Temperature dependency of the frequency and level of a spontaneous otoacoustic emission during fever.

Using a method of heterodyne mixing with display of beats on a chart recorder, measurements were made of the frequency and level of a spontaneous otoacoustic emission in a human subject on 17 occasions during a period of 13 consecutive days. Temperature measurement was obtained with a thermometer measuring infra-red radiation from the ear-drum, indicative of body core temperature. In the latter half of this period there was variation of body set point temperature due to fever, and it was found that there was clear evidence of inverse relationship between temperature and both the frequency and level of the emission. The occurrence of fever was due to simple urinary tract infection and was considered to be without ototoxic implication; there was no associated worsening of pure tone threshold nor change in measurements of middle ear function.