Middle ear muscle reflex measurement in neonates: Comparison between 1000 Hz and 226 Hz probe tones

IntroductionMiddle ear muscle reflex (MEMR) evaluation assists in diagnosing hearing problems because normal responses depend on preconditions of a healthy auditory system. Studies in neonates recording the acoustic reflex with 226 Hz probes have described high rates of absence. Other studies using a high frequency probe have found higher rates of presence in normal neonates. However, few studies have compared results between low and high frequency probes in the same newborns.ObjectiveTo comparatively assess the ipsilateral acoustic reflex recorded by 226 Hz and 1000 Hz probes in newborns.MethodA total of 77 newborns, with the presence of transient otoacoustic emissions, underwent tympanometry, wideband acoustic immittance, and ipsilateral reflex investigations with 226 Hz and 1000 Hz tone probes.ResultsThe acoustic reflex was activated at a much lower intensity with all activating stimuli using the 1000 Hz probe compared with the values of the 226 Hz probe. There was a higher incidence of ipsilateral acoustic reflexes recorded by the 1000 Hz tone probe compared to the 226 Hz tone probe. There was no correlation between the acoustic reflex thresholds and otoacoustic emissions.ConclusionIn newborns, the acoustic reflex measurements obtained with the 1000 Hz probe showed advantages over the 226 Hz probe.