Inhibition versus facilitation of contralesional motor cortices in stroke:Deriving a model to tailor brain stimulation

Approaches are not good enough, we need PROTOCOLS. WHEN THE HELL WILL YOU GET THERE?  Maybe when you are the 1 in 4 per WHO having a stroke?

Inhibition versus facilitation of contralesional motor cortices in stroke:Deriving a model to tailor brain stimulation

  Inhibition versus facilitation of contralesional motor cortices in stroke:Vishwanath Sankarasubramanian a, Andre G. Machado b, Adriana B. Conforto c,d, Kelsey A. Potter-Baker a,David A. Cunningham a,e, Nicole M. Varnerin a, Xiaofeng Wang f , Ken Sakaie g, Ela B. Plow a b h ⇑ a Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA bCenter for Neurological Restoration, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, USAc Neurology Clinical Division, Neurology Department, Hospital das Clinicas, São Paulo University, 05508-090 São Paulo, SP, Brazil dHospital Israelita Albert Einstein, 05652-900 São Paulo, SP, Brazil e School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA f Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA g Department of Diagnostic Radiology, Imaging Institute, Cleveland Clinic, Cleveland, OH 44195, USA h Department of Physical Medicine and Rehabilitation, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, USA a r t i c l e i n f o Article history:Accepted 14 March 2017 Available online 21 March 2017Keywords: Diffusion tensor imaging Motor cortex Premotor cortexNeuronal plasticity Rehabilitation Stroke Transcranial magnetic stimulation highlights Mildly affected chronic stroke patients improved upon paretic upper limb reaching with standard inhibitory 1Hz rTMS of contralesional motor cortex.   Severely affected patients improved with a new method involving facilitatory 5Hz rTMS of contralesional dorsal premotor cortex.   A preliminary cut-off level of damage/impairment separated responders to each form of stimulation.

abstract 

Objective:  The standard approach to brain stimulation in stroke is based on the premise that ipsilesional M1(iM1)is important for motor function of the paretic upper limb,while contralesional cortices compete with iM1. Therefore, the approach typically advocates facilitating iM1 and/or inhibiting contralesional M1 (cM1). But, this approach fails to elicit much improvement in severely affected patients, who on account of extensive damage to ipsilesional pathways, cannot rely on iM1. These patients are believed to instead rely on the undamaged cortices, especially the contralesional dorsal premotor cortex(cPMd), for support of function of the paretic limb. Here, we tested for the first time whether facilitation of cPMd could improve paretic limb function in severely affected patients, and if a cut-off could be identified to separate responders to cPMd from responders to the standard approach to stimulation.
Methods:  In a randomized, sham-controlled crossover study, fifteen patients received the standard; using repetitive transcranial magnetic stimulation (rTMS). Patients also received rTMS to control areas.At baseline, impairment [Upper Extremity Fugl-Meyer (UEFM PROXIMAL , max=36)] and damage to pathways [fractional anisotropy (FA)] was measured. We measured changes in time to perform proximal paretic limb reaching, and neurophysiology using TMS.
Results:  Facilitation of cPMd generated more improvement in severely affected patients, who had experienced greater damage and impairment than a cut-off value of FA (0.5) and UEFM PROXIMAL   (26–28). The standard approach instead generated more improvement in mildly affectedpatients.Responders tocPMd showed alleviation of interhemispheric competition imposed on iM1, while responders to the standard approach showed gains in ipsilesional excitability in association with improvement. Conclusions:  A preliminary cut-off level of severity separated responders for standard approach vs. facilitation of cPMd.