Recovery of post stroke proximal arm function, driven by complex neuroplastic bilateral brain activation patterns and predicted by baseline motor dysfunction severity

Abstract

Objectives: Neuroplastic changes that drive recovery of shoulder/elbow function after stroke have been poorly understood. The purpose of this study was to determine the relationship between neuroplastic brain changes related to shoulder/elbow movement control in response to treatment and recovery of arm motor function in chronic stroke survivors.Methods: Twenty-three chronic stroke survivors were treated with 12 weeks of arm rehabilitation. Outcome measures included functional Magnetic Resonance Imaging (fMRI) for the shoulder/elbow components of reach and a skilled motor function test (Arm Motor Abilities Test, AMAT), collected before and after treatment.Results: We observed two patterns of neuroplastic changes that were associated with gains in motor function: decreased or increased task-related brain activation. Those with significantly better motor function at baseline exhibited a decrease in brain activation in response to treatment, evident in the ipsilesional primary motor and contralesional supplementary motor regions; in contrast, those with greater baseline motor impairment, exhibited increased brain activation in response to treatment. There was a linear relationship between greater functional gain (AMAT) and increased activation in bilateral primary motor, contralesional primary and secondary sensory regions, and contralesional lateral premotor area, after adjusting for baseline AMAT, age, and time since stroke.Conclusions: Recovery of functional reach involves recruitment of several contralesional and bilateral primary motor regions. In response to intensive therapy, the direction of functional brain change (i.e., increase or decrease in task-related brain recruitment) for shoulder/elbow reach components depends on baseline level of motor function and may represent either different phases of recovery or different patterns of neuroplasticity that drive functional recovery.

Physiotherapy based on problem‐solving in upper limb function and neuroplasticity in chronic stroke patients: A case series

“…However, this can also be observed after normal aging, ie, a recruitment of additional areas, in particular in the ipsilateral/contralesional hemisphere, justifying the similar results in healthy subjects. The success of recovery in chronic patients involved the recruitment of alternative single or multiple functional brain regions in contralateral/ipsilesional and ipsilateral/contralesional hemispheres …”

“…A previous study revealed similar decreases in brain activation across multiple scan sessions, but only in recent patients and not controls, signifying overactivation in primary and secondary motor areas at baseline, which seems to be present in the chronic phase. Two different patterns of brain activation changed, ie, increased or decreased volume and the uniform or mixed patterns, were previously mentioned in stroke patients, after intervention, similar to what occurred in this study.…”

“…Some authors have mentioned that recruiting contralateral/ipsilesional M1 differs across patients in a way largely independent to the baseline function or deficit . While, more recently, others refer there are differences in fMRI changes regarding severity at baseline, ie, a decrease or increase in brain activation occurs according to better or worse motor function for proximal arm at baseline, respectively, especially in contralateral M1 and ipsilateral SMA which is independent of functional improvement . This suggest that the variability in our results was the consequence of our patient characteristics, ie, none had language or cognitive deficits needed to understand instructions; the severity at baseline, because some studies mentioned the strategy to recovery is different and age.…”

Spontaneous and Therapeutic-Induced Mechanisms of Functional Recovery After Stroke

“…Indeed, brain mapping studies show increased recruitment of contralesional motor, supplementary, and premotor cortical areas with voluntary movement from the stroke-affected extremity [91, 92, 70, 74, 85, 93–96]. The extent of contralesional hemisphere activation is typically predicated on the integrity of the corticospinal tract, with greater contralesional hemisphere activation associated with greater ipsilesional corticospinal tract injury [97–99].…”

Therapeutic applications of BCI technologies

“…Strategy 2 individuals began with greater dysfunction, according to the longer AMAT mean time shown in the M1 row for the Strategy 2 individuals versus the AMAT mean time shown in the M1 row for the Strategy 1 individuals, who required a shorter amount of time for the functional tasks of the AMAT. In other words, those with greater baseline impairment used Strategy 2, enlarging volume of brain activation with motor recovery; and those with less baseline impairment reduced or focused their brain activation patterns [57] in response to treatment and as they recovered. And it gets even more complicated, with each individual likely possessing a unique pattern of increase or decrease in volume of activation across 12 regions of interest studied (Table 2; we can note the different numbers of individuals, shown down the column of ROI’s for Strategy 2; that is, one given individual did not adhere to either Strategy 1 or 2 across their own ROI’s, as they recovered motor function).…”