Besides changes due to diurnal rhythms, a wide range of external and internal events can affect, the operation of these cognitive functions, including anxiety,

fatigue, aging, trauma, disease, psychiatric illness, drugs, hormones, cardiac function, and of course, dementia. Cognitive MEK inhibitor drugs function is assessed by requiring subjects (volunteers or patients) to perform specific tasks. The quality of measurement, depends on how well the performance of the tasks can be assessed. This is a very important, issue, as the process of precisely estimating Inhibitors,research,lifescience,medical an individual’s level of cognitive competence is affected by a number of sources of error variance. Clearly, when measuring performance, we are hoping to obtain a reliable and precise estimate of an individual’s cognitive competence. There Inhibitors,research,lifescience,medical are

two principal applications of cognitive function tests in clinical practice and research. The first is to identify the ability to conduct the tasks in order to make an assessment, of the cognitive capabilities of the particular individual. An obvious example in the context of this article would be to determine the presence and, possibly, degree of dementia. The second is to assess change in cognitive function, ie, to assess a person more than once in order to determine whether Inhibitors,research,lifescience,medical the quality of function has altered during the time between the assessments. The latter application is crucial in trials of dementia therapies in which the desire is to determine whether cognitive function has been affected by the therapy. Individuals vary widely Inhibitors,research,lifescience,medical in the quality of their various mental skills and simply assessing them after treatment provides little insight into the nature or extent of any changes. The key to such work is to assess the abilities of the individual prior to treatment and then determine the extent to which these have changed in subsequent assessments. However, repeating

cognitive testing in this manner places very stringent constraints on the design and types of tests that can be used. Inhibitors,research,lifescience,medical These constraints are not present in many other fields, for example, the repeated assessment of biométrie measures such as blood pressure or body weight. With psychometric assessments, which include cognitive tests, performance can change with repeated testing for a variety of reasons that are independent of the study treatment. Examples of these are as follows. Learning many specific items in memory tests. Developing strategies to improve performance. Becoming less anxious. Improving cognitive skills via training effects. Better understanding of the task requirements. Test developers seek to overcome such effects by developing parallel forms of the tests, for example, having different sets of items to be learned in memory tests, or unpredictable sequences of events in tests of attention.