What is functional neurologic disorder?
Functional neurologic disorder (FND) refers to a neurological condition caused by changes in how brain networks work, rather than changes in the structure of the brain itself, as seen in many other neurological disorders. Physical symptoms of FND are genuine but cannot be explained by changes in the brain structure. The exact cause of FND is unknown.
FND symptoms may include:
- Seizure-like episodes
- Movement problems
- Problems with cognitive function
- Dizziness
- Speech difficulties, such as sudden onset of stuttering or trouble speaking
- Problems with vision or hearing
- Pain (including chronic migraine)
- Extreme slowness and fatigue
- Numbness or inability to sense touch
FND can cause multiple symptoms that significantly interfere with how a person functions and copes with daily life. Symptoms of FND are not intentionally produced and can involve any part of the body. Symptoms may appear suddenly, increase with attention to them, and decrease when the person is distracted.
Brain imaging (like MRI and CT scans) and other neurological tests are often normal in a person with FND. However, research studies that have used functional neuroimaging and neurophysiology (both of which focus on how the brain works rather than what it looks like) have demonstrated changes in that the connections between different regions of the brain in people with FND. In FND, the brain is unable to send and receive signals properly. Additionally, the sense of agency or that one is controlling one’s own actions, is impaired. Many research studies have showed that people with FND have increased activity in limbic system, which deals with emotions and behaviors, resulting in problems with regulating emotion and responding to stress.
There are many types of FND, with a diverse mix and range of neurologic symptoms. For some people, symptoms are short-lived. In others, they may last for years.
The two most common categories of FND are functional or dissociative seizures (also known as psychogenic nonepileptic seizures (PNES), and functional movement disorder.
Functional or dissociative seizures
Functional or dissociative seizures cause seizure-like episodes that are not due to abnormal electrical signaling in the brain. The person may have episodes of movement, sensation, and behavior similar to a seizure and may have a temporary loss of attention or memory. The person may also be confused or experience a loss of attention (without shaking). The person might feel “disassociated” (or disconnected) from their thoughts or feelings or from the environment.
Symptoms that are associated with function/dissociative seizures may include:
- Eye closure during the episode
- Side-to-side head movement
- Pelvic thrusting
- Prolonged attacks
- Hyperventilation
- Shaking all over the body (with awareness)
Functional movement disorder
Functional movement disorder affects how the body moves. Any type of abnormal movement can be seen in functional movement disorder. About half of the time, people with the disorder experience more than one type of abnormal movement. Symptoms may include:
- Tremor
- Sudden, brief involuntary twitching or jerking of a muscle or group of muscles (myoclonus)
- Involuntary muscle contractions that cause slow repetitive movements or abnormal postures (dystonia)
- Problems with walking (gait), posture, or balance
- Muscle spasms and stiffness
- Tics
- Leg and arm weakness or paralysis
FND can be difficult to understand for the person with the disorder, their family and friends, and their healthcare team. Physicians may wrongly consider symptoms of FND as feigning or faking, which can leave patients feeling stigmatized. Early diagnosis and treatment can help lessen symptoms and aid in healing.
Who is more likely to get functional neurologic disorder?
Anyone can develop FND. It is more common in women and can affect both children and adults. Most people with functional movement disorders begin to have symptoms around their late 30s. Symptoms of functional seizures most often begin in a person’s late 20s. The fundamental of FND involve biological and sociological factors. While risk factors in adults include exposure to psychological stressors and a history of childhood adversity, those factors are not seen in all people with FND. In children, risk factors can include family problems, bullying, perceived peer pressure, and abuse. It is common for people with FND to also have depression, anxiety, or post-traumatic stress disorder. Some studies suggest that genetic or environmental factors may affect a person’s risk.
How is functional neurologic disorder diagnosed and treated?
Diagnosing FND
There is no single test or biomarker (biological sign of disease) to confirm the diagnosis of FND. Diagnosis of FND is made based on the person’s history, symptoms, and a physical exam. There are some signals that indicate FND, including Hoover’s sign (a physical test to identify functional weakness in the legs), and what’s called “entrainment” for tremor. Entrainment involves moving the unaffected or less affected limb at a certain rhythm to see if the limb experiencing tremor responds. A doctor will assess the person’s health, family history, and medical history to rule out any neurological or other conditions that may cause symptoms. FND can co-exist with other disorders. The healthcare team will look for specific triggers and patterns of symptoms to help make a diagnosis.
Doctors may order tests, which can include imaging scans like EEG (electroencephalography, which monitors the brain’s electrical activity), or EMG (electromyography, which records the electrical activity in muscles). These can help rule out other disorders and examine symptoms such as tremor, weakness, walking trouble, and vision problems.
Treating FND
Strong, two-way communication between the healthcare provider and the patient is important for effective treatment of FND. This will help improve the patient’s understanding of the disorder and involve them actively in their own treatment. A team of doctors and health professionals from various specialties should work together with the individual to deliver a combination of treatments and comprehensive care. Currently, the two main treatment approaches include physical therapy and psychotherapy. Medications may help with certain symptoms.
- Psychotherapy: Psychotherapy involves talking with a licensed and trained mental health professional about negative or troublesome emotions, behaviors, and thoughts. Cognitive behavior therapy (CBT) can help a person modify their thought patterns to change emotions, mood, or behavior. Psychodynamic therapy can help people identify and resolve patterns in thoughts, beliefs, and emotions that may cause some of the neurological symptoms. Relaxation and mindfulness exercises can help reduce stress. Some individuals benefit from hypnosis to induce relaxation and lessen FND symptoms.
- Medications: Medications are available to treat pain, anxiety, depression, insomnia, and headache that may occur with FND. People with functional seizures should not take anti-seizure medications. Anti-seizure medications do not treat as functional symptoms like they do epileptic seizures and might even worsen the symptoms.
- Other treatments: Some studies of transcranial magnetic stimulation (TMS), which uses magnetic fields generated outside the skull to stimulate nerve cells in the brain, have shown promise, although results have been mixed. Transcutaneous electrical stimulation (TENS), which uses low-voltage noninvasive electrical current to activate nerves, can be useful for relieving certain pain in people with FND.
People with functional or dissociative seizures should try to identify warning signs and learn techniques to avoid harm or injury during and after the seizure. Be aware that relapses and flare-ups often recur, despite treatment.
What are the latest updates on functional neurologic disorder?
NINDS, a component of NIH, the leading supporter of biomedical research in the world, is the primary federal funder of research on neurological disorders. Scientists funded by the NIH are working to better understand the underlying neurobiology and pathophysiology of FND using MRI (magnetic resonance imaging) to develop neuroimaging biomarkers—biological signs of disease that can be used for diagnosis, risk assessment, or to monitor progression—for FND. Among other research, investigators hope to develop a test to diagnose and better treat FND.
How can I or my loved one help improve care for people with functional neurologic disorder?
Consider participating in a clinical trial so clinicians and scientists can learn more about FND and related disorders. Clinical research with clinical participants to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.
All types of human participants are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.
For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with FND at Clinicaltrials.gov.
Where can I find more information about functional neurologic disorder?
Information may be available from the following resources:
Functional Neurological Disorders Society
(For physicians and researchers)