Fahad Arif
Research Mentor: Chandramouli Krishnan
Mentor Department: Physical Medicine & Rehabilitation, Medicine
Author(s): Fahad Arif, Jeffrey Lee, Luxiao Lu, Samuel McDonough, Thomas Augenstein, Chandramouli Krishnan
Session: Session 3 (11:00 AM – 11:50 AM)
Presentation Type: Poster 85
Abstract
Neuromuscular stimulation (NMES) is the use of electrical stimulation to elicit muscle contractions and is often used with individuals with neurological injuries to either rehabilitate motor function or assist completion of functional activities (called functional electrical stimulation, or FES). Conventional NMES/FES systems involve a muscle stimulator unit that produces an electrical current pulse train between two transcutaneous electrodes placed on a single muscle or muscle group. However, these systems inhibit scaling NMES to stimulate multiple muscles, as they require one stimulator per muscle/muscle group. Tools exist that can split a single stimulator output across multiple electrode pairs, but these tools are passive and lack flexibility, digital integration, and real-time controllability. Here, we developed a system that can configure muscle stimulator current flow to multiple electrode pairs and be controlled in real time for use in rehabilitation and biomedical applications. The system consists of a microcontroller (Arduino MEGA) and a custom printed circuit board. The circuit board uses a parallel resistor network controlled by the microcontroller and optical MOSFETs to configure the resistance level across each electrode path. The microcontroller interfaces with an existing FES system that uses inertial measurement units to automatically trigger stimulation, and thus, the resistance level along each path can be controlled in real time. We performed benchtop validations of our system to show that the circuit distributed current across each path as expected, and that these current distributions led to meaningful changes in muscle contractions. We plan to validate our system in human subjects by showing that real time control of the system can lead to meaningful changes in joint biomechanics during gait. Once finalized, this design could serve as a foundation for novel electrical stimulation research and clinical rehabilitation.
