Scarano Stefano, Sansone Valeria Ada, Ferrari Aggradi Carola Rita, Carraro Elena, Tesio Luigi, Amadei Maurizio, Rota Viviana, Zanolini Alice, Caronni Antonio
Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.
Department of Neurorehabilitation Sciences, IRCCS Istituto Auxologico Italiano, Ospedale San Luca, Milan, Italy.
Front Hum Neurosci. 2022 Jul 28;16:925299. doi: 10.3389/fnhum.2022.925299. eCollection 2022.
Falls are frequent in Myotonic Dystrophy type 1 (DM1), but the pathophysiology of the balance impairment needs further exploration in this disease. The current work aims to provide a richer understanding of DM1 imbalance. Standing balance in 16 patients and 40 controls was tested in two posturographic tests (EquiTest™). In the Sensory Organization Test (SOT), standstill balance was challenged by combining visual (eyes open vs. closed) and environmental conditions (fixed vs. sway-tuned platform and/or visual surround). In the "react" test, reflexes induced by sudden shifts in the support base were studied. Oscillations of the body centre of mass (COM) were measured. In the SOT, COM sway was larger in patients than controls in any condition, including firm support with eyes open (quiet standing). On sway-tuned support, COM oscillations when standing with closed eyes were larger in patients than controls even after taking into account the oscillations with eyes open. In the "react" paradigm, balance reflexes were delayed in patients. Results in both experimental paradigms (i.e., SOT and react test) are consistent with leg muscle weakness. This, however, is not a sufficient explanation. The SOT test highlighted that patients rely on vision more than controls to maintain static balance. Consistently enough, evidence is provided that an impairment of proprioceptive and vestibular systems contributes to falls in DM1. Rehabilitation programs targeted at reweighting sensory systems may be designed to improve safe mobility in DM1.
1型强直性肌营养不良（DM1）患者经常跌倒，但这种疾病平衡功能受损的病理生理学仍需进一步探索。当前的研究旨在更深入地了解DM1患者的平衡功能失调情况。对16例患者和40名对照者进行了两项姿势描记测试（EquiTest™）以检测站立平衡。在感觉组织测试（SOT）中，通过结合视觉（睁眼与闭眼）和环境条件（固定平台与摆动调节平台和/或视觉环绕）来挑战静立平衡。在“反应”测试中，研究了支撑基础突然移动所诱发的反射。测量了身体重心（COM）的摆动情况。在SOT中，在任何条件下，包括睁眼时的稳定支撑（安静站立），患者的COM摆动都比对照者大。在摆动调节支撑上，即使考虑到睁眼时的摆动情况后，患者闭眼站立时的COM摆动仍比对照者大。在“反应”范式中，患者的平衡反射延迟。两种实验范式（即SOT和反应测试）的结果均与腿部肌肉无力相符。然而，这并不是一个充分的解释。SOT测试凸显出患者比对照者更依赖视觉来维持静态平衡。同样地，有证据表明本体感觉和前庭系统受损是导致DM1患者跌倒的原因之一。针对重新调整感觉系统权重的康复计划或许可以设计出来以改善DM1患者的安全移动能力。
