Functional Neurological Disorder (FND) encompasses a diverse range of symptoms including functional limb weakness and movement disorders, functional and dissociative attacks (non epileptic), sensory problems, cognitive problems, visual and speech symptoms. Whilst the symptoms may appear similar to neurological diseases including those of Multiple Sclerosis, Parkinson’s and Epilepsy, and can be just as debilitating, they are not caused by structural disease of the nervous system, but 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, for example, movement control. The Hoovers Sign, which is a specific test with regards to functional limb weakness, illustrates this response as a positive physical sign. Whilst traditional MRIs cannot detect functional symptoms and patients are confused with a “clear” brain scan, research studies using functional MRIs are beginning to produce evidence of the differences occurring in the brains of people with FND.
FND is a complex but common condition. It overlaps both neurology and psychology and this is reflected in the confusing array of terminology that has developed to explain functional symptoms. As understanding of functional neurological symptoms has advanced, so has the debate amongst medical professionals regarding the diagnostic criteria and terminology as can be seen with reference to the 11th revision of the World Health Organisation’s International Classification of Diseases (ICD-11).
Historically, past trauma was thought to be the only factor that influenced the development of functional neurological symptoms, but research findings indicated this was not the case for everyone with an FND diagnosis. FND is the term most frequently used in the UK for functional symptoms, and the current understanding is that a combination of physical, psychological and social factors may contribute towards a person’s vulnerability to developing FND.
To learn more about FND please visit the neurosymptoms website which is a key resource for those interested in FND both here in the UK and elsewhere.
 Stone, J. neurosymptoms.org. Available at “www.neurosymptoms.org” [accessed 28th August 2016].
 Healthcare Improvement Scotland Stepped care for functional neurological symptoms. A new approach to improving outcomes for a common neurological problem in Scotland Report and recommendations February 2012 [Accessed 28th August 2016]
 Talin, J. It Is All in Their Head: Functional MRI identifies Neural Abnormalities in Patients with Functional Movement Disorders. Neurology Today 2016; 16(14)-pp1,12-14
 Stone. J, Hallett M, Carsen. A, Bergen. D, Shakir, R. Functional disorders in the Neurology section of ICD-11. A landmark opportunity NCBI The Official Journal of the American Academy of Neurology, 2014 Dec 9, 83(24): 2299-2301