Bi-Hemispheric Repetitive Transcranial Magnetic Stimulation For Upper Limb Motor Recovery In Chronic Stroke: A Feasibility Study
Journal: Brain Stimulation 11(4):932-934 (2018)
Authors: R Chieffo, G Scopelliti, M Fichera, R Santangelo, S Guerrieri, A Zangen, G Comi, L Leocani
The emerging crucial role of non-primary and contralesional motor areas in the recovery of upper extremity (UE) after acute stroke led to the proposal of the “bimodal-balance recovery model”, with the hypothesis that the contribution of ipsi-and contralesional primary and secondary motor areas might vary according to the structural reserve of the ipsilesional cortico-spinal tract. This model offers itselfto novel non-invasive brain stimulation approaches for improving the effects of neurorehabilitation, targeting bilateral, wide motor cortical regions rather than focusing on the ipsilateral or contralesional M1.
To test the safety, feasibilityand efficacy of simultaneous high-frequency rTMS of bilateral motor/premotor areas using the H5-coil, associated with unilateral motor training of the paretic UE.
Twenty patients with UE motor involvement from first-ever chronic stroke under went 11 sessions of 30 minutes of upper limb motor training (MT) of the paretic UE, each followed by rTMS with the symmetric H5-coil, designed to stimulate both hemispheres simultaneously(40 2s-trains at 20 Hz, 20 sec inter-train interval, 1600 pulses), at 90% of resting motor threshold (RMT). Clinical measurements were collected before the first (T0) and after the last treatment session (T1), plus one-month follow-up (T2) and included: FM-UE score, modified Ashworth scale (MAS) global score as the sum of shoulder, elbow and wrist scores (range 0-12), hand grip strength (JAMAR dynamometer).
In this study that included participants with mild to severe-moderate UE motor impairment, bilateral high-frequency rTMS of motor/premotor areas, following motor training, was associated with greater and more sustained motor improvement compared with motor training followed by sham. Such improvement was clinically relevant (FM-UE6 point) for 70% of subjects in the real group (vs 10%of the sham group).Interestingly, the investigators found that bilateral stimulation of motor/premotor areas was associated with a greater FM-UE improvement in more severely impaired patients, opposite to what observed in the sham group.
It is possible that the wide bilateral, simultaneous stimulation may improve functional intra-and interhemispheric synchronization between motor and premotor areas and promote the unmasking of cortico-cortical and descending pathways