What is Functional Neurological Disorder?

Functional Neurological Disorder (FND) is a complex condition that affects the functioning of the nervous system, resulting in symptoms that cannot be explained by a conventional neurological disease or structural abnormality in the brain. Unlike disorders such as multiple sclerosis or epilepsy, where clear physical changes in the brain or nerves are evident, FND arises from disruptions in how the brain and body communicate, impacting voluntary motor or sensory functions (National Institute of Neurological Disorders and Stroke [NINDS], n.d.).

FND manifests in a wide variety of symptoms that can closely resemble those of other neurological disorders. Common presentations include seizures (non-epileptic seizures), muscle weakness or paralysis, abnormal movements (such as tremors or spasms), speech difficulties, and sensory impairments (such as numbness or blindness). People with FND often experience a significant impact on their quality of life due to the unpredictable and disabling nature of the condition (Pick et al., 2021).

Epidemiological studies estimate that FND is relatively common, accounting for 6% to 16% of outpatient neurology clinic visits and 9% of emergency neurology presentations. It affects individuals of all ages and genders, though it appears to be more prevalent in women and typically develops in young to middle-aged adults (Espay et al., 2018). What Causes Functional Neurological Disorder?

The exact causes of FND remain elusive, but researchers believe that it arises from a combination of biological, psychological, and social factors. The condition is thought to involve changes in how the brain processes signals and controls motor or sensory functions rather than structural abnormalities or degeneration of the nervous system (Espay et al., 2018).

FND has been described as a condition wherein the normal pathways the brain uses to move, feel, speak, walk, or think, become disrupted, like a corrupted software application, such that different brain areas of the brain have difficulty communicating with one another.

Neurobiological Mechanisms Advances in neuroimaging have provided insights into the functional changes in the brain associated with FND. Studies suggest abnormal activity in regions responsible for attention, emotion, and motor control, such as the prefrontal cortex and limbic system. These findings highlight the brain's difficulty in appropriately interpreting and acting on internal and external signals, leading to the symptoms of FND (Pick et al., 2021).

Psychological and Social Factors Psychological stress, trauma, and adverse life events are frequently reported in individuals with FND. However, FND is not solely a psychological disorder; rather, it represents an interplay between the mind and body. Emotional distress and maladaptive coping mechanisms may influence brain function, exacerbating symptoms (Pick et al., 2021). Notably, not all individuals with FND have a history of psychological trauma, underscoring the condition’s multifactorial nature (Edwards et al., 2022).

What Are the Symptoms and Experiences of FND?

FND can present in diverse ways, mimicking symptoms of other neurological disorders. Key symptoms include:

• Motor Symptoms: Muscle weakness, paralysis, tremors, dystonia, or gait abnormalities.

• Seizures: Episodes resembling epileptic seizures but without abnormal electrical activity in the brain.

• Sensory Symptoms: Loss of sensation, tingling, or altered vision and hearing.

• Speech and Swallowing Difficulties: Slurred speech, aphonia (loss of voice), or difficulty swallowing (Espay et al., 2018).

The experience of FND varies widely among individuals. Some patients report acute onset of symptoms triggered by specific stressors, while others develop symptoms gradually. Living with FND often leads to frustration, stigma, and difficulty accessing appropriate care, as the condition is poorly understood by many healthcare providers and the general public (Pick et al., 2021).

How Is FND Diagnosed and Treated?

Diagnosis Diagnosing FND is challenging but increasingly guided by specific clinical criteria. Neurologists rely on positive signs from the physical exam, such as Hoover’s sign for functional limb weakness or inconsistencies in symptom presentation, rather than using FND as a diagnosis of exclusion. Advanced imaging and neurophysiological tests help rule out structural neurological diseases (Espay et al., 2018).

Treatment Approaches Treatment for FND is multimodal, focusing on improving function and quality of life rather than curing the condition. Current strategies include:

1. Education: Educating patients about FND’s mechanisms helps demystify the condition and reduce self-blame. Understanding that symptoms arise from brain dysfunction rather than imagined or malingering behavior can be empowering (Pick et al., 2021).

2. Physical and Occupational Therapy: Tailored rehabilitation programs aim to retrain motor and sensory functions, improving mobility and independence. Physiotherapists skilled in FND play a crucial role in guiding recovery (Edwards et al., 2022).

3. Psychological Therapy: Cognitive-behavioral therapy (CBT) and other psychotherapeutic approaches address stress, coping strategies, and any co-existing mental health issues such as anxiety or depression.

4. Medication: While there is no specific medication for FND, treatments may target associated symptoms, such as antidepressants for mood disorders or pain management strategies for chronic pain (Pick et al., 2021).

5. Neurorehabilitation: Multidisciplinary neurorehabilitation programs combine physical therapy, occupational therapy, and psychological support to improve neurological function and adaptability. This approach focuses on gradual functional improvement through repetitive training and retraining neural pathways.

6. Hypnotherapy: Emerging evidence suggests that hypnotherapy may benefit some individuals with FND by addressing subconscious processes that influence motor and sensory symptoms. Hypnotherapy is particularly effective for stress reduction and symptom management when combined with other therapeutic modalities (Pick et al., 2021).

7. Complementary and Alternative Medicine (CAM): Certain CAM therapies, such as mindfulness meditation, yoga, and acupuncture, have shown promise in alleviating FND symptoms by promoting relaxation and improving body awareness. While more research is needed to establish efficacy, these therapies can be a valuable adjunct to conventional treatments.

8. Neuromodulation Therapies: Techniques like transcranial magnetic stimulation (TMS) and biofeedback are being explored as innovative options for FND. These approaches aim to normalize brain activity patterns and enhance neural connectivity, potentially reducing symptoms and improving function.
   

Emerging research continues to highlight the importance of individualized and integrative treatment plans for FND. Collaboration among neurologists, psychologists, physiotherapists, and other specialists is essential to achieve the best outcomes for patients.

About the Author

Dr. David George is a leading expert in integrative psychiatry and neurological rehabilitation based in Scottsdale, AZ. With a focus on innovative and patient-centered care, Dr. George leads Neuregen, a multidisciplinary clinic offering cutting-edge treatments for a range of neurological conditions, including Functional Neurological Disorder (FND). His unique approach combines neuroscience, psychology, and personalized rehabilitation techniques to empower patients on their path to recovery.

References

Edwards, M. J., Stone, J., & Carson, A. (2022). Functional neurological disorder: New subtypes and shared mechanisms. BMJ, 376, o64. https://www.bmj.com/content/376/bmj.o64

Espay, A. J., Aybek, S., Carson, A., Edwards, M. J., Goldstein, L. H., Hallett, M., LaFaver, K., LaFrance, W. C., Lidstone, T., Nicholson, T., O’Neal, M., Perez, D. L., Stone, J., & Morgante, F. (2018). Current concepts in diagnosis and treatment of functional neurological disorders. JAMA Neurology, 75(9), 1132–1141. https://jamanetwork.com/journals/jamaneurology/article-abstract/2682656

National Institute of Neurological Disorders and Stroke (NINDS). (n.d.). Functional neurologic disorder. https://www.ninds.nih.gov/health-information/disorders/functional-neurologic-disorder

Pick, S., Goldstein, L. H., Perez, D. L., & Nicholson, T. R. (2021). Functional neurological disorder: An integrative model for clinical practice. Lancet Psychiatry, 8(3), 227–240. https://pmc.ncbi.nlm.nih.gov/articles/PMC7930164/

Stone, J., et al. (2023). Advances in understanding functional neurological disorder. NeuroImage: Clinical, 35, 103150. https://www.sciencedirect.com/science/article/abs/pii/S1357303923001500