Toth A, Lovadi E, Komoly S, Schwarcz A, Orsi G, Perlaki G, Bogner P, Sebok A, Kovacs N, Pal E, Janszky J
Department of Neurology, University of Pécs, Pécs, Hungary.
Department of Neurosurgery, University of Pécs, Pécs, Hungary.
Acta Neurol Scand. 2015 Jul;132(1):65-72. doi: 10.1111/ane.12360. Epub 2015 Jan 28.
Myotonic dystrophy type 1 (DM1) is a common adulthood muscular dystrophy, characterized by muscle wasting, myotonia, and multisystemic manifestations. The phenomenon of involuntary muscle contraction during myotonia offers a unique possibility of investigating brain motor functions. This study explores cortical involvement during grip myotonia in DM1.
Sixteen DM1 patients were enrolled in the study. Eight patients had apparent grip myotonia, while eight patients did not (control subjects). All patients underwent functional MRI grip task examination twice: prior a warm-up procedure (myotonia was elicited in patients with apparent grip myotonia) and after a warm-up procedure (myotonia was attenuated in patients with apparent grip myotonia). No myotonia was elicited during either examination in patients without apparent grip myotonia. Cerebral blood oxygen level-dependent (BOLD) signals were compared both between groups with and without apparent myotonia, and between pre- and post-warm-up sessions.
Significantly higher BOLD signal was found during myotonia phase in patients with apparent grip myotonia compared to corresponding non-myotonia phase of patients without apparent grip myotonia in the supplementary motor area and in the dorsal anterior cingulate cortex. Significant differences in BOLD signal levels of very similar pattern were detected between prewarm-up session myotonia phase and post-warm-up session myotonia absent phase in the group of patients with apparent grip myotonia.
We showed that myotonia is related to cortical function in high-order motor control areas. This cortical involvement is most likely to represent action of inhibitory circuits intending motor termination.
1型强直性肌营养不良症（DM1）是一种常见的成人肌肉萎缩症，其特征为肌肉萎缩、肌强直和多系统表现。肌强直期间的非自主肌肉收缩现象为研究脑运动功能提供了独特的可能性。本研究探讨DM1患者握力性肌强直期间大脑皮层的参与情况。
16例DM1患者纳入本研究。8例患者有明显的握力性肌强直，8例患者无明显握力性肌强直（对照组）。所有患者均接受两次功能性磁共振成像握力任务检查：一次在热身程序之前（有明显握力性肌强直的患者诱发肌强直），一次在热身程序之后（有明显握力性肌强直的患者肌强直减弱）。无明显握力性肌强直的患者在两次检查中均未诱发肌强直。比较了有和无明显肌强直的两组之间以及热身前后阶段的脑血氧水平依赖（BOLD）信号。
与无明显握力性肌强直患者相应的非肌强直阶段相比，有明显握力性肌强直的患者在肌强直阶段时，辅助运动区和背侧前扣带回皮层的BOLD信号显著更高。在有明显握力性肌强直的患者组中，热身前阶段的肌强直期与热身后阶段的无肌强直期之间检测到非常相似模式的BOLD信号水平存在显著差异。
我们表明肌强直与高级运动控制区域的皮层功能有关。这种皮层参与很可能代表了意图终止运动的抑制性回路的作用。
