Median nerve diadynamic current stimulation for blood pressure modulation

Authors

DOI:

https://doi.org/10.3329/bsmmuj.v18i4.84473

Keywords

blood pressure, electrical stimulation, median nerve 

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Correspondence

Ramana Kameswarani
Email:academic2020research@gmail.com

Publication history

Received: 19 Sep 2025
Accepted: 4 Jan 2026
Published online: 16 Feb 2026

Responsible editor

Reviewers

Funding

None

Ethical approval

Approved by ISRB of Saveetha College of Physiotherapy, Ref no: 068/10/2024/ISRB/UGSR/SCPT, Dated 10 Oct 2024

Trial registration number

Not available 

Copyright

© The Author(s) 2026; all rights reserved
Published by Bangladesh Medical University (former Bangabandhu Sheikh Mujib Medical University).

Key messages
Diadynamic current median nerve stimulation affects cardiovascular autonomic output by activating axon-reflex and somato-autonomic pathways. We observed a statistically non-significant decrease in systolic blood pressure, but a increase in diastolic blood pressure in the single cross-over study. The results of this modulationis not conclusive for its use in the clinical settings. Further studies are necessary.

Electrical stimulation modifies peripheral nerve function and neuromuscular activity by applying controlled electrical currents through the skin [1]. Peripheral neuromodulation offers therapeutic promise for reestablishing physiological balance by using targeted nerve stimulation to control organ and tissue function through bidirectional brain–periphery transmission [2]. The somato-autonomic reflex involves central pathways in which somatosensory stimulation activates autonomic efferents through spinal and brainstem circuits, resulting in organ-specific or systemic cardiovascular responses [3]. The axon reflex is a peripheral process in which neuropeptides such as substance P and calcitonin gene-related peptide are released by sensory neurones antidromically to produce localised vasodilation or vasoconstriction without engaging the central nervous system [4]. Through somato-autonomic reflexes, median nerve stimulation may affect blood pressure. Axon-reflex activity and neurotransmitter release further limit presympathetic drive, supporting physiological blood pressure regulation, while afferent input activates central autonomic nuclei projecting to the rostral ventrolateral medulla, suppressing sympathetic outflow [5]. This study uniquely investigates diadynamic median nerve stimulation as a non-invasive method of reducing the sympathetic outflow and modulating blood pressure in a healthy adult.

An apparently healthy 19-year-old man with a body mass index of 23.5kg/m2, leading a healthy lifestyle was selected. Comorbid conditions like hypertension, diabetes, and autonomic dysfunction were excluded to provide more reliable physiological responses [6]. Ethical guidelines were adhered to, and an informed consent was obtained prior to commencing the study. This experimental design was adopted to evaluate the effects of diadynamic stimulation on blood pressure regulation. Systolic and diastolic blood pressure were measured using a digital sphygmomanometer (Omron HEM-7120).

Blood pressure measurements were taken on the same arm, after a 5-minute seated rest, at approximately the same time of day. Three readings were taken, with the average value used for analysis. This procedure was replicated during pre- and post-intervention as well as during the baseline/washout weeks. The intervention was conducted over five successive weeks. Systolic and diastolic blood pressures were measured at six time points at one-week intervals: baseline, intervention 1 (week 1), washout (week 2), intervention 2 (week 3), washout (week 4), and endline (week 5). The intervention consisted of applying diphase diadynamic current via surface electrodes placed bilaterally at the volar aspect of the wrist, over the median nerve distribution at the base of the thumb. For the diphase waveform, intensity was set to a comfortable sensory level, individualised to the participant's comfort.

The stimulation frequency was pre-set according to the device’s diphase mode using the BTL-4825SL unit and each session lasted 10 minutes. Baseline blood pressure was recorded at Week 0. Diadynamic current stimulation was applied in Weeks 1 and 3 with pre- and post-treatment measurements. Weeks 2 and 4 served as washout periods. Final blood pressure was recorded at Week 5. The one-week interval for a washout was based on previous studies that reported that seven days were long enough to minimise carryover effects in short-duration physiological interventions, and residual changes across the washout phases were visually checked to determine the appropriateness of the interval [7]. To enhance internal validity, the common acute blood-pressure influencers were monitored daily. The participant was instructed to maintain typical daily routines throughout the study in order to minimise variability in behaviour between phases and was closely monitored during every session for comfort and safety.

Table 1 Intervention phases and blood pressure measurements of a 19-year-old man

Week

Phase

 

Blood pressure (mmHg)

 

 

 

Systolic

Diastolic

Pre-test

Baseline

–

121

65

Week 1

Intervention

Pre

127

67

 

 

Post

119

66

Week 2

Washout

–

128

69

Week 3

Intervention

Pre

131

78

 

 

Post

134

64

Week 4

Washout

–

124

67

Post-test

Follow-up

–

118

69

Categories

Number (%)

Sex

 

   Male

36 (60.0)

   Female

24 (40.0)

Age in yearsa

8.8 (4.2)

   Education

 

   Pre-school

20 (33.3)

   Elementary school

24 (40.0)

   Junior high school

16 (26.7)

Cancer diagnoses

 

   Acute lymphoblastic leukemia

33 (55)

   Retinoblastoma

5 (8.3)

   Acute myeloid leukemia

4 (6.7)

   Non-Hodgkins lymphoma

4 (6.7)

   Osteosarcoma

3 (5)

   Hepatoblastoma

2 (3.3)

   Lymphoma

2 (3.3)

   Neuroblastoma

2 (3.3)

   Medulloblastoma

1 (1.7)

   Neurofibroma

1 (1.7)

   Ovarian tumour

1 (1.7)

   Pancreatic cancer

1 (1.7)

   Rhabdomyosarcoma

1 (1.7)

aMean (standard deviation)

Categories

Number (%)

Sex

 

   Male

36 (60.0)

   Female

24 (40.0)

Age in yearsa

8.8 (4.2)

Education

 

   Pre-school

20 (33.3)

   Elementary school

24 (40.0)

   Junior high school

16 (26.7)

Cancer diagnoses

 

Acute lymphoblastic leukemia

33 (55)

Retinoblastoma

5 (8.3)

Acute myeloid leukemia

4 (6.7)

Non-Hodgkins lymphoma

4 (6.7)

Osteosarcoma

3 (5)

Hepatoblastoma

2 (3.3)

Lymphoma

2 (3.3)

Neuroblastoma

2 (3.3)

Medulloblastoma

1 (1.7)

Neurofibroma

1 (1.7)

Ovarian tumour

1 (1.7)

Pancreatic cancer

1 (1.7)

Rhabdomyosarcoma

1 (1.7)

aMean (standard deviation)

Pain level

Number (%)

P

Pre

Post 1

Post 2

Mean (SD)a pain score

4.7 (1.9)

2.7 (1.6)

0.8 (1.1)

<0.001

Pain categories

    

   No pain (0)

-

1 (1.7)

31 (51.7)

<0.001

   Mild pain (1-3)

15 (25.0)

43 (70.0)

27 (45.0)

 

   Moderete pain (4-6)

37 (61.7)

15 (25.0)

2 (3.3)

 

   Severe pain (7-10)

8 (13.3)

2 (3.3)

-

 

aPain scores according to the visual analogue scale ranging from 0 to 10; SD indicates standard deviation

The blood pressure values during baseline and intervention phases are presented in Table 1. Tau-U was used for statistical analysis as it is a non-parametric effect size measure designed for single-case experimental designs. It compares baseline and intervention values pairwise to quantify phase non-overlap, yielding a standardised effect size [8]. The systolic blood pressure was decreased (Week-5 minus baseline) by 3 mmHg but diastolic blood pressure was increased by 5 mmHg. None of these changes were statistically significant.

Following diadynamic current median nerve stimulation, an effect on blood pressure regulation appeared to manifest across the subsequent intervention phases but none of them were sustained for statistical significance. Contrary to the findings of other studies, the diastolic pressure increased paradoxically. This divergent diastolic response may suggest our inability to control extraneous factors in the statistical analysis.

It is hypothesised that diadynamic current changes the autonomic outflow by exciting cuta-neous and afferent nerve fibers. Thus, the balance shifts to increased parasympathetic and reduced sympathetic activity [9]. However, the present findings indicate a possible autonomic influence of diadynamic current stimulation, which requires further controlled studies to recommend any therapeutic indication. Subsequent studies may require an adjustment of dosages of electrical stimulation and other indices such as intensity, frequency and duration of the sessions that cause maximal blood pressure changes without provoking side effect or discomfort using a design that can adjust the results for extraneous factors such as objectively measured caffeine and salt intake and physical activity before the measurement of blood pressure.

Acknowledgements
It is a privilege to express my sincere gratitude to the department and to all those who have played a significant role in shaping the foundation of this study.
Author contributions
Conception or design of the work; or the acquisition, analysis, or interpretation of data for the work: RSS, RK, PBRP. Drafting the work or reviewing it critically for important intellectual content: RSS, RK, PBRP. Final approval of the version to be published: RSS. Accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved: RSS, RK, PBRP.
Conflict of interest
We do not have any conflict of interest.
Data availability statement
We confirm that the data supporting the findings of the study will be shared upon reasonable request.
AI disclosure
After completion of the manuscript, ChatGPT (OpenAI) was used solely for language polishing and grammatical refinement. We critically reviewed and edited all content and take full responsibility for the integrity, accuracy, and originality of the published work.
Supplementary file
None
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