title: Enhancing the sensitivity of a sustained attention task to frontal damage: convergent clinical and functional imaging evidence.
abstract: Despite frequent reports of poor concentration following traumatic brain injury, studies have generally failed to find disproportionate time-on-task decrements using vigilance measures in this patient group. Using a rather different definition, neuropsychological and functional imaging research has however linked sustained attention performance to right prefrontal function--a region likely to be compromised by such injuries. These studies have emphasised more transitory lapses of attention during dull and ostensibly unchallenging activities. Here, an existing attention measure was modified to reduce its apparent difficulty or 'challenge'. Compared with the standard task, its capacity to discriminate traumatically head-injured participants from a control group was significantly enhanced. Unlike existing functional imaging studies, that have compared a sustained attention task with a no-task control, in study 2 we used positron emission tomography to contrast the two levels of the same task. Significantly increased blood flow in the dorsolateral region of the right prefrontal cortex was associated with the low challenge condition. While the results are discussed in terms of a frontal system involved in the voluntary maintenance of performance under conditions of low stimulation, alternative accounts in terms of strategy application are considered.
authors.affiliation: MRC Cognition and Brain Sciences Unit, Addenbrooke's Hospital, Cambridge, UK. tom.manly@mrc-cbu.cam.ac.uk
authors.forename: Tom
authors.initials: T
authors.lastname: Manly
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Owen
authors.forename: Laura
authors.initials: L
authors.lastname: McAvinue
authors.forename: Avijit
authors.initials: A
authors.lastname: Datta
authors.forename: Geraint H
authors.initials: GH
authors.lastname: Lewis
authors.forename: Sophie K
authors.initials: SK
authors.lastname: Scott
authors.forename: Chris
authors.initials: C
authors.lastname: Rorden
authors.forename: John
authors.initials: J
authors.lastname: Pickard
authors.forename: Ian H
authors.initials: IH
authors.lastname: Robertson
mesh_terms: D000328:Adult; D001288:Attention; D003072:Cognition Disorders / Q000209:etiology* / Q000473:pathology; D006259:Craniocerebral Trauma / Q000150:complications* / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000098:blood supply* / Q000473:pathology / Q000502:physiology; D011930:Reaction Time; D012039:Regional Blood Flow; D013647:Task Performance and Analysis; D014055:Tomography, Emission-Computed