A feasibility study of smartphone sensors to assess the effect of acute high altitude (3,800 m) exposure on cognition and motor function in healthy participants

Acute exposure to hypoxia at attitude has neurologic effects. Some subjects develop severe neurologic symptoms, including Parkinsonism, when hypoxic at high altitude as part of an Acute Mountain Sickness syndrome. Digital health technologies can provide continuous monitoring and objective, real-world measures of movement disorders, but only limited validation data of wearable sensors is available in the high-altitude setting. This equipment validation and feasibility study assessed smartphone microphone and accelerometer function at sea level and 12470 feet (3,800 m) to assess their potential value to predict and prevent neurologic features of acute mountain sickness. A feasibility study of standardized assessments of motor, speech and cognitive tasks was performed in 3 normal subjects at sea level and at altitude. All subjects were hypoxic at altitude with O2 saturations ranging from 77-81%. Shaker table (range of frequencies) and high-fidelity speaker (range of frequencies) controls confirmed high correlation of observed and expected measurements for microphone and accelerometer under all conditions. The feasibility study demonstrated that under conditions of hypoxia at attitude, fine motor skills are impaired; visual short-term memory is not impaired but has longer response time; gait and balance is impaired, and a postural tremor develops with frequencies below 10 Hz. Future studies could use these wearable sensors to further assess effects at altitude of more severe hypoxia with applications in the high-altitude environment for Parkinsons Disease patients, with further opportunity for aviation and military use.