Middle Ear Fluid at Birth at Risk for Chronic Middle Ear Infection

Newborn hearing screening is strongly endorsed by the Centers for Disease Control (CDC). The government agency states that such programs should aim for having all infants screened for hearing loss by one month of age, preferably before discharge from a hospital. The CDC offers that "the age of a child when a hearing impairment is diagnosed is crucial to the development of the child's speech, language, cognitive, and psychosocial abilities."

While screening leads to identification of significant sensorineural hearing loss in approximately three to five in 1000 infants screened, three to five percent of infants typically fail the screen. Many "failures" on newborn hearing screening tests are attributed to middle ear fluid (effusion) in the newborn period. Medical researchers do not know whether effusion in the newborn period is a risk factor for the development of chronic otitis media with effusion (COME). Otitis media is the most frequently diagnosed condition in office practice for children under the age of 15, and results in approximately 30 million physician visits annually. Two-thirds of all children in the U.S. have at least one episode of otitis media by their third birthday; up to one-half have had three or more episodes.

Recent evidence points to genetic predisposition for COME, indicating that middle ear effusion may be congenital. Accordingly, a team of researchers set out to determine (1) whether newborn middle ear effusion present at age 30 to 48 hours is related to later diagnosis of COME during the first year of life; (2) if infants with neonatal middle ear effusion have significantly more episodes of middle ear effusion during the first year of life than infants without neonatal middle ear effusion; (3) if infants with neonatal middle ear effusion have hearing loss during the first year of life as compared to infants without neonatal middle ear effusion.

Karen Jo Doyle MD PhD, Ying Yee Kong, Karen Strobel, Patricia Dallaire, R. Mark Ray MD, all from the University of California Davis Medical Center, Sacramento, CA, are the authors of the study, "Persistent Neonatal Middle Ear Effusion Predicts Chronic Otitis Media with Effusion." They will present their findings at the annual meeting of the American Otological Society http://itsa.ucsf.edu/~ajo/AOS/AOS.html being held May 3-4, 2003, at the Gaylord Opryland Hotel, Nashville, TN.

Methodology: The study objective was to determine whether ears with middle ear effusion at 30 to 48 hours of age are significantly more likely to develop COME than ears without neonatal effusion. Control and experimental subject groups were recruited in the first 30 to 48 hours following birth. These two groups were placed in a prospective follow-up study to compare the groups' incidences of COME effusion and audiologic test results.

Study infants were recruited from 454 newborn infants who underwent infant hearing screening by transient-evoked otoacoustic emissions (TEOAEs) and pneumatic otoscopy. Age in hours at the time of screening was 30 to 48 hours. There were 30 infants identified with neonatal middle ear effusion in at least one ear (seven percent), although there were an additional 18 infants in whom vernix occluded the canal and prevented a view of the tympanic membrane. After exclusions and loss to follow-up, fourteen experimental and fifteen control subjects completed the one-year study. The experimental group had 10 male and four female infants; the control group had eight male and seven female infants. Average ages at hearing screen/initial otoscopy were 39.5 hours and 38.9 hours for the experimental and control groups, respectively.

Infant hearing screening took place in a quiet room in the well-baby nursery. Outpatient study tests included TEOAEs, tympanometry, pneumatic otoscopy, and visual-reinforcement audiometry (VRA, starting at age six months), at three, six, nine, and 12 months of age. Experimental (neonatal effusion) infants were followed starting at age one month. Infants found to have effusion on otoscopy at any follow-up examination were followed and tested one month later.

Results: Key findings from this research were:

-- Otoscopic Examinations. Eight experimental (58 percent) and three control (20 percent) babies developed COME over the first year of life. The average number of monthly examinations at which experimental infants had effusions was 4.14 (including three-month and later examinations.) The control group averaged 1.27 examinations with effusion present. These differences were statistically significant.

-- Tympanometric Results. A total of 340 otoscopic examinations were performed (170 visits). Tympanometry could not be performed due to infant crying or fussing only 17 times (five percent.) Excellent agreement was found between tympanometry results and pneumatic otoscopic results (91 percent). There were 21 instances where pneumatic otoscopy indicated middle ear effusion in ears with type A (8) or C (13) tympanograms. There were eight examinations where normal pneumatic otoscopic examinations were in disagreement with Type B tympanograms.

-- TEOAE Results. Emissions testing could be performed 86 percent of the time (93 percent of the time at age one month (experimental infants only), 91 percent of the time at age three months (both groups combined), 93 percent of the time at age six months (both groups combined), 86 percent of the time at age nine months, and only 74 percent of the time at age 12 months (due to infant crying or fussing.) When otoscopy revealed effusion (120 ears), TEOAEs could not be recorded 73.3 percent of the time. There were only nine instances where ears with normal pneumatic otoscopy failed emissions testing.

-- Audiometric Results. At age six months, only 43 percent of experimental versus 73 percent of control infants could be conditioned to perform visual reinforcement audiometry for speech. At the nine-month visits, 86 percent of experimental infants could be conditioned to perform VRA to speech, versus 73 percent of control infants. At age twelve months, 93 percent of experimental versus 87 percent of control infants were conditionable to speech VRA. At the nine-month visits, average speech VRA thresholds were 15.4 dB HL and 11.8 dB HL for the experimental and control groups, respectively; at twelve months, the average VRA thresholds were 12.7 dB HL for the experimental group and 9.62 dB HL for the control group, neither scores were statistically significant. Average mean pure tone thresholds were always worse for the experimental group than for the control group by 2 to 10 dB. For the control group, mean VRA thresholds never exceeded 25 dB HL. For the experimental group, mean VRA thresholds exceeded 25 dB HL at 1000, 2000, and 4000 Hz at nine months.

Conclusions: The results of this study indicate that infants who fail otoacoustic emissions screening due to middle ear effusion may be at increased risk for later development of COME. In this study, seven percent of neonates aged 30-48 hours had persistent middle ear effusion in at least one ear. This is comparable to previous research which found incidence of effusion of 11 percent and nine percent, using pneumatic otoscopy.

Five experimental infants had middle ear effusions on their one-month follow-up examinations, so that the condition of the middle ears at one month of age could predict COME, though not as strongly as the neonatal examination. Similarly, by age three months, five of the eight experimental infants who developed COME had abnormal otoscopic examinations. These results are in agreement with prior investigations that found that infants with onset of otitis media with effusion before age two months were significantly more likely to develop bilateral COME than infants with later onset otitis media with effusion.