Effects of maturation on tympanometric wideband acoustic transfer functions in human infants.
Wideband acoustic transfer function (ATF) measurements of energy reflectance (ER) and admittance magnitude (|Y|) were obtained at varying static ear-canal pressures in 4-, 12-, and 27-week-old infants and young adults. Developmental changes in wideband ATF measurements varied as a function of frequency. For frequencies from 0.25 to 0.75 kHz there was as much as a 30% change in mean ER and mid |Y| with changes in static ear-canal pressure between 4 and 24 weeks of age. From 0.75 to 2 kHz, the effects of pressure produced a small number of significant differences in ER and mid |Y| with age, suggestive of a developmentally stable frequency range. Between 2 and 6 kHz, there were differential effects of pressure for the youngest infants; negative pressures caused increased ER and mid |Y| and positive pressures caused decreased ER and mid |Y|; the magnitude of this effect decreased with age. Findings from this study demonstrate developmental differences in wideband tympanometric ATF measurements in 4-, 12- and 24-week-old infants and provide additional insight on the effects of static ear-canal pressure in the young infant's ear. The maturational effects shown in the experimental data are discussed in light of known age-related anatomical changes in the developing outer and middle ear.
Sanford
Chris A
CA
Department of Speech and Hearing Sciences, University of Washington, Seattle, Washington 98105, USA.
Feeney
M Patrick
MP
D000158:Acoustic Impedance Tests; D000161:Acoustic Stimulation; D000328:Adult; D000367:Age Factors; D000375:Aging / Q000502:physiology; D003430:Cross-Sectional Studies; D004424:Ear Canal / Q000033:anatomy & histology / Q000254:growth & development*; D004432:Ear, Middle / Q000033:anatomy & histology / Q000254:growth & development*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous; D011312:Pressure; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult