Reaction time characteristics after minor head injury: Evidence for slowing, variability, and attentional lapses.
Item
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Title
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Reaction time characteristics after minor head injury: Evidence for slowing, variability, and attentional lapses.
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Identifier
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AAI9218254
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identifier
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9218254
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Creator
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Newman, Bonnie Jill.
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Contributor
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Adviser: Gad Hakerem
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Date
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1992
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Psychobiology | Psychology, Clinical | Psychology, Psychometrics
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Abstract
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Reaction time (RT) speed, intra-individual variability and lapses of attention were explored after minor head injury (MHI) using two methodologies. A conventional discrete trial test and a twelve minute continuous RT were administered whereby subjects were required to respond to a target stimulus when it appeared on the computer screen, and ignore an irrelevant foil stimulus. Two subgroups of MHI patients (labeled as dysfunctional and functional) were identified based on differences in functional impairment post injury (M = 2.5 years), and compared to a group of matched controls. Time on task decrements as a function of fatigue and the effects of varying inter-stimulus interval (ISI) were evaluated on the continuous RT test (CRT).;RT latency scores discriminated between dysfunctional and functional MHI patients on both tests. Dysfunctional patients were slower and more variable in speed than both functional patients and controls. Performance differences between the two MHI subgroups were consistent in direction with differences in number and severity of postconcussional symptoms, emotional symptoms, vocational status, and attentional complaints in every day life. Dysfunctional patients evidenced significantly more response omissions indicative of lapses of attention on the CRT than functional patients. The presence of lapses of attention was pathognomonic to MHI supporting the CRT as a potential screening test.;While all subjects demonstrated increased latency as a function of fatigue and decreases in ISI, dysfunctional patients demonstrated progressively more lapses of attention as a function of time on task (an interaction). The usefulness of the CRT as an assessment tool was strengthened by the finding that a greater number of subjects in all groups were correctly classified by CRT performance criteria than by discrete trial performance criteria. The increase in RT latency for the dysfunctional group could not be solely accounted for by their increased intra-individual variability. Even their fastest RT's were significantly slower than control and functional subjects'. There were no differences between groups in false alarm speed or error rate indicating that MHI subjects were no more impulsive than control subjects, and were equally able to inhibit responding to distracting information.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
