Functional laryngeal dyskinesia: an important cause of stridor.

Functional laryngeal dyskinesia is a disorder that presents with stridor. Failure to recognize its features can result in inappropriate investigation and treatment for a condition that has a psychogenic origin. The key feature in diagnosis is paradoxical vocal fold adduction on inspiration, as seen on fibre-optic nasendoscopy. This phenomenon together with the associated stridor may disappear after distraction techniques or when the patient is asleep. We present five such cases which presented to hospitals in south west London over a 12 month period.