RESUMO
BACKGROUND: Mirror therapy (MT) is becoming an alternative rehabilitation strategy for various conditions, including stroke. Although recent studies suggest the positive benefit of MT in chronic stroke motor recovery, little is known about its neural mechanisms. PURPOSE: To identify functional brain changes induced by a single MT intervention in ischemic stroke survivors, assessed by both transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI). MATERIALS AND METHODS: TMS and fMRI were used to investigate 15 stroke survivors immediately before and after a single 30-min MT session. RESULTS: We found statistically significant increase in post-MT motor evoked potential (MEP) amplitude (increased excitability) from the affected primary motor cortex (M1), when compared to pre-MT MEP. Post-MT fMRI maps were associated with a more organized and constrained pattern, with a more focal M1 activity within the affected hemisphere after MT, limited to the cortical area of hand representation. Furthermore, we find a change in the balance of M1 activity toward the affected hemisphere. In addition, significant correlation was found between decreased fMRI ß-values and increased MEP amplitude post-MT, in the affected hemisphere. CONCLUSION: Our study suggests that a single MT intervention in stroke survivors is related to increased MEP of the affected limb, and a more constrained activity of the affected M1, as if activity had become more constrained and limited to the affected hemisphere.
Assuntos
Isquemia Encefálica/reabilitação , Potencial Evocado Motor/fisiologia , Córtex Motor/fisiopatologia , Avaliação de Resultados em Cuidados de Saúde , Reabilitação do Acidente Vascular Cerebral/métodos , Acidente Vascular Cerebral/terapia , Extremidade Superior/fisiopatologia , Idoso , Isquemia Encefálica/complicações , Isquemia Encefálica/diagnóstico por imagem , Isquemia Encefálica/fisiopatologia , Doença Crônica/reabilitação , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Córtex Motor/diagnóstico por imagem , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/fisiopatologia , Estimulação Magnética TranscranianaRESUMO
Motor rehabilitation of stroke survivors may include functional and/or nonfunctional strategy. The present study aimed to compare the effect of these two rehabilitation strategies by means of clinical scales and functional Magnetic Resonance Imaging (fMRI). Twelve hemiparetic chronic stroke patients were selected. Patients were randomly assigned a nonfunctional (NFS) or functional (FS) rehabilitation scheme. Clinical scales (Fugl-Meyer, ARA test, and modified Barthel) and fMRI were applied at four moments: before rehabilitation (P1) and immediately after (P2), 1 month after (P3), and three months after (P4) the end of rehabilitation. The NFS group improved significantly and exclusively their Fugl-Meyer scores at P2, P3, and P4, when compared to P1. On the other hand, the FS group increased significantly in Fugl-Meyer at P2, when compared to P1, and also in their ARA and Barthel scores. fMRI inspection at the individual level revealed that both rehabilitation schemes most often led to decreased activation sparseness, decreased activity of contralesional M1, increased asymmetry of M1 activity to the ipsilesional side, decreased perilesional activity, and decreased SMA activity. Increased M1 asymmetry with rehabilitation was also confirmed by Lateralization Indexes. Our clinical analysis revealed subtle differences between FS and NFS.