Recognising and explaining functional neurological disorder

Stone, Jon; Burton, Christopher; Carson, Alan

doi:10.1136/bmj.m3745

Cited by 47 publications

(60 citation statements)

References 34 publications

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“…Traditionally, the absence of an explanatory organic impairment is part of the diagnostic criteria of functional disorders (e.g., in the current European diagnostic system ICD-10, World Health Organization, 2004 ). Today, we experience a major paradigm shift in clinical medicine, with positive signs becoming more and more important in the diagnosis of functional disorders ( American Psychological Association, 2013 ; Stone, 2016 ; Stone et al, 2020 ). Within this paradigm shift, identifying a—potentially unifying—pathophysiological mechanism is of high clinical relevance, as it would help to improve the positive definition, swift diagnosis, and treatment of functional disorders.…”

Section: Introductionmentioning

confidence: 99%

Unstable Gaze in Functional Dizziness: A Contribution to Understanding the Pathophysiology of Functional Disorders

et al. 2021

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Objective: We are still lacking a pathophysiological mechanism for functional disorders explaining the emergence and manifestation of characteristic, severely impairing bodily symptoms like chest pain or dizziness. A recent hypothesis based on the predictive coding theory of brain function suggests that in functional disorders, internal expectations do not match the actual sensory body states, leading to perceptual dysregulation and symptom perception. To test this hypothesis, we investigated the account of internal expectations and sensory input on gaze stabilization, a physiologically relevant parameter of gaze shifts, in functional dizziness.Methods: We assessed gaze stabilization in eight functional dizziness patients and 11 healthy controls during two distinct epochs of large gaze shifts: during a counter-rotation epoch (CR epoch), where the brain can use internal models, motor planning, and resulting internal expectations to achieve internally driven gaze stabilization; and during an oscillation epoch (OSC epoch), where, due to terminated motor planning, no movement expectations are present, and gaze is stabilized by sensory input alone.Results: Gaze stabilization differed between functional patients and healthy controls only when internal movement expectations were involved [F(1,17) = 14.63, p = 0.001, and partial η2 = 0.463]: functional dizziness patients showed reduced gaze stabilization during the CR (p = 0.036) but not OSC epoch (p = 0.26).Conclusion: While sensory-driven gaze stabilization is intact, there are marked, well-measurable deficits in internally-driven gaze stabilization in functional dizziness pointing at internal expectations that do not match actual body states. This experimental evidence supports the perceptual dysregulation hypothesis of functional disorders and is an important step toward understanding the underlying pathophysiology.

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Section: Introductionmentioning

confidence: 99%

Unstable Gaze in Functional Dizziness: A Contribution to Understanding the Pathophysiology of Functional Disorders

et al. 2021

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“…More recently, the focus has shifted on altered agency [15,33,34], which was considered the expression of disordered perceptions and altered by insufficient suppression of priors recruited by top-down perception processing [33][34][35].…”

Section: Other Potential Mechanismsmentioning

confidence: 99%

“…The recent neurologic literature has proposed a clear-cut separation of conversion/functional neurologic disorders (FND) from factitious disorders [14,15]. However, as mentioned above, the DSM classification system underlines the frequent overlap between different forms of somatic symptom disorders, once termed hysteria and, therefore, a hystero-malingering continuum has been suggested [12,16].…”

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confidence: 99%

The factitious/malingering continuum and its burden on public health costs: a review and experience in an Italian neurology setting

et al. 2021

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Factitious disorder is classified as one of the five aspects of somatic symptom disorders. The fundamental element of factitious disorder is deception, i.e., pretending to have a medical or psychiatric disorder, but the enactment of deception is considered unconscious. Indeed, volition, i.e., the perception of deliberate deception, is blurred in patients presenting with factitious disorder. In the USA and the UK, factitious disorder has received constant media attention because of its forensic implications and outrageous costs for the National Health Systems. Unfortunately, a comparable level of attention is not present in Italian National Health System or the Italian mass media. The review analyzes the classifications, disorder mechanisms, costs, and medico-legal implications in the hope of raising awareness on this disturbing issue. Moreover, the review depicts 13 exemplification cases, anonymized and fictionalized by expert writers. Finally, our paper also evaluates the National Health System’s expenditures for each patient, outlandish costs in the range between 50,000 and 1 million euros.

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“…Importantly, and as outlined in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, 1 these symptoms are not deliberately generated or feigned by the patient; and although FND has been traditionally viewed as an exclusion diagnosis, new models based on the most recent evidence have proposed a positive diagnosis based on specific neurological signs, such as Hoover’s sign. 2 , 3 …”

Section: Introductionmentioning

confidence: 99%

Improvement of functional neurological disorder after administration of esketamine nasal spray: a case report

Vendrell-Serres

Soto-Angona

Rodríguez‐Urrutia

et al. 2021

Therapeutic Advances in Psychopharmacology

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Functional neurological disorder (FND) is a complex neuropsychiatric condition characterized by the presence of neurological symptoms and signs (either motor or sensory) that cannot be explained by any known medical or mental disease. It is frequently presented with psychiatric comorbidities, such as major depression. Its prognosis is poor, with low improvement or recovery rates at 1 year after their onset, and no particular treatment has demonstrated significant efficacy in this regard. Here, we describe the management of a patient affected by treatment-resistant depression (TRD) and FND characterized by mixed paralysis (sensory and motor) in the left arm, and who was successfully treated with esketamine nasal spray, achieving remission in both disorders. The US Food and Drug Administration and the European Medicines Agency recently approved esketamine, the S-enantiomer of ketamine, for treatment of TRD. It is a fast-acting drug that provides a rapid-onset improvement of depressive symptoms. We have presented the first case, to our knowledge, of functional neurological symptoms being successfully treated with esketamine in a patient with comorbid TRD. While the novelty of this data implies a clear need for further research, it is suggested that esketamine might be a useful tool for the treatment of FND, acting through different theorized mechanisms that are in tune with recent advances in knowledge of the etiopathology of FND.

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Recognising and explaining functional neurological disorder

Cited by 47 publications

References 34 publications

Unstable Gaze in Functional Dizziness: A Contribution to Understanding the Pathophysiology of Functional Disorders

Unstable Gaze in Functional Dizziness: A Contribution to Understanding the Pathophysiology of Functional Disorders

The factitious/malingering continuum and its burden on public health costs: a review and experience in an Italian neurology setting

Improvement of functional neurological disorder after administration of esketamine nasal spray: a case report

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