Risk of Parkinson's disease dementia related to level I MDS PD-MCI.

BACKGROUND: The 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. METHODS: We 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. RESULTS: Level 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. CONCLUSIONS: Level 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.

Initial cognitive changes in Parkinson's disease.

The focus on cognitive impairment in neurodegenerative diseases, including PD, is shifting from the dementia stage to earlier stages of impairment, including mild cognitive impairment. This shift is driven primarily by the desire to improve long-term outcomes by delivering therapeutic interventions earlier in the clinical course, even presymptomatically in those at highest risk, and at the initial stage in the pathophysiological cascade that underpins common dementia syndromes. This article focuses on key findings and challenges in studying earliest stages of cognitive decline in PD, including a detailed examination of neuropsychological testing, cognitive performance in early and prodromal PD, epidemiological research for PD mild cognitive impairment to date, and expert recommendations for assessment. © 2018 International Parkinson and Movement Disorder Society.

Strengths and challenges in conducting clinical trials in Parkinson's disease mild cognitive impairment.

Treatments to slow the progression of cognitive dysfunction to dementia and improve the quality of life of persons with Parkinson's disease (PD) are desperately needed. Because PD mild cognitive impairment is considered a transitional stage before dementia, it opens a window to timely intervention. This article critically reviews the strengths and challenges of pharmacologic and nonpharmacologic clinical therapeutic trials in PD mild cognitive impairment conducted during the past 5 years, including ongoing trials. Relatively few high-quality trials have been conducted, and some important factors in designing future clinical trials are discussed. © 2018 International Parkinson and Movement Disorder Society.

Detecting Mild Cognitive Deficits in Parkinson's Disease: Comparison of Neuropsychological Tests.

BACKGROUND: 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.

Cognitive outcome after ventral capsule/ventral striatum stimulation for treatment-resistant major depression.

BACKGROUND: We report the neuropsychological outcome of 25 patients with treatment-resistant major depressive disorder (TRD) who participated in an Institutional Review Board (IRB)-approved randomised double-blind trial comparing active to sham deep brain stimulation (DBS) in the anterior limb of the ventral capsule/ventral striatum (VC/VS). METHODS: Participants were randomised to active (n=12) versus sham (n=13) DBS for 16 weeks. Data were analysed at the individual and group levels. Group differences were analysed using repeated measures ANOVAs. Relationships between depression severity and cognition were examined using partial correlations. The false discovery rate method controlled for multiple analyses. RESULTS: No significant interactions comparing active versus sham stimulation over time were evident. Change in depression was unrelated to change in neuropsychological measures. Twenty patients declined by ≥1 SD on at least one measure (41.3% of declines occurred in active group participants; 63.0% in older participants regardless of stimulation status). Twenty-two patients exhibited improvements >1 SD on neuropsychological measures (47.7% in the active group; 63.1% in younger participants). CONCLUSIONS: These data suggest that VC/VS DBS in patients with TRD does not significantly affect neuropsychological function. Age at surgery, regardless of stimulation status, may be related to cognitive outcome at the individual patient level. TRIAL REGISTRATION NUMBER: NCT00837486; Results.

Neuropsychological outcomes from constant current deep brain stimulation for Parkinson's disease.

OBJECTIVE: The aim of this study was to evaluate the neurobehavioral safety of constant-current subthalamic deep brain stimulation and to compare the neuropsychological effects of stimulation versus electrode placement alone. METHODS: A total of 136 patients with Parkinson's disease underwent bilateral subthalamic device implantation in this randomized trial. Patients received stimulation either immediately after device implantation (n = 101; active stimulation) or beginning 3 months after surgery (n = 35; delayed activation control). Patients were administered neuropsychological tests before, 3, and 12 months after device implantation. RESULTS: Neuropsychological change in stimulation and control groups were comparable. Within-group analyses revealed declines in category and switching verbal fluency in both groups, but only the stimulation group had letter verbal fluency and Stroop task declines. Depression symptom improvements occurred in both groups, but more often in the stimulation group. Letter fluency declines were associated with worse Parkinson's Disease Questionnaire Communication subscale scores. Baseline and 12-month comparisons (in the combined group) revealed gains in verbal and visual delayed recall scores and improvement in depression symptoms, but decrements in verbal fluency and Stroop scores. CONCLUSIONS: Constant-current bilateral subthalamic stimulation had a good cognitive safety profile except for decrements in verbal fluency and on the Stroop task. These abnormalities are related to device implantation, but stimulation likely had an additive effect. One year after surgery, the cognitive changes did not exert a detrimental effect on quality of life, although letter fluency declines were associated with communication dissatisfaction at 12 months. Improvement in depressive symptom severity appears dependent on stimulation and not placebo or lesion effects. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Mild cognitive impairment as a risk factor for Parkinson's disease dementia.

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.

The Neuropsychology of Movement and Movement Disorders: Neuroanatomical and Cognitive Considerations.

This paper highlights major developments over the past two to three decades in the neuropsychology of movement and its disorders. We focus on studies in healthy individuals and patients, which have identified cognitive contributions to movement control and animal work that has delineated the neural circuitry that makes these interactions possible. We cover advances in three major areas: (1) the neuroanatomical aspects of the "motor" system with an emphasis on multiple parallel circuits that include cortical, corticostriate, and corticocerebellar connections; (2) behavioral paradigms that have enabled an appreciation of the cognitive influences on the preparation and execution of movement; and (3) hemispheric differences (exemplified by limb praxis, motor sequencing, and motor learning). Finally, we discuss the clinical implications of this work, and make suggestions for future research in this area. (JINS, 2017, 23, 768-777).

Accuracy of Patient and Care Partner Identification of Cognitive Impairments in Parkinson's Disease-Mild Cognitive Impairment.

BACKGROUND: Criteria for Parkinson's disease-mild cognitive impairment require a caregiver or patient complaint or clinician observation of cognitive decline and objective evidence of cognitive deficit in at least 1 of 5 cognitive domains. This study examines the accuracy of Parkinson's disease-mild cognitive impairment patient and care partner reports of specific cognitive difficulties. METHODS: A total of 42 Parkinson's disease-mild cognitive impairment patients and their care partners reported the absence or presence of deficits in each cognitive domain during an interview. A deficit in each domain was defined by scores ≤ 1.5 standard deviations below the mean on corresponding cognitive tests. RESULTS: Sensitivity, specificity, and positive and negative predictive values were modest for patient and care partner reports across all domains. Patients' and care partners' accuracy in observing objectively identified deficits was poor across all domains (≤ 60% agreement; κ ≤ .07). Patient and care partner reports showed moderate agreement in all domains except attention (≥ 74% agreement; κ ≥ .43). CONCLUSIONS: Parkinson's disease-mild cognitive impairment patients and their care partners may not be accurate in identifying specific cognitive deficits. Thus, even patients (and care partners) who correctly report having a cognitive deficit may misidentify the specific deficit. The finding supports the value of International Parkinson and Movement Disorder Society Parkinson's disease-Mild Cognitive Impairment Level II assessment and cautions against relying on subjective report or screening in research in which the nature of cognitive deficit identification or treatment is paramount. Overreliance on patient and care partner reports of specific impairments may distort epidemiologic estimates of mild cognitive impairment subtypes and misdirect cognitive rehabilitation at incorrect domains. © 2016 International Parkinson and Movement Disorder Society.

Validation of the QUEST for German-speaking countries.

OBJECTIVE: To explore the clinimetric attributes of the German version of the quality of life in essential tremor (ET) questionnaire (QUEST) as a tremor-specific measure of quality of life. METHODS: This was an observational, cross-sectional study. The QUEST German version was obtained by translation-back translation procedure. ET cases were diagnosed according to the tremor investigation group criteria. Assessments included Archimedes spirals rating, EQ-5D, Beck Depression Inventory (BDI-II) and QUEST German version. Missing data were imputed for those cases in which the loss of data for one domain of the QUEST was <30%. RESULTS: Ninety three patients out of 138 (67.4%) with definite or probable ET had complete QUEST data after 43 item imputations and they constituted the sample for this study. The QUEST summary index (QSI) displayed no floor or ceiling effects. QUEST internal consistency (Cronbach's alpha) ranged between 0.50 and 0.89. Item-total domain correlations ranged from 0.26 to 0.82 and the item homogeneity indexes were satisfactory (range: 0.28-0.60). The QSI correlated weakly with the EQ-5D (rS=0.20) and moderately with the BDI-II (rS = 0.31) and the QUEST self-evaluation of tremor severity (rS = 0.44). CONCLUSIONS: The QUEST German version has, despite recognized data quality problems, satisfactory acceptability and internal consistency as a whole. The correlation analysis showed that tremor in the head, voice and right hand was moderately associated with quality of life.

Proceedings of the Second Annual Deep Brain Stimulation Think Tank: What's in the Pipeline.

The proceedings of the 2nd Annual Deep Brain Stimulation Think Tank summarize the most contemporary clinical, electrophysiological, and computational work on DBS for the treatment of neurological and neuropsychiatric disease and represent the insights of a unique multidisciplinary ensemble of expert neurologists, neurosurgeons, neuropsychologists, psychiatrists, scientists, engineers and members of industry. Presentations and discussions covered a broad range of topics, including advocacy for DBS, improving clinical outcomes, innovations in computational models of DBS, understanding of the neurophysiology of Parkinson's disease (PD) and Tourette syndrome (TS) and evolving sensor and device technologies.

The tools of the trade: a state of the art "How to Assess Cognition" in the patient with Parkinson's disease.

Cognitive impairment in Parkinson's disease is heterogeneous both in severity and pattern and subject to influences both integral to and external to the disease. Diagnostic Criteria have been developed by the Movement Disorders Society that help to guide clinicians and researchers to an accurate diagnosis of Parkinson's disease - mild cognitive impairment or Parkinson's disease dementia. To operationalize these criteria, and to assess the pattern and severity of cognitive dysfunction we need: (1) Valid measures of cognitive abilities covering the major domains of cognition, (2) amethod to determine whether or not the performance represents a decline from a person's previous level of functioning, and (3) an assessment of how the individual's cognitive abilities enable (or disable) function in day to day activities. This paper will discuss the methods of assessment and the measures that can be used to make a comprehensive assessment of cognition in Parkinson's disease.

Neuropsychological outcomes after psychosocial intervention for depression in Parkinson's disease.

The authors describe neuropsychological outcomes in people with Parkinson's disease (PD) after their participation in an NIH-sponsored, randomized, controlled trial of cognitive-behavioral treatment for depression. Improvements in mood were associated with modest gains in verbal memory and executive functioning over the 10-week treatment period and accounted for greater variance in neuropsychological outcomes at the end of treatment than other known correlates of cognitive functioning in PD, such as disease severity, age, and education. Baseline working memory and executive skills were also associated with depression improvement over time.

Deep brain stimulation may improve quality of life in people with Parkinson's disease without affecting caregiver burden.

OBJECTIVE: This study aims to investigate the influence of deep brain stimulation (DBS) on caregiver burden and quality of life in Parkinson's disease. METHODS: A cross-sectional retrospective study utilizing the National Parkinson Foundation Quality Improvement Initiative clinical study was conducted. A group of 275 patients who had undergone DBS for Parkinson's disease were extracted from 2916 subjects who were included in this data base. The data were compared to an age, sex, and disease severity matched control group. A secondary analysis was then performed on two more control groups that were matched to account for presence or absence of motor fluctuations. The multidimensional caregiver strain index and Parkinson's disease quality-of-life questionnaire 39 summary index were compared. RESULTS: The multidimensional caregiver strain index did not differ between the DBS group (16.9 ± 11.8) and a matched non-DBS group (16.1 ± 17.6, p = 0.618). The quality-of-life index was, however, significantly better in the DBS group (28.9 ± 15.6) than in the non-DBS group (32.3 ± 17.6, p = 0.034). A secondary analysis revealed that the total caregiver strain score was lower in the no motor fluctuation control group than the other two groups (p < 0.05). Regression analysis revealed significant relationships between the quality-of-life index and caregiver strain index total scores (p < 0.001), between caregiver strain index total score and age at surgery (p = 0.027), and also between the interval since surgery (p = 0.048). CONCLUSIONS: Although there were several limitations to this study, DBS seems to improve quality of life without significantly increasing caregiver burden.

Developments in the prediction of cognitive changes following deep brain stimulation in persons with Parkinson's disease.

INTRODUCTION: Deep brain stimulation (DBS) is an effective treatment for Parkinson's disease (PD) motor symptoms that improves function and quality of life in appropriately selected patients. Because mild to moderate cognitive declines can follow DBS and impact quality of life in a minority of patients, an important consideration involves the cognitive deficit and its prediction. AREAS COVERED: The author briefly summarizes cognitive outcomes from DBS and reviews in more detail the risks/predictors of post-DBS cognitive dysfunction by mainly focusing on work published between 2018 and 2024 and using comprehensive neuropsychological (NP) evaluations. Most publications concern bilateral subthalamic nucleus (STN) DBS. Comment is offered on challenges and potential avenues forward. EXPERT OPINION: STN DBS is relatively safe cognitively but declines occur especially in verbal fluency and executive function/working memory. Numerous predictors and risk factors for cognitive outcomes have been identified (age and pre-operative neuropsychological status appear the most robust) but precise risk estimates cannot yet be confidently offered. Future studies should employ study center consortia, follow uniform reporting criteria (to be developed), capitalize on advances in stimulation, biomarkers, and artificial intelligence, and address DBS in diverse groups. Advances offer an avenue to investigate the amelioration of cognitive deficits in PD using neuromodulation.

Diagnostic criteria for mild cognitive impairment in Parkinson's disease: Movement Disorder Society Task Force guidelines.

Mild cognitive impairment is common in nondemented Parkinson's disease (PD) patients and may be a harbinger of dementia. In view of its importance, the Movement Disorder Society commissioned a task force to delineate diagnostic criteria for mild cognitive impairment in PD. The proposed diagnostic criteria are based on a literature review and expert consensus. This article provides guidelines to characterize the clinical syndrome and methods for its diagnosis. The criteria will require validation, and possibly refinement, as additional research improves our understanding of the epidemiology, presentation, neurobiology, assessment, and long-term course of this clinical syndrome. These diagnostic criteria will support future research efforts to identify at the earliest stage those PD patients at increased risk of progressive cognitive decline and dementia who may benefit from clinical interventions at a predementia stage.

Impact of Mild Cognitive Impairment on Quality of Life in Young and Typical Onset Parkinson's Disease.

INTRODUCTION: Younger age of onset and mild cognitive impairment (MCI) are both independently associated with poorer quality of life (QOL) in Parkinson's disease (PD). OBJECTIVES: The primary objective was to determine whether MCI differentially impacts QOL in young-onset PD (YOPD) and typical-onset PD (TOPD). METHODS: YOPD patients (n = 77) were diagnosed at age 50 or younger, TOPD (n = 77) were diagnosed after age 50, and the groups were matched for cognitive status, education, and disease duration. Patients' cognitive status was classified as MCI or cognitively normal (CN) based on MDS Level II criteria. QOL was assessed using the Parkinson's Disease Questionnaire (PDQ-39). ANCOVAs were conducted for each PDQ-39 subscale, with age of onset and cognitive status as between-subjects factors and several covariates included. RESULTS: An interaction for the Cognition domain revealed that in TOPD, PD-MCI patients reported poorer QOL than CN patients, whereas there was no effect of MCI on cognitive satisfaction in YOPD. There was a main effect of age on Emotional Well-Being, as YOPD reported poorer QOL than TOPD in this domain. There were main effects of cognitive status, with PD-MCI patients reporting worse QOL than CN patients in the domains of Social Support, Communication, ADLs, and Mobility. CONCLUSIONS: The interaction revealed that PD-MCI has a greater impact on degree of cognitive concerns ("cognitive QOL") in TOPD versus YOPD. A more nuanced understanding of the effects of age of onset, MCI, and their interactions on QOL in PD will inform interventions aimed at improving quality of life in this population.

Level I PD-MCI Using Global Cognitive Tests and the Risk for Parkinson's Disease Dementia.

Background: The 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. Methods: The 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. Results: PD-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. Conclusion: MMSE and MoCA predict conversion to PDD. However, Level II neuropsychological assessment seems the preferred assessment for PD-MCI.

MDS Task Force on mild cognitive impairment in Parkinson's disease: critical review of PD-MCI.

There is controversy regarding the definition and characteristics of mild cognitive impairment in Parkinson's disease. The Movement Disorder Society commissioned a Task Force to critically evaluate the literature and determine the frequency and characteristics of Parkinson's disease-mild cognitive impairment and its association with dementia. A comprehensive PubMed literature review was conducted using systematic inclusion and exclusion criteria. A mean of 26.7% (range, 18.9%-38.2%) of nondemented patients with Parkinson's disease have mild cognitive impairment. The frequency of Parkinson's disease-mild cognitive impairment increases with age, disease duration, and disease severity. Impairments occur in a range of cognitive domains, but single domain impairment is more common than multiple domain impairment, and within single domain impairment, nonamnestic is more common than amnestic impairment. A high proportion of patients with Parkinson's disease-mild cognitive impairment progress to dementia in a relatively short period of time. The primary conclusions of the Task Force are that: (1) Parkinson's disease-mild cognitive impairment is common, (2) there is significant heterogeneity within Parkinson's disease-mild cognitive impairment in the number and types of cognitive domain impairments, (3) Parkinson's disease-mild cognitive impairment appears to place patients at risk of progressing to dementia, and (4) formal diagnostic criteria for Parkinson's disease-mild cognitive impairment are needed.