Assessment of vision and visual attention in minimally responsive brain injured patients

Sensory, motor, and cognitive assessment is a critical priority in the care of minimally responsive brain-injured patients. However, their inconsistent pattern of responding may interfere with the use of traditional forms of assessment such as the mental status or neurological examinations. In this article we describe a quantitative method, based on single-subject experimental design, for evaluating vision and visual attention in this patient population. In a series of randomized trials, combinations of a blank card, a colorful photograph, and no stimulus are presented to either or both visual fields while horizontal eye movements are observed. The relationship between the side and nature of the visual stimulus and the frequency of eye movements is analyzed to determine visual function in one or both eyes. We report six cases of minimally responsive patients assessed with this method. In case A, we show evidence of functional vision in both visual fields. Case B also shows functional fields, but with a monocular visual deficit. Cases C and D show a homonymous hemianopsia which, in case D, is further complicated by a monocular visual deficit. Finally, cases E and F show patterns of left and right visual extinction. Thus, this objective and quantitative method leads to conclusions about patients' visual function that are not readily apparent by clinical observation and that allow appropriate modifications in further assessment or treatment.