Synopsis
Make a positive rule-in diagnosis of functional weakness, movement, sensory or seizure symptoms, communicate it without stigma, identify comorbid neurological disease, and organise rehabilitation around retraining and self-management.
- Functional neurological disorder causes genuine motor, sensory, seizure, speech, gait or cognitive symptoms arising from altered nervous-system functioning rather than deliberate production.
- Diagnosis is positively supported by internal inconsistency and preserved automatic function, not by normal scans, psychiatric history, unusual affect or failure to find another disease.
- Hoover sign shows weak voluntary hip extension that improves when the opposite hip flexes against resistance, demonstrating preserved automatic motor recruitment.
- Functional tremor may change frequency, pause with distraction or entrain to a rhythm tapped by another limb, unlike a fixed pathological oscillation.
- Dissociative seizures are suggested by variable duration, fluctuating course, closed resistant eyes, asynchronous movement and preserved recall, but no single sign is fully diagnostic.
- Video EEG capturing a typical event is the diagnostic gold standard when epilepsy remains uncertain; frontal seizures and syncope can be difficult mimics.
- Psychological trauma or stress is neither necessary nor sufficient for diagnosis, although depression, anxiety, PTSD, pain, fatigue and adverse experiences can influence vulnerability and recovery.
- FND frequently coexists with migraine, epilepsy, Parkinson disease, multiple sclerosis, neuropathy or structural injury, so clinicians must identify which symptom belongs to which mechanism.
- Explain the diagnosis using the demonstrated positive sign, emphasise reversibility and provide a reputable written resource; simply saying tests are normal usually increases uncertainty.
- Specialist physiotherapy retrains automatic movement with redirected attention, while occupational, speech, psychological and seizure education address subtype and maintaining factors.
Key red flags
Persistent aphasia, true vascular field loss, new sphincter dysfunction, fever or objective progressive neurology requires urgent disease-specific assessment despite known FND.
Investigation priorities
Demonstrate inconsistency and preserved automatic motor capacity.
Management branches
New weakness, abnormal movement, gait or seizure-like activity presents urgently.
- Use the standard stroke, seizure, cord, metabolic or injury assessment appropriate to onset and objective findings, without allowing a previous FND label to lower safety.
- Once immediate threats are addressed, test validated inconsistency signs and document exactly what changes with automatic movement, distraction or entrainment.
- Seek neurological review when diagnosis remains uncertain or organic and functional components may coexist, avoiding repeated non-directed emergency investigations.
Key medicines
No core FND medicineThere is no medicine dose that directly corrects functional motor or seizure mechanisms; prescribe only for a defined comorbid symptom or diagnosis.Avoid escalating opioids, sedatives or antiseizure drugs for unconfirmed mechanisms; every continued medicine needs a target, benefit review and safe withdrawal plan.
Antiseizure medicine reviewWhen video EEG confirms only dissociative seizures, neurology designs a gradual agent-specific taper using the BNF rather than abrupt cessation.Some patients have both event types; abrupt withdrawal can provoke epileptic seizures, and driving advice must be based on all attacks and current DVLA rules.