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Functional Neurological Disorder

Functional neurological disorder (FND) is a condition that includes motor, cognitive, and/or sensory symptoms that are genuinely experienced and related to neurological functioning rather than differences in underlying structure[1]

 

FND has previously been called conversion disorder, psychogenic disorder, and hysteria[1]

 

Statistics[1]

  • Incidence (new cases) is 12/100,000 per year

  • Affects women more than men (3 women: 1 man)

  • Can occur across ages (although rare under age 10)

  • Misdiagnosis (diagnosing FND when a different cause is the reason for the symptoms) is very low

Dissociative/Functional Seizures

 

Dissociative or functional seizures are sudden events that resemble epileptic seizures or fainting.  Dissociative seizures often have[1]

  • A longer duration (>90 seconds),

  • A fluctuating course,

  • Side-to-side head or body movement,

  • Closed eyes, & 

  • Memory of the event

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Frequent events where one suddenly falls down and lays still with their eyes closed for more than a minute is a strong indicator of FND

 

In contrast, epileptic seizures have post seizure confusion and laboured breathing

 

Recent studies have shown that dissociative/functional seizures share many characteristics of panic attacks - often a brief escalation of symptoms, with autonomic arousal.

  • Seizure activity has been viewed as an involuntary, learned, brain ‘reflex’ to manage unwanted sensations (almost like clearing the cache of the brain)

Functional Cognitive Symptoms

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Many people with FND experience memory and concentration challenges[1]

  • Included are attentional differences, such as 

    • Losing concentration when taking, 

    • Walking into rooms and forgetting what you went there for, 

    • Difficulty recalling overlearned information (PIN numbers and passwords), and 

    • Mild word-finding difficulties

 

Cognitive testing for challenges in FND is often not helpful as patients with FND may excel on tests despite their symptoms

Other Functional Symptoms​

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Women with FND have a high prevalence of 

  • Other FND symptoms (e.g., irritable bowel syndrome and fibromyalgia/widespread chronic pain or chronic fatigue syndrome) and 

  • Higher than expected use of opiates due to chronic pain.  

  • Women may also experience possible chronic intermittent urinary retention[1,4]

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Paruresis (shy bladder), may affect up to 7% of the male population, and occurs when a person is unable to urinate when others are present, such as in a public toilet. 

 

The social, work, and romantic lives of those with FND can be significantly affected[1]

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Other symptoms include[1]

  • Speech problems (such as dysarthria, mutism or foreign accent syndrome); 

  • Sensory symptoms (including numbness, visual loss; hearing loss or sensitivity; globus (feeling like there is a lump in your throat when there isn’t), and persistent postural perceptual dizziness 

 

Note: FND does not include pain or fatigue; although those symptoms are very common in combination with FND and almost certainly have shared mechanisms in the nervous system

Biopsychosocial Framework​​

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In the past, primary risk factors for FND were co-occurring psychiatric disorders, a history of childhood abuse, and being female[2]​

 

More recently, environmental factors, including neglect[2], physical and sexual trauma[3] have been identified to play a role 

  • Chronic pain, fatigue, somatization (body symptoms), and unemployment are commonly reported in FND patients[2]

 

Studies have shown that patients with Functional Seizure symptomology have higher rates of anxiety and increased prevalence of childhood physical or sexual abuse, and neglect compared to those with Functional Movement symptomology[2]

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Prevalence of mood disorders, gender breakdown, educational level, and employment status were not significantly different between patients  who experience Functional Seizure and Functional Motor symptomologies​

 

Case reports have suggested that FND may be linked to unique stressors observed in sexual minority communities (for example, hiding one’s sexual orientation, the coming out process, and real/perceived societal rejection)[3]

 

Two studies suggest FNDs are higher among the those in the gender minority community compared with cisgender populations[3]

Treatment Approaches â€‹

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Many people with FND have negative experiences with healthcare, due to a combination of doctor’s lack of knowledge about FND and the tendency for healthcare professionals to disbelieve patients with FND[1]

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Addressing the social conditions that may contribute to or cause FND is helpful (i.e., the social determinants of health)[3] and include 

  • Treating depression and anxiety[1]

  • Trauma therapy for abuse and neglect (e.g., EMDR)[3]

 

Clinical behavioural approach may help patients with functional cognitive disorders[1]:

  • Contextualize memory lapses, 

  • Practice grounding strategies

  •  

Clinical behavioural approach may help patients with functional seizures[1,2]:

  • Tackle unhelpful avoidance due to fear of seizures, and 

  • Tackle excessive and counterproductive use of cognitive safety strategies

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Clinical behavioural approach may help patients with functional movement disorders[1]

  • Movements may be worse when attention is paid to them

  • Physiotherapy techniques that take attention away from the movement are helpful to relearn movement patterns:

  • Approaches that may seem paradoxical (example, better at walking or running on a treadmill than walking normally)

  •  Music or using other ‘automatic’ learnt movements from dancing can help access better movement. 

  • These approaches are consensus recommendations

References​

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  1. Bennett, K., Diamond, C., Hoeritzauer, I., Gardiner, P., McWhirter, L., Carson, A., & Stone, J. (2021).  A practical review of functional neurological disorder (FND) for the general physician. Clinical Medicine, 21, 28–36.
     

  2. Kola, S., & LaFaver, K. (2022). Functional movement disorder and functional seizures: What have we learned from different subtypes of functional neurological disorders? Epilepsy and Behavior Reports, 18, 100510
     

  3. Lerario, M. P., Rosendale, N., Waugh, J. L., Turban, J., & Maschi, T. (2023). Functional Neurological Disorder among sexual and gender minority people. Neurologic The Clinica, 41, 759-781 https://doi.org/10.1016/j.ncl.2023.02.010
     

  4. Gonzalez-Herrero, B., Morgante, F., Pagonabarraga, J., Stanton, B., & Edwards, M. J. (2023). Autism Spectrum Disorder may be highly prevalent in people with functional neurological disorders. Journal of Clinical Medicine, 12, 299.https://doi.org/10.3390/jcm12010299

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