Tröster, Alexander I.

Importance The Implantable Neurostimulator for the Treatment of Parkinson’s Disease (INTREPID) trial was a randomized, double-blind, sham-controlled study of subthalamic nucleus (STN) deep brain stimulation (DBS) for the treatment of Parkinson disease (PD). Objective To evaluate the long-term (5-year) outcomes and safety of STN-DBS for PD. Design, Setting, and Participants This was a prospective, randomized (3:1), 12-week double-blind sham-controlled study at 23 movement disorder centers across the US with an open-label 5-year follow-up. Patients were implanted and followed up with the Vercise DBS system from May 2013 to December 2022. Eligibility required diagnosis of bilateral idiopathic PD with more than 5 years of motor symptoms, more than 6 hours per day of poor motor function, modified Hoehn and Yahr Scale scores higher than 2, Unified Parkinson’s Disease Rating Scale (UPDRS-III) score of 30 or higher (medication-off state), and 33% or higher improvement in UPDRS-III medication-on score. Intervention Bilateral STN-DBS for moderate to advanced PD. Main Outcomes and Measures Primary outcomes included changes in UPDRS and dyskinesia scores, quality-of-life measures, and safety assessments. Exploratory analyses included medication reduction and DBS association with motor signs. Results A total of 313 patients were enrolled with 191 receiving the DBS system, and 137 participants (72%) completed the study. The study population had a mean (SD) age of 60 (7.9) years, with 139 (73%) male participants. Motor function without medication as measured by UPDRS-III improved from a mean (SD) of 42.8 (9.4) to 21.1 (10.6) at year 1 (51%; 95% CI, 49%-53%; P < .001) and 27.6 (11.6) at year 5 (36%; 95% CI, 33%-38%; P < .001). Activities of daily living without medication as measured by UPDRS-II improved from a mean (SD) of 20.6 (6.0) to 12.4 (6.1) at year 1 (41%; 95% CI, 38%-42%; P < .001) and 16.4 (6.5) at year 5 (22%; 95% CI, 18%-23%; P < .001). Dyskinesia scores decreased from 4.0 (5.1) to 1.0 (2.1) at year 1 (75%; 95% CI, 73%-75%; P < .001) and to 1.2 (2.1) at year 5 (70%; 95% CI, 63%-75%; P < .001). The levodopa equivalent dose was reduced by 28% at year 1, remaining stable at year 5 (28%; 95% CI, 26%-31%; P < .001). The most common serious adverse event was infection (9 participants). Ten deaths were reported, none related to the study. Conclusions and Relevance Although STN-DBS outcomes declined slightly, possibly due to the progressive nature of the disease, patients with PD sustained significant improvement in motor and activities of daily living scores, along with a stable reduction in anti-parkinsonian medication over the 5-year follow-up period.

ABSTRACTBackgroundThe criteria for PD‐MCI allow the use of global cognitive tests. Their predictive value for conversion from PD‐MCI to PDD, especially compared to comprehensive neuropsychological assessment, is unknown.MethodsThe MDS PD‐MCI Study Group combined four datasets containing global cognitive tests as well as a comprehensive neuropsychological assessment to define PD‐MCI (n = 467). Risk for developing PDD was examined using a Cox model. Global cognitive tests were compared to neuropsychological test batteries (Level I&II) in determining risk for PDD.ResultsPD‐MCI based on a global cognitive test (MMSE or MoCA) increases the hazard for developing PDD (respectively HR = 2.57, P = 0.001; HR = 4.14, P = <0.001). The C‐statistics for MMSE (0.72) and MoCA (0.70) were lower than those based on neuropsychological tests (Level I = 0.82; Level II = 0.81). Sensitivity, specificity and diagnostic accuracy balance was best in Level II.ConclusionMMSE and MoCA predict conversion to PDD. However, Level II neuropsychological assessment seems the preferred assessment for PD‐MCI.

AbstractBackgroundThe International Parkinson and Movement Disorders Society criteria for mild cognitive impairment in PD need validation. The objectives of this present study were to evaluate prognostic validity of level I (abbreviated) International Parkinson and Movement Disorders Society mild cognitive impairment in PD criteria for development of PD dementia and compared them with level II (comprehensive) criteria.MethodsWe analyzed data from 8 international studies (1045 patients) from our consortium that included baseline data on demographics, motor signs, depression, detailed neuropsychological testing, and longitudinal follow‐up for conversion to Parkinson's disease dementia. Survival analysis evaluated their contribution to the hazard of Parkinson's disease dementia.ResultsLevel I mild cognitive impairment in PD, increasing age, male sex, and severity of PD motor signs independently increased the hazard of Parkinson's disease dementia. Level I and level II mild cognitive impairment in PD classification had similar discriminative ability with respect to the time to Parkinson's disease dementia.ConclusionsLevel I mild cognitive impairment in PD classification independently contributes to the hazard of Parkinson's disease dementia. This finding supports the prognostic validity of the abbreviated mild cognitive impairment in PD criteria. © 2019 International Parkinson and Movement Disorder Society

AbstractBackground: Numerous neuropsychological tests and test versions are used in Parkinson's disease research, but their relative capacity to detect mild cognitive deficits and their comparability across studies are unknown. The objective of this study was to identify neuropsychological tests that consistently detect cognitive decline in PD across studies.Methods: Data from 30 normed neuropsychological tests across 20 international studies in up to 2908 nondemented PD patients were analyzed. A subset of 17 tests was administered to up to 1247 healthy controls. A 2‐step meta‐analytic approach using standardized scores compared performance in PD with normative data.Results: Pooled estimates of the differences between PD and site‐specific healthy controls identified significant cognitive deficits in PD patients on 14 test scores across 5 commonly assessed cognitive domains (attention or working memory, executive, language, memory, and visuospatial abilities), but healthy control performance was statistically above average on 7 of these tests. Analyses based on published norms only, as opposed to direct assessment of healthy controls, showed high between‐study variability that could not be accounted for and led to inconclusive results.Conclusions: Normed neuropsychological tests across multiple cognitive domains consistently detect cognitive deficits in PD when compared with site‐specific healthy control performance, but relative PD performance was significantly affected by the inclusion and type of healthy controls versus the use of published norms only. Additional research is needed to identify a cognitive battery that can be administered in multisite international studies and that is sensitive to cognitive decline, responsive to therapeutic interventions, and superior to individual cognitive tests. © 2018 International Parkinson and Movement Disorder Society

ABSTRACT Background The International Parkinson and Movement Disorder Society criteria for mild cognitive impairment in PD were recently formulated. Objectives The aim of this international study was to evaluate the predictive validity of the comprehensive (level II) version of these criteria by assessment of their contribution to the hazard of PD dementia. Methods Individual patient data were selected from four separate studies on cognition in PD that provided information on demographics, motor examination, depression, neuropsychological examination suitable for application of level II criteria, and longitudinal follow‐up for conversion to dementia. Survival analysis evaluated the predictive value of level II criteria for cognitive decline toward dementia as expressed by the relative hazard of dementia. Results A total of 467 patients were included. The analyses showed a clear contribution of impairment according to level II mild cognitive impairment criteria, age, and severity of PD motor symptoms to the hazard of dementia. There was a trend of increasing hazard of dementia with declining neuropsychological performance. Conclusions This is the first large international study evaluating the predictive validity of level II mild cognitive impairment criteria for PD. The results showed a clear and unique contribution of classification according to level II criteria to the hazard of PD dementia. This finding supports their predictive validity and shows that they contribute important new information on the hazard of dementia, beyond known demographic and PD‐specific factors of influence. © 2017 International Parkinson and Movement Disorder Society

Abstract Background: The etiology and natural history of Parkinson’s disease (PD) are not well understood. Some non-motor symptoms such as hyposmia, rapid eye movement sleep behavior disorder, and constipation may develop during the prodromal stage of PD and precede PD diagnosis by years. Objectives: We examined the promise and pitfalls of research on premotor symptoms of PD and developed priorities and strategies to understand their clinical and etiological implications. Methods: This review was based on a workshop, Parkinson’s Disease Premotor Symptom Symposium, held 7–8 June 2012 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. Discussion: Research on premotor symptoms of PD may offer an excellent opportunity to characterize high-risk populations and to better understand PD etiology. Such research may lead to evaluation of novel etiological hypotheses such as the possibility that environmental toxicants or viruses may initiate PD pathogenesis in the gastrointestinal tract or olfactory bulb. At present, our understanding of premotor symptoms of PD is in its infancy and faces many obstacles. These symptoms are often not specific to PD and have low positive predictive value for early PD diagnosis. Further, the pathological bases and biological mechanisms of these premotor symptoms and their relevance to PD pathogenesis are poorly understood. Conclusion: This is an emerging research area with important data gaps to be filled. Future research is needed to understand the prevalence of multiple premotor symptoms and their etiological relevance to PD. Animal experiments and mechanistic studies will further understanding of the biology of these premotor symptoms and test novel etiological hypothesis. Citation: Chen H, Burton EA, Ross GW, Huang X, Savica R, Abbott RD, Ascherio A, Caviness JN, Gao X, Gray KA, Hong JS, Kamel F, Jennings D, Kirshner A, Lawler C, Liu R, Miller GW, Nussbaum R, Peddada SD, Comstock Rick A, Ritz B, Siderowf AD, Tanner CM, Tröster AI, Zhang J. 2013. Research on the premotor symptoms of Parkinson’s Disease: clinical and etiological implications. Environ Health Perspect 121:1245–1252; http://dx.doi.org/10.1289/ehp.1306967