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Biomedical subjects

W O Olsen

Publications and source records attributed to W O Olsen.

At least 19 recordsLinked to original sources
PubMed1990

Preoperative and postoperative auditory brain-stem response results for patients with eighth-nerve tumors.

Preoperative and postoperative auditory brain-stem response results and audiologic data were reviewed for seven patients whose hearing was preserved after eighth-nerve tumor surgery. Auditory brain-stem response absolute latencies (I, III, and V) and interpeak intervals (I-III, III-V, and I-V) were identified more often postoperatively than preoperatively. Even though postoperative absolute latencies were usually abnormal, the interpeak intervals were usually normal following surgery. Postoperative hearing sensitivity was unchanged or slightly poorer for five of the seven patients, but postoperative speech discrimination was the same or better for six of the seven patients. All three patients having acoustic reflex testing showed improvement postoperatively.

Adult↗
PubMed1990

Comparison of ABR amplitudes with TIPtrode and mastoid electrodes.

ABR evaluations were completed for 36 adults (18 males, 18 females) having normal hearing sensitivity and for 91 adult patients having various degrees of sensorineural hearing loss. Amplitudes of waves I and V were compared for ear canal (TIPtrode) electrode and mastoid electrode recordings. Interpeak intervals (I-III, III-V, and I-V) were determined and upper 95% confidence limits defined for normative data. In general, amplitude of wave I was larger when TIPtrodes were used. Wave V amplitude was nearly identical for the two electrodes. Wave I was identified more frequently for TIPtrode than for mastoid recordings of ABR waveforms for the sensorineural hearing loss subjects.

Acoustics↗
PubMed1989

Wave V interaural latency differences as a function of asymmetry in 2,000-4,000 Hz hearing sensitivity.

Interaural latency differences for wave V (IT5) were measured for 406 patients having cochlear hearing loss and for 36 patients with VIIIth nerve tumors. The incidence of IT5 values exceeding 0.2, 0.3, and 0.4 msec was plotted as a function of the degree of asymmetry in hearing sensitivity for 2,000-4,000 Hz. In general, the patients with cochlear hearing loss and the greatest degree of hearing asymmetry yielded IT5 values that exceeded 0.2, 0.3, or 0.4 msec more frequently than patients with more symmetric hearing losses, and this trend was apparent for all degrees of hearing loss. For the VIIIth nerve tumor patients, IT5 data were scattered widely regardless of symmetry or asymmetry of hearing sensitivity. The false-negative rate was 8% when IT5 was greater than 0.4 msec.

Adult↗
PubMed1988

Auditory brainstem responses as a function of average hearing sensitivity for 2,000-4,000 Hz.

Average hearing thresholds for 2,000, 3,000 and 4,000 Hz and ABR results were analyzed for 290 patients having some degree of cochlear hearing loss. As average hearing sensitivity in the 2,000- to 4,000-Hz range became poorer, the incidence of abnormal auditory brainstem responses (ABR) increased. When the 2,000-Hz threshold sensitivity was 0-40 dB and the three-frequency average hearing loss was less than 50 dB, nearly 80% of ABR tracings were normal. Steeply sloping audiograms above 2,000 Hz increased the percent of abnormal ABR results.

Auditory Threshold↗
PubMed1987

Brief tone audiometry: a review.

This paper reviews a number of studies on temporal integration of acoustic power at threshold. A wide variety of results for normal-hearing individuals and for hearing-impaired patients is revealed. This variability limits the current clinical application of brief tone audiometry.

Audiometry↗
PubMed1987

Representations of the long-term spectra of speech.

Numerous and somewhat different representations of the long-term spectra of speech are available in the literature. Various estimates of speech spectra have been converted to a consistent audiogram format for presentation here. Even so, plots of speech spectral levels across the frequency region of 125 to 8000 Hz vary considerably. Bases for some of these variations and clinical utilization of a speech spectrum are discussed.

Auditory Threshold↗
PubMed1986

The effect of 2000-4000 Hz hearing sensitivity on ABR results.

Pure-tone hearing sensitivity at 2000, 3000, and 4000 Hz and ABR results were reviewed for 458 patients with cochlear hearing loss. Wave V latency and waveform morphology data from the 916 ears yielded percentages of abnormal ABR results as a function of degree and slope of hearing loss. Threshold sensitivity at all three frequencies influenced ABR latency or waveform. A higher incidence of abnormal ABR results was observed when 3000 Hz thresholds were elevated than when 4000 Hz thresholds were elevated to the same levels. ABR results for various audiometric configurations are reported.

Adult↗
PubMed1979

Bone conduction calibration: current status.

Attempts to specify normal threshold sensitivity by bone conduction have been unsuccessful because of problems in obtaining reliable measurements from commercially available artificial mastoids. Recent design modifications incorporated in the Bruel and Kjaer 4930 artificial mastoids have resulted in greater uniformity among these units. However, the new design has resulted in impedances that are higher than those recommended in current standards. Bone-conduction thresholds referenced to measurements made on B & K 4930 artificial mastoids with the new design were performed on 60 normal listeners by three participating laboratories. The results are reported for consideration in the development of a reference threshold for hearing by bone conduction.

Acoustic Impedance Tests↗
PubMed1978

Signal monitor for audiometry.

Conventional volume unit (VU) and auditory monitors of signals generated by or fed through an audiometer do not allow monitoring of the signal after the attenuator or output selector. An amplifier-compressor circuit has been designed and constructed which allows auditory monitoring of the electrical signal at the transducer. The circuit and its use are described.

Amplifiers, Electronic↗
PubMed1975

Bekesy test results in patients with eighth-nerve lesions. Forward reverse- and fixed-frequency tracings.

Sweep-frequency Bekesy tracings, both forward (low to high frequency) and reverse (high to low frequency), as well as fixed-frequency tracings, were obtained from 18 patients who had eighth-nerve tumors (subsequently confirmed surgically). In general, reverse-sweep frequency tracings revealed greater adaptation for continuous tone stimuli than did forward-sweep frequency tracings. However, if a search for excess adaptation (greater than 20 dB) is the sole purpose for administering Bekesy audiometry to a given patient, then fixed-frequency tracings yield adequate differential information.

Adaptation, Physiological↗
PubMed1975

Acoustic reflex and reflex decay. Occurrence in patients with cochlear and eighth nerve lesions.

Acoustic reflex and reflex decay tests were administered to 50 normal ears, 50 ears with hearing loss due to noise trauma, 50 ears that had Meniere disease, and 28 ears that had involvement of the eighth nerve. In one normal ear, ten noise trauma ears, 11 Meniere disease ears, and 24 eighth nerve lesion ears to reflexes or reflex decay that were suggestive or retrocochlear lesions were observed. Acoustic reflex and reflex decay results are also compared to tone decay results for these patients.

Acoustic Stimulation↗
PubMed1975

Heredopathia atactica polyneuritiformis (phytanic acid storage disease). A new case with special reference to dietary treatment.

A 33-year-old man with Refsum disease exhibited clinical features of night blindness, dysequilibrium, hearing loss, itchy dry skin, symmetrical polyneuropathy, distal muscle weakness, pes cavus, and hammer toe. His total serum protein was increased, nerve conduction velocities were slow, and serum phytanic acid levels were high. Dietary restriction of phytol resulted in a decrease in serum phytanic acid without any visual and autitory changes; however, coordination, skin lesions, and nerve conduction velocities definitely improved.

Adult↗