title: Perceptual organization deficits in traumatic brain injury patients.
abstract: Traumatic brain injury (TBI) is a prevalent condition and there is limited visual perception research with this population. Here, we investigated perceptual organization changes in a rather homogeneous sample of closed head TBI outpatients with diffuse axonal injury only and no other known comorbidities. Patients had normal or corrected visual acuity. Perceptual organization was measured with the Leuven Perceptual Organization Screening Test (L-POST), a coherent motion task (CM) and the Leuven Embedded Figures Test (L-EFT). These tests were chosen to screen for deficits in different aspects of perceptual organization (L-POST), to evaluate local and global processing (L-EFT) and grouping in a dynamic set of stimuli (CM). TBI patients were significantly impaired compared to controls in all measures for both response time and accuracy, except for CM thresholds and object recognition subtests. The TBI group was similarly affected in all aspects of the L-EFT. TBI was also similarly affected in all perceptual factors of the L-POST. No significant correlations were found between scores and time post-injury, except for CM thresholds (rs=-0.74), which might explain the lack of group-level differences. The only score significantly correlated to IQ was L-EFT response time (rs=-0.67). These findings demonstrate that perceptual organization is diffusely affected in TBI and this effect has no substantial correlations with IQ. As many of the neuropsychological tests used to measure different cognitive functions involve some level of visual discrimination and perceptual organization demands, these results must be taken into account in the general neuropsychological evaluation of TBI patients.
authors.affiliation: Social and Cognitive Neuroscience Laboratory and Developmental Disorders Program, Mackenzie Presbyterian University, São Paulo, Brazil; Division of Psychology, Hospital das Clínicas, University of São Paulo Medical School, São Paulo, Brazil. Electronic address: e.thiagocosta@gmail.com.
authors.forename: Thiago L
authors.initials: TL
authors.lastname: Costa
authors.affiliation: Division of Psychology, Hospital das Clínicas, University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Ana Luiza C
authors.initials: AL
authors.lastname: Zaninotto
authors.affiliation: Division of Psychology, Hospital das Clínicas, University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Gláucia G
authors.initials: GG
authors.lastname: Benute
authors.affiliation: Division of Psychology, Hospital das Clínicas, University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Mara C S
authors.initials: MC
authors.lastname: De Lúcia
authors.affiliation: Division of Neurosurgery, University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Wellingson S
authors.initials: WS
authors.lastname: Paiva
authors.affiliation: Department of Brain and Cognition, Laboratory of Experimental Psychology, University of Leuven, Belgium.
authors.forename: Johan
authors.initials: J
authors.lastname: Wagemans
authors.affiliation: Social and Cognitive Neuroscience Laboratory and Developmental Disorders Program, Mackenzie Presbyterian University, São Paulo, Brazil.
authors.forename: Paulo S
authors.initials: PS
authors.lastname: Boggio
mesh_terms: D000293:Adolescent; D000328:Adult; D001930:Brain Injuries / Q000150:complications* / Q000473:pathology / Q000503:physiopathology / Q000523:psychology*; D016022:Case-Control Studies; D016489:Head Injuries, Closed / Q000150:complications / Q000473:pathology / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D007360:Intelligence; D007361:Intelligence Tests; D009039:Motion Perception; D009483:Neuropsychological Tests; D010468:Perceptual Disorders / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D011930:Reaction Time; D021641:Recognition, Psychology; D012720:Severity of Illness Index; D013997:Time Factors; D055815:Young Adult
keywords: Coherent motion; Diffuse axonal injury; Embedded figures; L-POST; Perceptual organization; Traumatic brain injury