Effect of transcutaneous electrical nerve stimulation on sensation thresholds in patients with painful diabetic neuropathy: an observational study

Perspectives of Rehabilitation in Diabetic Neuropathy

Abstract Diabetic Neuropathy (DN) is a complication that affects at least half of the patients with Diabetes Mellitus. Unlike other symptoms and signs that may sooner alarm the patients, DN manifestations tend to be rather silent, and so usually neglected by the patient for a long period of time, which can last for years. Therefore it’s a “hidden complication of diabetes” label. Unfortunately, it is only when symptoms already affect the quality of life that the treatment becomes challenging when it comes to speaking of either etiological, symptomatic or rehabilitation strategies. Early diagnosis can also be tricky while aiming for lifestyle corrections and proper individualized treatment strategies. Rehabilitation methods for DN aim especially towards the improvement of articulation mobility and muscular strength amelioration, the suggested brief review of literature promoting this part of therapy essential for both prevention and amelioration of overall morbidity. Keywords: diabetic neuropathy, physical therapy, interdisciplinary approach, quality of life,

Comparison of Efficacy of Nortriptyline Versus Transcutaneous Electrical Nerve Stimulation on Painful Peripheral Neuropathy in Patients with Diabetes

Background and aims: Diabetic peripheral neuropathic pain (DPNP) is one of the most common complications of diabetes and is difficult to treat. Existing treatments are often inadequate at controlling pain and limited by side-effects and drug tolerance. This study assessed the efficacy of nortriptyline versus Transcutaneous Electrical Nerve Stimulation (TENS) in patients with DPNP.

Material and method: This is a randomized clinical trial study conducted on 39 patients with DPNP referring to Golestan Hospital in Ahvaz in 2017. Patients were randomly treated with TENS (18 sessions, each session 30 minutes; n=20) or nortriptyline (25 to 75 mg, once daily; n=19) for 6 weeks. Patients were evaluated for side effects and pain relief using visual analog scale (VAS).

Results: There was a significant improvement in pain with both treatments compared with baseline (p˂0.001). The patients in nortriptyline group experienced more pain relief (7.21±1.51 to 0.84±1.34) than the TENS group (7.6±1.47 to 2.75 ±2.43) (P=0.001). The 50% pain relief was observed in 14 patients (73%) in nortriptyline group, 6 patients (30%) in TENS group. Moreover, the side effects were seen in 15% of TENS and 55% of patients in nortriptyline groups (P=0.019).

Conclusion: Both TENS and nortriptyline were effective and safe in the management of DPNP. But nortriptyline showed a better performance on pain relief.

Modification of electrical pain threshold by voluntary breathing-controlled electrical stimulation (BreEStim) in healthy subjects

BACKGROUND

Pain has a distinct sensory and affective (i.e., unpleasantness) component. BreEStim, during which electrical stimulation is delivered during voluntary breathing, has been shown to selectively reduce the affective component of post-amputation phantom pain. The objective was to examine whether BreEStim increases pain threshold such that subjects could have improved tolerance of sensation of painful stimuli.

METHODS

Eleven pain-free healthy subjects (7 males, 4 females) participated in the study. All subjects received BreEStim (100 stimuli) and conventional electrical stimulation (EStim, 100 stimuli) to two acupuncture points (Neiguan and Weiguan) of the dominant hand in a random order. The two different treatments were provided at least three days apart. Painful, but tolerable electrical stimuli were delivered randomly during EStim, but were triggered by effortful inhalation during BreEStim. Measurements of tactile sensation threshold, electrical sensation and electrical pain thresholds, thermal (cold sensation, warm sensation, cold pain and heat pain) thresholds were recorded from the thenar eminence of both hands. These measurements were taken pre-intervention and 10-min post-intervention.

RESULTS

There was no difference in the pre-intervention baseline measurement of all thresholds between BreEStim and EStim. The electrical pain threshold significantly increased after BreEStim (27.5±6.7% for the dominant hand and 28.5±10.8% for the non-dominant hand, respectively). The electrical pain threshold significantly decreased after EStim (9.1±2.8% for the dominant hand and 10.2±4.6% for the non-dominant hand, respectively) (F[1, 10] = 30.992, p = .00024). There was no statistically significant change in other thresholds after BreEStim and EStim. The intensity of electrical stimuli was progressively increased, but no difference was found between BreEStim and EStim.

CONCLUSION

Voluntary breathing controlled electrical stimulation selectively increases electrical pain threshold, while conventional electrical stimulation selectively decreases electrical pain threshold. This may translate into improved pain control.

Sensitivity and specificity of von Frey's hairs for the diagnosis of peripheral neuropathy in patients with type 2 diabetes mellitus

OBJECTIVE

The aim was to evaluate von Frey's hairs as a diagnostic tool for peripheral neuropathy in type-2 diabetes patients with symptoms typical for diabetic neuropathy with respect to nerve conduction studies (NCSs) and a combination of clinical examination and NCS.

PATIENTS AND METHODS

65 patients with type-2 diabetes (33 men) with mean age 62.1 (SD 6.5) years, mean diabetes duration 17.5 (SD 9) years and mean symptom duration 5.2 (SD 4.3) years were examined with the set of von Frey's hairs. Diabetic neuropathy was diagnosed trough Neuropathy Disability Score (NDS). NCSs were performed on ulnar, peroneal, tibial and sural nerves.

RESULTS

Sensitivity of von Frey's hairs vs. NCS as the gold standard ranged from 37% to 79% and specificity from 65% to 87%. Sensitivity vs. combination of NDS and NCS ranged from 38% to 85% and specificity from 62% to 85%.

CONCLUSIONS

Von Frey's hairs have moderate sensitivity and specificity for diagnosis of neurophysiological and also clinical neuropathy. Being a fast and easy-to-perform procedure, they could be appropriate as a screening test in clinical practice.