Authors:

PEERS, P., CUSACK, R., Antoun, N., & DUNCAN, J.

Reference:

Year of publication:

2004

CBU number:

5763

Abstract:

Objectives: A computational model of normal visual attention, the Theory of Visual Attention (TVA, Bundesen 1992) was used to examine the profile of attentional abilities in groups of patients frontal and posterior lesioned patients and healthy controls. Methods: Experiments were designed to examine TVA parameters which capture spatial and non-spatial aspects of attention. The parameters studied include: Rate of uptake of visual information, C, derived from identification performance of a single item at multiple exposure durations. Spatial bias, examined using a whole report paradigm with targets presented to the left, right, or both sides, of fixation. Capacity of visual short term memory (VSTM), K, derived from the maximum number of items reported in the whole report experiment. Results: Deficits in all parameters were seen in patients with posterior lesions. Patients with frontal lesions however, only showed impairments in spatial bias . Additionally, it was found that deficits in speed of processing, C, and VSTM capacity, K, were correlated with lesion location in the posterior group, such that damage to the temporal-parietal-junction lead to the largest impairments. Lesion volume was found to be a poor predictor of deficits in C and K. In both frontal and posterior groups, lesion volume, but not location, correlated with the degree of spatial bias. Conclusions: TVA has proved a powerful theory to examine a range of separable attentional functions in this patient population.