Pain perception and its influences in functional neurological disorder
| ISRCTN | ISRCTN44489307 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN44489307 |
- Submission date
- 17/02/2025
- Registration date
- 18/02/2025
- Last edited
- 03/03/2025
- Recruitment status
- Recruiting
- Overall study status
- Ongoing
- Condition category
- Mental and Behavioural Disorders
Plain English summary of protocol
Background and study aims
Functional neurological disorder (FND) symptoms may arise from changes in brain function rather than disease processes with structural damage to the nervous system. One key idea in understanding FND is that the brain plays an active role in shaping perception, movement, and bodily sensations. By understanding how the relevant psychological and physiological factors shape pain experience in FND, this study hopes to gain insights into the mechanisms behind symptom generation and identify new strategies to support patients.
Who can participate?
Adults aged between 18 and 65 years old can take part. One group includes people diagnosed with FND, and the other group consists of non-clinical (healthy volunteer) controls with no major medical or mental health condition.
What does the study involve?
Participants will be recruited via community adverts and charities. Participants will take part in a single lab session where mild electrical pulses are applied to test pain perception. The capacity for pain modulation will be tested introducing a pain modulatory device. Participants will also complete questionnaires about pain, anxiety, and other psychological factors.
What are the possible benefits and risks of participating?
The study helps improve understanding of FND and pain perception. There are no direct health benefits for participants. The main risk is temporary discomfort from the mild electrical pulses.
Where is the study run from?
The study is conducted at the Institute of Psychiatry, Psychology & Neurosciences (IoPPN), King’s College London, UK
When is the study starting and how long will it run?
October 2024 to December 2025. The study will start recruiting in February 2025 and will be concluded by December 2025, or earlier, if the target sample of 80 participants is reached.
Who is funding the study?
The Felgenhauer Foundation for the Promotion of Young Neuroscientists (Felgenhauer Stiftung zur Förderung junger Neurowissenschaftler) and the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) fund the study. The study is carried out at King's College London.
Who is the main contact?
Dr. Livia Asan, Livia.Asan@kcl.ac.uk
Contact information
Public, Scientific, Principal Investigator
Institute of Psychiatry, Psychology and Neurosciences (IoPPN)
King's College London
16 De Crespigny Park
London
SE5 8AB
United Kingdom
 ORCID ID |
0000-0001-5813-3242 |
|---|---|
| Phone | +44 7440335811 |
| livia.asan@kcl.ac.uk |
Study information
| Study design | Mixed-methods controlled factorial-group study |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Non randomised study |
| Study setting(s) | Laboratory, University/medical school/dental school |
| Study type | Other |
| Participant information sheet | Not available in web format, please use the contact details to request a participant information sheet |
| Scientific title | Pain perception and its modulation in functional neurological disorder |
| Study acronym | FNDNO |
| Study objectives | This experimental study investigates the pathophysiologic mechanisms of functional neurological disorder and pain perception. |
| Ethics approval(s) |
Approved 12/12/2024, Health Faculties (Blue) Research Ethics Subcommittee of King's College London (3rd Floor, 5-11 Lavington Street, London, SE10NZ, United Kingdom; -; rec@kcl.ac.uk), ref: HR/DP-24/25-45681 |
| Health condition(s) or problem(s) studied | Functional neurological disorder |
| Intervention | This project employs a mixed, controlled, factorial group design with the between-subject factor group (functional neurological disorder (FND) versus non-clinical controls (NCC)) and the within-subject factors modulation condition (ON versus OFF). Target sample size N = 80, with n = 40 per group. Groups will be matched for sex, age, and, if possible, socioeconomic status. The experiment will include four phases. Experimental pain will be induced with mild electrical pulses (Digitimer, DS8R) and the effect of endogenous pain modulation will be tested by introducing a pain modulatory device. The modulation condition will be randomised at the trial level in phases 2-4 but there will be no experimenter blinding to group allocation (FND versus NCC). All participants will undergo the same experimental protocol. The pain stimulation trials in the different conditions (modulation ON versus OFF) in phases 2, 3 and 4 will be pseudo-randomised at the trial level. |
| Intervention type | Behavioural |
| Primary outcome measure | The following primary outcome measures are assessed using a Visual Analogue Scale (VAS) between 0-100 repetitively measured in the single lab visit during phases 2 and 4: 1. Pain intensity after each pain stimulus in each phase 2. Prior pain expectation at the beginning of each phase and again after every block of 4 pain stimuli within a phase 3. Prior pain expectation certainty at the beginning of each phase and again after every pain stimuli within a phase |
| Secondary outcome measures | The secondary outcome measures are all assessed during the single lab visit: The following outcomes are repetitively measured, once before phase 2 and once before phase 4: 1. Prior anxiety measured using a Visual Analogue Scale (VAS) between 0-100 at the beginning of each phase 2. Prior anxiety certainty measured using a Visual Analogue Scale (VAS) between 0-100 once at the beginning of each phase 3. State anxiety measured using the State-Trait Anxiety Inventory (STAI) (short 6-item-version: STAI-6) once at the beginning of each phase 4. Psychometric and health-related variables will be measured using the following questionnaires once in the single lab visit : 4.1. Functional Neurological Symptoms Questionnaire (FNSQ) 4.2. Brief illness perception questionnaire (B-IPQ) 6 4.3. Widespread Pain Index (WPI) 4.4. Pain Frequency Intensity and Burden Scale (P-FIBS) 4.5. Patient Health Questionnaire (PHQ-8) 4.6. Somatosensory amplification scale (SSAS) 4.7. Pain Vigilance and Awareness Questionnaire (PVAQ) 4.8. Generalized Anxiety Disorder (GAD-7 Anxiety) 13 4.9. Brief Autism-Spectrum Quotient, AQ-10+SM-4 4.10. Brief Dissociative Experience Scale (B-DES) 4.11. Fear of Pain Questionnaire – short (FPQ-9) 4.12. Pain Catastrophizing Scale (PCS) 4.13. Brief Suggestibility Scale (BSS) |
| Overall study start date | 01/10/2024 |
| Completion date | 31/12/2025 |
Eligibility
| Participant type(s) | Healthy volunteer, Patient |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 65 Years |
| Sex | Both |
| Target number of participants | 80 |
| Key inclusion criteria | For non-clinical (healthy) controls 1. Aged from 18-65 years old 2. Fluency in English to understand the study instructions For participants with lived experience of FND: 1. Aged from 18-65 years old 2. Fluency in English to understand the study instructions 3. Diagnosis of Functional Neurologic Disorder (FND) as defined in ICD-10 (FND with motor or sensory symptoms (ICD-10 F44.4 and 44.6), seizures (F44.5), or mixed symptoms (F44.7) or according to the diagnostic classification of DSM-5 |
| Key exclusion criteria | For all participants: 1. Diagnosis of major comorbid cardiovascular (e.g., heart disease) 2. Medical electrical implants, e.g., a pacemaker or implanted pumps, having implanted metals in the nondominant hand or arm, where the electrical pulses are applied 3. Pregnancy 4. Practical reasons against study participation: Physical symptoms / disability impairing ability to participate (e.g., severe/constant tremor, bilateral upper limb paralysis, multiple daily seizures) 5. Presence of a skin condition, scarring/tattoos on the left volar forearm at site of stimulation 6. Significant pain on the non-dominant volar forearm where pulses are to be applied during the 3 days before testing 7. Any aversion to receiving mild electrical pulses 8. Any aversion to experiencing pain during the experiment For non-clinical controls: To ensure the definition as non-clinical controls: Diagnosis of FND; active major physical or mental health disorder For participants with lived experience of FND: To minimize the risk of the experiment and avoid distortion on the physiological pain perception and/or would impair the ability to participate: active severe psychiatric disturbance (e.g., psychosis, alcohol, or substance dependence) or neurological (e.g., epilepsy, multiple sclerosis, Complex Regional Pain Syndrome (CRPS) in the tested arm) disorder that would either confound the findings or impair the participant’s ability to participate |
| Date of first enrolment | 20/02/2025 |
| Date of final enrolment | 31/12/2025 |
Locations
Countries of recruitment
- England
- United Kingdom
Study participating centre
London
SE5 8AB
United Kingdom
Sponsor information
University/education
Institute of Psychiatry, Psychology and Neurosciences
16 De Crespigny Park
London
SE5 8AB
England
United Kingdom
| Phone | +44 (0)20 7836 5454 |
|---|---|
| rgo@kcl.ac.uk | |
"ROR" |
https://ror.org/0220mzb33 |
Funders
Funder type
Government
Government organisation / National government
- Alternative name(s)
- German Research Association, German Research Foundation, DFG
- Location
- Germany
No information available
Results and Publications
| Intention to publish date | 31/12/2026 |
|---|---|
| Individual participant data (IPD) Intention to share | Yes |
| IPD sharing plan summary | Stored in publicly available repository |
| Publication and dissemination plan | Planned publication in a peer-reviewed journal |
| IPD sharing plan | The dataset generated during and/or analysed during the current study will be stored in a publicly available repository (Open Science Framework, OSF, https://osf.io/). • The type of data stored: Tabular data • Timing for availability: Data will be made available with the publication of the results in a peer-reviewed journal. No planned time limit for availability after publication. • Whether consent from participants was required and obtained: Consent for participation, including sharing of anonymised data on a public repository, will be collected. • Comments on data anonymization: All data will be anonymized, no sensitive and identifying data will be shared. |
Editorial Notes
03/03/2025: Internal review.
17/02/2025: Study's existence confirmed by the Health Faculties (Blue) Research Ethics Subcommittee of King's College London.
