None listed
Conditions
Brief summary
Many people with diabetes develop nerve damage in their feet and lower legs that causes ongoing pain, often described as burning, stabbing or electric shock-like, which is frequently not well relieved by medication. This study is testing whether adding a simple flashing light, synchronised with the pulses of a TENS (Transcutaneous Electrical Nerve Stimulation) machine, changes people's experience of that pain compared with TENS on its own.
Interventions
Arm 1 (Control): TENS alone
Participants receive transcutaneous electrical nerve stimulation (TENS) delivered using a NeuroTrac® MyoPlus4 Pro Electrical Stimulation and Biofeedback Device (Verity Medical Ltd, United Kingdom), operated in TENS mode with a fixed stimulation protocol.
Materials: the NeuroTrac® MyoPlus4 Pro device, lead wires, and self-adhesive surface electrodes.
Stimulation parameters: biphasic, charge-balanced, rectangular pulses delivered at a fixed frequency of 50 Hz and a fixe
Arm 1 (Control): TENS alone Participants receive transcutaneous electrical nerve stimulation (TENS) delivered using a NeuroTrac® MyoPlus4 Pro Electrical Stimulation and Biofeedback Device (Verity Medical Ltd, United Kingdom), operated in TENS mode with a fixed stimulation protocol. Materials: the NeuroTrac® MyoPlus4 Pro device, lead wires, and self-adhesive surface electrodes. Stimulation parameters: biphasic, charge-balanced, rectangular pulses delivered at a fixed frequency of 50 Hz and a fixed pulse width of 350 microseconds. Amplitude is not fixed; it is individually titrated for each participant to a clearly perceptible, comfortable sensory level, below the pain threshold, and the value used is recorded for each participant. Procedure: participants are seated comfortably with their feet supported. Skin at the electrode sites is inspected and cleaned with an alcohol wipe. Self-adhesive surface electrodes are applied over standardised sites on the dorsal foot and around the ankle, positioned to preferentially activate the peroneal and tibial nerves. Stimulation intensity is increased gradually from zero to a level the participant describes as "strong but comfortable", below the pain threshold, and is not increased further once a stable comfortable level is reached. The selected settings are documented for each participant, and intensity may be reduced at any time at the participant's request. Dose and schedule: 20 minutes of active stimulation delivered in a single session as two 10-minute blocks separated by a 5-minute seated rest. Additional rest breaks may be requested at any time. The intervention is delivered once only, during a single supervised laboratory visit lasting approximately 2 hours in total. Mode of delivery: face-to-face, individually administered. Provider: trained research staff of the study team, under the supervision of the chief investigator, in a university laboratory. Location: The MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Westmead campus, NSW, Australia. Tailoring: stimulation amplitude is individually titrated to each participant's sensory threshold as described above. Waveform, frequency and pulse width are fixed and identical across participants and across both arms. Fidelity: a researcher remains in the room for the entire stimulation period, monitors participant comfort, and records the stimulation settings used, the duration of stimulation actually delivered, any pauses or dose reductions, and any adverse events on the case report form. Arm 2 (Experimental): TENS plus synchronised visual feedback Participants receive the identical TENS protocol described for Arm 1, including the same waveform, frequency, pulse width and amplitude titration procedure, with the addition of a synchronised visual feedback accessory. Materials: as for Arm 1, plus an external, battery-powered LED strip. Procedure: the LED accessory detects TENS pulses in the lead wires by inductive coupling and, via a microcontroller, triggers brief increases in LED brightness that coincide with each stimulation burst. The accessory does not modify the TENS device or alter the delivered current; it functions solely as a passive detector and visual indicator, and does not contact the participant's body. The LED strip is positioned so that it is easily visible to the participant at the location of the foot, without obstructing movement or causing glare. Dose, schedule, mode of delivery, provider, location, tailoring and fidelity monitoring are identical to Arm 1.
Sponsors
Western Sydney University
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Participants must meet all of the following: - Aged 18 years or older. - Established clinical diagnosis of type 1 or type 2 diabetes mellitus. - Pain affecting the foot and/or lower leg (distal to the knee) present for at least 3 months. - Pain characteristics consistent with painful diabetic peripheral neuropathy on screening, for example burning, stabbing, shooting or electric shock-like pain, tingling, hypersensitivity, or discomfort provoked by normally non-painful stimuli such as socks or bedsheets. - Clinical signs consistent with painful diabetic peripheral neuropathy, confirmed at the laboratory visit by non-invasive sensory testing, defined as abnormal findings on one or more of: vibration perception testing using a neurothesiometer, 10 g monofilament light touch testing at standard plantar sites, pinprick sensation testing using a Neurotip device. - Able to attend a single laboratory visit at Western Sydney University and complete a 24-hour telephone follow-up. - Able to sit comfortably for the duration of the stimulation session. Sufficient written and spoken English to provide informed consent and complete the study questionnaires. - Willing to wear surface electrodes on the feet and ankles.
Exclusion criteria
Participants will be excluded if any of the following apply: - Presence of an implanted electronic medical device, including cardiac pacemaker, implantable cardioverter-defibrillator, deep brain stimulator or spinal cord stimulator. - History of epilepsy or a seizure disorder. - Current pregnancy or breastfeeding. - Open wounds, ulcers, broken skin, active infection or severe dermatological conditions at or near the planned electrode sites on the feet or ankles. - Foot or leg pain judged to be primarily attributable to a non-neuropathic cause, such as acute trauma, severe peripheral arterial disease, active infection, or recent surgery. - Current or recent use of a TENS or other electrical stimulation device for pain management. - Severe motor impairment limiting safe participation. - Musculoskeletal conditions that would make seated participation for the duration of the session unsafe or uncomfortable. - Any other condition that, in the judgement of the investigators, would interfere with safe completion of the study procedures, including severe cognitive impairment.
Outcome results
None listed