Safety of transcranial direct current stimulation in a patient with deep brain stimulation electrodes / Segurança da estimulação transcraniana por corrente contínua em uma paciente com implante de eletrodos de estimulação cerebral profunda

ABSTRACT Background: Transcranial direct current stimulation (tDCS) has been investigated in movement disorders, making it a therapeutic alternative in clinical settings. However, there is still no consensus on the most appropriate treatment protocols in most cases, and the presence of deep brain stimulation (DBS) electrodes has been regarded as a contraindication to the procedure. We recently studied the effects of cerebellar tDCS on a female patient already undergoing subthalamic nucleus deep brain stimulation (STN-DBS) for generalized dystonia. She also presented with chronic pain and depression. With STN-DBS, there was improvement of dystonia, and botulinum toxin significantly reduced pain. However, depressive symptoms were worse after STN-DBS surgery. Methods: Neuromodulation with 2 mA anodal cerebellar tDCS was initiated, targeting both hemispheres in each daily 30 minute session: 15 minutes of left cerebellar stimulation followed by 15 minutes of right cerebellar stimulation. The DBS electrodes were in place and functional, but the current was turned off during tDCS. Results: Although our goal was to improve dystonic movements, after 10 tDCS sessions there was also improvement in mood with normalization of Beck Depression Inventory scores. There were no complications in spite of the implanted STN-DBS leads. Conclusion: Our results indicate that tDCS is safe in patients with DBS electrodes and may be an effective add-on neuromodulatory tool in the treatment of potential DBS partial efficacy in patients with movement disorders.

RESUMO Descrição: A estimulação transcraniana por corrente contínua (ETCC) tem sido investigada nos distúrbios de movimento, tornando-a uma alternativa terapêutica no contexto clínico. Contudo, não há consenso quanto aos protocolos mais apropriados na maioria dos casos e a presença de eletrodos de estimulação cerebral profunda (ECP) é geralmente considerada uma contraindicação. Recentemente, estudamos os efeitos da ETCC cerebelar em uma paciente do sexo feminino com implante de eletrodos de estimulação cerebral profunda (ECP) para distonia generalizada. Ela também apresentava dor crônica e depressão. A ETCC foi realizada dois anos após o implante de eletrodos de ECP. Com a ECP houve melhora da distonia e a toxina botulínica reduziu a dor. Contudo, os sintomas depressivos pioraram após a cirurgia de ECP. Métodos: Foi proposta ETCC cerebelar anódica de 2mA, sobre os dois hemisférios em cada sessão de 30min: 15 min de ETCC cerebelar esquerda seguida de 15min de ETCC cerebelar direita. Resultados: Embora o nosso objetivo tenha sido melhorar os movimentos distônicos, após 10 sessões de ETCC houve melhora também do humor da paciente. Não houve nenhuma complicação, apesar da presença de eletrodos de ECP. Conclusão: Nossos resultados apontam para a segurança da tDCS e sua aplicação potencial e efetiva como ferramenta neuromodulatória adicional no tratamento de possíveis sintomas persistentes após a ECP em pacientes com distúrbios de movimento.

Distonía focal en músicos / FOCAL DYSTONIA IN MUSICIANS

The aim of this report was to describe the Focal dystonia in Musicians. Musician´s dystonia is a disorder characterized by abnormal movements, with excessive activation of muscular antagonists or co-contraction of antagonist muscles that are not required for a specific movement. Belongs to the group of occupational dystonias ; is a specific disorder of a determinated task in musicians, that include the absence of voluntary control of movements detailed determinated in the ejecution of an instrument, and manifiests itself by the deteriorization of his dexterity in the ejecution. Dystonia, including all his forms, is the third more frequent pathology of abnormal movements, after Parkinson´s disease and the essential trembling. Musician´s dystonia is a task-specific movement that manifiests itself as a loss of voluntary motor control in extensively trained movements. Approximately 1 % of all professional musicians develop musician´s dystrofia, and in many cases the disorder terminates the careers of affected musicians. Several theories have been referred related to the etiology. The aim of this report was to present the author´s casuistic of Focal dystonia in musicians in Argentina, considering the type of instrument, which kind of music is ejecuted ­classic or popular- and to inform the treatment proposed and the results obtained.

Combinación de tres técnicas en el reentrenamiento de un músico con distonía focal: estudio de un caso / The use of three combined techniques in the retraining of a mucisian with focal dystonia: a case study

La distonía resulta de una co-contracción sostenida de músculos agonistas y antagonistas que puede causar torsión, movimientos involuntarios o posturas anormales que interfieren con el control voluntario de la mano, u otro grupo muscular, involucrados en una determinada acción; por ejemplo, tocar un instrumento, o escribir.El presente estudio descriptivo, de caso único, buscó probar la efectividad de un tratamiento que combinó tres técnicas (técnica del umbral, imaginería, y relajación por neurofeedback) en el reentrenamiento de un concertista profesional con distonía focal. Según evaluación por jueces, los resultados después de dos semanas de tratamiento, no fueron concluyentes. Sin embargo, el reporte experiencial del propio músico dio cuenta de una clara mejoría. Ante la carencia de un método efectivo para larehabilitación demúsicos con distonía focal, la relevancia del presente estudio consistió en identificar y combinar técnicas específicas que pueden contribuir a ese propósito. En estudios futuros, sería de interés probar el efecto del mismo tratamiento,pero más prolongado; o el efecto de la incorporación de las técnicas en sucesión progresiva, iniciando siempre con la relajación por neurofeedback.

Focal dystonia results from a sustained simultaneous co-contraction of agonists and antagonists muscle fibers which can cause twisting, involuntary movements or abnormal postures that interfere with voluntary control of the hand, arm, mouth, or other muscle groups involved in a given action; for example, playing an instrument, or hand writing. This descriptive, single case study, sought to explore the effectiveness of a treatment that combined three procedures: the threshold technique, imagery, and neurofeedback induced relaxation, in retraining of a professional cello player with focal dystonia. After two weeks of treatment, experts judged the results inconclusive; however, the report from the actual patient accounted for a note worthy recovery over time. In the absence of an effective method to rehabilitate musicians with focal dystonia, the relevance of this study resided on thepossibility of identifying and combining specific techniques that could be effective. Future studies might want to explore these same or different techniques, but perhaps for a longer period of time.