What can kinematic studies tell us about the mechanisms of dystonia?

Clinical movement disorders are classified by an algorithm implemented by a practising movement disorder specialist based on information extracted during the history and clinical examination of a patient. Most simply, dystonia, is a classifier which is reached when a predominant abnormality of posture is noted. In this chapter we summarize studies that have used a variety of techniques to probe beyond the clinical examination and study kinematic features experimentally. We also outline our experimental work in DYT1 dystonia, a group of patients that share a genetically homogenous etiology and can be considered a prototypical dystonic disorder. Our results build on previous studies, confirming that motor variability on a trial-by-trial basis is selectively increased and provide evidence that increases in variability are negatively related to forms of motor learning essential for healthy motor control. Potential neural correlates of increased motor variability are discussed and the implications such work has for the rehabilitation of patients with dystonia are also highlighted.

Distonía del músico: fenomenología y desencadenantes vinculados a la ejecución musical / Focal dystonia in musicians: Phenomenology and musical triggering factors

Las distonías se definen como una contracción conjunta, sostenida e involuntaria de músculos agonistas y antagonistas, que puede causar torsión, movimientos involuntarios anormales repetitivos y/o posturas anormales. Un grupo especial de distonías son las conocidas como ocupacionales, que incluyen trastornos distónicos desencadenados por una actividad motora repetitiva, relacionada con la actividad profesional o tarea específica. Los músicos son una población especialmente vulnerable a este tipo de distonías que se presentan como una pérdida de coordinación y control motor voluntario de movimientos altamente entrenados en la interpretación musical. Nuestro objetivo es describir una serie clínica de distonías focales en músicos evaluados y tratados en nuestro centro. Pacientes y métodos: Se presentan los datos de una serie clínica de 12 músicos con distonía ocupacional; se describen sus antecedentes y fenomenología, así como su evolución después de de la terapia. Resultados: Antecedentes demográficos: edad promedio 34,8 ± 11,8 años, 10 hombres (83,3%) y 2 mujeres (16,7%). Antecedentes médicos: antecedentes traumáticos en segmento distónico, 6 pacientes (50%); antecedentes familiares de enfermedades neurológicas en parientes de primer grado, 6 pacientes (50%); antecedentes laborales según categoría musical, 8 pacientes (66,6%) eran músicos clásicos y 4 pacientes (33,3%) eran músicos populares. Fenomenología: El cuadro distónico se caracterizó por presentarse a una edad promedio de inicio de 28,2 ± 11,3 años (rango 18-57 años). En 11 pacientes el segmento afectado fue la mano (91,7%). De todos los músicos consultados, un total de 9 (75%) recibió terapia. En la mayoría de los pacientes se describen desencadenantes específicos de la ejecución musical, asociados a requerimientos de control motor fino. Cabe mencionar que el 50% de los músicos tratados mantuvo su actividad laboral o puesto en la orquesta a la que pertenecía. Conclusiones: La mayoría de nuestros hallazgos fenomenológicos son coherentes con la literatura actualmente disponible. Sin embargo, nos parece destacable la presencia de desencadenantes atribuibles a requerimientos específicos de la ejecución musical, ligados a la participación del control motor fino

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 methods: Data 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. Results: Demographic 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. Phenomenology: The 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. Conclusions: The 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

Factitious torsion dystonia in rehabilitation: a singular new case and literature review.

We report a case of a 29-year-old woman suffering from chronic factitious disorder (FD) with torsion dystonia. For nearly five years, she traveled widely over the country, going from one hospital to another, taking serious medical risk in order to prolong her illness. After several admissions to Rehabilitation Units and multiple explorations, we find convincing evidence for factitious origin and the diagnosis of Munchausen syndrome was evoked. Such a clinical presentation is infrequent in Munchausen's syndrome. Indeed, most often the clinical picture is characterized by acute abdominal pain, fainting, hemoptysis, precordialgia, hematemesis or dermatological lesions. Physicians should be aware of this rare and potentially critical form of FD. Awareness in identifying these patients may lead to prevent unnecessary medical and/or surgical interventions.

A novel quality of life instrument for deep brain stimulation in movement disorders.

OBJECTIVE: To develop a short instrument to examine quality of life (QoL) which specifically addresses patients with movement disorders treated by deep brain stimulation (DBS). DESIGN: The instrument was developed within an existing concept of a modular questionnaire (questions on life satisfaction: "general life satisfaction" QLS(M)-A, and "satisfaction with health" QLS(M)-G), in which each item is weighted according to its relative importance to the individual. METHODS: Items were generated by interviews with 20 DBS patients, followed by item reduction and scale generation, factor analysis to determine relevant and final questionnaire items, estimation of reliability, and validation based on the medical outcome study 36 item short form health survey (SF-36) and the EuroQol (EQ-5D) (data from 152 patients with Parkinson's disease, essential tremor, or idiopathic torsion dystonia, including 75 patients with DBS). RESULTS: Initial questionnaires were reduced to 12 items for a "movement disorder module" (QLS(M)-MD), and five items for a "deep brain stimulation module" (QLS(M)-DBS). Psychometric analysis revealed Cronbach's alpha values of of 0.87 and 0.73, and satisfactory correlation coefficients for convergent validity with SF-36 and EQ-5D. CONCLUSIONS: QLS(M)-MD and QLS(M)-DBS can evaluate quality of life aspects of DBS in movement disorders. Psychometric evaluation showed the questionnaires to be reliable, valid, and well accepted by the patients.

Functional recovery after bilateral pallidotomy for the treatment of early-onset primary generalized dystonia.

This report describes the successful treatment of dystonia musculorum deformans with bilateral stereotactic pallidotomy in a 14-year-old girl in whom the dystonia was diagnosed when she was 7 years old. The patient presented with dystonia of the right upper extremity that progressed to generalized dystonia. Preoperatively, she required maximal assistance with all activities of daily living and transfers. She was not a functional ambulator. Postoperatively, she had remarkable functional recovery. At discharge, she was at modified independence level for all basic activities of daily living and required supervision for household ambulation. No postoperative complications were noted. We propose that bilateral stereotactic lysis of globus pallidus interna may be an alternative treatment for dystonia musculorum deformans. The technique of bilateral pallidotomy and theories of its effectiveness are discussed.

Distonía Muscular Deformante / Dystonia Musculorum Deformans

La Distonía Muscular Deformante (DMD) se caracteriza por la presencia de contracciones musculares involuntarias que alteran la postura y el movimiento voluntario, el cuadro clínico tiene un curso progresivo y se presenta en niños o personas genéticamente predispuestas. Es importante la diferenciación de la DMD de otras entidades como la enfermedad de Wilson, secuelas de la encefalopatía perinatal, enfermedades metabólicas, enfermedad de Hallevorden-Spatz, entre otras. Las distonías se pueden clasificar en primarias o idiopáticas y secundarias o sintomáticas; en las primarias el daño es de tipo funcional y en las secundarias se encuentran anormalidades en las neuroimágenes y alteraciones anatomopatológicas en los ganglios de la base. El inicio de los síntomas está entre los 5 y los 15 años de edad. La DMD se puede presentar como trastornos en la marcha, dificultad en el uso de una o ambas extremidades superiores y movimientos o posturas anormales del cuello o tronco. En el diagnóstico es muy importante tener en cuenta la diferenciación de algunas formas de parálisis cerebral y la evidencia de signos clínicos como la disartria, movimientos faciales y linguales anormales, disfagia y temblores de postura. Como terapia se puede recurrir a la L-dopa especialmente en las formas de fluctuación diurna. El empleo de carbamazepina, fenitoína, diazepam y haloperidol ha dado resultados inciertos y dispares. El uso de artane en pediatría permite obtener una respuesta temprana sin poder establecer la dosis correspondiente. Se debe insistir en el manejo de la terapia física para evitar los dolores y deformaciones

Dystonia musculorum deformans: three cases treated on a rehabilitation unit.

Dystonia musculorum deformans is a rare involuntary movement disorder of unknown etiology. We treated three brothers in one family on our rehabilitation unit, resulting in definite improvement in their ability to walk and control the dystonic movements, and in their speech and swallowing. All three benefited from orthoses to prevent equinovarus and maintain ankle stability. Intense concentration, such as needlepoint, seemed to reduce the amount of extra motion. Performing another activity during dystonic movements, such as pointing to a communication board, also seemed to give some relief. A special seating system using a collapsible wheelchair, a low center of gravity, and antitip wheels reduced one brother's frequency of falling. Swallowing finely cut foods was not a problem with any of our patients, although one had to be instructed in a special technique. An electronic communication board was very helpful. Our success in these cases should encourage others working in rehabilitation to consider such patients and to apply the principles of rehabilitation, particularly the total team approach, in their care.

Rehabilitation of communication impairment in dystonia musculorum deformans.

Augmentative and alternative communication (AAC) aids were used in three young, intellectually normal patients with dystonia musculorum deformans (DMD) who had severe speech and writing impediments. These aids included speech therapy, communication boards, and voice synthesizers for verbal communication and typewriters, memowriters, and computer software and printers for written communication. At times customized accessing was needed which required specific adaptive modifications. Implementation of the AAC aids system was determined effective for DMD patients in view of the intellect-sparing nature of the disorder. Improvement was hampered by the progressive nature of the disease and by the emotional stress of accepting the long-term use of AAC. Correct and early diagnosis of communication impediments are crucial for the appropriate AAC aids prescription and implementation. An AAC protocol is suggested to meet the special communication needs of DMD patients.

[Dystonia musculorum deformans. Elements of a favorable development]. / Dystonie musculaire déformante. Eléments d'une évolution favorable.

The therapeutic benefits of a concomitant approach to the disease and to the patient's identity experienced by the authors is illustrated by this case of a child presenting with dystonia musculorum deformans and severe disturbances of identity. This work was part of a research program concerning the function of these approaches and the operative modalities of their combinations.

EMG feedback therapy: review of treatment of 114 patients.

Advances in the understanding of the relationship of proprioceptive (kinesthetic) feedback to motor physiology have prompted the study of therapeutic effects of audiovisual displays of EMG activity. Patients with various manifestations of disturbed neuromotor control were studied prospectively for three years. This group included 114 patients with hemiparesis, torticollis, dystonia, and spinal cord or peripheral nerve injury. Initially, all but one of these patients had some residual volitional motor activity, which was insufficient for adequate function, and all patients had had conventional therapy with little or no functional recovery. Prior to EMG feedback therapy, the duration of illness was from three months to 35 years. The shaping of a patient's motor responses usually occurred gradually, often over an 8 to 12 week period. This modification was accomplished by feeding processed audio-visual signals back to the patient. These signals were proportional to the degree of activity of the muscles responsible for the defective function. The concept of microvolt-second, as a unit of muscle activity, is introduced and defined. Patterned movements, which were previously defective were observed to improve to varying degrees. Following the initial course of treatment, reinforcement was required by some patients. The mechanisms of improvement after EMG feeback therapy are not well understood; however, some hypotheses are presented. The results of this study indicate that EMG feedback therapy may induce significant functional recovery in patients with disturbed neuromotor control.