Orth Michael, Münchau Alexander, Rothwell John C
Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, United Kingdom.
Biol Psychiatry. 2008 Aug 1;64(3):248-51. doi: 10.1016/j.biopsych.2007.12.009. Epub 2008 Feb 4.
Several measures of motor cortex excitability are abnormal in Gilles de la Tourette syndrome (GTS). However, it is not clear whether these represent abnormalities of specific pathways or reflect a more widespread reduction of motor cortex excitability. Their significance for the clinical phenotype is also unknown.
We measured motor thresholds, input-output (I/O) curves, short interval intracortical inhibition (SICI), and cortical silent period (SP) with transcranial magnetic stimulation in 20 untreated GTS patients (12 uncomplicated, 4 with comorbid attention-deficit/hyperactivity disorder, 4 with comorbid obsessive-compulsive disorder) and 24 healthy subjects. Tics were rated with standard clinical scales and detailed video analysis.
Thresholds did not differ between groups. At rest, patients had shallower I/O curve slopes, despite their tics, and reduced SICI. Slopes were equal during voluntary muscle activation, as was the SP duration. Resting I/O slopes correlated, in uncomplicated GTS patients, most strongly to ratings of complex tics, hand and finger tics, and vocal tics, with shallower slopes predicting fewer tics. In complicated patients, good correlations were seen with neck/shoulder tics and vocal tics.
Corticospinal excitability in patients at rest is reduced. We suggest this is an adaptive response that may reduce release of unwanted movements.
在抽动秽语综合征（GTS）中，运动皮层兴奋性的几种测量指标异常。然而，尚不清楚这些异常是代表特定通路的异常，还是反映了运动皮层兴奋性更广泛的降低。它们对临床表型的意义也尚不清楚。
我们用经颅磁刺激测量了20例未经治疗的GTS患者（12例无并发症，4例合并注意缺陷多动障碍，4例合并强迫症）和24名健康受试者的运动阈值、输入-输出（I/O）曲线、短间隔皮质内抑制（SICI）和皮质静息期（SP）。用标准临床量表和详细的视频分析对抽动进行评分。
两组之间的阈值没有差异。在静息状态下，尽管患者有抽动，但I/O曲线斜率较浅，SICI降低。在自主肌肉激活期间，斜率相等，SP持续时间也相等。在无并发症的GTS患者中，静息I/O斜率与复杂抽动、手部和手指抽动以及发声抽动的评分相关性最强，斜率越浅，抽动越少。在复杂患者中，与颈部/肩部抽动和发声抽动有良好的相关性。
静息状态下患者的皮质脊髓兴奋性降低。我们认为这是一种适应性反应，可能会减少不必要运动的释放。
