Characterization of spontaneous otoacoustic emissions in full-term newborns.
Level 4 - case-series / case-control
Cross-sectional observational study evaluating physiological parameters in healthy neonates
PubMed 25468465 · doi:10.1016/j.ijporl.2014.10.035
What was done
Authors measured spontaneous otoacoustic emissions (SOAEs) in 147 randomly selected full-term Chinese neonates (82 females, 65 males; 236 total ears) who passed newborn hearing screening. Testing was conducted in a sound booth using Capella OAE equipment to determine prevalence, signal level, frequency distribution, and number of emission peaks by sex and ear laterality.
What was found
- Overall SOAE prevalence was 56.77% across all tested ears. - Prevalence was significantly higher in females (69.23%) than in males (41.51%, p < 0.01) and in right ears (64.17%) than in left ears (49.14%, p < 0.05). - Overall mean SOAE level was 11.78 ± 8.36 dB SPL, with no significant differences between females (11.81 ± 8.43 dB SPL) and males (11.73 ± 8.25 dB SPL) or between left (11.97 ± 8.56 dB SPL) and right ears (11.65 ± 8.22 dB SPL). - Frequency percentiles (25th–75th) were significantly higher in females (2.31–4.36 kHz) than in males (1.93–3.94 kHz, p < 0.01), with no significant difference between right (2.17–4.14 kHz) and left ears (2.22–4.18 kHz). - The mean number of SOAE peaks was 3.70 ± 2.75, with no significant difference between sexes (females 3.62 ± 2.70 vs. males 3.86 ± 2.87) or ears (right 3.70 ± 2.55 vs. left 3.70 ± 3.02).
Why it matters
This study establishes baseline characteristics of SOAEs in healthy newborns, confirming that female-predominant and right-ear-predominant cochlear emission patterns are already present at birth.
Limits
The study was cross-sectional in full-term Chinese infants only, limiting generalizability to preterm infants or other ethnic groups. Only 236 of a potential 294 ears from the 147 infants were evaluated, with reasons for unmeasured ears not detailed in the abstract.
Cited by
- supports Females produce more spontaneous otoacoustic emissions than males, a sex difference that is already present at birth.