Development and evaluation of a computerized choice reaction time task to assess attentional and memory processes in clinical populations

Abstract

Impairments of attention and memory feature commonly in a broad range of developmental, neurological, and psychiatric conditions. Such impairments can have a profound impact upon daily functioning and upon overall psychosocial adjustment. Assisting those with attentional and memory problems necessitates the availability of reliable and valid assessment tools that yield a comprehensive understanding of the problems and an accurate specification of treatment needs. Traditionally, there have been two main approaches to the assessment of attention and memory: the psychological testing approach, which employs psychometric tests to identify individual differences in constructs such as sustained attention and short-term memory; and the information processing approach, which uses theoretically-based, analytical tasks in order to identify the more elementary cognitive processes that underlie these constructs.Although to date it has not been widely applied in the clinical setting, the information processing approach to assessment has a number of advantages over alternative assessment methods. The approach utilizes computerized reaction time tasks that are convenient to administer, require relatively brief assessment periods, and provide for almost instantaneous data collection, interpretation, and feedback. By analyzing the effects that task variables have upon performance measures, processes that underlie performance can be isolated, measured, and compared. The approach can consequently provide a more detailed analysis of an individual's performance, highlight which aspects of information processing are impaired, and enable rehabilitative efforts to be targeted with greater precision.The present project sought to develop a computerized choice reaction time task based upon on the information processing approach to assessment that would enable simultaneous measurement of five cognitive processes underlying attentional and short-term memory functioning. The task essentially required subjects to memorize sets of words and to then recognize items from the sets after a brief delay period. Four task variables (stimulus quality, memory set size, response set size, and response complexity) were manipulated, and the effects of these variables on decision time and movement time were analyzed, in order to operationalize five processes (stimulus encoding, memory comparison, response selection, motor programming, and response execution). The reliability, validity, and clinical utility of the task as a measure of these processes was then investigated with the goal of rendering it suitable for use in the clinical setting.Chapter 1 of this dissertation reviews relevant literature on approaches to the assessment of attention and memory, with particular emphasis on the information processing approach and its clinical applications to date. Chapter 2 details the development of the computerized choice reaction time task. The results of two experimental studies provided support for the task as a measure of stimulus encoding, memory comparison, and response selection processes. Difficulties were, however, encountered in operationalizing the motor programming process and in establishing response execution as an independent cognitive process. Chapters 3 and 4 describe and evaluate modifications made to the choice reaction time task in order to more effectively operationalize these two processes.n n nChapter 5 presents the results of a preliminary investigation into the reliability and validity of the choice reaction time task as a measure of attentional and short-term memory processes. Analyzes of test-retest reliability indicated that the task was measuring stable constructs. Analyzes of the relationships between indices of information processing derived from the choice reaction time task and those derived from more traditional, psychometric tests of attention and memory provided support for the choice reaction time task as measuring a number of distinct cognitive processes underlying attention and short-term memory.n n