title: First- and Second-Order Stimuli Reaction Time Measures Are Highly Sensitive to Mild Traumatic Brain Injuries.
abstract: Mild traumatic brain injury (mTBI) has subtle effects on several brain functions that can be difficult to assess and follow up. We investigated the impact of mTBI on the perception of sine-wave gratings defined by first- and second-order characteristics. Fifteen adults diagnosed with mTBI were assessed at 15 days, 3 months, and 12 months postinjury. Fifteen matched controls followed the same testing schedule. Reaction times (RTs) for flicker detection and motion direction discrimination were measured. Stimulus contrast of first- and second-order patterns was equated to control for visibility, and correct-response RT means, standard deviations (SDs), medians, and interquartile ranges (IQRs) were calculated. The level of symptoms was also evaluated to compare it to RT data. In general in mTBI, RTs were longer, and SDs as well as IQRs larger, than those of controls. In addition, mTBI participants' RTs to first-order stimuli were shorter than those to second-order stimuli, and SDs as well as IQRs larger for first- than for second-order stimuli in the motion condition. All these observations were made over the three sessions. The level of symptoms observed in mTBI was higher than that of control participants, and this difference did also persist up to 1 year after the brain injury, despite an improvement. The combination of RT measures with particular stimulus properties is a highly sensitive method for measuring mTBI-induced visuomotor anomalies and provides a fine probe of the underlying mechanisms when the brain is exposed to mild trauma.
authors.affiliation: 1 Visual Psychophysics and Perception Laboratory, École d'Optométrie, Université de Montréal , Montréal, QC, Canada .
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Piponnier
authors.affiliation: 2 École de réadaptation, Université de Montréal , and Centre de recherche interdisciplinaire en réadaptation du Montréal métropolitain, Montréal, QC, Canada .
authors.forename: Robert
authors.initials: R
authors.lastname: Forget
authors.affiliation: 3 Montreal Children's Hospital, McGill University Health Center, and School of Physical and Occupational Therapy, McGill University , Montreal, Montréal, QC, Canada .
authors.forename: Isabelle
authors.initials: I
authors.lastname: Gagnon
authors.affiliation: 4 Centre de recherche interdisciplinaire en réadaptation-Centre de réadaptation Lucie-Bruneau, and Département de psychologie, Université de Montréal , Montréal, QC, Canada .
authors.forename: Michelle
authors.initials: M
authors.lastname: McKerral
authors.affiliation: 5 Department of Surgery, Sacré-Coeur Hospital affiliated with Université de Montréal , Montréal, QC, Canada .
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Giguère
authors.affiliation: 1 Visual Psychophysics and Perception Laboratory, École d'Optométrie, Université de Montréal , Montréal, QC, Canada .
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Faubert
mesh_terms: D000293:Adolescent; D000328:Adult; D001930:Brain Injuries / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: first-order; mTBI; motion; reaction time; second-order