The mechanical impedances of mastoids of some normal and deaf subjects

Measurements of the mechanical impedance of mastoids of thirteen normal subjects and three deaf subjects have been made. It is shown that between 400 and 4000 c/s the mastoid behaves approximately as a simple series resonant system, and that there appears to be a significant difference between the mean values of compliance, mass and resistance for normal subjects and those for mastoids which experience the continuous pressure of bone-conduction receivers. Results have also been obtained, showing the dependence of the impedance upon the area and applied force of the measuring surface.