How to interpret the diagnosis of pure tone audiometry results when encountering hearing loss
(A) Firstly, determine the nature of hearing loss in deaf patients
1, conductive hearing loss: air conduction hearing threshold is increased, bone conduction hearing threshold is normal, and the mean value of air-bone conduction difference is >l5dBHL.
2. Sensorineural hearing loss: both air-bone conduction hearing threshold is increased, and the mean value of air-bone conduction difference is <15dbhl.
3, mixed hearing loss: air-bone conduction hearing threshold is increased (bone conduction hearing threshold > 20dBHL), and air-bone conduction difference > 10dBHL.
(B) Secondly, to determine the degree of hearing loss in deaf patients
Based on the patient’s pure-tone audiogram, the average threshold of the patient’s binaural air conduction was calculated separately (the better hearing ear was used for those with binaural hearing loss). The degree of hearing loss was classified according to the following criteria
1. Normal hearing: <25dbhl< span="">
2.Mild hearing loss: 26 to 40dBHL
3.Moderate hearing loss:41～70dBHL
4.Severe hearing loss:71～90dBHL
5.Very severe hearing loss:>90dBHL
(C) Finalize the type of hearing curve for pure tone audiometry of the patient
Firstly, clarify the frequency range.
Low frequency: <0.5khz< span="">
Mid-frequency: >0.5kHz<2khz< span="">
High frequency: >2kHz<8khz< span="">
UHF: >8kHz
Common types of listening curves:
1, slopping (slopping) hearing curve: also known as high-frequency hearing loss type curve, the patient’s hearing gradually decreases with the increase of the test frequency, and its hearing loss is mainly 2KHz ~ 8KHz.
It is divided into the following three subtypes:
Slow-declining type: the hearing threshold increases by 5-10 dBHL per octave.
Significantly descending type: the hearing threshold increases by 15-2OdBHL per octave.
Steeply descending type: flat or slowly descending at the low and middle frequencies, followed by an increase of 25dBHL or more per octave threshold.
2, rising type (rising) hearing curve: the patient’s low frequency hearing is poor, as the test frequency increases its hearing threshold gradually decreases, so also known as low frequency hearing decline type curve.
3, flat (Fat) hearing curve: full-frequency hearing loss, the patient’s hearing loss of each frequency is basically the same degree.
4, valley type (va11ey) hearing curve: the middle frequency area than the two ends of the frequency threshold is 20dBHL or greater, hearing loss to 500 ~ 2KHz mainly, so also known as the middle hearing loss type.
5, notched type (notched): a single frequency at the threshold increased significantly, its adjacent frequencies quickly return to normal or close to normal.
6, mountain type (ridge): the middle frequency area than the high frequency, low end frequency threshold is 20dBHL or less.