Department of Electrical, Electronic and Computer Engineering, University of Catania, 95125 Catania, Italy.
IEEE Trans Neural Syst Rehabil Eng. 2013 May;21(3):391-403. doi: 10.1109/TNSRE.2013.2256432. Epub 2013 Apr 3.
Major depression is one of the leading causes of disabling condition worldwide and its treatment is often challenging and unsatisfactory, since many patients become refractory to pharmacological therapies. Transcranial magnetic stimulation (TMS) is a noninvasive neurophysiological investigation mainly used to study the integrity of the primary motor cortex excitability and of the cortico-spinal tract. The development of paired-pulse and repetitive TMS (rTMS) paradigms has allowed investigators to explore the pathophysiology of depressive disorders and other neuropsychiatric diseases linked to brain excitability dysfunctions. Repetitive transcranial magnetic stimulation has also therapeutic and rehabilitative capabilities since it is able to induce changes in the excitability of inhibitory and excitatory neuronal networks that may persist in time. However, the therapeutic effects of rTMS on major depression have been demonstrated by analyzing only the improvement of neuropsychological performance. The aim of this study was to investigate cortical excitability changes on 12 chronically-medicated depressed patients (test group) after rTMS treatment and to correlate neurophysiological findings to neuropsychological outcomes. In detail, we assessed different parameters of cortical excitability before and after active rTMS in the test group, then compared to those of 10 age-matched depressed patients (control group) who underwent sham rTMS. In line with previous studies, at baseline both groups exhibited a significant interhemispheric difference of motor cortex excitability. This neurophysiological imbalance was then reduced in the patients treated with active rTMS, resulting also in a clinical benefit as demonstrated by the improvement in neuropsychological test scores. On the contrary, after sham rTMS, the interhemispheric difference was still evident in the control group. The reported clinical benefits in the test group might be related to the plastic remodeling of synaptic connection induced by rTMS treatment.
重度抑郁症是全球导致残疾的主要原因之一，其治疗常常具有挑战性且不尽如人意，因为许多患者对药物治疗产生抗药性。经颅磁刺激（TMS）是一种非侵入性的神经生理研究方法，主要用于研究初级运动皮层兴奋性和皮质脊髓束的完整性。成对脉冲和重复经颅磁刺激（rTMS）范式的发展使研究人员能够探索抑郁障碍和其他与大脑兴奋性功能障碍相关的神经精神疾病的病理生理学。重复经颅磁刺激还具有治疗和康复能力，因为它能够诱导抑制性和兴奋性神经元网络的兴奋性发生变化，这些变化可能会持续一段时间。然而，rTMS 对重度抑郁症的治疗效果仅通过分析神经心理表现的改善来证明。本研究的目的是在 rTMS 治疗后，研究 12 名慢性药物治疗的抑郁症患者（实验组）的皮质兴奋性变化，并将神经生理学发现与神经心理学结果相关联。具体而言，我们在实验组中评估了 rTMS 治疗前后皮质兴奋性的不同参数，然后将其与 10 名年龄匹配的接受假 rTMS 治疗的抑郁症患者（对照组）进行比较。与之前的研究一致，两组在基线时均表现出明显的运动皮层兴奋性的半球间差异。这种神经生理学失衡在接受主动 rTMS 治疗的患者中得到了缓解，这也导致了临床获益，如神经心理学测试分数的改善所示。相反，在接受假 rTMS 治疗后，对照组的半球间差异仍然明显。实验组中报告的临床获益可能与 rTMS 治疗诱导的突触连接的可塑性重塑有关。
