The Effect of Cutaneous Electrical Stimulation on Hypertonia in Chronic Hemiparetic Stroke
Session Number
Project ID: MEDH 12
Advisor(s)
Dr. Julius P.A. Dewald; Northwestern University, Dept. of Physical Therapy and Human Movement Sciences / Dept. of Biomedical Engineering
Dr. Hendrik A. DewaldNorthwestern University, Dept. of Physical Therapy and Human Movement Sciences / Case Western Reserve University, Dept. of Biomedical Engineering
Dr. M.Hongchul Sohn; Northwestern University, Dept. of Biomedical Engineering
Discipline
Medical and Health Sciences
Start Date
19-4-2023 11:25 AM
End Date
19-4-2023 11:50 AM
Abstract
Cumulating evidence suggests that upregulation of corticoreticulospinal pathways following a stroke-induced loss of corticobulbar projections drives spinal motoneuro hyper-excitability. In turn, individuals with stroke experience increased muscl tone (i.e., hypertonia) and associated hyperactive stretch reflexes (i.e., spasticity). It has been shown that applying low-intensity (sub-motor-threshold) electrical stimulation to the skin reduces spasticity in individuals with hemiparetic stroke, as quantified by reflex torque responses at the elbow (Dewald et al., 1996). The purpose of this study was to determine whether cutaneous electrical stimulation can reduce hypertonia, as measured from background muscle activity. To this end, we measured hypertonia while the participant (N=1) was sitting relaxed (‘Baseline’, 10 minutes) with the arm fully supported (shoulder abduction 80°, shoulder flexion 0°; elbow extension 110°), before and after applying low-intensity stimulation to skin over the biceps muscle (20Hz, 0.1ms pulse duration, for 10 minutes). As a control, a sham trial was included (10 minutes, stimulation amplitude reduced to 0 within the first 1 minute) . The procedure was repeated on two separate days, with the order of the sham and stimulation trials switched. Hypertonia expressed in biceps muscle was quantified using a time-based surface electromyography (EMG) metric previously developed to capture the duration of active state of muscle relative to true relaxation (Sohn et al., 2022). Our preliminary results showed that hypertonia was indeed reduced after cutaneous electrical stimulation compared to following the sham trial in both days (p
The Effect of Cutaneous Electrical Stimulation on Hypertonia in Chronic Hemiparetic Stroke
Cumulating evidence suggests that upregulation of corticoreticulospinal pathways following a stroke-induced loss of corticobulbar projections drives spinal motoneuro hyper-excitability. In turn, individuals with stroke experience increased muscl tone (i.e., hypertonia) and associated hyperactive stretch reflexes (i.e., spasticity). It has been shown that applying low-intensity (sub-motor-threshold) electrical stimulation to the skin reduces spasticity in individuals with hemiparetic stroke, as quantified by reflex torque responses at the elbow (Dewald et al., 1996). The purpose of this study was to determine whether cutaneous electrical stimulation can reduce hypertonia, as measured from background muscle activity. To this end, we measured hypertonia while the participant (N=1) was sitting relaxed (‘Baseline’, 10 minutes) with the arm fully supported (shoulder abduction 80°, shoulder flexion 0°; elbow extension 110°), before and after applying low-intensity stimulation to skin over the biceps muscle (20Hz, 0.1ms pulse duration, for 10 minutes). As a control, a sham trial was included (10 minutes, stimulation amplitude reduced to 0 within the first 1 minute) . The procedure was repeated on two separate days, with the order of the sham and stimulation trials switched. Hypertonia expressed in biceps muscle was quantified using a time-based surface electromyography (EMG) metric previously developed to capture the duration of active state of muscle relative to true relaxation (Sohn et al., 2022). Our preliminary results showed that hypertonia was indeed reduced after cutaneous electrical stimulation compared to following the sham trial in both days (p