Eye movements in a small sample of cerebral palsied adults

Monocular pursuit and saccadic eye movements were compared between a group of 5 men with cerebral palsy and a group of 5 men with normal movements using an infrared corneal reflection technique. Triangle, sine, and square waves (in the time domain) at 0.3 Hz in the horizontal and vertical dimensions were used as the stimuli for six 10-sec. tests of each subject. The momentary difference between stimulus and eye positions was used to obtain values for five pursuit variables (triangle and sine wave tests) Land five saccadic variables (square wave tests). The t tests for differences between these means showed that the cerebral palsy group had more fixations during the four pursuit tests, more saccadic intrusions during the horizontal pursuit tests, a greater maximum pursuit error during the horizontal sine wave test, and a greater maximum fixation error during the horizontal square wave test. The group means were not different for pursuit gain and saccadic velocity and latency. The dynamics of the errors during the tests of pursuit movements indicate that cerebral palsied persons may be unable to maintain the constant velocity of eye movement required to track a triangle wave stimulus. The dynamics of the errors during the tests of saccadic movements indicate that cerebral palsied persons would be unable to use technological devices for assisting communication, which depend on visual fixation as a control signal.