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Biomedical subjects

P Bonding

Publications and source records attributed to P Bonding.

At least 55 records · Page 3Linked to original sources
PubMed1983

Tympanosclerosis of the drum in secretory otitis after insertion of grommets. A prospective, comparative study.

In 193 consecutive children with bilateral secretory otitis, intubation and adenoidectomy were performed on the right ear and paracentesis on the left. Changes in the ear drum were analysed at re-evaluation one to three years after operation. In ears that had been intubated, tympanosclerosis occurred significantly more frequently (48 per cent) than in ears that had not been intubated (10 per cent). The frequency of atrophy of the pars tensa was the same. Of the right ears, 10 per cent were re-intubated, compared with 23 per cent of the left ears. The cause of the increased frequency of tympanosclerosis in the intubated ears must be mechanical, as decreased movements of the drum with inflammatory fibrous hyperplasia impede spontaneous normalization and promote hyalinization and calcification. The hearing was found to be similar in ears with and without tympanosclerosis.

Child↗
PubMed1981

Peritonsillar abscess.

In 161 patients treated for a peritonsillar abscess by stab incision as the only surgical procedure, a follow-up study was conducted after 3 1/2 to eight years. Of all the patients examined, 51% had experienced no throat symptoms, 22% had had recurrent peritonsillar abscesses, 20% had had recurrent episodes of tonsillitis with fever, and 7% had had symptoms resembling episodic pharyngitis in varying degrees. The age of the patient and the patient's history of previous throat infections were found to have prognostic value. Older patients (older than 40 years) had a lower incidence of new throat infections (peritonsillar abscess, tonsillitis, or both) than younger patients. Patients without previous throat symptoms had a lower incidence of new throat infections than patients with a history of throat infection before the peritonsillar abscess, which in itself might indicate the need for tonsillectomy.

Adolescent↗
PubMed1980

Loudness summation across frequency under masking and in sensorineural hearing loss.

The loudness summation across frequency was measured in unmasked and masked normally hearing subects, using noise bands centered at 1 kHz. Homolateral masking reduced the loudness summation of supracritical noise bands to a degree roughly proportional to the degree of threshold shift produced by the masking. Between thresholds and moderate sensation levels, the loudness summation increased at an invariable rate in the unmasked and the masked condition, reflected in an invariable supracritical growth of loudness with increasing stimulus bandwidth at identical sensation levels. At high intensities, the loudness summation decreased to roughly similar values in both conditions. Similar results were obtained by pooling the data from patients with sensorineural hearing losses and comparable threshold elevation. The critical bands appeared to be identical in unmasked and masked normally hearing subjects and in patients with sensorineural hearing losses. Contralateral, 35 dB effective masking produced a slight but consistent central masking effect; compared to the unmasked condition, the loudness summation of supracritical noise bands was reduced between threshold and medium stimulus levels, while it was increased at high levels.

Adolescent↗
PubMed1979

Treatment of postinflammatory acquired atresia of the external auditory canal.

In 11 patients postinflammatory acquired atresia of the auditory canal, 7-15 mm thick, was excised, the drum and auditory canal covered with a Thiersch graft alone or by fascia and a Thiersch graft. 2.5-5 years after the operation there was no case of recurrence of the atresia. The functional result was most favourable in cases with atresia of minor thickness. Early operation is recommended, especially as cholesteatoma was found behind the atresia in 2 patients.

Ear Canal↗
PubMed1979

Critical bandwidth in patients with acoustic neuroma.

Eleven patients with verified acoustic neuroma had critical band estimation performed by the method of loudness summation using noise bands centered around 1 kHz. The normal loudness difference between broad band noise and narrow band noise was reduced at all levels except the highest. Judged as single individuals, 9 of the 11 patients had a normal critical band. The pooled data indicated a normal critical band, both in patients with hearing loss less than 50 dB HL and in patients with hearing loss greater than or equal to 50 dB HL. The results are similar to those obtained in patients with Ménière's disease (Bonding, 1978c) and thus CB-measurements cannot be utilized for differentiating between cochlear and retrocochlear lesions. However, at the highest test levels applied the loudness difference between broad band noise and narrow band noise appeared to have some correlation to the presence or absence of recruitment.

Adult↗
PubMed1979

Critical bandwidth in presbycusis.

Twenty patients with presbycusis and a rather flat audiometric pattern had critical band estimation performed by the method of loudness summation, using noise bands centred around 1 kHz. The pooled data indicated a normal critical band both in patients with a hearing loss less than 50 dB HL and in patients with a hearing loss greater than or equal to 50 dB HL. The normal loudness difference between broad band and narrow band noise was reduced at all levels except the highest, giving rise to very flat CB functions. This reduction was more pronounced at the highest test levels in recruiting ears than in non-recruiting ears. A theory is suggested for parts of the anatomical and physiological correlate of the empirical phenomenon, the critical band.

Acoustic Stimulation↗
PubMed1979

Frequency selectivity and speech discrimination in sensorineural hearing loss.

Two supposed measures of auditory frequency selectivity--the critical band (CB) in loudness summation and the psychoacoustic tuning curve (PTC), Both measured at 1 kHz--were compared with the capacity for speech discrimination in patients with various cochlear disorders and a relatively flat audiometric pattern. The CB in loudness summation was correlated neither to the degree of hearing loss nor to the speech discrimination score. In contrast, the PTC changed with increasing hearing loss in the same manner as the electrophysiological tuning curve (FTC), i.e. rapidly deteriorating beyond normal limit values when the hearing loss exceeded 30--40 dB (HL). Nearly the same dependency of the degree of the hearing loss was demonstrated for the speech discrimination score (determined in noise and after filtering of the signal) and a significant correlation was present between this score and cochlear tuning, as expressed by the PTC. It is proposed that the PTC is a more valid measure of auditory frequency selectivity than the CB in loudness summation. If this is accepted the results seem to support the hypothesis of impaired frequency selectivity as a major cause for deteriorated speech discrimination in patients with cochlear disorders.

Hearing Loss, Sensorineural↗
PubMed1979

Critical bandwidth in loudness summation in sensorineural hearing loss.

Critical band estimation was performed in thirty-three patients with sensorineural hearing loss by the method of loudness summation, using noise bands centred around 1 kHZ. In 17 patients the hearing loss was of hereditary origin, in 16 patients of various, mostly unknown, origin. The normal loudness difference between broad band noise and narrow band noise decreased with increasing hearing loss, most pronounced in recruiting ears. Judged individually, 1/3 of the patients appeared to have a widened critical band, but several biases appeared to be responsible for these results. The pooled data indicated a normal critical band, both in patients with hearing losses less than 50 dB HL and in patients with hearing losses greater than or equal to 50 dB HL. Based on this finding, the validity of the critical band as a measure of the frequency selectivity of the ear is discussed and a theory is proposed for the anatomical and functional correlate of the critical band in loudness summation.

Adult↗
PubMed1978

Possible effects of kanamycin and incubation in newborn children with low birth weight.

In an acoustico-vestibular follow-up investigation of 91 four- to six-year-old children with birth weight below 2000 g, the same incidence of sensorineural hearing loss (19%) was found in 54 children treated with kanamycin in the neonatal period as in a group of 37 infants not treated with kanamycin. When comparing a group of children treated with both kanamycin and incubator (54 children) with a group treated with incubator only (16 children), no definite signs of synergism between incubator noise and kanamycin were found. However, the 5 cases of moderate or severe hearing loss all belonged to the group treated with both incubator and kanamycin. These 5 children had more severe neonatal complications, especially apnea, cyanotic spells and hyperbilirubinemia, which may increase the severity of the hearing loss. Among 56 incubator treated children with normal hearing (ISO standards) 52% had an audiogram pattern suggesting minor noise-provoked cochlear lesions. Among 18 non-incubator treated children with normal hearing only one child (6%) had a similar pattern. It should be stressed, however, that these children had no clinical symptoms of hearing loss.

Audiometry↗
PubMed1978

Loudness of complex sounds as a function of the standard stimulus and the number of components.

The purpose of this study was twofold: to determine if the measured loudness level of a signal depends on the standard stimulus used and to measure loudness as a function of the number of components in a wide-band signal. The stimuli were a pure tone, tone complexes with frequency separations of 231 and 1592 Hz, and noise bands with widths of 220 and 1592 Hz. The center frequency was 1 kHz and the loudness level was approximately 65 phons. Loudness matches between all combinations of stimuli showed that the measured loudness of the sounds did not depend on the standard stimulus used and the measured loudness level of a wide-band sound increased as a function of the number of components. Individual observers were consistent in their loudness estimations; the greatest source of variability was among subjects. Additional measurements indicated that the rate at which loudness increased beyond the critical band appeared to be greater for noise bands that for two-tone complexes.

Acoustic Stimulation↗
PubMed1978

Estimation of the critical bandwidth from loudness summation data.

An automatic method for critical band estimation from loudness summation data is presented. A mathematical model, based on a power function, is fitted to the data and the critical bandwidth is defined at the intersection of the asymptotes. The model is designed for clinical use, involving the treatment of the data from single test persons; it represents an operational solution to a difficult task. The model is able to describe data from normals and patients with a sensorineural hearing loss. Variability of the critical band estimates, intrasubject as well as intersubject, is larger than for visually obtained estimates. However, visual estimation is difficult, subjective, and probably heavily biased. The model produces estimates which in logarithmic form have a Normal distribution at medium loudness level, while visual estimation gives rise to irregular distributions at all levels. A normal range for model estimates from sets of data obtained at medium loudness level is defined by mean and standard deviation.

Auditory Perception↗
PubMed1978

Clinical critical band estimation.

A modified version of the method of loudness summation, developed for clinical critical band estimation, is presented. The stimuli are noise bands centred around 1 kHz. The standard procedure includes 1) determination of the "sensitivity curve": the loudness difference between broad band noise and narrow band noise as a function of the level. For clinical use this function is necessary for evaluation of the level with the most rapid growth of loudness with bandwidth, i.e. the optimum level for sharp determination of the critical bandwidth. 2) Determination of the critical band function, i.e. the difference in sound pressure level required for equal loudness of the test noise band and the reference as a function of the bandwidth. This determination is performed at a level with maximum growth of loudness, evaluated by the sensitivity curve. 3) Critical band estimation by a mathematical model, described in another work (Bonding et al., 1978) from the data obtained. The method is analysed regarding feasibility and reproducibility.

Adult↗
PubMed1976

Routine abscess tonsillectomy: late results.

The late results of abscess tonsillectomy as a routine treatment of peritonsillar abscess were investigated. The material comprises 113 patients. Follow-up was performed two to five years after the operation (bilateral dissection tonsillectomy under general anesthesia). Symptoms of pharyngitis, recurrent or chronic, were present in 17 percent of the patients, in most cases without major objective changes in the throat. The incidence of these symptoms was highest--70 percent--in patients past middle age without any history of trouble from the throat before the peritonsillar abscess. Tonsil remnants were seen in 28 percent, but only 6 percent of the patients had new episodes of febrile throat infections. The results are discussed. A reserved attitude to abscess tonsillectomy (and to interval tonsillectomy) is recommended for peritonsillar abscess in elderly patients without previous trouble from the throat.

Adolescent↗