A diagnosis of a Functional Neurological Disorder (FND) should be made by a Neurologist from positive signs and not just by purely eliminating commonly known physical causes.
However, with no national NICE guidelines on how to diagnose and treat people with functional neurological symptoms, in addition to the complexities surrounding the FND diagnosis generally, local and regional inconsistencies in diagnosis and treatment have occurred. This is unfair to both medical professionals and people who receive the diagnosis. This has resulted in some people having good care and some not so good, with a considerable amount of people complaining that they have been given the FND diagnosis, made to feel it is their fault, and no ongoing support. This has to change, and we at FND Action know that it is changing for some people, but we want it to change for everyone.
The FND diagnosis is given because a person is experiencing neurological symptoms which are not due to neurological disease, but due to problems with the functioning of the nervous system. Symptoms in many cases are disabling and it can take several years to receive the correct diagnosis.
How a diagnosis of a Functional Neurological Disorder is delivered can have a positive or detrimental effect on the person receiving the diagnosis, both with how they cope with the diagnosis and how and why they seek care.
Professor Edwards is a leading neurologist in functional neurological movement disorders and runs an out-patient clinic for patients with FND in London. In a recent article he discusses the importance of explaining to the patient what a diagnosis of FND means and what to do about it, and how failure to deliver the diagnosis correctly can impact on the therapeutic benefit of the consultation which is then lost. This in turn makes subsequent treatment more difficult.
Professor Edwards also makes it clear that focusing on the “how” rather than the “why” works for many patients and their recovery. He also states that “patients with functional neurological symptoms deserve a neurologist-led properly supported service which is flexible to their differing needs regarding treatment”
Depending on symptoms presented, the following tests/investigations are commonly used as part of investigating the diagnosis of functional neurological symptoms or other neurological conditions:
General medical examination, review of past history, and assessing presentation of symptoms
This should be performed at every initial appointment. A general medical examination is important to assess a person’s general health and wellbeing, and eliminate any other health conditions that may be present. It is important that the person has an understanding that other health issues, both physical or emotional, can play a part or be connected to functional neurological symptoms present.
CT (Computed Tomography) scan
An x-ray imaging test that provides detailed information on head injuries, stroke, brain tumours and other brain diseases. The examination involves you laying on a bed which slides into a ring shaped x-ray scanner.
MRI (Magnetic Resonance Imaging) scan
An imaging test that uses powerful magnets and radio waves to create pictures of the brain and surrounding nerve tissues, and used for the same purposes as a CT scan. As with a CT scan, you lay on a bed which slides in to the scanner, and creates more detailed pictures of tissues, organs and other structures within the body.
A test which is commonly used to diagnose functional weakness. This is a clinical test performed by painless touch and maneuvers.
A test used to help diagnose conditions such as seizures, epilepsy, head injuries, dizziness, headaches, brain tumours and sleeping problems. It is performed by attaching sensors to the scalp to pick up electrical signals produced in the brain.
We advocate that a blood test for vitamin deficiencies, especially B12, is undertaken as part of a diagnosis criteria if appropriate to symptoms, to ensure all potential other/contributing factors are considered.
For further information on how functional symptoms are diagnosed please visit neurosymptoms.org.
 Edwards, MJ. Functional neurological symptoms: welcome to the new normal Practical Neurology, 2016;16:2-3 doi:10.1136/practneurol-2015-001310
 Edwards, MJ. Mechanism of Functional Neurological Symptoms ACNR Clinical Review Article June 2013