What is Functional Neurological Disorder?

 

Functional Neurological Disorder (FND) is a condition in which the nerves in the brain and the rest of the body do not communicate correctly, even when no structural damage is present. 

 

This miscommunication in the nervous system leads to neurological symptoms including functional seizures, tremors, dystonia, weakness, gait disorders, sensory symptoms, speech symptoms, visual symptoms, and cognitive symptoms. Some if these disorders are usually episodic while others are more persistent. 

 

The symptoms of this disorder are not intentionally produced. They involve involuntary brain/behavioral processes, which nevertheless can be influenced by attention, expectation, learning, arousal, suggestion, and social context.

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Cause

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Some people with FND have no identifiable trigger. However, symptoms may develop or worsen following periods of physical or psychological stress. 

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Diagnostics

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Brain imaging and Video EEG - These tests help rule out other neurological conditions

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Clinical assessment- Diagnosis is supported by positive clinical findings showing patterns that are inconsistent with recognized structural neurological disease and demonstrate that normal neurological function remains possible under certain circumstances.

 

Functional seizures: forceful and prolonged eye closure, side to side head movements, lack of post-ictal/seizure confusion, variable and asynchronous movements, prolonged episodes, preserved perception, lack of lateral tongue biting. 

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Functional weakness: Hoover test – When a patient is asked to voluntarily extend the affected hip, little downward pressure may be produced. However, when the patient is asked to flex the opposite hip against resistance, normal involuntary extension pressure may return in the affected leg. This inconsistency demonstrates that the motor pathways and muscles are capable of producing strength even though the patient experiences weakness during voluntary movement.

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Management

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1. Education on the Diagnosis 

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Patients have better outcomes when they understand their diagnosis. Before diagnosis, patients may interpret their condition as "something catastrophic is happening to my brain." That can produce fear, hypervigilance, autonomic arousal, and increased attention to bodily sensations, which may exacerbate or reinforce their condition. With a clear diagnosis, patients may also be more willing to learn techniques to identify triggers and learn management techniques. 

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2. FND-Specific Physical Therapy, Occupational Therapy, Psychological Therapy, and Speech-Language Therapy

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These FND-specific therapies use techniques that manipulate attention, movement patterns, expectations, and learned responses to help restore more automatic and normal neurological functioning. Treatment often involves reducing excessive attention to the affected movement or symptom, redirecting attention toward the task or environment, and retraining normal movement through automatic or less consciously controlled activities. Physical therapy may use distraction, rhythmic or automatic movements, altered movement strategies, and gradual retraining of normal movement. Occupational therapy can help patients apply these strategies to everyday activities. Psychological therapy can help identify and modify factors such as symptom-focused attention, fear, avoidance, stress, and learned behavioral responses that may perpetuate symptoms. Speech-language therapy can use similar principles to retrain functional speech, voice, swallowing, or communication symptoms.

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                                                       References & Guidelines

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• American Academy of Neurology (AAN). Practice Guideline on Management of Functional Seizures.

• Espay AJ, et al. Current Concepts in Diagnosis and Treatment of Functional Neurological Disorders. JAMA Neurology.

• Nielsen G, et al. Physiotherapy for Functional Motor Disorders: A Consensus Recommendation. Journal of Neurology, Neurosurgery & Psychiatry.

• Nicholson C, et al. Occupational Therapy Consensus Recommendations for Functional Neurological Disorder. Journal of Neurology, Neurosurgery & Psychiatry.

• International League Against Epilepsy (ILAE). Clinical guidance regarding psychogenic nonepileptic/functional seizures.