About this trial
The purpose of this study is to 1) examine the differences in walking function and movement patterns between individuals with diabetic peripheral neuropathy and healthy adults with no known conditions; 2) examine if receiving feedback on walking form will help change walking patterns; and 3) examine the feasibility, safety, and preliminary effects of walking training with feedback on walking function in individuals with diabetic peripheral neuropathy.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Age 45+ years
Able to walk 10-meters independently without an assistive device
Sufficient cardiovascular and musculoskeletal health to walk on a treadmill for 1-minute at self-selected speed
Diagnosis of DM
Disqualifiers
History of neurologic disease
History of orthopaedic disease affecting the lower extremities
History of injury or pain affecting the lower extremity or walking function within the past 6 months
History of amputation
Trial design
Crossover
Treatments tested in this trial
Clinical Evaluation
Other interventionA clinical evaluation occurs at the first study session. The clinical evaluation assesses walking function and mobility, lower extremity, sensation, health-related quality of life (HRQoL) and foot function. Session 2 will be a dynamometer-based evaluation of passive ankle stiffness and 3-dimensional gait analysis to evaluate baseline biomechanics. During Session 3, real-time biofeedback conditions will be used to measure the immediate effects on walking function.
Evaluation of Passive Ankle Stiffness
Other interventionParticipants will be seated in a dynamometer with their trunk and thigh stabilized to the dynamometer chair, ankle joint aligned with the rotational axis of the dynamometer, and foot stabilized to the foot plate. EMG activity will be recorded from lower limb muscles (gastrocnemius, soleus, tibialis anterior) during all isolated contractions. Participants will first perform three maximum voluntary isometric contractions (MVIC) while seated in a dynamometer. Participants will then perform three isokinetic dorsiflexion tasks while using electromyographic biofeedback at a prescribed level of 50% MVIC soleus activation. The slope of the linear best fit line from the ankle moment vs. angle plot will yield total ankle joint stiffness (i.e., active + passive) at a fixed activation. In three additional trials, the dynamometer will move the ankle joint through the same motion without active subject resistance and the same analytical procedures will derive passive ankle joint stiffness.
Gait Biomechanics
Other interventionThree-dimensional gait analysis is performed as participants walk at a self-selected speed on an instrumented treadmill. Reflective markers are attached to lower extremity segments. Elastic bands are wrapped around the thighs, calves, and pelvis to which small, thermoplastic shells containing reflective markers are attached. Additional markers are taped to the participant's shoes and on the upper back, shoulder, hip, knee, and ankle joints with adhesive skin tape. Marker data is collected using a 7-camera motion analysis system (Vicon Inc., USA). Vicon motion analysis cameras will collect the location of the retroreflective markers in Vicon Nexus software.
Gait Biofeedback
Other interventionAudio-visual biofeedback will be provided using a screen placed in front of the treadmill and a speaker. For plantar pressure biofeedback, a visual display of a foot with a colored heat map will represent the current plantar pressure, in addition to bar graphs representing real-time movement of plantar pressure in specific areas of the foot. A target will be provided using the heat map colors of red and target line on the bar graph. For propulsion biofeedback, a visual display with a marker will represent the current propulsion (peak AGRF) and a target provided to modulate propulsion. The plantar pressure and AGRF measurements from the participant's baseline walking trials will be used to determine customized biofeedback targets.
Plantar Pressure Biofeedback Gait Training
Other interventionParticipants will complete a 3-dimensional gait evaluation prior to training, after a 6-minute control bout without biofeedback, and following three 6-minute biofeedback training bouts (total 18-minutes). Individualized biofeedback targets will be calculated from each participant's immediate biofeedback session to best minimize plantar pressure whilst maintaining or enhancing propulsion. Audio-visual biofeedback is provided using a screen placed in front of the treadmill and a speaker. For plantar pressure biofeedback, a visual display of a foot with a colored heat map represents the current plantar pressure, in addition to bar graphs representing real-time movement of plantar pressure in specific areas of the foot. A target is provided using the heat map colors of red and target line on the bar graph. Participants are informed that the target is a measurement of the pressure under their foot, and their goal is to decrease pressure to achieve their target.
Propulsion Biofeedback Gait Training
Other interventionParticipants will complete a 3-dimensional gait evaluation prior to training, after a 6-minute control bout without biofeedback, and following three 6-minute biofeedback training bouts (total 18-minutes). Individualized biofeedback targets will be calculated from each participant's immediate biofeedback session to best minimize plantar pressure whilst maintaining or enhancing propulsion. Audio-visual biofeedback is provided using a screen placed in front of the treadmill and a speaker. For propulsion biofeedback, a visual display with a marker represents the current propulsion (peak AGRF) and a target provided to modulate propulsion. Participants are informed that the marker is a measurement of how hard they are pushing the ground backward, and their goal is to push-off more to achieve their target.
Treatment groups
Trial outcomes
Primary outcomes
Biomechanical plantar pressure
Plantar pressure is calculated in kilopascals (kPa) using a force sensor placed between the participant's foot and insole of their shoe. The peak plantar pressure in regions of interest (forefoot) will be calculated.
Biomechanical Propulsion
Propulsion is calculated as the maximum anteriorly directed ground reaction force during the stance phase of gait using the instrumented (force plate) treadmill.
Biomechanical modulation of ankle stiffness
Participants will walk for 3 minutes on a treadmill at their self-selected speed to enable stabilization of movement patterns, warmup, and preconditioning of lower extremity muscles prior to dynamometer tasks. Participants will then be seated in a dynamometer with their trunk and thigh stabilized to the dynamometer chair, ankle joint aligned with the rotational axis of the dynamometer, and foot stabilized to the foot plate. Electromyography (EMG) activity will be recorded from lower limb muscles during all isolated contractions. Participants will first perform three maximum voluntary isometric contractions (MVIC) while seated in a dynamometer. Participants will then perform three isokinetic dorsiflexion tasks while using electromyographic biofeedback at a prescribed level of 50% MVIC soleus activation. The slope of the linear best fit line from the ankle moment vs. angle plot will yield total ankle joint stiffness at a fixed activation.
Secondary outcomes
Changes induced by biofeedback in plantar pressure
Plantar pressure measurements will be recorded using insoles placed between the surface of the foot and the insole of the participant's shoe. Marker data, GRFs, and plantar pressure data will be synchronized. Regression analysis will be used to examine plantar pressure during gait by study group.
Changes induced by biofeedback in propulsion
Ground reaction force (GRF) data will be collected independently from each leg using a split-belt treadmill instrumented with two 6-degree of freedom force platforms. The antero-posterior GRFs (AGRF) will be used to compute propulsion. Regression analysis will be used to examine propulsion during gait by study group.
Changes induced by biofeedback in biomechanics during gait
Lower extremity kinetics and kinematics will be measured using a three-dimensional motion analysis system and split-belt instrumented treadmill. Kinetics and kinematics of the ankle, knee, and hip will be analyzed during gait.
Sponsors and contacts
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Florida Institute for Human and Machine Cognition
Lead sponsor
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Collaborator