Test-retest reliability of the dementia rating scale-2: alternate form

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.

Does Prefrontal Glutamate Index Cognitive Changes in Parkinson's Disease?

Introduction

Cognitive impairment is a highly prevalent non-motor feature of Parkinson's disease (PD). A better understanding of the underlying pathophysiology may help in identifying therapeutic targets to prevent or treat dementia. This study sought to identify metabolic alterations in the prefrontal cortex (PFC), a key region for cognitive functioning that has been implicated in cognitive dysfunction in PD.

Methods

Proton Magnetic Resonance Spectroscopy was used to investigate metabolic changes in the PFC of a cohort of cognitively normal individuals without PD (CTL), as well as PD participants with either normal cognition (PD-NC), mild cognitive impairment (PD-MCI), or dementia (PDD). Ratios to Creatine (Cre) resonance were obtained for glutamate (Glu), glutamine and glutamate combined (Glx), N-acetylaspartate (NAA), myoinositol (mI), and total choline (Cho), and correlated with cognitive scores across multiple domains (executive function, learning and memory, language, attention, visuospatial function, and global cognition) administered to the PD participants only.

Results

When individuals retain cognitive capabilities, the presence of Parkinson's disease does not create metabolic disturbances in the PFC. However, when cognitive symptoms are present, PFC Glu/Cre ratios decrease with significant differences between the PD-NC and PPD groups. In addition, Glu/Cre ratios and memory scores were marginally associated, but not after Bonferroni correction.

Conclusion

These preliminary findings indicate that fluctuations in prefrontal glutamate may constitute a biomarker for the progression of cognitive impairments in PD. We caution for larger MRS investigations of carefully defined PD groups.

Profiling Parkinson's disease cognitive phenotypes via resting-state magnetoencephalography

Aberrant brain oscillations are a hallmark of Parkinson's disease (PD) pathophysiology and may be related to both motor and nonmotor symptoms. Mild cognitive impairment (MCI) affects many people with PD even at the time of diagnosis and conversion risks to PD dementia (PDD) are very high. Unfortunately, pharmacotherapies are not addressing cognitive symptoms in PD. Profiling PD cognitive phenotypes (e.g., MCI, PDD, etc.) may therefore help inform future treatments. Neurophysiological methods, such as magnetoencephalography (MEG), offer the advantage of observing oscillatory patterns, whose regional and temporal profiles may elucidate how cognitive changes relate to neural mechanisms. We conducted a resting-state MEG cross-sectional study of 89 persons with PD stratified into three phenotypic groups: normal cognition, MCI, and PDD, to identify brain regions and frequencies most associated with each cognitive profile. In addition, a neuropsychological battery was administered to assess each domain of cognition. Our data showed higher power in lower frequency bands (delta and theta) observed along with more severe cognitive impairment and associated with memory, language, attention, and global cognition. Of the total 119 brain parcels assessed during source analysis, widespread group differences were found in the beta band, with significant changes mostly occurring between the normal cognition and MCI groups. Moreover, bilateral frontal and left-hemispheric regions were particularly affected in the other frequencies as cognitive decline becomes more pronounced. Our results suggest that MCI and PDD may be qualitatively distinct cognitive phenotypes, and most dramatic changes seem to have happened when the PD brain shows mild cognitive decline.NEW & NOTEWORTHY Can we better stage cognitive decline in patients with Parkinson's disease (PD)? Here, we provide evidence that mild cognitive impairment, rather than being simply a milder form of dementia, may be a qualitatively distinct phase in its development. We suggest that the most dramatic neurophysiological changes may occur during the time the PD brain transitions from normal cognition to MCI, then compensatory changes further occur as the brain "switches" to a dementia state.

A novel approach to understanding Parkinsonian cognitive decline using minimum spanning trees, edge cutting, and magnetoencephalography

Graph theory-based approaches are efficient tools for detecting clustering and group-wise differences in high-dimensional data across a wide range of fields, such as gene expression analysis and neural connectivity. Here, we examine data from a cross-sectional, resting-state magnetoencephalography study of 89 Parkinson’s disease patients, and use minimum-spanning tree (MST) methods to relate severity of Parkinsonian cognitive impairment to neural connectivity changes. In particular, we implement the two-sample multivariate-runs test of Friedman and Rafsky (Ann Stat 7(4):697–717, 1979) and find it to be a powerful paradigm for distinguishing highly significant deviations from the null distribution in high-dimensional data. We also generalize this test for use with greater than two classes, and show its ability to localize significance to particular sub-classes. We observe multiple indications of altered connectivity in Parkinsonian dementia that may be of future use in diagnosis and prediction.

Longitudinal cognitive decline in mild cognitive impairment subjects with early amyloid-β neocortical deposition

PURPOSE

The rate of clinical progression of cognitive impairment in subjects with early amyloid deposition is unknown. The primary aim of the study was to follow the rate of cognitive decline over 1 year in patients with amnestic mild cognitive impairment (aMCI) by determining amyloid retention levels in terms of standardized uptake value ratios (SUVr) that ranged from 0.85 to 1.57. The secondary objective was to compare the rate of cognitive decline between subjects with and without early amyloid positivity.

METHODS

Of 66 aMCI subjects evaluated with [¹⁸F]florbetaben PET imaging and neuropsychological tests at baseline, 41 completed the 1-year follow-up. Amyloid status was determined with SUVr cut-off values generated from baseline images by visual assessment by three independent certified readers. Repeated-measures ANOVA with amyloid load and neuropsychological scores as the main effects was use to test group, time and group-by-time interactions. The Tukey post-hoc test was used to analyse all significant interactions.

RESULTS

Of the 41 aMCI subjects, 38 completed the assessment according to the study protocol. Amyloid-positive (Aβ+ ) subjects (N = 18, age 75.6 ± 5.8 years, six men, 12 women) showed greater clinical deterioration according to the Mattis Dementia Rating Scale (MDRS) score (p = 0.006). Amyloid-negative (Aβ-) subjects (N = 20, age 72.4 ± 5.8 years, 11 men, 6 women) showed no significant changes in MDRS score over 1 year. MDRS score significantly decreased (MDRS+) in 37% of the aMCI subjects, and remained stable (MDRS-) in the remaining 63%. Among subjects with cognitive deterioration, 86% were Aβ+ and 14% were Aβ-, while 25% of the MDRS- subjects were Aβ+ and 75% were Aβ- (χ² = 13, P = 0.0003). SUVr above 1.21 identified individuals who would show significant progression over 1 year, with a sensitivity of 67% and a specificity of 90%, as compared to Aβ- subjects. The positive predictive value, negative predictive value, and likelihood ratio were 86% (95% CI 70-94%), 75% (95% CI 58-87%), 7 (95% CI 5-10).

CONCLUSION

This study demonstrated that early amyloid deposition predicts cognitive decline in subjects with aMCI, with a higher rate of decline in those with SUVr above a threshold of 1.21. Detection of early amyloid positivity may help in selecting the target population for preventive therapeutic interventions and in designing treatment trials (Trial number, EudraCT 2015-001184-39).

Validation of a performance-based assessment of cognitive functional ability in Parkinson's disease

BACKGROUND

Outcome measures that capture functional abilities related to cognition offer the potential to demonstrate real-world effectiveness of cognitive-enhancing treatments. However, distinguishing functional disability related to cognition from that attributed to motor symptoms can be difficult in PD. A performance-based functional assessment allows for direct observation of activity of daily living skills and separation of cognitive from motoric disabilities.

OBJECTIVES

Validate the University of California San Diego Performance-Based Skills Assessment in PD.

METHODS

One hundred PD participants, ranging from normal cognition to dementia, completed the University of California San Diego Performance-Based Skills Assessment, a performance-based measure of cognitively demanding activities of daily living, as well as a neuropsychological battery and motor examination. Cognitive classification was determined by consensus conference, blinded to University of California San Diego Performance-Based Skills Assessment scores. Psychometric properties of the University of California San Diego Performance-Based Skills Assessment, including internal consistency, test-retest and inter-rater reliability, and discriminant validity for dementia, were examined.

RESULTS

The University of California San Diego Performance-Based Skills Assessment demonstrated strong internal consistency (Cronbach's α = 0.82) and test-retest reliability (r = 0.89) and correlated strongly with global cognition (Mattis Dementia Rating Scale: r = 0.80; P < 0.001). University of California San Diego Performance-Based Skills Assessment regression models indicated greater contribution from cognitive explanatory variables (marginal partial: R2  = 0.33) than motor variables (marginal partial: R2  = 0.05), controlling for age, education, disease duration, and l-dopa equivalent dose. Additionally, the University of California San Diego Performance-Based Skills Assessment exhibited strong discriminant validity for dementia (area under the curve = 0.91).

CONCLUSIONS

The University of California San Diego Performance-Based Skills Assessment is a valid measure of functional abilities related to cognition rather than motor symptoms in PD. Furthermore, it reliably distinguishes demented from nondemented participants. The University of California San Diego Performance-Based Skills Assessment may be considered as an outcome measure that combines cognitive and functional abilities in treatment trials for cognitive impairment in PD. © 2018 International Parkinson and Movement Disorder Society.

Problem-Solving Therapy Reduces Suicidal Ideation In Depressed Older Adults with Executive Dysfunction

OBJECTIVE

To test the hypothesis that Problem Solving Therapy (PST) is more effective than Supportive Therapy (ST) in reducing suicidal ideation in older adults with major depression and executive dysfunction. We further explored whether patient characteristics, such as age, sex, and additional cognitive impairment load (e.g., memory impairments) were related to changes in suicidal ideation over time.

DESIGN

Secondary data analysis using data from a randomized clinical trial allocating participants to PST or ST at 1:1 ratio. Raters were blind to patients' assignments.

SETTING

University medical centers.

PARTICIPANTS

221 people aged 65 years old and older with major depression determined by Structured Clinical Interview for DSM-III-R diagnosis and executive dysfunction as defined by a score of 33 or less on the Initiation-Perseveration Score of the Mattis Dementia Rating Scale or a Stroop Interference Task score of 25 or less.

INTERVENTIONS

12 weekly sessions of PST or ST.

MAIN OUTCOME MEASURES

The suicide item of the Hamilton Depression Rating Scale.

RESULTS

Of the 221 participants, 61% reported suicidal ideation (SI). The ST group had a lower rate of improvement in SI after 12 weeks (44.6%) than did the PST group (60.4%, Fisher's exact test p = 0.031). Logistic regression showed significantly greater reductions in SI in elders who received PST at both 12 weeks (OR: .50, Z = -2.16, p = 0.031) and 36 weeks (OR: 0.5, Z = -1.96, p = 0.05) after treatment.

CONCLUSIONS

PST is a promising intervention for older adults who are at risk for suicide. ClinicalTrials.gov Identifier: NCT00052091.

Clinical validity of the Mattis Dementia Rating Scale in differentiating mild cognitive impairment in Parkinson's disease and normative data

BACKGROUND/AIMS

The aim of the present study was to provide normative data and determine the validity of the Czech version of the Mattis Dementia Rating Scale 2 (czDRS-2) in screening for mild cognitive impairment in Parkinson's disease (PD-MCI) based on the Movement Disorder Society (MDS) Level II criteria.

METHODS

For validation purposes, 41 healthy controls (HC), 46 patients with PD-NI (Parkinson's disease, no impairment) and 41 patients with PD-MCI (all groups assessed by the MDS Level II criteria for PD-MCI) were matched according to age and education.

RESULTS

With screening and diagnostic cutoff scores determined at ≤139 points, the czDRS-2 showed a sensitivity of 78% and a specificity of 88% in the detection of PD-MCI versus HC and a sensitivity of 78% and a specificity of 76% in the detection of PD-MCI versus PD-NI. The AUC (95% confidence interval) for the czDRS-2 was 84% (75-93) and 82% (73-91), respectively. We report percentile values for 286 subjects from the Czech population stratified by education level.

CONCLUSION

Our results show that the czDRS-2 is a valid instrument at Level I for screening PD-MCI and support its construct validity and diagnostic equivalence in a cross-cultural setting.

The diagnostic accuracy of dementia-screening instruments with an administration time of 10 to 45 minutes for use in secondary care: a systematic review

Early screening for dementia is crucial for identifying reversible causes as well as managing, counseling, and other therapeutic interventions. Many reviews have compared the suitability of very brief screening instruments for use in primary care, but reviews on more extensive instruments in secondary care are scarce. In addition, results on diagnostic accuracy are often biased due to methodological shortcomings, differences in the spectrum of patients or reporting. This systematic review reports the diagnostic accuracy of dementia-screening instruments with an administration time of 10 to 45 minutes, validated in secondary care, restricted to mild dementia and validation studies of ''high quality.'' Characteristics such as cognitive domains and reliability figures are also highlighted.

Construct and Concurrent Validity of the Dementia Rating Scale-2 Alternate Form

The Dementia Rating Scale-2: Alternate Form (DRS-2: AF) was developed by Schmidt (2004) for use in serial neuropsychological assessments with the original DRS-2 (Jurica, Leitten, & Mattis, 2001). Results from two preliminary validation studies of the DRS-2: AF are presented here. In Study 1, the DRS-2: AF and four additional neuropsychological measures were administered to 49 healthy, community-dwelling participants without dementia; convergent and discriminant correlational analyses provide evidence for the construct validity of four DRS-2: AF subscales (Attention, Initiation/ Perseveration, Conceptualization, Memory). In Study 2, the DRS-2: AF and Mini-Mental State Examination (MMSE) were administered to a sample of 65 residents living in a continuing care retirement community (30 residents with dementia, 35 residents without dementia) to demonstrate the construct and concurrent validity of the DRS-2: AF Total Score. A strong correlation was found between the MMSE and DRS-2: AF Total Score. When DRS-2: AF Total Scores were subjected to a discriminant function analysis, Total Scores accurately classified 61 of the 65 participants into the appropriate patient group (dementia vs. comparison). The results of these preliminary validation studies are robust, and suggest that the DRS-2: AF may be a useful measure when serial assessments with the DRS-2 are needed.

Improvements in cognition in patients converting from thrice weekly hemodialysis to nocturnal hemodialysis: a longitudinal pilot study

Cognitive impairment has been documented in uremia with partial improvement after dialysis. Nocturnal daily hemodialysis (NHD) is a novel dialysis modality with multiple benefits. Previous reports have shown marked improvements in quality of life, cardiac function, resolution of peripheral vascular disease, and reversal of central sleep apnea. We hypothesized that patients maintained on NHD would have better cognitive functioning than those receiving conventional therapy. Using a longitudinal study design, patients were tested at baseline and again after >or=6 months NHD. At each of the two time points, a battery of 10 neuropsychological tests were used to evaluate three domains of cognitive functioning--attention and working memory skills, psychomotor efficiency and processing speed, and learning efficiency. Clinical subjective symptoms for cognitive functioning and depression were measured using the Patients Assessment of Own Functioning inventory and the Beck Depression Index. Twelve patients (six males, six females) were recruited. Patients were aged 39.6+/-3.3 years at the time of first testing. Thirty-three percent were diabetic, with a mean Charlson comorbidity score of 3.5+/-2.0. Depression (defined as >16 on the Beck Depression Index score) was not seen in any patient. Over the 6-month period, a 22% reduction in cognitive symptoms (P=0.01), 7% improvement in psychomotor efficiency and processing speed (P=0.02), and 32% improvement in attention and working memory (P=0.04) was seen. Learning efficiency scores were unchanged. NHD may be associated with improved general cognitive efficiency as measured by psychomotor efficiency and attention and working memory.