Anna Sadnicka

Background: There is ongoing debate on the nature and the phenomenology of the golfers’ yips. Objectives: To clarify the phenomenology of the golfers’ yips, based on assessment of videos by expert neurologists. Methods: A panel of 13 movement disorder neurologists reviewed videos of 15 golfers (10 with and 5 without the yips). Videos showed wrist movements during putting, in three conditions: both hands, right and left hand only. The presence or absence of a movement disorder and its phenomenology was collected via a short questionnaire. Results: The video panel classified the yips as a movement disorder with high overall diagnostic accuracy (0.84[95% CI: 0.71–0.92, p < 0.001]) and significant inter‐rater reliability (Gwet‐AC1 = 0.56, 95% CI: 0.46–0.67, p < 0.001). The phenomenology was predominantly classified as dystonia with significant inter‐rater reliability (Gwet‐AC1 = 0.57, 95% CI: 0.44–0.69, p < 0.001). Conclusions: A panel of expert neurologists considered the golfers’ yips a neurological movement disorder, most consistent with dystonia.

Background: Reliable clinical phenotyping is crucial for diagnosis, treatment, and research in hyperkinetic movement disorders, yet its interrater reliability remains uncertain. Objectives: To quantify interrater agreement in clinical phenotyping of hyperkinetic movement disorders among experts in a large, phenotypically diverse cohort. Methods: Within the NEMO project, 161 patients with hyperkinetic movement disorders underwent standardized video assessments. Each patient was independently classified by three international movement disorders experts in a structured, stepwise procedure. Experts first assessed videos alone, then received clinical history and examination, and finally diagnostic test results. At each step, they assigned primary and secondary phenotypes and rated their diagnostic confidence. Interrater agreement was assessed using Fleiss’ and Cohen's kappa. Results: Across all phenotypes, interrater agreement on the primary phenotype increased with added information ( κ = 0.457 to κ = 0.607). Agreement with the NEMO reference classification similarly improved ( κ = 0.478 to κ = 0.656). Among patients with a single dominant phenotype, agreement reached κ = 0.78. In 93% of cases, at least two out of three experts reached consensus. Agreement was substantially lower in patients with mixed or complex presentations, such as myoclonus‐dystonia and functional movement disorders. Diagnostic certainty rose throughout, though secondary phenotype agreement remained poor. Experts rarely revised initial impressions, suggesting robust pattern recognition but also potential confirmation bias. Conclusions: Movement disorders specialists can reliably identify hyperkinetic phenotypes, even without in‐person assessment. While complex, mixed and functional presentations remain diagnostically challenging, our findings reinforce the value of expert phenotyping in clinical care, training, and research, and provide a benchmark for future studies and computational approaches.

Background: Cervical dystonia (CD) has a varied motor presentation, combining abnormal postures with complex involuntary head movements. Classification of these motor patterns remains imprecise, relying on descriptive terminology without robust definitions. Objectives: To provide a kinematically‐grounded description of the motor phenomenology of CD. Methods: Sixty‐two patients with CD and 32 age‐matched controls were recorded wearing inertial sensors. Voluntary movement was assessed during a head‐turning task, including velocity, range of motion, smoothness, and trajectory. Kinematic metrics were extracted from samples of involuntary movements and cluster analysis was applied to identify different patterns. These were then compared with clinical appraisal of movement phenotype. Exploratory factor analysis was conducted to investigate the relationship between motor characteristics. Results: Voluntary deficits included impaired velocity, range, smoothness, and symmetry, with no evidence of sequence effect. Three distinct clusters of involuntary head movement were identified: low‐frequency oscillations with a sawtooth waveform consisting of alternating fast and slow phases (Cluster 1); erratic mid‐frequency movements with constant changes in speed, waveform profile, and axis (Cluster 2); and high‐frequency sinusoidal movements (Cluster 3). Cluster 2 was specifically associated with a ‘jerky’ clinical phenotype, while Cluster 3 was associated with a ‘tremulous’ phenotype. Factor analysis identified distinct latent components driving variation in voluntary deficits and involuntary movement. Conclusions: CD is characterized by a heterogeneous combination of oscillatory movements and impairments in voluntary head control. Kinematic analysis has the potential to refine disease classification and support the development of objective instrumental outcome measures for clinical assessment and research. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

In functional neurological disorder (FND), there is a fundamental disconnect between an apparently intact nervous system and the individuals’ ability to consistently perform motor actions, perceive sensory signals and/or access effective cognition. Metacognition, the capacity to self-evaluate cognitive performance, appears highly relevant to FND pathophysiology. Poor metacognition is a potential mechanism via which abnormal models of self and the state of the world could arise and persist unchecked. There is therefore a justified enthusiasm that studies of metacognition may give substance to FND’s intangible nature. However, many assume an impairment in metacognition even though experimental studies are still in their infancy. This systematic review provides an analytical checkpoint of the evidence after the first five years of experimental work. We firstly summarize current methods for testing metacognition, prerequisite knowledge that allows readers to independently evaluate the evidence. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we then screened the 21 articles on this topic and review the experimental data of the eight studies that specifically tested metacognition in subjects with FND. Questionnaire metrics used to estimate global metacognition and general confidence in FND revealed a mixed picture of low or normal confidence. Of the five studies that used performance-controlled metrics, the gold-standard to estimate local metacognition in FND, four found metacognition to be equivalent to healthy controls and one paper supported impaired metacognition. We consequently try and broaden the debate and discuss alternative headline scenarios. We review how positive studies may offer insight and debate whether null studies could represent false negatives. However, since most studies find equivalent metacognition to controls, we also discuss whether metacognition could be intact and how this could inform mechanistic models of FND and have potential clinical utility. In summary, this review highlights signal of interest within the data, exposes current limitations and flags the many open questions.

Task-specific dystonia leads to loss of sensorimotor control for a particular motor skill. Although focal in nature, it is hugely disabling and can terminate professional careers in musicians. Biomarkers for underlying mechanism and severity are much needed. In this study, we designed a keyboard device that measured the forces generated at all fingertips during individual finger presses. By reliably quantifying overflow to other fingers in the instructed (enslaving) and contralateral hand (mirroring) we explored whether this task could differentiate between musicians with and without dystonia. 20 right-handed professional musicians (11 with dystonia) generated isometric flexion forces with the instructed finger to match 25%, 50% or 75% of maximal voluntary contraction for that finger. Enslaving was estimated as a linear slope of the forces applied across all instructed/uninstructed finger combinations. Musicians with dystonia had a small but robust loss of finger dexterity. There was increased enslaving and mirroring, primarily during use of the symptomatic hand (enslaving p = 0.003; mirroring p = 0.016), and to a lesser extent with the asymptomatic hand (enslaving p = 0.052; mirroring p = 0.062). Increased enslaving and mirroring were seen across all combinations of finger pairs. In addition, enslaving was exaggerated across symptomatic fingers when more than one finger was clinically affected. Task-specific dystonia therefore appears to express along a gradient, most severe in the affected skill with subtle and general motor control dysfunction in the background. Recognition of this provides a more nuanced understanding of the sensorimotor control deficits at play and can inform therapeutic options for this highly disabling disorder.