Gender disparity and abuse in functional movement disorders: a multi-center case-control study

Functional Neurologic Disorder, La Lésion Dynamique: 2024 Wartenberg Lecture

Functional neurologic disorder is common and a significant cause of disability and stress in neurologic patients. The nature of this disorder has been unclear. Originally called hysteria, the disorder interested Charcot who postulated that a functional lesion, la lésion dynamique, was responsible. Recent studies of functional neurologic disorders now allow us to understand what la lésion dynamique is and identifies these disorders without ambiguity as arising from the brain. Functional neurologic disorders are best understood as a multifactorial process with a biopsychosocial model. There can be a genetic predisposition. Commonly there is early life trauma that leads to a developmental abnormality of the amygdala, including loss of inhibition. This abnormality can be considered a predisposing factor. When stressed, the amygdala becomes hyperactive, driving the limbic system to cause widespread network dysfunction in the brain. This dysfunction can improve, correlating with clinical improvement. Network dysfunction is becoming recognized as an important pathologic process in neurology and psychiatry, as real as any other pathology. We should be able to make progress in helping patients with functional neurologic disorders with this understanding of la lésion dynamique.

Functional neurological disorder in pregnancy, labour and the postpartum period: systematic review

AIMS AND METHOD

Functional neurological disorder (FND) most often presents in women of childbearing age, but little is known about its course and outcomes during pregnancy, labour and postpartum (the perinatal period). We searched MEDLINE, PsycInfo and Embase combining search terms for FND and the perinatal period. We extracted data on patient demographics, subtype of FND, timing of symptom onset, comorbidities, medications, type of delivery, investigations, treatment, pregnancy outcomes and FND symptoms at follow-up.

RESULTS

We included 36 studies (34 case reports and 2 case series) describing 43 patients. Six subtypes of FND were identified: functional (dissociative) seizures, motor weakness, movement disorder, dissociative amnesia, speech disorders and visual symptoms. New onset of perinatal FND was more common in the third trimester and onwards. Some women with functional seizures were exposed to unnecessary anti-seizure prescriptions and intensive care admissions.

CLINICAL IMPLICATIONS

Prospective studies are urgently needed to explore how FND interacts with women's health in the perinatal period.

Moving Beyond Movement: Diagnosing Functional Movement Disorder

Functional movement disorder (FMD) is a complex neuropsychiatric syndrome, encompassing abnormal movements and weakness, and is a common cause of potentially disabling neurological symptoms. It is vital to recognize that FMD is a syndrome, with nonmotor manifestations negatively affecting a patient's quality of life. This review highlights a diagnostic algorithm, where a history suggestive of FMD is combined with the presence of positive signs on examination and appropriate investigations to make the diagnosis. Positive signs indicate internal inconsistency such as variability and distractibility, and clinical findings that are incongruent with other known neurological disease. Importantly, the clinical assessment acts as the first opportunity to allow patients to understand FMD as the cause for their symptoms. Accurate and early diagnosis of FMD is necessary given that it is a treatable and potentially reversible cause of disability, with significant risk of iatrogenic harm associated with misdiagnosis.

Functional neurological disorder: new subtypes and shared mechanisms

Functional neurological disorder is common in neurological practice. A new approach to the positive diagnosis of this disorder focuses on recognisable patterns of genuinely experienced symptoms and signs that show variability within the same task and between different tasks over time. Psychological stressors are common risk factors for functional neurological disorder, but are often absent. Four entities-functional seizures, functional movement disorders, persistent perceptual postural dizziness, and functional cognitive disorder-show similarities in aetiology and pathophysiology and are variants of a disorder at the interface between neurology and psychiatry. All four entities have distinctive features and can be diagnosed with the support of clinical neurophysiological studies and other biomarkers. The pathophysiology of functional neurological disorder includes overactivity of the limbic system, the development of an internal symptom model as part of a predictive coding framework, and dysfunction of brain networks that gives movement the sense of voluntariness. Evidence supports tailored multidisciplinary treatment that can involve physical and psychological therapy approaches.