Probe-tube microphone measures of ear-canal sound pressure levels in infants and children.

Probe-tube microphone measures of ear-canal sound-pressure levels were obtained for 31 children under 5 years of age. These data were compared to similar measures from a group of 21 adults. The intrasubject variability was smallest for the frequency range from 750 to 3000 Hz and at no frequency did the mean standard deviation exceed 3 dB. Real ear to coupler differences for the children showed the same pattern as a function of frequency as for adults but were significantly larger. A systematic decrease in real ear to coupler differences was observed with increasing age between 1000 and 3000 Hz. An estimate of ear-canal volume did not appear to be a clinically useful predictor of real ear to coupler differences.