Interleaved neuromuscular electrical stimulation after spinal cord injury

• Published in: Muscle & nerve 2017-11, Vol.56 (5), p.989-993
• Main Authors: Bergquist, Austin J., Wiest, Matheus J., Okuma, Yoshino, Collins, David F.
• Format: Article
• Language: English
• Subjects: Adult; Biophysics; Delivery contracts; Electric Stimulation - methods; electrical stimulation; Electrical stimuli; Electromyography; Fatigue; Fatigue - etiology; Fatigue - therapy; Female; Flexors; Humans; H‐reflex; Male; Middle Aged; Motor units; Muscle Contraction - physiology; M‐wave; Neuromuscular electrical stimulation; Neuromuscular Junction - physiology; Paralysis; Plantar flexion; recruitment; Recruitment, Neurophysiological - physiology; Spinal cord injuries; Spinal Cord Injuries - complications; Spinal Cord Injuries - therapy; Stimulation; Torque; Treatment Outcome; Waves
• ISSN: 0148-639X; 1097-4598
• DOI: 10.1002/mus.25634

ABSTRACT Introduction Neuromuscular electrical stimulation (NMES) over a muscle belly (mNMES) recruits superficial motor units (MUs) preferentially, whereas NMES over a nerve trunk (nNMES) recruits MUs evenly throughout the muscle. We performed tests to determine whether “interleaving” pulses between the mNMES and nNMES sites (iNMES) reduces the fatigability of contractions for people experiencing paralysis because of chronic spinal cord injury. Methods Plantar flexion torque and soleus electromyography (M‐waves) were recorded from 8 participants. A fatigue protocol (75 contractions; 2 s on/2 s off for 5 min) was delivered by iNMES. The results were compared with previously published data collected with mNMES and nNMES in the same 8 participants. Results Torque declined ∼40% more during mNMES than during nNMES or iNMES. M‐waves declined during mNMES but not during nNMES or iNMES. Discussion To reduce fatigability of electrically evoked contractions of paralyzed plantar flexors, iNMES is equivalent to nNMES, and both are superior to mNMES. Muscle Nerve 56: 989–993, 2017