Does Excitatory rTMS Augment Functional Task Practice to Improve Arm Recovery Post-Stroke?

Research Report
Population: Adult

Dorian Kay Rose, PhD, PT, Research Assistant Professor, University of Florida

Carolynn Patten, PhD, PT, Associate Professor, University of Florida

Keywords: Plasticity, Stroke, Upper Extremity, Rehabilitation

Purpose/Hypothesis: The interhemispheric competition model proposes that the balance of cortical excitability between the two hemispheres is altered post-stroke leading to enhanced excitability of the contralesional primary motor cortex (M1) which exerts abnormally increased interhemispheric inhibition to the ipsilesional M1. High-frequency repetitive transcranial magnetic stimulation (rTMS) can be applied non-invasively to the ipsilesional M1 to up-regulate cortical excitability to restore this balance and in turn and may facilitate paretic upper extremity (UE) motor recovery. The purpose of this study was to test the hypothesis that high-frequency rTMS to the ipsilesional hemisphere administered immediately prior to exercise would serve to augment the effects of functional task practice (FTP) resulting in greater UE motor ability compared to FTP alone.

Subjects: Seventeen individuals post-stroke:13 male; mean age: 61.2±9.2 years; mean time post-stroke: 24.1±19.2 months.

Materials/Methods: Participants were randomized in this double-blind trial to receive either real-experimental (EXP (n=9)) or sham-control (CON) (n=8)) 10-Hz rTMS for 10 minutes (1000 pulses) to the ipsilesional hemisphere paired with 4 hours (2 hours therapist-directed, 2 hours prescribed independent program) of UE FTP 4x/week for 4 weeks. UE motor ability was evaluated by evaluators blinded to group assignment pre- and post-intervention with the Wolf Motor Function Test (WMFT), the UE Fugl-Meyer Assessment (FMA) and Grip dynamometry (Grip). Group differences in pre- post-intervention changes scores were tested using an independent sample t-test.

Results: At baseline there were no differences in age, time post-stroke, WMFT, FMA, or Grip between the two groups (p’s > 0.05).The median change in the WMFT score was greater for the EXP (22.6±14.5) compared to the CON (1.0±0.38) group (p < 0.05). No differences between the EXP or CON groups were detected in the FMA or Grip change scores (FMA: EXP 6.2±2.1; CON 6.3±1.1; Grip: EXP 2.5±2.4; CON 1.0±0.5, p’s > 0.05).

Conclusions: Use of a sham-control group allowed us to differentiate effects of rTMS when used to augment FTP. As hypothesized, high-frequency rTMS applied to the ipsilesional hemisphere did augment the effects of FTP. We interpret these results with caution as this differential effect was not observed across all outcome measures.

Clinical Relevance: We provide initial evidence that ipsilesional high-frequency rTMS may serve to augment FTP of the paretic UE to improve functional ability. However, differential improvements in measures of impairments were not observed in this cohort of chronic post-stroke participants. Continued investigations of rTMS as a potential rehabilitation modality are needed to determine its clinical utility for individuals post-stroke.

Rose, Dorian Kay, PhD, PT; Patten, Carolynn , PhD, PT. Does Excitatory rTMS Augment Functional Task Practice to Improve Arm Recovery Post-Stroke?. Poster Presentation. IV STEP Conference, American Physical Therapy Association, Columbus, OH, July 17, 2016. Online.