Oasi Research Institute - IRCCS, Via Conte Ruggero, 73, 94018, Troina, Italy.
Department of Medical and Surgical Sciences and Advanced Technologies "GF Ingrassia", Section of Neurosciences, Azienda Ospedaliero Universitaria "Policlinico-Vittorio Emanuele", Via Santa Sofia, 78, 95125, Catania, Italy.
Sleep Med. 2018 Jun;46:1-4. doi: 10.1016/j.sleep.2018.02.008. Epub 2018 Mar 8.
Previous studies showed an impairment of the LTP-like plasticity to TMS in restless legs syndrome (RLS). Clinically, repetitive TMS (rTMS) was effective in alleviating the sensory-motor complaints of patients, although the effects induced by low-frequency (inhibitory) rTMS have not yet been investigated. An impaired LTD-like mechanism of cortical plasticity has been hypothesized, which we have directly assessed in this pilot study.
Motor evoked potentials (MEPs) from the right first dorsal interosseus muscle were recorded at the stimulus intensity of 110% of the resting motor threshold (rMT) from 13 right-handed patients and ten age-matched right-handed healthy controls. Median peak-to-peak amplitudes were calculated in all participants at baseline (T), after the first train of a single evening session of low-frequency (1 Hz) rTMS over the left primary motor cortex (T), and after the whole rTMS procedure (T), which consists of 20 trains with 50 stimuli per train and intertrain interval of 30 s (1000 stimuli in total).
No differences were found for rMT and MEPs size between the two groups at T. Smaller MEPs amplitudes at both T and T were observed in all subjects, although this was significantly more pronounced in controls than in patients.
Compared to normal individuals, patients exhibited an impairment of the LTD-like mechanisms induced by inhibitory rTMS, thus adding support to the involvement of GABA in RLS pathophysiology. Although future studies with a larger population are needed, TMS is confirmed to be effective in noninvasive probing of the neurophysiology and neurochemistry of RLS.
先前的研究表明，不安腿综合征（RLS）患者的 TMS 诱导长时程增强（LTP）样可塑性受损。临床上，重复经颅磁刺激（rTMS）对缓解患者的感觉运动症状有效，尽管尚未研究低频（抑制性）rTMS 诱导的作用。有人假设皮质可塑性存在 LTD 样机制受损，我们在这项初步研究中直接评估了这一机制。
从 13 名右利手患者和 10 名年龄匹配的右利手健康对照者的右侧第一背间骨间肌记录刺激强度为静息运动阈值（rMT）的 110%的运动诱发电位（MEP）。在基线（T）、单次左初级运动皮层低频（1 Hz）rTMS 第一串刺激后（T）以及整个 rTMS 过程后（T）（总共 20 串，每串 50 个刺激，串间间隔 30 秒，总共 1000 个刺激），计算所有参与者的中峰-峰振幅。
在 T 时，两组的 rMT 和 MEP 大小无差异。在所有受试者中，T 和 T 时的 MEP 振幅均较小，但在对照组中比在患者中更为明显。
与正常个体相比，患者表现出抑制性 rTMS 诱导的 LTD 样机制受损，从而为 GABA 在 RLS 病理生理学中的作用提供了更多支持。尽管需要进行更大人群的未来研究，但 TMS 被证实可有效无创探查 RLS 的神经生理学和神经化学。
