Standardised Analysis of Visual-spatial Perception after Brain Damage

Abstract

Disorders of visual space perception and cognition are frequent in patients with brain damage. In this paper we describe further developments of a new PC-based system (termed VS) that allows the quantitative assessment of a variety of visual-spatial abilities (Subjective Visual Axes, Visual Orientation Discrimination, Length, Distance, Form and Position Discrimination, and Line and Distance Bisection). Besides other features, VS offers various useful properties, i.e. the automatic computation of psychophysical parameters (method of limits), the experimental manipulation of task parameters, the definition of macro files, and the configuration of high quality graphic laser printouts. The basic features of this system have already been described in a preceding paper (Kerkhoff & Marquardt, 1995). In the present paper we describe five useful clinical standard examinations together with preliminary normative data and present graphic printouts of the results developed with this system. These standard examinations include a short (5 subtests) and a long screening examination (11 tests), a test of the Subjective Axes and of Form Discrimination (“Efron Shapes”). Furthermore, an investigation of cueing effects in horizontal and vertical Line Bisection is described. Finally, special options such as bedside tests and repeated testing to evaluate changes in performance over time are illustrated. We show in a sample of 20 brain-damaged patients that there are no significant retest effects within a period of 1-3 weeks when twice tested with the same investigation in VS. These standard examinations are easy to implement in clinical practice and can be performed within 10-40 minutes depending on the type of investigation. In summary, the clinical and experimental features of VS may be of clinical utility and may progress the knowledge about visuospatial functions in brain-damaged patients.