Functional Neurologic Disorder (FND) is a condition related to the nervous system where patients experience neurological symptoms, such as weakness, movement disorders, sensory symptoms and attacks. It’s caused by a problem with how the brain functions, rather than damage to the brain’s structure itself. This means that while brain scans like MRI may appear normal, there’s a disruption in the brain’s communication networks. The precise cause of FND is currently unknown, but it’s an area of active research.
FND can manifest in a variety of ways, impacting a person’s ability to function daily. The symptoms are real and not intentionally produced by the individual. These symptoms can include:
- Seizure-like episodes (Functional or Dissociative Seizures)
- Movement problems (Functional Movement Disorder)
- Cognitive difficulties
- Dizziness
- Speech problems (stuttering or difficulty speaking)
- Vision or hearing issues
- Pain, including chronic migraines
- Extreme fatigue and slowness
- Numbness or sensory changes
These symptoms can fluctuate, worsen with attention, and improve with distraction. It’s important to recognize that FND is a complex condition requiring a comprehensive understanding and approach.
Brain imaging techniques, such as MRI and CT scans, often appear normal in individuals with FND. However, advanced neuroimaging and neurophysiological studies reveal alterations in the connectivity and function of different brain regions. These studies suggest that in FND, the brain struggles to process and transmit signals correctly. The sense of agency, the feeling of control over one’s own actions, may also be impaired. Research indicates heightened activity in the limbic system, which is responsible for emotions and behaviors, leading to challenges in emotion regulation and stress response.
The experience of FND varies widely. Symptoms can be transient for some, while others may face chronic challenges spanning years. Two common categories of FND are functional seizures and functional movement disorders.
Functional or Dissociative Seizures (Psychogenic Nonepileptic Seizures – PNES)
Functional seizures, also known as dissociative seizures or psychogenic nonepileptic seizures (PNES), mimic epileptic seizures but are not caused by abnormal electrical activity in the brain. Individuals may experience movements, sensations, and behaviors resembling seizures, potentially including temporary loss of awareness or memory. Confusion or a sense of detachment from thoughts, feelings, or the surrounding environment can also occur.
Common symptoms associated with functional seizures include:
- Eye closure during the episode
- Side-to-side head movements
- Pelvic thrusting
- Prolonged attacks
- Hyperventilation
- Shaking with retained awareness
Functional Movement Disorder
Functional movement disorder affects a person’s ability to control their movements. A wide array of abnormal movements can occur, and many individuals experience multiple types of movement abnormalities. Symptoms may include:
- Tremors
- Myoclonus (sudden, brief muscle jerks or twitches)
- Dystonia (involuntary muscle contractions causing repetitive movements or abnormal postures)
- Gait abnormalities (problems with walking, balance, or posture)
- Muscle spasms and stiffness
- Tics
- Weakness or paralysis in the arms or legs
Understanding FND can be challenging for patients, families, and healthcare providers. It is essential to differentiate FND symptoms from malingering. Misunderstanding can lead to stigma and delayed access to appropriate care. Timely diagnosis and treatment are crucial for managing symptoms and promoting recovery.
Who is at Risk for Functional Neurologic Disorder?
FND can affect anyone, regardless of age or background. It is more frequently diagnosed in women. While functional movement disorders often manifest in the late 30s, functional seizures tend to emerge in the late 20s. The development of FND involves a complex interplay of biological, psychological, and social factors. While psychological stressors and childhood adversity are recognized risk factors in adults, they are not universally present in all FND cases. In children, family issues, bullying, peer pressure, and abuse can contribute to the risk. Co-occurring conditions such as depression, anxiety, and post-traumatic stress disorder are common in individuals with FND. Research also suggests that genetic and environmental factors may play a role in an individual’s susceptibility to FND.
Diagnosis and Treatment of Functional Neurologic Disorder
Diagnosing FND
Currently, there is no single test or biomarker to definitively diagnose FND. The diagnosis relies on a comprehensive evaluation of a person’s medical history, symptoms, and a thorough physical examination. Certain clinical signs, such as Hoover’s sign (a test for functional leg weakness) and entrainment (observing the response of a tremor to rhythmic movements), can support the diagnosis. A doctor will carefully assess the person’s overall health, family history, and medical history to rule out other neurological or medical conditions that could be responsible for the symptoms. It is important to note that FND can coexist with other medical conditions. The healthcare team will identify specific patterns and triggers of symptoms to aid in the diagnostic process.
Diagnostic tests, including EEG (electroencephalography) to monitor brain electrical activity and EMG (electromyography) to record muscle electrical activity, may be ordered to exclude other conditions and investigate symptoms like tremor, weakness, gait disturbances, and vision problems.
Treating FND
Effective FND treatment hinges on strong communication between the healthcare provider and the patient, fostering understanding and active participation in the treatment plan. A multidisciplinary team of doctors and allied health professionals should collaborate to deliver tailored treatments and comprehensive care. The primary treatment approaches are physical therapy and psychotherapy. Medications may be used to manage specific symptoms.
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Psychotherapy: This involves working with a qualified mental health professional to address challenging emotions, behaviors, and thoughts. Cognitive Behavioral Therapy (CBT) can help modify thought patterns to improve emotions, mood, and behavior. Psychodynamic therapy can help individuals identify and resolve underlying patterns of thoughts, beliefs, and emotions that contribute to neurological symptoms. Relaxation and mindfulness techniques can also be beneficial for stress reduction. Some individuals may benefit from hypnosis to promote relaxation and reduce FND symptoms.
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Medications: While there is no specific medication for FND, medications can address related symptoms such as pain, anxiety, depression, insomnia, and headache. It is important to emphasize that anti-seizure medications are not effective for functional seizures and may even worsen symptoms.
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Other treatments: Studies on transcranial magnetic stimulation (TMS), a noninvasive brain stimulation technique, have shown some promise in treating FND, although results vary. Transcutaneous electrical nerve stimulation (TENS), which uses low-voltage electrical current to stimulate nerves, may be helpful for pain relief in some individuals with FND.
People with functional seizures should learn to recognize warning signs and develop strategies to prevent injury during and after episodes. It is important to be aware that relapses and flare-ups can occur despite treatment.
Recent Advances in Functional Neurologic Disorder Research
The National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health (NIH), is a leading supporter of FND research. NIH-funded scientists are working to advance our understanding of the neurobiology and pathophysiology of FND. Researchers are utilizing MRI and other neuroimaging techniques to identify biomarkers—biological indicators of disease—that can be used for diagnosis, risk assessment, and monitoring disease progression. These efforts aim to develop improved diagnostic tests and treatments for FND.
Learn About Clinical Trials
Clinical trials are research studies that help us learn more about diseases and improve care. They offer patients access to new and emerging treatment options.
How to Improve Care for People with Functional Neurologic Disorder
Consider participating in clinical research to help clinicians and scientists better understand FND and related disorders. Clinical research relies on the participation of individuals, both healthy and those with illnesses, from diverse backgrounds and demographics. This ensures that study results are applicable to a broad population and that treatments are 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 recruiting people with FND at Clinicaltrials.gov.
Resources for More Information about Functional Neurologic Disorder
- FND Hope International
- Functional Neurological Disorders Society (For physicians and researchers)
