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Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neonates younger than the age of 12 weeks (10 full-term, 20 preterm) had an audiological assessment consisting of brainstem audiometry, tympanometry, transiently evoked otoacoustic emissions, and spontaneous otoacoustic emissions with contralateral white noise stimulation. Results from brainstem audiometry, tympanometry, and transiently evoked otoacoustic emissions suggested normal middle ear function and normal cochlear function. All full-term neonates had multiple spontaneous otoacoustic emissions, and contralateral white noise stimulation resulted in enhancement of emissions in 80%, whereas in 20% the emissions were suppressed. In preterm neonates, spontaneous otoacoustic emissions were present in 55%. These emissions were mostly solitary and, in 64%, showed suppression with contralateral white noise stimulation. Embryological data taken into consideration suggest that the pattern of spontaneous otoacoustic emissions in preterm neonates is more likely related to immaturity of the central auditory pathway rather than the cochlea.
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PMID:Spontaneous otoacoustic emissions in neonates and effect of contralateral white noise stimulation. 1468 37

The authors evaluated mutual relationships between transiently evoked otoacoustic emissions (TEOAE) and various parameters defining perinatal period focusing mostly on hypotrophic newborns. TEOAE was collected using 2.5-12.5 msec time-window. TEOAE amplitude and responses (S/N ratio) from various frequency bands calculated using off-line analysis were collected using ILO 88 ECHOPORT Otodynamics. Half-octave frequency bands centered at 1.0, 1.5, 2.0, 3.0, and 4.0 kHz were included to this study. All 370 newborns, 1 to 5 days old, were tested bilaterally. The relationship between TEOAE and birth weight in all newborns showed positive correlation. Weaker TEOAE amplitudes and off-line calculated responses at low and middle frequency bands were associated with middle ear status and with immaturity of the cochlea. This tendency was specifically strong in preterm neonates with very low birth weight. The separated subgroup of hypotrophic newborns with Apgar score <7 was characterized by statistically significant weakening TEOAE amplitude and off-line calculated responses at the whole frequency band. Such results may suggest that perinatal hypoxia affect the outer hair cell function at the whole length of the basilar membrane. Co-existing factors such as intrauterine hypotrophy and perinatal hypoxia affect the cochlear function significantly deeper than each of them working separately.
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PMID:[Effects of intrauterine hypotrophy and perinatal hypoxia on cochlear function evaluated by click evoked otoacoustic emissions (TEOAE)]. 1530 86

Our aim in the present study was to apply extrapolated DPOAE I/O-functions [J. Acoust. Soc. Am. 111, 1810-1818 (2002); 113, 3275-3284 (2003)] in neonates in order to investigate their ability to estimate hearing thresholds and to differentiate between middle-ear and cochlear disorders. DPOAEs were measured in neonates after birth (mean age = 3.2 days) and 4 weeks later (follow-up) at 11 test frequencies between f2 = 1.5 and 8 kHz and compared to that found in normal hearing subjects and cochlear hearing loss patients. On average, in a single ear hearing threshold estimation was possible at about 2/3 of the test frequencies. A sufficient test performance of the approach is therefore suggested. Thresholds were higher at the first measurement compared to that found at the follow-up measurement. Since thresholds varied with frequency, transitory middle ear dysfunction due to amniotic fluid instead of cochlear immaturity is suggested to be the cause for the change in thresholds. DPOAE behavior in the neonate ears differed from that found in the cochlear hearing loss ears. From a simple model it was concluded that the difference between the estimated DPOAE threshold and the DPOAE detection threshold is able to differentiate between sound conductive and cochlear hearing loss.
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PMID:Distortion product otoacoustic emissions for hearing threshold estimation and differentiation between middle-ear and cochlear disorders in neonates. 1595 67

Distortion product otoacoustic emission (DPOAE) measures of cochlear function, including DPOAE suppression tuning curves and input/output (I/O) functions, are not adultlike in human infants. These findings suggest the cochlear amplifier might be functionally immature in newborns. However, many noncochlear factors influence DPOAEs and must be considered. This study examines whether age differences in DPOAE I/O functions recorded from infant and adult ears reflect maturation of ear-canal/middle-ear function or cochlear mechanics. A model based on linear middle-ear transmission and nonlinear cochlear generation was developed to fit the adult DPOAE I/O data. By varying only those model parameters related to middle-ear transmission (and holding cochlear parameters at adult values), the model successfully fitted I/O data from infants at birth through age 6 months. This suggests that cochlear mechanics are mature at birth. The model predicted an attenuation of stimulus energy through the immature ear canal and middle ear, and evaluated whether immaturities in forward transmission could explain the differences consistently observed between infant and adult DPOAE suppression. Results show that once the immaturity was compensated for by providing infants with a relative increase in primary tone level, DPOAE suppression tuning at f2= 6000 Hz was similar in adults and infants.
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PMID:Effects of middle-ear immaturity on distortion product otoacoustic emission suppression tuning in infant ears. 1734 21

The "wait and see" approach in acute otitis media (AOM), consisting of postponing the antibiotic administration for a few days, has been advocated mainly to counteract the increased bacterial resistance in respiratory infections. This approach is not justified in children less than 2 years of age and this for several reasons. First, AOM is an acute inflammation of the middle ear caused in about 70% of cases by bacteria. Redness and bulging of the tympanic membrane are characteristic findings in bacterial AOM. Second, AOM is associated with long-term dysfunction of the inflamed eustachian tube (ET), particularly in children less than 2 years of age. In this age group, the small calibre of the ET together with its horizontal direction result in impaired clearance, ventilation and protection of the middle ear. Third, recent prospective studies have shown poor long-term prognosis of AOM in children below 2 years with at least 50% of recurrences and persisting otitis media with effusion (OME) in about 35% 6 months after AOM. Viruses elicit AOM in about 30% of children. A prolonged course of AOM has been observed when bacterial and viral infections are combined because viral infection is also associated with ET dysfunction in young children. Bacterial and viral testing of the nasopharyngeal aspirate is an excellent tool both for initial treatment and recurrence of AOM. Antibiotic treatment of AOM is mandatory in children less than 2 years of age to decrease inflammation in the middle ear but also of the ET particularly during the first episode. The best choice is amoxicillin because of its superior penetration in the middle ear. Streptococci pneumoniae with intermediary bacterial resistance to penicillin are particularly associated with recurrent AOM. Therefore the dosage of amoxicillin should be 90 mg/kg per day in three doses. In recurrent AOM with beta-lactamase-producing bacilli, amoxicillin should be associated with clavulanic acid at a dose of 6.4 mg/kg per day. The duration of the treatment is not established yet but 10 days is reasonable for a first episode of AOM. OME may be a precursor initiating AOM but also a complication thereof. OME needs a watchful waiting approach. When associated with deafness for 2-3 months in children over 2 years of age, an antibiotic should be given according to the results of the bacterial resistance in the nasopharyngeal aspirate. The high rate of complications of tympanostomy tube insertion outweighs the beneficial effect on hearing loss. The poor results of this procedure are due to the absence of effects on ET dysfunction. Pneumococcal vaccination has little beneficial effects on recurrent AOM and its use in infants needs further studies. Treatment with amoxicillin is indicated in all children younger than 2 years with a first episode of AOM presenting with redness and bulging of the tympanic membrane. Combined amoxicillin and clavulanic acid should be given in patients with beta-lactamase-producing bacteria. The duration of treatment is estimated to be at least 10 days depending on the findings by pneumo-otoscopy and tympanometry. Bacterial and viral testing of the nasopharyngeal aspirate is highly recommended particularly in children in day care centres as well as for regular follow-up. The high recurrence rate is due to the long-lasting dysfunction of the eustachian tube and the immune immaturity of children less than 2 years of age.
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PMID:What is new in otitis media? 1736 73

Otitis media (OM) is a pervasive illness in infants and children, and many children suffer multiple episodes during the first years of life. High rates of acute otitis media (AOM) are reported in developed and emerging countries. Early onset is common in both settings. Recurrent OM is associated with several factors, including early onset of disease, having a sibling with a history of AOM and absence of breast-feeding. Early onset disease has been hypothesized to result from Eustachian tube dysfunction, immunologic naivete and immaturity, and viral upper respiratory tract infection. Nasopharyngeal colonization with bacterial otopathogens increases the likelihood of AOM and the disease is most frequent in children with viral respiratory tract infection colonized with multiple otopathogens (Streptococcus pneumoniae, nontypeable Haemophilus influenzae [NTHi], Moraxella catarrhalis), potentially as a result of inflammation resulting from competition among the bacterial species within the nasopharynx. Epidemiologic observations and studies of pathogenesis suggest that successful strategies for reducing the burden of disease will be best accomplished by targeting multiple viral and/or bacterial pathogens and preventing early onset disease. Guidelines (2004) for the treatment of AOM in children establish a clear hierarchy among the various antibacterials for the treatment of this disease. Failure to achieve early bacterial eradication during antibiotic therapy for AOM increases the clinical failure rates in AOM in young children. Most recurrent AOM episodes occurring within 1 month after successful completion of antibiotic therapy are due to new otopathogens. Failure to eradicate middle ear and/or nasopharyngeal pathogens is associated with higher rates of clinical recurrent AOM, even when the patients show clinical improvement or cure at the end of therapy for the initial episode. Optimal strategy for the prevention of AOM recurrences requires sterilization of the middle ear and eradication of nasopharyngeal carriage of otopathogens during antimicrobial therapy.
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PMID:Recent advances in otitis media. 1991 36

Acute otitis media (AOM) is a common disease in young children. Streptococcus pneumoniae (Spn) and Haemophilus influenzae (NTHi) are the two most common pathogens that cause AOM. Over the past 5 years, our group has been studying the immunologic profile of children that experience repeated AOM infections despite tympanocentesis drainage of middle ear fluid and individualized antibiotic treatment; we call these children stringently-defined otitis prone(sOP). Although protection against AOM is primarily mediated by ototpathogen-specific antibody, our recent studies suggest that suboptimal memory B and T cell responses and an immaturity in antigen-presenting cells may play a significant role in the propensity to recurrent AOM infections. This review focuses on the studies performed to define immunologic dysfunction in sOP children.
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PMID:Cellular immune response in young children accounts for recurrent acute otitis media. 2402 64


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