Arterial oxygen desaturation during moderate hypoxia hinders sensorimotor performance

Introduction Moderate hypoxia may impact cognitive and sensorimotor performance prior to self-recognized impairments. Therefore, rapid and objective assessment tools to identify people at risk of impaired function during moderate hypoxia is needed. Purpose Test the hypothesis that reductions in arterial oxygen saturation during moderate normobaric hypoxia (F_iO₂ = 14%) decreases gamified sensorimotor performance as measured by alterations of motor acuity. Methods Following three consecutive days of practice, thirty healthy adults (25 ± 5 y, 10 females) completed three bouts of the tablet-based gamified assessment (Statespace Labs, Inc.) of motor acuity at Baseline and 60 and 90 min after exposure to 13.8 ± 0.2% (hypoxia) and 20.1 ± 0.4% (normoxia) oxygen. The gamified assessment involved moving the tablet to aim and shoot at targets. Both conditions were completed on the same day and were administered in a single-blind, block randomized manner. Performance metrics included shot time and shot variability. Arterial oxyhemoglobin saturation estimated via forehead pulse oximetry (S_pO₂). Data were analyzed using linear mixed effects models. Results Compared to normoxia (99±1%), S_pO₂ was lower (p<0.001) at 60 (89±3%) and 90 (90±2%) min of hypoxia. Shot time was unaffected by decreases in S_pO₂ (0.012, p = 0.19). Nor was shot time affected by the interaction between S_pO₂ decrease and baseline performance (0.006, p = 0.46). Shot variability was greater (i.e., less precision, worse performance) with decreases in S_pO₂ (0.023, p = 0.02) and depended on the interaction between S_pO₂ decrease and baseline performance (0.029, p< 0.01). Conclusion Decreases in SpO₂ during moderate hypoxic exposure hinders sensorimotor performance via decreased motor acuity, i.e., greater variability (less precision) with no change in speed with differing decreases in S_pO₂. Thus, personnel who are exposed to moderate hypoxia and have greater decreases in S_pO₂ exhibit lower motor acuity, i.e., less precise movements even though decision time and movement speed are unaffected.