, for example. Its pathophysiology includes descriptions of disorders affecting the peripheral and central nervous systems. Studies conducted in monkeys have shown that, through sensory stimulation, repeated movements can give rise to central anomalies in the somatosensory cortex, with growth of the receptive fields that are stimulated and deformation of the separations between those fields. We describe the case of a professional guitarist with a seven-year history of symptoms. A neurological examination revealed a co-contraction in the right hand that triggered the extension of the index and little fingers, which made it difficult for him to play his instrument. The patient was submitted to sensory re-education therapy with the use of a splint and a two-month routine of exercises. The response was evaluated using a subjective scale of the patient's symptoms and measurements of the maximum angles of flexion and extension of the affected fingers. Both methods reduced the patient's discomfort and allowed him to exhibit greater skill when playing the guitar. Occupational dystonias produced by repeated stimulation present alterations in the sensory region of the cortex, with the involvement of motor performance that improves with sensory re-education therapy.

Limb immobilization for the treatment of focal occupational dystonia

Limb immobilization for the treatment of focal occupational dystonia

Limb immobilization for the treatment of focal occupational dystonia.

Occupational focal upper-limb dystonia is characterized by involuntary muscle contractions that selectively interfere with the execution of specific motor tasks such as writing or playing a musical instrument. Occupational dystonias have a severe social impact, especially in certain professions. The available medical treatments offer little benefit. In eight patients with idiopathic occupational focal dystonia of the upper limb, the dystonic forearm and hand were immobilized with a plastic splint for mean (+/-SD) 4.5 +/- 0.75 weeks. Before splinting (base line) and at various intervals afterwards (4, 12, and 24 weeks), the authors assessed the severity of dystonia and the patients' motor performance objectively (Arm Dystonia Disability Scale and Tubiana and Chamagne Score) and subjectively (Self-Rating Score). Assessment 4 weeks after splint removal, when patients had regained normal voluntary movements, showed that the severity of dystonia and the patients' performance of the impaired motor task had improved; the benefit persisted unchanged at later follow-up visits (Arm Dystonia Disability Scale: base line 20.6 +/- 30.2%; after 4 weeks 83.9 +/- 23.8%, p = 0.007; after 12 weeks 83.9 +/- 23.8%, p = 0.007; after 24 weeks 79.7 +/- 29.5%, p = 0.015. Tubiana and Chamagne Score: base line 28.6 +/- 22.7%; after 4 weeks 80.0 +/- 23.1%, p = 0.015; after 12 weeks 80.0 +/- 23.1%, p = 0.015; after 24 weeks 74.3 +/- 32.1%, p = 0.031. Self-Rating Score: base line 20.6 +/- 19.3%; after 4 weeks 63.7 +/- 25.2%, p = 0.015; after 12 weeks 66.9 +/- 28.1%, p = 0.015; after 24 weeks 70.6 +/- 31.8%, p = 0.015). At the 24-week visit the improvement disappeared in one patient, was moderate in three, and marked in four. Limb immobilization can be a simple, effective, safe, and inexpensive treatment for focal occupational upper-limb dystonia.