Functional and Affective Effects of a Brief tDCS Intervention in Fibromyalgia and Chronic Fatigue Syndrome (FibFatDCS)

Functional and Affective Effects of a brief tDCS Intervention in Fibromyalgia and Chronic Fatigue Syndrome Fibromyalgia (FM) and chronic fatigue syndrome (CFS) are characterized by persistent, multidimensional symptoms arising from complex brain-body interactions that impair functioning and quality of life. Noninvasive neuromodulation techniques such as transcranial direct current stimulation (tDCS) have been proposed as adjunctive approaches to support short-term functional changes within distributed neural systems, although evidence remains limited and heterogeneous. The objective is to examine immediate pre-post changes in multidimensional clinical outcomes following a standardized tDCS protocol in patients with FM and CFS, and to explore potential diagnosis-related response patterns.

Study Overview

• Status: Terminated
• Conditions: Chronic Fatigue Syndrome (CFS); Fibromyalgia (FM)
• Intervention / Treatment: Device: Transcraneal Direct Current Electric Stimulation (tDCS); Device: Transcranial Direct Current Electric Stimulation (tDCS)

Detailed Description

Abstract Background: Fibromyalgia (FM) and chronic fatigue syndrome (CFS) are characterized by persistent, multidimensional symptoms arising from complex brain-body interactions that impair functioning and quality of life. Noninvasive neuromodulation techniques such as transcranial direct current stimulation (tDCS) have been proposed as adjunctive approaches to support short-term functional changes within distributed neural systems, although evidence remains limited and heterogeneous. Objective: To examine immediate pre-post changes in multidimensional clinical outcomes following a standardized tDCS protocol in patients with FM and CFS, and to explore potential diagnosis-related response patterns. Methods: Fifteen patients (FM: n = 5; CFS: n = 10) received 10 sessions of tDCS (20 minutes per session) administered over two consecutive weeks (five sessions per week). Patient-reported outcomes were assessed at baseline and immediately after treatment completion. Measures included the Short Form-36 Health Survey (SF-36), Fibromyalgia Impact Questionnaire (FIQ), Hospital Anxiety and Depression Scale (HADS), Composite Autonomic Symptom Score (COMPASS), pain thermometer, Epworth Sleepiness Scale, Fatigue Severity Scale (FSS), and Fatigue Assessment Scale (FAS). Pre-post comparisons were conducted at the whole-sample level, followed by exploratory analyses stratified by diagnosis. Results: At baseline, patients with FM showed lower COMPASS, FSS, FAS, and HADS scores, and higher SF-36 scores, compared to patients with CFS, indicating a relatively less severe clinical profile. Across the sample, pre-post comparisons indicated improvements in FIQ and HADS scores. Exploratory group-specific analyses suggested that FM patients exhibited reductions in depressive symptoms, whereas CFS patients showed improvements in quality of life (SF-36) and functional impact (FIQ). No significant changes were observed in subjective pain intensity or fatigue severity (FSS). Conclusions: These findings suggest partially distinct clinical profiles and differential responsiveness to tDCS across FM and CFS, within the context of baseline differences between groups. Improvements appeared domain-specific, with affective symptoms responding in FM and functional outcomes in CFS, while core symptoms such as pain and fatigue remained unchanged over the intervention period. This pattern provides preliminary support for the idea that short-term neuromodulation may preferentially influence higher-order regulatory processes rather than core symptom generators, underscoring the need for tailored, multidimensional treatment approaches. Nevertheless, given the small sample size, absence of a control condition, and exploratory nature of subgroup analyses, these results should be interpreted with caution. Further controlled

studies are needed to clarify the reliability, specificity, and clinical relevance of these effects.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Spain
  • Gipuzkoa
    • San Sebastián, Gipuzkoa, Spain, 20250
      • Hospital Universitario de Donostia

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Diagnosis of Fibromyalgia
• Diagnosis of chronic fatigue syndrome

Exclusion Criteria:

• Having both conditions at the same time

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: The patients with Fibromyalgia; The same treatment is applied (tDCS)	Device: Transcraneal Direct Current Electric Stimulation (tDCS); It is an neuromodulation technic
Active Comparator: The patients with chronic fatigue syndrome; The same treatment is applied ( tDCS)	Device: Transcranial Direct Current Electric Stimulation (tDCS); It is a neuromodulation technic

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Visual Pain Scores (VAS)	It is measured before and inmediately after the treatment ( tDCS) is applied. (0-10) Higher scores mean more pain.	From enrollment to the end of treatment at 2 weeks
Fibromyalgia Impact Questionnaire (FIQ)	It measures the impact of fibromyalgia (Scores: 0-100) The FIQ is scored in such a way that a higher score indicates a greater impact of the syndrome on the person.	From enrollment to the end of treatment at 2 weeks

Collaborators and Investigators

• Sponsor: Hospital Donostia
• Investigators: Study Director: Adolfo Lopez de Munain, Doctor, University Hospital of Donostia; Study Director: PEDRO MONTOYA, UNIVERSITY OF BALEARIC ISLANDS, MALLORCA

Publications and helpful links

General Publications

• Moldofsky H. Fibromyalgia, sleep disorder and chronic fatigue syndrome. Ciba Found Symp. 1993;173:262-71; discussion 272-9. doi: 10.1002/9780470514382.ch15. PMID: 8491102.
• McHorney CA, Ware JE Jr, Lu JF, Sherbourne CD. The MOS 36-item Short-Form Health Survey (SF-36): III. Tests of data quality, scaling assumptions, and reliability across diverse patient groups. Med Care. 1994 Jan;32(1):40-66. doi: 10.1097/00005650-199401000-00004. PMID: 8277801.
• Lloyd, D. M., Wittkopf, P. G., Arendsen, L. J., & Jones, A. K. P. (2020). Is transcranial direct current stimulation (tDCS) effective for the treatment of pain in fibromyalgia? A systematic review and meta-analysis. The Journal of Pain, 21(11-12), 1085-1100. https://doi.org/10.1016/j.jpain.2020.01.003
• Lerdal A, Kottorp A. Psychometric properties of the Fatigue Severity Scale-Rasch analyses of individual responses in a Norwegian stroke cohort. Int J Nurs Stud. 2011 Oct;48(10):1258-65. doi: 10.1016/j.ijnurstu.2011.02.019. Epub 2011 Mar 16. PMID: 21414620.
• Hendriks C, Drent M, Elfferich M, De Vries J. The Fatigue Assessment Scale: quality and availability in sarcoidosis and other diseases. Curr Opin Pulm Med. 2018 Sep;24(5):495-503. doi: 10.1097/MCP.0000000000000496. PMID: 29889115
• Hawker, G. A., et al. (2011).Measures of adult pain: Visual Analog Scale for Pain (VAS Pain). Arthritis Care & Research, 63(S11), S240-S252. https://doi.org/10.1002/acr.20543
• Committee on the Diagnostic Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome; Board on the Health of Select Populations; Institute of Medicine. Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. Washington (DC): National Academies Press (US); 2015 Feb 10. 7, Recommendations. Available from: https://www.ncbi.nlm.nih.gov/books/NBK284910/
• Burckhardt CS1, Clark SR, Bennett RM. The fibromyalgia impact questionnaire: development and validation.J Rheumatol. 1991 May;18(5):728-33.
• Bartholomew EJ, Medvedev ON, Petrie KJ, Chalder T. Rasch analysis of the hospital anxiety and depression scale in patients with chronic fatigue syndrome. J Psychosom Res. 2025 Oct;197:112370. doi: 10.1016/j.jpsychores.2025.112370. Epub 2025 Sep 3. PMID: 40939313.

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2025
• Primary Completion (Actual): May 1, 2025
• Study Completion (Actual): May 30, 2025

Study Registration Dates

• First Submitted: April 21, 2026
• First Submitted That Met QC Criteria: May 1, 2026
• First Posted (Actual): May 7, 2026

Study Record Updates

• Last Update Posted (Actual): May 7, 2026
• Last Update Submitted That Met QC Criteria: May 1, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: pain; fatigue; tdcs
• Additional Relevant MeSH Terms: Neuroinflammatory Diseases; Neurologic Manifestations; Musculoskeletal Diseases; Nervous System Diseases; Muscular Diseases; Pathologic Processes; Encephalomyelitis; Neuromuscular Diseases; Chronic Disease; Disease Attributes; Rheumatic Diseases; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain; Fatigue Syndrome, Chronic; Fibromyalgia; Fatigue
• Other Study ID Numbers: #061CER24; European Regional Development (Other Identifier: grant #PID2022-140561NB-I00.)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: IPD may be shared upon reasonable request, subject to ethical approval and data use agreements.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No