Abstract
Introduction:
Diabetic peripheral neuropathy (DPN) is a prevalent complication of chronic diabetes mellitus, resulting in sensory function deterioration primarily in the lower limbs. Current treatments, including anticonvulsants, antidepressants, and opioids, often have limited efficacy and potential adverse effects. Complementary and alternative medicine including hydrotherapy is gaining attention worldwide. Salt glow massage is one of the hydrotherapeutic modalities that combines the mechanical effects of massage and chemical effects of salt application to the skin. There is no previous study that reports the therapeutic effect of salt glow massage. This study aims to evaluate the effect of salt glow massage on nerve conduction in patients with DPN.
Methods:
A randomized controlled design will be adapted for this study. Subjects will be recruited by convenient sampling method and randomized into a study group and a control group. The study group will undergo 15 min of salt glow massage on alternate days, whereas the control group will undergo 15 min of neutral water application on alternate days for 2 weeks. Nerve conduction velocity and visual analog scale for pain and neuropathic symptoms will be assessed at baseline and 2 weeks after the intervention.
Discussion:
The result of this study is expected to elucidate the efficacy of salt glow massage in improving symptoms in patients with DPN. The findings could provide valuable insights into integrating hydrotherapeutic modalities into conventional diabetic neuropathy management, potentially enhancing patient outcomes and treatment adherence.
Conclusions:
The current study’s findings may provide insight into the effect of salt glow massage on nerve conduction velocity, pain and symptoms of DPN.
Introduction
Background and rationale
Diabetic peripheral neuropathy (DPN) is a common complication of chronic diabetes mellitus, characterized by the gradual deterioration of sensory function, typically beginning in the lower limbs.1,2 It presents as pain, often worsening at night, along with sensations of paresthesia, varying levels of numbness, and a burning sensation. 3 DPN affects approximately 50% of individuals, leading to significant health challenges, increased mortality, and a diminished quality of life. 4 In India, its prevalence ranges from 18.8% to 61.9%, 5 with a strong association with elevated blood sugar levels. Several factors contribute to the development of DPN, including oxidative stress damage, sorbitol accumulation, advanced glycosylated end products, disruptions in the hexosamine pathway, protein kinase C, and microvascular dysfunction.6,7 Diagnostic methods range from basic sensory tests to advanced nerve conduction studies, often using various scales and instruments to gauge the severity of neuropathic symptoms. 8 Managing DPN begins with achieving optimal glycemic control, implementing lifestyle modifications, and addressing pain management. 9 However, many individuals with painful DPN do not experience satisfactory pain relief with current medications such as anticonvulsants, antidepressants, opioids, and opioid-like analgesics. Although some drugs have demonstrated effectiveness in alleviating DPN pain, their use is limited due to adverse effects and the potential for addiction.10,11
Complementary and alternative medicine treatments have gained popularity for managing various neuropathies. One such approach is hydrotherapy, a naturopathic method that involves using water with varying temperatures, pressures, and durations.12,13 Salt glow massage or salt rub is one of the hydrotherapy treatment modalities in which wet salt is rubbed over legs and feet. The salt glow is an admirable means of producing a circulatory reaction; the salt acts as a chemical irritant to the skin in addition to mechanical stimulus produced by the rubbing of sharp crystals in contact with the surface of the body. 14
Previous studies show that warm saltwater foot baths reduce symptoms of painful DPN. 15 Earlier studies have reported the role of magnesium as an analgesic by blocking N-methyl-D-aspartate (NMDA) receptors and modulating calcium channels, reducing pain perception. It also serves as an anti-inflammatory substance by lowering proinflammatory cytokines and oxidative stress. 16 However, there is no scientific evidence reporting the therapeutic effects of salt glow massage. This is the first-ever study to evaluate the effect of salt glow massage on DPN.
Objectives
Primary objective
To study the effects of salt glow massage on nerve conduction velocity in patients with DPN.
Secondary objective
To assess the effect of salt glow massage on pain using the visual analog scale.
To assess the effect of salt glow massage on neuropathic symptoms using the DN4 questionnaire.
Trial design
A randomized control study design will be adopted. It will be conducted on patients with DPN. Participants will be randomly allocated to the study and control groups after an interview and obtaining informed consent. The study group will undergo 15 min of salt glow massage on alternate days for 2 weeks. The control group will undergo 15 min of neutral water application on alternate days for 2 weeks. Assessments will be taken on day 1 before the intervention and on day 14 after the intervention (Fig. 1).
Trial profile.
Methods: Participants, Intervention, and Outcomes
Study setting
The study will be conducted in a single center. Participants who are attending the outpatient department will be invited to participate in this study. All the assessments will be carried out in the research department.
Eligibility criteria
Patients who are diagnosed with DPN will be recruited to the study group and control group, according to the following inclusion and exclusion criteria.
Inclusion criteria
Age 30–70 years
Both gender
Known case of diabetic neuropathy clinically diagnosed either by the physician or by the DN4 questionnaire
A history of >3 months of sensory symptoms of diabetic neuropathy
Exclusion criteria
Participants with other sensory neurological complications
General contraindications (diabetic foot, open cuts, and wounds, varicosity, hypersensitive skin)
Participants with other systemic diseases
Pregnant women
Psychiatric illness
Interventions
Intervention description
Study group
The study group will undergo 15 min of salt glow massage as an intervention on alternate days for two weeks. The participants will be instructed to wash their legs and lie down in a supine position on the massage table. Epsom salt is applied with moist hands over the wet surface of the legs, and the Swedish massage will be given that includes the following movements (stroking, circular friction, longitudinal friction, kneading). This therapeutic regimen will be administered by the investigator in an outpatient clinical setting.
Control group
The control group will receive neutral water application (92°F–95°F) for 15 min on alternate days for 2 weeks.
Criteria for discontinuing or modifying allocated interventions
Participants are free to withdraw from the study at any point in time, for any reason, with or without prior intimation to the investigators. Participants can also discontinue if there are any severe adverse events (worsening of symptoms or skin abrasions) reported in the study group compared with the control group.
Strategies to improve adherence to the intervention
The investigators will periodically contact participants to ask them to attend the OPD on alternate days for 2 weeks. The participants will be able to contact the investigator throughout the study period to clarify doubts. If consent is granted, primary outcome data will be collected in patients who discontinue or deviate from the intervention protocol.
Relevant concomitant care permitted or prohibited during the trial
Concomitant care, along with conventional management, will be provided to both groups, which includes dietary advice and routine medication review and advice. All participants will be restricted from participating in other clinical studies.
Outcomes
Primary outcome
Nerve conduction velocity will be performed before the intervention on day 1 and after the intervention on day 14 using RMS Aleron 401 Electromyograph. It is the gold standard test for this purpose and plays a crucial role in the evaluation of the peripheral nervous system and obtaining accurate and objective data on neuropathies. Experts advocate the use of nerve conduction studies (NCS) as a reliable indicator of diabetic sensorimotor polyneuropathy (DSPN). 17 The tibial and common peroneal nerves are the two main motor nerves innervating the muscles in the lower leg and foot, causing muscle weakness or gait disturbance when injured or compromised. The sural and superficial peroneal nerves are the two main sensory nerves of the lower extremities, each branching from the tibial and the common peroneal nerves. 18
Secondary outcome
Pain will be assessed by visual analog scale, a self-reported measure of pain recorded with a single handwritten mark placed at one point along the length of a 10-cm line that represents a continuum between the two ends of the scale “no pain” on the left end (0 cm) and “worst pain” on the right end (10 cm). 19
Neuropathic symptoms will be assessed by DN4 questionnaire, which is both a screening and a diagnostic tool for painful diabetic polyneuropathy. 20
Participant timeline
Each participant will be screened and randomly allocated to the study and control groups. The study group participants will undergo intervention on alternate days for 2 weeks. A pre-post assessment will be taken on the first day before intervention and day 14 after intervention. Details of the study protocol are given in (Fig. 2).
Participant timeline.
Sample size
The sample size was 20 (study group =10) (control group = 10).
Sample size calculation
The sample size was calculated using G*Power 3.1.9.4. Considering the effect size of 1.83 from the previous study, 15 alpha value of 0.05, and power of 0.95, a sample of 7 per group was calculated. Assuming a 20% attrition rate and rounding off, a sample of 10 per group was finalized.
Recruitment
Patients with DPN who will attend the outpatient department will be invited to the study. An eligibility screening based on inclusion and exclusion criteria will be performed on participants who volunteer. They will be randomized to the study and control group after obtaining informed written consent.
Methods: Assignment of Interventions
Allocation
Sequence generation
Patients will be randomized to the study and control group with a one-to-one allocation ratio using a simple random method by computerized randomization.
Allocation concealment mechanism
Sealed envelopes will be prepared in advance, indicating each participant’s allocation based on their recruitment number. During the recruitment process, these envelopes will be handed to the researcher responsible for enrolling participants. Participants who meet the inclusion and exclusion criteria and provide informed consent will be assigned a unique recruitment number in chronological order. The corresponding sealed envelope for that recruitment number will then be opened, and based on its contents, participants will either begin the intervention or be assigned to the control group.
Implementation
A member of the study, who is not involved in participant recruitment, will generate the allocation sequence for assigning participants according to generated random numbers.
Blinding
The participants and the investigators will not be blinded due to the nature of the intervention. However, the assessor will be blinded to group allocation.
Methods: Data Collection, Management, and Analysis
Data collection methods
The data nerve conduction study will be performed using RMS Aleron 401 Electromyograph, pain will be assessed using visual analog scale, and neuropathic symptoms will be assessed using DN4 questionnaire on day 1 before and day 14 after the intervention.
Data management
All the data will be entered into Microsoft Excel 2011. It will be stored under password protection in a dedicated computer and kept confidential under the custody of the research department.
Statistical methods
Analysis will be done using Statistical Package for the Social Science, Version 16.0. Kolmogorov–Smirnov test will be done to check the normal distribution of the data. Based on the data distribution, within-group analysis will be done using paired-samples t-test or Wilcoxon signed rank test and between-group analysis will be done using independent samples t-test or Mann–Whitney U test. P value <0.05 will be considered significant.
Methods: Monitoring
Data monitoring
In the proposed study, data monitoring will be carried out by the primary investigator, and the quality control of the entire project will be monitored by the Head of the Department and Research guide to identify the problems in the project implementation process promptly and to implement the corresponding countermeasures. The researchers will be handling the control bias by examining and supervising the acquired data.
Harms
Participants who may be harmed will be excluded as per the study. Participants will also be monitored throughout the study for any adverse events. Serious adverse events will be reported to the ethics committee. The necessary actions will be taken, including further investigations and management steps.
Auditing
Auditing will be done promptly.
Protocol amendments
Approval for any protocol amendments will be communicated to the department and obtained from the institutional ethics committee (IEC). All protocol changes will be shared with participants, and their consent will be obtained before proceeding with the amendments.
Consent or assent
Written informed consent will be obtained from each participant by the principal investigators using a consent form after explaining and providing the information sheet.
Declaration of interests
The authors declare that they have no known competing financial and personal relationship that could have appeared to influence the work reported in this article.
Dissemination policy
The result of the study will be disseminated through conference presentations and publication in peer-reviewed indexed journals.
Discussion
This study is the first ever randomized controlled trial (RCT) that aimed to evaluate the effect of salt glow massage on DPN. Massage therapy enhances blood flow to both the skin and underlying tissues. This improved circulation augments the delivery of oxygen and nutrients to peripheral nerves, which supports nerve regeneration and enhances nerve conduction. 21 Such stimulation could aid in reconditioning nerve pathways affected by diabetic neuropathy, potentially improving nerve conduction and facilitating nerve repair. 22 Additionally, massage activates the skin’s sensory pathways through tactile stimulation. This activation can enhance nerve signaling and sensory perception in patients with diabetic neuropathy. Over time, consistent stimulation may condition the nerves to function more effectively, potentially leading to increased conduction velocity. 23
Salt possesses anti-inflammatory properties, and its application during massage may help mitigate local inflammation. By reducing inflammation, the massage can alleviate nerve compression and enhance nerve function, which might improve nerve conduction velocity in individuals with neuropathy. 24 During a salt glow massage, the mechanical pressure applied may stimulate the nerve endings in the skin, activating the peripheral nervous system. 14 Salt used in massage may contain trace minerals such as magnesium, which are crucial for nerve function. Magnesium has been shown to improve nerve conduction and reduce neuropathy symptoms by modulating cellular processes. Therefore, the presence of magnesium and other minerals in salt may contribute to overall nerve health, as deficiencies in these minerals are associated with impaired nerve conduction. 25
Limitations
Key limitations of the study protocol include a limited sample size that cannot be generalized, a brief intervention period, and a lack of follow-up.
Conclusions
This study is expected to elucidate the efficacy of salt glow massage in improving symptoms of DPN. The findings could provide valuable insights into integrating hydrotherapeutic modalities into conventional diabetic neuropathy management, potentially enhancing patient outcomes and treatment adherence.
Footnotes
Authors’ Contributions
Conceptualization, investigation, and writing: K.N. Conceptualization and methodology: A.K. Writing—original draft: S.G. Writing—original draft: Y.C. Review and editing: N.L. Review and editing: M.A. Supervision: N.M.
Author Disclosure Statement
No competing financial interests exist.
Funding Information
No funding was received for this article.