Peak Agricultural Pesticide Spray Periods are related to Real-World Cognition Using an Ecological Momentary Assessment Burst Design over Two Years

Objective: Emerging evidence suggests that exposure to organophosphate, neonicotinoid, and other pesticides may transiently impair cognition; however, traditional "snapshot" laboratory-based cognitive assessments fail to capture fluctuations in cognitive performance. This study used ecological momentary cognitive testing (EMCT) to evaluate whether real-world cognitive performance differs between peak and low floricultural pesticide spray seasons, thereby evaluating the potential cyclical effects of agricultural production and related pesticide exposures. Material and Methods: From 2022 to 2024, 15,063 EMCT assessments were completed by 494 participants (ages 17 to 25; 50% female) enrolled in the ESPINA cohort study in Ecuador. Participants completed nine 10-day burst assessments every 2 to 3 months during high and low pesticide spray seasons. EMCTs (NeuroUx) assessed processing speed, executive function, and visual working memory. Mixed-effects models examined associations of peak versus off-peak pesticide spray seasons, floricultural work or occupation (vs not) with EMCT performance, adjusting for socio-economic and other variables, and including participant- and burst-level random intercepts. Results: Peak pesticide spray season, compared to off-peak, was associated with higher T-scores on processing speed tests, including Matching Pair (B= 0.62) and Odd One Out (B= 0.88), but showed no significant association with other tests or the overall cognitive composite. Conversely, direct floricultural employment was significantly associated with lower cognitive performance overall (B= -0.59), with the largest differences observed in Memory Matrix (B= -0.78) and Matching Pair (B= -0.70). Conclusion: Peak pesticide spray seasons were associated with modestly higher processing speed scores, consistent with prior findings in this population suggestive of enhanced cognitive performance associated with neonicotinoid and sulfoximine exposures. In contrast, floricultural employment was associated with significantly lower memory and overall cognitive performance. These results suggest that occupational and seasonal pesticide exposure may have distinct associations with cognitive functioning, highlighting the importance of repeated cognitive testing for characterizing potentially transient effects.