Biomedical subjects

J Parbo

Publications and source records attributed to J Parbo.

7 recordsLinked to original sources

PubMed1990

Hearing disorders in patients with insulin-dependent diabetes mellitus.

The cochlear and retrocochlear hearing function was evaluated in patients with long- and short-term insulin-dependent diabetes mellitus (IDDM) by means of psychoacoustic testing and auditory brain stem responses (ABR). Twenty patients with diabetic microangiopathy (median age 41 years, range 25-66 years) were examined. The median duration of their diabetes was 26 years (range 13-46 years). In addition, 19 patients without microangiopathy (median age 27 years, range 17-42 years) and with a median duration of the diabetes of 2 years (range 0-6 years) were examined. The metabolic control estimated by blood glucose concentration and glycosylated haemoglobin was identical in the two groups of IDDM patients. After correction for age and sex, no significant differences in hearing thresholds or discrimination scores were present between the two diabetic groups, or between the diabetic patients and an age- and sex-matched normal background population. In the patients with long-term IDDM, ABR produced abnormal responses in 40%, indicating the presence of diabetic encephalopathy, whereas ABR were abnormal in only 5% of the patients with short-term IDDM.

Acoustic Impedance Tests↗

PubMed1989

Evoked acoustic emissions from the human ear. V. Developmental changes.

Twenty young children, in whom evoked acoustic emissions were recorded at birth, were re-examined at the age of 4 years. None of the children showed evidence of sensorineural hearing impairment and it was possible to record a reproducible emission in all ears, which displayed normal otoscopy and tympanometry (n = 9). The new recordings were compared with those obtained at birth and the latency and the amplitude of the response both appeared unchanged. However, in some ears the frequency content of the dominant part of the emission was considerably lower at the age of four. The implication of this finding is briefly discussed in view of recent data on cochlear development, obtained from animal research.

Child, Preschool↗

PubMed1988

Evoked acoustic emissions from the human ear. IV. Final results in 100 neonates.

Evoked acoustic emissions were recorded from both ears in a series of 100 consecutive normal newborns. We used the same stimulus, a 2-kHz click, and recording technique as previously described. Analysis of the data showed that evoked emissions could be identified in all ears, except one at 70 dBaud (i.e. approximately 30 dB nHL). No significant differences could be demonstrated between males and females or between left and right ears with regard to the latency of the emissions, the peak-to-peak amplitude, the main frequency component, or the waveform correlation between the two 70 dBaud recordings in each ear. However, a significant correlation between left and right ears was found for the amplitude and frequency of the emissions. Practical and methodological problems related to the recording were elucidated. The tail of the stimulus artifact sometimes interfered with the first part of the emissions even though the recordings were made in a time window delayed 5 ms relative to the stimulus onset. We tried to solve this artifact problem by different off-line techniques, but found no useful solution. We therefore continued to use only a cosine tapering of the first 2 ms of the time window. Three different ways of determining latencies were evaluated and we found that the 'envelope' technique was the most simple and reliable. Recording of evoked acoustic emissions is a quick and non-invasive method and provided that the presence of the emissions is related to normal cochlear function, it can be used as a screening test in newborns.(ABSTRACT TRUNCATED AT 250 WORDS)

Audiometry, Evoked Response↗

PubMed1987

Reference data for ABRs in retrocochlear diagnosis.

A retrospective analysis has been carried out on the auditory brainstem responses obtained in 235 female and 249 male neurologically normal patients. The analysis is focused on the wave latencies and the I-V and I-III intervals are compared with the classification parameters sex, age and high-frequency hearing loss. Since age and hearing loss are correlated, a multiple regression analysis is used to analyse the effects from the two variables. Both intervals are found to differ with sex (i.e. females display smaller values than males), to increase with age, and to decrease with hearing loss. Corrections are made for the classification parameters relative to 25 years and 0 dB HL. For the I-V interval, we find a mean value of 4.01 ms for the females and 4.19 ms for the males and a residual variance (SD) of 0.20 ms. For the I-III interval, we find a mean value of 2.13 ms for the females and 2.27 ms for the males and a residual variance (SD) of 0.16 ms. However, for the I-III interval, only the male data show dependence of hearing loss. In 78 patients, the electrocochleographic N1 is used to ensure the wave I latency and there is in general a good agreement between the two latency measures. However, in patients with profound high-frequency hearing loss differences up to 0.5 ms can be found.

Adult↗

PubMed1986

On prediction of hearing disability.

The present investigation was performed in order to evaluate the pure-tone frequency and/or averages of frequencies best correlated with speech intelligibility measured by the discrimination score (DS) in quiet and in background noise, and, in addition, indicate a valid low fence of the DS when correlated to a self-assessment procedure. The material comprises 158 male subjects with a median age of 60 years, range 52-72 years, drawn from an ongoing longitudinal epidemiological investigation. By self-assessment 36% indicated hearing disability in noisy backgrounds, while 64% had no hearing problems. The pure-tone frequency that correlated best with the speech intelligibility in quiet was the 2-kHz pure-tone frequency. In background noise the best correlation was found with the 3-kHz pure-tone frequency. In the group of subjects with complaints of hearing problems, the median discrimination score in background noise was 84% (IQR 72-92), while in the group of subjects with no complaints the median discrimination score in noise was 92% (IQR 88-96). Based on the results it is concluded that DS in background noise is a valuable measure in the assessment of hearing disability, but no low fence value can be indicated on the basis of the present results.

Aged↗

PubMed1986

Epidemiology of hearing impairment in male subjects: a follow-up investigation.

As part of a longitudinal study 158 male subjects, with a median age of 60 years, range 52-72 years, were re-examined after a 3-year interval. No significant deterioration in their hearing sensitivity was demonstrated when measured by pure-tone or speech audiometry. The prevalence of hearing impairment is 39% based on the criterion greater than or equal to 20 dB HL averaged over 0.5, 1, 2, 3, and 4 kHz. This is similar to the prevalence of 36% experiencing hearing problems in daily listening situations.

Aged↗

PubMed1985

Evoked acoustic emission: clinical application.

Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has only a minor effect on the power spectra, i.e. the maximum jumps from one spectral peak to another. Experiments with deconvolution demonstrate that the emission generating system at least at a fixed intensity can be regarded as being linear and characterized by its impulse response which is similar to the emission evoked by click stimuli. It is concluded that significant information is obtained by the click rather than by the tonal stimuli. The click-evoked emissions were also recorded from both ears in a consecutive series of 100 full-term and otherwise normal babies 2-4 days after birth. The emission amplitudes were of the same order of magnitude as those previously found in normal-hearing adults. Cross-correlation analysis was performed in order to evaluate reproducibility and the combination of amplitudes and correlation coefficients from supra-threshold recordings and the no-stimulus recordings reveals presence of a true emission from all ears tested. It is concluded that the cochlear echo can be recorded in normal-hearing newborns with an extremely low rate of type I errors.

Adult↗