Measurement of symptom severity, disability and distress associated with functional motor disorder
Currently there are few outcome measures that have been validated for FMD, and there is insufficient data to determine which assessment tools are most useful for research.55 The discrepancy found in the current study between the SF-36 Physical Functioning, and patient perception of change, suggests that the SF-36 Physical Functioning score may miss important changes associated with specialist physiotherapy. We did not include an in-person assessment of motor symptom severity (e.g. the Simplified Functional Movement Disorders Rating Scale) due to cost limitations, and this may have been a better primary outcome or provided additional information as a secondary outcome.53 Future research should explore the use of modern technology to develop more objective outcome measures for FMD, such as wearable mobility trackers, that can account for symptom variability over time.
Patient selection and refining the intervention
Future research is needed to identify who benefits most from specialist physiotherapy for FMD and what alternative or additional treatments are needed. This work may include identifying which components of specialist physiotherapy are most important and optimal dose.
What is the cost of illness and what are the cost benefits of interventions for functional motor disorder?
We found a high cost of illness and high probability that specialist physiotherapy was cost-effective in those meeting the eligibility criteria. Research specifically designed and powered for economic evaluation involving broader eligibility criteria is needed. Considering that people with FMD often experience delays in diagnosis and exclusion from treatment (e.g. the mean symptom duration in participants of the current study was 4.8 years), it is likely that there are opportunities to reduce costs, and early intervention may prove to be even more cost effective.
What is the most effective treatment for children and young people with functional motor disorder?
The incidence rate of FMD in children is similar to that of adults, and a recent study found that prognosis is often poor.56 Yet research and evidence for treatment of FMD in children is scarce and therefore should be a priority for research. Similarly, there are little data on how treatment may need to be adapted to meet the needs of people from different cultural backgrounds, and this should be explored in future research.