Reaction time after head injury: fatigue, divided and focused attention, and consistency of performance.

Abstract

SUMMARY Three groups of patients who had suffered head injury were compared with matched control subjects on reaction time (RT) tasks. Group I consisted of outpatients previously hospitalised for head injury ofwide ranging degrees of severity, assessed at varying intervals after injury. Group II was composed of non-hospitalised mildly concussed patients. Group III was made up of head injured patients of varying degrees of severity assessed 7-10 months after initial hospitalisation for their injury. The reaction time tests were graded in difficulty, from a simple RT response to a complex choice RT test. In addition, subjects were compared in their ability to ignore redundant information during one of the choice RT tests. The findings indicate that traumatic brain injury causes slower information processing, deficits in divided attention, an impairment of focused attention, and inconsistency of performance.Reaction time (RT) tests have consistently revealed slowness ofinformation processing, a deficit in divided attention after head injury.' In this study, we addressed four specific issues concerning the effects of head injury on reaction time.The question of fatigue was examined by using the same simple RT test at the beginning and end of experimental sessions to see if head injured patients and normal control subjects changed their performance differently across the session.A second question addressed the nature of the attentional deficit. While "There can be no controversy... about the presence of DADs [divided attention deficit] in head injury",2 there has been less success in identifying a specific impairment in focused attention.< Focused attention is tested by evaluating the ability to ignore distracting stimuli. A selective involvement of frontal lobe areas has been suggested in head injury7"'1 and deficits in focused attention using

Neuropsychological and information processing deficits following mild traumatic brain injury

“…The finding that mild TBI participants showed deficits in selective and sustained attention is consistent with a number of studies that have reported problems with attention (e.g., Gentilini et al, 1985Gentilini et al, , 1989Mclean et al, 1983;Stuss et al, 1989). The poorer verbal memory of the mild TBI group also confirms the findings of previous studies undertaken with mild TBI patients (e.g., Dikmen et al, 1986;Stuss et al, 1985).…”

“…Deficits in selective and sustained attention have also been demonstrated following mild TBI (Bigler & Snyder, 1995;Gentilini et al, 1989;Mclean et al, 1983;Stuss et al, 1989). However, studies of executive functioning have reported inconsistent findings.…”

Randomized controlled trial of modafinil for the treatment of fatigue in postpolio patients

“…The serial reaction time task is negatively affected by fatigue. 8,18 The three reaction time tests used in this study were administered using a computer-based program designed using MEL Professional version 2.0 software (Psychology Software Tools, Inc., Pittsburgh, Pennsylvania). For the simple reaction time test, the subject was instructed to strike a key as quickly as possible when a particular number appeared on the screen.…”

Effectiveness of attention rehabilitation after an acquired brain injury: A meta-analysis.

“…The following additional categories were formed to accommodate the other tests of attention: (a) working memory, which shares important similarities with attention (Baddeley, 1993b; Digit Span backwards from the WAIS-R and Paced Auditory Serial Addition Test [PASAT; Gronwall, 1977]); (b) Picture Completion (WAIS-R subtest), which may assess attention to visual detail (Gray et al, 1992); (c) Mental Control (Wechsler Memory ScaleRevised subtest;Wechsler, 1987); (d) simple reaction time (RT); (e) choice RT, which may measure aspects of attention (e.g., Stuss et al, 1989;Van Zomeren & Brouwer, 1994; but also see Ponsford & Kinsella, 1992); and (f) other, which included infrequently used measures (e.g., divided attention and time estimation). A few direct-retraining studies also measured participant-reported mood with depression or anxiety inventories, as well as subjective ratings of attention on a particular task by participants, other observers, or both.…”