Measurement of Individual Loudness Functions by Trisection of Loudness Ranges

from Ear and Hearing

Abstract:
Objectives: Loudness-balance measurements with monaurally impaired subjects have shown that the shape of the loudness versus sound-pressure curve among hearing-impaired persons varies significantly. But the effectiveness of adjusting the compression characteristics of wide-dynamic-range compression hearing aids-the compression ratios, the variation of compression ratio with level, and the threshold of compression-to restore normal loudness growth for the individual patient has never been properly tested; individual loudness measurements have been too uncertain to permit meaningful individual adjustments. Recent investigators have reported standard deviations of such measurements in normal-hearing subjects of 6.4 dB and 7.8 dB. This investigation describes a method of measuring loudness function with a standard deviation in normal-hearing subjects of the order of 1 dB, both significantly lower than that of previous methods and sufficiently accurate for individual-subject adjustments.

Design: Each of nine normal-hearing subjects-seven of them inexperienced and one a 9-year-old was asked to make three successive loudness trisections within an amplitude range of 40 to 80 dB SPL, providing six points from which to plot a loudness-function curve between these limits. The individual and average curves were validated as accurate loudness functions by comparing them to the curve defined by the equation of loudness versus amplitude in current Standards. In a second validation experiment, the loudness functions of masked ears measured by trisection were compared to the loudness function of those ears measured by loudness balance between masked and unmasked ears.

Results: The difference between a loudness function based on the average of subject trisections and the loudness function defined by the ANSI Standard loudness equation was -1.92 dB at the lowest trisection level and +0.05 dB at the highest level. The standard deviations of subject responses were 1.63 dB for the lowest trisection level and 0.68 dB for the highest level, with an average of 1.1 dB. The across-subject standard deviation of the test-retest differences for three subjects was less than 1.7 dB for the first three lower level responses and less than 0.8 dB for the remaining three responses.

Conclusions: A trisection procedure for measuring loudness function showed validity and significantly less variation than previous loudness-measurement procedures. Such a procedure, once it has been validated for hearing-impaired subjects, makes it possible to test hearing aid design and fitting strategies that are based on individual-patient loudness functions.

Natural Boundaries in Gap Detection are Related to Categorical Perception of Stop Consonants

from Ear and Hearing

Abstract:
Objectives: The hypothesis that a natural auditory psychophysical discontinuity contributes to a perceptual category boundary between voiced and voiceless English stop consonants was examined.

Design: The relationships between voice onset time (VOT) phonetic boundary and gap-detection thresholds for conditions in which the sounds delimiting the gap were acoustically identical or different were examined in 18 native young adult English speakers. It was specifically hypothesized that between-channel gap-detection thresholds, in contrast to within-channel gap thresholds, would be better predictors of categorical VOT values for listeners. The stimuli used in the between-channel gap-detection task were designed such that dissimilar leading and trailing markers of the gap approximated a stop burst and a following vowel, both in terms of temporal and spectral relationships, while being devoid of phonetic identity. The stimuli used to examine the VOT measure were synthesized bilabial stop syllables in a continuum ranging from /ba/ to /pa/.

Results: Statistically significant larger gap thresholds were found for the between-channel conditions than for the within-channel condition (p < 0.05). The center frequency of the trailing marker affected the between-channel gap thresholds with the thresholds improving as the center frequency increased (p < 0.05). Statistically significant positive correlations and predictive linear relations were found between VOT phonetic boundaries and between-channel gap thresholds (p 0.05).

Conclusions: A relationship between the phonetic boundary of voiced-voiceless speech sounds and the auditory temporal resolution task of detecting gaps placed within dissimilar markers, regardless of the center frequency of the trailing marker noise burst, was demonstrated. Detection of gaps between different nonspeech acoustic markers and categorical perception of VOT seems to share the same underlying perceptual timing mechanisms in native English speakers.

Personality and Perception of Tinnitus

from Ear and Hearing

Abstract:
Objectives: Tinnitus has high prevalence and a wide range of etiologies and of impacts on sufferers. Our objective was to develop understanding of the role of personality in the perception of tinnitus in the general population. As a theoretical basis for this, we combined elements of a general model of signal detection with the ideas of ignition (development) and promotion (neural transmission) of tinnitus, and considered plausible roles for personality factors within this conceptual framework.

Design: We interviewed a birth cohort of 970 people aged 32 yr sampled from the general population. On the basis of questioning, we divided them into three groups, those without tinnitus, those with occasional tinnitus (including those with transient tinnitus of very brief duration), and those who experienced tinnitus most of the time. We also established how annoying or distressing the tinnitus was, and assessed personality using the Multidimensional Personality Questionnaire.

Results: Tinnitus was experienced rarely by 38.2% and half the time or more by 6.8% of those studied. Men and women did not differ in the amount of tinnitus reported, but women were more likely to find it annoying. People from lower socioeconomic backgrounds were more likely to report tinnitus. People with tinnitus were more socially withdrawn, reactive to stress, alienated, and less Self-Controlled. People who were more annoyed by tinnitus were more socially withdrawn, and men were more stress reactive and alienated.

Conclusions: Our interpretation of the findings is that personality influences the persistence of tinnitus by influencing the tendency to be aware of it. Consideration of personality factors may improve the ability to tailor tinnitus therapies, and the concept of awareness may benefit treatment outcomes by showing tinnitus sufferers a means of internalizing the locus of control over their symptoms.

The Development of Frequency Weighting for Speech in Children with a History of Otis Media with Effusion

from Ear and Hearing

Abstract:
Objectives: To determine the effect of chronic (recurrent) otitis media with effusion (OME) on frequency weighting in the perception of speech in noise. It was hypothesized that children with a history of OME weight speech information in the mid frequency region higher than control children.

Design: This is a matched cohort study looking at differences in frequency weighting in 12 children with a history of OME 1 to 2 wks after placement of tympanostomy tubes compared with 21 control children. Children were tested on their ability to identify key words in sentences presented in speech-shaped noise. The frequency content of the sentences was manipulated to determine the relative importance of frequencies in the regions of 1, 2, and 4 kHz. The frequency bands selected were 798 to 1212 Hz (low band), 1575 to 2425 Hz (mid band), and 3000 to 5000 Hz (high band). Initial testing involved adaptive runs where a speech-shaped masker was held at a constant level and the level of the speech with all three bands present varied. Once a level corresponding to 85% to 90% correct was identified, novel sentences were then presented at this signal-to-noise ratio in fixed block runs, with all bands present, or with one of the three bands omitted.

Results: The children in the OME group achieved 85% to 90% correct at a lower signal-to-noise ratio than controls in the adaptive testing, where all three speech bands were present. Fixed block testing indicated that children with OME history gave more weight to speech frequencies in the region of 2000 Hz compared with the age-matched control group.

Conclusions: The results are consistent with an interpretation that the development of frequency weighting in the perception of speech can be affected by a history of OME.

The Electrically Evoked Auditory Change Complex: Preliminary Results from Nucleus Cochlear Implant Users

from Ear and Hearing

Abstract:
Objectives: The purpose of this study was to determine if changes in the position of the stimulating electrode in the cochlea could be used to elicit the electrically evoked auditory change complex (EACC) from Nucleus cochlear implant users.

Design: Nine postlingually deafened adults participated in this study. Each study participant had been using his or her Nucleus CI24 cochlear implant for at least 3 mos before testing. The speech processor was bypassed and the output of the implanted receiver/stimulator was controlled directly. The stimulus was a 600 msec burst of a biphasic pulse train (1000 pps). In control conditions, the stimulating electrode was held constant and stimulation continued throughout the 600 msec recording interval. In experimental conditions, the EACC was elicited by introducing a change in the stimulating electrode 300 msec after the onset of the pulse train. The EACC was recorded using surface electrodes. Three recordings of 100 sweeps each were obtained for each stimulus condition. Bandpass filtering (1-100 Hz) was used to minimize contamination of the recordings by stimulus artifact. Averaged responses were then smoothed using a 40-msec wide boxcar filter and standard peak picking procedures were used to analyze these responses in the time domain.

Results: In each case, a clear onset response (P1-N1-P2) was recorded. In the experimental conditions, a second evoked potential, the EACC, was also recorded after the change in stimulating electrode. This second response had general morphological characteristics that were very similar to those of the onset response. Increasing the separation between the two stimulating electrodes in the experimental conditions resulted in a general trend toward increased EACC amplitudes.

Conclusions: This report describes results of a set of experiments in which the speech processor of the cochlear implant was bypassed and the EACC was recorded in response to a change in stimulating electrode position. EACC amplitude was shown to increase as the separation between the two stimulating electrodes increased. Although preliminary in nature, these results demonstrate the feasibility of recording the EACC in response to changes in stimulating electrode position from individual cochlear implant users.

Transmission Pathways of Vibratory Stimulation as Measured by Subjective Thresholds and Distortion-Product Otoacoustic Emissions

from Ear and Hearing

Abstract:
To clarify the contribution of the skull contents to the transmission of bone vibratory stimuli, and to examine the characteristics of such stimuli, we compared auditory thresholds and distortion-product otoacoustic emission (DPOAE) levels with a bone vibrator placed on various sites of the head, including the eye. The best audiometric thresholds and the highest DPOAE levels were obtained with the vibrator placed on the mastoid of the measuring side, or on the “ultrasound-window” of the temple. The audiometric thresholds obtained with the bone vibrator on the eye were similar to those of the forehead, and about 10 dB higher than at the best sites. DPOAEs were clearly present when elicited by a combination of air-conducted stimuli presented through an insert earphone and with the bone vibrator placed on the eye. These results indicate that vibratory sounds can be transmitted through the skull contents to the inner ear. The intracranial transmission pathway of the vibratory stimuli may play a significant role, particularly at low frequencies, and possibly also when the vibratory stimuli are applied on the skull bone.

Tune In or Tune Out: Age-Related Differences in Listening to Speech in Music

from Ear and Hearing

Abstract:
Objectives: To examine age-related differences in listening to speech in music.

Design: In the first experiment, the effect of music familiarity on word identification was compared with a standard measure of word identification in multitalker babble. The average level of the backgrounds was matched and two speech-to-background ratios were tested. In the second experiment, recognition recall was measured for background music heard during a word identification task.

Results: For older adults, word identification did not depend on the type of background, but for younger adults word identification was better when the background was familiar music than when it was unfamiliar music or babble. Younger listeners remembered background music better than older listeners, with the pattern of false alarms suggesting that younger listeners consciously processed the background music more than older listeners. In other words, younger listeners attempted to “tune in” the music background, but older listeners attempted to “tune out” the background.

Conclusions: These findings reveal age-related differences in listening to speech in music. When older listeners are confronted with a music background they tend to focus attention on the speech foreground. In contrast, younger listeners attend to both the speech foreground and music background. When music is familiar, this strategy adopted by younger listeners seems to be beneficial to word identification.

Young Adults’ Use and Output Level Settings of Personal Music Systems

from Ear and Hearing

Abstract:
Objectives: There are growing concerns over noise exposure via personal music system use by young adults. One purpose of this study was to evaluate the prevalence of personal music system use and the listening patterns associated with these systems in a large sample of young adults. A second purpose of this study was to measure the dB SPL in the ear canal of young adults while they blindly set the volume of a personal music system to four settings.

Design: In the first study, the personal music system use survey was completed by 1016 students at various locations on the San Diego State University campus. Questions included sex, age, ethnicity, race, and whether or not they used a personal music system. Students who answered Yes to using a personal music system were instructed to complete the remaining 11 closed-set questions. These questions dealt with type of earphones used with the system, most common listening environment, length of time per day the system was used, and the volume setting. The differences between women and men and across ethnicity and race were evaluated for the questions. In the second study, a probe microphone placed in the ear canal of 32 participants was used to determine the dB SPL of four loudness categories at which the participants blindly set the level of a personal music system: low, medium or comfortable, loud, and very loud.

Results: In study 1, over 90% of the participants who completed the survey reported using a personal music system. Over 50% of those who use a personal music system reported listening between 1 and 3 hrs and almost 90% reported listening at either a medium or loud volume. Men were significantly more likely to report listening to their system for a longer duration compared with women and more likely to report listening at a very loud volume. There was a trend for Hispanic or Latino students to report listening for longer durations compared with Not Hispanic or Latino students, but this difference was not statistically significant. Black or African American students were significantly more likely to report listening to their personal music system between 3 and 5 hrs and more than 5 hrs and to report listening at a very loud volume compared with other racial groups. In study 2, the mean dB SPL values for low, medium or comfortable, loud, and very loud were 62.0, 71.6, 87.7, and 97.8 dB SPL, respectively. Men set the level of very loud significantly higher than women.

Conclusions: It is clear that a vast majority of young adults who completed the personal music system use survey listen to a system using earphones. Most of the respondents listen between 1 and 3 hrs a day at a medium or loud volume. Based on the probe microphone measurement results, the volume settings for reported durations may not be hazardous for hearing. Long-term use of personal music systems, however, in combination with other noise exposures (i.e., recreational, occupational), and their effect on hearing remains a question for additional research.

Early intervention helps infants born deaf

fromYahoo! Health

NEW YORK (Reuters Health) – Infants with permanent hearing loss benefit in terms of language development from being enrolled very early — before 3 months of age — in intervention programs, according to a new study.

Linguistic aspects of Australian Aboriginal English

from Clinical Linguistics and Phonetics

Abstract
It is probable that the majority of the 455 000 strong Aboriginal population of Australia speak some form of Australian Aboriginal English (AAE) at least some of the time and that it is the first (and only) language of many Aboriginal children. This means their language is somewhere on a continuum ranging from something very close to Standard Australian English (SAE) at one end, through to something very close to creole at the other. The phonetics and phonology, grammar, and lexicon of AAE are influenced to varying degrees by the Australian Aboriginal language substrate. There are also some features typical of non-standard Englishes in general, and some which have been retained from earlier forms of the colonial language. Many teachers still see this variety as an uneducated or corrupted form of Standard Australian English, rather than as a different dialect of English that is just as efficient a medium of communication.

Vocal Changes in Patients Using Nasal Continuous Positive Airway Pressure

from the Journal of Voice

The aim of this prospective study is to assess the vocal changes in patients using nasal continuous positive airway pressure (CPAP). A total of 18 subjects using nasal CPAP were assessed by grading their voice perceptually as G0 for normal voice and G3 for severe hoarseness. Acoustic analysis was also performed and the following parameters were measured: fundamental frequency, habitual pitch, shimmer, relative average perturbation, voice turbulence index, and noise-to-harmonic ratio. The same was done for a control group matched according to age and gender. There was a statistically significant difference in the perceptual evaluation between the CPAP group and controls, with more patients in the former group having moderate hoarseness. There was also an increase in the perturbation parameters and a decrease in the fundamental frequency and habitual pitch in the CPAP group compared to controls. The increase in shimmer was statistically significant. The usage of nasal CPAP seems to induce vocal changes that are perceived as mild to moderate hoarseness, together with an increase in the perturbation parameters. These seem to be secondary to the upper airway dryness reported in these patients. The hypothetical effect of nasal CPAP on the sol layer of the vocal folds is discussed.

Surgical and medical complications in different cochlear implant devices

from Acta Oto-Laryngologica

Conclusion: There were no surgery-related complications among the patients in the current study. Positioner and removable magnets have been associated with postoperative problems, and the silicone devices were the only ones found by us to cause foreign body and allergic reactions. Objectives: To evaluate the complication rate in patients who were implanted with cochlear devices manufactured by different companies. Patients and methods: This retrospective study included all the patients who underwent cochlear implantation (138 Nucleus, 105 Med-El and 14 Clarion devices) via the suprameatal approach in our department during 2001-2007 and followed up for at least 18 months. Complications such as magnet displacement, foreign body reaction and protrusion of the positioner were considered as being implant-related. Allergy to implant, cholesteatoma, perforated tympanic membrane, intraoperative cerebrospinal fluid (CSF) leakage, wound breakdown, haematoma or seroma, and vestibular disturbances were considered to be patient-related. Results: Vestibular and wound problems emerged as the most common complications, but there were no significant differences in their rate of occurrence among the various devices. Explantation of the device was required in one case of foreign body reaction, one case of allergy to implant and one case of extrusion of the positioner followed by device failure.

A dual-route perspective on poor reading in a regular orthography: Evidence from phonological and orthographic lexical decisions

from Cognitive Neuropsychology

Impairments of the lexical and the nonlexical reading route were examined for German-speaking dyslexic readers by measuring accuracy and speed of phonological and orthographic lexical decisions. Different from English-based findings, we found little difficulty with the phonological distinction between pseudohomophones and nonwords, but a major difficulty with the orthographic distinction between words and pseudohomophones. Subtyping identified pure surface dyslexia cases but no case of pure phonological dyslexia. Dyslexic speed impairments were traced to three loci in the dual-route model: an impoverished orthographic lexicon, and slow access from orthographic to phonological lexicon entries (lexical route) and from graphemes to phonemes (nonlexical route). A review of distal cognitive deficits suggested that the orthographic lexicon is affected by phonological deficits and that the slow functioning of the lexical and the nonlexical route reflects a general visual-verbal speed impairment and not a purely visual-attentional deficit.

Different letter-processing strategies in diagnostic subgroups of developmental dyslexia

from Cognitive Neuropsychology

Normally reading adults (N = 15) and primary school children (N = 24) and two diagnostic subgroups of children with developmental dyslexia (N = 21)—all native German speakers—performed a successive same-different task with pairs of letters and nonletters (pseudoletters or geometrical shapes). The first item of a pair was always presented on its own, and the second either on its own or surrounded by a congruent or incongruent nontarget shape. Adults showed congruence effects with nonletters but not with letters, and children with both types of stimuli. Frequent-word reading-impaired dyslexics (N = 11) in addition showed dramatically slower overall reaction times. Nonword reading-impaired dyslexics (N = 10) showed congruence effects with nonletters but negative congruence effects with letters. The results support the notion that normal readers have established a special visual processing strategy for letters. Processing speed rather than reading expertise seems crucial for this strategy to emerge. The contrasting effects between subgroups of dyslexics reveal specific underlying deficits.

“Fragment errors” in deep dysgraphia: Further support for a lexical hypothesis

from Cognitive Neuropsychology

In addition to various lexical errors, the writing of patients with deep dysgraphia may include a large number of segmental spelling errors, which increase towards the end of the word. Frequently, these errors involve deletion of two or more letters resulting in so-called “fragment errors”. Different positions have been brought forward regarding their origin, including rapid decay of activation in the graphemic buffer and an impairment of more central (i.e., lexical or semantic) processing. We present data from a patient (M.D.) with deep dysgraphia who showed an increase of segmental spelling errors towards the end of the word. Several tasks were carried out to explore M.D.’s underlying functional impairment. Errors affected word-final positions in tasks like backward spelling and fragment completion. In a delayed copying task, length of the delay had no influence. In addition, when asked to recall three serially presented letters, a task which had not been carried out before, M.D. exhibited a preference for the first and the third letter and poor performance for the second letter. M.D.’s performance on these tasks contradicts the rapid decay account and instead supports a lexical-semantic account of segmental errors in deep dysgraphia. In addition, the results fit well with an implemented computational model of deep dysgraphia and segmental spelling errors.