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Biomedical subjects

J Jerger

Publications and source records attributed to J Jerger.

At least 19 recordsLinked to original sources
PubMed1992

Age-related asymmetry on a cued-listening task.

We report results on a cued-listening task designed to simulate the listening problems commonly described by individuals with sensorineural hearing loss, especially those experienced by elderly persons. Against a background of multitalker babble, the subject detected targets embedded in continuous discourse. Noncoherent segments of this discourse were presented simultaneously from loudspeakers on the right and left sides. A signal light cued the side to be monitored during a listening trial. The overall difficulty of the task was manipulated by variation of the message to competition intensity ratio. A sequence of listening trials, half-cued to the right side, half cued to the left side, was executed at each of four message to competition intensity ratios. Nineteen young adults with normal hearing and 28 elderly persons with presbyacusic hearing loss were evaluated. All subjects, young and elderly, were able to complete the cued-listening task successfully. Results showed a small but significant right-side advantage in the young group and a substantial right-side advantage in the elderly group. The application of the testing technique to the evaluation of hearing aid performance is illustrated in two elderly persons.

Adult↗
PubMed1992

Acoustic reflex abnormalities in cranial-cervical dystonia.

Previous anatomic and physiologic studies suggest brainstem dysfunction in cranial-cervical dystonia. To further explore this, we studied suprathreshold acoustic reflex waveforms in 15 such patients. A unique feature of this technique is its ability to reject movement artifacts before averaging the acoustic reflex waveforms. Thirteen patients (87%) showed some abnormality in reflex waveform morphology. There were both amplitude and latency abnormalities. These findings support the hypothesis that cranial-cervical dystonia reflects dysfunction of the brainstem.

Acoustic Stimulation↗
PubMed1992

Phase coherence of the middle-latency response in the elderly.

We compared phase coherence of the auditory-evoked, middle-latency response (MLR) and the 40-Hz steady-state evoked potential (SSEP) in two groups of elderly listeners, matched for degree of audiometric hearing sensitivity loss. In group A, speech understanding was appropriate to the degree of audiometric sensitivity loss. In group B, speech understanding was disproportionately poor in relation to the degree of loss. In both modes of measurement (MLR and SSEP) phase coherence was significantly poorer in group B than in group A. In the case of MLR, maximum phase coherence was observed at the expected 40 Hz in group A, but at 30 Hz in group B. In the case of SSEP, maximum phase coherence was observed at 40 Hz in both groups but was poorer at almost all Fourier components in group B.

Acoustic Stimulation↗
PubMed1992

Otoacoustic emissions, audiometric sensitivity loss, and speech understanding: a case study.

The clinical measurement of otoacoustic emissions can assist in differentiating between peripheral and central explanations for deficits in speech understanding. We present audiometric and distortion-product emission data in a case with sensorineural hearing loss and a deficit in speech understanding. The presence of evoked emissions argues against attributing the speech audiometric loss to cochlear defect.

Adult↗
PubMed1992

Can age-related decline in speech understanding be explained by peripheral hearing loss?

Speech audiometric scores were compared across the age range from 50 to 90 years in 137 subjects selected in such a way that average audiometric thresholds were matched across four age groups. Thus any age-related changes in speech audiometric scores could not be attributed to age-related differences in peripheral hearing sensitivity. Four speech audiometric measures were studied; phonemically-balanced words (PB), Speech Perception in Noise (SPIN) test for both high- and low-predictability sentences, and the Synthetic Sentence Identification (SSI) test. There was an age trend for all four speech measures but only the change in SSI (30%) was statistically significant. The argument that the change in SSI can be explained by subtle changes in the auditory periphery, not reflected in audiometric thresholds, is weakened by the fact that the change in SSI was greater than the change in either of the two monosyllabic word tests (PB and SPIN-low). The argument that the change in SSI can be explained by concomitant cognitive decline is not supported by correlations among SSI performance and any of several neuropsychological measures of cognitive function in the same subjects. Finally, the lack of a significant interactive effect between hearing sensitivity level and cognitive status does not support a model in which a peripherally degraded speech signal interacts with a deficit in cognitive function to produce the decline in speech audiometric scores. We conclude that the observed age-related decline in SSI performance cannot be satisfactorily explained by peripheral hearing sensitivity loss.

Aged↗
PubMed1979

Low-frequency hearing loss in presbycusis. A central interpretation.

Elderly subjects with a central phonemically balanced (PB) and synthetic sentence identification (SSI) pattern show greater low-frequency (LF) sensitivity loss than elderly subjects with a peripheral PB-SSI pattern. This LF hearing loss is not the simple consequence of age, nor does the LF hearing loss account for depressed SSI performance. We conclude that LF sensitivity loss and a central PB-SSI pattern are both components of central aging. We discuss the implications for auditory rehabilitation of elderly subjects.

Aged↗
PubMed1979

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↗
PubMed1979

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↗
PubMed1979

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↗
PubMed1978

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↗
PubMed1978

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↗
PubMed1978

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↗
PubMed1978

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↗
PubMed1978

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↗
PubMed1978

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↗
PubMed1978

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↗