Rogić Vidaković Maja, Šoda Joško, Jerković Ana, Benzon Benjamin, Bakrač Karla, Dužević Silvia, Vujović Igor, Mihalj Mario, Pecotić Renata, Valić Maja, Mastelić Angela, Hagelien Maximilian Vincent, Zmajević Schőnwald Marina, Đogaš Zoran
University of Split, School of Medicine, Department of Neuroscience, Laboratory for Human and Experimental Neurophysiology (LAHEN), Split, Croatia.
University of Split, Faculty of Maritime Studies, Signal Processing, Analysis and Advanced Diagnostics Research and Education Laboratory (SPAADREL), Split, Croatia.
Nat Sci Sleep. 2020 Aug 6;12:563-574. doi: 10.2147/NSS.S253281. eCollection 2020.
An increase in resting motor threshold (RMT), prolonged cortical silent period duration (CSP), and reduced short-latency afferent inhibition (SAI), confirmed with previous transcranial magnetic stimulation (TMS), suggest decreased cortical excitability in obstructive sleep apnea syndrome (OSAS). The present study included MRI of OSAS patients for navigated TMS assessment of the RMT, as an index of the threshold for corticospinal activation at rest, and SAI as an index of cholinergic neurotransmission. We hypothesize to confirm findings on SAI and RMT with adding precision in the targeting of motor cortex in OSAS.
After acquiring head MRIs for 17 severe right-handed OSAS and 12 healthy subjects, the motor cortex was mapped with nTMS to assess the RMT and SAI, with motor evoked potentials (MEPs) recorded from the abductor-pollicis brevis (APB) muscle. The 120%RMT intensity was used for the SAI by a paired-pulse paradigm in which the electrical stimulation to the median nerve is followed by magnetic stimulation of the motor cortex at inter-stimulus intervals (ISIs) of 18-28 ms (ISIs). The SAI control condition included a recording of MEPs without peripheral stimulation. Latency and amplitude of MEP at RMT at 120%RMT for eleven different at ISIs were analyzed.
The study showed a significantly lower percentage deviation of MEP amplitude at ISIs from the control condition between OSAS and healthy subjects (U=44.0, p=0.01). The intensity of stimulation at RMT was significantly higher in OSAS subjects (U=55.0, p=0.04*). Correlation analysis showed that BMI significantly negatively correlated (=-0.47) with MEP amplitude percentage deviation in OSAS patients.
The nTMS study results in increased RMT, and reduced cortical afferent inhibition in OSAS patients for SAI at ISIs, confirming previous findings of impaired cortical afferent inhibition in OSAS. Future nTMS studies are desirable to elucidate the role of RMT and SAI in diagnostics and treatment of OSAS, and to elucidate the usefulness of nTMS in OSAS research.
经颅磁刺激（TMS）证实，静息运动阈值（RMT）升高、皮质静息期时长（CSP）延长以及短潜伏期传入抑制（SAI）降低，提示阻塞性睡眠呼吸暂停综合征（OSAS）患者的皮质兴奋性降低。本研究纳入了OSAS患者的MRI检查，用于导航TMS评估RMT（作为静息时皮质脊髓激活阈值的指标）以及SAI（作为胆碱能神经传递的指标）。我们假设通过在OSAS患者中更精确地靶向运动皮层来证实关于SAI和RMT的研究结果。
对17名重度右利手OSAS患者和12名健康受试者进行头部MRI检查后，使用导航TMS绘制运动皮层图，以评估RMT和SAI，并从拇短展肌（APB）记录运动诱发电位（MEP）。SAI采用配对脉冲范式，以120%RMT强度进行，即先对正中神经进行电刺激，然后在18 - 28毫秒的刺激间隔（ISI）对运动皮层进行磁刺激。SAI对照条件包括在无外周刺激的情况下记录MEP。分析了在120%RMT时，针对11种不同ISI的RMT下MEP的潜伏期和波幅。
研究表明，OSAS患者与健康受试者相比，在ISI时MEP波幅与对照条件相比的百分比偏差显著更低（U = 44.0，p = 0.01）。OSAS受试者的RMT刺激强度显著更高（U = 55.0，p = 0.04*）。相关性分析表明，在OSAS患者中，体重指数（BMI）与MEP波幅百分比偏差显著负相关（r = -0.47）。
导航TMS研究结果显示，OSAS患者的RMT升高，且在ISI时SAI的皮质传入抑制降低，证实了先前关于OSAS患者皮质传入抑制受损的研究结果。未来需要进行更多导航TMS研究，以阐明RMT和SAI在OSAS诊断和治疗中的作用，并阐明导航TMS在OSAS研究中的实用性。
