At-home brain stimulation for chronic pelvic pain in endometriosis: a randomised controlled trial

ISRCTN ISRCTN15224642
DOI https://doi.org/10.1186/ISRCTN15224642
ClinicalTrials.gov (NCT) Nil known
Clinical Trials Information System (CTIS) Nil known
Integrated Research Application System (IRAS) 350170
Protocol serial number CPMS 64649
Sponsor Samphire Neuroscience Ltd
Funder Samphire Neuroscience Ltd
Submission date
02/03/2025
Registration date
04/03/2025
Last edited
07/11/2025
Recruitment status
Recruiting
Overall study status
Ongoing
Condition category
Urological and Genital Diseases
Prospectively registered
Protocol
Statistical analysis plan
Results
Individual participant data
Record updated in last year

Plain English summary of protocol

Background and study aims
Endometriosis is a common condition where tissue similar to the lining of the uterus grows outside the womb, often causing chronic pelvic pain (CPP) and negatively impacting quality of life. Current treatments, such as pain medication and hormone therapy, may not be effective for all patients and can have side effects. This study aims to investigate whether a non-invasive, at-home brain stimulation device (transcranial Direct Current Stimulation, tDCS) can help reduce pain and improve mood symptoms in women with endometriosis-related CPP.

Who can participate?
Women aged 18 to 50 years who have been diagnosed with endometriosis and experience chronic pelvic pain for more than three months are eligible to participate.

What does the study involve?
Participants will be randomly assigned to one of two groups:
1. Active treatment group – Participants will use the Nettle tDCS device at home for 20 minutes per day for 20 days.
2. Sham control group – Participants will use the same device, but it will not deliver active stimulation.
The study is double-blind, meaning neither participants nor researchers will know which group a participant is in. All participants will complete daily symptom assessments on pain and mood through a smartphone app and attend follow-up assessments after one menstrual cycle.

What are the possible benefits and risks of participating?
- Potential benefits: If effective, the device may help reduce pain and improve mood symptoms in women with endometriosis without the side effects of medication.
- Possible risks: tDCS is considered safe, but some participants may experience mild skin irritation, tingling, or headaches at the electrode sites.

Where is the study run from?
The study is being conducted at University College London Hospital (UCLH) (UK)

When is the study starting and how long is it expected to run for?
March 2024 to September 2027.

Who is funding the study?
Samphire Neuroscience Ltd. (UK)

Who is the main contact?
Professor Ertan Saridogan, uclh.gynaeresearch@nhs.net

Contact information

Prof Ertan Saridogan
Scientific, Principal investigator

University College London Hospital, 250 Euston Road
London
NW1 2BU
United Kingdom

ORCiD logoORCID ID 0000-0001-9736-4107
Phone +44 20 3447 2611
Email uclh.gynaeresearch@nhs.net
Ms Emile Radyte
Public

85 Great Portland Street
London
W1W 7LT
United Kingdom

ORCiD logoORCID ID 0000-0002-2460-8016
Phone +44 7500114946
Email research@samphireneuro.com

Study information

Primary study designInterventional
Study designSingle-centre interventional double-blind randomized sham controlled trial
Secondary study designRandomised parallel trial
Study type Participant information sheet
Scientific titleAt-home transcranial direct current stimulation on endometriosis-related chronic pelvic pain: randomised, double-blind, sham-controlled trial
Study acronymENHANCE
Study objectivesAt-home transcranial direct current stimulation (tDCS) using the Nettle device reduces chronic pelvic pain (CPP) intensity in women with endometriosis compared to a sham stimulation.
Ethics approval(s)

Approved 05/12/2024, London - Riverside Research Ethics Committee (2 Redman Pl, Stratford Cross, London, E20 1JQ, United Kingdom; 44207 104 8243; riverside.rec@hra.nhs.uk), ref: 24/PR/1445

Health condition(s) or problem(s) studiedManagement of endometriosis-related chronic pelvic pain (CPP).
InterventionThe study is a randomised, double-blind, sham-controlled trial evaluating the effectiveness of at-home transcranial direct current stimulation (tDCS) for chronic pelvic pain (CPP) in women with endometriosis. Participants will be randomised into two arms:
1. Active tDCS Group – Participants will receive daily 20-minute sessions of active tDCS using the Nettle device for 20 consecutive days. The device targets the primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) to modulate pain perception and mood symptoms.
2. Sham Control Group – Participants will use the same device for 20 minutes daily for 20 days, but without active stimulation, ensuring blinding.

Randomisation was carried out using the Excel randomisation formula, by a senior member of the team.
Intervention typeDevice
PhaseNot Applicable
Drug / device / biological / vaccine name(s)Nettle
Primary outcome measure(s)

Pain is measured using the Numerical Rating Scale (NRS) at baseline, daily during the 20-day intervention, post-intervention (Day 20), and one menstrual cycle post-intervention.

Key secondary outcome measure(s)

1. Pain catastrophising measured using the Pain Catastrophising Scale (PCS) at baseline, post-intervention (Day 20), and one menstrual cycle post-intervention.
2. Quality of life measured using the Endometriosis Health Profile-30 (EHP-30) at baseline, post-intervention (Day 20), and one menstrual cycle post-intervention.
3. Positive and negative affect measured using the Positive and Negative Affect Schedule (PANAS) at baseline, post-intervention (Day 20), and one menstrual cycle post-intervention.
4. State and trait anxiety measured using the State-Trait Anxiety Inventory (STAI) at baseline, post-intervention (Day 20), and one menstrual cycle post-intervention.
5. Depressive symptoms measured using the Beck Depression Inventory (BDI) at baseline, post-intervention (Day 20), and one menstrual cycle post-intervention.
6. Premenstrual symptom severity measured using the Daily Record of Severity of Problems (DRSP) continuously throughout the intervention and one menstrual cycle post-intervention.
7. Daily medication use recorded using the Daily Medication Diary daily during the intervention and one menstrual cycle post-intervention.

Added 07/11/2025:
8. Health-related quality of life measured using the EuroQol 5-Dimension 5-Level (EQ-5D-5L) at baseline, post-intervention (Day 20), and one menstrual cycle post-intervention.

Completion date17/09/2027

Eligibility

Participant type(s)Patient
Age groupAdult
Lower age limit18 Years
Upper age limit50 Years
SexFemale
Target sample size at registration40
Key inclusion criteria1. Women aged 18 to 50 years.
2. Confirmed diagnosis of endometriosis based on previous surgery, histology, MRI, or ultrasound findings.
3. Experiencing chronic pelvic pain (CPP) associated with endometriosis, defined as pain persisting for more than three months in the past six months with an intensity of at least 3 out of 10 on the Numerical Rating Scale (NRS).
4. Ability to complete symptom questionnaires and follow study procedures.
5. Capacity to provide informed consent for medical investigation and treatment.
6. Access to a compatible smartphone (Android or Apple) capable of hosting the study application.
Key exclusion criteria1. Severe or untreated neurological disease, such as subarachnoid haemorrhage or multiple sclerosis.
2. History of brain surgery, brain tumors, or intracranial metal implants.
3. History of stroke or head trauma.
4. History of epilepsy.
5. Active skin lesions, infections, open wounds, or cuts on the scalp.
6. Scalp conditions such as dermatitis, eczema, psoriasis, significant scarring, burns, or other forms of skin damage in areas where electrodes are placed.
7. Presence of brain implants.
8. Severe and/or untreated psychiatric illness, such as schizophrenia.
9. Metal implants or pacemakers, including implanted cardiac devices.
10. Pregnancy or plans to become pregnant within the next 12 months.
11. Currently breastfeeding.
12. Lack of capacity to consent.
Date of first enrolment04/03/2025
Date of final enrolment01/01/2026

Locations

Countries of recruitment

  • United Kingdom
  • England

Study participating centre

University College London Hospitals NHS Foundation Trust
250 Euston Road
London
NW1 2PG
United Kingdom

Results and Publications

Individual participant data (IPD) Intention to shareNo
IPD sharing plan summaryNot expected to be made available
IPD sharing planThe datasets generated during and/or analysed during the current study are not expected to be made available due to patient confidentiality considerations, ethical restrictions, and data protection regulations (including GDPR and the UK Data Protection Act 2018).

All collected participant-level data will be securely stored and used solely for study analysis and regulatory compliance. Aggregated, de-identified results will be shared through peer-reviewed publications and conference presentations, but individual participant data (IPD) will not be publicly available. If future amendments allow for data sharing, appropriate consent and anonymisation measures will be implemented.

Study outputs

Output type Details Date created Date added Peer reviewed? Patient-facing?
Participant information sheet Participant information sheet 11/11/2025 11/11/2025 No Yes

Editorial Notes

07/11/2025: The date of final enrolment was changed from 17/11/2025 to 01/01/2026. The secondary outcome measures were updated.
13/05/2025: The following changes were made:
1. The overall study end date was changed from 17/09/2025 to 17/09/2027.
2. The recruitment end date was changed from 17/05/2025 to 17/11/2025.
03/03/2025: Trial's existence confirmed by the National Institute for Health and Care Research (NIHR) (UK).