Comparison of neuroplastic responses to cathodal transcranial direct current stimulation and continuous theta burst stimulation in subacute stroke

Publication date: Available online 7 December 2017
Source:Archives of Physical Medicine and Rehabilitation
Author(s): Pierre Nicolo, Cécile Magnin, Elena Pedrazzini, Gijs Plomp, Anaïs Mottaz, Armin Schnider, Adrian G. Guggisberg
ObjectiveTo investigate the effects of cathodal transcranial direct current stimulation (tDCS) and continuous theta burst stimulation (cTBS) on neural network connectivity and motor recovery in individuals with subacute stroke.DesignDouble-blinded, randomized, placebo-controlled study.SettingStroke subjects recruited through a university hospital rehabilitation program.ParticipantsStroke inpatients (N=41; mean age 65y, range 28-85; mean weeks poststroke 5, range 2-10) with resultant paresis in the upper extremity (mean Fugl-Meyer score 14, range 3-48).InterventionStroke subjects were randomly assigned to neuronavigated cTBS (N=14), cathodal tDCS (N=14), or sham TMS/sham tDCS (N=13) over the contralesional primary motor area (M1). Each subject completed nine stimulation sessions over three weeks, combined with physical therapy.Main outcome measuresBrain function was assessed with resting-state directed and non-directed functional connectivity based on high-density electroencephalography (EEG) before and after stimulation sessions. Primary clinical endpoint was the change in slope of multifaceted motor score composed of the Upper-Extremity Fugl-Meyer Assessment (UE-FMA), Box and Block test (BBT), Nine Hole Peg Test (NHPT), Jamar dynamometer between the baseline period and the treatment time.ResultsNeither stimulation treatment enhanced clinical motor gains. Cathodal tDCS and cTBS induced different neural effects. Only cTBS was able to reduce transcallosal influences from the contralesional to the ipsilesional M1 during rest. Conversely, tDCS enhanced perilesional beta-band oscillation coherence as compared to cTBS and sham groups. Correlation analyses indicated that the modulation of interhemispheric driving and perilesional beta-band connectivity were not independent mediators for functional recovery across all patients. However, exploratory subgroup analyses suggest that the enhancement of perilesional beta-band connectivity through tDCS might have more robust clinical gains if started within the first 4 weeks after stroke.ConclusionsThe inhibition of the contralesional primary motor cortex or the reduction of interhemispheric interactions was not clinically useful in heterogeneous group of subacute stroke subjects. An early modulation of perilesional oscillation coherence seems to be a more promising strategy for brain stimulation interventions.



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