Psychophysical measurements of inner ear processes with category scaling of loudness.
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Audiometry↗
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Results for “Loudness Perception”
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Carbamazepine in the treatment of Lyme disease-induced hyperacusis.
Lyme disease-induced hyperacusis can be an intensely disabling, chronic condition that is accompanied by posttraumatic stress disorder-like psychobehavioral sequelae. The authors describe effective treatment of 2 patients with carbamazepine. Speculations regarding a mode of action are offered.
Adult↗
Effects of Clarion electrode design on mapping levels in children.
The design of the placement of the Clarion cochlear implant's intracochlear electrode array has undergone 2 revisions since its introduction, each to improve modiolar proximity. Stimulation with modiolar proximity may reduce current requirements for threshold levels and most comfortable levels of stimulation. This study analyzed the effects of electrode design on programming levels for deaf children implanted with the 3 cochlear implant designs and followed at The Children's Hospital of Philadelphia. Psychophysical data were reported if measurements were taken approximately 3 months after initial activation, and programming parameters included nonsequential monopolar stimulation of 75-micros-per-phase biphasic pulses presented at 813 Hz per electrode. The threshold level and most comfortable programming level were measured by standard clinical techniques appropriate for children. The results indicate that the 2 electrode placement revisions have each significantly reduced threshold levels and most comfortable stimulation levels. These results are discussed in the context of device aesthetics, safety, and function.
Acoustic Impedance Tests↗
Optimizing cochlear implant speech performance.
Results of studies performed in our laboratory suggest that cochlear implant recipients understand speech best if the following speech processor parameters are individually chosen for each person: minimum and maximum stimulation levels on each electrode in the speech processor program (MAP), stimulation rate, and speech coding strategy. If these and related parameters are chosen to make soft sounds (from approximately 100 to 6,000 Hz) audible at as close to 20 dB hearing level as possible and loud sounds not too loud, recipients have the opportunity to hear speech in everyday life situations that are of key importance to children who are learning language and to all recipients in terms of ease of communication.
Auditory Threshold↗
Growth of loudness for sinusoidal and pulsatile electrical stimulation.
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Cochlea↗
Recent advances in hearing aid selection and adjustment.
Recent research has shown that speech is most intelligible for hearing-impaired individuals when it is amplified to a comfortable level in specific frequency regions between 250 and 6,000 Hz, and is limited below the discomfort level. If commercial hearing aids and earmold coupling are adjusted appropriately, they will provide amplified sound within these parameters for most hearing-impaired individuals. A clinical procedure is described 1) to preselect an aid and earmold with the approximate electroacoustic characteristics that are needed, 2) to determine the gain actually provided by this hearing aid/earmold combination, and 3) to adjust the hearing aid and/or earmold if the gain and maximum output do not meet the prescribed criteria, or if the wearer finds the sound quality unacceptable.
Acoustics↗
Reimplantation of a molded scala tympani electrode: impact on psychophysical and speech discrimination abilities.
Revision surgery was successfully performed on two Vienna cochlear implant patients. Twenty months and 40 months, respectively, after initial insertion into the cochleas of two bilaterally deaf patients, electrodes were removed from the scala tympanis and replaced by electrodes of the same design. Psychophysical and speech data gathered before and after the revision surgery were compared. These were thresholds, loudness scalings, amplitude difference limens, pitch scalings, frequency difference limens, and speech tests in the "stimulation only" modality. No negative changes were found. The data available demonstrate a continuous improvement in performance over many months of practice with the sound processor. This development was not impeded by the revision surgery. Thus, it was demonstrated that the removal and replacement of a molded scala tympani electrode is feasible.
Adult↗
The acoustic startle response and disruption of aiming: I. Effect of stimulus repetition, intensity, and intensity changes.
Three experiments examined the disruption of perceptual motor performance by intense noise bursts. Subjects aimed a rifle at a fixed target for 15-s periods separated by 15 s of rest. This cycle was repeated 30 times in each of two series separated by a 15-min rest, each series containing five noise bursts. The noise bursts disrupted aiming for 1-2 s, an effect that increased with sound pressure level for 110, 120, and 130 dB stimuli. There was no difference between stimuli with energy centered on 250 Hz as opposed to 800 Hz. The effect diminished over the five bursts within the first series (but not to zero) and did not recover in the 15-min rest period. Some subjects received three days of testing; in these cases the effect of the noise bursts partially recovered after rest intervals of 24 hrs and then seven days. Other subjects received 15 trials with 110-dB stimuli, then five more trials with 130-dB stimuli. The disruption of aiming by 130 dB stimuli was not reduced by prior exposure to 110-dB stimuli.
Adult↗
The acoustic startle response and disruption of aiming: II. Modulation by forewarning and preliminary stimuli.
Four experiments examined the disruption of rifle aim by intense noise bursts. In Experiment 1 a trigger pull was followed occasionally by a noise burst. Aiming was disrupted for 1-2 s, an effect that habituated within days and recovered between days. Expected stimuli were less disruptive than were unexpected stimuli. Experiment 2 demonstrated that weak auditory prestimuli 100 ms before unexpected intense sounds also reduced noise-produced errors. Experiment 3 showed that the intratympanic reflex had not played a protective role in this effect. Experiment 4 showed that a weak tactile prestimulus increased both a muscular measure of the acoustic startle reaction and the perturbing effect of the noise burst on motor performance. In general, conditions that affect the amplitude of the acoustic startle reflex similarly influence the disruptive effect of a noise burst on motor performance, but the two measures are not correlated in the detail necessary to suggest a causative relationship.
Adult↗
Effect of increased noise levels by supersonic aircraft on annoyance levels and time estimations.
Several tests designed to assess the effects of increased noise levels created by the Concorde supersonic aircraft were administered to 48 residents living around Dulles International Airport and 31 persons not living near an airport. Results of a pretest questionnaire and lack of significant changes in annoyance levels and time estimations indicate that, while airport-area residents may be more conscious of aircraft noise, changes in the perceived intensities of sounds may not occur.
Adolescent↗
The perceived severity of tinnitus. Some observations concerning a large population of tinnitus clinic patients.
Detailed information about tinnitus was obtained from over 1800 patients attending a tinnitus clinic. Patients rated their tinnitus severity on a scale from 1 to 10 and also provided information concerning the quality, duration, localization, and other attributes of their tinnitus. In addition to standard audiometric tests, patients received tests for tinnitus pitch, loudness, maskability, and residual inhibition, and provided a brief medical history. The severity ratings of over 90% were at or above the scale value of 5. There was no correlation between rated severity and the loudness of tinnitus (obtained by a loudness balance procedure using external sounds matching the tinnitus pitch), thus confirming earlier observations. The severity also was not related to the type, quality, or pitch of tinnitus sound heard. However, severity ratings were highly correlated with incidence of sleep disturbance. Additional observations concerning relationships between perceived severity and other patient characteristics are discussed.
Acoustic Impedance Tests↗
Intensity dependence of auditory evoked dipole source activity in polydrug ecstasy users: evidence from an 18 months longitudinal study.
Numerous animal studies have been able to demonstrate neurotoxic damage to central serotonergic systems after exposure to 3,4-methylenedioxymethamphetamine (MDMA, ecstasy). It has been suggested that a high loudness dependence of auditory evoked potentials (LDAEP) and, particularly, of the tangential N1/P2 source activity is associated with a low functioning of serotonergic activity. Therefore, the LDAEP may be used as a non-invasive indicator for a possible neurotoxic damage caused by the long-term use of ecstasy in recreational users. We recorded auditory evoked potentials (AEP) with a passive listening paradigm in 18 polydrug ecstasy users at baseline (t1) and after 18 months (t2). Several aspects of ecstasy use, such as frequency of use, cumulative lifetime dose or period of abstinence were associated with the LDAEP for several tangential dipoles at both measuring times. However, we failed to demonstrate any significant relationship between drug use reported at follow-up and AEP changes from baseline to follow-up. Despite some incertitude these data suggest, yet do not unambiguously con.rm, the hypothesis that abstinent ecstasy users present with diminished central serotonergic activity. This feature of information processing is potentially related to the neurotoxic potential of ecstasy. However, alternative interpretations of these data refer to possible preexisting traits and the potential impact of other illicit drugs, particularly amphetamine, since ecstasy users typically exhibit polydrug use patterns. Thus, further research with larger sample sizes and prospective study designs are needed to definitively establish a causative link between ecstasy use and neurotoxicity-related dysfunctions in sensory processing.
Acoustic Stimulation↗
The Desired Sensation Level multistage input/output algorithm.
The Desired Sensation Level (DSL) Method was revised to support hearing instrument fitting for infants, young children, and adults who use modern hearing instrument technologies, including multichannel compression, expansion, and multimemory capability. The aims of this revision are to maintain aspects of the previous versions of the DSL Method that have been supported by research, while extending the method to account for adult-child differences in preference and listening requirements. The goals of this version (5.0) include avoiding loudness discomfort, selecting a frequency response that meets audibility requirements, choosing compression characteristics that appropriately match technology to the user's needs, and accommodating the overall prescription to meet individual needs for use in various listening environments. This review summarizes the status of research on the use of the DSL Method with pediatric and adult populations and presents a series of revisions that have been made during the generation of DSL v5.0. This article concludes with case examples that illustrate key differences between the DSL v4.1 and DSL v5.0 prescriptions.
Adolescent↗
The effects of digital noise reduction on the acceptance of background noise.
Modern hearing aids commonly employ digital noise reduction (DNR) algorithms. The potential benefit of these algorithms is to provide improved speech understanding in noise or, at the least, to provide relaxed listening or increased ease of listening. In this study, 22 adults were fitted with 16-channel wide-dynamic-range compression hearing aids containing DNR processing. The DNR includes both modulation-based and Wiener-filter-type algorithms working simultaneously. Both speech intelligibility and acceptable noise level (ANL) were assessed using the Hearing in Noise Test (HINT) with DNR on and DNR off. The ANL was also assessed without hearing aids. The results showed a significant mean improvement for the ANL (4.2 dB) for the DNR-on condition when compared to DNR-off condition. Moreover, there was a significant correlation between the magnitude of ANL improvement (relative to DNR on) and the DNR-off ANL. There was no significant mean improvement for the HINT for the DNR on condition, and on an individual basis, the HINT score did not significantly correlate with either aided ANL (DNR on or DNR off). These findings suggest that at least within the constraints of the DNR algorithms and test conditions employed in this study, DNR can significantly improve the clinically measured ANL, which may result in improved ease of listening for speech-in-noise situations.
Adult↗
A psychophysical method for assessing visual and acoustic hyperaesthesia in patients with mild head injury.
Although it is well known that patients with mild head injury (MHI) are less able to endure intense light and sound stimuli than normal people, there are few psychophysical studies that have objectively measured this type of hyperaesthesia. In the present study, using a computerised rating scale technique, both the maximal and submaximal levels of reduced tolerance to light and sound were assessed for a wide range of stimuli. Three to six days after the trauma, 40 MHI patients were significantly less tolerant to stimuli of intensities over 71 dB and 500 lux levels than controls. These intensities are common, and MHI patients may suffer as a consequence.
Adult↗
Frequency shift of individual spontaneous otoacoustic emissions in preterm infants.
In adults, spontaneous otoacoustic emissions (SOAE) have shown a considerable frequency stability. In preterm infants, however, the SOAE proved to show an apparent and consistent upward shift of frequency at increasing postconceptional age (PCA). In 25 ears of 14 preterm infants (PCA, 29.1-41.3 wk) a total of 66 SOAE frequencies were monitored, ranging from 1611 to 5774 Hz. All but one of the SOAE frequencies shifted toward higher frequency. The SOAE frequency shift rate in Hertz per week was proportionally constant relative to the SOAE frequency. The mean shift rate was 0.74 +/- 0.39%/wk. At increasing PCA, the SOAE frequency shift rate tended to slow down. A linear fit through the data predicted the SOAE frequency to stop at about 45-50-wk PCA. The frequency dependence and time course of the SOAE frequency shift strongly suggest cochlear maturation during the last period of gestation.
Acoustic Stimulation↗
The UCSF/Storz multichannel cochlear implant: patient results.
Using the four channel cochlear implant system with a vocoder-based processor developed at UCSF over an extensive period of research, clinical trials of the UCSF/Storz device were initiated in February 1985, under the sponsorship of Storz Instrument Company. To date, 13 patients have been implanted with this device, nine of whom have been fitted with their external processor and transmitter and have received at least their initial postoperative evaluation. Patient results have been extremely promising, with eight of the nine patients obtaining some open-set auditory only speech understanding. Most patients have demonstrated improvement over time and all patients have attained an enhancement in lipreading ability with the use of the UCSF/Storz device.
Adult↗