Cognition Test Battery Survey: Development of a Single Alertness and Mood Score for Short- and Long-Duration Spaceflight

Astronaut behavioral and mental health are key factors for space mission success. NASA's Cognition test battery is often preceded by a brief 18-item Alertness and Mood Survey (AMS) adding subjective assessments to Cognition's 10 objective neuropsychological tests. Therefore, the main objective of this study was to generate a single AMS summary score for short (<6 months) and long (>6 months) space missions based on the relevance of individual items. With the paired comparison (PC) method, 19 subject matter experts (SMEs) were asked to rate the relevance of 14 AMS items for astronaut behavioral health. Boredom (22.1% of comparisons), monotony (23.1%), and sleepiness (35.6%) were considered the least relevant, and health (74.3%), depression (76.5%), and crew conflicts (77.9%) were considered the most relevant by SMEs. Six of the fourteen items differed statistically significantly between PCs for short- and long-duration missions: sleepiness, tiredness, energy level, and mental status were considered more relevant for short-duration missions, while monotony and loneliness were considered more relevant for long-duration missions (all adjusted p < 0.05). We also demonstrated systematic changes in AMS summary scores during a 60-day 6 degrees head-down tilt bed rest (HDBR) study, with increased alertness and mood disturbance during and after the HDBR period relative to pre-HDBR levels. This analysis identified the AMS domains considered most relevant for space mission success by SMEs, and highlighted differences between long- and short-duration missions. The resulting AMS summary scores were based on item relevance and will be useful for monitoring astronaut behavioral health on short- and long-duration space missions.