Impedance measures and pure-tone screening of college students

Normative data from tympanometry and static compliance measures were presented for 355 freshmen entering college. Only one ear was tested. A lax criterion in tympanometry yielded a failure rate of 4%; pure-tone screening (20 db at 1 and 2 kc/s, 25 db at 4 kc/s) yielded a failure rate of 8%. In 90% of Ss the impedance (lax criterion) and pure-tone screening tests agreed in identifying an ear as normal or abnormal. Excluding 5% of the cases at each end of the continuum, 90% had static compliance in the range 0.30-1.15 cc; the middle 62% had compliance values of 0.45-0.89 cc. The distribution of tympanogram types and static compliance values were not significantly different for men and women, or for R and L ears. Impedance measures and pure-tone thresholds disagreed half the time on "Pass" and "Fail," although they showed the same proportions of "Pass" and "Fail," suggesting that two different aspects of hearing were being assessed.