Pavan Vaswani, an MD-PhD student at the Johns Hopkins University School of Medicine, has just earned the PhD portion of his dual degree by researching eye movements in A-T. In the Laboratory for Computational Motor Control, headed by Reza Shadmehr, PhD, and under the guidance of Thomas Crawford, MD, pediatric neurologist for the A-T Clinical Center, Vaswani compared how healthy people and people with A-T make certain eye movements.
When healthy individuals shift their gaze, they usually do so with only one or two eye movements. People with A-T tend to make several eye movements when shifting their gaze, a symptom called “saccadic hypometria.” Surprisingly, Vaswani discovered that the saccadic hypometria in A-T isn’t an inherent problem caused by A-T but is instead a result of patients trying to compensate for the actual underlying deficit: the increased “noise” in their brains’ oculomotor systems that make eye movements less precise. People with A-T therefore make slower, halting eye movements in order to make fewer mistakes when shifting their gaze.
“This means,” noted Vaswani, “that what we see as ‘problems’ may actually be how kids with A-T are dealing with their underlying defects, and we need to be careful about how we interpret these symptoms and others when we track disease progression and evaluate therapies.”