Functional neurological disorder

Overview and approach

FND is diagnosed using positive clinical features, not merely because tests are normal; symptoms are real and involuntary.

FND is diagnosed by positive clinical findings (symptoms that fluctuate with attention or effort, or are inconsistent with recognised neurological patterns), not by excluding other conditions (1)(2).

Assessment and clinical features

Assess symptom pattern, positive examination signs, function and coexisting neurological or mental health disease.

Hoover sign supports functional leg weakness: apparent hip-extensor weakness resolves when the patient flexes the opposite hip against resistance (1)(2).

Differentials and investigations

Use targeted tests to address plausible alternatives; specialist assessment supports a clear positive diagnosis.

Investigate enough to exclude plausible alternatives (e.g. MS, stroke, epilepsy, myasthenia) but avoid repeated testing once a positive diagnosis is clear.

Management and follow-up

Explain the diagnosis respectfully and offer multidisciplinary rehabilitation and psychological support when useful.

Explain that the nervous system is not damaged but is not functioning normally, validate that symptoms are real and address fears of MS or tumour (2)(3).
In Australia, physiotherapy with goal-oriented movement retraining, education, distraction, pacing and relapse prevention is appropriate for functional movement symptoms (1)(4); add psychological support where useful.

Red flags and clinical pearls

FND and structural disease can coexist. Reassess genuinely new focal signs, seizures or major deterioration rather than dismissing them.

Functional symptoms can coexist with structural disease or epilepsy, so reassess new objective signs (5).

References