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S Okstad

Publications and source records attributed to S Okstad.

6 recordsLinked to original sources
PubMed1988

High-frequency audiometry: air- and electric bone-conduction.

Normative values have been obtained for high-frequency air- and electric bone-conduction thresholds in different age groups. Reproducibility with both methods is of the same order of magnitude as with conventional audiometry. The two thresholds can be compared and the air-conduction/electric bone-conduction gap obtained by transforming the electric bone-conduction values to a dB notation by means of a formula containing a frequency-dependent constant.

Adult↗
PubMed1988

High-frequency audiometry: comparison of electric bone-conduction and air-conduction thresholds.

Thresholds have been measured with two commercially available high-frequency (HF) audiometers providing respectively air-conduction (AC) and electric bone-conduction (EBC) stimulation. Normative values for the latter have been obtained, and the reduction of HF sensitivity with both stimulus modes documented in two groups aged 50-59 and 70-79 years. EBC reproducibility is of the same order of magnitude as the AC signal through 14 kHz, while the dynamic range is limited to 50 dB. Lateralization of the EBC signal occurs up to at least 17 kHz. The logarithmic conversion factor of Tonndorf and Kurman [Ann. Otol. Rhinol. Lar. 93: 576-582, 1984] does not result in equivalent AC and EBC thresholds at all frequencies, but does provide similar loudness sensation increases. The 40 log (i) re 1 mA conversion factor must be adjusted with a frequency-dependent additive correction.

Adult↗
PubMed1988

Screening for retrocochlear pathology.

In 1982, 135 patients were screened for possible retrocochlear pathology, by means of an investigation protocol consisting of caloric test, impedance audiometry and brainstem response audiometry (BRA). A combination of the first two of these procedures had an unacceptably low prognostic accuracy. BRA indicated retrocochlear pathology in 8 and was inconclusive in 4 cases. Enhanced computer tomography revealed an intracranial tumour in 4 of the former, while no space-occupying lesion could be demonstrated in the remainder nor in the 4 patients with inconclusive BRA. BRA is the best single test for screening of this patient category.

Acoustic Impedance Tests↗
PubMed1986

Ectopic thyroid tissue in the head and neck.

A review has been performed of thyroid ectopia seen during a 10 year period. There were five cases of total ectopia; three of these were lingual thyroids, one situated in the perihyoid region had been clinically diagnosed as a thyroglossal cyst, while the fifth presented as a tumor in the lateral neck. In the same period 41 thyroglossal cysts were removed. None of these showed uptake on technetium scintigraphy. Thyroid tissue was present in the cyst walls in 41% of cases. Scintigraphy should be performed routinely if the clinical picture is at all compatible with thyroid ectopia.

Adult↗