A hierarchical model for evaluation and treatment of visual perceptual dysfunction in adult acquired brain injury, Part 2.

A framework for evaluation and treatment of visual perceptual dysfunction in adults with acquired brain injury is presented. The framework is based on the concept of a hierarchical structure of perceptual skill levels that interact and subserve one another. Higher level skills in the structure evolve from the integration of lower level skills and are subsequently affected by disruption of the lower level skills. Oculomotor control, the visual fields, and visual acuity form the foundation skills in the framework, followed by visual attention, scanning, pattern recognition, memory, and visual cognition. The order of evaluation and treatment is dictated by the framework. Emphasis is placed on identification and remediation of deficits in the lower level skills that will cause spontaneous improvement of higher level skills. Three treatment principles and five training guidelines are presented that reflect this concept. Specific examples of treatment tasks are provided.