Comment on "Ear Asymmetries in middle-ear, cochlear, and brainstem responses in human infants" [J. Acoust. Soc. Am. 123, 1504-1512].

Following Sininger and Cone-Wesson [Science 305, 1581], Sininger and Cone-Wesson [Hear. Res. 212, 203-211], Keefe et al. [J. Acoust. Soc. Am. 123(3), 1504-1512] described ear asymmetries in middle ear, cochlear, and brainstem responses of infants. Keefe et al. state that their data do not support the findings of Sininger and Cone-Wesson [Science 305, 1581] who found asymmetries in evoked otoacoustic emissions and auditory brainstem responses and proposed that stimulus-directed asymmetries in processing may facilitate development of hemispheric specialization. The Keefe et al. findings, in fact, replicated and extended the findings of Sininger and Cone-Wesson (2004, 2006) and support, rather than refute, the conclusions. Keefe et al. controlled neither the background noise nor averaging time across test conditions (ear or otoacoustic emission type) and thus their separate analyses of signal and noise magnitude exceed the limitations imposed by the data collection methods.