BME PhD Preliminary Exam Announcement for Awadh M. Alhawwash (K. Yoshida and H. Lee, co-advisors) Everyone is invited to attend the public presentation beginning at 1:00 PM. Title: Exploring Sinusoidal Low Frequency Alternating Currents (LFAC) as a New Modality for Functional Electrical Stimulation Date: May 2, 2023 Time: 1:00 PM Location: IUPUI SL 220A or Zoom -https://purdue-edu.zoom.us/j/91256810994?pwd=ai9qR3EvWndIRW9paEx3eE4yM2RjZz0... * Committee members: Dr. Ken Yoshida (Co-advisor) Dr. Hyowon Hugh Lee (Co-advisor) Dr. Edward J. Berbari Dr. Matthew P. Ward Abstract: Functional Electrical Stimulation (FES) is a promising rehabilitative technology that provides hope for restoring functional movements in patients suffering from paralysis caused by spinal cord injury, stroke, or traumatic brain injury. However, the clinical effectiveness of FES is limited by the simultaneous occurrence of muscle fatigue and excessive metabolic cost resulting from the reversed order of muscle fiber recruitment of conventional pulse stimulation. In this project, we propose the use of sinusoidal low frequency alternating current (LFAC) stimulation as a novel motor nerve stimulation method. Our pilot study in a rabbit model showed that LFAC stimulation induced long-lasting non-fatiguing muscle contractions, necessitating further investigation. This research aims to explore and comprehensively analyze the muscle contractions elicited by LFAC stimulation using cuff electrodes. Electrodes are placed on the sciatic nerve of anesthetized rats to evoke motor activity using pulse and LFAC stimulation. The order of motor unit recruitment and rate of muscle fatigue are compared for LFAC and pulse stimulation. The initial results indicate that the muscle is activated by LFAC stimulation. The EMG activity was phase-locked to the sinusoidal cycle but exhibited two distinct phenotypes: burst and unitary. The LFAC activation threshold was frequency-dependent and influenced by the cuff electrode geometry. The soleus muscle, mediated by smaller caliber alpha motor neurons, generally had a lower LFAC activation threshold than the lateral gastrocnemius, mediated by larger caliber alpha motor neurons. This finding suggests a normal "physiological" recruitment order is obtained using LFAC stimulation. A comparison of fatigue rate between pulse and LFAC stimulation is pending, but initial indications are that LFAC-based stimulation has greater fatigue resistance but greater force production variability. Systematic characterization of LFAC-based motor nerve stimulation aims to provide empirical evidence to identify the mechanism and locus of action of LFAC stimulation. This will establish a foundation for LFAC to be developed as a new modality in the field of neuromodulation, with the potential to overcome limitations and enhance the effectiveness and usability of FES technology. *Zoom meeting additional information: Time: May 2, 2023 01:00 PM Eastern Time (US and Canada) Meeting ID: 912 5681 0994 Passcode: 860596 One tap mobile +13092053325,,91256810994#,,,,*860596# US +13126266799,,91256810994#,,,,*860596# US (Chicago) Dial by your location +1 309 205 3325 US +1 312 626 6799 US (Chicago) +1 646 558 8656 US (New York) +1 646 931 3860 US +1 301 715 8592 US (Washington DC) +1 305 224 1968 US +1 360 209 5623 US +1 386 347 5053 US +1 507 473 4847 US +1 564 217 2000 US +1 669 444 9171 US +1 669 900 6833 US (San Jose) +1 689 278 1000 US +1 719 359 4580 US +1 253 205 0468 US +1 253 215 8782 US (Tacoma) +1 346 248 7799 US (Houston) Meeting ID: 912 5681 0994 Passcode: 860596 Find your local number: https://purdue-edu.zoom.us/u/acjXQSfaK Join by SIP 91256810994@zoomcrc.com<mailto:91256810994@zoomcrc.com> Join by H.323 162.255.37.11 (US West) 162.255.36.11 (US East) Meeting ID: 912 5681 0994 Passcode: 860596