The Translational Session of the TCMC Satellite — Part 2#SfN14

One of the hallmarks of the movement disorder ataxia telangiectasia (A-T) is that patients have “saccadic hypometria”, or short saccades. Saccades are the only form of voluntary eye movements, involving rapid shift of the target of the eye from one point to another. In A-T, patients tend to fall short of their visual targets during voluntary eye movements, requiring up to 5 saccades to accomplish a shift of gaze where people without saccadic hypometria would require just one or two saccades.

In the study described in the fourth talk of the morning of TCMC, the authors questioned whether saccadic hypometria was truly a primary symptom of A-T. Maybe it is a compensatory solution to a different primary symptom?

The authors of the study went through the kinematics of eye movements in both controls and A-T patients, and found that they were rather comparable. However, the spread of endpoint positions is much higher in A-T patients. Since there is higher variability in their endpoints, the solution for minimizing error in final endpoint would be to increase the number of saccades.

If the increase in the number of saccades is truly a solution for higher endpoint variability, would this show up in other disorders? Could we use this information for rehab purposes?