Functional assessment and rehabilitative treatment in myotonic dystrophy type 1

Abstract

Motor impairment in Myotonic Dystrophy type 1 (DM1) involves different aspects of activity of daily living. Muscle weakness leads to impaired walking abilities, with an increased risk of stumbles and falls. While, motor performance can also be limited by the occurrence of precocious fatigability. Therefore the evaluation of functional impairment plays a central role in the chronic management of the disease. Muscle strength can be assessed by subjective clinical scale or by instrumental devices, such as isokinetic dynamometers, in order to limit the operator's test quality. Gait abilities can be assessed with standardized walking test, while computerized 3D gait analysis has been applied in order to quantitatively assess gait kinetics and kinematics. Moreover, instrumental assessment of balance impairment by means of posturography or stabilometric platforms is frequently used, generally accompanied by clinical balance scales. Exercise tolerance and resistance in general is assessed with cycle or treadmill submaximal incremental testing, while creatine kinase (CK) serum level are monitored in order to assess exercise safety. In this review, we will summarize the different rehabilitative approaches that have been proposed in these disease. Strength training and aerobic exercise programs have been proposed in order to improve impaired muscle and cardio-respiratory function and to prevent additional disuse atrophy The effects of aerobic training determines an improvement in terms of oxidative capacity and cardiovascular fitness. Moderateintense strength training seems harmless, even if there is still poor evidence of a real benefit. The effects of a specific resistance hand program was also evaluated, focusing on changes in hand function and in occupational performance. Only one trial evaluated the effects of a more comprehensive group exercise program, focusing on balance, strength and aerobic activities. An interesting approach tested the efficacy of a period of localized neuromuscular electrical stimulation on muscular weakness and the sarcolemmal excitability. In conclusion, patients with DM1 may probably benefit by strengthening exercises or aerobic protocols without any observed deleterious effect, even if the possible benefits in the long-term course are still not completely understood. Neuromuscular electrical stimulation could also be considered in the early management of the disease, as far as it represents a useful tool able to improve motor performance and walking abilities. Nevertheless, controlled trials performed on homogeneous groups and with wider number of patients should be tested. Moreover, specific both clinical and instrumental assessments need to be systematically introduced in everyday clinical practice, in order to evidence functional improvements