What are the symptoms and management of Functional Neurological Disorder (FND)?

Symptoms of Functional Neurological Disorder (FND)

FND presents with genuine neurological symptoms that are internally inconsistent, disproportionate to examination findings, and demonstrate variability with attention—these positive clinical features establish the diagnosis rather than exclusion of other diseases. 1

Motor Symptoms

• Functional limb weakness manifests as weakness that improves during distraction, shows inconsistent patterns during examination, and demonstrates give-way weakness that differs from neurological patterns 1, 2
• Movement disorders including tremor that varies in amplitude with distraction, dystonia with abnormal postures that worsen with attention, and jerky movements that are distractible 1, 3
• Gait abnormalities characterized by excessive effort, struggle behaviors, and patterns inconsistent with recognized neurological disorders 1, 4
• Parkinson's-like symptoms with motor features that show distractibility and variability during functional activities 5

Dissociative Seizures (Non-Epileptic Seizures)

• Seizure-like episodes that differ from epileptic seizures, with patients often retaining some awareness or memory of events despite appearing unresponsive 2, 3
• Episodes typically last longer than epileptic seizures, have gradual onset, and show side-to-side head movements rather than rhythmic jerking 2
• Patients may hear and understand during episodes even when unable to respond 2

Communication and Swallowing Symptoms

• Functional dysphonia presenting as total or partial voice loss despite normal vocal fold structure and function on laryngoscopy 1
• Speech disorders including articulation problems, dysfluency, and functional foreign accent syndrome where symptoms resolve or reduce during spontaneous conversation or when attention is diverted 1
• Dysphagia (swallowing difficulties) and globus sensation (feeling of something stuck in throat) that are disproportionate to any structural findings 1
• Symptoms show internal inconsistency—severity fluctuates during small talk versus formal assessment, and improves with distraction 1

Sensory Symptoms

• Functional visual impairment experienced as persistent absence of vision, intermittent loss, or reduced visual acuity without corresponding ophthalmological findings 1
• Sensory disturbances including altered sensation, numbness, or hypersensitivity that don't follow anatomical nerve distributions 3, 6

Cognitive Symptoms

• Subjective cognitive difficulties affecting word finding, memory, concentration, reading, and writing that show significant internal inconsistency compared to lesion-based patterns 1, 3
• Performance during formal testing is disproportionately impaired compared to day-to-day functioning 1
• These symptoms often reflect inefficient allocation of attentional resources rather than true cognitive deficits 1

Associated Symptoms

• Chronic fatigue is commonly experienced as part of the disorder and can perpetuate other symptoms 3, 6
• Persistent pain frequently co-occurs with motor and sensory symptoms 3, 6
• Anxiety is common (though not universal) and can act as both precipitating and perpetuating factor 1, 3

Key Diagnostic Features Across All Symptom Types

• Internal inconsistency: Symptoms vary in ways that don't follow recognized neurological patterns—for example, weakness that improves when attention is diverted or symptoms that resolve during automatic movements 1
• Disproportionate severity: Symptom severity exceeds what would be expected from examination findings, imaging, or the nature of any precipitating injury 1
• Suggestibility: Symptoms become more prominent when discussed or examined, and may improve with distraction techniques 1
• Inefficient movement patterns: When weakness is the complaint, movements show excessive effort, struggle behaviors (overmouthing, eye blinking, facial contortions), and muscle hyperfunction rather than true weakness 1

Perpetuating Factors That Maintain Symptoms

• Hypervigilance and self-monitoring: Excessive attention to bodily sensations and symptom monitoring 1, 3
• Fear-avoidance behaviors: Belief that movement or function is dangerous, leading to activity avoidance 1
• Physiological arousal: Heightened anxiety and stress responses that exacerbate symptoms 1, 3
• Illness beliefs: Conviction that symptoms indicate structural damage or disease despite reassurance 1, 5
• Secondary factors: Poor sleep, pain, fatigue, and medication side effects that compete for cognitive resources 1, 3