Christopher G. Goetz

Background: The sum of clinician‐rated MDS‐UPDRS Part III Motor Examination items is widely used in Parkinson's disease (PD), but item‐ or subset prognostic value remains unclear. Whereas reduced subsets of patient‐reported Parts IB + II show improved utility for predicting time to PD medication initiation, the validity of similar Part III subsets is unknown. Objectives: Determine whether a subset of MDS‐UPDRS Part III items is superior in prognostic value to the full scale for time to PD medication initiation in early disease. Methods: Harmonized longitudinal data from six early PD cohorts, with time to PD medication initiation as the primary outcome, were analyzed using a longitudinal item response theory model to rank items, combining discrimination and information. Rank‐driven cumulative subsets were formed to analyze the primary outcome using time‐varying Cox models under clinically relevant follow‐up windows. Subset performance was assessed using the C‐index and compared with the full‐item model using Wald tests. Successful item reduction required stable, significant improvement across all follow‐up windows. Results: No item subset met the predefined criteria for stable and superior prognostic performance relative to the full Part III scale. Best reduced‐subset versus full‐model C‐indices were similar and non‐significant: 0.582 versus 0.581 under full follow‐up, 0.602 versus 0.602 at 1 year, and 0.586 versus 0.585 at 2 years. Conclusions: Unlike Parts IB and II, no sensitivity‐driven reduced subset significantly and consistently outperformed the full MDS‐UPDRS Part III in predicting time to PD medication initiation in early PD, not supporting a reduction of the 33‐item scale in this setting.

Background: Individuals with Parkinson's disease (PD) carrying GBA1 variants often develop advanced motor complications that prompt evaluation for deep brain stimulation (DBS). However, concerns about accelerated cognitive decline after DBS in GBA1 carriers complicate clinical decision making. A critical aspect that is increasingly gaining attention is the time at which DBS is performed. Objective: The objective is to determine how the timing of DBS in relation to PD onset impacts cognitive trajectories across different GBA1 variant classes and in individuals without GBA1 variants. Methods: A multicenter cohort study across 10 study sites in Europe and the USA was conducted. The study population comprised subjects with ( GBA1 ‐Associated Parkinson's Disease [GBA‐PD]) and without GBA1 variants (nonGBA‐PD), who were subjected to bilateral subthalamic nucleus (STN)‐DBS. The main outcome measure was the Mattis Dementia Rating Scale (MDRS). Results: A total of 343 individuals (91 GBA‐PD and 252 nonGBA‐PD) were included in this study. Percentile‐based stratification into early and late STN‐DBS treatment groups and linear mixed model analyses revealed that GBA‐PD patients in the late DBS group had a significantly faster rate of cognitive decline independent of age, with sensitivity analyses identifying the 7‐ and 8‐year cutoffs as the time points with a significant difference between early and late STN‐DBS groups in GBA‐PD. A negative correlation between MDRS scores and time from disease onset to STN‐DBS was observed in GBA‐PD, and was not present in nonGBA‐PD. Cognitive trajectories were markedly worse in GBA‐PD compared to nonGBA‐PD, and this pattern was not influenced by the variant type. Conclusions: In GBA‐PD, STN‐DBS treatment at later stages is associated with greater risk of cognitive decline. Earlier STN‐DBS intervention in GBA‐PD may extend the period of improved motor function before the onset of significant cognitive decline. These findings highlight the potential importance of early genetic testing and disease duration when considering STN‐DBS in genetically defined PD populations. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Background: Cervical dystonia (CD) motor severity is typically quantified with the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS). An expanded version of the Motor Severity section of the TWSTRS (“TWSTRS‐Delphi”) has been previously evaluated for its clinimetric properties but not for inter‐ and intrarater reliability. Objective: In this study we quantified inter‐ and intrarater reliability of the Motor Severity section of the TWSTRS‐Delphi for CD. Methods: Ten raters familiar with the TWSTRS‐Delphi and ten raters unfamiliar with it independently scored standardized videos from 90 patients with CD. We computed one‐way random intraclass correlation coefficient (ICC, absolute agreement) for total and item scores. We repeated assessments and calculations with a subset of raters to assess intrarater reliability. Results: Interrater reliability for the Total score was good for Familiar raters (ICC = 0.697) and fair for Unfamiliar raters (ICC = 0.566). Most individual items achieved fair–excellent interrater agreement in both groups (Familiar 0.415–0.763; Unfamiliar 0.416–0.769). Sagittal Shift, Duration, and Sensory Tricks showed poor agreement. Intrarater reliability was fair–excellent for most items in both groups (Familiar 0.494–0.927; Unfamiliar 0.413–0.877), but poor for Sagittal Shift and Duration among Familiar raters. Conclusions: The TWSTRS‐Delphi yields reproducible Total and item scores across movement disorder raters. The data pinpoint Sagittal Shift, Duration, and Sensory Tricks as the principal sources of between‐rater variability, defining immediate priorities for scale modification and focused training.

In 2025, international neurology celebrates the bicentenary of J.-M. Charcot's birth. As a major medical scientist in Paris and the founder of modern clinical neurology, Charcot became friends with...

Objective: To honor the bicentenary of Jean‐Martin Charcot's birth and to consolidate the primary materials from a historical exhibit on the topic at the 2025 International Parkinson and Movement Disorder Congress, this article aims to provide an overview of Charcot's place in the context of 21st century movement disorders neurology. Background: Charcot (1825–1893) is largely considered the Father of Clinical Neurology, having established the basic discipline of anatomo‐clinical correlations in brain and spinal cord disease. His contributions to movement disorders neurology were seminal and remain as anchors of 21st century neurological study. Methods: Original and secondary sources from international archives and collections served as the material for study and interpretation. Results: Charcot fundamentally contributed to the clinical descriptions of Parkinson's disease, other parkinsonian syndromes, tremor conditions, tic disorders and chorea. Whereas he performed extensive neuroanatomical studies, he classified most movement disorders as névroses, conditions with undetected structural lesions yet to be defined. Conclusions: Charcot developed a clear classification system for movement disorders that largely remains intact today. He developed a French School of Neurology of both historical and modern fame, and, in introducing the model of an academic clinical hospital research center as multidimensional integration of clinical care, research, and education, he left a legacy that remains the model of the 21st century neurological research center.

Clinical neuroscience focuses on the mechanisms of brain function, but this approach falls short of insights into how the central nervous system (CNS) evolved, both in health and disease. Here, we discuss evolutionary concepts relevant to understanding human brain diseases, on the genetic, subcellular, cellular, connectomic, behavioral, and cultural levels. By revisiting common neurological diseases, we discuss evolved residues from our ancestors, mechanisms of exaptation, antagonistic pleiotropy, and human longevity with the consequent outpacing of biological evolution by cultural evolution. An evolution‐based conceptual framework can propel transdisciplinary research targeting the constraints imposed by and compensatory adaptations involved in human‐specific neurological diseases. ANN NEUROL 2025;98:1178–1195

Background: Telemedicine has improved access to care, yet device usage for virtual visits remains underexplored. Objective: To characterize device usage patterns for video televisits across sociodemographic factors in a tertiary Movement Disorders clinic in the United States. Methods: We conducted a three‐year retrospective cross‐sectional analysis of 2181 video televisits, categorizing devices used as mobile (smartphones/tablets) or personal computers (desktops/laptops), and analyzed usage patterns across age, sex, race, and income. Results: Mobile devices were used in 88% of video televisits. Patients p = 0.002). Lower income patients used only mobile devices. Significant differences were detected for age and income, but effect sizes were small. Logistic regression identified only age p = 0.0005). Conclusions: Mobile device usage for telemedicine is becoming increasing ubiquitous across sociodemographic factors, highlighting the need to optimize mobile telemedicine platforms and leverage mobile devices for teleresearch in Movement Disorders patients.