ObjectiveTodetectearlysignsofnoise-inducedhearingloss(NIHL)inmilitarypilotswithouthearingcomplaints.MethodsPuretoneaudiometryandacousticreflexthresholdsweretestedin36militarypilots(72ears)withnoiseexposurehistorybutnocomplaintsofhearingloss.Conventionaltestfrequencies(0.25-8kHz)andextendedhighfrequencies(EHF,10and12.5kHz)wereincludedinaudiometry.Whitenoiseandpuretonesat0.5,1,2,and4kHzwereusedforacousticreflextests.Twentynormalhearingsubjects(40ears)withnoexposuretooccupationalnoisewereusedascontrols.ResultsPuretonethresholdsatallconventionalfrequenciesandatEHFswereelevatedinthepilots,withthemaximumshiftat4kHz,comparedwithcontrols(p<0.01).ThepilotsalsoshowedelevatedARTtowhitenoiseanddecreaseddifferentialsbetweenwhitenoiseandpuretoneARTs(p<0.01).ConclusionEarlysignsofNIHLarepresentinsomesymptom-freemilitarypilots.Highfrequencyhearingthresholdshift,elevatedwhitenoiseARTanddecreaseddifferentialbetweenwhitenoiseandpuretoneARTsmaybeobjectiveindicatorsofearlyNIHL.
