Loss and Return of Ticklishness in Functional Neurological Disorder

BackgroundPeople with functional neurological disorder (FND) have abnormalities in sensory processing. Loss of ticklishness has been rarely reported.ObjectivesTo describe associated clinical features in people with FND and loss of ticklishness and explore correlations with sensory changes.MethodsRetrospective audit of clinical letters of people diagnosed with FND in a tertiary clinic and further cases identified in a general neurology clinic.ResultsThirty-eight patients with loss of ticklishness are described, of which most had other functional sensory symptoms and signs. It was more often localized to one limb, rather than generalized, in those with pain or weakness. Dissociation for the affected body part was often described.ConclusionsLoss of ticklishness in FND is frequently described and offers insights into mechanisms of agency, sensory processing and interoception, which are known to be altered in FND.