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Deary-Liewald Reaction Time Task
Please visit this website for more information about the instrument:
The Deary-Liewald Reaction Time Task programme is available for download from the Centre for Cognitive Ageing and Cognitive Epidemiology (CCACE) software repository website or by emailing Ian J. Deary, or David Liewald,
Exploratory: Myalgic encephalomyelitis/Chronic fatigue syndrome (ME/CFS)
Short Description of Instrument
The Deary-Liewald reaction time task is a computer-based measure of reaction time and information processing speed. It takes 10 minutes to administer. The age range for this task is 18–80 years of age.
There are two parts to the Deary-Liewald, simple reaction time (SRT) and choice reation time (CRT). The CRT is a four-choice task.
Instructions for the task are provided on the website and are also included in the Supplemental Materials in Deary et al., 2011.
Scoring is provided by the programme software which records: response times, inter-stimulus interval, the key pressed, correct/incorrect response for choice task, as well as statistics for the response times (mean, median, variance, standard deviation, skewness, and kurtosis).
ME/CFS Specific:
Advantages: Brief and relatively simple task.
Limitations: Only measures visual attention and response is dependent on keyboard use.
Deary IJ, Liewald D, Nissan J. A free, easy-to-use, computer-based simple and four-choice reaction time programme: the Deary-Liewald reaction time task. Behav Res Methods. 2011;43(1):258-268.
Cockshell SJ, Mathias JL. Cognitive functioning in chronic fatigue syndrome: a meta-analysis. Psychol Med. 2010;40(8):1253-1267.


Document last updated July 2019
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