Research Reports - Perceptual organization deficits in traumatic brain injury patients
Neuropsychologia. 2015 Nov;78:142-52. doi:
10.1016/j.neuropsychologia.2015.10.008. Epub 2015 Oct 9.
Costa TL(1), Zaninotto AL(2), Benute GG(2), De Lúcia MC(2), Paiva WS(3), Wagemans
J(4), Boggio PS(5).
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.