Plain English Summary
Background and study aims
Conversion disorder (CD), also known as Functional Neurological Disorder (FND) is where neurological symptoms, such as weakness, occur but no structural neurological disease can be found – therefore they are disorders of function, rather than structure. There are few proven treatments for weakness that is caused by CD. There is encouraging preliminary evidence that Transcranial Magnetic Stimulation (TMS) could be an effective and safe treatment for such symptoms. This is a noninvasive procedure that uses magnetic fields to stimulate nerves in the brain. However, this treatment requires a randomization controlled trial to establish whether this is could be a treatment. The aim of this study is to examine if TMS can be a new treatment for CD.
Who can participate?
Adults aged 18 and older who have a motor conversion disorder.
What does the study involve?
Participants who are suitable for this study are randomly allocated to one of two groups. Those in the first group receive the active treatment and those in the second group receive in the inactive treatment. Participants attend two treatment sessions, separated by one month. Each TMS treatment session takes around 30 minutes. Some tests and questionnaires are completed before and after each TMS session, to assess current symptoms and health. In total, each treatment session will take around 1.5 hours. Two months after the first treatment session, participants are invited to attend a final follow-up session, during which several questionnaires and a short examination will be completed, but no additional TMS treatment will be delivered.
What are the possible benefits and risks of participating?
The main benefit to taking part is the potential to improve understanding about treatments that are effective for people with weakness caused by conversion disorder. There are some risks to taking part in the study as TMS can, in some cases, cause side effects including discomfort around the area it is delivered to (the scalp), headaches, and seizures. These side effects are relatively uncommon, particularly at low doses of TMS, such as that used in this trial. It is, however, also possible that some of the questionnaires might cause distress as they ask about psychological symptoms and potentially traumatic life events. Appropriate support will be provided to patients who disclose any significant distress or side effects during the study.
Where is the study run from?
King's College London (UK)
When is the study starting and how long is it expected to run for?
June 2014 to March 2018
Who is funding the study?
National Institute for Health Research (UK)
Who is the main contact?
Dr Tim Nicholson
Dr Tim Nicholson
King's College London
Section of Cognitive Neuropsychiatry (PO68)
Institute of Psychiatry Psychology & Neuroscience
De Crespigny Park
+44 207 848 5136
Trial Of Neurostimulation In Conversion Symptoms (TONICS) feasibility study
Transcranial Magnetic Stimulation (TMS) is more effective than placebo in improving weakness in motor conversion (functional neurological) disorder.
London - Stanmore Research Ethics Committee, 12/06/2017, ref: 17/LO/0410
Single-centre, single-blind, placebo-controlled parallel trial feasibility study
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
See additional files
Motor conversion (functional neurological) disorder
Participants are initially provided with a detailed information sheet and have time to consider participation and to ask questions. Once a patient has provided written informed consent, they attend an initial baseline appointment (approx. 1.5 hours) during which a research associate collects relevant background details about the patient (e.g., demographic details, psychological symptoms, medical history). A careful assessment of the safety of TMS for each individual is also completed during the baseline visit.
Patients diagnosed with motor conversion disorder (functional weakness of at least one limb) are randomised to one of two treatment arms using a computerised randomisation system. The treatment arms are active and inactive Transcranial Magnetic Stimulation (TMS). Both treatment arms involves single pulse TMS being delivered to primary motor cortex in both hemispheres. A total of 120 pulses are delivered during each of the two treatment sessions, which are one month apart. TMS is delivered by a suitably trained neurophysiologist or neuropsychiatrist. All TMS delivery takes in specialist TMS laboratories.
The aims are to investigate the feasibility of a trial of the above intervention.
Participants attend four sessions in total. One initial baseline assessment, two treatment sessions and a follow-up session. TMS session 1 takes place 0-14 days after baseline, TMS session 2 approximately one month after TMS session 1, and follow-up approximately three months after TMS session 1.
Primary outcome measure
Patient reported changes in symptoms measured using the patient-rated Clinical Global Impression of Improvement scale (CGI-I) at TMS session 1, TMS session 2 and at follow-up.
Secondary outcome measures
1. Assessor-rated symptom change measured using clinician-rated Clinical Global Impression of Improvement scale (CGI-I) at TMS session 1, TMS session 2 and follow-up
2. Disability and activities of daily living measured using functional rating scales: SF-36, Barthel, FIM/FAM at TMS session 1, TMS session 2 and follow-up
3. Current symptom severity measured using objective and subjective measures of strength: dynamometry and patient ratings at TMS session 1, TMS session 2 and follow-up
4. Current psychological symptoms measured using self-report questionnaires: GAD7, PHQ9, PHQ15 and CORE-10 at TMS session 1, TMS session 2 and at follow-up
5. Psychosocial outcomes measured with a self-report questionnaire: Work and Social Adjustment Scale at TMS session 1, TMS session 2 and at follow-up
6. Health economics measured using the Client Service Receipt Inventory at TMS session 1, TMS session 2 and at follow-up
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. DSM5 diagnosis of motor conversion disorder made by consultant neurologist and/or neuropsychiatrist, causing weakness of at least one limb
2. Age ≥18 years
3. Ability to give written informed consent
Target number of participants
Total final enrolment
Participant exclusion criteria
1. Epilepsy (or considered high risk of epilepsy from medical history)
2. Other contraindication to TMS (e.g. cochlear implants, metallic intracranial clips or intracranial surgery in last 12 months)
3. Comorbid organic neurological condition
4. Pain as primary symptom
5. Previous treatment with TMS (for any condition)
6. Non-fluent English speakers (if unable to accurately complete self-report questionnaires).
7. Major mental health disorder: current +/- previous diagnosis of schizophrenia or bipolar disorder; current drug/alcohol dependence
8. History of factitious disorder
9. Currently involved in another trial
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
King's College London
Neurophysiology Department Fourth floor Ruskin Wing King’s College Hospital Denmark Hill
National Institute for Health Research
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
The trial will be published in a high-impact peer-reviewed journal.
IPD Sharing statement:
Participant level data is not expected to be made available as it is not deemed necessary to do so for a feasibility study and we did not request ethical approval to publish these data. These data will be held at the host department (Section of Cognitive Neuropsychiatry, Institute of Psychiatry Psychology & Neuroscience, King’s College London).
Intention to publish date
Participant level data
Not expected to be available
Basic results (scientific)
2020 results in https://pubmed.ncbi.nlm.nih.gov/33028550/ (added 15/10/2020)
- ISRCTN51225587_PIS_V1_13Mar17.pdf Uploaded 02/10/2017