Level I PD‐MCI using global cognitive tests and the risk for Parkinson's disease dementia

Background

The criteria for PD‐MCI allow the use of global cognitive tests. Their predictive value for conversion from PD‐MCI to PDD, especially compared to comprehensive neuropsychological assessment, is unknown.

Methods

The MDS PD‐MCI Study Group combined four datasets containing global cognitive tests as well as a comprehensive neuropsychological assessment to define PD‐MCI (n = 467). Risk for developing PDD was examined using a Cox model. Global cognitive tests were compared to neuropsychological test batteries (Level I&II) in determining risk for PDD.

Results

PD‐MCI based on a global cognitive test (MMSE or MoCA) increases the hazard for developing PDD (respectively HR = 2.57, P = 0.001; HR = 4.14, P = <0.001). The C‐statistics for MMSE (0.72) and MoCA (0.70) were lower than those based on neuropsychological tests (Level I = 0.82; Level II = 0.81). Sensitivity, specificity and diagnostic accuracy balance was best in Level II.

Conclusion

MMSE and MoCA predict conversion to PDD. However, Level II neuropsychological assessment seems the preferred assessment for PD‐MCI.

Rivastigmine for minor visual hallucinations in Parkinson's disease: A randomized controlled trial with 24 months follow-up

BACKGROUND

Visual hallucinations are common in patients with Parkinson's disease and represent probably the major independent predictor for cognitive deterioration and nursing home placement.

OBJECTIVE

To investigate if treatment of minor visual hallucinations in Parkinson's disease with rivastigmine delays the progression to psychosis.

METHODS

A multicenter, randomized, double-blind, placebo-controlled trial was conducted which aimed to recruit 168 patients with Parkinson's disease reporting minor visual hallucinations 4 weeks before it. Important exclusion criteria were Parkinson's disease dementia, current delirium, and treatment with antipsychotics or drugs that have significant anti-cholinergic side effects. Subjects were randomized to rivastigmine capsules, 3-6 mg twice a day, or placebo for 24 months. The primary outcome was the time to Parkinson's disease psychosis, which was defined as the need to start with antipsychotics.

RESULTS

The trial was stopped prematurely because of slow recruitment. Ninety-one patients were randomized: 46 patients were assigned to rivastigmine and 45 patients to placebo. No effect of rivastigmine could be demonstrated on the transition time to psychosis or dementia during the 24-month follow-up period. After 6 months of study treatment, cognition, mood, motor performance, and non-motor performance did not differ significantly between the rivastigmine-group and the placebo-group.

CONCLUSIONS

Because the study was terminated early, it was insufficiently powered to properly evaluate the primary outcome. The limited data of the study favor a wait and see approach instead of early treatment with rivastigmine in PD patients with minor VH.

Screening for cognition in amyotrophic lateral sclerosis: test characteristics of a new screen

Cognitive and behavioural impairment in amyotrophic lateral sclerosis (ALS) negatively influences the quality of life and survival, and, therefore, screening for these impairments is recommended. We developed a cognitive screening tool, the amyotrophic lateral sclerosis–frontotemporal dementia–cognitive screen (ALS–FTD–Cog) and aimed to validate it in patients with ALS. During the current study, the Edinburgh Cognitive and Behavioural ALS Screen (ECAS) was published and we, therefore, decided to compare these two cognitive screening methods. The ALS–FTD–Cog was administered to 72 patients with ALS, 21 patients with behavioural variant FTD (bvFTD) and 34 healthy controls. Twenty-nine patients with ALS underwent the ECAS. ROC curve analyses were performed and sensitivity and specificity of the ALS–FTD–Cog and ECAS were calculated, with a neuropsychological examination (NPE) as the gold standard. Cognitive impairment was present in 28% of patients with ALS. ROC curve analyses of the ALS–FTD–Cog and ECAS showed an area under the curve (AUC) of 0.72 (95% CI 0.58–0.86) and 0.95 (95% CI 0.86–1.03), respectively. Compared to a full NPE, sensitivity and specificity of the ALS–FTD–Cog were 65.0% and 63.5% and of the ECAS 83.3% and 91.3%, respectively. The sensitivity and specificity of the ALS–FTD–Cog in patients with bvFTD were 94.4% and 100%, respectively. Test characteristics of the ALS–FTD–Cog were moderate, suggesting restricted practical value, as compared to a comprehensive NPE. The ECAS had an excellent AUC and high sensitivity and specificity, indicating that it is a valid screening instrument for cognitive impairment in ALS.

Association of Cognitive Function Trajectories in Centenarians With Postmortem Neuropathology, Physical Health, and Other Risk Factors for Cognitive Decline

IMPORTANCE

Understanding mechanisms associated with prolonged cognitive health in combination with exceptional longevity might lead to approaches to enable successful aging.

OBJECTIVE

To investigate trajectories of cognitive functioning in centenarians across domains, and to examine the association of these trajectories with factors underlying cognitive reserve, physical health, and postmortem levels of Alzheimer disease (AD)-associated neuropathology.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used neuropsychological test data and postmortem neuropathological reports from Dutch centenarians who were drawn from the 100-plus Study between January 2013 and April 2019. Eligible participants self-reported being cognitively healthy, which was confirmed by a proxy. Data analysis was performed between June 2019 and June 2020.

EXPOSURES

Age, sex, APOE ε genotype, factors of cognitive reserve, physical health, and AD-associated neuropathology (ie, amyloid-β, neurofibrillary tangles, and neuritic plaques).

MAIN OUTCOMES AND MEASURES

In annual visits (until death or until participation was no longer possible), centenarians underwent an extensive neuropsychological test battery, from which an mean z score of global cognition, memory, executive functions, verbal fluency, visuospatial functions, and attention/processing speed was calculated. Linear mixed models with a random intercept and time as independent variable were used to investigate cognitive trajectories, adjusted for sex, age, education, and vision and hearing capacities. In a second step, linear mixed models were used to associate cognitive trajectories with factors underlying cognitive reserve, physical health at baseline, and AD-associated neuropathology.

RESULTS

Of the 1023 centenarians approached, 340 were included in the study. We analyzed 330 centenarians for whom cognitive tests were available at baseline (239 [72.4%] women; median [interquartile range] age of 100.5 [100.2-101.7] years), with a mean (SD) follow-up duration of 1.6 (0.8) years. We observed no decline across investigated cognitive domains, with the exception of a slight decline in memory function (β, -0.10 SD per year; 95% CI, -0.14 to -0.05 SD; P < .001). Cognitive performance was associated with factors of physical health (eg, higher Barthel index: β, 0.37 SD per year; 95% CI, 0.24-0.49; P < .001) and cognitive reserve (eg, higher education: β, 0.41 SD per year; 95% CI, 0.29-0.53; P < .001), but none of these factors were associated with the rate of decline. Neuropathological reports were available for 44 participants. While centenarian brains revealed varying loads of postmortem neuropathological hallmarks of AD, this was not associated with cognitive performance or rate of decline.

CONCLUSIONS AND RELEVANCE

While we observed a slight vulnerability for decline in memory function, centenarians maintained high levels of performance in all other investigated cognitive domains for up to 4 years despite the presence of risk factors of cognitive decline. These findings suggest that mechanisms of resilience may underlie the prolongation of cognitive health until exceptional ages.

An Operational Definition of 'Abnormal Cognition' to Optimize the Prediction of Progression to Dementia: What Are Optimal Cut-Off Points for Univariate and Multivariate Normative Comparisons?

Background:

In neuropsychology and neurology, there is no consensus on the definition of abnormal cognition.

Objective:

To operationally define ‘abnormal cognition’ for optimally predicting progression to dementia in a memory clinic sample, and to test whether multivariate profile analysis of cognitive test results improves this prediction compared to standard clinical evaluation.

Methods:

We used longitudinal data from 835 non-demented patients of the Amsterdam Dementia Cohort. For 10 cognitive measures at baseline, we determined which number of abnormal tests and which magnitude of score deviations best predicted progression.

Results:

Predictive ability for progression to dementia of one, two, and three abnormal test scores out of 10 is highly similar (Cox hazard ratios: 3.7–4.1) provided cut-off values are adapted appropriately. Cut-offs have to be less stringent if the number of abnormal tests required increases: the optimal cut-off is z < –1.45 when one deviating score is required, z < –1.15 when two abnormal tests are required, and z < –0.70 when three abnormal tests are required. The profile analysis has similar predictive ability at the cut-off of p < 0.22 (hazard ratio 3.8). A likelihood ratio test showed that this analysis improves prediction of progression to dementia when added to standard clinical evaluation (p < 0.001).

Conclusion:

Abnormal cognition may be defined as one, two, or three abnormal test scores out of 10 if the magnitude of score deviations is adapted accordingly. An abnormal score profile predicts decline to dementia equally well, and improves the prediction when used complimentary to standard clinical evaluation.

The Factor Structure of Cognitive Functioning in Cognitively Healthy Participants: a Meta-Analysis and Meta-Analysis of Individual Participant Data

Many neuropsychologists are of the opinion that the multitude of cognitive tests may be grouped into a much smaller number of cognitive domains. However, there is little consensus on how many domains exist, what these domains are, nor on which cognitive tests belong to which domain. This incertitude can be solved by factor analysis, provided that the analysis includes a broad range of cognitive tests that have been administered to a very large number of people. In this article, two such factor analyses were performed, each combining multiple studies. However, because it was not possible to obtain complete multivariate data on more than the most common test variables in the field, not all possible domains were examined here. The first analysis was a factor meta-analysis of correlation matrices combining data of 60,398 healthy participants from 52 studies. Several models from the literature were fitted, of which a version based on the Cattell-Horn-Carroll (CHC) model was found to describe the correlations better than the others. The second analysis was a factor analysis of the Advanced Neuropsychological Diagnostics Infrastructure (ANDI) database, combining scores of 11,881 participants from 54 Dutch and Belgian studies not included in the first meta-analysis. Again, the model fit was better for the CHC model than for other models. Therefore, we conclude that the CHC model best characterizes both cognitive domains and which test belongs to each domain. Therefore, although originally developed in the intelligence literature, the CHC model deserves more attention in neuropsychology.

Validation of a Novel Multivariate Method of Defining HIV-Associated Cognitive Impairment

BACKGROUND

The optimum method of defining cognitive impairment in virally suppressed people living with HIV is unknown. We evaluated the relationships between cognitive impairment, including using a novel multivariate method (NMM), patient- reported outcome measures (PROMs), and neuroimaging markers of brain structure across 3 cohorts.

METHODS

Differences in the prevalence of cognitive impairment, PROMs, and neuroimaging data from the COBRA, CHARTER, and POPPY cohorts (total n = 908) were determined between HIV-positive participants with and without cognitive impairment defined using the HIV-associated neurocognitive disorders (HAND), global deficit score (GDS), and NMM criteria.

RESULTS

The prevalence of cognitive impairment varied by up to 27% between methods used to define impairment (eg, 48% for HAND vs 21% for NMM in the CHARTER study). Associations between objective cognitive impairment and subjective cognitive complaints generally were weak. Physical and mental health summary scores (SF-36) were lowest for NMM-defined impairment ( P < .05).There were no differences in brain volumes or cortical thickness between participants with and without cognitive impairment defined using the HAND and GDS measures. In contrast, those identified with cognitive impairment by the NMM had reduced mean cortical thickness in both hemispheres ( P < .05), as well as smaller brain volumes ( P < .01). The associations with measures of white matter microstructure and brain-predicted age generally were weaker.

CONCLUSION

Different methods of defining cognitive impairment identify different people with varying symptomatology and measures of brain injury. Overall, NMM-defined impairment was associated with most neuroimaging abnormalities and poorer self-reported health status. This may be due to the statistical advantage of using a multivariate approach.

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

BACKGROUND

The International Parkinson and Movement Disorders Society criteria for mild cognitive impairment in PD need validation. The objectives of this present study were to evaluate prognostic validity of level I (abbreviated) International Parkinson and Movement Disorders Society mild cognitive impairment in PD criteria for development of PD dementia and compared them with level II (comprehensive) criteria.

METHODS

We analyzed data from 8 international studies (1045 patients) from our consortium that included baseline data on demographics, motor signs, depression, detailed neuropsychological testing, and longitudinal follow-up for conversion to Parkinson's disease dementia. Survival analysis evaluated their contribution to the hazard of Parkinson's disease dementia.

RESULTS

Level I mild cognitive impairment in PD, increasing age, male sex, and severity of PD motor signs independently increased the hazard of Parkinson's disease dementia. Level I and level II mild cognitive impairment in PD classification had similar discriminative ability with respect to the time to Parkinson's disease dementia.

CONCLUSIONS

Level I mild cognitive impairment in PD classification independently contributes to the hazard of Parkinson's disease dementia. This finding supports the prognostic validity of the abbreviated mild cognitive impairment in PD criteria. © 2019 International Parkinson and Movement Disorder Society.

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

BACKGROUND

Numerous neuropsychological tests and test versions are used in Parkinson's disease research, but their relative capacity to detect mild cognitive deficits and their comparability across studies are unknown. The objective of this study was to identify neuropsychological tests that consistently detect cognitive decline in PD across studies.

METHODS

Data from 30 normed neuropsychological tests across 20 international studies in up to 2908 nondemented PD patients were analyzed. A subset of 17 tests was administered to up to 1247 healthy controls. A 2-step meta-analytic approach using standardized scores compared performance in PD with normative data.

RESULTS

Pooled estimates of the differences between PD and site-specific healthy controls identified significant cognitive deficits in PD patients on 14 test scores across 5 commonly assessed cognitive domains (attention or working memory, executive, language, memory, and visuospatial abilities), but healthy control performance was statistically above average on 7 of these tests. Analyses based on published norms only, as opposed to direct assessment of healthy controls, showed high between-study variability that could not be accounted for and led to inconclusive results.

CONCLUSIONS

Normed neuropsychological tests across multiple cognitive domains consistently detect cognitive deficits in PD when compared with site-specific healthy control performance, but relative PD performance was significantly affected by the inclusion and type of healthy controls versus the use of published norms only. Additional research is needed to identify a cognitive battery that can be administered in multisite international studies and that is sensitive to cognitive decline, responsive to therapeutic interventions, and superior to individual cognitive tests. © 2018 International Parkinson and Movement Disorder Society.

Electrode Penetration of the Caudate Nucleus in Deep Brain Stimulation Surgery for Parkinson's Disease

OBJECTIVE

To evaluate the possible influence of electrode trajectories penetrating the caudate nucleus (CN) on cognitive outcomes in deep brain stimulation (DBS) surgery for Parkinson's disease (PD).

BACKGROUND

It is currently unclear how mandatory CN avoidance during trajectory planning is.

DESIGN/METHODS

Electrode trajectories were determined to be inside, outside, or in border region of the CN. Pre- and postoperative neuropsychological tests of each trajectory group were compared in order to evaluate possible differences in cognitive outcomes 12 months after bilateral STN DBS.

RESULTS

One hundred six electrode tracks in 53 patients were evaluated. Bilateral penetration of the CN occurred in 15 (28%) patients, while unilateral penetration occurred in 28 (53%). In 19 (36%) patients tracks were located in the border region of the CN. There was no electrode penetration of the CN in 10 (19%) patients. No difference in cognitive outcomes was found between the different groups.

CONCLUSION

Cognitive outcome was not influenced by DBS electrode tracks penetrating the CN. It is both feasible and sensible to avoid electrode tracks through the CN when possible, considering its function and anatomical position. However, penetration of the CN can be considered without major concerns regarding cognitive decline when this facilitates optimal trajectory planning due to specific individual anatomical variations.

The cognitive profile of behavioural variant FTD and its similarities with ALS: a systematic review and meta-analysis

Approximately 30% of patients with amyotrophic lateral sclerosis (ALS) have cognitive impairment and 8%-14% fulfil the criteria for behavioural variant frontotemporal dementia (bv-FTD). The cognitive profiles of ALS and bv-FTD have been reported to be comparable, but this has never been systematically investigated. We aimed to determine the cognitive profile of bv-FTD and examine its similarities with that of ALS, to provide evidence for the existence of a cognitive disease continuum encompassing bv-FTD and ALS. We therefore systematically reviewed neuropsychological studies on bv-FTD patients and healthy volunteers. Neuropsychological tests were divided in 10 cognitive domains and effect sizes were calculated for all domains and compared with the cognitive profile of ALS by means of a visual comparison and a Pearson's r correlation coefficient. We included 120 studies, totalling 2425 bv-FTD patients and 2798 healthy controls. All cognitive domains showed substantial effect sizes, indicating cognitive impairment in bv-FTD patients compared to healthy controls. The cognitive domains with the largest effect sizes were social cognition, verbal memory and fluency (1.77-1.53). The cognitive profiles of bv-FTD and ALS (10 cognitive domains, 1287 patients) showed similarities on visual comparison and a moderate correlation 0.58 (p=0.13). When social cognition, verbal memory, fluency, executive functions, language and visuoperception were considered, i.e. the cognitive profile of ALS, Pearson's r was 0.73 (p=0.09), which raised to 0.92 (p=0.03), when language was excluded in this systematic analysis of patients with a non-language subtype of FTD. The cognitive profile of bv-FTD consists of deficits in social cognition, verbal memory, fluency and executive functions and shows similarities with the cognitive profile of ALS. These findings support a cognitive continuum encompassing ALS and bv-FTD.

Gray and White Matter Abnormalities in Treated Human Immunodeficiency Virus Disease and Their Relationship to Cognitive Function

Background

Long-term comorbidities such as cognitive impairment remain prevalent in otherwise effectively treated people living with human immunodeficiency virus (HIV). We investigate the relationship between cognitive impairment and brain structure in successfully treated patients using multimodal neuroimaging from the Comorbidity in Relation to AIDS (COBRA) cohort.

Methods

Cognitive function, brain tissue volumes, and white matter microstructure were assessed in 134 HIV-infected patients and 79 controls. All patients had suppressed plasma HIV RNA at cohort entry. In addition to comprehensive voxelwise analyses of volumetric and diffusion tensor imaging, we used an unsupervised machine learning approach to combine cognitive, diffusion, and volumetric data, taking advantage of the complementary information they provide.

Results

Compared to the highly comparable control group, cognitive function was impaired in 4 of the 6 cognitive domains tested (median global T-scores: 50.8 vs 54.2; P < .001). Patients had lower gray but not white matter volumes, observed principally in regions where structure generally did not correlate with cognitive function. Widespread abnormalities in white matter microstructure were also seen, including reduced fractional anisotropy with increased mean and radial diffusivity. In contrast to the gray matter, these diffusion abnormalities correlated with cognitive function. Multivariate neuroimaging analysis identified a neuroimaging phenotype associated with poorer cognitive function, HIV infection, and systemic immune activation.

Conclusions

Cognitive impairment, lower gray matter volume, and white matter microstructural abnormalities were evident in HIV-infected individuals despite fully suppressive antiretroviral therapy. White matter abnormalities appear to be a particularly important determinant of cognitive dysfunction seen in well-treated HIV-infected individuals.

Multivariate normative comparisons for neuropsychological assessment by a multilevel factor structure or multiple imputation approach

Neuropsychologists administer neuropsychological tests to decide whether a patient is cognitively impaired. This clinical decision is made by comparing a patient's scores to those of healthy participants in a normative sample. In a multivariate normative comparison, a patient's entire profile of scores is compared to scores in a normative sample. Such a multivariate comparison has been shown to improve clinical decision making. However, it requires a multivariate normative data set, which often is unavailable. To obtain such a multivariate normative data set, the authors propose to aggregate healthy control group data from existing neuropsychological studies. As not all studies administered the same tests, this aggregated database will contain substantial amounts of missing data. The authors therefore propose two solutions: multiple imputation and factor modeling. Simulation studies show that factor modeling is preferred over multiple imputation, provided that the factor model is adequately specified. This factor modeling approach will therefore allow routine use of multivariate normative comparisons, enabling more accurate clinical decision making. (PsycINFO Database Record

Increased brain-predicted aging in treated HIV disease

OBJECTIVE

To establish whether HIV disease is associated with abnormal levels of age-related brain atrophy, by estimating apparent brain age using neuroimaging and exploring whether these estimates related to HIV status, age, cognitive performance, and HIV-related clinical parameters.

METHODS

A large sample of virologically suppressed HIV-positive adults (n = 162, age 45-82 years) and highly comparable HIV-negative controls (n = 105) were recruited as part of the Comorbidity in Relation to AIDS (COBRA) collaboration. Using T1-weighted MRI scans, a machine-learning model of healthy brain aging was defined in an independent cohort (n = 2,001, aged 18-90 years). Neuroimaging data from HIV-positive and HIV-negative individuals were then used to estimate brain-predicted age; then brain-predicted age difference (brain-PAD = brain-predicted brain age - chronological age) scores were calculated. Neuropsychological and clinical assessments were also carried out.

RESULTS

HIV-positive individuals had greater brain-PAD score (mean ± SD 2.15 ± 7.79 years) compared to HIV-negative individuals (-0.87 ± 8.40 years; b = 3.48, p < 0.01). Increased brain-PAD score was associated with decreased performance in multiple cognitive domains (information processing speed, executive function, memory) and general cognitive performance across all participants. Brain-PAD score was not associated with age, duration of HIV infection, or other HIV-related measures.

CONCLUSION

Increased apparent brain aging, predicted using neuroimaging, was observed in HIV-positive adults, despite effective viral suppression. Furthermore, the magnitude of increased apparent brain aging related to cognitive deficits. However, predicted brain age difference did not correlate with chronological age or duration of HIV infection, suggesting that HIV disease may accentuate rather than accelerate brain aging.

Exploring possible predictors and moderators of an executive function training for children with an autism spectrum disorder

Previously, a total of 121 children with an autism spectrum disorder (ASD) performed an adaptive working memory (WM)-training, an adaptive flexibility-training, or a non-adaptive control (mock)-training. Despite overall improvement, there were minor differences between the adaptive and mock-training conditions. Moreover, dropout was relatively high (26%). In the current study we explored potential predicting and moderating factors to clarify these findings. The effects of intelligence, autism traits, WM, flexibility, reward sensitivity and Theory of Mind on dropout, improvement during training, and improvement in everyday executive functioning (EF), ASD-like behavior, and Quality of Life (QoL) were studied. None of the predictors influenced dropout or training improvement. However, 1) more pre-training autism traits related to less improvement in EF and QoL, and 2) higher reward sensitivity was related to more improvement in QoL and ASD-like behavior. These findings suggest that these EF-training procedures may be beneficial for children with fewer autism traits and higher reward sensitivity. However, the exploratory nature of the analyses warrant further research before applying the findings clinically.

Indicators of suboptimal performance embedded in the Wechsler Memory Scale-Fourth Edition (WMS-IV)

INTRODUCTION

Recognition and visual working memory tasks from the Wechsler Memory Scale-Fourth Edition (WMS-IV) have previously been documented as useful indicators for suboptimal performance. The present study examined the clinical utility of the Dutch version of the WMS-IV (WMS-IV-NL) for the identification of suboptimal performance using an analogue study design.

METHOD

The patient group consisted of 59 mixed-etiology patients; the experimental malingerers were 50 healthy individuals who were asked to simulate cognitive impairment as a result of a traumatic brain injury; the last group consisted of 50 healthy controls who were instructed to put forth full effort.

RESULTS

Experimental malingerers performed significantly lower on all WMS-IV-NL tasks than did the patients and healthy controls. A binary logistic regression analysis was performed on the experimental malingerers and the patients. The first model contained the visual working memory subtests (Spatial Addition and Symbol Span) and the recognition tasks of the following subtests: Logical Memory, Verbal Paired Associates, Designs, Visual Reproduction. The results showed an overall classification rate of 78.4%, and only Spatial Addition explained a significant amount of variation (p < .001). Subsequent logistic regression analysis and receiver operating characteristic (ROC) analysis supported the discriminatory power of the subtest Spatial Addition. A scaled score cutoff of <4 produced 93% specificity and 52% sensitivity for detection of suboptimal performance.

CONCLUSION

The WMS-IV-NL Spatial Addition subtest may provide clinically useful information for the detection of suboptimal performance.

Advanced Neuropsychological Diagnostics Infrastructure (ANDI): A Normative Database Created from Control Datasets

In the Advanced Neuropsychological Diagnostics Infrastructure (ANDI), datasets of several research groups are combined into a single database, containing scores on neuropsychological tests from healthy participants. For most popular neuropsychological tests the quantity, and range of these data surpasses that of traditional normative data, thereby enabling more accurate neuropsychological assessment. Because of the unique structure of the database, it facilitates normative comparison methods that were not feasible before, in particular those in which entire profiles of scores are evaluated. In this article, we describe the steps that were necessary to combine the separate datasets into a single database. These steps involve matching variables from multiple datasets, removing outlying values, determining the influence of demographic variables, and finding appropriate transformations to normality. Also, a brief description of the current contents of the ANDI database is given.

The frontotemporal syndrome of ALS is associated with poor survival

Thirty percent of ALS patients have a frontotemporal syndrome (FS), defined as behavioral changes or cognitive impairment. Despite previous studies, there are no firm conclusions on the effect of the FS on survival and the use of non-invasive ventilation (NIV) in ALS. We examined the effect of the FS on survival and the start and duration of NIV in ALS. Behavioral changes were defined as >22 points on the ALS-Frontotemporal-Dementia-Questionnaire or ≥3 points on ≥2 items of the Neuropsychiatric Inventory. Cognitive impairment was defined as below the fifth percentile on ≥2 tests of executive function, memory or language. Classic ALS was defined as ALS without the frontotemporal syndrome. We performed survival analyses from symptom onset and time from NIV initiation, respectively, to death. The impact of the explanatory variables on survival and NIV initiation were examined using Cox proportional hazards models. We included 110 ALS patients (76 men) with a mean age of 62 years. Median survival time was 4.3 years (95 % CI 3.53–5.13). Forty-seven patients (43 %) had an FS. Factors associated with shorter survival were FS, bulbar onset, older age at onset, short time to diagnosis and a C9orf72 repeat expansion. The adjusted hazard ratio (HR) for the FS was 2.29 (95 % CI 1.44–3.65, p < 0.001) in a multivariate model. Patients with an FS had a shorter survival after NIV initiation (adjusted HR 2.70, 95 % CI 1.04–4.67, p = 0.04). In conclusion, there is an association between the frontotemporal syndrome and poor survival in ALS, which remains present after initiation of NIV.

The cognitive profile of ALS: a systematic review and meta-analysis update

Cognitive impairment is present in approximately 30% of patients with amyotrophic lateral sclerosis (ALS) and, especially when severe, has a negative impact on survival and caregiver burden. Our 2010 meta-analysis of the cognitive profile of ALS showed impairment of fluency, executive function, language and memory. However, the limited number of studies resulted in large confidence intervals. To obtain a more valid assessment, we updated the meta-analysis and included methodological improvements (controlled data extraction, risk of bias analysis and effect size calculation of individual neuropsychological tests). Embase, Medline and PsycInfo were searched for neuropsychological studies of non-demented patients with ALS and age-matched and education-matched healthy controls. Neuropsychological tests were categorised in 13 cognitive domains and effect sizes (Hedges' g) were calculated for each domain and for individual tests administered in ≥5 studies. Subgroup analyses were performed to assess the influence of clinical and demographic variables. Forty-four studies were included comprising 1287 patients and 1130 healthy controls. All cognitive domains, except visuoperceptive functions, showed significant effect sizes compared to controls. Cognitive domains without bias due to motor impairment showed medium effect sizes (95% CI): fluency (0.56 (0.43 to 0.70)), language (0.56 (0.40 to 0.72)), social cognition (0.55 (0.34 to 0.76)), or small effect sizes: delayed verbal memory 0.47 (0.27 to 0.68)) and executive functions (0.41 (0.27 to 0.55)). Individual neuropsychological tests showed diverging effect sizes, which could be explained by bias due to motor impairment. Subgroup analyses showed no influence of bulbar disease onset and depression and anxiety on the cognitive outcomes. The cognitive profile of ALS consists of deficits in fluency, language, social cognition, executive functions and verbal memory. Social cognition is a new cognitive domain with a relatively large effect size, highlighting the overlap between ALS and frontotemporal dementia. The diverging effect sizes for individual neuropsychological tests show the importance of correction for motor impairment in patients with ALS. These findings have implications for bedside testing, the design of cognitive screening measures and full neuropsychological examinations.

Computer-Based Cognitive Training for Executive Functions after Stroke: A Systematic Review

Background: Stroke commonly results in cognitive impairments in working memory, attention, and executive function, which may be restored with appropriate training programs. Our aim was to systematically review the evidence for computer-based cognitive training of executive dysfunctions.

Methods: Studies were included if they concerned adults who had suffered stroke or other types of acquired brain injury, if the intervention was computer training of executive functions, and if the outcome was related to executive functioning. We searched in MEDLINE, PsycINFO, Web of Science, and The Cochrane Library. Study quality was evaluated based on the CONSORT Statement. Treatment effect was evaluated based on differences compared to pre-treatment and/or to a control group.

Results: Twenty studies were included. Two were randomized controlled trials that used an active control group. The other studies included multiple baselines, a passive control group, or were uncontrolled. Improvements were observed in tasks similar to the training (near transfer) and in tasks dissimilar to the training (far transfer). However, these effects were not larger in trained than in active control groups. Two studies evaluated neural effects and found changes in both functional and structural connectivity. Most studies suffered from methodological limitations (e.g., lack of an active control group and no adjustment for multiple testing) hampering differentiation of training effects from spontaneous recovery, retest effects, and placebo effects.

Conclusions: The positive findings of most studies, including neural changes, warrant continuation of research in this field, but only if its methodological limitations are addressed.

GPi vs STN deep brain stimulation for Parkinson disease: Three-year follow-up

OBJECTIVE

To compare motor symptoms, cognition, mood, and behavior 3 years after deep brain stimulation (DBS) of the globus pallidus pars interna (GPi) and subthalamic nucleus (STN) in advanced Parkinson disease (PD).

METHODS

Patients with PD eligible for DBS were randomized to bilateral GPi DBS and bilateral STN DBS (1:1). The primary outcome measures were (1) improvement in motor symptoms in off-drug phase measured with the Unified Parkinson Disease Rating Scale (UPDRS) and (2) a composite score for cognitive, mood, and behavioral effects, and inability to complete follow-up at 36 months after surgery.

RESULTS

Of the 128 patients enrolled, 90 were able to complete the 3-year follow-up. We found significantly more improvement of motor symptoms after STN DBS (median [interquartile range (IQR)] at 3 years, GPi 33 [23-41], STN 28 [20-36], p = 0.04). No between-group differences were observed on the composite score (GPi 83%, STN 86%). Secondary outcomes showed larger improvement in off-drug functioning in the AMC Linear Disability Scale score after STN DBS (mean ± SD, GPi 65.2 ± 20.1, STN 72.6 ± 18.0, p = 0.05). Medication was reduced more after STN DBS (median levodopa equivalent dose [IQR] at 3 years, GPi 1,060 [657-1,860], STN 605 [411-875], p < 0.001). No differences in adverse effects were recorded, apart from more reoperations to a different target after GPi DBS (GPi n = 8, STN n = 1).

CONCLUSIONS

Off-drug phase motor symptoms and functioning improve more after STN DBS than after GPi DBS. No between-group differences were observed on a composite score for cognition, mood, and behavior, and the inability to participate in follow-up.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that STN DBS provides more off-phase motor improvement than GPi DBS, but with a similar risk for cognitive, mood, and behavioral complications.

Psychiatric and social outcome after deep brain stimulation for advanced Parkinson's disease

BACKGROUND

The aim of this study was to assess psychiatric and social outcome 12 months after bilateral deep brain stimulation (DBS) of the globus pallidus pars interna (GPi) and subthalamic nucleus (STN) for advanced Parkinson's disease (PD).

METHODS

We randomly assigned patients to receive GPi DBS (n = 65) or STN DBS (n = 63). Standardized psychiatric and social questionnaires were assessed at baseline and after 12 months.

RESULTS

No differences were found between GPi DBS and STN DBS on psychiatric evaluation. Within-group comparisons showed small but statistically significant changes on several measures in both groups. Descriptive statistics indicated slight changes in social functioning. Marital satisfaction of patients and partners remained relatively stable after GPi and STN DBS.

CONCLUSIONS

We found neither differences in psychiatric and social outcome between GPi DBS and STN DBS nor any relevant within-group differences. The decision for GPi DBS or STN DBS cannot be based on expected psychiatric or social effects.

Working memory and cognitive flexibility-training for children with an autism spectrum disorder: a randomized controlled trial

BACKGROUND

People with autism spectrum disorders (ASDs) experience executive function (EF) deficits. There is an urgent need for effective interventions, but in spite of the increasing research focus on computerized cognitive training, this has not been studied in ASD. Hence, we investigated two EF training conditions in children with ASD.

METHODS

In a randomized controlled trial, children with ASD (n = 121, 8-12 years, IQ > 80) were randomly assigned to an adaptive working memory (WM) training, an adaptive cognitive flexibility-training, or a non-adaptive control training (mock-training). Braingame Brian, a computerized EF-training with game-elements, was used. Outcome measures (pretraining, post-training, and 6-week-follow-up) were near-transfer to trained EFs, far-transfer to other EFs (sustained attention and inhibition), and parent's ratings of daily life EFs, social behavior, attention deficit hyperactivity disorder (ADHD)-behavior, and quality of life.

RESULTS

Attrition-rate was 26%. Children in all conditions who completed the training improved in WM, cognitive flexibility, attention, and on parent's ratings, but not in inhibition. There were no significant differential intervention effects, although children in the WM condition showed a trend toward improvement on near-transfer WM and ADHD-behavior, and children in the cognitive flexibility condition showed a trend toward improvement on near-transfer flexibility.

CONCLUSION

Although children in the WM condition tended to improve more in WM and ADHD-behavior, the lack of differential improvement on most outcome measures, the absence of a clear effect of the adaptive training compared to the mock-training, and the high attrition rate suggest that the training in its present form is probably not suitable for children with ASD.

Parkinson's disease mild cognitive impairment: application and validation of the criteria

Dementia in Parkinson's disease (PD) is a serious health issue and a major concern for many patients. In most cases mild cognitive impairment (MCI) is considered a transitional stage between normal cognitive functioning and dementia which is of potential importance in the early identification of patients at risk for dementia. Recently, the Movement Disorder Society (MDS) proposed diagnostic criteria for MCI in PD (PD-MCI). These criteria comprise two operationalizations: Level I (based on an abbreviated assessment) and Level II (based on comprehensive neuropsychological evaluation permitting MCI subtyping). These criteria need to be validated. This paper describes a project aiming to validate the MDS PD-MCI criteria by pooling and analyzing cross-sectional and longitudinal neuropsychological databases comprising ≥5,500 PD patients and ≥1,700 controls. After applying the MDS PD-MCI Level I and Level II criteria, rates of conversion to PD-dementia and predictive variables for conversion to PD-dementia will be established. This study will also assist in identifying whether revisions of the PD-MCI criteria are required.

Significance of subjective memory complaints in the clinical setting

OBJECTIVE

The clinical significance of subjective memory complaints in the elderly participants, particularly regarding liability of subsequent progression to dementia, has been controversial. In the present study, we tested the hypothesis that severity or type of subjective memory complaints reported by patients in a clinical setting may predict future conversion to dementia.

METHODS

A cohort of nondemented patients with cognitive complaints, followed up for at least 2 years or until conversion to dementia, underwent a neuropsychological evaluation and detailed assessment of memory difficulties with the Subjective Memory Complaints (SMC) Scale.

RESULTS

At baseline, patients who converted to dementia (36.8%) had less years of formal education and generally a worse performance in the neuropsychological assessment. There were no differences in the total SMC score between nonconverters (9.5 ± 4.2) and converters (8.9 ± 4.0, a nonsignificant difference), but nonconverters scored higher in several items of the scale.

CONCLUSION

For patients with cognitive complaints observed in a memory clinic setting, the severity of subjective memory complaints is not useful to predict future conversion to dementia.

The effect of obstructive sleep apnea and treatment with continuous positive airway pressure on stroke rehabilitation: rationale, design and methods of the TOROS study

Background

Obstructive sleep apnea is a common sleep disorder in stroke patients. Obstructive sleep apnea is associated with stroke severity and poor functional outcome. Continuous positive airway pressure seems to improve functional recovery in stroke rehabilitation. To date, the effect of continuous positive airway pressure on cognitive functioning in stroke patients is not well established. The current study will investigate the effectiveness of continuous positive airway pressure on both cognitive and functional outcomes in stroke patients with obstructive sleep apnea.

Methods/Design

A randomized controlled trial will be conducted on the neurorehabilitation unit of Heliomare, a rehabilitation center in the Netherlands. Seventy stroke patients with obstructive sleep apnea will be randomly allocated to an intervention or control group (n = 2×35). The intervention will consist of four weeks of continuous positive airway pressure treatment. Patients allocated to the control group will receive four weeks of treatment as usual. Outcomes will be assessed at baseline, immediately after the intervention and at two-month follow-up.

In a supplementary study, these 70 patients with obstructive sleep apnea will be compared to 70 stroke patients without obstructive sleep apnea with respect to cognitive and functional status at rehabilitation admission. Additionally, the societal participation of both groups will be assessed at six months and one year after inclusion.

Discussion

This study will provide novel information on the effects of obstructive sleep apnea and its treatment with continuous positive airway pressure on rehabilitation outcomes after stroke.

Trial registration

Trial registration number: Dutch Trial Register NTR3412

Predicting dementia in Parkinson disease by combining neurophysiologic and cognitive markers

OBJECTIVE

To assess the ability of neurophysiologic markers in conjunction with cognitive assessment to improve prediction of progression to dementia in Parkinson disease (PD).

METHODS

Baseline cognitive assessments and magnetoencephalographic recordings from 63 prospectively included PD patients without dementia were analyzed in relation to PD-related dementia (PDD) conversion over a 7-year period. We computed Cox proportional hazard models to assess the risk of converting to dementia conveyed by cognitive and neurophysiologic markers in individual as well as combined risk factor analyses.

RESULTS

Nineteen patients (30.2%) developed dementia. Baseline cognitive performance and neurophysiologic markers each individually predicted conversion to PDD. Of the cognitive test battery, performance on a posterior (pattern recognition memory score < median; hazard ratio (HR) 6.80; p = 0.001) and a fronto-executive (spatial span score < median; HR 4.41; p = 0.006) task most strongly predicted dementia conversion. Of the neurophysiologic markers, beta power < median was the strongest PDD predictor (HR 5.21; p = 0.004), followed by peak frequency < median (HR 3.97; p = 0.016) and theta power > median (HR 2.82; p = 0.037). In combination, baseline cognitive performance and neurophysiologic measures had even stronger predictive value, with the combination of impaired fronto-executive task performance and low beta power being associated with the highest dementia risk (both risk factors vs none: HR 27.3; p < 0.001).

CONCLUSIONS

Combining neurophysiologic markers with cognitive assessment can substantially improve dementia risk profiling in PD, providing potential benefits for clinical care as well as for the future development of therapeutic strategies.

MRI and cerebrospinal fluid biomarkers for predicting progression to Alzheimer's disease in patients with mild cognitive impairment: a diagnostic accuracy study

OBJECTIVES

To assess the incremental value of MRI and cerebrospinal fluid (CSF) analysis after a short memory test for predicting progression to Alzheimer's disease from a pragmatic clinical perspective.

DESIGN

Diagnostic accuracy study in a multicentre prospective cohort study.

SETTING

Alzheimer Disease Neuroimaging Initiative participants with complete data on neuropsychological assessment, MRI of the brain and CSF analysis.

PARTICIPANTS

Patients with mild cognitive impairment (MCI; n=181) were included. Mean follow-up was 38.9 months (range 5.5-75.9).

MAIN OUTCOME MEASURES

Diagnostic accuracy of individual instruments and incremental value of entorhinal cortex volume on MRI and p-τ/Aβ ration in CSF after administration of Rey's Auditory Verbal Learning Memory Test are calculated and expressed as the 'Net Reclassification Improvement' (NRI), which is the change in the percentage of individuals that are correctly diagnosed as Alzheimer or non-Alzheimer case.

RESULTS

Tested in isolation, a short memory test, MRI and CSF all substantially contribute to the differentiation of those MCI patients who remain stable during follow-up from those who progress to develop Alzheimer's disease. The memory test, MRI and CSF improved the diagnostic classification by 21% (95% CI 15.1 to 26.9), 22.1% (95% CI 16.1 to 28.1) and 18.8% (95% CI 13.1 to 24.5), respectively. After administration of a short memory test, however, the NRI of MRI is +1.1% (95% CI 0.1 to 3.9) and of CSF is -2.2% (95% CI -5.6 to -0.6).

CONCLUSIONS

After administration of a brief test of memory, MRI or CSF do not substantially affect diagnostic accuracy for predicting progression to Alzheimer's disease in patients with MCI. The NRI is an intuitive and easy to interpret measure for evaluation of potential added value of new diagnostic instruments in daily clinical practice.

Subthalamic nucleus versus globus pallidus bilateral deep brain stimulation for advanced Parkinson's disease (NSTAPS study): a randomised controlled trial

BACKGROUND

Patients with advanced Parkinson's disease often have rapid swings between mobility and immobility, and many respond unsatisfactorily to adjustments in pharmacological treatment. We assessed whether globus pallidus pars interna (GPi) deep brain stimulation (DBS) gives greater functional improvement than does subthalamic nucleus (STN) DBS.

METHODS

We recruited patients from five centres in the Netherlands who were aged 18 years or older, had idiopathic Parkinson's disease, and had, despite optimum pharmacological treatment, at least one of the following symptoms: severe response fluctuations, dyskinesias, painful dystonias, or bradykinesia. By use of a computer-generated randomisation sequence, we randomly assigned patients to receive either GPi DBS or STN DBS (1:1), applying a minimisation procedure according to drug use (levodopa equivalent dose <1000 mg vs ≥1000 mg) and treatment centre. Patients and study assessors (but not those who assessed adverse events) were masked to treatment allocation. We had two primary outcomes: functional health as measured by the weighted Academic Medical Center Linear Disability Scale (ALDS; weighted by time spent in the off phase and on phase) and a composite score for cognitive, mood, and behavioural effects up to 1 year after surgery. Secondary outcomes were symptom scales, activities of daily living scales, a quality-of-life questionnaire, the occurrence of adverse events, and drug use. We used the intention-to-treat principle for all analyses. This trial is registered with www.controlled-trials.com, number ISRCTN85542074.

FINDINGS

Between Feb 1, 2007, and March 29, 2011, we enrolled 128 patients, assigning 65 to GPi DBS and 63 to STN DBS. We found no statistically significant difference in either of our primary outcomes: mean change in weighted ALDS (3·0 [SD 14·5] in the GPi group vs 7·7 [23·2] in the STN group; p=0·28) and the number of patients with cognitive, mood, and behavioural side-effects (36 [58%] of 62 patients in the GPi group vs 35 [56%] of 63 patients in the STN group; p=0·94). Secondary outcomes showed larger improvements in off-drug phase in the STN group compared with the GPi group in the mean change in unified Parkinson's disease rating scale motor examination scores (20·3 [16·3] vs 11·4 [16·1]; p=0·03), the mean change in ALDS scores (20·3 [27·1] vs 11·8 [18·9]; p=0·04), and medication (mean levodopa equivalent drug reduction: 546 [SD 561] vs 208 [521]; p=0·01). We recorded no difference in the occurrence of adverse events between the two groups. Other secondary endpoints showed no difference between the groups.

INTERPRETATION

Although there was no difference in our primary outcomes, our findings suggest that STN could be the preferred target for DBS in patients with advanced Parkinson's disease.

FUNDING

Stichting Internationaal Parkinson Fonds, Prinses Beatrix Fonds, and Parkinson Vereniging.

Neuropsychological functioning after CPAP treatment in obstructive sleep apnea: a meta-analysis

The generally held clinical view is that treatment with continuous positive airway pressure (CPAP) improves cognition in patients with obstructive sleep apnea (OSA). However, the cognitive domains in which recovery is found differ between studies. A meta-analysis was conducted to quantify the effect of CPAP treatment in OSA on neuropsychological functioning. A literature search of studies published from January 1990 to July 2012 was performed. The inclusion criteria were: randomized controlled trial, diagnosis of OSA by poly(somno)graphy, apnea/hypopnea index, duration and compliance of CPAP treatment reported, use of one or more standardized neuropsychological tests. Mean weighted effect sizes of CPAP treatment for seven cognitive domains were calculated, including processing speed, attention, vigilance, working memory, memory, verbal fluency and visuoconstruction. Thirteen studies encompassing 554 OSA patients were included. A small, significant effect on attention was observed in favor of CPAP (d = 0.19). For the other cognitive domains the effect sizes did not reach significance. Improvement on measures of sleepiness was modest (d = 0.30-0.53) and comparable to prior research. In conclusion, this meta-analysis indicates that the effect of CPAP on cognition is small and limited to attention. Contrary to the general assumption, only slight improvement of neuropsychological functioning after CPAP treatment can be expected.

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

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

Identification of responders and reactive domains to rivastigmine in Alzheimer's disease

PURPOSE

Presently, it is unclear which patients suffering from Alzheimer's Disease (AD) respond to rivastigmine and if rivastigmine acts on specific cognitive domains. The aims of this study are thus to investigate treatment effects of rivastigmine on specific cognitive domains and to find possible responsive subpopulations to rivastigmine cognitive effects.

METHODS

Mini Mental State Examination (MMSE) and Cambridge Cognitive Examination (CAMCOG) were administered at baseline and after 6 months in 83 rivastigmine users and 96 historical controls, representing natural decline. Treatment effects on different subsections of the CAMCOG and in different subpopulations were investigated by linear regression analyses.

RESULTS

Rivastigmine showed effectiveness on total CAMCOG (p < 0.001), CAMCOG non-memory subsection (p < 0.001) and subscales of language (p = 0.002), attention/calculation (p = 0.043), abstract thinking (p < 0.001) and perception (p = 0.031). In patients with baseline MMSE < or =19 rivastigmine showed significant and favourable effects compared to historical controls on total CAMCOG (p < 0.001) and both non-memory (p < 0.001) and memory subsections (p = 0.002).

CONCLUSION

Rivastigmine showed primarily effectiveness on the non-memory section of the CAMCOG and patients with a baseline MMSE < or = 19 appeared to show greater responses to rivastigmine compared to patients with baseline MMSE > or = 20.

Dexamethasone and long-term outcome in adults with bacterial meningitis

OBJECTIVE

This follow-up study of the European Dexamethasone Study was designed to examine the potential harmful effect of adjunctive dexamethasone treatment on long-term neuropsychological outcome in adults with bacterial meningitis.

METHODS

Neurological, audiological, and neuropsychological examinations were performed in adults who survived pneumococcal or meningococcal meningitis.

RESULTS

Eighty-seven of 99 (88%) eligible patients were included in the follow-up study; 46 (53%) were treated with dexamethasone and 41 (47%) with placebo. Median time between meningitis and testing was 99 months. Neuropsychological evaluation showed no significant differences between patients treated with dexamethasone and placebo. The proportions of patients with persisting neurological sequelae or hearing loss were similar in the dexamethasone and placebo groups. The overall rate of cognitive dysfunction did not differ significantly between patients and control subjects; however, patients after pneumococcal meningitis had a higher rate of cognitive dysfunction (21 vs 6%; p = 0.05) and experienced more impairment of everyday functioning due to physical problems (p = 0.05) than those after meningococcal meningitis.

INTERPRETATION

Treatment with adjunctive dexamethasone is not associated with an increased risk for long-term cognitive impairment. Adults who survive pneumococcal meningitis are at significant risk for long-term neuropsychological abnormalities.

Asking the age question in elderly populations: a reverse record check study

In two large-scale surveys among elderly respondents we evaluated the accuracy of answers obtained to three differently formulated age questions. Respondents included 6,149 individuals aged 65-86 living in The Netherlands. Because criterion age data were available from different sources, it was possible to compare the respondent's reported age with his or her actual age. Refusal rates were low for all three questions. Both age and cognitive capabilities influenced accuracy of the answers to the age questions. The results indicated that the most accurate data were obtained with the question, "What is your date of birth?" in combination with interview date.

Effects of adjustment on the case-finding potential of cognitive tests

Adjustment of a cognitive test for an expected level of performance improves the discrimination between brain-diseased and healthy subjects. However, this improvement is subject to severe limitations and may be worthwhile only in clinical settings, where test results tend to be low regardless of disease status. The objective of this study was to provide an empirical demonstration of these principles, applied to the detection of dementia with the Mini-Mental State Examination (MMSE). The subjects, derived from a population-based sample, consisted of 36 cases of dementia (23 diagnosed shortly after testing and 13 at follow-up 1 year later) and 301 nondemented subjects defined by a negative follow-up diagnosis. A simulated group of 179 clinically suspect normals was obtained by selecting all cases with an MMSE score below 27. Adjustment was based on the Dutch version (DART) of the National Adult Reading Test (NART), which was highly correlated (0.53) with the MMSE score of nondemented subjects. The results were in accordance with the predictions. We conclude that adjustment is unlikely to improve case finding in representative samples, but can be profitable in clinical practice, where it will be especially helpful in ruling out cerebral disease.