Cut-off score of the Mattis Dementia Rating Scale for screening dementia in Parkinson's disease

Glucagon-like peptide-1 class drugs show clear protective effects in Parkinson's and Alzheimer's disease clinical trials: A revolution in the making?

Parkinson's disease (PD) is a complex syndrome for which there is no disease-modifying treatment on the market. However, a group of drugs from the Glucagon-like peptide-1 (GLP-1) class have shown impressive improvements in clinical phase II trials. Exendin-4 (Bydureon), Liraglutide (Victoza, Saxenda) and Lixisenatide (Adlyxin), drugs that are on the market as treatments for diabetes, have shown clear effects in improving motor activity in patients with PD in phase II clinical trials. In addition, Liraglutide has shown improvement in cognition and brain shrinkage in a phase II trial in patients with Alzheimer disease (AD). Two phase III trials testing the GLP-1 drug semaglutide (Wegovy, Ozempic, Rybelsus) are ongoing. This perspective article will summarize the clinical results obtained so far in this novel research area. We are at a crossroads where GLP-1 class drugs are emerging as a new treatment strategy for PD and for AD. Newer drugs that have been designed to enter the brain easier are being developed already show improved effects in preclinical studies compared with the older GLP-1 class drugs that had been developed to treat diabetes. The future looks bright for new treatments for AD and PD.

Efficacy of non-computerized cognitive rehabilitation in Parkinson's disease: A one year follow up study

In this study, we explored the effect of non-computerized cognitive rehabilitation in patients with Parkinson's disease in comparison with an intervention with elements of music therapy after the completion of a three-month program and one year after the end of the intervention. After the initial neuropsychological examination, the respondents were divided into two intervention groups. The experimental group (n = 26) underwent a twelve-week program of cognitive rehabilitation at a frequency of 60 minutes once a week. The control group (n = 27) underwent an intervention program with elements of music therapy at the same frequency. Respondents who underwent the cognitive rehabilitation program improved in the delayed recall from visual memory in the follow-up examination after the end of the cognitive intervention. One year after the end, the effect of cognitive rehabilitation persisted in delayed recall from visual memory and in executive mental flexibility. Cognitive rehabilitation is an effective approach to compensate for cognitive deficits in P D, but other approaches to cognitive stimulation may be equally effective.

Fundamentals of deep brain stimulation for Parkinson's disease in clinical practice: part 1

Deep brain stimulation (DBS) is recognized as an established therapy for Parkinson's disease (PD) and other movement disorders in the light of the developments seen over the past three decades. Long-term efficacy is established for PD with documented improvement in the cardinal motor symptoms of PD and levodopa-induced complications, such as motor fluctuations and dyskinesias. Timing of patient selection is crucial to obtain optimal benefits from DBS therapy, before PD complications become irreversible. The objective of this first part review is to examine the fundamental concepts of DBS for PD in clinical practice, discussing the historical aspects, patient selection, potential effects of DBS on motor and non-motor symptoms, and the practical management of patients after surgery.

The relationship between objective and subjective executive function in Parkinson's disease

INTRODUCTION

Difficulties in executive functioning (EF) are common in PD; however, the relationship between subjective and objective EF is unclear. Understanding this relationship could help guide clinical EF assessment. This study examined the relationship between subjective self-reported EF (SEF) and objective EF (OEF) and predictors of SEF-OEF discrepancies in PD.

METHOD

One-hundred and sixteen non-demented PD participants completed measures of OEF (i.e. problem-solving, cognitive flexibility, inhibition, and working memory) and SEF (Frontal Systems Behavior Scale-Self Executive Dysfunction Subscale). Pearson bivariate correlations and linear regressions were performed to examine the relationship between SEF and OEF and the non-motor symptoms (e.g. mood, fatigue), demographic, and PD characteristic (e.g. MCI status) predictors of discrepancies between OEF and SEF (|OEF minus SEF scores|). Correlates of under-, over-, and accurate-reporting were also explored.

RESULTS

Greater SEF complaints and worse OEF were significantly associated (β =.200, p = .009) and 64% of participants accurately identified their level of OEF abilities. Fewer years of education and greater symptoms of depression, anxiety, and fatigue significantly correlated with greater discrepancies between OEF and SEF. Fatigue was the best predictor of EF discrepancy in the overall sample (β = .281, p = .022). Exploratory analyses revealed apathy and fatigue associated with greater under-reporting, while anxiety associated with greater over-reporting.

CONCLUSIONS

SEF and OEF are significantly related in PD. Approximately 64% of non-demented persons with PD accurately reported their EF skill level, while 28% under-reported and 8% over-reported. SEF-OEF discrepancies were predicted by fatigue in the overall sample. Preliminary evidence suggests reduced apathy and fatigue symptoms relate to more under-reporting, while anxiety relates to greater over-reporting. Given the prevalence of these non-motor symptoms in PD, it is important to carefully consider them when assessing EF in PD.

Original research: longitudinal evaluation of cognitively demanding daily function using performance-based functional assessment highlights heterogeneous trajectories in cognitive and functional abilities in people with Parkinson's disease

Background

Longitudinal assessment of functional abilities in Parkinson's disease (PD) is needed to determine the efficacy of cognitive interventions in providing meaningful improvements in daily life. Additionally, subtle changes in instrumental activities of daily living may precede a clinical diagnosis of dementia and could aid earlier detection of and intervention for cognitive decline.

Objective

The primary goal was to validate the longitudinal application of the University of California San Diego Performance-Based Skills Assessment (UPSA). An exploratory secondary goal was to determine whether UPSA may identify individuals at higher risk of cognitive decline in PD.

Methods

Seventy participants with PD completed the UPSA with at least one follow-up visit. Linear mixed effects modeling was used to identify associations between baseline UPSA score and cognitive composite score (CCS) over time. Descriptive analysis of four heterogeneous cognitive and functional trajectory groups and individual case examples was performed.

Results

Baseline UPSA score predicted CCS at each timepoint for functionally impaired and unimpaired groups (p < 0.01) but did not predict the rate change in CCS over time (p = 0.83). Participants displayed heterogenous trajectories in both UPSA and CCS during the follow-up period. Most participants maintained both cognitive and functional performance (n = 54), though some displayed cognitive and functional decline (n = 4), cognitive decline with functional maintenance (n = 4), and functional decline with cognitive maintenance (n = 8).

Conclusion

The UPSA is a valid measure of cognitive functional abilities over time in PD. Given the heterogeneity of functional and cognitive trajectories, this performance-based assessment did not predict cognitive decline with this relatively short follow-up. Further work is needed to understand longitudinal functional assessments in PD-associated cognitive impairment.

Patients with Cognitive Impairment in Parkinson's Disease Benefit from Deep Brain Stimulation: A Case-Control Study

Background

Deep brain stimulation (DBS) for Parkinson's disease (PD) is generally contraindicated in persons with dementia but it is frequently performed in people with mild cognitive impairment or normal cognition, and current clinical guidelines are primarily based on these cohorts.

Objectives

To determine if moderately cognitive impaired individuals including those with mild dementia could meaningfully benefit from DBS in terms of motor and non-motor outcomes.

Methods

In this retrospective case-control study, we identified a cohort of 40 patients with PD who exhibited moderate (two or more standard deviations below normative scores) cognitive impairment (CI) during presurgical workup and compared their 1-year clinical outcomes to a cohort of 40 matched patients with normal cognition (NC). The surgery targeted subthalamus, pallidus or motor thalamus, in a unilateral, bilateral or staged approach.

Results

At preoperative baseline, the CI cohort had higher Unified Parkinson's Disease Rating Scale (UPDRS) subscores, but similar levodopa responsiveness compared to the NC cohort. The NC and CI cohorts demonstrated comparable degrees of postoperative improvement in the OFF-medication motor scores, motor fluctuations, and medication reduction. There was no difference in adverse event rates between the two cohorts. Outcomes in the CI cohort did not depend on the target, surgical staging, or impaired cognitive domain.

Conclusions

Moderately cognitively impaired patients with PD can experience meaningful motor benefit and medication reduction with DBS.

Cognitive evaluation in Parkinson's disease: applying the Movement Disorder Society recommendations in a population with a low level of formal education

BACKGROUND

 The diagnosis of cognitive disorders in Parkinson disease (PD) can be very challenging. Aiming at establishing uniform and reliable diagnostic procedures, the International Parkinson's Disease and Movement Disorder Society (MDS) commissioned task forces to delineate diagnostic criteria for mild cognitive impairment (MCI) and dementia in PD.

OBJECTIVES

 To investigate the applicability of the MDS recommendations for cognitive evaluation in a Brazilian sample of patients with PD with low levels of formal education.

METHODS

 A total of 41 patients with PD were subjected to a comprehensive neuropsychological evaluation based on tests proposed by the MDS, which included the Mini-Mental State Examination, the Mattis Dementia Rating Scale (MDRS), the Trail Making Test (TMT) parts A and B, in addition to language and memory skills assessment. Neuropsychiatric and daily functioning features were also evaluated. Spearman correlation analyses were used to evaluate the association between the scores obtained in the cognitive scales and demographic/clinical variables.

RESULTS

 Although none of the participants had a formal diagnosis of dementia, 50% presented some degree of cognitive impairment when considering the results of the MDRS. Of note, a noticeable number of patients was not able to complete the full neuropsychological assessment. The TMT part B was the most difficult task, being completed by only 22 participants (54%). As expected, the greater the educational level, the better the performance on the cognitive tests. Better motor function was also associated with better scores in cognition.

CONCLUSIONS

 Adopting strict inclusion/exclusion criteria and a comprehensive clinical evaluation, we found remarkable limitations for the MDS recommendations when individuals with low educational levels are considered. A revision of the current guidelines is necessary considering differences among populations, especially related to formal education.

Annonaceae Consumption Worsens Disease Severity and Cognitive Deficits in Degenerative Parkinsonism

BACKGROUND

High consumption of Annona muricata fruit has been previously identified as a risk factor for atypical parkinsonism in the French Caribbean islands.

OBJECTIVE

We tested whether consumption of Annonaceae products could worsen the clinical phenotype of patients with any form of degenerative parkinsonism.

METHODS

We analyzed neurological data from 180 Caribbean parkinsonian patients and specifically looked for dose effects of lifelong, cumulative Annonaceae consumption on cognitive performance. Using unsupervised clustering, we identified one cluster with mild/moderate symptoms (N = 102) and one with severe symptoms including cognitive impairment (N = 78).

RESULTS

We showed that even low cumulative consumption of fruits/juices (>0.2 fruit-years) or any consumption of herbal tea from Annonaceae worsen disease severity and cognitive deficits in degenerative parkinsonism including Parkinson's disease (OR fruits-juices: 3.76 [95% CI: 1.13-15.18]; OR herbal tea: 2.91 [95% CI: 1.34-6.56]).

CONCLUSION

We suggest that more restrictive public health preventive recommendations should be made regarding the consumption of Annonaceae products. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Prospective predictors of care partner burden and depression in Parkinson's disease

OBJECTIVES

Care partners who provide informal care to individuals with Parkinson's disease (PD) report higher levels of burden and depression; however, longitudinal research on these symptoms is scarce. The current study assessed changes in care partner burden and depression, and patient and care partner predictors of these symptoms over time. Such knowledge may provide important information for assessment and treatment of depression and burden in care partners of individuals with PD.

RESEARCH DESIGN AND METHODS

Participants were 88 PD patients without dementia and their self-identified care partner (n = 88). Care partners completed the Geriatric Depression Scale and Zarit Burden Interview. PD participants completed mood questionnaires and a motor exam at baseline and 2 year follow-up. Relationships among care partner burden and depression over time with patient and care partner predictors (i.e., demographic, mood, and disease characteristics) were assessed using correlations and regression analyses.

RESULTS

Care partner burden and depression significantly increased over an approximate 2 year period. Greater baseline disease severity predicted worsening of care partner burden (p = 0.028), while baseline patient depression predicted worsening of care partner depression (p = 0.002).

CONCLUSIONS

Results highlight differential impacts of specific PD symptoms on worsening care partner burden compared to depression; increased PD disease severity predicts increased burden, while patient mood predicts worsening of depression over time. Targeting PD disease severity and mood symptoms may prevent the progression of care partner burden and depression.

Changes in Self- and Informant-Reported Frontal Behaviors in Parkinson's Disease: A Longitudinal Study

OBJECTIVE

Frontal behaviors (i.e., executive dysfunction, disinhibition, apathy) are common in Parkinson's disease (PD). However, it is unclear if patient and informant reports of patient frontal behaviors are in agreement over time.

METHOD

Sixty-two PD patients without dementia and their informants (87% spouses/partners) completed the self- and informant-versions of the Frontal Systems Behavior Scale at baseline and 2-year follow-up. Dyad ratings were compared and predictors of behavior ratings were examined.

RESULTS

Patient and informant reports at baseline and follow-up were in agreement, with significant increases in overall frontal behaviors, executive dysfunction, and apathy. Higher levels of baseline patient depression and caregiver burden predicted decrements in patient-reported executive function; worse patient cognition at baseline predicted worsening apathy as rated by informants.

CONCLUSIONS

PD patients and their informants are concordant in their ratings of worsening frontal behaviors over time. Targeting patient depression, cognition, and caregiver burden may improve decrements in frontal behaviors (executive dysfunction and apathy) in PD.

Randomized controlled trial of neurologic music therapy in Parkinson's disease: research rehabilitation protocols for mechanistic and clinical investigations

Background

Presently available medications and surgical treatments for Parkinson’s disease have limited effects on fine motor problems and often leave patients with significant fine motor disability. Standard of care occupational therapy (OT) yields low efficacy, potentially due to a lack of standard protocols. Neurologic music therapy (NMT) techniques, especially rhythmic auditory stimulation which relies on interaction between rhythm and movement, have shown to be effective in PD gait rehabilitation possibly through their reliance on neural pathways that are not affected by PD. Therapeutic instrumental music performance (TIMP) is one other NMT technique that holds promise but which mode of action and efficacy has not been investigated in PD yet.

Methods

One hundred PD participants will be randomly assigned to receive 15 sessions of either TIMP with rhythm or TIMP without rhythm, standard of care OT, or to be waitlisted (control) over 5 consecutive weeks. Brain oscillatory responses will be collected using magnetoencephalography during an auditory-motor task to understand the underlying mechanisms. The Grooved Pegboard, the UPDRS III finger tap, and the finger-thumb opposition will be assessed to investigate clinical changes related to fine motor function. This project will also serve to confirm or refute our pilot data findings suggesting NMT relies on compensatory brain networks utilized by the PD brain to bypass the dysfunctional basal ganglia.

Discussion

This study aims to use standardized TIMP and OT research protocols for investigating the neuronal pathways utilized by each intervention and possibly study their efficacy with respect to fine motor rehabilitation via a randomized control trial in the PD population.

Trial registration

ClinicalTrials.gov NCT03049033. Registered on September 29, 2020

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05560-7.

Multiculturalism: A Challenge for Cognitive Screeners in Parkinson's Disease

BACKGROUND

The Montreal Cognitive Assessment (MoCA) and the Dementia Rating Scale-2 (DRS-2) are recommended screeners for Parkinson's disease mild cognitive impairment (PD-MCI). Cross-cultural studies examining their diagnostic precision have not addressed cultural bias in a multicultural setting.

OBJECTIVES

To compare DRS-2 and MoCA performance between patients born in Canada, the USA, and the UK (Anglosphere group) and immigrant patients born elsewhere (International group). To identify sources of cultural bias by comparing group characteristics, and by assessing the relationships between performance and immigration and socio-development variables. To examine the diagnostic precision of both tools in detecting PD-MCI in each group.

METHODS

We conducted a clinical chart review of advanced PD patients who completed cognitive screeners (MoCA: n = 288, 30% International group; DRS-2: n = 426, 31% International group). All completed a comprehensive neuropsychological assessment to apply Level II PD-MCI diagnostic criteria.

RESULTS

The International group performed worse than the Anglosphere group on the MoCA and DRS-2, and the only variable that accounted for some of the group difference was the Historical Index of Human Development, a societal variable, which fully mediated the group effect on the DRS-2. Diagnostic precision of the MoCA was at chance level in the International group, and was poorer than that of the DRS-II in this group and that of the MoCA in the Anglosphere group, although these were considered poor.

CONCLUSIONS

Our results support the recommendation to exert caution in using cognitive screeners to capture PD-MCI in all patients and particularly with first generation immigrants.

Central Pain in Parkinson's Disease: Behavioral and Cognitive Characteristics

Introduction

Pain is a major nonmotor symptom of Parkinson's disease (PD), and central parkinsonian pain is the core feature of the putative Park pain subtype of PD. This study aimed to explore the cognitive and behavioral profile of PD patients with central parkinsonian pain. Material and Methods. A structured interview was used to identify and characterize pain in a cohort of 260 consecutive PD patients. The Ford classification of pain was applied. The Dementia Rating Scale-2 (DRS-2) and the Impulse Control Disorders in Parkinson's Disease Short Form (QUIP-S) were administered, and patients' smoking habits were recorded. The Unified Parkinson's Disease Rating Scale (UPDRS) was used to assess motor and nonmotor symptoms in off and on conditions.

Results

One hundred and eighty-eight patients (68%) reported pain; and in 41 (22%) of them, the pain was classified as central parkinsonian pain. PD patients with central parkinsonian pain had better cognitive performance in DRS-2 Initiation/Perseveration and Conceptualization subscales but reported more other compulsive behaviors (e.g., hobbyism, punding, and walkabout) and had more current smoking habits than those without pain or with non-central parkinsonian pain. Multiple logistic regression analyses revealed that the DRS-2 Conceptualization subscale, other compulsive behaviors, and smoking habits remained statistically associated with central parkinsonian pain even when other significant covariates were considered. Only patients with pain, regardless of type, had a gambling disorder. Discussion. The study results provide further evidence that pain revealed that patients with central parkinsonian pain are more likely to present compulsive or addictive behaviors, despite having more preserved cognitive performance. Patients with central parkinsonian pain appear to have a distinct phenotype of PD.

REM Sleep Behavior Disorder in Parkinson's Disease: Change in Cognitive, Psychiatric, and Functional Outcomes from Baseline to 16-47-Month Follow-Up

OBJECTIVE

Rapid Eye Movement Sleep Behavior Disorder (RBD) is common in Parkinson's Disease (PD) and is associated with cognitive impairment; however, the majority of the evidence on the impact of RBD on multidomain cognitive batteries in PD is cross-sectional. This study evaluated the longitudinal impact of probable RBD (pRBD) on cognitive, psychiatric, and functional outcomes in people with PD.

METHOD

Case-control study. A total of 65 people with PD completed the study protocol at baseline and 16-to-47-month follow-up. Participants were classified as pRBD+ (n = 25) or pRBD- (n = 40) based on an established cutoff of 6 on the RBD Sleep Questionnaire (RBDSQ). Participants also completed a) comprehensive cognitive testing, b) self-report measures of depression, anxiety, and apathy, and c) performance-based and other-report forms of instrumental activities of daily living.

RESULTS

Baseline mean age was 67.8 (SD = 8.1; range = 45-86) and baseline mean years of education was 16.4 (SD = 2.1; range = 12-20). The two groups did not differ on measured demographic characteristics. Baseline mean T-scores for cognitive tests were in the average range (46-55). Hierarchical linear models tested group differences in cognitive and functional decline from baseline to follow-up, controlling for appropriate demographic and psychiatric variables. Compared to the pRBD- group, pRBD+ participants showed greater decline in attention/working memory (r = -0.31; p = 0.01) and UPSA financial skills (r = -0.31; p = 0.01). No other group differences approached significance.

CONCLUSIONS

RBD may differentially affect attention/working memory and financial abilities in PD. Results underscore the importance of regular RBD screening in older adults with PD in order to triage symptomatic patients to appropriate cognitive and medical interventions.

Informant-Reported Cognitive Decline is Associated with Objective Cognitive Performance in Parkinson's Disease

OBJECTIVE

The utility of informant-based measures of cognitive decline to accurately describe objective cognitive performance in Parkinson's disease (PD) without dementia is uncertain. Due to the clinical relevance of this information, the purpose of this study was to examine the relationship between informant-based reports of patient cognitive decline via the Informant Questionnaire of Cognitive Decline in the Elderly (IQCODE) and objective cognition in non-demented PD controlling for cognitive status (i.e., mild cognitive impairment; PD-MCI and normal cognition; PD-NC).

METHOD

One-hundred and thirty-nine non-demented PD participants (PD-MCI n = 38; PD-NC n = 101) were administered measures of language, executive function, attention, learning, delayed recall, visuospatial function, mood, and motor function. Each participant identified an informant to complete the IQCODE and a mood questionnaire.

RESULTS

Greater levels of informant-based responses of patient cognitive decline on the IQCODE were significantly associated with worse objective performance on measures of global cognition, attention, learning, delayed recall, and executive function in the overall sample, above and beyond covariates and cognitive status. However, the IQCODE was not significantly associated with language or visuospatial function.

CONCLUSIONS

Results indicate that informant responses, as measured by the IQCODE, may provide adequate information on a wide range of cognitive abilities in non-demented PD, including those with MCI and normal cognition. Findings have important clinical implications for the utility of the IQCODE in the identification of PD patients in need of further evaluation, monitoring, and treatment.

Altered Inhibitory Mechanisms in Parkinson's Disease: Evidence From Lexical Decision and Simple Reaction Time Tasks

INTRODUCTION

Although the motor signs of Parkinson's disease (PD) are well defined, nonmotor symptoms, including higher-level language deficits, have also been shown to be frequent in patients with PD. In the present study, we used a lexical decision task (LDT) to find out whether access to the mental lexicon is impaired in patients with PD, and whether task performance is affected by bradykinesia.

MATERIALS AND METHODS

Participants were 34 nondemented patients with PD, either without (off) medication (n = 16) or under optimum (on) medication (n = 18). A total of 19 age-matched control volunteers were also recruited. We recorded reaction times (RTs) to the LDT and a simple RT (control) task. In each task, stimuli were either visual or auditory. Statistical analyses consisted of repeated-measures analyses of variance and Tukey's HSD post hoc tests.

RESULTS

In the LDT, participants with PD both off and on medication exhibited intact access to the mental lexicon in both modalities. In the visual modality, patients off medication were just as fast as controls when identifying real words, but slower when identifying pseudowords. In the visual modality of the control task, RTs for pseudowords were significantly longer for PD patients off medication than for controls, revealing an unexpected but significant lexicality effect in patients that was not observed in the auditory modality. Performances of patients on medication did not differ from those of age-matched controls.

DISCUSSION

Motor execution was not slowed in patients with PD either off or on medication, in comparison with controls. Regarding lexical access, patients off medication seemed to (1) have difficulty inhibiting a cognitive-linguistic process (i.e., reading) when it was not required (simple reaction time task), and (2) exhibit a specific pseudoword processing deficit in the LDT, which may have been related to impaired lateral word inhibition within the mental lexicon. These deficits seemed to be compensated by medication.

Antisaccade, a predictive marker for freezing of gait in Parkinson's disease and gait/gaze network connectivity

Freezing of gait is a challenging sign of Parkinson's disease associated with disease severity and progression and involving the mesencephalic locomotor region. No predictive factor of freezing has been reported so far. The primary objective of this study was to identify predictors of freezing occurrence at 5 years. In addition, we tested whether functional connectivity of the mesencephalic locomotor region could explain the oculomotor factors at baseline that were predictive of freezing onset. We performed a prospective study investigating markers (parkinsonian signs, cognitive status and oculomotor recordings, with a particular focus on the antisaccade latencies) of disease progression at baseline and at 5 years. We identified two groups of patients defined by the onset of freezing at 5 years of follow-up; the 'Freezer' group was defined by the onset of freezing in the ON medication condition during follow-up (n = 17), while the 'non-Freezer' group did not (n = 8). Whole brain resting-state functional MRI was recorded at baseline to determine how antisaccade latencies were associated with connectivity of the mesencephalic locomotor region networks in patients compared to 25 age-matched healthy volunteers. Results showed that, at baseline and compared to the non-Freezer group, the Freezer group had equivalent motor or cognitive signs, but increased antisaccade latencies (P = 0.008). The 5-year course of freezing of gait was correlated with worsening antisaccade latencies (P = 0.0007). Baseline antisaccade latencies was also predictive of the freezing onset (χ2 = 0.008). Resting state connectivity of mesencephalic locomotor region networks correlated with (i) antisaccade latency differently in patients and healthy volunteers at baseline; and (ii) the further increase of antisaccade latency at 5 years. We concluded that antisaccade latency is a predictive marker of the 5-year onset of freezing of gait. Our study suggests that functional networks associated with gait and gaze control are concurrently altered during the course of the disease.

EEG-Derived Functional Connectivity Patterns Associated with Mild Cognitive Impairment in Parkinson's Disease

OBJECTIVE

To evaluate EEG-derived functional connectivity (FC) patterns associated with mild cognitive impairment (MCI) in Parkinson's disease (PD).

METHODS

A sample of 15 patients without cognitive impairment (PD-WCI), 15 with MCI (PD-MCI), and 26 healthy subjects were studied. The EEG was performed in the waking functional state with eyes closed, for the functional analysis it was used the synchronization likelihood (SL) and graph theory (GT).

RESULTS

PD-MCI patients showed decreased FC in frequencies alpha, in posterior regions, and delta with a generalized distribution. Patients, compared to the healthy people, presented a decrease in segregation (lower clustering coefficient in alpha p = 0.003 in PD-MCI patients) and increased integration (shorter mean path length in delta (p = 0.004) and theta (p = 0.002) in PD-MCI patients). There were no significant differences in the network topology between the parkinsonian groups. In PD-MCI patients, executive dysfunction correlated positively with global connectivity in beta (r = 0.47) and negatively with the mean path length at beta (r = -0.45); alterations in working memory were negatively correlated with the mean path length at beta r = -0.45.

CONCLUSIONS

PD patients present alterations in the FC in all frequencies, those with MCI show less connectivity in the alpha and delta frequencies. The neural networks of the patients show a random topology, with a similar organization between patients with and without MCI. In PD-MCI patients, alterations in executive function and working memory are related to beta integration.

Predicting the Severity of Parkinson's Disease Dementia by Assessing the Neuropsychiatric Symptoms with an SVM Regression Model

In this study, we measured the convergence rate using the mean-squared error (MSE) of the standardized neuropsychological test to determine the severity of Parkinson's disease dementia (PDD), which is based on support vector machine (SVM) regression (SVR) and present baseline data in order to develop a model to predict the severity of PDD. We analyzed 328 individuals with PDD who were 60 years or older. To identify the SVR with the best prediction power, we compared the classification performance (convergence rate) of eight SVR models (Eps-SVR and Nu-SVR with four kernel functions (a radial basis function (RBF), linear algorithm, polynomial algorithm, and sigmoid)). Among the eight models, the MSE of Nu-SVR-RBF was the lowest (0.078), with the highest convergence rate, whereas the MSE of Eps-SVR-sigmoid was 0.110, with the lowest convergence rate. The results of this study imply that this approach could be useful for measuring the severity of dementia by comprehensively examining axial atypical features, the Korean instrumental activities of daily living (K-IADL), changes in rapid eye movement sleep behavior disorder (RBD), etc. for optimal intervention and caring of the elderly living alone or patients with PDD residing in medically vulnerable areas.

Delineation of Apathy Subgroups in Parkinson's Disease: Differences in Clinical Presentation, Functional Ability, Health-related Quality of Life, and Caregiver Burden

BACKGROUND

Apathy is a prevalent, multidimensional neuropsychiatric condition in Parkinson's disease (PD). Several authors have proposed apathy subtypes in PD, but no study has examined the classification of PD patients into distinct apathy subtypes, nor has any study examined the clinical utility of doing so.

OBJECTIVES

The current study used a data-driven approach to explore the existence and associated clinical characteristics of apathy subtypes in PD.

METHOD

The Apathy Scale (AS) was administered to 157 non-demented individuals with PD. Participants were classified into apathy subgroups through cluster analysis. Differences among apathy subtypes on external clinical indicators were explored across apathy subgroups.

RESULTS

Individuals with PD were classified into three subgroups: a Non-Apathetic group with low levels of apathy symptoms, a Low Interest/Energy group, characterized by elevated symptoms of low interest/energy and minimal low initiation/emotional indifference symptoms, and a Low Initiation group, characterized by an absence of low interest/energy symptoms and elevated levels of low initiation/emotional indifference symptoms. Both Low Interest/Energy and Low Initiation groups exhibited worse depression, fatigue, anxiety, health-related quality of life, and caregiver burden than the Non-Apathetic subgroup. The Low Initiation group exhibited worse overall cognition, emotional well-being, state anxiety, communicative ability, and functional ability than the Low Interest/Energy group. Importantly, disease-related characteristics did not differ across apathy symptom subgroups.

CONCLUSIONS

Non-demented PD patients can be separated into distinct apathy symptom subgroups, which are differentially associated with important clinical variables. Apathy subgroup membership may reflect disruption to different neural systems independent of disease progression.

REM Sleep Behavior Disorder in Parkinson's Disease: Effects on Cognitive, Psychiatric, and Functional outcomes

OBJECTIVE

Rapid eye movement sleep behavior disorder (RBD) affects 33-46% of patients with Parkinson's disease (PD) and may be a risk factor for neuropsychological and functional deficits. However, the role of RBD on neuropsychological functioning in PD has yet to be fully determined. We, therefore, examined differences in neurocognitive performance, functional capacity, and psychiatric symptoms among nondemented PD patients with probable RBD (PD/pRBD+) and without (PD/pRBD-), and healthy comparison participants (HC).

METHODS

Totally, 172 participants (58 PD/pRBD+; 65 PD/pRBD-; 49 HC) completed an RBD sleep questionnaire, psychiatric/clinical questionnaires, performance-based and self-reported functional capacity measures, and underwent a comprehensive neuropsychological battery assessing attention/working memory, language, visuospatial function, verbal and visual learning and memory, and executive function.

RESULTS

Controlling for psychiatric symptom severity, the PD/pRBD+ group had poorer executive functioning and learning performance than the PD/pRBD- group and poorer neuropsychological functioning across all individual cognitive domains than the HCs. In contrast, PD/pRBD- patients had significantly lower scores than HCs only in the language domain. Moreover, PD/pRBD+ patients demonstrated significantly poorer medication management skills compared to HCs. Both PD groups reported greater depressive and anxiety severity compared to HCs; PD/pRBD+ group also endorsed greater severity of apathy compared to HCs.

CONCLUSIONS

The presence of pRBD is associated with poorer neuropsychological functioning in PD such that PD patients with pRBD have poorer cognitive, functional, and emotional outcomes compared to HC participants and/or PD patients without pRBD. Our findings underscore the importance of RBD assessment for improved detection and treatment of neuropsychological deficits (e.g., targeted cognitive interventions).

Does pallidal neuromodulation influence cognitive decline in Huntington's disease?

OBJECTIVE

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder associated with motor, psychiatric and cognitive deterioration over time. To date, Continuous Electrical Neuromodulation (CEN) of the globus pallidus internus (GPi) has been reported to improve chorea but little is known about cognitive progression in these patients. We propose to examine CEN impact on expected cognitive decline throughout long-term neuropsychological assessment of a cohort of HD patients.

METHOD

13 consecutive HD patients underwent GPi neuromodulation between January 2008 and February 2019. Over a 5-year follow-up period, they received systematic pre- and post-operative assessment according to the existing protocol in our unit. The main outcome measure was the total score obtained on the Mattis Dementia Rating Scale (MDRS) as an indicator of global cognitive function.

RESULTS

Chorea decreased in all patients postoperatively with a mean improvement of 56% despite disease progression over time, according to previous studies. Moreover we found that the global cognitive profile of HD patients treated with CEN was stable during the first 3 years of treatment.

CONCLUSION

We report an unexpected positive influence of GPi continuous electrical neuromodulation on the progression of global cognitive functioning in operated HD patients. This is the most important group of patients treated with this method to our knowledge whatever the sample size remains small. This result provides promising evidence of GPi-CEN efficacy not only in reducing chorea, but also in delaying cognitive decline in HD patients operated at an early stage of the disease.

In-Home Rehabilitation Using a Smartphone App Coupled With 3D Printed Functional Objects: Single-Subject Design Study

BACKGROUND

Stroke is a major cause of long-term disability. While there is potential for improvements long after stroke onset, there is little to support functional recovery across the lifespan. mHealth solutions can help fill this gap. mRehab was designed to guide individuals with stroke through a home program and provide performance feedback.

OBJECTIVE

To examine if individuals with chronic stroke can use mRehab at home to improve upper limb mobility. The secondary objective was to examine if changes in limb mobility transferred to standardized clinical assessments.

METHODS

mRehab consists of a smartphone coupled with 3D printed household items: mug, bowl, key, and doorknob. The smartphone custom app guides task-oriented activities and measures both time to complete an activity and quality of movement (smoothness/accuracy). It also provides performance-based feedback to aid the user in self-monitoring their performance. Task-oriented activities were categorized as (1) object transportation, (2) prehensile grip with supination/pronation, (3) fractionated finger movement, and (4) walking with object. A total of 18 individuals with stroke enrolled in the single-subject experimental design study consisting of pretesting, a 6-week mRehab home program, and posttesting. Pre- and posttesting included both in-laboratory clinical assessments and in-home mRehab recorded samples of task performance. During the home program, mRehab recorded performance data. A System Usability Scale assessed user's perception of mRehab.

RESULTS

A total of 16 participants completed the study and their data are presented in the results. The average days of exercise for each mRehab activity ranged from 15.93 to 21.19 days. This level of adherence was sufficient for improvements in time (t15=2.555, P=.02) and smoothness (t15=3.483, P=.003) in object transportation. Clinical assessments indicated improvements in functional performance (t15=2.675, P=.02) and hand dexterity (t15=2.629, P=.02). Participant's perception of mRehab was positive.

CONCLUSIONS

Despite heterogeneity in participants' use of mRehab, there were improvements in upper limb mobility. Smartphone-based portable technology can support home rehabilitation programs in chronic conditions such as stroke. The ability to record performance data from home rehabilitation offers new insights into the impact of home programs on outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04363944; https://clinicaltrials.gov/ct2/show/NCT04363944.

Prediction of cognitive progression in Parkinson's disease using three cognitive screening measures

Introduction

Cognitive impairment is a common complication of Parkinson's disease (PD) and identifying risk factors for progression to Parkinson's disease dementia (PDD) is important. However, little research has been done comparing the utility of commonly used cognitive screening tests in predicting cognitive progression in PD.

Methods

We retrospectively reviewed data from patients with PD enrolled in the Pacific Udall Center who had baseline and longitudinal neuropsychological and global cognitive screening tests. The diagnostic accuracies of 3 common screening tests were compared: Montreal Cognitive Assessment (MoCA), Mattis Dementia Rating Scale (DRS-2), and Mini Mental Status Examination (MMSE). Cognitive diagnoses of PD with mild cognitive impairment (PD-MCI) and PDD were based on full neuropsychological testing and established Movement Disorder Society criteria. Logistic regression and Cox proportional hazards regression models were used to examine predictors of cognitive decline.

Results

Four hundred seventy patients for whom scores on all 3 screening tests were available from the same assessment were included in a cross-sectional analysis. The MoCA demonstrated the best overall diagnostic accuracy for PD-MCI (AUC = 0.79, sensitivity = 76.4%) and for PDD (AUC = 0.89, sensitivity = 81.0%) compared to the DRS-2 and MMSE.

A longitudinal analysis was performed on the subset of patients (316/470; 67.2%) who were nondemented at baseline and had undergone two or more assessments. After controlling for covariates, the MoCA was the only test associated with progression to PDD (OR = 1.27 95% CI 1.1–1.5, p = 0.001) and faster time to dementia (HR = 1.3, 95% CI 1.1–1.4, p < 0.0001).

Conclusions

This study provides additional support for the use of the MoCA as a primary screening tool for cognitive impairment in PD and is the first to show that the MoCA is a predictor of conversion to PDD.

Functional and Brain Activation Changes Following Specialized Upper-Limb Exercise in Parkinson's Disease

For the management of Parkinson's disease (PD), the concept of forced exercise (FE) has drawn interest. In PD subjects, the FE executed with lower limbs has been shown to lessen symptoms and to promote brain adaptive changes. Our study is aimed to investigate the effect of an upper-limb exercise, conceptually comparable with the FE, in PD. Upper-limb exercise was achieved in a sitting position by using a specially designed device (Angel's Wings^®). Clinical data, computerized dynamic posturography, magnetic resonance imaging (MRI) (resting-state MRI and arterial spin labeling), and neuropsychological tests were used before and after 2 months' exercise training. We found a significant long-lasting improvement in Unified Parkinson Disease Rating Scale (UPDRS)-III and cognitive scales, along with improvement in balance and postural control (better alignment of the gravity center and improvement in weight symmetry and in anticipatory motor strategies). Computerized dynamic posturography pointed out an enhanced central ability to integrate the vestibular signals with afferents from other sensory systems. Neuroimaging analyses after 2 months' exercise training showed, with respect to pretraining condition, many changes. An increase of the cerebral blood flow was evident in the left primary motor cortex (M1), left supplementary motor cortical area, and left cerebellar cortex. The bilateral globus pallidus showed an increased functional connectivity to the right central operculum, right posterior cingulate gyrus, and left sensorimotor cortex. Seed-to-voxel analysis demonstrated a functional connectivity between M1 and the left superior frontal gyrus. Left crus II showed strengthened connections with the left pre-rolandic area, left post-rolandic area, and left supramarginal area. These findings likely reflect compensatory mechanisms to the neuropathological hallmark of PD. Overall, our results show that this upper-limb exercise model, conceptually comparable with the FE already tested in the lower limbs, leads to a global improvement (involving non-exercised limbs) likely consistent with the functional changes observed in the central nervous system.

Characterization of Parkinson's disease using blood-based biomarkers: A multicohort proteomic analysis

BACKGROUND

Parkinson's disease (PD) is a progressive neurodegenerative disease affecting about 5 million people worldwide with no disease-modifying therapies. We sought blood-based biomarkers in order to provide molecular characterization of individuals with PD for diagnostic confirmation and prediction of progression.

METHODS AND FINDINGS

In 141 plasma samples (96 PD, 45 neurologically normal control [NC] individuals; 45.4% female, mean age 70.0 years) from a longitudinally followed Discovery Cohort based at the University of Pennsylvania (UPenn), we measured levels of 1,129 proteins using an aptamer-based platform. We modeled protein plasma concentration (log10 of relative fluorescence units [RFUs]) as the effect of treatment group (PD versus NC), age at plasma collection, sex, and the levodopa equivalent daily dose (LEDD), deriving first-pass candidate protein biomarkers based on p-value for PD versus NC. These candidate proteins were then ranked by Stability Selection. We confirmed findings from our Discovery Cohort in a Replication Cohort of 317 individuals (215 PD, 102 NC; 47.9% female, mean age 66.7 years) from the multisite, longitudinally followed National Institute of Neurological Disorders and Stroke Parkinson's Disease Biomarker Program (PDBP) Cohort. Analytical approach in the Replication Cohort mirrored the approach in the Discovery Cohort: each protein plasma concentration (log10 of RFU) was modeled as the effect of group (PD versus NC), age at plasma collection, sex, clinical site, and batch. Of the top 10 proteins from the Discovery Cohort ranked by Stability Selection, four associations were replicated in the Replication Cohort. These blood-based biomarkers were bone sialoprotein (BSP, Discovery false discovery rate [FDR]-corrected p = 2.82 × 10-2, Replication FDR-corrected p = 1.03 × 10-4), osteomodulin (OMD, Discovery FDR-corrected p = 2.14 × 10-2, Replication FDR-corrected p = 9.14 × 10-5), aminoacylase-1 (ACY1, Discovery FDR-corrected p = 1.86 × 10-3, Replication FDR-corrected p = 2.18 × 10-2), and growth hormone receptor (GHR, Discovery FDR-corrected p = 3.49 × 10-4, Replication FDR-corrected p = 2.97 × 10-3). Measures of these proteins were not significantly affected by differences in sample handling, and they did not change comparing plasma samples from 10 PD participants sampled both on versus off dopaminergic medication. Plasma measures of OMD, ACY1, and GHR differed in PD versus NC but did not differ between individuals with amyotrophic lateral sclerosis (ALS, n = 59) versus NC. In the Discovery Cohort, individuals with baseline levels of GHR and ACY1 in the lowest tertile were more likely to progress to mild cognitive impairment (MCI) or dementia in Cox proportional hazards analyses adjusting for age, sex, and disease duration (hazard ratio [HR] 2.27 [95% CI 1.04-5.0, p = 0.04] for GHR, and HR 3.0 [95% CI 1.24-7.0, p = 0.014] for ACY1). GHR's association with cognitive decline was confirmed in the Replication Cohort (HR 3.6 [95% CI 1.20-11.1, p = 0.02]). The main limitations of this study were its reliance on the aptamer-based platform for protein measurement and limited follow-up time available for some cohorts.

CONCLUSIONS

In this study, we found that the blood-based biomarkers BSP, OMD, ACY1, and GHR robustly associated with PD across multiple clinical sites. Our findings suggest that biomarkers based on a peripheral blood sample may be developed for both disease characterization and prediction of future disease progression in PD.

Factor Analysis of the Apathy Scale in Parkinson's Disease

Background

The Apathy Scale (AS), a popular measure of apathy in Parkinson's disease (PD), has been somewhat limited for failing to characterize dimensions of apathy, such as those involving cognitive, behavioral, and emotional apathy symptoms. This study sought to determine whether factors consistent with these apathy dimensions in PD could be identified on the AS, examine the associations between these factors and disease-related characteristics, and compare PD patients and healthy control (HCs) on identified factors.

Methods

Confirmatory (CFA) and exploratory factor analysis (EFA) were conducted on AS scores of 157 nondemented PD patients to identify AS factors. These factors were then correlated with important disease-related characteristics, and PD and HC participants were compared across these factors.

Results

Previously proposed AS models failed to achieve an adequate fit in CFA. A subsequent EFA revealed two factors on the AS reflecting joint cognitive-behavioral aspects of apathy (Motivation-Interest-Energy) and emotional apathy symptoms (Indifference). Both factors were associated with anxiety, depression, health-related quality of life, and independent activities of daily living, with Indifference associated more with the latter. In addition, only the Indifference factor was associated with cognitive functioning. PD patients reported higher levels of symptoms than HCs on both factors, with the group difference slightly larger on the Motivation-Interest-Energy factor.

Conclusion

The AS can be decomposed into two factors reflecting Motivation-Interest-Energy and Indifference symptoms. These factors are differentially associated with clinical variables, including cognition and independent activities of daily living, indicating the importance of evaluating apathy from a multidimensional perspective.

Does the Geriatric Depression Scale measure depression in Parkinson's disease?

The Geriatric Depression Scale (GDS) is recommended for screening depression in individuals with Parkinson's disease (PD). Empirical evidence, however, is limited regarding its validity and factor structure in PD. Thus, the current study sought to evaluate the convergent and divergent validity of the GDS, as well as the structure and validity of the derived factors.

METHOD

Nondemented individuals with PD (n = 158) completed the GDS-30, and items were subjected to a principle component analysis. Geriatric Depression Scale total and factor scores were correlated with depression items from the Movement Disorder Society Unified Parkinson's disease Rating Scale (MDS-UPDRSd) and Hamilton Rating Scale for Depression (HAMDd), as well as with the Apathy Scale (AS), State-Trait Anxiety Inventory (STAI), Modified Fatigue Impact Scale (MFIS), Parkinson's disease Sleep Scale, and a Subjective Cognitive Function composite score.

RESULTS

The GDS total score was strongly correlated with divergent neuropsychiatric measures (AS, r = 0.57; STAI, r = 0.66; MFIS, r = 0.60), while only moderately correlated with convergent measures (MDS-UPDRSd, r = 0.36; HAMDd, r = 0.32; Ps < 0.05). Linear regression analyses revealed standardized measures of anxiety, apathy, and fatigue independently predicted the GDS total score, while depression items (MDS-UPDRSd and HAMDd) failed to reach significance. Three independent factors were identified: Anxiety, Apathy, and Fatigue. These factors were significantly predicted by their respective convergent measures.

CONCLUSIONS

Taken together, our findings suggest that the GDS and its subscales appear to primarily measure anxiety, apathy, and fatigue in PD, or alternatively, these symptom dimensions may be predominant in PD-depression. Future research with clinically diagnosed samples is needed to confirm these initial findings.

Information Content and Efficiency in the Spoken Discourse of Individuals With Parkinson's Disease

PURPOSE

This study compared the information content and information efficiency of spoken language in individuals with Parkinson's disease (PD) to a healthy comparator group.

METHOD

Nineteen participants with PD and 19 healthy older adults completed the prospective, cross-sectional study. In the primary analysis, 2 language samples elicited by standardized protocols were analyzed for group differences using standard discourse informativeness measures including main events (MEs; Wright, Capilouto, Wagovich, Cranfill, & Davis, 2005) analyzed as %MEs and correct information units (CIUs; Nicholas & Brookshire, 1993) analyzed as %CIUs and CIUs/min. In exploratory analyses, the following were examined: (a) associations among conceptual (%MEs) and lexical (%CIUs and CIUs/min) measures and (b) associations among informativeness measures and age, education, disease severity/duration, global cognition, speech intelligibility, and a verb confrontation naming measure.

RESULTS

In the primary analysis, the PD group differed significantly from the control group on conceptual (%MEs) and lexical measures of content (%CIUs) and efficiency (CIUs/min). In exploratory analyses, for the control group %MEs were significantly correlated with CIUs/min. Significant associations among conceptual and lexical measures of informativeness were not found in the PD group. For controls, there were no significant correlations between informativeness measures and any of the demographic or speech/cognitive/language variables. In the PD group, there was a significant and positive association between CIUs/min and Dementia Rating Scale-Second Edition scores (Mattis, 2001). A significant but negative correlation was found between CIUs/min and motor severity scores. However, %MEs and verb naming were significantly and positively correlated.

CONCLUSIONS

Individuals with PD without dementia demonstrated reduced discourse informativeness that reflects disruptions to both conceptual and lexical discourse processes. In exploratory analyses, reduced efficiency of information content was associated with global cognition and motor severity. Clinical and research implications are discussed within a Cognitivist framework of discourse production (Sheratt, 2007).

Brain PET substrate of impulse control disorders in Parkinson's disease: A metabolic connectivity study

Impulse control disorders (ICDs) have received increased attention in Parkinson's disease (PD) because of potentially dramatic consequences. Their physiopathology, however, remains incompletely understood. An overstimulation of the mesocorticolimbic system has been reported, while a larger network has recently been suggested. The aim of this study is to specifically describe the metabolic PET substrate and related connectivity changes in PD patients with ICDs. Eighteen PD patients with ICDs and 18 PD patients without ICDs were evaluated using cerebral 18F-fluorodeoxyglucose positron emission tomography. SPM-T maps comparisons were performed between groups and metabolic connectivity was evaluated by interregional correlation analysis (IRCA; p < .005, uncorrected; k > 130) and by graph theory (p < .05). PD patients with ICDs had relative increased metabolism in the right middle and inferior temporal gyri compared to those without ICDs. The connectivity of this area was increased mostly with the mesocorticolimbic system, positively with the orbitofrontal region, and negatively with both the right parahippocampus and the left caudate (IRCA). Moreover, the betweenness centrality of this area with the mesocorticolimbic system was lost in patients with ICDs (graph analysis). ICDs are associated in PD with the dysfunction of a network exceeding the mesocorticolimbic system, and especially the caudate, the parahippocampus, and the orbitofrontal cortex, remotely including the right middle and inferior temporal gyri. This latest area loses its central place with the mesocorticolimbic system through a connectivity dysregulation.

Non-demented Parkinson's disease patients with apathy show decreased grey matter volume in key executive and reward-related nodes

Apathy is a common but poorly understood neuropsychiatric disturbance in Parkinson's disease (PD). In a recent study using event-related brain potentials we demonstrated impaired reward processing and compromised mesocortico-limbic pathways in PD patients with clinical symptoms of apathy. Here we aimed to further investigate the involvement of reward circuits in apathetic PD patients by assessing potential differences in brain structure. Using structural magnetic resonance imaging (MRI) and voxel-based morphometry (VBM) we quantified grey matter volume (GMV) in a sample of 18 non-demented and non-depressed PD patients with apathy, and 18 matched non-apathetic patients. Both groups were equivalent in terms of sociodemographic characteristics, disease stage, cognitive performance and L-Dopa equivalent daily dose. Apathetic patients showed significant GMV loss in cortical and subcortical brain structures. Various clusters of cortical GMV decrease were found in the parietal, lateral prefrontal cortex, and orbitofrontal cortex (OFC). The second largest cluster of GMV loss was located in the left nucleus accumbens (NAcc), a subcortical structure that is a key node of the human reward circuit. Isolated apathy in our sample is explained by the combined GMV loss in regions involved in executive functions, and cortical and subcortical structures of the mesolimbic reward pathway. The correlations observed between apathy and cognition suggests apathy as a marker of more widespread brain degeneration even in a sample of non-demented PD patients.

Accuracy of Two Cognitive Screening Tools to Detect Mild Cognitive Impairment in Parkinson's Disease

BACKGROUND

Patients with Parkinson's disease (PD) who have mild cognitive impairment (PD-MCI) are at increased risk of developing PD dementia (PDD). Therefore, it is important to identify PD-MCI in a reliable way.

OBJECTIVES

We evaluated the accuracy of the Parkinson's Disease-Cognitive Rating Scale (PD-CRS) and the Mattis Dementia Rating Scale-2 (MDRS-2) for detecting PD-MCI. Data from healthy subjects were used to correct for demographic influences.

METHODS

We compared the accuracy of the two instruments using ROC analysis. The gold standard was level II diagnosis of PD-MCI according to consensus criteria of the International Parkinson and Movement Disorder Society.

RESULTS

Seventy-five healthy subjects and 125 PD patients were included. Education level, age and sex correlated with the PD-CRS, but only age correlated with the MDRS-2. Twenty-seven percent of the patients had PD-MCI. Areas under the curve (AUCs) for raw scores of PD-CRS and MDRS-2 were 0.83 and 0.81, respectively. At the optimal cut-off for the PD-CRS (101/102), sensitivity was 88% and specificity was 64%. For the MDRS-2 (139/140) sensitivity and specificity were 68% and 79%, respectively.AUCs for demographically corrected scores of PD-CRS and for age-corrected scores of MDRS-2 were 0.80 and 0.78, respectively. At the optimal cut-off for the PD-CRS, sensitivity was 79% and specificity was 72%, while for the MDRS-2 these were 77% and 67%, respectively.

CONCLUSIONS

Both cognitive screening tools are suitable for distinguishing PD-MCI patients from cognitively intact PD patients. Demographical correction of scores did not improve sensitivity and specificity.

Parkinson's disease mild cognitive impairment classifications and neurobehavioral symptoms

BACKGROUND

We apply recently recommended Parkinson's disease mild cognitive impairment (PD-MCI) classification criteria from the movement disorders society (MDS) to PD patients and controls and compare diagnoses to that of short global cognitive scales at baseline and over time. We also examine baseline prevalence of neuropsychiatric symptoms across different definitions of MCI.

METHODS

51 PD patients and 50 controls were classified as cognitively normal, MCI, or demented using MDS criteria (1.5 or 2.0 SD below normative values), Clinical Dementia Rating Scale (CDR), and the Dementia Rating Scale (DRS). All subject had parallel assessment with the Neuropsychiatric inventory (NPI).

RESULTS

We confirmed that PD-MCI (a) is frequent, (b) increases the risk of PDD, and (c) affects multiple cognitive domains. We highlight the predictive variability of different criteria, suggesting the need for further refinement and standardization. When a common dementia outcome was used, the Level II MDS optimal testing battery with impairment defined as two SD below norms in 2+ tests performs the best. Neuropsychiatric symptoms were more common in PD across all baseline and longitudinal cognitive classifications.

CONCLUSIONS

Our results advance previous findings on the utility of MDS PD-MCI criteria for PD patients and controls at baseline and over time. Additionally, we emphasize the possible utility of other cognitive scales and neuropsychiatric symptoms.

Neuropsychiatric symptoms in untreated Parkinson's disease

Neuropsychiatric and cognitive symptoms are common in Parkinson's disease (PD) and may precede and exceed motor symptoms as major factors impacting disease course and quality of life. Neuropsychiatric symptoms (NPS) in PD are various and are attributed to pathologic changes within multiple brain regions, to psychological stress, and to adverse effects of dopamine replacement therapy. Sleep disorders and mood symptoms such as apathy, depression, and anxiety may antedate the development of motor symptoms by years, while other NPS such as impulse control disorders, psychosis, and cognitive impairment are more common in later stages of the disease. Few studies report on NPS in the early, untreated phase of PD. We reviewed the current literature on NPS in PD with a focus on the early, drug-naive stages of PD. Among these early disease stages, premotor and early motor phases were separately addressed in our review, highlighting the underlying pathophysiological mechanisms as well as epidemiological characteristics, clinical features, risk factors, and available techniques of clinical assessment.

Clinical Epidemiology, Evaluation, and Management of Dementia in Parkinson Disease

The prevalence of neurodegenerative diseases such as Parkinson disease (PD) will increase substantially, due to the aging of the population and improved treatments leading to better disease-related outcomes. Dementia is the most common nonmotor symptom in PD, and most patients with PD will have cognitive dysfunction and cognitive decline in the course of their disease. The development of cognitive dysfunction in PD greatly limits the ability to participate in activities of daily living and can be a tipping point for nursing home placement or major caregiver stress. Understanding the different causes of dementia and how to reduce the incidence and impact of secondary cognitive dysfunction in PD are necessary skills for primary care physicians and neurologists. In this review, we discuss the clinical epidemiology of dementia in PD with an emphasis on preventable cognitive dysfunction, present tools for outpatient evaluation of cognitive dysfunction, and describe current pharmacological treatments for dementia in PD.

Impaired Switching from Self-Prepared Actions in Mild Parkinson Disease

BACKGROUND

Planned and initiated actions frequently need to be terminated in favor of another action. It is known that many individuals with Parkinson's disease (PD) have more difficulty self-initiating movement (i.e., endogenously evoked movement)than moving in response to environmental stimuli (i.e., exogenously evoked movement). However, it is not known if individuals with PD display this same endogenous-exogenous asymmetry when needing to terminate, disengage, and reprogram movements.

OBJECTIVE

This study used a novel reaction time (RT) paradigm to test whether patients with mild PD have subclinical deficits of endogenous movement initiation and endogenous movement reprogramming.

METHODS

Twelve non-demented individuals with PD on medication and 15 demographically similar healthy control (HC)participants completed an experimental paradigm that examined their RTs (key press) following self-selected valid action preparation (endogenous cues) versus valid exogenously presented cues. The paradigm also assessed participants' ability to rapidly stop their endogenous or exogenous preparation following an invalid cue and execute an alternative action (key press).

RESULTS

Participants with PD produced similar RTs as controls following endogenous and exogenous valid cues, and following invalid exogenous cues. However, following invalid endogenous cues, PD participants were slower than HC participants to stop an endogenous preparation and execute an alternative action.

CONCLUSIONS

Despite having mild disease and being on dopaminergic medication, these individuals with PD displayed deficits in motor disengagement and reprograming of self-selected actions. Future studies should examine how this phenomenon influences every day actions, as well as possible treatments for this deficit.

The Diagnostic Accuracy of Parkinson's Disease Mild Cognitive Impairment Battery Using the Movement Disorder Society Task Force Criteria

Background

The aim of the present study was to provide empirical evidence regarding the classification accuracy of the International Parkinson and Movement Disorder Society (MDS) neuropsychological battery (NB) in the determination of Parkinson's disease mild cognitive impairment (PD-MCI).

Methods

The present cross-sectional study included 106 PD patients subjected to PD-MCI classification at Level I and 120 healthy controls (HCs). All HC and PD subjects were then assessed with MDS-NB at Level II and matched according to age and education using different thresholds (1.5 and 2.0 standard deviations [SDs] below average).

Results

We found that Level I and II resulted in different classifications of PD-MCI status. Detection thresholds of -1.5 SD and -2.0 SDs at Level II had also a significant impact on the discriminative validity of all measures in the MDS neuropsychological battery, based on area under the curve analyses. Overall, semantic fluency showed the highest potential in all comparisons not only between PD-MCI and HC, but also between PD-MCI and PD with no deficit (PD-ND).

Conclusions

Our results show that the battery at Level II is applicable and that some measures, such as semantic fluency, have high discriminative validity in the detection of PD-MCI versus PD-ND and HCs.

Long-term impact on quality of life of subthalamic nucleus stimulation in Parkinson's disease

Long-term impact of bilateral subthalamic nucleus deep brain stimulation (STN-DBS) on health-related quality of life (HRQOL) and associated factors in patients with Parkinson's disease (PD) are not clear. In this prospective study, we included 69 PD patients (64 % men, mean age 61.3 ± 7.4 and disease duration 13.2 ± 5.7 years) undergoing STN-DBS. They were evaluated preoperatively (baseline), 1 and 5 years postoperatively assessing 39-item Parkinson's Disease Questionnaire (PDQ-39), Schwab and England Activities of Daily Living Scale (SEADL), Unified Parkinson's Disease Rating Scale (UPDRS) off- and on-medication, patient diaries, dopaminergic treatment, mortality and surgical complications. Five years postoperatively, off-medication, there were improvements from baseline in UPDRS-II and III total (27.2 and 26.7 %, respectively) and SEADL (18.6 % more completely independent patients) (p < 0.05) scores, while on-medication, there was a deterioration in UPDRS-III (37.8 %, mainly axial signs) (p < 0.05) and minor improvements in SEADL (3.7 %). While at 1 year PDQ-39, the summary index improved substantially (36.5 %) (p < 0.05), at 5 years patients regressed (only 8.8 %) (p < 0.05), though changes in PDQ-39 subscores remained significant, with improvements in ADL (18.8 %), emotional well-being (19.0 %), stigma (36.4 %) and discomfort (20.6 %), despite worsening in communication (47.8 %) (p < 0.05). Lower preoperative PDQ-39 summary index and greater 1-year UPDRS-III-off total score gain predicted better long-term HRQOL. STN-DBS produces long-term improvements in HRQOL in PD. Preoperative HRQOL and short-term postoperative changes in off-medication motor status may predict long-term HRQOL in PD following STN-DBS.

Parkinson's Disease--Cognitive Functional Rating Scale across different conditions and degrees of cognitive impairment

BACKGROUND/AIMS

The Parkinson's Disease--Cognitive Functional Rating Scale (PD-CFRS) was designed to avoid motor biases in capturing the functional impact of cognitive impairment in Parkinson's disease (PD). Its performance capturing functional impairment in other conditions leading to cognitive dysfunction is unknown. We compare it with non-specific Instrumental Activities of Daily Living scales.

METHODS

Two hundred consecutive patients diagnosed in a community hospital with mild cognitive impairment (MCI) [31 MCI-amnestic; 33 MCI-multi-domain; 33 PD-MCI] and dementia [35 Alzheimer's disease; 34 vascular dementia; 34 PD with dementia] were assessed on the PD-CFRS, the Blessed Dementia Scale (BDS), the Clinical Dementia Rating--Sum of Boxes (CDR-SOB), and given a comprehensive cognitive assessment. Diagnostic accuracy and optimal cut-off scores were calculated for the PD-CFRS and compared with each functional measure.

RESULTS

The PD-CFRS presented high concurrent validity and significant correlation with both BDS and CDR-SOB, and cognitive scores offering a similar discrimination accuracy to non-specific scales [PD-CFRS ≥ 9 (sensitivity= 0.94; specificity = 0.95)]. No changes appear in cut-off scores when excluding PD patients. Effect size analysis indicated no relevant interference with PD-CFRS scores between the principal cognitive subgroups.

DISCUSSION

The findings extend the clinimetric properties of the PD-CFRS and indicate it as an adequate instrument to capture the full spectrum of functional consequences of cognitive decline in the community.

Do CSF Biomarkers Predict Progression to Cognitive Impairment in Parkinson's disease patients? A Systematic Review

Many patients with Parkinson's disease (PD) will develop cognitive impairment. Cross-sectional studies have shown that certain protein levels are altered in the cerebrospinal fluid (CSF) of PD patients with dementia and are thought to represent potential biomarkers of underlying pathogenesis. Recent studies suggest that CSF biomarker levels may be predictive of future risk of cognitive decline in non-demented PD patients. However, the strength of this evidence and difference between specific CSF biomarkers is not well delineated. We therefore performed a systematic review to assess if levels of specific CSF protein biomarkers are predictive of progression to cognitive impairment. Nine articles were identified that met inclusion criteria for the review. Findings from the review suggest a convergence of evidence that a low baseline Aβ42 in the CSF of non-demented PD patients predicts development of cognitive impairment over time. Conversely, there is limited evidence that CSF levels of tau, either total tau or phosphorylated tau, is a useful predictive biomarker. There are mixed results for other CSF biomarkers such as α-synuclein, Neurofilament light chain, and Heart fatty acid-binding protein. Overall the results of this review show that certain CSF biomarkers have better predictive ability to identify PD patients who are at risk for developing cognitive impairment. Given the interest in developing disease-modifying therapies, identifying this group will be important for clinical trials as initiation of therapy prior to the onset of cognitive decline is likely to be more efficacious.