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Biomedical subjects

J Jerger

Publications and source records attributed to J Jerger.

At least 109 records · Page 6Linked to original sources

A new acoustic reflex pattern.

A new crossed-vs-uncrossed acoustic reflex pattern has been observed in four patients with retrocochlear disorder. The new reflex pattern is characterized by a unique "uni-box" configuration. Reflexes are abnormal with sound to the affected ear on crossed stimulation only. In one additional patient, a variation of the uni-box pattern was found on suprathreshold reflex amplitude measures. WE observed a large ear difference between reflex amplitude functions in the crossed condition, but not in the uncrossed condition. This observation suggests that reflex amplitude measures may be a valuable addition to threshold measures in some patients.

Adolescent↗

Auditory brain stem evoked responses to bone-conducted signals.

Auditory brain stem evoked responses to air-conducted and bone-conducted signals were recorded in subjects with normal hearing and in subjects with conductive hearing loss. In normal subjects, the latency to wave V for bone-conducted signals was approximately 0.5 ms longer than the latency for air-conducted signals delivered at the same sensation level. In conductive hearing loss, the separation of the latency-intensity functions for air conduction and bone conduction (corrected for the 0.5-ms delay) provided a valid estimate of the behavioral air-bone gap in the 1,000- to 4,000-Hz region.

Audiometry, Evoked Response↗

Aging and the use of hearing aids.

Elderly subjects with both peripheral and central auditory deficits perform less well with amplification than elderly subjects with peripheral deficits only. This decrease in aided performance remains after control for degree of sensitivity loss, absolute speech understanding score, and chronological age. Furthermore, females show greater central deficits and, consequently poorer aided performance, than males. We discuss the implications of these findings for the auditory rehabilitation of the elderly.

Aged↗

Response detection in respiration audiometry.

The respiration of ten adults with normal hearing was monitored to determine how well changes in respiration could be detected after auditory stimulation. Three judges used two methods of response scoring. The first was without knowledge of signal presentation, and the second was with knowledge of signal presentation. Judges detected the presence of respiratory responses not only during signal presentations (hits) but also during silent intervals (false alarms). Hits and false alarms co-varied in a manner predicted by the theory of signal detectability. A low false alarm rate could be purchased only at the expense of a low hit rate. The implications of this finding for the clinical efficacy of respiration audiometry are considered.

Acoustic Stimulation↗

Impedance audiometry in the squirrel monkey. Effect of middle ear surgery.

The two principal components of impedance audiometry, the tympanogram and acoustic reflexes, were measured preoperatively and postoperatively in seven squirrel monkeys subjected to experimental middle ear surgery. A probe-tone frequency of 1,200 Hz yielded both tympanograms and acoustic reflex thresholds roughly comparable to analogous data in humans at a probe-tone frequency of 220 Hz. Both tympanograms and acoustic reflex thresholds could be obtained reliably and with comparative ease. In general, postoperative data were modified in the expected fashion by the experimental middle ear surgery. Impedance audiometry appears to be a worthwhile and useful technique for monitoring middle ear status in the squirrel monkey.

Acoustic Impedance Tests↗

Effect of age on prediction of sensorineural hearing level from the acoustic reflex.

To study the effect of age on prediction of hearing level from the acoustic reflex, we compared reflex prediction with the actual hearing level in 505 patients. The following three age groups were defined: 130 children aged 2 to 12 years; 158 young adults aged 20 to 40 years; and 217 old adults aged 60 to 90 years. Prediction was substantially more accurate in the children's group than in either adult group.

Acoustic Stimulation↗

Prediction of sensorineural hearing level from the brain stem evoked response.

Correlational analysis was carried out between the auditory brain stem evoked response (BER) threshold, BER latency, and various audiometric indices in 275 ears with varying degrees and configurations of sensorineural hearing loss. Results confirm the importance of sensitivity in the 1 to 4-kHZ region to the brain stem response. Sensitivity over this frequency region is best predicted as 0.6 of the BER threshold. Brain stem evoked response latency in the 70- to 90-dB hearing level range increases about 0.2 ms for each 30-dB increase in the steepness of the audiometric contour between 1 and 4 kHZ. Finally, audiometric shape appears to be more important than absolute high-frequency sensitivity in determining BER latency.

Adolescent↗

Impedance audiometry in the squirrel monkey. Sensorineural losses.

Acoustic reflex thresholds for pure tones and broad-band noise were measured before and after treatment of nine squirrel monkeys. Experimental sensorineural hearing loss was created in six monkeys by ototoxic drug administration (gentamicin) and in three monkeys by exposure to intense sound. Extent of cochlear damage was assessed histopathologically, in the case of permanent loss induced by the ototoxic agent, and inferred from exposure history, in the case of the reversible loss induced by exposure to intense sound. Posttreatment changes in relationships among acoustic reflex thresholds (noise-tone difference [NTD]) reflected approximate degree of cochlear damage. Serial measurement of changes in the NTD in acoustic reflex thresholds appears to be a worthwhile and useful technique for monitoring sensorineural levels in the squirrel monkey.

Acoustic Impedance Tests↗

Central auditory function in stutterers.

Central auditory function was assessed in 10 stutterers and 10 nonstutterers. Performance of the two groups was compared for seven audiometric procedures including acoustic reflex threshold, acoustic reflex amplitude function, performance intensity function for monosyllabic phonetically balanced (PB) words, performance intensity function for Synthetic Sentence Identification, Synthetic Sentence Identification with Ipsilateral Competing Message, Synthetic Sentence Identification with Contralateral Competing Message, and the Staggered Spondaic Word test. Relative to the control group, the performance of the stuttering group was depressed on three procedures--the acoustic reflex amplitude function, Synthetic Identification with Ipsilateral Competing Message, and Staggered Spondaic Word test. As a group, the stutterers presented evidence of a central auditory deficiency. The pattern of test results suggests a disorder at the brainstem level. The subtlety of the deficiency is emphasized.

Acoustic Impedance Tests↗

Comparative toxicity of netilmicin and gentamicin in squirrel monkeys (Saimiri sciureus).

Netilmicin was found to be less toxic than gentamicin when administered at comparable dosage levels to squirrel monkeys (Saimiri sciureus). This finding is based upon data obtained from the following determinations: length of survival period; change in body weight; observation of general change in behavior after daily injection; ataxia, as measured by the squirrel monkey platform-runway test; acoustic reflex threshold; levels of blood urea nitrogen and serum creatinine (and pathology of the kidney); and microbiological antibiotic assay.

Acute Disease↗

Diagnostic speech audiometry.

The scope of speech audiometry can be expanded to provide useful diagnostic information. Comparison of performance vs intensity (Pl) functions for both phonemically balanced (PB) words and synthetic sentence identification (SSl) yields pattersn useful in differentiating among peripheral and central sites of auditory disorder.

Adolescent↗

Diagnostic value of crossed vs uncrossed acoustic reflexes: eighth nerve and brain stem disorders.

Acoustic reflexes to crossed (sound in one ear; probe in opposite ear) and uncrossed (sound and probe in the same ear) stimulation were obtained from 17 patients with eighth nerve or brain stem disorders and 20 normal control subjects. Comparison of crossed and uncrossed reflex thresholds provided an important diagnostic tool for differentiating the eighth nerve from the brain stem site. Egihth nerve disorders were usually characterized by diagonal reflex patterns. In contrast, brain stem disorders were usually characterized by horizontal reflex patterns. Detailed evaluation of the reflex time course in two selected patients with intra-axial brain stem disorder showed unusual abnormalities in the crossed acoustic reflex.

Acoustic Stimulation↗

Hearing aid evaluation. Clinical experience with a new philosophy.

We report a new method of hearing aid evaluation with the underlying philosophy that evaluation of hearing aid performance is not an end in itself, but an integral part of the total rehabilitation of the hearing-impaired patient. This new method uses synthetic sentences and speech competition in varying "message-to-competition ratios (MCRs)" to evaluate patient performance with hearing aids. We report six illustrative cases and a follow-up survey of patient satisfaction with recommended hearing aids to relate our experience with this technique.

Adult↗

Acoustic reflex characteristics in spastic dysphonia.

Acoustic reflex characteristics were studied in six persons with spastic dysphonia. Two methods of analysis were used: (1) a double-blind qualitative judgment of acoustic reflex recordings, and (2) a quantitative analysis of specific temporal characteristics of the acoustic reflexes. Judgments of reflex recordings did not reliably differentiate spastic dysphonia subjects from controls. An analysis of five latency measures revealed a difference between groups only in one measure, reflex contraction time.

Acoustic Stimulation↗