Abstracts

  • Abstract deadline is February 15, 2018.
  • Abstracts should conform to the requirements used by the Society for Neuroscience (~300 words), as indicated in the example shown below.
  • Abstracts must be submitted by e-mail to Roger Enoka (enoka@colorado.edu). Please place “IMS abstract” in the subject line.
  • Each abstract will be evaluated by the Organizing Committee based on the relevance of its content to the topics that will be discussed at the Conference.
  • Authors will be informed of the decision no later than March 15, 2018.
  • Most accepted abstracts will be assigned to poster sessions distributed throughout the Conference.

Multielectrode stimulation to reduce fatigue associated with functional electrical stimulation

*A. J. BUCKMIRE1, T. J. ARAKERI2, J. P. REINHARD3, A. J. FUGLEVAND1,2,4

1-Neuroscience, 2-Biomed Engineering, 3-Anesthesiology, 4-Physiology, Univ. of Arizona, Tucson, AZ

Restoration of motor function in paralyzed limbs using functional electrical stimulation (FES) has not gained widespread use due, in part, to rapid fatigue associated with artificial stimulation. Typically, single intramuscular electrodes are used to activate muscles with FES. However, due to the highly distributed branching of intramuscular motor axons, a single electrode may be insufficient to activate the entire nerve array supplying a muscle. Therefore, stimulating with multiple, spatially distributed electrodes might enable access to a larger volume of muscle fibers. This, in turn, should facilitate load- sharing among muscle fibers, reducing fatigue. Accordingly, the aim of this study was to compare fatigue responses associated with contractions elicited by electrical stimulation delivered by a single intramuscular electrode to that involving multiple electrodes. Four healthy human subjects each participated in 4 experimental sessions. In each session, the endurance time associated with a sustained ankle dorsiflexion at 20% of the maximum voluntary force was measured. In different sessions, force was evoked in response to feedback-controlled electrical stimulation of the tibialis anterior using a single intramuscular electrode, multiple intramuscular electrodes, or a single intraneural electrode inserted into the peroneal nerve. In addition, in one session, subjects performed a sustained voluntary contraction at the target force. In all sessions involving electrical stimulation, a localized nerve block was applied to the peroneal nerve proximal to the knee in order to alleviate discomfort and activation of reflex pathways associated with strong electrical stimulation. Electrical stimulation (25 Hz) involved feedback control of stimulus pulse amplitude until the evoked force could no longer be maintained within 5% of the target force. Endurance time was substantially less for that involving single electrode stimulation (69 s) compared to that involving multiple electrodes (165 s), intraneural stimulation (728 s), or voluntary contraction (941 s). Thus, it appears that a marked reduction in FES-related fatigue could be achieved using stimulation strategies.

Grant/Other Support: NIH Grant NS096064