A Functional Neurological Disorder (FND) can encompass a diverse range of symptoms including limb weakness, paralysis, seizures, walking difficulties, spasms, twitching and more.
Whilst the symptoms may appear similar to those seen in neurological diseases such as Multiple Sclerosis, Parkinson’s and Epilepsy, and can be just as debilitating, they are not caused by structural disease of the nervous system. Instead, they are caused by a problem with the “functioning” of the nervous system.
The structure of the body is fine, but there is a problem with how the nervous system is functioning and how the brain fails to send and receive messages correctly. This impacts on how the body responds to different tasks such as movement control.
Perhaps the biggest misunderstanding of Functional Neurological Disorders is that somehow symptoms are under a patient’s control, and that there is always a psychological trauma (such as emotional memories following a distressful event) that has caused the symptoms.
Functional Neurological Disorders are often explained to patients as a psychological reaction 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.
A diagnosis can, and should be, made from positive neurological signs and tests that are specific to Functional Neurological Disorders. The Hoovers Sign, for example, is a specific test in relation to limb weakness. Whilst traditional MRIs cannot detect symptoms, research studies are beginning to provide evidence of grey matter abnormalities in the brain.
Functional neurological symptoms are commonly seen in Neurology and Epilepsy clinics, and in pediatric care. Disappointingly there are currently no national statistics to support this, so is based on limited regional reporting and patient feedback. These symptoms should not be classified under Medically Unexplained Symptoms (MUS).
Treatment for symptoms can overlap both Neurology and Psychology, and because of this it has led to many people ‘falling down a gap’ and left to fend by themselves, or has led to inadequate and inappropriate care. As understanding of Functional Neurological Disorders has advanced, so too has the debate among medical professionals regarding the diagnostic criteria and terminology.
Current understanding is that biological, psychological and social factors may contribute towards a person’s vulnerability to developing a Functional Neurological Disorder. Further research is needed to ascertain a clearer picture of the causes and mechanisms.
To learn more about Functional Neurological Disorders please visit the neurosymptoms website which is a key resource in the UK and worldwide, and is written by a leading specialist in this field.
CLICK HERE for information about symptoms.
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 Carine W. Maurer, Katrin Lafaver, Gaurang S. Limachia, Geanna Capitan, Rezvan Ameli, Stephen Sinclair, Steven A. Epstein, Mark Hallett, Silvina G. Horovitz. Gray matter differences in patients with functional movement disorders. Neurology Nov 2018, 91 (20) e1870-e1879; DOI:10.1212/WNL.0000000000006514
 Stone J, Hallett M, Carson A, Bergen D, Shakir R. Functional disorders in the Neurology section of ICD-11. A landmark opportunity Neurology. 2014;83(24):2299–2301. doi:10.1212/WNL.00000000000010633