PNS to Improve Vascular Function and Limb Health in Veterans

Establishing a sensitive, scalable physiological test for neurovascular reflex integrity and investigating whether targeted peripheral neural stimulation can enhance perfusion and vasodilatory responsiveness.

Inclusion Criteria: Inclusion Criteria - All Participants: * English-speaking Inclusion Criteria - DPN Participants: * Confirmed diagnosis of type 1 or type 2 diabetes mellitus for at least 5 years * Clinical signs and/or symptoms consistent with diabetic peripheral neuropathy Or confirmation of neuropathy via physical exam Inclusion Criteria - Lower Limb Amputees: * Unilateral transtibial or transfemoral amputation * Medically stable for at least 3 months * For the designated subset of the limb-loss cohort (n = 6): implanted with C-FINEs on the sciatic and/or tibial nerves Exclusion Criteria: Exclusion Criteria - All Participants: * Severe neurological disorders impairing ambulation * Visual or hearing impairments interfering with study participation * Cardiovascular or respiratory conditions posing risk during participation * Cognitive or psychiatric conditions compromising informed consent * Participation in other clinical trials interfering with outcomes * Pregnancy * History of photosensitivity or known sensitivity to laser light Additional Exclusion Criteria - Amputees: * Active skin breakdown or infection at residual limb * Significant phantom or residual limb pain interfering with study procedures * Bilateral lower-limb amputation