Detecting Change in Muscle Parameters, Pain, and Function With NMES for TTA

This study investigates the efficacy of a home-based Neuromuscular Electrical Stimulation (NMES) intervention in improving muscle parameters, reducing pain, and enhancing gait biomechanics in individuals with unilateral transtibial amputation (TTA). Muscle atrophy and sarcopenia, common in individuals with amputations, result in reduced muscle strength, volume, and functional impairments. The NMES intervention aims to counter these deficits by promoting muscle hypertrophy and improving residual limb muscle quality.

Ultrasound (US) imaging, a safe and non-invasive technique, will be used to assess muscle composition and quality, focusing on muscle thickness (MT), cross-sectional area (CSA), and muscle fat infiltration (MFI) of key muscle groups, including the vastus medialis oblique (VMO), tibialis anterior (TA), and gastrocnemius (GM) muscles. Baseline measures will be compared to post-NMES intervention data to evaluate changes in muscle parameters.

Participants will undergo an 8-week NMES program using a portable device. Electrode placement and settings will be customized to target specific muscle groups for optimal stimulation and contraction. Anthropometric measurements, gait analysis, and self-reported pain levels will be collected at baseline, midpoint, and post-intervention. The study will utilize US imaging to validate changes in muscle composition and quality and examine improvements in gait parameters such as stride length, velocity, and step symmetry using the GAITRite® system.

This project is a critical step in addressing the lack of standardized rehabilitation protocols for individuals with TTA. By leveraging NMES and US imaging, the study aims to develop a cost-effective, accessible intervention that enhances prosthetic fit, stabilizes limb volume, and improves mobility. The findings will contribute to refining rehabilitation strategies and improving the quality of life for individuals with limb loss.

Inclusion criteria

• 18 years or older
• Have a unilateral transtibial amputation
• Have normal sound limb range of motion and function
• Have a minimum of 4" length limb from tibial tubercle to end of residuum to allow room for NMES pads
• Report current pain at a level 3 or higher on a Visual Analog Scale (VAS)
• Pass a monofilament test on the residual limb in 7 out of 10 areas to ensure adequate sensation for NMES stimulation
• Have a body mass index (BMI) of 35 kg/cm2 or less as NMES works more effectively on lower BMI

Exclusion criteria

• Have used electrical stimulation on the residual limb in the past six months
• Have been diagnosed as a severe diabetic or self-report insensate skin
• Have the presence of open wounds/ulcers on the residual limb
• Have experienced a cerebrovascular accident (stroke) or nerve injury to a lower limb
• Wear a pacemaker or implanted cardiac defibrillator