Faculty Bibliography

Apathy is one of the most prevalent and disabling non-motor symptoms in Parkinson's disease (PD) and dementia with Lewy bodies (DLB), collectively referred to as Lewy body disorders (LBDs). It is associated with reduced quality of life, accelerated cognitive decline, increased caregiver burden, and poorer functional outcomes, yet remains underrecognized and undertreated. A Working Group of the International Parkinson and Movement Disorder Society's Non-Motor Symptoms Study Group conducted a comprehensive review of the literature and developed a position paper through iterative expert discussion and critical appraisal of available data. This review aims to provide a structured, expert-informed synthesis of the current evidence on the clinical features, neurobiology, assessment, and management of apathy in LBDs and to define priorities for future research and clinical trials. Apathy in LBDs is a multidimensional syndrome encompassing reward insensitivity, negative affect, executive dysfunction, and auto-activation deficits. Converging evidence implicates dysfunction within distributed frontal-striatal-limbic networks and multi-neurotransmitter systems, including dopaminergic, serotonergic, noradrenergic, and cholinergic pathways. Although several pharmacological and nonpharmacological interventions have been explored, few randomized controlled trials have specifically targeted apathy, and no treatment can currently be considered definitively efficacious. Methodological heterogeneity, inadequate phenotyping, and inconsistent outcome measures have limited therapeutic progress. Apathy should be recognized as a primary clinical and research priority in LBDs. Future adequately powered, mechanistically informed trials using standardized diagnostic criteria and validated outcome measures are urgently needed to advance treatment development. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Degeneration of the central autonomic network with relative sparing of peripheral autonomic neurons underlies neurogenic orthostatic hypotension in patients with multiple system atrophy (MSA). Ampreloxetine, a novel, selective, norepinephrine (NE) reuptake inhibitor, allows once-daily dosing to precisely target residual peripheral autonomic neurons. Based on the hypothesis that patients with MSA would be most responsive and the substantial unmet need for symptomatic therapy in this population, an MSA subgroup analysis was prespecified. METHODS:We conducted a run-in 4-week, parallel-group, randomized controlled trial (SEQUOIA), followed by a pivotal enriched randomized withdrawal (RW) trial with 16-week open-label treatment and 6 weeks of 1:1 RW (REDWOOD). Inclusion criteria for the MSA subgroup included (1) probable or possible MSA, (2) 3-minute orthostatic blood pressure (BP) fall >20/10 mm Hg, and (3) dizziness or lightheadedness score >4 points. Outcome measures included self-reported symptom burden captured on the 10-item OH Questionnaire (OHQ). Differences were analyzed using logistic regression and mixed-model repeated measures analysis. RESULTS:= 0.015). Standing BP remained unchanged from open-label in the ampreloxetine group (systolic: 5.6 ± 4.1; diastolic: 3.7 ± 2.9 [SE] mm Hg) but fell after placebo withdrawal (systolic: -10.0 ± 4.5; diastolic: -6.0 ± 3.1 mm Hg). The catecholamine profile was consistent with NE transporter inhibition. There were no observed increases in supine BP. DISCUSSION/CONCLUSIONS:In a prespecified subgroup analysis of MSA participants in the REDWOOD trial, patients randomized to placebo worsened, whereas those who were randomized to treatment maintained their open-label level of function. TRIAL REGISTRATION INFORMATION/UNASSIGNED:REDWOOD trial, NCT03829657; first submitted to registry January 10, 2019; first participant enrolled February 22, 2019. SEQUOIA trial, NCT03750552; first submitted to registry November 20, 2018; first participant enrolled January 24, 2019. See ClinicalTrials.gov for full-protocol and statistical analysis plan. CLASSIFICATION OF EVIDENCE/METHODS:This study provides Class III evidence that in patients with MSA who had symptomatic benefit on orthostatic hypotension with ampreloxetine, there was no difference in the odds of treatment failures between those maintained on ampreloxetine and those withdrawn to placebo.

BACKGROUND:The Movement Disorder Society (MDS) research criteria for possible prodromal multiple system atrophy (PP-MSA) have not been prospectively validated. OBJECTIVE:To evaluate the diagnostic performance of the PP-MSA criteria in a longitudinal cohort of patients with pure autonomic failure (PAF) and to assess whether additional clinical features improve their predictive value. METHODS:Seventy-six patients with PAF enrolled across eight centers in the Natural History Study of the Synucleinopathies were followed for ≥6 years or until phenoconversion. Participants were classified according to MDS PP-MSA criteria and followed for development of MSA, Parkinson's disease, or dementia with Lewy bodies. Diagnostic performance was assessed longitudinally. Analyses were repeated using a stricter olfactory threshold (University of Pennsylvania Smell Identification Test [UPSIT]≤28) as an exclusion criterion. RESULTS:Thirty-eight participants met PP-MSA criteria, of whom 12 phenoconverted to MSA within 6 years. Sensitivity was 100% at year 1 and 92% at year 6, whereas specificity ranged from 56% to 67%. Positive predictive value (PPV) ranged from 21% to 34%. Applying a stricter olfactory threshold improved specificity (90%-97%) and PPV (53%-83%), with a modest reduction in sensitivity (to 83%). Participants who phenoconverted to MSA were younger, had more severe urinary dysfunction, and greater orthostatic heart rate responses. CONCLUSIONS:The PP-MSA criteria demonstrate high sensitivity but limited specificity in patients with PAF. A stricter olfactory threshold improves diagnostic performance and may enhance cohort enrichment for clinical trials. © 2026 International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

PURPOSE/OBJECTIVE:To review the cardiovascular effects of pharmacologic dopamine receptor modulation in humans, organized by receptor subtype. METHODS:Narrative review of human pharmacological, genetic, and clinical evidence linking dopamine receptor agonism and antagonism to blood pressure and heart rate changes in healthy volunteers and in patients with Parkinson disease, autonomic failure, psychiatric disorders, and selected cardiovascular conditions. RESULTS:Dopaminergic receptor agonism generally lowers blood pressure, with the magnitude of hypotension tracking with intrinsic activity: full orthosteric agonists (bromocriptine, ropirinole, apomorphine) carry the highest risk of orthostatic hypotension, and partial agonists (tavapadon) produce attenuated but clinically relevant hypotension. Dopamine D3-preferring agents (PF-592379, mesdopetam, cariprazine) have neutral cardiovascular effects in short-term trials. Levodopa-induced orthostatic hypotension arises from at least five converging mechanisms whose clinical impact is amplified by underlying neurogenic orthostatic hypotension. A notable exception is mevidalen, a centrally acting dopamine D1 positive allosteric modulator that paradoxically raises blood pressure. Despite murine knockout models consistently predicting that dopamine receptor deletion produces hypertension, pharmacological antagonism in humans does not reliably raise blood pressure: dopamine D1, D2, and D3 antagonists show largely neutral cardiovascular profiles, while antipsychotic-associated orthostatic hypotension is driven primarily by α1-adrenergic blockade. CONCLUSIONS:The cardiovascular response to dopaminergic agents depends on receptor selectivity, intrinsic activity, and baroreflex integrity. The discrepancy between murine-knockout-predicted hypertension and human pharmacological neutrality with antagonists, and the hypertensive effects of dopamine D1 positive allosteric modulators, represent key unresolved questions.

BACKGROUND/UNASSIGNED:The long-term efficacy and safety of vutrisiran in hereditary transthyretin amyloidosis with polyneuropathy (ATTRv-PN) were assessed in the HELIOS-A randomized treatment extension (RTE). METHODS/UNASSIGNED:Patients who completed the 18-month, phase 3, open-label HELIOS-A study could enter an open-label RTE with re-randomization 1:1 to vutrisiran 25 mg every 3 months (Q3M) or 50 mg every 6 months (Q6M; transitioned to 25 mg Q3M following an amendment) for up to 42 months (RTE M18 efficacy assessment; RTE M42 safety and transthyretin (TTR) levels). RESULTS/UNASSIGNED: = 73]). Mean serum TTR reduction from study baseline at RTE M42 for the total vutrisiran group was 84.5%. Efficacy was sustained from RTE baseline through RTE M18 in modified Neuropathy Impairment Score +7, Norfolk Quality of Life-Diabetic Neuropathy score, 10-meter walk test, Rasch-built Overall Disability Scale and modified body mass index (mBMI); most patients (67.8%) had stable polyneuropathy disability scores. Most AEs were mild/moderate in severity with no new safety concerns. CONCLUSIONS/UNASSIGNED:Results from the HELIOS-A RTE demonstrate relative stability with only modest changes in disease activity, sustained serum TTR reductions, and an acceptable safety profile with long-term vutrisiran treatment in patients with ATTRv-PN. UNLABELLED:ClinicalTrials.gov: NCT03759379.

Patients with extremely rare pathogenic variants pose unique challenges to current healthcare systems. Nano-rare mutations have been defined as mutations with a known prevalence of <30 patients worldwide, but because of the small fraction of humans who have undergone genetic testing, neither the precise prevalence of individual mutations nor the total prevalence of patients with nano-rare mutations is known. n-Lorem is a non-profit founded in 2020 with the mission of equitably discovering, developing, and providing bespoke experimental antisense oligonucleotides (ASOs) for free, for life, to patients with nano-rare mutations that are amenable to ASO treatment. In this perspective, we provide an overview of the n-Lorem processes and systems, the characteristics of the first 329 patients who have applied for treatment for whom initial assessment was completed and suitability for ASO treatment determined, and a summary of the results of ASO treatment for patients treated to date. Detailed data on individual patients and the overall clinical safety and tolerability profiles of the ASOs for which there are clinical data are the subjects of other manuscripts.

Human pluripotent stem cells (hPSCs) are a valuable tool for disease modeling. Further stem cells can be reprogrammed from adult somatic cells, called induced pluripotent stem cells (iPSC). iPSC technology allows for the evaluation of specific study participants and populations and ventures into personalized medicine. Blood is routinely taken and cryopreserved for research purposes. These samples are processed either as buffy coats, a blood sample containing white blood cells and platelets, or as peripheral blood mononuclear cells (PBMCs), which represent a more purified population of white blood cells without eosinophils, basophils, platelets, or red blood cells. Both are a readily available and relatively non-invasive source for reprogrammable somatic cells. Several reports detail reprogramming from PBMCs, whereas only one describes this process from frozen buffy coats. Recent experience revealed PBMC reprogramming protocols available in the literature and from manufacturers to be unsuccessful when applied to frozen buffy coat samples, necessitating the adaptations and troubleshooting strategies described here. For many researchers, who employ iPSC technologies, it is imperative to have thorough protocols with a high success rate, especially in cases, where patient samples may contain only few cells, are obtained in wide time intervals, are from limited participant pool, or are otherwise highly valuable. Here, checkpoints and troubleshooting strategies are identified to increase the chance of reprogramming human frozen buffy coats or purified PBMCs. Ultimately, this protocol will allow researchers to identify predictors of reprogramming success and strategize alternative approaches to improve the chances of successful iPSC derivation.

PURPOSE/OBJECTIVE:The Unified Multiple System Atrophy Rating Scale (UMSARS) is widely used as an outcome measure in MSA trials, but it has limitations for clinical trial use. To address these, we developed the Multiple System Atrophy Combined Outcome Assessment (MuSyCA), a comprehensive multimodal tool for disease-modifying MSA trials. The purpose of this manuscript is to describe the development and validation plan for MuSyCA, with emphasis on its structure, intended use, and assessment of reliability, validity, and sensitivity in tracking disease progression. METHODS:The development of MuSyCA followed a multistep process. Candidate outcome assessments were identified through systematic literature review and analysis of longitudinal data from large MSA cohorts. Content was refined through multiple Delphi-like consensus rounds involving MSA experts, patient advocacy groups representatives, and industry stakeholders. Cognitive interviews conducted in 20  patients with MSA evaluated the clarity and clinical relevance of patient- and clinician-reported outcomes; feedback was incorporated into a subsequent version of the MuSyCA. Validation is ongoing and includes assessment of construct validity, internal consistency, test-retest reliability, and responsiveness. Longitudinal analyses to determine sensitivity to change over time are ongoing. RESULTS:MuSyCA combines patient- and clinician-reported outcomes, biomarkers (neurofilament light chain, neuroimaging), and performance-based measures to capture subjective and objective aspects of MSA progression, enhancing its utility  to detect treatment effects in clinical trials. MuSyCa is not intended to be used in clinical practice. CONCLUSIONS:MuSyCA offers a multidimensional approach to MSA assessment, supporting precise, disease-relevant evaluations in trials of putative disease-modifying therapies. Its validation will provide a standardized multimodal outcome measure, advancing MSA therapeutic development.

OBJECTIVE:To determine the test performance of cutaneous phosphorylated alpha-synuclein (P-SYN) in dementia with Lewy bodies (DLB), individuals with reduced Montreal Cognitive Assessment (MoCA) and healthy controls. METHODS:This is the first subgroup analysis of the Synuclein-One study, a prospective, blinded study evaluating P-SYN detection from skin biopsies in 218 subjects with a referral diagnosis of control (N = 151) and DLB (N = 67). All subjects completed detailed examinations, questionnaires, and had skin biopsies for detection of P-SYN. DLB patients were included if meeting the 4th DLB consensus probable criteria. Control subjects, aged 40-99, had no history, examination findings, or symptoms suggestive of a synucleinopathy or neurodegenerative disease. An expert review panel, blinded to pathological data, determined the final diagnosis. Controls with reduced MoCA (MoCA < 26, N = 26) at screening were analyzed separately. RESULTS:After expert panel review, only 50/67 patients met consensus criteria for DLB, 26/151 controls had a reduced MoCA, and 120/151 controls had a normal MoCA. The proportions of subjects with cutaneous P-SYN detected by skin biopsy were 96.0% (48 of 50) of the DLB group, 31% (8 of 26) of the controls with reduced MoCA, and 3.3% (4 of 120) of the controls with normal MoCA. INTERPRETATION/CONCLUSIONS:In this prospective, blinded, cross-sectional study, a high proportion of subjects meeting clinical consensus criteria for DLB had P-SYN detected in skin biopsies. Almost 1/3 of subjects with reduced MoCA testing also had P-SYN detected. These results support a role for skin biopsy detection of P-SYN in patients with DLB. TRIAL REGISTRATION/BACKGROUND:NCT04700722.