Oscillatory MEG motor activity reflects therapy-related plasticity in stroke patients.
BACKGROUND
A goal of stroke rehabilitation is to harness the capacity of the brain to reorganize following neurological damage and enable restoration of function.


OBJECTIVE
To understand how neural oscillatory motor responses change following a therapeutic intervention and to illuminate whether these neurophysiological alterations correlate with improvements on behavioral measurements.


METHODS
Magnetoencephalography (MEG) was used to evaluate plasticity in motor networks following 2 weeks of intensive task-oriented therapy, which was paired with sham or peripheral nerve stimulation (PNS). Patients completed unilateral finger tapping before and 3 weeks after therapy as whole-head MEG data were acquired. MEG data were imaged using beamforming, and the resulting event-related synchronizations and desynchronizations (ERSs/ERDs) were subjected to region-of-interest (ROI) analyses. For each ROI, the authors compared the baseline and postintervention MEG response amplitude, volume, and peak location for premovement β ERD, movement-onset γ ERS, and postmovement β ERS.


RESULTS
Following therapy, all patients showed reduced postmovement β ERS response amplitudes in bilateral precentral gyri and reduced γ ERS amplitudes in the precentral gyrus of the affected hemisphere. This latter response also distinguished treatment groups, as the posttherapy γ reduction was greater in patients who received PNS. Finally, both β and γ response amplitudes were significantly correlated with improvement on several behavioral indices of motor function.


CONCLUSIONS
These case-series data indicate that oscillatory MEG responses may be useful in gauging plasticity in motor cortices following therapy in stroke patients.
Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA. Tony.W.Wilson@gmail.com
Tony W
TW
Wilson
Anne
A
Fleischer
Darlene
D
Archer
Satoru
S
Hayasaka
Lumy
L
Sawaki
D001683:Biological Clocks / Q000502:physiology; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology*; D010291:Paresis / Q000503:physiopathology / Q000534:rehabilitation*; D020521:Stroke / Q000503:physiopathology; D000071939:Stroke Rehabilitation