Diagnosis and treatment of functional myoclonus

Clinical neurophysiological evaluation for simple motor tics

BACKGROUND: An increase in functional movement disorders (FMDs) was perceived during the pandemic and an objective assessment of the same was performed. OBJECTIVE: To assess the frequency of FMDs during the coronavirus disease 2019 (COVID-19) pandemic compared to the pre-pandemic period and to identify the factors causing its increased incidence. METHODS: This cross-sectional comparison study conducted during the COVID-19 pandemic included patients attending the neurology outpatient department at a tertiary care center over a 6-month period. Those with FMDs documented by video evidence were compared against a baseline in the pre-pandemic period. Demographics, clinical features, duration of FMDs, presence of psychiatric comorbidity, as well as anxiety [by the Hospital Anxiety and Depression Scale (HADS-A)], depressive symptoms (HADS-D), and sleep quality by the Pittsburgh sleep quality index (PSQI) were recorded. RESULTS: Twenty-two out of 382 patients [64% women; age, 24.7 years (4–68)] examined during the pandemic (6 months) had FMDs compared to 31/1462 [67% women; age, 26.9 years (5–63)] examined in the pre-pandemic period, showing a 2.71-time increase. Among FMDs, functional myoclonus was the most common (36.4%), followed by functional gait disorder (27.2%), functional tremor (18.2%), functional dystonia (9.1%), and mixed phenotype (9.1%). Furthermore, 90.9% had an abnormal score (>11) on HADS-A or HADS-D and 86.3% had a score of >5 on PSQI, indicating poor sleep quality. There was a strong correlation between higher anxiety scores (P < 0.001) and poor sleep quality (P < 0.005) with an increase in frequency of FMD during the pandemic. CONCLUSION: The frequency of FMDs was 2.71 times higher during the pandemic, suggesting the vulnerability of predisposed patients (as evidenced by their elevated HADS scores) during stressors. Coexistent anxiety and depression increase the risk of FMDs, of which functional myoclonus was the most common phenotype, followed by gait disorders and functional tremor. Recognizing this entity will help avoid unnecessary work-up, which can be economically draining in such trying times.

BACKGROUND: Myoclonus is a rapid, brief, involuntary jerking of a muscle or group of muscles. It can arise from various etiologies, and it may be a predominant feature in several movement disorders. Understanding the diverse causes of myoclonus is essential for managing it effectively. OBJECTIVES: Studies reporting the clinical and etiological profiles of myoclonus are sparse. We aimed to describe the clinical and etiological profiles of patients visiting our movement disorders clinic, with myoclonus as the predominant manifestation. METHODS: Demographic data (age of onset and presentation, gender), disease-related data (disease duration, myoclonus characteristics, associated neurological features and comorbidities), and results of relevant laboratory investigations, along with brain magnetic resonance imaging and electroencephalogram, were collected. RESULTS: A total of 73 (6.4%) of 1140 movement disorder patients had predominant myoclonus. The median (IQR) age of onset, age at presentation, and disease duration were 43 (30–51.5) years, 46 (37–57.5) years, and 36 (12–84) months, respectively. Thirty-nine (53.4%) patients were male. Of the 73 cases, 52 (71.2%) patients had peripheral myoclonus, all having hemifacial spasm (HFS). The remainder had central myoclonus, with subacute sclerosing panencephalitis (SSPE) and functional myoclonus being common, followed by drug-induced and sporadic Creutzfeldt–Jakob disease. CONCLUSION: Nearly 7% of the patients visiting our movement disorders clinic had myoclonus as the predominant phenomenology. Peripheral myoclonus was diagnosed in more than two-thirds of these patients, with HFS being the sole disorder in this group. SSPE and functional myoclonus were the common central myoclonic disorders.

ObjectiveOur goal was to investigate the occurrence of functional movement disorders (FMDs) in Huntington disease gene expansion carriers (HDGECs) and individuals at risk of harboring a pathological CAG expansion in...

Functional movement disorders (FMDs) are a complex medical problem requiring a set of different diagnostic and treatment approaches: neurological, psychiatric, psychotherapeutic, and neurophysiological. With the advent of positive criteria for the diagnosis of FMDs, the latter are no longer just a diagnosis of exclusion, which is difficult for clinical interpretation. The review considers positive clinical and instrumental diagnostic criteria and presents the neurophysiological characteristics of functional tremor and functional myoclonus, which allow one to suspect this diagnosis. Their timely recognition is extremely important, as this permits patients to reduce the cost of unnecessary examinations and ineffective drugs and increases the chances for successful treatment, since the best prognosis is noted with the shortest duration of the disease.

There are several types of myoclonus, with a variety of classification schemes, and the clinician must determine what type of myoclonus a patient has and what type of neurophysiological assessment can facilitate diagnosis. The electromyographic (EMG) correlate of the myoclonus should be examined, including the response to sensory stimuli (C-reflex). The electroencephalographic (EEG) correlate of the myoclonus should then be examined, possibly including back-averaging from the myoclonus or looking at corticomuscular (EEG–EMG) coherence. The somatosensory evoked response (SEP) should be obtained. Such studies will help determine the myoclonus origin, most commonly cortical or brainstem. One form of cortical myoclonus has the clinical appearance of a tremor (cortical tremor). Brainstem myoclonus includes exaggerated startle (hyperekplexia). Other forms of myoclonus include spinal myoclonus and functional myoclonus, which have their own distinct physiological signature. Several causes of myoclonus are reviewed, including rare types such as Creutzfeldt-Jakob disease and subacute sclerosing panencephalitis.

In recent years, the term "functional" is starting to replace "psychogenic" when referring to a specific group of movement disorders, with an increasing emphasis being placed on the role of neurologists in the management of these disorders. These conditions are common and disabling, and sometimes difficult to diagnose. History taking and physical examination may highlight positive signs suggestive of diagnosis, which should not be based on exclusion. During examination, the distraction sign may be observed. When functional myoclonus is present, the patient's movements may vary over time. The role of a neurologist is not only to diagnose functional movement disorders, but also explain to the patient that the patient has a distinct neurological disorder and provide clinical evidence that supports the diagnosis. It is useful to share the positive signs with patients when explaining the diagnosis. In this article, I describe a patient with functional abdominal jerks to demonstrate how a diagnosis is made and how one can explain the diagnosis to the patient. Once a patient accepts and understands the diagnosis, treatment can be initiated. Collaboration with psychiatrists and physiotherapists is essential. It has been shown that cognitive behavioral therapy and physiotherapy are beneficial in ameliorating functional movements.

BackgroundPsychogenic Non-Epileptic Seizures (PNES) and Functional Motor Disorders (FMDs) commonly represent the main clinical manifestations of Functional Neurological Disorders (FNDs). Despite their high prevalence in pediatric neurological services, literature on this topic is still spare for this population.The present study aimed to deepen the clinical knowledge of a pediatric FNDs sample through a demographic and clinical characterization of the most recurrent clinical patterns during the pediatric age. Moreover, a comparison of neuropsychological and psychopathological profiles of PNES and FMD patients was carried out to identify specific vulnerabilities and therapeutic targets linked with these different clinical manifestations. Materials and methodsA total of 43 FNDs patients (age range 7–17 years old) were retrospectively included in our study, enrolled in two subgroups: 20 with FMDs and 23 with PNES diagnosis. They were inpatients and outpatients referred over a period of 5 years and a standardized neurological, neuropsychological (WISC-IV/WAIS-IV), and psychiatric (CDI-2, MASC-2, ADES, DIS-Q, PID-5) evaluation was assessed. ResultsIn PNES patients the most common clinical phenotypes were functional tonic-clonic (52%) and atonic (32%) manifestations while in the FMDs group were gait alterations (60%), functional myoclonus (35%), and tremor (35%). A higher frequency of cognitive impairment was reported in PNES patients with higher anxiety-depressive symptom rates than FMDs patients. ConclusionsNotably, specific neurocognitive and psychopathological profiles were described in PNES and FMDs, highlighting higher cognitive and psychiatric vulnerabilities in PNES, suggesting as well different strategy for therapeutic approaches.

Event related desynchronisation predicts functional propriospinal myoclonus

Psychogenic movement disorders are a heterogeneous group of conditions characterised by functional motor symptoms that cannot be attributed to any known neurological pathologies. Different mechanisms are still applied to the explanation of these conditions, including exaggeration of normal physiological responses, over- and under-focus on symptoms, symbolic response to psychological trauma, and cultural ideas about the concept of illness. Cases of functional tremor and functional dystonia together account for around 70% of psychogenic movement disorders. Functional myoclonus and functional gait disturbances have also been traditionally included in the psychogenic movement disorder group. Recent research has highlighted the need for clinical diagnostic tests based on positive signs, rather than diagnoses of exclusion of organic pathology in patients with psychiatric conditions. Treatment approaches to psychogenic movement disorders show wide variability and are often empirical. The diagnostic consultation itself could be a key part of the treatment intervention, especially if the clinician adopts non-judgmental approaches and highlights the reversible nature of the functional symptoms as part of psychoeducation.

Functional jerky movements (or functional myoclonus) are commonly seen in patients with functional movement disorder. Positive features both from history and clinical examination are important for the diagnosis. However, due to their heterogeneous and paroxysmal nature a home-made video-recording of the jerky movements can be essential to make the diagnose by a movement disorder specialist. Supportive clinical clues include abrupt symptom onset often triggered by a physical event, whereas entrainment and distractibility are supportive signs during physical examination. Localization of the jerky movements, especially proximal localization, is supportive, and can also be helpful in distinguishing functional jerks from tics and myoclonus, which are the most important differential diagnostic considerations. Additional neurophysiological tests include polymyography and electroencephalography-electromyography (EEG-EMG) co-registration in order to demonstrate a readiness potential (RP). Management includes disease education and specialized physical therapy.KeywordsFunctional movement disorderJerksMyoclonusTicsClinical neurophysiology

Functional myoclonus: Time to stop jerking around with negative diagnosis

Functional movement disorders (FMD) are defined by diverse phenotypes of altered movements that lack corresponding pathology in an anatomical region, and are typically characterized by inconsistent findings on neurological examination. While there are several suggestive clinical features indicating FMD, objective biomarkers are still lacking. We conducted a systematic review of the literature with an emphasis on literature published after February 2019 aiming to summarise current knowledge on biomarkers of FMD. We divided our findings into four main categories: genetic, biofluid, neuroimaging, and electrophysiological biomarkers. For the differential diagnosis of functional tremor, functional tic-like behaviours (FTLB), and functional myoclonus, previous studies support the use of electrophysiological biomarkers. Evidence from neuroimaging research supports the multi-network model of FMD as a condition affecting the attentional, sensorimotor, self-agency/multimodal integration, and limbic/salience circuits. Biomarkers such as neurofilament light chain, inflammatory, and autoimmune factors should still be considered experimental, since results are based on small sample sizes. There is preliminary evidence from a genetic study that in FMD there is a complex interaction between individual predisposing risk genes involved in the serotonergic pathway. Although the diagnosis of FMD remains challenging, and depends mainly on clinical judgement, research is underway to identify potential biomarkers to improve diagnostic confidence. Previous studies indicate that, in addition to psychological symptoms, biological changes can be detected in patients with FMD. This is evidenced by different patterns of neurotransmission related to stress responses and emotional regulation. We believe it is vital to conduct larger trials in diverse populations from different regions of the world in order to find more reliable biomarkers of FMD.

PL3. Clinical neurophysiology of movement disorders – Example of functional movement disorders

Functional movement disorders (FMD) are proposed to reflect a specific problem with voluntary control of movement, despite normal intent to move and an intact neural capacity for movement. In many...