Cognitive function following reported exposure to contaminated air on commercial aircraft: methodological considerations for future researchers

Abstract

Cabin air on commercial aircraft is sometimes contaminated with jet engine oils containing organophosphates (OP). Aircrew have complained of chronic ill health and cognitive impairment following exposure to contaminated air, but a debate is ongoing about causation, diagnosis and treatment of long-term effects. The incidence of contaminated air events is difficult to quantify, as commercial aircraft do not have air quality monitoring systems on board. According to statistical records, certain types of aircraft suffer more fume events than others (e.g. the BAe 146 and Boeing 757) and it has been suggested that airframe may serve as a proxy measure of exposure. The current study sought to investigate this claim, and to determine whether an association exists between exposure to contaminated air and neuropsychological impairment. Twenty-nine pilots were recruited and split into two exposure groups according to aircraft type flown, but few differences were noted between groups in terms of exposure history or cognitive function. Pilots' profile of cognitive performance deviates from that seen in the normal population, but mirrors that seen in other OP-exposed cohorts. In particular they show decrements in performance on tests of attention, psychomotor speed and visual sequencing. Given the safety implications of these findings, further research is warranted.