Research Report
Population: Adult
Edelle Carmen Field-Fote, PT, PhD, FAPTA, Director of Spinal Cord Injury Research, Crawford Research Institute, Shepherd Center edelle_field-fote@shepherd.org
Joyce Gomes-Osman, PT, PhD, Assistant Professor, Department of Physical Therapy, University of Miami Miller School of Medicine j.gomes@miami.edu
Kathryn Roach, PT, PhD, Professor, Department of Physical Therapy, University of Miami Miller School of Medicine keroach@miami.edu
Jacqueline Tibbett, BS, PhD student, Department of Physiology & Biophysics, University of Miami Miller School of Medicine j.tibbett@med.miami.edu
Katherine Brisson, SPT, DPT student, Department of Physical Therapy, University of Delaware kat.rosebrisson@gmail.com
Keywords: Prevention
Purpose/Hypothesis: In persons with tetraplegia small improvements in hand function can make a meaningful difference for function. Evidence suggests that somatosensory stimulation is associated with increased cortical excitability and improved hand function. In persons with tetraplegia, increased corticomotor excitability may result in a larger amount of the cortical signal associated with voluntary drive being propagated down spared corticospinal pathways. We hypothesized that in subjects with chronic tetraplegia, peripheral nerve somatosensory stimulation plus functional task practice training (PNSS+FTP) would be associated with greater improvements compared to PNSS alone, or conventional resistance training (CRT; universal gym). We also hypothesized that the changes in hand function would be reflected in changes in cortical excitability.
Subjects: Participants were 49 individuals with a chronic (> 1 year) tetraplegia due to spinal cord injury with neurological of level C7 or above.
Materials/Methods: This study was a single-blind, randomized clinical trial. Participants were randomized to 1 of 3 groups, including: PNSS+FTP, PNSS alone, or CRT. Participants were trained 5 days/week for 4 weeks. Pinch and grip forces were measured via dynamometer. Eleven items from the Chedoke Arm and Hand Activity Inventory (scored based on 7 levels of assistance) were used to assess hand function; 4 Chedoke items primarily involved pinch, 7 involved grip. Motor evoked potentials (MEPs) acquired with transcranial magnetic stimulation (TMS) were used to assess cortical excitability.
Results: Of the 49 subjects enrolled, useable pre-and posttest data was obtained from 37 subjects (PNSS+FTP n=14, PNSS n=13, CRT n=10). PNSS+FTP was associated with the greatest change in pinch force of the weaker (1.5±2.8 lbs) and stronger hand (1.9±3.7 lbs), and grip force of the stronger hand (2.5±7.4 lbs). On average, PNSS+FTP improved 28.6% of the Chedoke pinch items compared to 20% and 15% for the PNSS and CRT groups. In contrast, CRT improved 31.4% of the Chedoke grip items compared to 24.5% and 22.9% for PNSS+FTP and PNSS. In the PNSS+FTP and CRT groups changes were observed in MEP threshold and area under the recruitment curve.
Conclusions: PNSS+FTP was associated with the largest increases in pinch and grip strength, and ability to perform functional pinch activities. CRT was associated with the largest increases in ability to perform functional grip activities. Changes in measures of cortical excitability accompanied changes in motor performance.
Clinical Relevance: Training-related changes in functional hand use are observed years after tetraplegia. The use of PNSS is a clinically accessible approach to augmenting the effects of FTP, and this combined intervention appears to be valuable for improving hand function and increasing pinch and grip force production.
Funding Source: This study was supported by NIH R01HD053854 (EFF).
Citation:
Field-Fote, Edelle Carmen, PT, PhD, FAPTA; Gomes-Osman, Joyce , PT, PhD; Roach, Kathryn E, PT, PhD; Tibbett, Jacqueline , BS; Brisson, Katherine , SPT. Functional task practice augmented with somatosensory stimulation is superior to resistance training for improving hand strength and function in persons with tetraplegia.. Poster Presentation. IV STEP Conference, American Physical Therapy Association, Columbus, OH, July 17, 2016. Online. https://u.osu.edu/ivstep/poster/abstracts/037_field-fote-et-al/