Methods and reference data for middle ear transfer functions - Scientific Reports
Summary
Following basic preparation (removal of connective tissue and muscles), access to the middle ear is accomplished via mastoidectomy and subsequent posterior tympanotomy. The reference microphone, an ER-7C (Etymotic Research Inc., USA), was inserted through a close-fitting hole drilled into the anterior side of and perpendicular to the ear canal, ending 2–3 mm in front of the TM. The reference microphone (either Bruel & Kjær 4182 or G.R.A.S 46BF) was inserted into the ear canal along with the loudspeaker (either Pyle PDWP5BK or Tucker Davis Technology), with the tip of the probe about 1 mm away from the TM. Excitation signals were generated with a custom made MATLAB program, and consisted of a series of single sine waves for multiple frequencies starting at 100 Hz and spaced logarithmically at ¼ octave intervals. We are using the Holm method of sequentially rejective testing to avoid summation of type I errors (false positives)26 and denote the corresponding adjusted p value as \({p}_{adj}\).