Lacerda Guilherme J M, Camargo Lucas, Silva Fernanda M Q, Imamura Marta, Battistella Linamara R, Fregni Felipe
Instituto de Medicina Física e Reabilitação, Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo 04116-030, SP, Brazil.
Neuromodulation Center, Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA 02115, USA.
Biomedicines. 2025 Apr 22;13(5):1015. doi: 10.3390/biomedicines13051015.
: Lower-limb amputation (LLA) leads to disability, impaired mobility, and reduced quality of life, affecting 1.6 million people in the USA. Post-amputation, motor cortex reorganization occurs, contributing to phantom limb pain (PLP). Transcranial magnetic stimulation (TMS) assesses changes in cortical excitability, helping to identify compensatory mechanisms. This study investigated the association between TMS metrics and clinical and neurophysiological outcomes in LLA patients. : A cross-sectional analysis of the DEFINE cohort, with 59 participants, was carried out. TMS metrics included resting motor threshold (rMT), motor-evoked potential (MEP) amplitude, short intracortical inhibition (SICI), and intracortical facilitation (ICF). : Multivariate analysis revealed increased ICF and rMT in the affected hemisphere of PLP patients, while SICI was reduced with the presence of PLP. A positive correlation between SICI and EEG theta oscillations in the frontal, central, and parietal regions suggested compensatory mechanisms in the unaffected hemisphere. Increased MEP was associated with reduced functional independence. : SICI appears to be a key factor linked to the presence of PLP, but not its intensity. Reduced SICI may indicate impaired cortical compensation, contributing to PLP. Other neural mechanisms, including central sensitization and altered thalamocortical connectivity, may influence PLP's severity. Our findings align with those of prior studies, reinforcing low SICI as a marker of maladaptive neuroplasticity in amputation-related pain. Additionally, longer amputation duration was associated with disrupted SICI, suggesting an impact of long-term plasticity changes.
下肢截肢（LLA）会导致残疾、行动能力受损和生活质量下降，在美国影响着160万人。截肢后，运动皮层会发生重组，导致幻肢痛（PLP）。经颅磁刺激（TMS）可评估皮层兴奋性的变化，有助于识别代偿机制。本研究调查了LLA患者中TMS指标与临床及神经生理学结果之间的关联。：对DEFINE队列中的59名参与者进行了横断面分析。TMS指标包括静息运动阈值（rMT）、运动诱发电位（MEP）幅度、短皮质内抑制（SICI）和皮质内易化（ICF）。：多变量分析显示，PLP患者患侧半球的ICF和rMT增加，而PLP存在时SICI降低。额叶、中央区和顶叶区域的SICI与脑电图θ振荡之间呈正相关，提示未受影响半球存在代偿机制。MEP增加与功能独立性降低相关。：SICI似乎是与PLP存在相关的关键因素，但与PLP强度无关。SICI降低可能表明皮质代偿受损，导致PLP。其他神经机制，包括中枢敏化和丘脑皮质连接改变，可能影响PLP的严重程度。我们的研究结果与先前的研究一致，强化了低SICI作为截肢相关疼痛中适应不良神经可塑性标志物的地位。此外，截肢时间越长与SICI中断相关，表明长期可塑性变化的影响。
