The project is designed to develop and test Pressure Alternating Shoes (PAS), which will periodically off-load certain regions of the foot in order to prevent foot ulcers. An automated dual layer insole compromised of an active pressurized actuator array in combination with a passive compliant layer on top of each actuator to modulate and distribute the plantar surface pressure as desired will be tested. This device will allow us to simultaneously load and offload select areas of the foot using the active layer by inflating and deflating individual actuators using pressurized air. After offloading, the remaining load will be distributed to other areas with inflated actuators. Automatic modulation will be provided through programmable control hardware which will cyclically relieve mechanical loading based on a prescribed duration and frequency.
The two-tier human subjects study will be conducted to assess the biomechanical characteristics of PAS. In the first tier, we will test PAS in healthy subjects and in the second tier, we will test PAS in Diabetic Neuropathy patients (DN). Subjects will walk on a treadmill in their usual daily shoes for 5 minutes, then with standard diabetic shoes with the PAS insoles for 5 minutes. Subjects will wear body worn sensors that assess position of the body. Subjects will have the temperature of their feet measured via a special camera after walking. Subjects will rest for 30 minute washout period and have the blood flow in the soles of the feet measured via a special camera. 1 healthy subject will undergo MRI of the foot and ankle.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
21
test pressure alternating shoes
University of Texas Southwestern Medical Center
Dallas, Texas, United States
Maximum Average Pressure at Baseline With Pressure Alternating Shoes, Right Foot (Before Any Cells Were Offloaded)
Maximum Average pressure values in the plantar regions before offloading during walking. The insole consists of seven air cells that align with specific regions: the big toe (cell 1), the area spanning from the second toe to the fifth toe (cell 2), metatarsal heads (cells 3 and 4), the midfoot (cells 5 and 6), and the heel (cell 7). Measurements were only obtained from the right foot.
Time frame: Before any cells were offloaded (First 40-seconds of the walk)
Maximum Average Pressure at After Offloading - Diabetic Footwear Equipped With PAS Device
Maximum Average pressure values in the plantar regions after offloading cells during walking. The insole consists of seven air cells that align with specific regions: the big toe (cell 1), the area spanning from the second toe to the fifth toe (cell 2), metatarsal heads (cells 3 and 4), the midfoot (cells 5 and 6), and the heel (cell 7). Measurements were only obtained from the right foot. The results reported represent results for footwear with PAS device.
Time frame: After offloading (approx. 41- 200 seconds walk)
Peak Interface Pressure at Baseline (Before Offloading) - Diabetic Footwear Equipped With PAS Device
Peak Interface Pressure values in the plantar regions before offloading during walking. The insole consists of seven air cells that align with specific regions: the big toe (cell 1), the area spanning from the second toe to the fifth toe (cell 2), metatarsal heads (cells 3 and 4), the midfoot (cells 5 and 6), and the heel (cell 7). Measurements were only obtained from the right foot. The results reported represent results for footwear with PAS device.
Time frame: Baseline (First 40-seconds of the walk)
Peak Interface Pressure at After Offloading - Diabetic Footwear Equipped With PAS Device
Peak Interface Pressure values in the plantar regions after offloading during walking. The insole consists of seven air cells that align with specific regions: the big toe (cell 1), the area spanning from the second toe to the fifth toe (cell 2), metatarsal heads (cells 3 and 4), the midfoot (cells 5 and 6), and the heel (cell 7). Measurements were only obtained from the right foot. The results reported represent results for footwear with PAS device.
Time frame: After offloading (approx. 41- 200 seconds walk)
Max Average Pressure Change Among All Participants - Diabetic Footwear Equipped With PAS Device
Percentage change due to offloading for each participant is measured by dividing the pressure difference between the after offloading and before offloading values divided by the before offloading value. Measurements were only obtained from the right foot. The results reported represent results for footwear with PAS device.
Time frame: Baseline (first 40-second walk), 201 seconds after the intervention ended
Peak Pressure Change Among All Participants - Diabetic Footwear Equipped With PAS Device
Peak pressure change due to offloading for each participant is measured by dividing the pressure difference between the peak after offloading and peak before offloading values divided by the peak before offloading value. Measurements were only obtained from the right foot. The results reported represent results for footwear with PAS device.
Time frame: Baseline (first 40-second walk), 201 seconds after the intervention ended
Plantar Skin Temperature at Baseline, Right Foot
Plantar skin temperature measured by a noncontact thermal imaging camera (\*Celcius) before the intervention and without footwear
Time frame: Baseline before the intervention (30 minutes after start of visit 1)
Plantar Skin Temperature Post Intervention, Right Foot
Plantar skin temperature measured by a noncontact thermal imaging camera (\*Celcius) post intervention, without footwear
Time frame: Post intervention (215 seconds)
Tissue Oxygenation (Oxygen Saturation) - for Plantar Lateral Foot
Plantar foot tissue oxygenation (Oxygen saturation) is measured by noncontact hyperspectral imaging camera (StO2). Only the right foot was analyzed and without footwear.
Time frame: Baseline (30 minutes after start of visit 1)
Tissue Oxygenation (Oxyhemoglobin and Deoxyhemoglobin ) - for Plantar Lateral Foot
Plantar foot tissue oxygenation (Oxyhemoglobin and Deoxyhemoglobin) is measured by noncontact hyperspectral imaging (HSI) camera. Only the right foot was analyzed and without footwear. The accepted measure of oxyhemoglobin and deoxyhemoglobin is arbitrary units (AU). NIR spectrum light passes through skin and is reflected off the blood supplying the tissue. Wavelength dependent light absorption of hemoglobin differs if it is carrying oxygen or not, therefore detecting oxygenated and deoxygenated blood. This was derived from Beer-Lambert Law but would need to be verified by the manufacturer. There is no researcher drawn calculation as the device provides the arbitrary unit based on the reflectance detected back to the imaging device. No reference values or any standardization available but one would infer higher oxyhemoglobin level indicates better oxygenation and thus a higher deoxyhemoglobin would be indicative of poor oxygenation.
Time frame: Baseline (30 minutes after start of visit 1)
Tissue Oxygenation (Oxygen Saturation) - for Plantar Medial Foot
Plantar Medial foot tissue oxygenation (Oxygen saturation) is measured by noncontact hyperspectral imaging camera (StO2). Only the right foot was analyzed and without footwear.
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Time frame: Baseline (30 minutes after start of visit 1)
Tissue Oxygenation (Oxyhemoglobin and Deoxyhemoglobin) - for Plantar Medial Foot
Plantar medial foot tissue oxygenation (Oxyhemoglobin and Deoxyhemoglobin) is measured by noncontact hyperspectral imaging (HSI) camera. Only the right foot was analyzed. Only the right foot was analyzed and without footwear. The accepted measure of oxyhemoglobin and deoxyhemoglobin is arbitrary units (AU). NIR spectrum light passes through skin and is reflected off the blood supplying the tissue. Wavelength dependent light absorption of hemoglobin differs if it is carrying oxygen or not, therefore detecting oxygenated and deoxygenated blood. This was derived from Beer-Lambert Law but would need to be verified by the manufacturer. There is no researcher drawn calculation as the device provides the arbitrary unit based on the reflectance detected back to the imaging device. No reference values or any standardization available but one would infer higher oxyhemoglobin level indicates better oxygenation and thus a higher deoxyhemoglobin would be indicative of poor oxygenation.
Time frame: Baseline (30 minutes after start of visit 1)
Tissue Oxygenation (Oxygen Saturation) - for Plantar Lateral Foot
Plantar foot tissue oxygenation (Oxygen saturation) is measured by noncontact hyperspectral imaging camera (StO2). Only the right foot was analyzed and without footwear.
Time frame: Post Gait (approx. 2015 seconds post intervention)
Tissue Oxygenation (Oxyhemoglobin and Deoxyhemoglobin ) - for Plantar Lateral Foot
Plantar foot tissue oxygenation (Oxyhemoglobin and Deoxyhemoglobin) is measured by noncontact hyperspectral imaging (HSI) camera. Only the right foot was analyzed and without footwear. The accepted measure of oxyhemoglobin and deoxyhemoglobin is arbitrary units (AU). NIR spectrum light passes through skin and is reflected off the blood supplying the tissue. Wavelength dependent light absorption of hemoglobin differs if it is carrying oxygen or not, therefore detecting oxygenated and deoxygenated blood. This was derived from Beer-Lambert Law but would need to be verified by the manufacturer. There is no researcher drawn calculation as the device provides the arbitrary unit based on the reflectance detected back to the imaging device. No reference values or any standardization available but one would infer higher oxyhemoglobin level indicates better oxygenation and thus a higher deoxyhemoglobin would be indicative of poor oxygenation.
Time frame: Post Gait (approx. 2015 seconds post intervention)
Tissue Oxygenation (Oxygen Saturation) - for Plantar Medial Foot
Plantar Medial foot tissue oxygenation (Oxygen saturation) is measured by noncontact hyperspectral imaging camera (StO2). Only the right foot was analyzed and without footwear.
Time frame: Post Gait (approx. 2015 seconds post intervention)
Tissue Oxygenation (Oxyhemoglobin and Deoxyhemoglobin) - for Plantar Medial Foot
Plantar medial foot tissue oxygenation (Oxyhemoglobin and Deoxyhemoglobin) is measured by noncontact hyperspectral imaging (HSI) camera. Only the right foot was analyzed and without footwear. The accepted measure of oxyhemoglobin and deoxyhemoglobin is arbitrary units (AU). NIR spectrum light passes through skin and is reflected off the blood supplying the tissue. Wavelength dependent light absorption of hemoglobin differs if it is carrying oxygen or not, therefore detecting oxygenated and deoxygenated blood. This was derived from Beer-Lambert Law but would need to be verified by the manufacturer. There is no researcher drawn calculation as the device provides the arbitrary unit based on the reflectance detected back to the imaging device. No reference values or any standardization available but one would infer higher oxyhemoglobin level indicates better oxygenation and thus a higher deoxyhemoglobin would be indicative of poor oxygenation.
Time frame: Post Gait (approx. 2015 seconds post intervention)
Balance
Positional sense measured by body-worn sensors (cm)
Time frame: Baseline