Using fMRI imaging and a custom hand exercise robotic machine, Dr. A. Aria Tzika and colleagues from the NMR Surgical Laboratory at Massachusetts General Hospital have shown that chronic stroke patients, after undergoing rehabilitative exercises, were able to restore significant amount of brain function associated with the particular movement. The researchers call their robotic hand device a “second-generation prototype Magnetic Resonance Compatible Hand-Induced Robotic Device, or, MR_CHIROD.”
From the abstract presented at the annual meeting of Radiological Society of North America (RSNA):
METHOD AND MATERIALS
We evaluated 60 fMRI datasets at 3T from five right-hand-dominant patients (mean age: 65 years) with first-ever left-sided stroke ≥6 months prior and mild to moderate hemiparesis affecting the right hand. Patients trained the paretic hand at approximately 75% of maximum strength with an exercise ball for 1 hour/day, 3 days/week for 4 weeks. MR neuroimaging exams were performed before, during (A), upon completion of training (B), and after a non-training period (C) to assess permanence of effects. We acquired fMRI data using a block design paradigm and parallel imaging (GeneRalized Autocalibrating Partially Parallel Acquisitions, GRAPPA; TR/TE=3000ms/30ms, 1.56 mm×1.56 mm×3 mm) while the participant used the MR_CHIROD. During the action period, subjects continuously squeezed and released the MR_CHIROD at 0.5 Hz. Volunteers performed the paradigm at 45%, 60%, and 75% of maximum dynamic grip strength and could fully squeeze the device at all levels. Clusters of statistically significant voxels (P<0.05, corrected) were further selected for BOLD ≥ 2.0%. This 2.0% threshold served as a filter, selecting regions of interest without enforcing their boundaries a priori. Comparisons between effort levels were done using t-test (two-tailed, P<0.05).
Training significantly increased the number of activated voxels in the cortex as function of maximum effort. At 45% effort, A (mean number of activated voxels ± SD, 35 ± 15) differed from B (236 ± 32), P = 0.0022, and from C (246 ± 30), P = 0.0016. At the 60% effort, A (116 ± 31) differed significantly from B (271 ± 33), P < 0.05, and from C (271 ± 26), P < 0.05. At the 75% effort, A (180 ± 22) differed significantly from B (295 ± 38), P < 0.05, and from C (246 ± 20 voxels) P < 0.05.
Online fMRI using MR_CHIROD suggested that training-induced functional cortical plasticity persists even in chronic stroke patients indicating permanence of rehabilitation.
Top image: Left: An fMRI image illustrating the area in the brain that corresponds with a patient’s hand use before training. Effort levels are 45percent (top) and 60percent (bottom) of the patient’s maximum hand-strength. Right: An fMRI image illustrating the area in the brain that corresponds with a patient’s hand use after eight weeks of training. Effort levels are 45percent (top) and 60percent (bottom) of the patient’s maximum hand-strength. Side image: The second-generation prototype Magnetic Resonance Compatible Hand-Induced Robotic Device, or, MR_CHIROD. Credit: RSNA
Press release: Robotic Technology Improves Stroke Rehabilitation …