Differences in distortion product otoacoustic emission phase recorded from human neonates using two popular probes.
DPOAE (2f(1)-f(2)) phase was measured across a 3-octave frequency range from two groups of newborns using ER10B+ and ER10C probe microphones. A marked phase shift was noted in the mid-to-high frequency range for newborn data recorded with the ER10C only. In contrast, the ER10B+ produced phase that was approximately invariant as a function of frequency for most of the range. Probe-related phase shifts can be effectively eliminated by correcting for variations in the phases of the primary tones. Results highlight the importance of detecting and correcting for system-related phase shifts so they are not misinterpreted as cochlear in origin.
Abdala
Carolina
C
Division of Communication and Auditory Neuroscience, House Ear Institute, 2100 W Third Street, Los Angeles, California 90057, USA. cabdala@hei.org
Dhar
Sumitrajit
S
D000161:Acoustic Stimulation; D000328:Adult; D000367:Age Factors; D000669:Amplifiers, Electronic; D002138:Calibration; D004867:Equipment Design; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D034381:Hearing Loss / Q000175:diagnosis* / Q000503:physiopathology; D006320:Hearing Tests / Q000295:instrumentation* / Q000592:standards; D006801:Humans; D007231:Infant, Newborn; D015141:Los Angeles; D008297:Male; D015997:Neonatal Screening / Q000295:instrumentation* / Q000592:standards; D017084:Otoacoustic Emissions, Spontaneous; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted