A Critical Appraisal of the Whack-a-Mole and Swivel Chair Signs in the Diagnosis of Functional Movement Disorders.

BACKGROUND: The demonstration of positive signs during neurological examination is a cornerstone of the diagnosis of functional movement disorders, however, the available data supporting the diagnostic value of some of these signs is limited. OBJECTIVES: To determine the diagnostic value (sensitivity and specificity) of the "whack-a-mole" (WAM) and "swivel chair" (SC) tests in patients with functional movement disorders (FMD). METHODS: We enrolled patients with functional and organic movements in the WAM test if they exhibited tremor, dystonia, myoclonus, chorea, or tics. For the SC test, patients with a gait disorder as their primary impairment were recruited. Two blinded movement disorder specialists rated the presence of these signs in edited videos. RESULTS: Inclusion criteria were met by 42 patients with FMD and 65 patients with organic movement disorders. Both tests demonstrated high specificity (means, 78% and 96%), but their sensitivity was low (means, 52% and 37%). Interobserver agreement for the WAM sign was 0.77 in the FMD group, against 0.28 in patients with organic movement disorders, whereas Movement Disorders Clinical Practice for Review Only for the SC sign was 0.69 in both groups. CONCLUSIONS: The present study indicates that physicians must be cautious in the application and interpretation of these clinical signs in the diagnosis of functional movement disorders, and they should be carefully considered and used as necessary.

[Severe hypomagnesemia in a man with alcohol dependence: a forgotten electrolyte in a neglected population]. / Ernstig magnesiumtekort bij alcoholverslaving.

BACKGROUND: Symptoms of acute alcohol withdrawal like tremors, seizures and delirium are commonly treated with benzodiazepines and vitamins. When complaints are not reacting to this treatment, an alternative diagnosis must be considered. Although hypomagnesemia is present in at least 30 percent of the patients with alcohol dependence, it can provoke and maintain these complaints. CASE DESCRIPTION: We present a 43-year-old man with alcohol dependence, who shows neurological, muscular, and cardiac consequences of an undiagnosed hypomagnesemia. CONCLUSION: In daily clinical practice there is not enough attention for magnesium deficits, especially in patients with alcohol dependence. Serious complications can be prevented by recognizing and treating magnesium deficiency more adequately.

Health Care Utilization in Functional Neurologic Disorders: Impact of Explaining the Diagnosis of Functional Seizures on Health Care Costs.

Background and Objective: The objectives of this study were to investigate health care utilization costs of patients with video-electroencephalography (VEEG)-confirmed functional seizures (FS), determine whether patients who received a satisfactory functional neurologic disorder (FND) diagnosis explanation had reduced health care utilization compared with those with a poor explanation; and to quantify the overall health care costs 2 years prediagnosis and postdiagnosis for those receiving a different explanation. Methods: Patients with VEEG-confirmed pure FS (pFS) or mixed (functional seizure plus epileptic seizures) diagnosis between July 1, 2017, and July 1, 2019, were evaluated. Explanation of the diagnosis was determined "unsatisfactory" or "satisfactory" using self-developed criteria, and health care utilization data were collected using an itemized list. The subsequent costs 2 years post-FND diagnosis were compared with those 2 years before, and cost outcomes were compared between both groups. Results: In patients who received a satisfactory explanation (n = 18), total health care costs were reduced from $169,803 to $117,133 USD (-31%). An increase in costs was found ($73,430 to $186,553 USD = +154%) in patients with pPNES after an unsatisfactory explanation (n = 7). On an individual level, 78% with a satisfactory explanation saw a reduction in total health care costs per year (mean $5,111 USD to $1,728 USD), and in 57%, an unsatisfactory explanation led to an increase (mean $4,425 to $20,524 USD). A similar effect was seen from explanation on patients with a dual diagnosis. Discussion: The method of communicating an FND diagnosis has a significant impact on subsequent health care utilization. Those receiving satisfactory explanations demonstrated reduced health care utilization, whereas an unsatisfactory explanation resulted in additional expenses.

Hazard Perception Skill and Driver Behavior in Patients With Functional Neurologic Disorders.

BACKGROUND AND OBJECTIVES: Driving in patients with functional neurologic disorders (FND) is a major concern, but current guidelines (where they exist) are based on expert consensus only due to a lack of relevant empirical evidence. This study aimed to provide such evidence by comparing drivers with FND with healthy controls on aspects of driving performance and behavior important to crash risk, including hazard perception skill. METHODS: Participants completed validated self-report questionnaires of driving behaviors (assessing lapses, errors, violations, and attentional issues) and 2 computer-based measures of hazard perception skill (both known to be associated with crash risk). RESULTS: We compared 43 patients who experience dissociative attacks or functional motor symptoms and 43 healthy controls. Patients with FND self-reported significantly more driving lapses and driving errors compared with healthy controls. However, there were no significant between-group differences in self-reports of ordinary violations, aggressive violations, or attention-related errors. Participants in the FND group and healthy controls exhibited a similar performance on a response time hazard perception test (6.27 vs 5.51 seconds, p = 0.245). However, participants with FND remarkably outperformed the controls in the number of plausible predictions they made in a verbal response hazard prediction test (1.55 vs 1.18 predictions per clip, p = 0.006). DISCUSSION: Our findings suggest that the ability of drivers with FND to predict traffic hazards in between attacks or flares is not worse than that of healthy individuals, with the possibility that it might even be better under some circumstances. Further studies with various populations are needed to replicate our findings.

'Tricked' sensory trick: a geste antagoniste in functional dystonia.

A sensory trick, or geste antagoniste, is a manoeuvre used by patients with dystonia to ameliorate their dystonic movements or posturing. Typically, a sensory trick is a confirmatory clue indicating an organic nature of the dystonia. In this report, we present an extremely rare case of a sensory trick in a patient with functional dystonia.

A novel diagnostic approach for patients with adult-onset dystonia.

Adult-onset dystonia can be acquired, inherited or idiopathic. The dystonia is usually focal or segmental and for a limited number of cases causal treatment is available. In recent years, rapid developments in neuroimmunology have led to increased knowledge on autoantibody-related dystonias. At the same time, genetic diagnostics in sequencing technology have evolved and revealed several new genes associated with adult-onset dystonia. Furthermore, new phenotype-genotype correlations have been elucidated. Consequently, clinicians face the dilemma of which additional investigations should be performed and whether to perform genetic testing or not. To ensure early diagnosis and to prevent unnecessary investigations, integration of new diagnostic strategies is needed.We designed a new five-step diagnostic approach for adult-onset dystonia. The first four steps are based on a broad literature search and expert opinion, the fifth step, on when to perform genetic testing, is based on a detailed systematic literature review up to 1 December 2021.The basic principle of the algorithm is that genetic testing is unlikely to lead to changes in management in three groups: (1) patients with an acquired form of adult-onset dystonia; (2) patients with neurodegenerative disorders, presenting with a combined movement disorder including dystonic symptoms and (3) patients with adult-onset isolated focal or segmental dystonia. Throughout the approach, focus lies on early identification of treatable forms of dystonia, either acquired or genetic.This novel diagnostic approach for adult-onset dystonia can help clinicians to decide when to perform additional tests, including genetic testing and facilitates early aetiological diagnosis, to enable timely treatment.

Tremor Drugs in the Crosshairs.

Background: Alopecia areata is a rare but debilitating adverse effect of drugs used in the treatment of tremors. Recurrent hair loss after different types of tremor medications has never been described before. Case Report: We herein report the case of a 56-year-old tremor patient who we diagnosed with tremor-dominant Parkinson's disease. Unfortunately, she developed acute alopecia areata following the introduction of firstly levodopa/benserazide, secondly propranolol, and thirdly topiramate. Discussion: Our case report highlights alopecia areata as a possible side effect to a variety of drugs commonly used for tremor management. Fortunately, in most reported cases, as well as in our case, the hair loss is reversible.

Rare functional missense variants in CACNA1H: What can we learn from Writer's cramp?

Writer's cramp (WC) is a task-specific focal dystonia that occurs selectively in the hand and arm during writing. Previous studies have shown a role for genetics in the pathology of task-specific focal dystonia. However, to date, no causal gene has been reported for task-specific focal dystonia, including WC. In this study, we investigated the genetic background of a large Dutch family with autosomal dominant‒inherited WC that was negative for mutations in known dystonia genes. Whole exome sequencing identified 4 rare variants of unknown significance that segregated in the family. One candidate gene was selected for follow-up, Calcium Voltage-Gated Channel Subunit Alpha1 H, CACNA1H, due to its links with the known dystonia gene Potassium Channel Tetramerization Domain Containing 17, KCTD17, and with paroxysmal movement disorders. Targeted resequencing of CACNA1H in 82 WC cases identified another rare, putative damaging variant in a familial WC case that did not segregate. Using structural modelling and functional studies in vitro, we show that both the segregating p.Arg481Cys variant and the non-segregating p.Glu1881Lys variant very likely cause structural changes to the Cav3.2 protein and lead to similar gains of function, as seen in an accelerated recovery from inactivation. Both mutant channels are thus available for re-activation earlier, which may lead to an increase in intracellular calcium and increased neuronal excitability. Overall, we conclude that rare functional variants in CACNA1H need to be interpreted very carefully, and additional studies are needed to prove that the p.Arg481Cys variant is the cause of WC in the large Dutch family.

Locked-In Syndrome after Traumatic Basilar Artery Entrapment within a Clivus Fracture: A Case Report and Review of the Literature.

We report the case of a 58-year-old male with a rare vascular complication after traumatic head injury: entrapment of the basilar artery into a fracture of the clivus, ultimately leading to a locked-in syndrome due to brainstem infarction. Review of the literature revealed 19 earlier published cases of basilar artery entrapment within traumatic longitudinal clival fractures. In the majority of these patients there is an unfavorable neurological outcome.