Distribution of muscle stretch injury in contractured muscles in rats

Methods: Twenty acute stroke patients were randomized into rTMS group or sham group. Patients received 5 daily sessions of 1Hz rTMS or sham rTMS over the intact motor cortex. For recording MRCP, patients performed self-paced wrist dorsiflexion of affected limb before and after rTMS sessions. Electrodes were placed at Fz, FC3, FCz, FC4, C3, Cz, C4 and Pz according to the international 10–20 system. MRCPwas divided into 3 components of Bereitschaft potential (BP), negative slope (NS’) and motor potential (MP). For behavioral testing, patients performed the upper extremity Fugl-Meyer Assessment (FMA), pegboard test, and grip strength before and after rTMS sessions. TheMRCP data and behavioral data were subjected to repeated measures analysis of variance (ANOVA) using time (pre-rTMS and post-rTMS) as within-subject factors and group (rTMS group and sham group) as a between-subject factor. Pearson correlation coefficient or Spearman’s rank correlation coefficient was used to assess associations between MRCP and motor function data. Results: MRCP showed a significant increase of MP amplitude at C and FC sites in affected hemisphere after rTMS to the contralesional motor cortex for five days (Ps < 0.05). At the same time, there were increases of NS’ amplitude at C and FC sites in affected hemisphere and at Cz site (Ps < 0.05). The behavioral data showed significant improvement of FMA and PPT in the rTMS group compared to the sham group (Ps < 0.02). The improvement of FMA for upper limbmotor functionwas correlatedwith the increase of MRCPamplitude recorded over the ipsilesionalmotor cortex. Conclusion(s): Low-frequency rTMS to contralesional motor cortex promoted motor functional recovery of upper extremity for acute stroke patients, and this improvement was associated with enhanced movement-related electrophysiological activity of affected motor cortex possibly through suppression of transcallosal inhibition. Implications: Low-frequency rTMS to non-affected hemisphere may be promising intervention for motor recovery even in acute stroke patients with hemiparesis.