Researchers
Dr Jon Stone – Research Fellow in Neurology
Dr Michael Sharpe – Reader in Psychological Medicine
Professor Ian Deary – Professor of Differential Psychology
Professor Charles Warlow – Professor of Neurology
- all of The University of Edinburgh
Aims
Functional (or medically unexplained) motor symptoms are symptoms such as weakness, tremor and inability to walk that are real but are not due to a measurable structural disorder of the nervous system.
We wanted to find out: How common are these symptoms? How disabling and distressing are they? And can we test which factors are associated with a view to learning more about the cause?
Project Outline/Methodology
We used a survey and case control design. Patients with functional motor symptoms of less than two years duration, were identified by referred from neurologists in South East Scotland. These cases were then compared with two control groups. One had weakness caused by a neurological disease (predominantly multiple sclerosis) and the other was of healthy patients attending their GP.
We first estimated the minimum number of cases in south East Scotland (minimum because not all cases will be referred to neurology). We then compared the distress, disability and a number of possible casual factors between cases and controls.
Key Results
We recruited 107 patients (and 85 controls) with recent onset functional motor symptoms over 2.5 years. All had weakness or paralysis of a limb. This indicates a minimum incidence (new cases) of around five cases per 100,000 per year in South East Scotland which is similar to the incidence of multiple sclerosis.
In comparison to controls, cases were just as disabled but had more symptoms, particularly pain (p<0.0001), and were twice as likely to be not working (59% vs 29%, p<0.001) .
Cases were more likely to:
- suffer from depression (32% vs 7%, p<0.001) and panic (36% vs 13%, p<0.01)
- report adverse childhood experience (38% vs 18%. P<0.005)
- disagree that stress was a cause for symptoms (60% vs 21%, p<0.0005)
- be dissatisfied with the care they had received from doctors (p<0.001)
Analysis of detailed data on recent ‘stresses’ ( life events) is ongoing.
In many patients the functional symptoms came on after a physical injury (14%) or an attack resembling panic (36%) often in association with a feeling called depersonalisation. Another group of patients developed weakness slowly during an illlness characterised by fatigue
Conclusions
Functional motor symptoms are as common as multiple sclerosis and just as distressing and disabling. The cause probably varies greatly between patients. A combination of personal vulnerability combined with a physical injury, an unexpected episode of depersonalisation or an illness characterised by fatigue may be important in bringing these symptoms on.
What does this study add to the field?
This is the largest ever study of this type of problem. It adds new data in a number of areas and will form the basis of a follow up study to measure outcome and its predictors and to inform treatments.
Implications for Practice or Policy
Doctors tend to dismiss these symptoms as being rare or ‘not serious’. These problems are common disabling and distressing.
Where to next?
A follow up study of this cohort; more
work on improving communication between
doctors and patients about these
symptoms, investigations of the
functional changes within the brain,
a follow up study and treatment trials.
Further details from: Dr Jon Stone