The Effect of Transcutaneous Electrical Nerve Stimulation on Sensory Parameters in Patients With Diabetic Polyneuropathy: A Randomized, Double-Blind, Sham-Controlled Trial
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 30
- 试验地点
- 1
- 主要终点
- Tactile detection threshold at the plantar great toe
研究概览
简要总结
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.
详细描述
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Double (Participant, Outcomes Assessor)
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •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
排除标准
- •Use of a cardiac pacemaker
- •Alcohol dependence
- •Peripheral arterial disease
- •Renal failure
- •Hepatic failure
- •Hypothyroidism
- •Vitamin B12 deficiency
- •Folate deficiency
- •Sarcoidosis
- •Active infection
- •Malignancy
- •Coagulopathy
- •Skin lesion, discolouration, or allergic reaction at the electrode sites
研究组 & 干预措施
High-Frequency TENS
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.
干预措施: High-Frequency TENS (Device)
Low-Frequency TENS
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.
干预措施: Low-Frequency TENS (Device)
Sham TENS
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.
干预措施: Sham TENS (Device)
结局指标
主要结局
Tactile detection threshold at the plantar great toe
时间窗: 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.
次要结局
- Electrical pain detection threshold (ePDT)(Baseline and within one week after the end of the eight-week intervention period)
- Electrical pain tolerance threshold (ePTT)(Baseline and within one week after the end of the eight-week intervention period)
- Nociceptive flexion reflex (RIII) threshold(Baseline and within one week after the end of the eight-week intervention period)
- Pressure pain threshold (PPT)(Baseline and within one week after the end of the eight-week intervention period)
- Pressure pain tolerance threshold (PPTO)(Baseline and within one week after the end of the eight-week intervention period)
- Neuropathic pain score (LANSS)(Baseline and within one week after the end of the eight-week intervention period)
- Pain quality (McGill Pain Questionnaire)(Baseline and within one week after the end of the eight-week intervention period)
- Depressive symptoms (Beck Depression Inventory)(Baseline and within one week after the end of the eight-week intervention period)