1/9. Cutaneous-evoked tinnitus. I. Phenomenology, psychophysics and functional imaging.DC00166e and acute unilateral deafferentation of the auditory periphery (auditory and vestibular afferents) can induce changes in the central nervous system that may result in unique forms of tinnitus. These tinnitus perceptions can be controlled (turned on and off) or modulated (changed in pitch or loudness) by performing certain overt behaviors in other sensory/motor systems. Clinical reports from our laboratory and several other independent sources indicate that static change in eye gaze, from a neutral head-referenced position, is one such behavior that can evoke, modulate and/or suppress these phantom auditory events. This report deals with a new clinical entity and a form of tinnitus that can be evoked directly by cutaneous stimulation of the upper hand and fingertip regions. In 2 adults, cutaneous-evoked tinnitus was reported following neurosurgery for space-occupying lesions at the base of the skull and posterior craniofossa, where hearing and vestibular functions were lost completely and acutely in one ear (unilateral deafferentation) and facial nerve paralysis (unilateral deefferentation) was present either immediately following neurosurgery or had occurred as a delayed-onset event. Herein, we focus on the phenomenology of this discovery, provide perceptual correlates using contemporary psychophysical methods and document in one individual cutaneous-evoked tinnitus-related neural activity using functional magnetic resonance imaging. In a companion paper, neuroanatomical and physiological interactions between auditory and somatosensory systems, possible mechanistic accounts and relevant functional neuroimaging studies are reviewed.- - - - - - - - - - ranking = 1keywords = loudness (Clic here for more details about this article) |
2/9. Evaluation and treatment of severe hyperacusis.A 52-year-old male was evaluated by the authors after initially reporting fullness in his left ear while traveling on an airplane. A unique feature of the patient's complaint was the development of severe bilateral hyperacusis (loudness discomfort levels of between 20-34 dB HL) in spite of the fact that the hearing loss was initially reported in the left ear. To achieve loudness comfort, the patient was initially fit with ER-25 musician earplugs that proved to be unsuccessful. The patient next purchased earplugs and earmuffs from a gun shop in order to obtain relief from the pain and discomfort caused by his exposure to everyday environmental sounds. This paper describes the use of hearing devices that proved to be effective in providing attenuation sufficient that the patient rarely needs to rely on earplugs and earmuffs for relief from his hyperacusis.- - - - - - - - - - ranking = 2keywords = loudness (Clic here for more details about this article) |
3/9. Adaptation to loudness and environmental stimuli in three newly fitted hearing aid users.Hearing aid fitting strategies can be categorized according to whether a loudness normalization or a loudness equalization rationale is employed. Regardless of the underlying rationale, the amount of patient participation in determining the initial hearing aid settings will vary when an audiologist-driven (AD) versus a patient-driven protocol is employed. When an AD protocol is used, few changes are made during the initial fitting session based on user feedback. It is assumed that the patient will adapt to the loudness and/or sound quality provided by the hearing aids if not immediately acceptable. The following three case reports document varying degrees of adaptation to hearing aid settings derived using an AD approach. Clinical implications will be discussed.- - - - - - - - - - ranking = 7keywords = loudness (Clic here for more details about this article) |
4/9. Fitting low ratio compression to people with severe and profound hearing losses.OBJECTIVE: In this study, we aimed to determine the extent to which wide dynamic range compression and compression limiting could benefit severely and profoundly hearing-impaired adults. DESIGN: Subjects were fitted with multi-memory hearing aids incorporating frequency independent input-controlled compression with a 2:1 compression ratio and output-controlled compression limiting. The input compression threshold (CT) was varied to establish the lowest level that maintained audibility for conversational intensity speech without acoustic feedback oscillation. Where a low (40 to 57 dB SPL) CT was possible, this was compared with a moderate (65 to 74 dB SPL) level. The preferred input compression setting was subsequently compared with linear, compression-limited amplification in the same aids. In the three cases where 2:1 input compression could not be used, because of feedback or loudness insufficiency problems, compression limiting was compared with peak clipping. Field trials were conducted over a 2- or 3-mo period to establish preferences. RESULTS: Nine of the 16 subjects preferred the inclusion of the higher level input compression, and one preferred lower level input compression. Four subjects preferred linear, compression-limited amplification, one favored peak clipping, and one could not be satisfied with any of the options provided. CONCLUSIONS: 2:1 input compression was useful, and preferred by 10 of the subjects, but for nine subjects the preferred CT was relatively high. With a group 4-frequency average loss of 87 dB HTL, the results demonstrate that fast-acting, low compression ratio systems can be useful for losses traditionally regarded as the domain of linear amplification.- - - - - - - - - - ranking = 1keywords = loudness (Clic here for more details about this article) |
5/9. MRI scanning and incus fixation in vibrant soundbridge implantation.OBJECTIVE: Presentation of patient data after Vibrant sound-bridge (VS) implantation/explantation with respect to magnetic resonance imaging (MRI) compatibility and stability of incus fixation of the implant. STUDY DESIGN: In a retrospective case review, we report on two patients who had to be diagnosed by cranial MRI scans after previous implantation of a VS. Moreover, in one of these cases, the incus was removed after explantation of the VS because of a peripheral hearing loss. This enabled a microscopic evaluation of the incus. At the long process of the incus, the floating mass transmitter (FMT) has been fixed for 4 years. SETTING: Tertiary referral center. SUBJECTS: Two patients who fulfilled, at the time of implantation, the criteria for implantation of a VS. RESULTS: In both cases, no demagnetization of the external magnet nor of the FMT were found. Device function after the MRI scans were normal. Pure-tone audiometric thresholds remained unchanged after the MRI scanning and the scanning-related magnetic forces. In both cases, the FMT fixation of the incus was found to be regular. In one case, the fixation was checked by an additional tympanoscopy 1 year after the implantation, and in the other case it was assessed by recording the functional gain of the VS (which was normal) after the MRI scanning. One patient complained about a transient hyperacuity due to the loudness during the MRI scanning procedure. MRI scans showed a blackening of the implant area with spherical distortions of the picture. CONCLUSION: Although MRI scanning (at 1.5 tesla [T]) with the FMT in place did not lead to adverse effects in the two patients, systematic in vitro studies are required to determine a possible magnetization threshold that could impair the VS function when MRI scans are applied in those patients. The microscopically observed erosions of the long process of the incus after 4 years of FMT clamp fixation show similarities to findings after stapes revision surgery. However, this limited experience in one case does not allow us to make conclusions on the long-term stability of the incus fixation.- - - - - - - - - - ranking = 1keywords = loudness (Clic here for more details about this article) |
6/9. Magnitude estimation of loudness. III: Performance of selected hearing aid users.Aided and unaided loudness functions for narrow-band noise stimuli were obtained from hearing-impaired listeners with a magnitude estimation procedure. A comparison of aided loudness functions with those obtained from normal-hearing subjects suggests that the hearing aids did not restore normal loudness relations among the spectral components of speech stimuli. Instead, aided loudness functions tend to reflect an interaction between the abnormal loudness growth that frequently characterizes sensorineural hearing loss and the saturation characteristics of the hearing aid.- - - - - - - - - - ranking = 9keywords = loudness (Clic here for more details about this article) |
7/9. Aging and auditory site of lesion.The purpose of this study was to examine and quantify the functional auditory problems of presbycusis through a battery of recently developed diagnostic tests and to evaluate the usefulness of these tests with an elderly population. Diagnostic measures used were impedence measures, speech discrimination tests, synthetic sentence identification, compressed speech, two measures of tone decay, the short increment sensitivity index, a digit span test, and auditory brain stem response audiometry. Significant differences were found between scores for elderly subjects and those of young subjects who had similar audiograms. Use of the Metz test as an objective measure of recruitment yielded results suggesting a higher incidence of recruitment than evidenced by previous studies using loudness balancing procedures. The Olsen-Noffsinger procedure of quantifying tone decay revealed a greater difference between age groups than did the Suprathreshold Adaptation Test. Synthetic sentence identification revealed the most consistent age effect among the tests of central auditory function. Auditory brain stem response audiometry revealed several examples of abnormally long interpeak latencies. It is concluded that there is both behavioral and electrophysiological evidence of central and peripheral auditory disorder frequently accompanying senescence.- - - - - - - - - - ranking = 1keywords = loudness (Clic here for more details about this article) |
8/9. Some observations in a case of acoustic neuroma.The subject was a 47-year-old male with a moderate asymmetrical sensorineural hearing loss that initially presented cochlear signs except for positive stapedius reflex results. Over the course of only five weeks, he developed the audiological constellation of retrocochlear involvement. The retrocochlear results were confirmed by the removal of an acoustic tumour. The results highlight the importance of audiological monitoring and reflex measures in the identification of acoustic neuromas. Several observations provide insight into the apparent relationship between loudness and the stapedius reflex. The findings are discussed with reference to a proposed extension of Borg's recent theory that elevated reflex thresholds and reflex decay reflect differing degrees of the eighth nerve destruction.- - - - - - - - - - ranking = 1keywords = loudness (Clic here for more details about this article) |
9/9. Just audible pitch and loudness modulations with cochlear impairment.Just noticeable combined modulations in amplitude and frequency were determined for an observer (DP) with a bowl-shaped sensorineural hearing loss of about 40 dB between 1 and 2 kHz. In all stimulus conditions, interactions were found between the detection of amplitude modulations and frequency modulations. These interactions appear to correlate quantitatively with the effect of frequency on loudness (as given by the slope of the equal-loudness contour). When this effect of frequency on loudness if taken into account, the data support the hypothesis of independent detection of pitch and loudness modulations. The experimental data are also discussed in relation to the single-mechanism hypothesis for the detection of changes in amplitude and frequency (Zwicker, Maiwald). This model could not provide a satisfactory explanation of interactions between amplitude and frequency.- - - - - - - - - - ranking = 8keywords = loudness (Clic here for more details about this article) |