FND subtypes
Functional neurological disorders are divided into five major subtypes, which share common aetiological and pathophysiological causes, but differ in the predominant symptoms and and consequently in the specificity of individual multidisciplinary management.
FND with sensory symptoms
The sensory form of functional neurological disorder includes sensory and visual symptoms and persistent postural sensory vertigo.
Functional seizures
Functional seizures are seizures similar to epilepsy, but with the difference that they are not caused by abnormal electrical activity in the brain, but by a process called dissociation.
Cognitive FND
Functional cognitive impairment refers to persistent and internally inconsistent cognitive symptoms that cannot be explained by any other neurodegenerative condition (Ball et al., 2020).
Functional speech disorder
Functional speech disorders are a subtype of functional neurological disorders and mimic the symptoms of organic speech disorders. Although any aspect of speech production can be affected, they most commonly manifest as dysphonia, stuttering or prosodic abnormalities (Duffy et al., 2016; Espay et al., 2018).