Biomedical subjects

L M Bergholtz

Publications and source records attributed to L M Bergholtz.

10 recordsLinked to original sources

PubMed1987

Audiological and vestibulo-oculomotor findings in workers exposed to solvents and jet fuel.

Three groups of subjects with long-term (5-41 years) occupational exposure to industrial solvents have been evaluated with extensive audiological and vestibular test batteries. Group A comprised 16 subjects with a confirmed diagnosis of psycho-organic syndrome (POS), while group B consisted of 7 subjects with suspected POS. Both groups had been exposed to mixtures of aliphatic and aromatic solvents. Eight subjects with long-term exposure to jet fuel constituted group C. In the audiological test battery, discrimination of interrupted speech and evoked cortical potentials in response to frequency glides were the tests that yielded significantly abnormal results. In the vestibular test battery, considerable pathology was seen in electronystagmography, and in addition, visual suppression test and saccade test indicated CNS disturbance. In general, when a test yielded pathological results, the incidence of pathology was highest in group A and lowest in group C.

Adult↗

PubMed1983

Otoscopy compared with tympanometry.

A study comparing otoscopy with tympanometry was carried out in 1702 ears in seven- and ten-year-old children. Pneumatic otoscopy in 917 ears showed an 88 per cent agreement with tympanometry. The agreement was better in ears considered normal by the otoscopist than in ears that were considered abnormal. Furthermore, the accuracy of otoscopy was better in the older children than in the younger ones. A procedure employing simple otoscopy in 785 ears gave an 83 per cent agreement, but in about 15 per cent of these ears the examiner felt unable to base his evaluation on certainty. It was found that a middle-ear pressure of -100 mm. H2O correlated with recognizable pathology when pneumatic otoscopy was performed.

Acoustic Impedance Tests↗

PubMed1983

Audiologic screening of seven- and ten-year-old children.

An audiologic screening of 1 062 ears In 7-year-old and 1 175 ears in 10-year-old children was carried out by means of pure-tone audiometry and tympanometry. New cases of sensorineural hearing loss were found in six ears (0.3%). The prevalence of protracted undiagnosed middle ear pathology was found to be 2.5 and 0.5%, in the younger vs. the older age group respectively. It is concluded that a middle ear pressure more negative than -250 mmH2O would be a suitable fail criterion for tympanometry. It is questionable, however, whether tympanometric mass screening of 7- and 10-year-olds is meaningful. It is felt that pure-tone audiometry maintains its position in the screening role.

Acoustic Impedance Tests↗

PubMed1983

Audiological screening of school children--preliminary results.

An audiological screening of 1120 school children aged seven and ten revealed abnormal tympanograms in 11% of the ears. In the younger children the failure rate was twice as high as in the older. Follow-up examinations showed, however, that only about three per cent of the ears screened displayed pathological middle ear pressure after 8-16 weeks. In the light of this the cost-effectiveness of screening tympanometry can be questioned. Pathological pure tone audiograms were found in 0.5% of the ears with normal middle ear pressure.

Acoustic Impedance Tests↗

PubMed1977

Electrocochleographic response patterns in a group of patients mainly with presbyacusis.

The latency, amplitude and wave-form of the action potential were studied in a group of patients, mainly presbyacusics and a few with noise-induced hearing loss, sensorineural hearing loss of unknown etiology and conductive loss. Electrocochleographic recruitment with short latency of the AP "threshold" and very rapid increase in amplitude with increasing click intensity was seen in 22%. Partial recruitment with long latency at AP "threshold" but steep amplitude-intensity curves was present in 33%. Only 17% of the subjects showed both electrocpchleographic recruitment (or partial recruitment) and recruitment in the acoustic reflex test. Subjects with conductive loss had normal amplitude and latency intensity curves but they were shifted to the right. The action potential wave-form was normal. Broad action potentials with multiple peaks were the most common in sensorineural hearing loss.

Action Potentials↗

PubMed1977

Electrocochleography: a comparison of action potential and behavioral thresholds.

Using the technique of electrocochleography with transtympanic electrode placement, it is possible to estimate behavioral thresholds from AP data for a acoustic stimulus. The correlation between behavioril and AP "thresholds" for the same stimulus was statistically significant and there was a better correlation for subjects with a mild hearing loss than for those with normal hearing or larger degrees of hearing loss (as determined by the pure tone average). Larger amplitudes of the AP at the maximum stimulus level tended to be associated with a more accurate threshold estimation. The AP "thresholds" showed best correlation with the pure tone audiometric thresholds at 1 000 Hz, at other tone frequencies the correlation was poorer. This agrees with the spectral contents of the click.

Action Potentials↗

PubMedDate not supplied

Test-retest reliability in clinical electrocochleography.

The intratest test-retest reliability in clinical electrocochleography was studied by measuring the difference between amplitude of the test and retest and latency of the test and retest. Eighty-four comparisons were made in 40 patients with different types of hearing losses. The type of hearing loss and whether test and retest were performed in sequence or not did not affect the variability of the amplitude. The test and retest correlation between amplitudes was good. Small amplitudes mainly found near the action potential (AP) "threshold" showed less absolute variability than larger amplitudes found at higher intensities. The correlation between the intratest latencies was excellent. The latency showed less variability at higher intensities than near AP "threshold".

Action Potentials↗

PubMedDate not supplied

Electrocochleography used as a clinical hearing test in difficult-to-test children.

Thirty difficult-to-test children have been tested with transtympanic ECoG. When possible, informal hearing tests and/or free-field testing were performed. Children in whom no action potential (AP) could be recorded were submitted to conventional radiography of the inner ear, and vestibular tests. The correlation between free-field test thresholds and AP "thresholds" was good, especially in subjects with relatively good hearing. Response amplitude increased, and latency decreased, with increasing frequency of the stimulus implying that different parts of the basilar membrane are stimulated according to the frequency of the stimulus. Input-output curves of response amplitude and latency were plotted, and three different types were distinguished. ECoG can contribute to the evaluation of peripheral hearing in difficult-to-test children, and vestibular tests should always be performed on a child with suspected deafness or sensorineural hearing loss. Conventional radiography of the inner ear, however, seems to be of little value.

Action Potentials↗

PubMedDate not supplied

Peroperative temporary threshold shift in ear surgery. An electrocochleographic study.

TTS resulting from drilling in the temporal bone was detected by means of pre- and post-exposure ECoG recordings taken during ear surgery for chronic otitis media. The TTS obtained varied between 5 and 40 dB at 4 and 8 kHz. The correlation between duration of noise exposure and magnitude of TTS was statistically significant. The results indicate that drill-induced noise in ear surgery may result in postoperative high-tone sensorineural hearing loss, and support the view that manipulation of the ossicular chain during ear surgery causes mainly a threshold shift at the lower frequencies.

Acoustic Stimulation↗

PubMedDate not supplied

Otoneurological findings in psycho-organic syndrome caused by industrial solvent exposure.

Nine subjects with long-term (8-30 years) occupational exposure to industrial solvents and a confirmed diagnosis of psycho-organic syndrome (POS) have been studied with audiological and otoneurological test batteries. The results were compared to a matched control group of nine industrial workers not exposed to solvents and to normal data from healthy volunteers. In the clinical examination, the Romberg test identified 5/9 workers as pathologic and concurrently the stabilometry showed significantly larger sway areas in the POS-group. In the audiological test battery, the significantly pathologic tests were discrimination of interrupted speech and evoked cortical responses to frequency glides (CRA-delta-f). The saccade test disclosed abnormal findings in 5/9 workers. In the smooth pursuit test, abnormality was found at some test frequencies using pseudorandomized stimulus. The VOR-suppression test was significantly abnormal at all test frequencies. The test battery used strongly indicates CNS lesions due to industrial solvents.

Adult↗