Assessing Change in Cognitive Function in Dementia: The Relative Utilities of the Alzheimer’s Disease Assessment Scale – Cognitive Subscale and the Cognitive Drug Research System
Cognitive Drug Research Ltd., Goring-on-Thames, UK. Neurodegenerative Diseases
(Impact Factor: 3.51).
02/2008; 5(3-4):261-3. DOI: 10.1159/000113719
This paper considers the suitability of the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog) as the gold standard in registration trials of treatments for Alzheimer's disease. Working groups have recommended replacing the ADAS-cog if suitable automated alternatives can be found. This paper makes the case for the Cognitive Drug Research (CDR) computerised cognitive assessment system, as an example of a suitable instrument to replace the ADAS-cog. The CDR system has been widely used in dementia work for 20 years and shows good correlations to the ADAS-cog, while additionally assessing the domains of attention, working memory, information processing and retrieval speed of information held in memory. The utility of the system in evaluating and differentiating the major dementias will be described, as well as its ability to track deterioration over time. Its validation as a core measure of cognitive dysfunction in the dementias will be described, as will work showing that various CDR measures relate closely to activities of daily living. The sensitivity of the CDR system to anticholinesterases will be described in Alzheimer's disease, dementia with Lewy bodies and Parkinson's dementia. Finally, the CDR system has a large normative database which allows treatment effects in dementia to be put into an unambiguous clinical perspective.
Available from: Josephine N Booth
- "which had the digit vigilance targets detected, digit vigilance false alarms and choice reaction time accuracy loaded on it. These factors have previously been identified for the CDR system (Wesnes, 2008; Wesnes, Ward, McGinty, & Petrini, 2000) and factor scores were employed for all further analysis. Associations between PA (all variables adjusted for wear time) and attention tasks were assessed using multiple linear regression. "
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ABSTRACT: Studies of relationships between physical activity and children's attention skills are often constrained by small samples, lack of objective measurements and lack of control for confounders. The present study explores the relationship using objective measures of physical activity from a large birth cohort which permits both longitudinal and cross-sectional analyses. Data from 4755 participants (45% male) with valid measurement of physical activity (total volume and intensity) by accelerometry at age 11 from the Avon Longitudinal Study of Parents and Children (UK) were analysed. Attention was evaluated by the Test of Everyday Attention for Children (TEA-Ch) at 11 years and by the Cognitive Drug Research (CDR) computerised cognitive assessment system at 13 years. Males engaged in an average of 29 min (SD 17) of daily moderate-to-vigorous physical activity (MVPA) at age 11 years compared with 18 min (SD 12) among females. In unadjusted models, higher total volume of physical activity was associated with lower performance across attention tasks. When total volume of physical activity and potential confounding variables were controlled for, higher MVPA was associated with better performance at both 11 and 13 years. Correction for regression dilution approximately doubled the standardised β coefficients. We observed complex associations but results suggest that MVPA may be beneficial for attention processes in adolescence, especially in males. This has implications for interventions aimed at improving executive attention but may also be supportive of the benefits of physical activity for educational and mental health outcomes.
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ABSTRACT: Alzheimer's disease (AD) is a devastating degenerative disorder for which there is no cure or effective treatment. In the
late stages of the disease when there is evident cognitive impairment, the clinical diagnosis of probable AD is made with
around 90% accuracy using clinical, neuropsychological, and imaging methods. Diagnostic sensitivity and specificity in early
disease stages are improved by cerebrospinal fluid markers, for example, combined tau and amyloid-β (Aβ) peptides and some
plasma markers. At this time, however, validated diagnostic markers for early diagnosis of AD are not available. Simple, accurate,
and noninvasive tests for an early detection of AD are urgently required to attempt intervention before substantial and irreversible
brain damage occurs. Compelling evidence indicates that deposition of aggregates composed by a misfolded form of Aβ is the
central event in the disease pathogenesis. Therefore, an attractive diagnostic strategy is to detect the misfolded form of
Aβ in biological fluids. In this chapter, we describe current diagnosis methods, their principles, and their potential strengths
and weaknesses. Overall, the available data suggests the feasibility in developing a sensitive diagnostic test for the early
detection of AD.
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ABSTRACT: Decreased speed of information processing is a hallmark of Alzheimer's disease (AD) and mild cognitive impairment (MCI). Recent studies suggest that response speed (RS) measures are very sensitive indicators of changes in longitudinal follow-up studies. Insight into the psycho-physiological underpinnings of slowed RS can be provided by measuring the associated event-related potentials (ERP).
The current study aims to investigate the relation between RS and its psycho-physiological correlates in AD and MCI.
Fifteen psychoactive drug-naïve AD patients, 20 MCI patients and twenty age-matched, healthy control subjects participated. Response speed was measured during a simple (SRT) and choice reaction time task (CRT). An oddball and contingent negative variation (CNV) paradigm were used to elicit ERP. To evaluate test-retest reliability (TRR), subjects underwent a similar assessment one week after the first.
The SRT and CRT distinguished the patient groups significantly. The P300 amplitude and latency also distinguished the groups and showed a significant correlation with response speed. The CNV amplitude did not reveal a significant difference between groups and also showed a low TRR. The TRR of the SRT, CRT and P300 amplitude and latency in general was moderate to high. The current study suggests that response speed measures on a behavioural and psycho-physiological level deserve attention as a possible marker in the diagnosis and follow-up of AD.
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