Netzwerk FNSFunctional Neurological Disorders · patient network

Home › Topics › Symptoms of FND

Understanding

Symptoms of FND – the most common forms

Functional Neurological Disorders can show themselves in very different ways – and often resemble other neurological conditions. This article gives an overview of which symptoms are typical.

“Symptom” in FND does not mean “imagined”. The complaints are real and often highly distressing. What connects the various forms: the symptoms often fluctuate (they can improve with distraction and intensify under tension), they can be positively recognised by typical clinical signs – and not infrequently several occur at once.1,2

The essentials

  • FND presents very differently – from paralysis through tremor to seizures.
  • The symptoms are real and often distressing, not “imagined”.
  • Typical is the variability: often better with distraction, stronger under stress.
  • The symptoms are positively recognisable (by clinical signs), not only by exclusion.
  • Several symptoms at once are common – that is typical, not contradictory.

Functional weakness & paralysis

An arm or leg feels heavy, powerless or “alien” – up to a paralysis that can resemble a stroke. Typical is that strength returns unexpectedly in certain situations (e.g. a functionally weakened leg extension that succeeds automatically as soon as the other leg becomes active – the Hoover’s sign). The movement is therefore in principle present, but not available on demand.1,3

Functional tremor & movement disorders

These include functional tremor, jerky twitches (myoclonus), cramped abnormal postures (functional dystonia) or tic-like movements. A hallmark of functional tremor: it changes when attention is distracted, and often “takes over” the rhythm of a given movement.2,3

Functional gait & standing disorders

Gait can appear unsteady, swaying, dragging or noticeably altered; some people need support or aids. Here too the variability is typical – the gait pattern can change markedly depending on the situation and attention.1

Dissociative (functional) seizures

Seizure-like states with changes in consciousness or movement that can resemble epileptic seizures but have no epileptic cause. They are frequently mistaken for epilepsy. How they arise and what helps is covered in detail in the article “Dissociation”.4

Functional sensory & visual disturbances

Possible are numbness, tingling or a furry feeling in body parts (functional sensory disturbance) as well as visual problems such as blurred vision, tunnel vision, double vision or a temporary deterioration of sight – without the eyes themselves being damaged.1,3

Functional speech & voice disorders

These include sudden stammering, an altered or whispering voice, slurred speech or a feeling of tightness in the throat. For this, too, there is targeted, specialised speech and language therapy.5

Functional cognitive disorders (“brain fog”)

Many people report concentration, word-finding and memory problems – the often-described “brain fog”. These complaints are real, but functional in nature: the capacity is in principle present, its retrieval is disturbed.2

Dissociation, depersonalisation & fatigue

Common companions are a feeling of unreality or “as if behind glass” (depersonalisation/derealisation) as well as pronounced exhaustion (fatigue). More on the theme of feeling detached is under “Dissociation”.6

What these symptoms have in common

As different as the forms are – three things hold for all: the symptoms are real, they are positively recognisable (not just an exclusion), and they are treatable. How the diagnosis is made is explained in the article “Causes & diagnosis”; which ways help is under “Treatment of FND”.1,4

UnderstandingCauses & diagnosis of FND → Read onTreatment of FND: what really helps →

Sources

  1. Espay AJ, Aybek S, Carson A, et al. Current Concepts in Diagnosis and Treatment of Functional Neurological Disorders. JAMA Neurology. 2018;75(9):1132–1141. doi:10.1001/jamaneurol.2018.1264. PMID 29868890.
  2. Hallett M, Aybek S, Dworetzky BA, et al. Functional neurological disorder: new subtypes and shared mechanisms. The Lancet Neurology. 2022;21(6):537–550. doi:10.1016/S1474-4422(21)00422-1. PMID 35430029.
  3. Aybek S, Perez DL. Diagnosis and management of functional neurological disorder. BMJ. 2022;376:o64. doi:10.1136/bmj.o64. PMID 35074803.
  4. Deutsche Gesellschaft für Neurologie (DGN). S2k guideline “Functional Movement Disorders”, AWMF register 030/148, 2026.
  5. Baker J, Barnett C, Cavalli L, et al. Management of functional communication, swallowing, cough and related disorders: consensus recommendations for speech and language therapy. J Neurol Neurosurg Psychiatry. 2021;92(10):1112–1125. doi:10.1136/jnnp-2021-326767. PMID 34210802.
  6. Stone J, et al. Functional neurological disorder – patient information. neurosymptoms.org (accessed 2026).

This overview does not replace a medical examination. Which symptoms are present in an individual case and how they are to be interpreted is clarified by FND-experienced clinicians.

← Back to home