Dresel Christian, Haslinger Bernhard, Castrop Florian, Wohlschlaeger Afra M, Ceballos-Baumann Andrés O
Department of Neurology, Neurologisches Krankenhaus Muenchen, Germany.
Brain. 2006 Jan;129(Pt 1):36-46. doi: 10.1093/brain/awh665. Epub 2005 Nov 9.
Previous studies showed cortical dysfunction and impaired sensorimotor integration in primary generalized and focal hand dystonia. We used a whistling task and silent event-related fMRI to investigate functional changes in patients with blepharospasm and patients with a combination of blepharospasm and oromandibular dystonia (Meige's syndrome). Whistling served as a model for a skilful orofacial movement with a high demand on sensorimotor integration. It allowed us to study the oromandibular motor system that is clinically affected in Meige's syndrome but not in isolated blepharospasm. In Meige's syndrome, functional MRI revealed deficient activation of the primary motor and ventral premotor cortex within the mouth representation area during whistling. Compared with healthy controls, both forms of orofacial dystonia had increased activation of bilateral somatosensory areas and the caudal supplementary motor area (SMA) in common. While overactivity of somatosensory areas and caudal SMA in Meige patients was partly reversed by botulinum toxin treatment, impaired motor activation was not. We conclude that impaired motor activation appears to be specific for the clinically affected oromandibular motor system in Meige's syndrome while enhanced somatosensory activation is a common abnormality in both forms of orofacial dystonia independent of the affected motor system. Somatosensory overactivity indicates an altered somatosensory representation in orofacial dystonia while impaired motor activation may be a functional correlate of reduced cortical inhibition during oromandibular motor execution in Meige's syndrome.
先前的研究表明，原发性全身性和局灶性手部肌张力障碍存在皮质功能障碍以及感觉运动整合受损。我们使用吹口哨任务和静息事件相关功能磁共振成像（fMRI）来研究眼睑痉挛患者以及合并眼睑痉挛和口下颌肌张力障碍（梅杰综合征）患者的功能变化。吹口哨作为一种对感觉运动整合要求较高的熟练口面部运动模型。它使我们能够研究在梅杰综合征中临床上受影响但在孤立性眼睑痉挛中未受影响的口下颌运动系统。在梅杰综合征中，功能磁共振成像显示吹口哨时口腔代表区内初级运动皮层和腹侧运动前皮层激活不足。与健康对照相比，两种形式的口面部肌张力障碍均表现为双侧体感区和尾侧辅助运动区（SMA）激活增加。虽然肉毒杆菌毒素治疗部分逆转了梅杰综合征患者体感区和尾侧SMA的过度激活，但运动激活受损并未得到改善。我们得出结论，运动激活受损似乎是梅杰综合征中临床上受影响的口下颌运动系统所特有的，而体感激活增强是两种形式的口面部肌张力障碍的共同异常，与受影响的运动系统无关。体感过度激活表明口面部肌张力障碍中体感表征发生改变，而运动激活受损可能是梅杰综合征中口下颌运动执行过程中皮质抑制减弱的功能相关因素。
