The goal of this descriptive study is to collect the wideband immittance data in Thai normal hearing and conductive hearing loss adults. The main questions it aims to answer are:

1. What is normative data of wideband acoustic immittance in Thai normal hearing adults

2. What is the wideband acoustic immittance data in Thai conductive hearing loss who have type A, AS and Ad tympanogram Participants will examine hearing tests consequently

   • pure tone audiometry
   • Tympanometry with ipsilateral acoustic reflex
   • Wideband acoustic immittance

Inclusion Criteria:

Normal group

1. Thai adults (18-60 years old)
2. Pure-tone air-conduction thresholds ≤ 25 dB HL, measured at audiometric frequencies 250, 500, 1000, 2000, 3000, 4000, 6000 and 8000 Hz and air-bone gab < 10 dBHL at frequencies 500, 1000, 2000 and 4000 Hz
3. Type A tympanogram with present ipsilateral acoustic reflex
4. No diagnosis of middle ear disease
5. No history of middle ear surgery
6. Normal finding in otoscopic examination

Conductive hearing loss group

1. Thai adults (18-60 years old)
2. Pure-tone air-conduction thresholds > 25 dB HL, measured at audiometric frequencies 250, 500, 1000, 2000, 3000, 4000, 6000 and 8000 Hz and air-bone gab > 10 dBHL at frequencies 500, 1000, 2000 and 4000 Hz at least 2 frequencies in one ear
3. Type A, As or Ad tympanogram with absent ipsilateral acoustic reflex
4. Normal finding in otoscopic examination
5. There is an appointment for exploration middle ear within 2 months

Exclusion Criteria:

1. Have previously had middle ear surgery
2. Have an earache
3. Type B or C tympanogram
4. Volunteers who do not cooperate in audiometry test or unable to do audiometry test

Thai adults 18 to 59 years old who have normal hearing 245 participants and conductive hearing loss 45 participants