title: First- and second-order contrast sensitivity functions reveal disrupted visual processing following mild traumatic brain injury.
abstract: Vision is disrupted by traumatic brain injury (TBI), with vision-related complaints being amongst the most common in this population. Based on the neural responses of early visual cortical areas, injury to the visual cortex would be predicted to affect both 1(st) order and 2(nd) order contrast sensitivity functions (CSFs)-the height and/or the cut-off of the CSF are expected to be affected by TBI. Previous studies have reported disruptions only in 2(nd) order contrast sensitivity, but using a narrow range of parameters and divergent methodologies-no study has characterized the effect of TBI on the full CSF for both 1(st) and 2(nd) order stimuli. Such information is needed to properly understand the effect of TBI on contrast perception, which underlies all visual processing. Using a unified framework based on the quick contrast sensitivity function, we measured full CSFs for static and dynamic 1(st) and 2(nd) order stimuli. Our results provide a unique dataset showing alterations in sensitivity for both 1(st) and 2(nd) order visual stimuli. In particular, we show that TBI patients have increased sensitivity for 1(st) order motion stimuli and decreased sensitivity to orientation-defined and contrast-defined 2(nd) order stimuli. In addition, our data suggest that TBI patients' sensitivity for both 1(st) order stimuli and 2(nd) order contrast-defined stimuli is shifted towards higher spatial frequencies.
authors.affiliation: Traumatic Brain Injury Program, The Research Institute of the McGill University Health Center, Montréal, Canada; McGill Vision Research Unit, Department of Ophthalmology, McGill University, Montréal, Canada. Electronic address: daniel.spiegel@mcgill.ca.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Spiegel
authors.affiliation: McGill Vision Research Unit, Department of Ophthalmology, McGill University, Montréal, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Reynaud
authors.affiliation: McGill Vision Research Unit, Department of Ophthalmology, McGill University, Montréal, Canada.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Ruiz
authors.affiliation: Traumatic Brain Injury Program, The Research Institute of the McGill University Health Center, Montréal, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, Canada.
authors.forename: Maude
authors.initials: M
authors.lastname: Laguë-Beauvais
authors.affiliation: McGill Vision Research Unit, Department of Ophthalmology, McGill University, Montréal, Canada.
authors.forename: Robert
authors.initials: R
authors.lastname: Hess
authors.affiliation: Traumatic Brain Injury Program, The Research Institute of the McGill University Health Center, Montréal, Canada; McGill Vision Research Unit, Department of Ophthalmology, McGill University, Montréal, Canada. Electronic address: reza.farivar@mcgill.ca.
authors.forename: Reza
authors.initials: R
authors.lastname: Farivar
mesh_terms: D000293:Adolescent; D000328:Adult; D000070642:Brain Injuries, Traumatic / Q000503:physiopathology*; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009039:Motion Perception / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology; D055815:Young Adult
keywords: Contrast sensitivity; First order vision; Motion perception; Second order vision; Traumatic brain injury