Background and rationale for research
Functional neurological disorder (FND) is a common and debilitating condition accounting for between 5% and 16% of neurology outpatients and 8% of admission to acute stroke services.1,2 It includes a range of neurological symptoms, with specific clinical features of FND, including weakness, movement disorders, seizures, dizziness, sensory impairment and cognitive disorder.3 Alongside these core symptoms of FND, patients usually experience other physical and psychological symptoms, such as pain, fatigue and anxiety.4,5 This research is concerned with the motor symptoms of FND, which we refer to as functional motor disorder (FMD). Follow-up studies of FMD find that 80% of patients remain symptomatic in the long term, and for 40% of patients, the severity of symptoms remain unchanged or worsen over time.6 Persistent FMD symptoms are associated with high health and social care costs, unemployment and increased rates of lifestyle-associated illnesses.7–9
In recent years, the pathophysiology of FMD has been reconceptualised from simplistic psychological models to broad biopsychosocial frameworks. These recognise predisposing, precipitating and perpetuating factors, and seek to explain the mechanisms for how symptoms are produced and experienced as involuntary.10–12 Two important concepts in contemporary models of FMD are attention and expectation. With regard to attention, functional symptoms are exacerbated when the patient is attending to the symptom, and symptoms are attenuated or resolve when attention is externalised. This clinical observation forms the basis of many ‘rule-in’ signs used for diagnosis. Expectations, in this context, refers to a Bayesian predictive processing model for functional symptoms, where symptom-related beliefs or priors (top-down predictions) distort motor output and sensory (bottom-up) processing. Belief and predictions are not necessarily consciously reportable thoughts.
Although there is a long history of interventions for FMD,13,14 contemporary aetiological models for FMD have led to the development of novel approaches to treatment. For example, physiotherapy can aim to change maladaptive priors and retrain movement with redirected attention. A growing number of studies have explored the value of physical-based interventions for FMD,15–17 but there has been an absence of evidence from sufficiently powered randomised controlled trials (RCTs).
Leading up to the specialist physiotherapy for functional motor disorder (Physio4FMD) RCT, we developed a psychologically informed, physiotherapy treatment protocol for FMD, based on consensus recommendations.18 The intervention aims to address maladaptive beliefs about symptoms, retrain movement with redirected attention and address factors that may be working to maintain disability. The treatment approach was developed into a 5-day treatment protocol and tested in a cohort of 47 consecutive patients.19 The results were encouraging, with improved physical outcomes in the majority of participants at 3 months. Next, we conducted a randomised feasibility study which randomised 60 people with FMD to the specialist physiotherapy protocol or usual physiotherapy (community neurological physiotherapy).20 This study demonstrated the feasibility of conducting a powered RCT. At 6 months’ follow-up, there was a moderate to large difference between groups in a range of physical and quality-of-life outcome measures. The Physical Functioning domain of the Short Form questionnaire-36 items (SF-36) emerged as a suitable primary outcome for a powered trial. The Physio4FMD RCT commenced in May 2018.
Aims and objectives
We set out to determine the clinical and cost-effectiveness of a specialist physiotherapy intervention for FMD compared to treatment as usual (TAU), defined as community physiotherapy suitable for people with neurological symptoms. The primary objective was to determine the effectiveness of specialist physiotherapy compared to TAU in reducing disability, as measured by the SF-36 Physical Functioning domain at 12 months post randomisation.
The secondary objectives were to evaluate the effectiveness of specialist physiotherapy compared to TAU with regards to:
- the participant’s perception of change in their motor symptoms at 6 and 12 months
- mobility at 6 and 12 months
- health-related quality of life (HRQoL) at 6 and 12 months
- understanding of health condition and illness beliefs at 6 and 12 months
- anxiety and depression at 6 and 12 months
- health service utilisation at 12 months
- satisfaction with trial allocated treatment.
The primary aim of the health economic evaluation was to calculate the mean incremental cost per quality-adjusted life-year (QALY) gained with specialist physiotherapy compared to TAU over 12 months using the EuroQol-5 Dimensions, five-level version (EQ-5D-5L) questionnaire. The objectives were to evaluate specialist physiotherapy compared to TAU with regard to:
- cost-effectiveness from a health and social care perspective at 12 months
- cost-effectiveness from a societal perspective at 12 months
- continued employment or return to work at 12 months.