FND Awareness Day: All About Functional Neurological Disorder (FND)
Functional Neurological Disorder (FND) is a medical condition which is typically associated with a problem with the functioning of the nervous system. It affects the functional connectivity in certain parts of the brain, which includes controlling of muscles and senses. FND includes a wide variety of neurological symptoms, like- limb weakness or seizures, paralysis, speech problems, etc.FND is a condition at the intersection of the specialties of neurology and psychiatry. Typical tests like MRI brain scans and EEGs are generally done on the patients with FND, as it gives the detailed insight into the brain and helps in spotting the abnormalities. FND is a common cause of disability and distress, which may coexist with problems such as chronic pain and fatigue. Customised specific treatments of FND can help the patients recover quickly.
Earlier people considered FND as, ‘all psychological’ and that the diagnosis is made only when a person’s tests results are normal. However, the mentality has changed since the mid-2000s. Recent neuroscientific studies, have shown that FND is not a diagnosis of exclusion. It carries specific clinical features of its own and is considered a disorder of the nervous system functioning. Symptoms may differ; in some people, psychological factors are eminent, while in others they are not.
What are the signs and symptoms of FND?
FND patients can experience a vast range and combination of symptoms that are physical, sensory and/or cognitive. The most common ones are:
- Motor dysfunction:
- Functional limb weakness/paralysis.
- Functional movement disorders like tremors, jerky movements, spasms (dystonia), (myoclonus) and gait disorder.
- Functional speech symptoms like dysphonia, slurred or stuttering speech.
2. Sensory dysfunction:
- Functional sensory disturbance includes altered sensation like numbness, tingling or pain in the face, torso or limbs.
- Functional visual symptoms like vision loss or double vision.
3. Episodes of altered awareness:
- Dissociative (non-epileptic) seizures
What are the causes of FND?
The exact cause of FND is not known. Number of different predisposing factors can make patients more vulnerable to FND, which includes chronic pain, fatigue or stress. However, some people with FND experience none of these risk factors.
At the time FND begins, according to studies, there may be triggering factors like a physical injury, infectious illness, panic attack or migraine which can give someone the first experience of the symptoms. These symptoms usually settle down on their own. However, in FND the symptoms become ‘stuck’ in a ‘pattern’ in the nervous system. That ‘pattern’ is mirrored in altered brain functioning. This results into a genuine and disabling problem, which the patient cannot regulate in any way. The aim of treatment is to mainly ‘retrain the brain’; for example, by unlearning abnormal and dysfunctional movement patterns that have been developed and relearning all the normal movements.
MRI brain scans are usually normal in FND. Functional brain scans (MRI) have started displaying early evidence for how the brain goes wrong in FND. MRI scans show changes in patients with FND, which look quite different from healthy patients without these symptoms, as well as healthy people ‘pretending’ to have these symptoms.
Psychological disorders and disturbing life events, both recent and experienced in childhood, may act as risk factors for developing the condition in some patients. However, they rarely provide a full explanation for the cause of the condition and are not present in many patients. A patient does not have to be depressed, anxious or the survivor of adverse childhood experience to develop FND.
FND can affect anyone, at any time, although it is not common in children under 10 years of age. FND is more likely to affect women than men for most symptoms, although it occurs equally in both groups in patients over the age of 50.
How is FND diagnosed?
FND is diagnosed on the basis of positive physical signs, and usually requires the support of a neurologist.
- Hoover’s test is performed for functional leg weakness – the patient may find it difficult to push their ‘bad’ leg down (hip extension), but on being asked to lift up their ‘good’ leg, movement in ‘bad’ leg returns transiently to normal.
- The tremor entrainment test is performed for functional tremor – this is when the shaking of an arm or leg becomes temporarily better, when the person focuses on copying a movement that the examiner makes.
How is FND treated?
FND can be difficult to understand and most people haven’t heard of it. Treatment should begin with an understandable and supportive explanation of the positive clinical features that have allowed the diagnosis to be made, even though scans and other laboratory tests may be normal.
This therapy is for patients with motor symptoms such as limb weakness, gait problems or movement disorder. Physical therapy from a therapist who understands something of FND can be helpful.
Physiotherapy designed specifically for FND can be helpful for some patients.
Cognitive-Behavioural Therapy (CBT) is generally the first line of treatment for patients with dissociative (non-epileptic) seizures or attacks as part of their FND and is supported by clinical trials. Therapy includes learning and understanding more about the attacks and recognising brief warning symptoms and learning techniques to regain control. For some patients it is of great help to look more widely at thoughts, emotions, and experiences that could have played a role in the development of symptoms. Psychological therapy is helpful in getting confidence back. FND itself is often experienced as a stressful condition to manage and live with.
Occupational Therapy assists patients in finding adaptations and gaining confidence back, as far as their ability to carry out daily activities at home or workplace, is concerned. Occupational therapy can help build on other therapies to contribute to a better overall quality of life.
Speech therapy is an important part of treatment for people diagnosed with FND. There are patients who experience complete loss of ability to speak after a head injury or stroke. In such cases, speech therapy helps with regard their ability to speak smoothly.
Dr Madhusudhan B K is Senior Consultant, Neurologist and Epileptologist at BGS Gleneagles Global Hospital, Bengaluru.