Table 1.
Classifications and criteria for degree and type of hearing loss, tympanometry and hearing symmetry, and longitudinal hearing change.
| Classification | Criteria | |
|---|---|---|
| Degree of HL a | ||
| None | ≤ 15 dB HL | |
| Slight | > 15 and ≤ 25 dB HL | |
| Mild | > 25 and ≤ 40 dB HL | |
| Moderate | > 40 and ≤ 70 dB HL | |
| Severe | > 70 and ≤ 95 dB HL | |
| Profound | > 95 dB HL | |
| Type of HL b | ||
| None | AC ≤ 15 dB HL | |
| Conductive | AC >15 dB HL; BC ≤ 15 dB HL; ABG > 10 dB | |
| Mixed | BC > 15 dB HL; ABG > 10 dB | |
| Sensorineural | AC > 15 dB HL; ABG ≤ 10 dB | |
| Unknown | AC > 15 dB HL; unknown BC | |
| Tympanometry | Adult | Child (3–5 years) |
| Normal c | 0.3–1.4 cc; > −100 daPa | 0.2–0.9 cc; > −100 daPa |
| Immobile (flat) | No mobility, no peak | No mobility, no peak |
| Eustachian tube Dysfunction | < −100 daPa | < −100 daPa |
| Hypermobility | > 1.4 cc, > −100 daPa | > 0.9 cc, > −100 daPa |
| Hypomobility | < 0.3 cc, > −100 daPa | < 0.2 cc, > −100 daPa |
| HL asymmetry | > 10-dB difference in at least two consecutive frequencies (of 0.25, 0.5, 1, 2, 4, and 8 kHz) with better-hearing ear > 15 dB 4F-PTA (AC). | |
| Longitudinal change d | ||
| Stable | No significant fluctuation, improvement, or progression | |
| Improvement | 10-dB improvement at any three frequencies, 15-dB improvement at any two frequencies, or ≥ 20-dB improvement at one frequency | |
| Progressive | 10-dB decline at any three frequencies, 15-dB decline at any two frequencies, or ≥ 20-dB decline at any one frequency | |
| Fluctuating | Interim audiogram shows 10-dB change at any three frequencies, 15-dB change at any two frequencies, or ≥ 20-dB change at any one frequency, and final audiogram does not show significant improvement or progression from baseline | |
| Fluctuating/improvement | Interim audiogram shows 10-dB change at any three frequencies, 15-dB change at any two frequencies, or ≥ 20-dB change at any one frequency, and final audiogram shows significant improvement from baseline | |
| Fluctuating/progressive | Interim audiogram shows 10-dB change at any three frequencies, 15-dB change at any two frequencies, or ≥ 20-dB change at any one frequency, and final audiogram shows significant progression from baseline | |
Note. Three frequencies (0.5, 1, and 2 kHz). Four frequencies (0.5, 1, 2, and 4 kHz). HL = hearing loss; AC = air conduction; BC = bone conduction; ABG = air–bone gap; PTA = pure-tone average. 4F-PTA = four-frequency pure-tone average.
a
On the basis of 4F-PTA by AC.
b
On the basis of three-frequency pure-tone average for AC and BC or, less commonly, by speech threshold in ears with some degree of HL by 4F-PTA, ABG.
d
Required a minimum of four audiograms spanning at least 2 years.