Contralesional Cathodal versus Dual Transcranial Direct Current Stimulation for Decreasing Upper Limb Spasticity in Chronic Stroke Individuals: A Clinical and Neurophysiological Study.
BACKGROUND
Different transcranial direct current stimulation (tDCS) paradigms have been implemented to treat poststroke spasticity, but discordant results have been reported.


OBJECTIVE
This study aimed to determine the efficacy and persistence of dual tDCS (anode over affected motor cortex [M1] and cathode over contralateral M1) compared with cathodal tDCS (cathode over contralateral M1) on upper limb (UL) functional, behavioral, and neurophysiological measures in chronic poststroke individuals.


METHODS
Ten subjects with UL spasticity (7 men; mean 62 years; 8 ischemic stroke; years from event: 2.3 years) were enrolled in a cross-over, double-blinded study. Cathodal and dual tDCS, both preceded by 1 week of sham stimulation 1 month before real stimulation, were applied with 3 months interval. Stimulating paradigm was 20 minutes for five consecutive days in each block. Evaluations were performed before (T1), after real or sham treatment (T2), and after 1 (T3), 4 (T4), and 8 weeks (T5). Functional, behavioral, and neurophysiological tests were performed at each time.


RESULTS
Both tDCS paradigms decreased spasticity, increased strength, and ameliorated behavioral scales. Cathodal tDCS was superior to dual tDCS in reducing UL distal spasticity immediately after treatment (T2: cathodal > dual: P = .023) and provided a higher and longer lasting reduction at proximal districts (T3: cathodal > dual: P = .042; T4: cathodal > dual: P = .028; T5: cathodal > dual: P = .05). These findings are supported by an H-reflex modulation (overall time effect P > .002).


CONCLUSIONS
Cathodal tDCS is slightly more effective than dual tDCS in reducing distal UL spasticity in chronic poststroke subjects. A modulation of spinal inhibitory mechanisms, demonstrated by H-reflex modifications, supports this finding.
Department of Neuroscience, Section of Rehabilitation, University of Padova, Italy. Electronic address: alessandra.delfelice@unipd.it.
Alessandra
A
Del Felice
Rehabilitation Section, Hospital of Bolzano, Bolzano, Italy.
Verena
V
Daloli
Department of Neuroscience, Section of Rehabilitation, University of Padova, Italy.
Stefano
S
Masiero
Department of Neurology, University Hospital, Trieste, Italy.
Paolo
P
Manganotti
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D018592:Cross-Over Studies; D004185:Disability Evaluation; D004311:Double-Blind Method; D005260:Female; D006181:H-Reflex; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009044:Motor Cortex / Q000503:physiopathology*; D009128:Muscle Spasticity / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology / Q000534:rehabilitation*; D053580:Muscle Strength; D009460:Neurologic Examination; D009483:Neuropsychological Tests; D020127:Recovery of Function; D020521:Stroke / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D000071939:Stroke Rehabilitation / Q000379:methods*; D013997:Time Factors; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D016896:Treatment Outcome; D034941:Upper Extremity / Q000294:innervation*
Hemispheric imbalance; ischemic stroke; motor rehabilitation; non-invasive brain stimulation