γ-Aminobutyric acid (GABA) plays a key role in motor learning. In the aftermath of stroke, we monitored GABA+ content of primary motor cortex by magnetic resonance spectroscopy (MRS), assessing its relation to functional motor recovery following a standardized 4-week program of rehabilitation. The cohort included 20 patients, each experiencing stroke within 2 weeks of symptom onset. Twenty age-matched healthy subjects were also recruited as controls. GABA+ levels were determined at baseline and following rehabilitation, performed only once in sex- and age-matched control subjects. Motor functions were then measured via Fugl-Meyer Assessment (FMA). Processing of MRS data was driven by open-source Gannet software. Because GABA, macromolecules, and homocarnosine jointly contribute to MEscher-Garwood Point RESolved Spectroscopy (MEGA-PRESS) signals, the designation GABA+ (rather than GABA) was applied. Baseline GABA+/creatine (Cr) ratios proved significantly lower in patients with strokes than in control subjects (P<0.05). Following the 4-week rehabilitative regimen, significant improvement in FMA indices was evident across the test group. FMA scores and GABA+/Cr ratios correlated significantly at baseline, the GABA+/Cr ratio displaying a significant association with motor function (P=0.025). In the setting of acute stroke, GABA+/Cr ratios of primary motor cortex fell significantly below levels found in healthy subjects. The observed association between GABA+/Cr ratio and motor recovery underscores the utility of MRS-measured GABA as a key motor recuperative biomarker.
Keywords: GABA; Stroke; magnetic resonance spectroscopy; rehabilitation.
AJTR Copyright © 2020.