Diabetic NeuropathiesNCT07807748
Effect of TENS on Sensory Parameters in Diabetic Polyneuropathy
A study testing High-Frequency TENS and Low-Frequency TENS in people with Diabetic Neuropathies and Diabetic Neuropathy, Painful, run by Burdur Mehmet Akif Ersoy University at 1 site in Turkey (Türkiye).
Trial summary
Diabetic polyneuropathy is a common complication of diabetes that damages the nerves of the feet and legs. Besides causing pain, it gradually reduces the ability to feel light touch on the sole of the foot. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Diabetic Neuropathies, Diabetic Neuropathy, Painful, Peripheral Nervous System Diseases
- What is being tested?
- High-Frequency TENS and Low-Frequency TENS
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 30 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 6 Sep 2021to 1 Nov 2021
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Type 1 or type 2 diabetes mellitus
- Clinically confirmed diabetic peripheral polyneuropathy of at least five years' duration, diagnosed by an endocrinologist during routine outpatient follow-up on the basis of distal symmetric sensory symptoms together with abnormal bedside sensory testing
- Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) score of 9 or above
- Standardized Mini-Mental State Examination score above 24
- Glycated haemoglobin (HbA1c) below 8.5%
- Wagner grade 0 feet (intact plantar skin without ulceration)
- Willing to continue prescribed diet and hypoglycaemic treatment unchanged throughout the study
Who cannot join
- Use of a cardiac pacemaker
- Alcohol dependence
- Peripheral arterial disease
- Renal failure
- Hepatic failure
- Hypothyroidism
Show all 13Show fewer
- Vitamin B12 deficiency
- Folate deficiency
- Sarcoidosis
- Active infection
- Malignancy
- Coagulopathy
- Skin lesion, discolouration, or allergic reaction at the electrode sites
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Effect of Transcutaneous Electrical Nerve Stimulation on Sensory Parameters in Patients With Diabetic Polyneuropathy: A Randomized, Double-Blind, Sham-Controlled Trial
Diabetic polyneuropathy is a common complication of diabetes that damages the nerves of the feet and legs. Besides causing pain, it gradually reduces the ability to feel light touch on the sole of the foot. This loss of protective sensation is important because it removes the warning signal that normally prevents unnoticed injuries, which can lead to foot ulcers.
Transcutaneous electrical nerve stimulation (TENS) is a non-drug treatment that delivers mild electrical currents through the skin using surface electrodes. It is inexpensive, widely available, and generally well tolerated. Most previous studies of TENS in diabetic polyneuropathy have looked at whether it relieves pain. Far less is known about whether it affects touch sensation, and whether the frequency of the stimulation matters.
Read more
This study compares three groups of patients with long-standing diabetic polyneuropathy. One group receives high-frequency TENS (100 Hz), one receives low-frequency TENS (5 Hz), and one receives sham stimulation at an intensity too low to have a treatment effect. Treatment is given five days a week for eight weeks, with electrodes placed on the calf and the sole of the foot.
The main measure is the lightest touch a participant can feel on the big toe, tested with Semmes-Weinstein monofilaments before and after the eight-week period. Additional measures include electrical and pressure pain thresholds and questionnaires on pain, mood, and quality of life. Participants and the researchers performing the assessments do not know which group each participant is in.
Read the detailed description
BACKGROUND AND RATIONALE
Distal symmetric polyneuropathy is the most common chronic complication of diabetes and the principal cause of the sensory loss that precedes foot ulceration. Current management is directed almost entirely at symptomatic control of neuropathic pain and is not expected to modify sensory function. Transcutaneous electrical nerve stimulation (TENS) has been studied in this population, but trials have used pain intensity or composite symptom scores as endpoints, and cutaneous sensory function has rarely been treated as a prespecified outcome.
Stimulation frequency provides a mechanistic rationale for outcomes that may differ in kind. Conventional high-frequency, sensory-intensity TENS preferentially recruits large-diameter, low-threshold A-beta afferents, whereas low-frequency, higher-intensity stimulation is generally attributed to endogenous opioid-mediated descending inhibition. The A-beta population engaged by the former is the same population that mediates detection of weak mechanical stimuli and that monofilament testing assesses. Converging evidence from the repetitive sensory stimulation literature indicates that prolonged, passive peripheral input can lower tactile thresholds through long-term-potentiation-like mechanisms, with a frequency dependence paralleling the induction of synaptic potentiation and depression.
DESIGN
Single-centre, randomised, double-blind, sham-controlled, parallel-group trial with three arms allocated in a 1:1:1 ratio. Participants were recruited from the Endocrinology and Metabolism outpatient clinic of Akdeniz University Faculty of Medicine; assessments were performed at the Akdeniz University Sports Sciences Research and Application Centre.
ALLOCATION AND BLINDING
Allocation was performed by a lot-drawing procedure after written informed consent and before baseline assessment. Simple randomisation was used, without blocking or stratification. Participants and outcome assessors were blinded to group assignment. The sham arm followed an identical procedure at a sub-therapeutic intensity, so participants were unaware of whether they received active or sham stimulation. All sensory, nociceptive, and questionnaire-based assessments were performed by evaluators blinded to allocation.
INTERVENTIONS
TENS was delivered with a dual-channel PRIMERA TENS/NMES stimulator (DJO, LLC, USA) using standard 2-inch self-adhesive electrodes, one placed on the calf and one on the plantar surface of the foot. A zero-direct-current, asymmetric biphasic rectangular waveform was used. Intensity was individually adjusted to each participant's sensory tolerance and maintained at a comfortable level throughout each session. Sessions were delivered five days per week for eight weeks in all arms.
ASSESSMENTS
Assessments were performed at baseline and repeated in the week following the eight-week programme. The primary outcome was the tactile detection threshold at the plantar surface of the great toe, measured with Semmes-Weinstein monofilaments (index 1.65-6.65), with the corresponding buckling force recorded in grams; a higher value indicates a more impaired threshold. All monofilament measurements were obtained by a single blinded investigator.
Secondary outcomes were exploratory and comprised electrical pain detection and tolerance thresholds obtained by transcutaneous sural nerve stimulation using an ascending method of limits; the nociceptive flexion reflex recorded by surface electromyography from the short head of the biceps femoris; pressure pain threshold and tolerance measured by digital algometry at the dominant forearm and leg; and patient-reported measures of neuropathic pain, pain quality, depressive symptoms, and quality of life.
STATISTICAL APPROACH
Non-parametric methods were planned throughout because of small, unequal group sizes and the expected right-skew of several sensory variables. Continuous variables are summarised as median with interquartile range. Within-group change was tested with the Wilcoxon signed-rank test and between-group differences at post-treatment with the Kruskal-Wallis test, followed for the primary outcome by prespecified Mann-Whitney contrasts of each active arm against sham. Benjamini-Hochberg false-discovery-rate correction was applied across the exploratory secondary family.
- Being tested
- High-Frequency TENS, Low-Frequency TENS, Sham TENS
- Medical subject headings
- Diabetic Neuropathies, Peripheral Nervous System Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
High-Frequency TENSDevice
Also called HF-TENS; Conventional TENS
Transcutaneous electrical nerve stimulation delivered with a dual-channel PRIMERA TENS/NMES stimulator (DJO, LLC, USA) using standard 2-inch self-adhesive electrodes, one placed on the calf and one on the plantar surface of the foot. Stimulation was delivered at 100 Hz with a pulse width of 200 microseconds for 30 minutes per session, using a zero-direct-current, asymmetric biphasic rectangular waveform. Intensity was individually adjusted to each participant's sensory tolerance. Sessions were delivered five days per week for eight weeks.
Low-Frequency TENSDevice
Also called LF-TENS; Acupuncture-like TENS
Transcutaneous electrical nerve stimulation delivered with the same device, electrode type, and electrode placement as the high-frequency arm. Stimulation was delivered at 5 Hz with a pulse width of 175 microseconds for 15 minutes per session, using a zero-direct-current, asymmetric biphasic rectangular waveform. Intensity was individually adjusted to each participant's sensory tolerance. Sessions were delivered five days per week for eight weeks.
Sham TENSDevice
Sham stimulation delivered with the same device, electrode type, and electrode placement as the active arms, at a sub-therapeutic intensity (approximately 2-3 mA) insufficient to produce a physiological effect. All other aspects of the procedure were identical to the low-frequency arm, including session duration and schedule. Sessions were delivered five days per week for eight weeks.
| Study group | Role | What they receive |
|---|---|---|
| High-Frequency TENS | Experimental | Conventional high-frequency TENS delivered at 100 Hz with a pulse width of 200 microseconds for 30 minutes per session. One electrode was placed on the calf and one on the plantar surface of the foot. A zero-direct-current, asymmetric biphasic rectangular waveform was used. Intensity was individually adjusted to each participant's sensory tolerance and maintained at a comfortable level throughout the session. Sessions were delivered five days per week for eight weeks. Receives: Device: High-Frequency TENS |
| Low-Frequency TENS | Experimental | Low-frequency TENS delivered at 5 Hz with a pulse width of 175 microseconds for 15 minutes per session. One electrode was placed on the calf and one on the plantar surface of the foot. A zero-direct-current, asymmetric biphasic rectangular waveform was used. Intensity was individually adjusted to each participant's sensory tolerance and maintained at a comfortable level throughout the session. Sessions were delivered five days per week for eight weeks. Receives: Device: Low-Frequency TENS |
| Sham TENS | Sham comparator | Sham stimulation delivered at a sub-therapeutic intensity (approximately 2-3 mA) insufficient to produce a physiological effect, with all other aspects of the procedure identical to the low-frequency arm, including electrode placement, session structure, and schedule. Sessions were delivered five days per week for eight weeks. Receives: Device: Sham TENS |
What is being measured
The primary outcome is the main question the study is designed to answer.
Tactile detection threshold at the plantar great toe
Cutaneous touch sensation assessed with Semmes-Weinstein monofilaments (index 1.65-6.65) applied to the plantar surface of the right great toe, with the corresponding buckling force recorded in grams. A higher value indicates a more impaired (less sensitive) threshold. All measurements were obtained by a single investigator blinded to group allocation.
Measured: Baseline and within one week after the end of the eight-week intervention period
Secondary outcomes (8)
Electrical pain detection threshold (ePDT)
Lowest current at which a transcutaneous electrical stimulus applied over the retromalleolar course of the sural nerve was first reported as painful, recorded in milliamperes. Stimuli consisted of trains of six
1-ms rectangular pulses at 250 Hz; current was increased from 1 mA in 1-mA steps using an ascending method of limits.
Measured: Baseline and within one week after the end of the eight-week intervention period
Electrical pain tolerance threshold (ePTT)
Highest current the participant was willing to accept during ascending transcutaneous sural nerve stimulation, recorded in milliamperes. At tolerance, participants rated perceived stimulus intensity on a 0-10 sensory analogue scale.
Measured: Baseline and within one week after the end of the eight-week intervention period
Nociceptive flexion reflex (RIII) threshold
Threshold for the nociceptive flexion reflex, assessed by surface electromyography from the short head of the ipsilateral biceps femoris during ascending transcutaneous sural nerve stimulation, recorded in milliamperes.
Measured: Baseline and within one week after the end of the eight-week intervention period
Pressure pain threshold (PPT)
Load at which pressure applied by a digital algometer with a
1 cm2 application surface at a rate of 1 kg/s was first perceived as painful, recorded in kilograms, from flexor and extensor muscle and myofascial regions of the dominant forearm and leg. Each site was measured twice and the lowest value recorded.
Measured: Baseline and within one week after the end of the eight-week intervention period
Pressure pain tolerance threshold (PPTO)
Load at which pressure applied by digital algometry could no longer be tolerated, recorded in kilograms, from the same sites as the pressure pain threshold. Each site was measured twice and the highest value recorded.
Measured: Baseline and within one week after the end of the eight-week intervention period
Neuropathic pain score (LANSS)
Leeds Assessment of Neuropathic Symptoms and Signs, a validated scale combining self-reported sensory descriptors with bedside sensory testing. Scores range from 0 to 24; a score of 12 or above indicates pain of predominantly neuropathic origin.
Measured: Baseline and within one week after the end of the eight-week intervention period
Pain quality (McGill Pain Questionnaire)
McGill-Melzack Pain Questionnaire, assessing sensory, affective, and evaluative dimensions of pain experience. Pain quality was assessed with the validated Turkish version of the long-form McGill-Melzack Pain Questionnaire. Participants select the words that best describe their pain from 20 descriptor subclasses, and the Pain Rating Index (PRI) is calculated as the sum of the rank values of the chosen words. The sensory (subclasses 1-10; range 0-42), affective (subclasses 11-15; range 0-14), evaluative (subclass 16; range 0-5), and miscellaneous (subclasses 17-20; range 0-17) dimensions are summed to give the total PRI score, which ranges from 0 (minimum) to 78 (maximum). Higher scores indicate a more severe and more complex pain experience (worse outcome).
Measured: Baseline and within one week after the end of the eight-week intervention period
Depressive symptoms (Beck Depression Inventory)
Modified Beck Depression Inventory, a self-report measure of depressive symptom severity. Depressive symptom severity was assessed with the validated Turkish version of the Beck Depression Inventory, a 21-item self-report questionnaire. Each item is scored from 0 to 3, and item scores are summed to give a total score ranging from 0 (minimum) to 63 (maximum). Higher scores indicate more severe depressive symptoms (worse outcome).
Measured: Baseline and within one week after the end of the eight-week intervention period
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Sep 2026
- Study start6 Sep 2021
- Primary completion6 Sep 2021
- Study completion1 Nov 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Diabetic NeuropathiesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 30 participants (actual)
Sponsor and investigators
- Lead sponsor
- Burdur Mehmet Akif Ersoy University
- Sponsor type
- University, hospital or other
- Collaborators
- Akdeniz University
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07807748
- Sponsor's protocol ID
- AKDENIZ-KAEK-402
- Status last verified
- Sep 2026
- First submitted
- 2 Sep 2026
- Last updated
- 21 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: De-identified individual participant data underlying the published results, including primary and secondary outcome measures and baseline characteristics.
Study at a glance
From the registry record, last updated by the sponsor on 21 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Transcutaneous Electrical Nerve Stimulation on Sensory Parameters in Patients With Diabetic Polyneuropathy: A Randomized, Double-Blind, Sham-Controlled Trial
- ClinicalTrials.gov ID
- NCT07807748
- Acronym / sponsor ID
- AKDENIZ-KAEK-402
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 30 participants (actual)
- Lead sponsor
- Burdur Mehmet Akif Ersoy UniversityUniversity, hospital or other
- Collaborators
- Akdeniz University
- Study start
- 6 Sep 2021 (actual)
- Primary completion
- 6 Sep 2021 (actual)
- Study completion
- 1 Nov 2021 (actual)
- First posted
- 8 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Diabetic polyneuropathy is a common complication of diabetes that damages the nerves of the feet and legs. Besides causing pain, it gradually reduces the ability to feel light touch on the sole of the foot. This loss of protective sensation is important because it removes the warning signal that normally prevents unnoticed injuries, which can lead to foot ulcers.
Transcutaneous electrical nerve stimulation (TENS) is a non-drug treatment that delivers mild electrical currents through the skin using surface electrodes. It is inexpensive, widely available, and generally well tolerated. Most previous studies of TENS in diabetic polyneuropathy have looked at whether it relieves pain. Far less is known about whether it affects touch sensation, and whether the frequency of the stimulation matters.
This study compares three groups of patients with long-standing diabetic polyneuropathy. One group receives high-frequency TENS (100 Hz), one receives low-frequency TENS (5 Hz), and one receives sham stimulation at an intensity too low to have a treatment effect. Treatment is given five days a week for eight weeks, with electrodes placed on the calf and the sole of the foot.
The main measure is the lightest touch a participant can feel on the big toe, tested with Semmes-Weinstein monofilaments before and after the eight-week period. Additional measures include electrical and pressure pain thresholds and questionnaires on pain, mood, and quality of life. Participants and the researchers performing the assessments do not know which group each participant is in.
Detailed description
BACKGROUND AND RATIONALE
Distal symmetric polyneuropathy is the most common chronic complication of diabetes and the principal cause of the sensory loss that precedes foot ulceration. Current management is directed almost entirely at symptomatic control of neuropathic pain and is not expected to modify sensory function. Transcutaneous electrical nerve stimulation (TENS) has been studied in this population, but trials have used pain intensity or composite symptom scores as endpoints, and cutaneous sensory function has rarely been treated as a prespecified outcome.
Stimulation frequency provides a mechanistic rationale for outcomes that may differ in kind. Conventional high-frequency, sensory-intensity TENS preferentially recruits large-diameter, low-threshold A-beta afferents, whereas low-frequency, higher-intensity stimulation is generally attributed to endogenous opioid-mediated descending inhibition. The A-beta population engaged by the former is the same population that mediates detection of weak mechanical stimuli and that monofilament testing assesses. Converging evidence from the repetitive sensory stimulation literature indicates that prolonged, passive peripheral input can lower tactile thresholds through long-term-potentiation-like mechanisms, with a frequency dependence paralleling the induction of synaptic potentiation and depression.
DESIGN
Single-centre, randomised, double-blind, sham-controlled, parallel-group trial with three arms allocated in a 1:1:1 ratio. Participants were recruited from the Endocrinology and Metabolism outpatient clinic of Akdeniz University Faculty of Medicine; assessments were performed at the Akdeniz University Sports Sciences Research and Application Centre.
ALLOCATION AND BLINDING
Allocation was performed by a lot-drawing procedure after written informed consent and before baseline assessment. Simple randomisation was used, without blocking or stratification. Participants and outcome assessors were blinded to group assignment. The sham arm followed an identical procedure at a sub-therapeutic intensity, so participants were unaware of whether they received active or sham stimulation. All sensory, nociceptive, and questionnaire-based assessments were performed by evaluators blinded to allocation.
INTERVENTIONS
TENS was delivered with a dual-channel PRIMERA TENS/NMES stimulator (DJO, LLC, USA) using standard 2-inch self-adhesive electrodes, one placed on the calf and one on the plantar surface of the foot. A zero-direct-current, asymmetric biphasic rectangular waveform was used. Intensity was individually adjusted to each participant's sensory tolerance and maintained at a comfortable level throughout each session. Sessions were delivered five days per week for eight weeks in all arms.
ASSESSMENTS
Assessments were performed at baseline and repeated in the week following the eight-week programme. The primary outcome was the tactile detection threshold at the plantar surface of the great toe, measured with Semmes-Weinstein monofilaments (index 1.65-6.65), with the corresponding buckling force recorded in grams; a higher value indicates a more impaired threshold. All monofilament measurements were obtained by a single blinded investigator.
Secondary outcomes were exploratory and comprised electrical pain detection and tolerance thresholds obtained by transcutaneous sural nerve stimulation using an ascending method of limits; the nociceptive flexion reflex recorded by surface electromyography from the short head of the biceps femoris; pressure pain threshold and tolerance measured by digital algometry at the dominant forearm and leg; and patient-reported measures of neuropathic pain, pain quality, depressive symptoms, and quality of life.
STATISTICAL APPROACH
Non-parametric methods were planned throughout because of small, unequal group sizes and the expected right-skew of several sensory variables. Continuous variables are summarised as median with interquartile range. Within-group change was tested with the Wilcoxon signed-rank test and between-group differences at post-treatment with the Kruskal-Wallis test, followed for the primary outcome by prespecified Mann-Whitney contrasts of each active arm against sham. Benjamini-Hochberg false-discovery-rate correction was applied across the exploratory secondary family.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| High-Frequency TENS | Experimental | Device: High-Frequency TENSConventional high-frequency TENS delivered at 100 Hz with a pulse width of 200 microseconds for 30 minutes per session. One electrode was placed on the calf and one on the plantar surface of the foot. A zero-direct-current, asymmetric biphasic rectangular waveform was used. Intensity was individually adjusted to each participant's sensory tolerance and maintained at a comfortable level throughout the session. Sessions were delivered five days per week for eight weeks. |
| Low-Frequency TENS | Experimental | Device: Low-Frequency TENSLow-frequency TENS delivered at 5 Hz with a pulse width of 175 microseconds for 15 minutes per session. One electrode was placed on the calf and one on the plantar surface of the foot. A zero-direct-current, asymmetric biphasic rectangular waveform was used. Intensity was individually adjusted to each participant's sensory tolerance and maintained at a comfortable level throughout the session. Sessions were delivered five days per week for eight weeks. |
| Sham TENS | Sham comparator | Device: Sham TENSSham stimulation delivered at a sub-therapeutic intensity (approximately 2-3 mA) insufficient to produce a physiological effect, with all other aspects of the procedure identical to the low-frequency arm, including electrode placement, session structure, and schedule. Sessions were delivered five days per week for eight weeks. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Type 1 or type 2 diabetes mellitus
- Clinically confirmed diabetic peripheral polyneuropathy of at least five years' duration, diagnosed by an endocrinologist during routine outpatient follow-up on the basis of distal symmetric sensory symptoms together with abnormal bedside sensory testing
- Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) score of 9 or above
- Standardized Mini-Mental State Examination score above 24
- Glycated haemoglobin (HbA1c) below 8.5%
Key exclusion criteria (13 listed)
- Use of a cardiac pacemaker
- Alcohol dependence
- Peripheral arterial disease
- Renal failure
- Hepatic failure
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| High-Frequency TENSAlso: HF-TENS; Conventional TENSTranscutaneous electrical nerve stimulation delivered with a dual-channel PRIMERA TENS/NMES stimulator (DJO, LLC, USA) using standard 2-inch self-adhesive electrodes, one placed on the calf and one on the plantar surface of the foot. Stimulation was delivered at 100 Hz with a pulse width of 200 microseconds for 30 minutes per session, using a zero-direct-current, asymmetric biphasic rectangular waveform. Intensity was individually adjusted to each participant's sensory tolerance. Sessions were delivered five days per week for eight weeks. | Device | High-Frequency TENS |
| Low-Frequency TENSAlso: LF-TENS; Acupuncture-like TENSTranscutaneous electrical nerve stimulation delivered with the same device, electrode type, and electrode placement as the high-frequency arm. Stimulation was delivered at 5 Hz with a pulse width of 175 microseconds for 15 minutes per session, using a zero-direct-current, asymmetric biphasic rectangular waveform. Intensity was individually adjusted to each participant's sensory tolerance. Sessions were delivered five days per week for eight weeks. | Device | Low-Frequency TENS |
| Sham TENSSham stimulation delivered with the same device, electrode type, and electrode placement as the active arms, at a sub-therapeutic intensity (approximately 2-3 mA) insufficient to produce a physiological effect. All other aspects of the procedure were identical to the low-frequency arm, including session duration and schedule. Sessions were delivered five days per week for eight weeks. | Device | Sham TENS |
Primary outcome
Tactile detection threshold at the plantar great toe
Time frame: Baseline and within one week after the end of the eight-week intervention period
Cutaneous touch sensation assessed with Semmes-Weinstein monofilaments (index 1.65-6.65) applied to the plantar surface of the right great toe, with the corresponding buckling force recorded in grams. A higher value indicates a more impaired (less sensitive) threshold. All measurements were obtained by a single investigator blinded to group allocation.
8 secondary outcomes
Electrical pain detection threshold (ePDT)
Time frame: Baseline and within one week after the end of the eight-week intervention period
Electrical pain tolerance threshold (ePTT)
Time frame: Baseline and within one week after the end of the eight-week intervention period
Nociceptive flexion reflex (RIII) threshold
Time frame: Baseline and within one week after the end of the eight-week intervention period
Pressure pain threshold (PPT)
Time frame: Baseline and within one week after the end of the eight-week intervention period
Pressure pain tolerance threshold (PPTO)
Time frame: Baseline and within one week after the end of the eight-week intervention period
Neuropathic pain score (LANSS)
Time frame: Baseline and within one week after the end of the eight-week intervention period
Pain quality (McGill Pain Questionnaire)
Time frame: Baseline and within one week after the end of the eight-week intervention period
Depressive symptoms (Beck Depression Inventory)
Time frame: Baseline and within one week after the end of the eight-week intervention period
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Sep 2026.
- Individual participant dataSharing planned: Yes. De-identified individual participant data underlying the published results, including primary and secondary outcome measures and baseline characteristics.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing High-Frequency TENS and Low-Frequency TENS in people with Diabetic Neuropathies and Diabetic Neuropathy, Painful, run by Burdur Mehmet Akif Ersoy University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 21 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Tactile detection threshold at the plantar great toe (time frame: Baseline and within one week after the end of the eight-week intervention period). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 Sep 2026.