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Biomedical subjects

L Birch

Publications and source records attributed to L Birch.

44 records · Page 3Linked to original sources
PubMed1985

Daily impedance audiometric screening of children in a day-care institution. Changes through one month.

Fifty-seven children in a fairly new day-care institution were examined daily by impedance audiometry through 4 weeks. A Madsen Electronics ZS 330 tympanoscope was used. The tympanometric curves were divided into types A, C1, C2, and B, indicating pressures over -99 mmH2O, from -100 to -199 mmH2O, below -199 mmH2O and completely flat curves, but in cases in which the compliance was less than 0.25 ml, combined with an absent ipsilateral stapedial reflex, were also interpreted as type B. The object was to ascertain how quickly the types changed and how stable the B curves were. Types A + C1, C2, and B changed daily into other types in 4.3%, 32.8%, and 9.5% respectively. A total of 43 episodes of B curves occurred. Of them 16 lasted for only one day and thereamongst 9 became quite flat. Only a few lasted for 8-23 days and 8 for 26 days or over.

Acoustic Impedance Tests↗
PubMed1984

A prospective epidemiological investigation of secretory otitis media and tubal dysfunction in children attending day-care centers. Serial tympanometry with an interval of two weeks.

The present investigation included 373 children aged 9 months to 7 years, cared for in nine kindergartens and one nursery home. Serial tympanometries were carried out at 2-week intervals. A Madsen Electronics ZS 330 tympanoscope was used for the measurements. To identify A, C1, C2 and B tympanograms, middle ear pressure, compliance and stapedial reflex were measured. After correction for age and other factors which could influence the prevalence of B and C2 tympanograms (number of siblings and parental smoking, which was included in an investigation of the indoor environment of the same children), no significant difference was found in the prevalence of these types of tympanograms, even though the number of children attending the different day-care centers ranged from 19 to 72. No significant difference was found in the prevalence of the A, C1, C2 and B tympanograms between right and left ears, but there was a significant difference in the prevalence of the A tympanograms in boys and girls, but not in C1, C2 and B tympanograms. The maximum prevalence of B tympanograms was found in 1-year-old children, decreasing to the age of 7 years.

Acoustic Impedance Tests↗
PubMed1984

Prospective epidemiological investigation of secretory otitis media in children attending day-care centers.

Screening tympanometries were performed at 2-week intervals in 373 children (mean age 4 1/4 years) cared for in 10 day-care centers in order to evaluate the incidence of secretory otitis media (SOM). The incidence was found to depend on the age of the children and the maximum level was at the age of 1 (0.36/child/month); the mean incidence was 0.16/child/month. The highest incidence and the largest number of children with prolonged SOM were both found in the 1-year-olds. The overall morbidity of SOM in the 373 children was 56%.

Acoustic Impedance Tests↗
PubMedDate not supplied

Child factor in measurement dependability.

A primary consideration in longitudinal growth studies is the identification of growth from error components. While previous research has considered matters of measurement accuracy and reproducibility in detail, few reports have investigated the errors of measurement due to aspects of the physiology and cooperation of the child. The present study directly assesses this source of measurement undependability for the first time. Investigation of total measurement error variance in 925 recumbent length replicates taken over stasis intervals in growth identifies that between 60% and 70% of total measurement unreliability is due to a child factor undependability. Individual differences are significant and longitudinal growth analyses should consider two to three times the technical error of measurement statistic as a reasonable estimate of the total unreliability for any single measurement of an infant's recumbent length. These results raise issues regarding analytic methods as applied to serial growth data.

Analysis of Variance↗
PubMedDate not supplied

Middle ear effusion in children and the indoor environment: an epidemiological study.

A prospective study of 337 children was carried out during a 3-month period. The purpose of the study was to evaluate the importance of indoor environmental factors in homes and day-care institutions for the incidence of middle ear effusion (MEE). The indoor environmental factors measured in institutions were carbon dioxide, temperature, and relative humidity. Conditions in the homes were assessed by a questionnaire. Middle ear effusion was measured by tympanometry. No relationship was found between indoor environmental factors and MEE, with the exception of parental smoking at home, which increased the frequency of MEE in children.

Acoustic Impedance Tests↗
PubMedDate not supplied

Presence of interferon in the middle ear during secretory otitis media.

In connection with grommet insertion due to secretory otitis media (SOM), the middle ear effusion was collected and studied for content of interferon and bacteria. The study material comprised a total of 47 ears in 29 children, but from 10 ears the effusion was too viscous for interferon titration, so only 24 children were ultimately included. Interferon was present in 5 ears of 3 children. A child having a low titre in both ears had recently been treated with penicillin. From the other 2 children, pneumococci were cultured. Twelve of the included children had a common cold, but of them only 2 had interferon in the middle ear. The production of interferon was presumably induced by the pneumococci, not by virus.

Adolescent↗