Pointing movement in short and long-term exposure to hypoxia

Kinematics variables of pointing movements where assessed in five adult subjects exposed acutely (30 min) and chronically (10 days) to a low O2 mixture (13.5% O2 in N2). Amplitude of displacement did not vary in both experimental conditions but movement duration markedly increased compared to pre and post exposure conditions. While in acute hypoxia the times of acceleration and deceleration are almost equal, in chronic hypoxia deceleration time exceeded of 100 ms the time of acceleration. The time from the peak acceleration to the peak of deceleration ("switch" time) increased in both experimental conditions and was about 50% of the movement duration. This time lengthening at hypoxia may be explained either by alteration of propioceptive loops or by a different strategy elaborated by the CNS to generally slow accurate movements.