Active clinical trials for "Myotonia"

In myotonia congenita (MC), mutations in the CLCN1 gene coding a key chloride channel expressed in muscle cells cause myotonia. On examination, the myotonia can be demonstrated as delayed muscle relaxation of muscle contractions after mechanical stimulations. Existing literature describe no muscle weakness in MC patients, however a recent muscle MRI study in non-dystrophic myotonia patients found structural abnormalities in affected muscles when examined using T1 and STIR imaging. The question remains whether the signs of structural changes in the muscle are merely due to the myotonia, or long-term effects of elevated stress of the tissue, and if so, whether those changes lead to clinically significant loss of contractile properties of the muscle. This study examines if the contractile properties of myotonic muscles are impaired in MC patients. 40 patients with Thomsens disease (n=20) and Beckers disease (n=20), respectively, will be included along with 20 healthy controls. Peak muscle torque is measured in the hand by hand dynamometer and in the thigh and calf muscles with a Biodex System 4 Pro Dynamometer and the cross-sectional area of the muscles are examined on T1-weighed and Dixon-MRI-scan. With the obtained data peak torque in strength tests, muscle hypertrophy, fat fraction in muscle tissue and contractility of the muscles, compared with healthy controls, will be assessed.

Background: Myotonic dystrophy lead to highly heterogeneous, multisystemic symptoms including myotonia, progressive muscle weakness, cardiac conduction defects, cataract, metabolic dysfunction, and excessive daytime somnolence. This last symptom is related to respiratory failure and/or to involvement of the central nervous system. However the metabolic disturbances could contribute to it. From the respiratory point of view this disease is characterised by the progressive appearance of respiratory failure of muscular origin but mainly associated with a defect in the central respiratory drive. The treatment for this hypoventilation is non-invasive ventilation (NIV). It is not currently absolutely clear as to the best choice of criteria to judge long term effectiveness of NIV. The most usual criteria are normalisation of daytime blood gases, diminution of respiratory work, improvement in daytime symptoms and improvement in sleep structure. Other criteria are currently little studied, for instance the contribution of the interaction between alveolar hypoventilation and oxygen desaturation during the night and biological deficiencies such as systemic inflammation, glucose intolerance or insulin resistance. Likewise there is little information about the interaction between alveolar hypoventilation and endothelial dysfunction and arterial stiffness both being accurate predictive factors for cardiovascular risks. Aim: to evaluate the impact of NIV on endothelial dysfunction in patients with myotonic dystrophy. The secondary objectives are to assess the impact of NIV on systemic inflammation, arterial stiffness, insulin-resistance, quality of sleep, and daytime vigilance in these patients. Methods: Patients with chronic alveolar hypoventilation already treated by long term NIV will be included. They will have an initial check-up (Visit 1), then will interrupt NIV treatment for four weeks (Visit 2), and then return to NIV treatment. The last check-up will be done four weeks after NIV resumption (Visit3). Expected results: It is expected that NIV withdrawal will results in a deterioration of cardio-vascular parameters (endothelial function and arterial stiffness), metabolic parameters (insulin-resistance and systemic inflammation), quality of sleep and daytime vigilance. Return to NIV treatment may show an improvement of these parameters with a basal state recovery.

Nondystrophic myotonias (NDM) are muscle disorders caused by genetic abnormalities in certain muscle cell membrane proteins. Individuals with NDM experience limited muscle relaxation, which causes pain, weakness, and impaired physical activity. The purpose of this study is to better characterize the clinical features and symptoms of NDM.

The primary objective of this study is to assess stiffness, muscle tone, relaxation periods and elasticity of various muscles in patients with dystrophic or non-dystrophic myotonia. The secondary objectives are (1) to provide reference values for stiffness, muscle tone, relaxation periods and elasticity of various muscles in patients with dystrophic or non-dystrophic myotonia; to provide reference values for stiffness, muscle tone, relaxation periods and elasticity of various muscles in patients with non-myotonic neuromuscular disorders, (3) assess correlations between to compare result values for stiffness, muscle tone, relaxation periods and elasticity with clinical muscle function tests, measured by clinical evaluation (MRC-scale) and the 6-minute walk test; (4) assess correlations between subcutaneous fat and muscle thickness and echogenicity, measured by muscle ultrasound and result values for stiffness, muscle tone, relaxation periods and elasticity.

The aim of this project is (1) to investigate whether or not structural muscle abnormalities could be a consequence of the disorder and (2) to provide further clinical description of this rare phenotype. To do so, the investigators will (1) use Dixon MRI to quantify fatty infiltration in muscle tissue and compare it to muscle strength measurements from isometric dynamometry in order to access contractility and (2) describe the myotonic phenotype with simple squeeze test and questionnaires.