Nijenhuis Beorn, Schalkwijk Aron H P, Hendriks Sharon, Zutt Rodi, Otten Egbert, Tijssen Marina A J
Department of Neurology University Medical Center Groningen, University Groningen Groningen the Netherlands.
Department of Neurology Haga Teaching Hospital the Hague the Netherlands.
Mov Disord Clin Pract. 2019 Aug 14;6(7):559-566. doi: 10.1002/mdc3.12799. eCollection 2019 Sep.
Skater's cramp is an involuntary lower leg movement in skilled speed skaters. We aim to evaluate whether skater's cramp is compatible with task-specific dystonia.
A case-control study tested 5 speed skaters exhibiting symptoms of skater's cramp and 5 controls. Affected skaters completed a standardized questionnaire and neurological examination. Video analyses included skating normally, intensely, and with extra mass around the skater's ankles. An Inertial Motion Capturing (IMC) device mounted on both skates provided angular velocity data for both feet.
Median time of onset of skater's cramp occurred after 12 (range 3-22) years of speed skating. Skater's cramp appeared as task specific; its onset was sudden and correlated to stress and aberrant proprioception. Symptoms presented acutely and consistently during skating, unilaterally in 4 and bilaterally in 1 skater. Visually, skater's cramp was an active, patterned, and person-specific jerking of a skater's foot, either exo- or endorotationally. It presented asymmetrically, repeating persistently as the foot neared the end of the swing phase. The skater's affected leg had a longer swing phase (median, 1.37 [interquartile range {IQR}, 0.35]/1.18 [IQR, 0.24] seconds; < 0.01), a shorter glide phase (median, 1.09 [IQR, 0.25]/1.26 (IQR, 0.29) seconds; < 0.01), and higher angular velocity during the jerking motion. Symptoms remained constant irrespective of speed or extra mass around the ankle ( > 0.05). No significant differences between legs were detected in the control group.
Observed clinical, visual, and kinematic data could be an early and tentative indication of task-specific dystonia.
滑冰者痉挛是熟练速滑运动员小腿的非自主运动。我们旨在评估滑冰者痉挛是否与任务特异性肌张力障碍相符。
一项病例对照研究对5名有滑冰者痉挛症状的速滑运动员和5名对照者进行了测试。受影响的速滑运动员完成了一份标准化问卷和神经学检查。视频分析包括正常滑冰、高强度滑冰以及在滑冰者脚踝周围增加额外重量的情况下滑冰。安装在两只冰鞋上的惯性运动捕捉（IMC）设备提供了双脚的角速度数据。
滑冰者痉挛的中位发病时间出现在速滑12年（范围3 - 22年）之后。滑冰者痉挛表现为任务特异性；其发作突然，与压力和异常本体感觉相关。症状在滑冰时急性且持续出现，4名滑冰者为单侧，1名滑冰者为双侧。从视觉上看，滑冰者痉挛是滑冰者脚部主动、有规律且因人而异的外旋或内旋抽搐。它不对称出现，在脚部接近摆动阶段末尾时持续重复。受影响滑冰者的腿部摆动阶段更长（中位值，1.37 [四分位间距{IQR}，0.35]/1.18 [IQR，0.24]秒；<0.01），滑行阶段更短（中位值，1.09 [IQR，0.25]/1.26（IQR，0.29）秒；<0.01），且在抽搐运动期间角速度更高。无论速度或脚踝周围的额外重量如何，症状均保持不变（>0.05）。对照组两腿之间未检测到显著差异。
观察到的临床、视觉和运动学数据可能是任务特异性肌张力障碍的早期初步迹象。
