Selected studies investigating the prevalence of hearing loss in cystic fibrosis (CF)
| Author | Study methods | Definition of HI | Results |
| Forman-Franco et al, 197949 | PTA using frequencies 250, 500, 1000, 2000, 4000, 8000 Hz. Recruited from a CF clinic (n=80) | Air conduction thresholds for ≥2 frequencies >25 dB | 1/80 (1%) had HI |
| Pedersen et al, 198711 | PTA (frequency range 125–8000 Hz). High-frequency audiogram from 4000–20 000 Hz. All patients had chronic P aeruginosa (n=42) | Threshold increased by ≥15 dB in one or both ears at two or more adjacent frequencies | 2/42 patients (5%) had high-frequency HI. Both patients had normal thresholds <8000 Hz |
| Mulheran et al, 200130 | PTA over frequencies 250–8000 Hz. High-frequency PTA over 10 000–16 000 Hz (n=70) | ≥2 thresholds in either ear of ≥20 dB or one frequency of ≥25 dB over the frequency range 250–8000 Hz | 17% had HI |
| Conrad et al, 200840 | Annual audiometric assessment of patients at two CF clinics with PTA over frequency range 1000–8000 Hz. DPOAE were measured over the frequency range 841–7996 Hz (n=153) | Either one PTA threshold >25 dB or abnormal DPOAE thresholds | 50.8% had abnormal hearing |
DPOAE, distortion product otoacoustic emissions; HI, hearing impairment; PTA, pure tone audiogram.