Demonstration of cognitive decline in Parkinson's disease using the Cambridge Cognitive Assessment (Revised) (CAMCOG-R)

Anterior cingulate dopamine turnover and behavior change in Parkinson's disease

Subtle cognitive and behavioral changes are common in early Parkinson's disease. The cause of these symptoms is probably multifactorial but may in part be related to extra-striatal dopamine levels. 6-[(18) F]-Fluoro-L-dopa (FDOPA) positron emission tomography has been widely used to quantify dopamine metabolism in the brain; the most frequently measured kinetic parameter is the tissue uptake rate constant, Ki. However, estimates of dopamine turnover, which also account for the small rate of FDOPA loss from areas of specific trapping, may be more sensitive than Ki for early disease-related changes in dopamine biosynthesis. The purpose of the present study was to compare effective distribution volume ratio (eDVR), a metric for dopamine turnover, to cognitive and behavioral measures in Parkinson's patients. We chose to focus the investigation on anterior cingulate cortex, which shows highest FDOPA uptake within frontal regions and has known roles in executive function. Fifteen non-demented early-stage PD patients were pretreated with carbidopa and tolcapone, a central catechol-O-methyl transferase (COMT) inhibitor, and then underwent extended imaging with FDOPA PET. Anterior cingulate eDVR was compared with composite scores for language, memory, and executive function measured by neuropsychological testing, and behavior change measured using two informant-based questionnaires, the Cambridge Behavioral Inventory and the Behavior Rating Inventory of Executive Function-Adult Version. Lower mean eDVR (thus higher dopamine turnover) in anterior cingulate cortex was related to lower (more impaired) behavior scores. We conclude that subtle changes in anterior cingulate dopamine metabolism may contribute to dysexecutive behaviors in Parkinson's disease.

Screening for Mild Cognitive Impairment in Parkinson's Disease: Comparison of the Italian Versions of Three Neuropsychological Tests

Mild cognitive impairment (MCI) is frequent in Parkinson's disease (PD). Recently proposed criteria for MCI in PD (PD-MCI) indicate level I diagnosis based on abbreviated assessment and level II based on comprehensive neuropsychological evaluation. The study explored the sensitivity and specificity of the Italian versions of three neuropsychological tests for level I diagnosis of PD-MCI. We recruited 100 consecutive PD patients. After screening for inclusion criteria, 43 patients were included. The sensitivity and specificity of the Mini Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), and the Addenbrooke's Cognitive Examination Revised (ACE-R) in comparison to level II diagnosis of PD-MCI were examined. PD-MCI was diagnosed (level II) in 51% of patients. Disease duration was significantly longer and PD motor scales were more severely impaired in MCI group. The receiver-operator characteristics curve documented nonsignificant difference in the performance of the three tests, with slight advantage of MMSE (corrected data). The time of administration favored MMSE. In Italian-speaking PD patients, MMSE might represent a good screening tool for PD-MCI, because of the shorter time of administration and the performance comparable to those of MoCA and ACE-R. Further studies are needed to validate the new PD-MCI criteria across different languages and cultures.

Applications of technology in neuropsychological assessment

Most neuropsychological assessments include at least one measure that is administered, scored, or interpreted by computers or other technologies. Despite supportive findings for these technology-based assessments, there is resistance in the field of neuropsychology to adopt additional measures that incorporate technology components. This literature review addresses the research findings of technology-based neuropsychological assessments, including computer- and virtual reality-based measures of cognitive and functional abilities. We evaluate the strengths and limitations of each approach, and examine the utility of technology-based assessments to obtain supplemental cognitive and behavioral information that may be otherwise undetected by traditional paper-and-pencil measures. We argue that the potential of technology use in neuropsychological assessment has not yet been realized, and continued adoption of new technologies could result in more comprehensive assessment of cognitive dysfunction and in turn, better informed diagnosis and treatments. Recommendations for future research are also provided.

Biomarker candidates of neurodegeneration in Parkinson's disease for the evaluation of disease-modifying therapeutics

Reliable biomarkers that can be used for early diagnosis and tracking disease progression are the cornerstone of the development of disease-modifying treatments for Parkinson’s disease (PD). The German Society of Experimental and Clinical Neurotherapeutics (GESENT) has convened a Working Group to review the current status of proposed biomarkers of neurodegeneration according to the following criteria and to develop a consensus statement on biomarker candidates for evaluation of disease-modifying therapeutics in PD. The criteria proposed are that the biomarker should be linked to fundamental features of PD neuropathology and mechanisms underlying neurodegeneration in PD, should be correlated to disease progression assessed by clinical rating scales, should monitor the actual disease status, should be pre-clinically validated, and confirmed by at least two independent studies conducted by qualified investigators with the results published in peer-reviewed journals. To date, available data have not yet revealed one reliable biomarker to detect early neurodegeneration in PD and to detect and monitor effects of drug candidates on the disease process, but some promising biomarker candidates, such as antibodies against neuromelanin, pathological forms of α-synuclein, DJ-1, and patterns of gene expression, metabolomic and protein profiling exist. Almost all of the biomarker candidates were not investigated in relation to effects of treatment, validated in experimental models of PD and confirmed in independent studies.

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

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

Can the CAMCOG be a good cognitive test for patients with Alzheimer's disease with low levels of education?

BACKGROUND

The Cambridge Cognitive Examination (CAMCOG) is a useful test in screening for Alzheimer's disease (AD). However, the interpretation of CAMCOG cut-off scores is problematic and reference values are needed for different educational strata. Given the importance of earlier diagnoses of mild dementia, new cut-off values are required which take into account patients with low levels of education. This study aims to evaluate whether the CAMCOG can be used as an accurate screening test among AD patients and normal controls with different educational levels.

METHODS

Cross-sectional assessment was undertaken of 113 AD and 208 elderly controls with heterogeneous educational levels (group 1: 1-4 years; group 2: 5-8 years; and group 3: ≥ 9 years) from a geriatric clinic. submitted to a thorough diagnostic evaluation for AD including the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX). Controls had no cognitive or mood complaints. Sensitivity (SE) and specificity (SP) for the CAMCOG in each educational group was assessed with receiver-operator-characteristic (ROC) curves.

RESULTS

CAMCOG mean values were lower when education was reduced in both diagnostic groups (controls - group 1: 87; group 2: 91; group 3: 96; AD - group 1: 63; group 2: 62; group 3: 77). Cut-off scores for the three education groups were 79, 80 and 90, respectively. SE and SP varied among the groups (group 1: 88.1% and 83.5%; group 2: 84.6% and 96%; group 3: 70.8% and 90%).

CONCLUSION

The CAMCOG can be used as a cognitive test for patients with low educational level with good accuracy. Patients with higher education showed lower scores than previously reported.

[Portuguese adaptation of the Cambridge Cognitive Examination-Revised in a public geriatric outpatient clinic]

This paper presents the results of the first four steps (conceptual, item, semantic, and operational equivalences) of cross-cultural adaptation to Portuguese of the Cambridge Cognitive Examination-Revised (CAMCOG-R). The process was based on the theoretical model proposed by Herdman et al., which includes not only the four steps described above, but also measurement and functional equivalences, not evaluated in the current study. A panel of experts evaluated whether all dimensions that comprise the CAMCOG-R were present in Brazilian reality. Two translations and back-translations were performed, in addition to the 'focus group' technique. The Brazilian Portuguese version of the CAMCOG-R (Br-CAMCOG-R) was developed, maintaining the 69 items from the original instrument, with different levels of difficulty. It was then applied to 196 elders, with the test lasting an average of 43 +/- 9.4 minutes, and an average total score of 67 +/- 14.8 points. The Br-CAMCOG-R can be a useful tool for the cognitive evaluation of elders that tested positive during initial screening.

Progression of Parkinson's disease in the clinical phase: potential markers

Neuromodulatory or even neuroprotective therapy could soon be available for Parkinson's disease (PD), raising the question of how we should define and measure disease progression. Reported evidence suggests that several symptoms worsen with disease duration. Bradykinesia, rigidity, and activities of daily living deteriorate faster at the beginning of the disease, and this deterioration is paralleled by a decline in functional presynaptic dopaminergic activity, as shown by imaging techniques. Cognitive, speech, sleep, and gait difficulties might progress linearly in proportion to disease duration. Reduced variability in heart rate, orthostatic dysfunction, and visual hallucinations start to develop at mid-stage disease and are more common in late stages than earlier stages. In this Review, we summarise our current understanding of the progression of PD-associated symptoms and markers and conclude that an effective measurement of progression of PD must adapt to the different stages of the disease. In addition to routine clinical rating scales, new quantitative assessments of motor and non-motor symptoms, which should be more broadly available, reasonably priced, and easy-to-use, are needed.

Measuring impairments in memory and executive function in older people using the Revised Cambridge Cognitive Examination

OBJECTIVES

The Revised Cambridge Cognitive Examination (CAMCOG-R) is a cognitive screen that has been used to discriminate individuals with dementia from cognitively intact older people. It consists of items assessing various cognitive domains, but the construct validity of the cognitive subscores has not been established yet. The authors examine the subscores Memory and Executive Function in relation to extensive neuropsychological testing in a group of older adults with or without cognitive decline.

DESIGN

Observational study.

SETTING

Memory clinic at the department of geriatrics of a university medical center.

PARTICIPANTS

A convenience sample of 36 outpatients diagnosed with cognitive decline and 24 older healthy participants.

MEASUREMENTS

Sensitivity and specificity of the CAMCOG-R Memory subscore and Executive Function subscore were established using extensive neuropsychological assessment of memory (using the Rey-Auditory Verbal Learning Test, Location Learning Test, Visual Association Test, and Story Recall) and executive function (using the Brixton Spatial Anticipation Test, Trail Making Test, and Key Search test) as the gold standard.

RESULTS

For the CAMCOG-R Executive Function subscore, a cutoff point of 16.5 had a good sensitivity (0.82) and adequate specificity (0.73) for discriminating people with and without executive dysfunction. However, the Total Score and Language subscore also differentiated between people with and without executive dysfunction. The CAMCOG-R Memory subscore could not validly distinguish between people with and without memory impairment.

CONCLUSION

The CAMCOG-R subscores Memory and Executive Function have limited validity, and clinicians should be cautious in interpreting these in the absence of other neuropsychological measures or clinical information.

Reliability of the Brazilian version of the Cambridge Cognitive Examination Revised CAMCOG-R

The study' goal was to evaluate the reliability of the Cambridge Cognitive Examination Revised-Brazilian version (Br-CAMCOG-R), a neuropsychological battery measuring the global cognitive function. It was applied on 123 elders and retested at a mean interval of 30.7 days; 60 were evaluated by two raters at the same time. The intraclass coefficient for the set of items and for the subscales varied from 0.93 to 0.98. In the retests the agreement was nearly perfect for the set of items. There was no expressive range in the stability of the instrument for sex, age, schooling, or for the presence of dementia. The Cronbach' alpha of the set of items of the test was high (0.89). The Br-CAMCOG-R has obtained a high level of stability with time, agreement among raters, and optimum internal consistency; it can be useful for epidemiological studies and in specialized clinics to evaluate cognitive functions in elders.

Dementia and functional decline in patients with Parkinson's disease

Functional decline in Parkinson's disease (PD), characterized by reduced ability to carry out activities of daily living, usually results from typical motor impairment and may be aggravated by concomitant cognitive impairment.

Objective

To compare the functional decline in Parkinson's disease between patients with dementia and cognitively preserved patients.

Methods

From an original sample composed of 50 patients with a clinical diagnosis of idiopathic PD seen in a consecutive series, 33 non-depressed patients were selected comprising 13 with dementia and 20 cognitively preserved individuals. All patients enrolled in this study were drawn from a public outpatient clinic, specialized in movement disorders. The clinical stage of PD was determined by the Hoehn & Yahr scale, and the functional capacity was verified using the Unified Parkinson's Disease Rating Scale UPDRS ADL (subscale II: activities of daily living) and the Schwab & England scale. The two last scales measure the functional degree of independence in activities of daily living. The neuropsychological assessment was performed using The Cambridge Examination for Mental Disorders of the Elderly - CAMCOG, Cognitive Section and the Stroop Color Word Test.

Results

As expected, in comparison with cognitively preserved patients, the group with dementia presented significantly lower scores throughout the neuropsychological evaluation. The patients with dementia were found to have a longer period of disease, a more advanced clinical staging according to the Hoehn & Yahr, and greater functional decline according both to the UPDRS ADL and Schwab & England, with statistically significant difference between the groups.

Conclusion

Patients with dementia were at a more advanced clinical stage of Parkinson's disease and evidenced greater functional decline in comparison with patients without dementia.

Validation of the Cognitive Assessment of Later Life Status (CALLS) instrument: a computerized telephonic measure

BACKGROUND

Brief screening tests have been developed to measure cognitive performance and dementia, yet they measure limited cognitive domains and often lack construct validity. Neuropsychological assessments, while comprehensive, are too costly and time-consuming for epidemiological studies. This study's aim was to develop a psychometrically valid telephone administered test of cognitive function in aging.

METHODS

Using a sequential hierarchical strategy, each stage of test development did not proceed until specified criteria were met. The 30 minute Cognitive Assessment of Later Life Status (CALLS) measure and a 2.5 hour in-person neuropsychological assessment were conducted with a randomly selected sample of 211 participants 65 years and older that included equivalent distributions of men and women from ethnically diverse populations.

RESULTS

Overall Cronbach's coefficient alpha for the CALLS test was 0.81. A principal component analysis of the CALLS tests yielded five components. The CALLS total score was significantly correlated with four neuropsychological assessment components. Older age and having a high school education or less was significantly correlated with lower CALLS total scores. Females scored better overall than males. There were no score differences based on race.

CONCLUSION

The CALLS test is a valid measure that provides a unique opportunity to reliably and efficiently study cognitive function in large populations.