1. A method for obtaining eye-fixation duration data or eye-fixation duration and location data for assessing a patient's linguistic comprehension using an eyetracking system comprising at least one video camera and at least one computer that is configured to measure and record the patient's eye-fixation data, the method comprising: a. presenting the patient with a verbal stimulus; b. presenting the patient with a visual stimulus comprising a plurality of images wherein one of the images is a target image that corresponds to the verbal stimulus; c. measuring and recording eye-fixation duration data during steps a and b, wherein an eye fixation is a relatively stable position of the eye for a minimum duration of at least about 40 milliseconds with some slight tolerance in the vertical and horizontal dimensions; and d. analyzing the eye-fixation duration data to assess the patient's linguistic comprehension.