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.
"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. "
[Show abstract][Hide abstract] 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.
Mental Health and Physical Activity 10/2013; 6(3). DOI:10.1016/j.mhpa.2013.09.002
[Show abstract][Hide abstract] 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.
Brain and Cognition 02/2009; 69(3):592-9. DOI:10.1016/j.bandc.2008.12.007 · 2.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The incidence and prevalence in those over age 65 of neurodegenerative disorders and chronic diseases, which often have deleterious effects on cognition, are rapidly increasing in western societies. Primary care physicians (PCPs) provide the majority of medical treatment for older people and in order to effectively care for their patients with suspected cognitive impairment, they must have tools that will allow them to accurately assess their patient's cognitive function. This knowledge will assist the PCPs in formulating a diagnosis of dementia or cognitive impairment and provide an indication of risk of progression to dementia. It will also assist with monitoring response to treatment and care decisions, including medication management, capacity judgments, and the need for family involvement. Tests currently used in primary care, such as the Mini-Mental State Examination, do not accurately assess patients with mild cognitive impairments, and other tests more suitable for this purpose require further validation and may be too time-consuming in the primary care setting. A possible solution is the use of patient-administered computerized cognitive testing in the PCP's office. This systematic review identified eleven test batteries and three were judged potentially appropriate for cognitive assessment in the PCP's office. These three varied in their presentation format and the quality of cross-sectional validation studies, and none had longitudinal data for dementia prediction. Thus the existing test batteries show potential for use in primary care but further study is needed to demonstrate their feasibility and effectiveness in this setting.
Christine Thai, Yen Ying Lim, Victor L Villemagne, Simon M Laws, David Ames, Kathryn A Ellis, Stephanie R Rainey-Smith, Ralph N Martins, Colin L Masters, Christopher C Rowe, Paul Maruff
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