What is Functional Neurological Disorder
Functional Neurological Disorder (FND) is a brain network disorder that can encompass a diverse range of neurological symptoms including limb weakness, paralysis, seizures, walking difficulties, spasms, twitching, sensory issues and more. Anyone of any age can receive the diagnosis. For many symptoms are severe and disabling, and life changing for all.
Whilst the symptoms may appear similar to those seen in neurological conditions such as Multiple Sclerosis, Parkinson’s and Epilepsy, and can be just as debilitating, they have a different underlining cause.
The basic wiring of the nervous system is intact, but there is a problem with how the brain/nervous system is “functioning”, and how the brain fails to send and/or receive signals (messages) correctly. This impacts on how the body responds to different tasks such as movement control and attention.
“Functional Neurological Disorder is often explained to patients as a psychological reaction due to past trauma, or as symptoms due to stress. These explanations usually fail and result in patients feeling alienated, stigmatised and not-believed. The main reason for the failure of such explanations is that they take a potential risk factor and turn it into the cause of the problem.”
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A diagnosis is made by a Neurologist from positive neurological signs and tests that are specific to Functional Neurological Disorders. The Hoover’s Sign, for example, is a specific test in relation to limb weakness. It is important a positive diagnosis is reached to avoid misdiagnosis, and that consideration is given to the fact that FND may also present alongside other Neurological diseases.
Throughout history, a lack of understanding of FND has led to people being dismissed, neglected or not believed. To this day this is still happening across the UK, and below are some FND myths sourced from the consensus paper A practical review of functional neurological disorder (FND) for the general physician, written by some of the leading specialists in the field.
The diagnosis of FND should be ‘ruled in’ based on the presence of positive signs.
FND commonly co-occurs with other neurological conditions.
A bizarre presentation does not equate to a diagnosis of FND. Unusual presentations can occur with other neurological conditions.
Shared mechanisms and comorbidities, such as pain and fatigue, may be present between patients with FND.
FND symptoms are involuntary. Patients are not ‘putting them on’ as have no form of control. Feigning is very rare.
Investigations can be useful to identify comorbid neurological conditions. Other neurological conditions are a strong risk factor for FND.
FND is not misdiagnosed more than other conditions. Erroneously diagnosing FND as another neurological condition can be as harmful as the reverse.
Psychological factors are one of many possible risk factors for FND and should not be considered the sole aetiological cause.
Patients with FND are as disabled, and have as impaired quality of life, as patients with other neurological conditions.
FND treatment is individualised and multidisciplinary, involving combinations of physical and psychological rehabilitation.
Further reading: Lidstone SC, Araújo R, Stone J, Bloem BR. Ten myths about functional neurological disorder. Eur J Neurol. 2020 Nov;27(11):e62-e64. doi: 10.1111/ene.14310. Epub 2020 Jun 4. PMID: 32400011.
Functional neurological symptoms are commonly seen in Neurology and Epilepsy clinics, and in pediatric care. Studies suggest symptoms are the second most common reason for an initial Neurology appointment, after headaches/migraines that require further investigation. Symptoms are sometimes referred to as Medically Unexplained (MUS). This is inappropriate given it is known that there is a problem with how the nervous system is functioning, so being referred to in this way is misleading for those diagnosed and clinicians.
Current understanding is that biological, psychological and social factors may contribute towards a person’s vulnerability to developing a Functional Neurological Disorder. Research continues to ascertain a clearer picture of the causes and mechanisms.
To learn more about Functional Neurological Disorder please visit the neurosymptoms website which is a key medical information resource in the UK and worldwide, and is managed by a leading specialist in this field.