To quantitate improvement in hand- grip myotonia and muscle strength (i.e., the “ warm- up” phenomenon) in myotonic dystrophy type 1 (DM1), six successi ve, standardized maximum voluntary isometric contractions (MVI...To quantitate improvement in hand- grip myotonia and muscle strength (i.e., the “ warm- up” phenomenon) in myotonic dystrophy type 1 (DM1), six successi ve, standardized maximum voluntary isometric contractions (MVICs) were recorded on 2 separate days using a computerized isometric hand- grip myometer in 25 gen etically confirmed DM1 patients and in 17 normal controls. An automated computer program placed cursors along the declining (relaxation) phase of the MVICs at 9 0% , 50% , and 5% of peak force (PF) and calculated relaxation times (RTs) b etween these points. Mean 90% to 5% RT (a measure of myotonia) rapidly decli ned from 2.5 s in MVIC 1 to 0.8 s in MVIC 6 (warm- up=1.7 s) in DM1; in control s, it remained 0.4 s for all six MVICs (warm- up=0). In DM1, 70% of warm- up occurred between MVIC 1 and 2, almost exclusively in the terminal 50% to 5% phase of muscle relax ation. Day 1 warm- up was highly correlated with the severity of myotonia, and with day 2 warm- up. Improvement in myotonia was not accompanied by either tran sient paresis or improvement in PF.We conclude that, with this testing paradigm: warm- up of myotonia in DM1 can be reliably measured; is proportional to sever ity of myotonia; occurs rapidly, being most prominent between the first and seco nd grips; mainly results from shortening of the terminal phase of muscle relaxat ion; and is not accompanied by significant warm- up in force output.展开更多
帕金森病(Parkinson’s disease,PD)是以黑质致密部(substantia nigra pars compacta,SNpc)多巴胺能神经元的丢失和α-突触核蛋白(alpha-synuclein,α-Syn)的异常聚集为主要特征的神经退行性疾病[1]。PD的症状可分为运动性和非运动性两...帕金森病(Parkinson’s disease,PD)是以黑质致密部(substantia nigra pars compacta,SNpc)多巴胺能神经元的丢失和α-突触核蛋白(alpha-synuclein,α-Syn)的异常聚集为主要特征的神经退行性疾病[1]。PD的症状可分为运动性和非运动性两类,运动性症状包括运动迟缓、肌肉强直、静止性震颤、姿势和步态障碍,非运动性症状包括嗅觉障碍、认知障碍、精神症状、睡眠障碍、自主神经功能障碍、疼痛和疲劳[2-3]。展开更多
文摘To quantitate improvement in hand- grip myotonia and muscle strength (i.e., the “ warm- up” phenomenon) in myotonic dystrophy type 1 (DM1), six successi ve, standardized maximum voluntary isometric contractions (MVICs) were recorded on 2 separate days using a computerized isometric hand- grip myometer in 25 gen etically confirmed DM1 patients and in 17 normal controls. An automated computer program placed cursors along the declining (relaxation) phase of the MVICs at 9 0% , 50% , and 5% of peak force (PF) and calculated relaxation times (RTs) b etween these points. Mean 90% to 5% RT (a measure of myotonia) rapidly decli ned from 2.5 s in MVIC 1 to 0.8 s in MVIC 6 (warm- up=1.7 s) in DM1; in control s, it remained 0.4 s for all six MVICs (warm- up=0). In DM1, 70% of warm- up occurred between MVIC 1 and 2, almost exclusively in the terminal 50% to 5% phase of muscle relax ation. Day 1 warm- up was highly correlated with the severity of myotonia, and with day 2 warm- up. Improvement in myotonia was not accompanied by either tran sient paresis or improvement in PF.We conclude that, with this testing paradigm: warm- up of myotonia in DM1 can be reliably measured; is proportional to sever ity of myotonia; occurs rapidly, being most prominent between the first and seco nd grips; mainly results from shortening of the terminal phase of muscle relaxat ion; and is not accompanied by significant warm- up in force output.
文摘帕金森病(Parkinson’s disease,PD)是以黑质致密部(substantia nigra pars compacta,SNpc)多巴胺能神经元的丢失和α-突触核蛋白(alpha-synuclein,α-Syn)的异常聚集为主要特征的神经退行性疾病[1]。PD的症状可分为运动性和非运动性两类,运动性症状包括运动迟缓、肌肉强直、静止性震颤、姿势和步态障碍,非运动性症状包括嗅觉障碍、认知障碍、精神症状、睡眠障碍、自主神经功能障碍、疼痛和疲劳[2-3]。
