OBJECTIVE A recent "bimodal-balance recovery" model suggests that contralesional influence varies based on the amount of ipsilesional reserve: inhibitory when there is a large reserve, but supportive when there is a low reserve. Here, we investigated the relationships between contralesional influence (inter-hemispheric inhibition, IHI) and ipsilesional reserve (corticospinal damage/impairment), and also defined a criterion separating subgroups based on the relationships. METHODS Twenty-four patients underwent assessment of IHI using Transcranial Magnetic Stimulation (ipsilateral silent period method), motor impairment using Upper Extremity Fugl-Meyer (UEFM), and corticospinal damage using Diffusion Tensor Imaging and active motor threshold. Assessments of UEFM and IHI were repeated after 5-week rehabilitation (n = 21). RESULTS Relationship between IHI and baseline UEFM was quadratic with criterion at UEFM 43 (95%conference interval: 40-46). Patients less impaired than UEFM = 43 showed stronger IHI with more impairment, whereas patients more impaired than UEFM = 43 showed lower IHI with more impairment. Of those made clinically-meaningful functional gains in rehabilitation (n = 14), more-impaired patients showed further IHI reduction. CONCLUSIONS A criterion impairment-level can be derived to stratify patient-subgroups based on the bimodal influence of contralesional cortex. Contralesional influence also evolves differently across subgroups following rehabilitation. SIGNIFICANCE The criterion may be used to stratify patients to design targeted, precision treatments.

中文翻译：

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根据对侧运动皮质的影响对慢性中风患者进行分层：半球间抑制研究


目的 最近的“双峰平衡恢复”模型表明，对侧影响根据同侧储备量的不同而变化：当储备量较大时，抑制作用，而当储备量较低时，则产生支持作用。在这里，我们研究了对侧影响（半球间抑制，IHI）和同侧储备（皮质脊髓损伤/损伤）之间的关系，并根据这些关系定义了区分亚组的标准。方法 24 名患者接受了使用经颅磁刺激（同侧静默期法）的 IHI 评估、使用上肢 Fugl-Meyer (UEFM) 的运动损伤评估以及使用弥散张量成像和主动运动阈值的皮质脊髓损伤评估。 5 周康复后重复进行 UEFM 和 IHI 评估 (n = 21)。结果 IHI 和基线 UEFM 之间的关系与 UEFM 43（95% 会议间隔：40-46）的标准呈二次关系。受损程度低于 UEFM = 43 的患者表现出更强的 IHI 且受损程度更高，而受损程度高于 UEFM = 43 的患者则表现出较低的 IHI 且受损程度更高。在那些在康复过程中获得具有临床意义的功能改善的患者中（n = 14），受损程度较高的患者的 IHI 进一步降低。结论 根据对侧皮层的双峰影响，可以得出标准损伤水平来对患者亚组进行分层。康复后，不同亚组的对侧影响也有不同的演变。意义 该标准可用于对患者进行分层，以设计有针对性的精准治疗。