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Biomedical subjects

T J Fria

Publications and source records attributed to T J Fria.

At least 19 recordsLinked to original sources
PubMed1985

Hearing acuity of children with otitis media with effusion.

Hearing levels are reported for a cohort of 222 infants (aged 7 to 24 months) and 540 older children (aged 2 to 12 years) with otitis media with effusion (OME). The infants had an average speech awareness threshold of 24.6 dB hearing level (HL). The older group had mean bone conduction thresholds less than 10 dB HL, and air conduction thresholds averaged 27 dB HL; however, acuity was 7 dB less impaired at 2,000 Hz. The mean three-frequency pure tone average and speech reception threshold were 24.5 and 22.7 dB, respectively. Hearing acuity was not significantly related to age or previous duration of OME. The otoscopic observation of an air-fluid level or bubbles was associated with less hearing impairment; however, a predictive relationship between hearing levels and tympanogram characteristics could not be demonstrated.

Acoustic Impedance Tests↗
PubMed1985

The effects of hypothermia on the latencies of the auditory brain-stem response (ABR) in the rhesus monkey.

The effect of hypothermia on the ABR latencies was evaluated in 14 rhesus monkeys. Data from 6 preliminary experiments showed that middle ear pressure decreased with decreasing body temperature and consequently, all experiments were conducted on animals with tympanostomy tubes inserted to maintain constant middle ear pressure. All animals were sedated with curare and anesthetized with ketamine. Hypothermia was induced by applying ice packs to the animal's body. Rectal temperatures and the ABR to click stimuli were recorded at 3-5 min intervals over a temperature range of from 38 degrees C to 20 degrees C. The pattern of latency change is characterized by increasing latency with decreasing temperature, a greater rate of change for temporally later waves and increasing rate of change for any one wave with decreasing temperature. An exponential function was applied to the data and explained at least 93% of the variances in latency. In general, a single exponential identical for all waves of an animal explained the latency change between 37 and 26 degrees C. Below 26 degrees C, a second and sometimes a third function was required. These findings are similar to those reported previously and to those describing the effect of maturation on the ABR.

Animals↗
PubMed1985

Cause of hearing loss in the high-risk premature infant.

Bilateral hearing loss occurred in 9.7% of infants who survived despite very low birth weight (less than or equal to 1500 gm), 16.7% of infants who survived neonatal seizures, and 28.6% of infants who survived both low birth weight and neonatal seizures. All neonates received treatment in a single neonatal intensive care unit between 1976 and 1980. Twenty-two of 36 hearing-impaired children were normal physically and mentally, with IQ scores of greater than or equal to 85. Significant neonatal predictors of hearing loss in high-risk premature infants (less than or equal to 36 weeks gestation), as determined by multivariable testing, were prolonged respirator care, high serum bilirubin concentration, and hyponatremia. Exchange transfusions were associated with a decreased risk of hearing loss.

Audiometry, Evoked Response↗
PubMed1985

Otitis media with effusion in preschool children.

The incidence, prevalence, and natural history of otitis media with effusion (OME) and middle ear high negative pressure (HNP) were investigated in a group of 2 to 6 year old preschool children. The children were examined monthly over a two year period from September 1981 to August 1983. The middle ear status was assessed using a decision-tree algorithm which combined the findings of pneumatic otoscopy, tympanometry, and acoustic reflex measurements. Fifty-three percent of the children in the first year and 61% in the second year developed OME; also during the two years, HNP was documented in 66% of the children. Eighty percent of OME episodes lasted only two months. The prevalence of OME and HNP showed a seasonal variation and a strong association with the presence of upper respiratory infections (URIs). The incidence of OME was independent of age. These data indicate that OME and HNP are prevalent conditions with a high spontaneous recovery in the preschool population.

Audiometry, Pure-Tone↗
PubMed1984

Slow negative evoked potentials in the rhesus monkey (Macaca mulatta): myogenic versus neurogenic influences.

The influence of myogenic activity on the generation of slow negative evoked potentials (SN10) to octave, toneburst stimuli (0.5-2 Hz) was investigated in 5 rhesus monkeys (M. mulatta) by comparing responses obtained prior to and during total paralysis induced with curare. The SN10 could be easily elicited during paralysis, regardless of stimulus intensity, rate, or frequency. During paralysis, there were no systematic changes in either response latency or amplitude; variability in latency was less than 10% and changes in response amplitude were within 30%. These findings suggest that the myogenic contribution to the SN10 response is negligible and that this response is of neurogenic origin in the rhesus monkey.

Acoustic Stimulation↗
PubMed1983

Lack of efficacy of a decongestant-antihistamine combination for otitis media with effusion ("secretory" otitis media) in children. Results of a double-blind, randomized trial.

In a double-blind, randomized trial of 553 infants and children who had otitis media with effusion ("secretory" otitis media), we compared the efficacy of a four-week course of an oral decongestant-antihistamine combination (pseudoephedrine hydrochloride, 4 mg per kilogram of body weight per day, and chlorpheniramine maleate, 0.35 mg per kilogram per day) with that of placebo. Among patients with initially unilateral disease, resolution of middle-ear effusion occurred at four weeks in 38 per cent of those treated with placebo and 34 per cent of those treated with drug (P = 0.74). Among patients with initially bilateral disease the corresponding proportions were 19 and 21 per cent, respectively (P = 0.67). Side effects were reported more often among drug-treated than placebo-treated patients. Decongestant-antihistamine combinations do not appear to be indicated for the treatment of otitis media with effusion in infants and children.

Child↗
PubMed1983

Maturation of the auditory brain stem response in rhesus monkeys (Macaca mulatta).

To document the maturational changes in the auditory brain stem response (ABR) of the rhesus monkey, longitudinal and cross-sectional data were collected on a panel of 31 animals during the first year of life. Each ABR test consisted of averaging 2048 responses to click stimuli delivered at a rate of 21 clicks/sec and elicited at 60, 40, 20 and 10 dB HL intensities in accordance with procedures described previously. The morphology of the ABR wave form recorded at birth was similar to that at 12 months of age and the latencies of the component waves decreased exponentially over this period. The magnitude of decrease in latency was greatest for wave IV and least for wave I. The regression lines for the log of the latencies of 3 waves on age were computed for 3 animals followed longitudinally and for the cross-sectional data set. The slopes of these regression lines were different among animals, indicating differing rates of maturation. However, these slopes were identical for the component waves of any one animal, suggesting that the rate of maturation was constant over the auditory pathway. These changes were similar in pattern to those reported for human data and suggest that the rhesus monkey may serve as an appropriate model of auditory development in man.

Animals↗
PubMed1977

The clinical utility of ipsilateral stapedius reflex tests.

Ipsilateral stapedius reflex testing has been evaluated in 166 patients. It proves of value in defining the state of an ear (1) opposite to a unilateral conductive loss; (2) the less hard-of-hearing ear in the presence of bilateral asymmetrical sensorineural hearing losses where the worse ear has sufficiently severe loss to prevent a contralateral reflex from being elicited; (3) in patients with absent contralateral acoustic reflexes at 500, 1000, and 2000 Hz; and (4) in suspected central lesions. The test is still bedevilled by artifacts which are produced in the ear rather than the machine; atypical results must be evaluated with extreme caution.

Acoustic Impedance Tests↗
PubMedDate not supplied

Effects of rate of air pressure change on tympanometry.

The effects of two rates of air pressure change upon the pressure and compliance values and classification of tympanograms were determined in normal subjects and subjects with middle ear pathology. Significant differences in the magnitude of compliance and the air pressure corresponding to maximum compliance were observed. The more rapid rate was associated with a higher measured compliance in both groups of ears. In normal ears, the faster pressure change resulted in a shift in the point of maximum compliance toward a more negative pressure, while the reverse was true for ears with middle ear disease. The different rates of pressure change resulted in a different classification of the associated tympanograms for approximately 25% of the impaired ears. These findings imply that the interpretation of the relative normalcy of the tympanogram should take into account the rate of air pressure change used to acquire the result.

Acoustic Impedance Tests↗
PubMedDate not supplied

Maturation of the auditory brain stem response (ABR): additional perspectives.

A retrospective, cross-sectional analysis of component latencies of the auditory brain stem response (ABR) was performed on 466 patients ranging in age from 30 weeks postconception to adulthood. The ontogeny of ABR component wave latencies was adequately described by two exponential curves having different slopes; the steeper curve represented an early, rapid maturation ending by 8 to 10 weeks post partum, and the ensuing, more gradual curve corresponded to developmental events which were completed by the beginning of the third year of extrauterine life. These observations conform to previous maturational concepts of peripheral versus central segments of the auditory pathway and to the gradual decrease in interwave latencies with increasing age. Unlike interwave latency, however, the ratio of the latencies of selected component waves was constant with increasing age. This was especially apparent in developing newborns less than 50 weeks postconception. The nonlinear bases of this phenomenon are outlined, and the insights which stem from this perspective are discussed.

Adolescent↗
PubMedDate not supplied

Validation of an automatic otoadmittance middle ear analyzer.

Tympanometry and acoustic reflex measurements were performed with an automatic otoadmittance middle ear analyzer (MEA) on 40 otologically normal children and 172 children with a history of recurrent acute otitis media or otoscopic evidence of persistent otitis media with effusion (OME), or both. For children with OME, the measurements were taken within a one-hour period prior to myringotomy. Myringotomy findings were used to validate predictive schema aimed at determining admittance values associated with OME. Predictive accuracy was quantitifed with percent sensitivity and specificity values. The results show that the MEA demonstrated suitable diagnostic predictability, but this was significantly influenced by the schema chosen to interpret obtained admittance measures. The simple presence or absence of a tympanometric peak (regardless of gradient) yielded the highest sensitivity and specificity values, whereas the manufacturer's suggested approach, with or without the acoustic reflex, was not as successful. The implications of these results are discussed.

Acoustic Impedance Tests↗