Transcutaneous Electrical Stimulation of Subjective Tinnitus

from ORL -Journal for Oto-Rhino-Laryngology and Its Related Specialties

Aim: The effect of the transcutaneous application of the electrical stimulus on tinnitus perception has been reviewed in a placebo-controlled, randomized and comparative analysis to eventually determine the outcome of the therapeutic role of the therapy. Method: There are 42 patients who were randomized into 2 groups according to their order of admission. Group A consists of 31 patients who were subjected to transcutaneous electrical stimulation 3 times a week for 1 month. Group B includes 11 patients who had electrical stimulus attachment but where no stimulus was given (placebo group). The stimulator is a custom-made device which generates direct and alternative current in 10-200 Hz frequency. An alternative low-frequency (not >100 Hz) pulsed current was used for tinnitus therapy through a preauricular skin electrode. The amplitude of stimulus ranged between 50 and 2,000 mA. The pulse frequency was 30 Hz. Each session lasted for 25 min for both groups. Statistical analysis was performed. Result: The rate of improvement following the therapy was 42.8% (18/42) in the electrical therapy group and 28.5% (4/14) in the placebo group. Conclusion: Electrical suppression of the tinnitus does not offer a promising outcome for patients with tinnitus in the presented study.

American Academy Of Otolaryngology-Head And Neck Surgery Approves Policy Statement On Micropressure Therapy For Meniere’s Disease

from Medical News Today.com

Medtronic, Inc. (NYSE: MDT) announced that the American Academy of Otolaryngology – Head and Neck Surgery approved a policy statement concluding that the use of micropressure for Ménière’s disease including the Medtronic Meniett® device is appropriate when other medical treatments fail.

Hyperbaric Oxygen Treatment Restores Sudden Hearing Loss in a Patient with Fabry Disease

from ORL -Journal for Oto-Rhino-Laryngology and Its Related Specialties

Fabry disease is an X-linked inherited disorder of glycosphingolipid metabolism due to the deficient activity of a lysosomal enzyme, -galactosidase A. The resultant systemic accumulation of sphingolipids can lead to progressive and sudden hearing loss alongside renal, cardiac and cerebrovascular complications. Although replacement therapy seems to be beneficial for cochlear function, few data are available regarding treatment of sudden hearing loss. This case report describes the course of a unilateral sudden hearing loss in a young (15-year-old) male patient and its improvement following hyperbaric oxygen treatment.

A glimpsing account for the benefit of simulated combined acoustic and electric hearing

from the Journal of the Acoustical Society of America

The benefits of combined electric and acoustic stimulation (EAS) in terms of speech recognition in noise are well established; however the underlying factors responsible for this benefit are not clear. The present study tests the hypothesis that having access to acoustic information in the low frequencies makes it easier for listeners to glimpse the target. Normal-hearing listeners were presented with vocoded speech alone (V), low-pass (LP) filtered speech alone, combined vocoded and LP speech (LP+V) and with vocoded stimuli constructed so that the low-frequency envelopes were easier to glimpse. Target speech was mixed with two types of maskers (steady-state noise and competing talker) at −5 to 5 dB signal-to-noise ratios. Results indicated no advantage of LP+V in steady noise, but a significant advantage over V in the competing talker background, an outcome consistent with the notion that it is easier for listeners to glimpse the target in fluctuating maskers. A significant improvement in performance was noted with the modified glimpsed stimuli over the original vocoded stimuli. These findings taken together suggest that a significant factor contributing to the EAS advantage is the enhanced ability to glimpse the target. ©2008 Acoustical Society of America

Binaural speech unmasking and localization in noise with bilateral cochlear implants using envelope and fine-timing based strategies

from the Journal of the Acoustical Society of America

Four adult bilateral cochlear implant users, with good open-set sentence recognition, were tested with three different sound coding strategies for binaural speech unmasking and their ability to localize 100 and 500 Hz click trains in noise. Two of the strategies tested were envelope-based strategies that are clinically widely used. The third was a research strategy that additionally preserved fine-timing cues at low frequencies. Speech reception thresholds were determined in diotic noise for diotic and interaurally time-delayed speech using direct audio input to a bilateral research processor. Localization in noise was assessed in the free field. Overall results, for both speech and localization tests, were similar with all three strategies. None provided a binaural speech unmasking advantage due to the application of 700 µs interaural time delay to the speech signal, and localization results showed similar response patterns across strategies that were well accounted for by the use of broadband interaural level cues. The data from both experiments combined indicate that, in contrast to normal hearing, timing cues available from natural head-width delays do not offer binaural advantages with present methods of electrical stimulation, even when fine-timing cues are explicitly coded. ©2008 Acoustical Society of America

Spectral weighting strategies for hearing-impaired listeners measured using a correlational method

from the Journal of the Acoustical Society of America

Spectral weighting strategies using a correlational method [R. A. Lutfi, J. Acoust. Soc. Am. 97, 1333–1334 (1995); V. M. Richards and S. Zhu, J. Acoust. Soc. Am. 95, 423–424 (1994)] were measured in ten listeners with sensorineural-hearing loss on a sentence recognition task. Sentences and a spectrally matched noise were filtered into five separate adjacent spectral bands and presented to listeners at various signal-to-noise ratios (SNRs). Five point-biserial correlations were computed between the listeners’ response (correct or incorrect) on the task and the SNR in each band. The stronger the correlation between performance and SNR, the greater that given band was weighted by the listener. Listeners were tested with and without hearing aids on. All listeners were experienced hearing aid users. Results indicated that the highest spectral band (~2800–11 000 Hz) received the greatest weight in both listening conditions. However, the weight on the highest spectral band was less when listeners performed the task with their hearing aids on in comparison to when listening without hearing aids. No direct relationship was observed between the listeners’ weights and the sensation level within a given band. ©2008 Acoustical Society of America

Binaural speech unmasking and localization in noise with bilateral cochlear implants using envelope and fine-timing based strategies

from the Journal of the Acoustical Society of America

Four adult bilateral cochlear implant users, with good open-set sentence recognition, were tested with three different sound coding strategies for binaural speech unmasking and their ability to localize 100 and 500 Hz click trains in noise. Two of the strategies tested were envelope-based strategies that are clinically widely used. The third was a research strategy that additionally preserved fine-timing cues at low frequencies. Speech reception thresholds were determined in diotic noise for diotic and interaurally time-delayed speech using direct audio input to a bilateral research processor. Localization in noise was assessed in the free field. Overall results, for both speech and localization tests, were similar with all three strategies. None provided a binaural speech unmasking advantage due to the application of 700 µs interaural time delay to the speech signal, and localization results showed similar response patterns across strategies that were well accounted for by the use of broadband interaural level cues. The data from both experiments combined indicate that, in contrast to normal hearing, timing cues available from natural head-width delays do not offer binaural advantages with present methods of electrical stimulation, even when fine-timing cues are explicitly coded. ©2008 Acoustical Society of America

Effects of in-the-ear microphone directionality on sound direction identification

from the Journal of the Acoustical Society of America

As advanced signal processing algorithms have been proposed to enhance hearing protective device (HPD) performance, it is important to determine how directional microphones might affect the localization ability of users and whether they might cause safety hazards. The effect of in-the-ear microphone directivity was assessed by measuring sound source identification of speech in the horizontal plane. Recordings of speech in quiet and in noise were made with Knowles Electronic Manikin for Acoustic Research wearing bilateral in-the-ear hearing aids with microphones having adjustable directivity (omnidirectional, cardioid, hypercardioid, supercardioid). Signals were generated from 16 locations in a circular array. Sound direction identification performance of eight normal hearing listeners and eight hearing-impaired listeners revealed that directional microphones did not degrade localization performance and actually reduced the front–back and lateral localization errors made when listening through omnidirectional microphones. The summed rms speech level for the signals entering the two ears appear to serve as a cue for making front–back discriminations when using directional microphones in the experimental setting. The results of this study show that the use of matched directional microphones when worn bilaterally do not have a negative effect on the ability to localize speech in the horizontal plane and may thus be useful in HPD design. ©2008 Acoustical Society of America

Pulse-rate discrimination by cochlear-implant and normal-hearing listeners with and without binaural cues

from the Journal of the Acoustical Society of America

Experiment 1 measured rate discrimination of electric pulse trains by bilateral cochlear implant (CI) users, for standard rates of 100, 200, and 300 pps. In the diotic condition the pulses were presented simultaneously to the two ears. Consistent with previous results with unilateral stimulation, performance deteriorated at higher standard rates. In the signal interval of each trial in the dichotic condition, the standard rate was presented to the left ear and the (higher) signal rate was presented to the right ear; the non-signal intervals were the same as in the diotic condition. Performance in the dichotic condition was better for some listeners than in the diotic condition for standard rates of 100 and 200 pps, but not at 300 pps. It is concluded that the deterioration in rate discrimination observed for CI users at high rates cannot be alleviated by the introduction of a binaural cue, and is unlikely to be limited solely by central pitch processes. Experiment 2 performed an analogous experiment in which 300-pps acoustic pulse trains were bandpass filtered (3900–5400 Hz) and presented in a noise background to normal-hearing listeners. Unlike the results of experiment 1, performance was superior in the dichotic than in the diotic condition. ©2008 Acoustical Society of America

Speech segregation in rooms: Monaural, binaural, and interacting effects of reverberation on target and interferer

from the Journal of the Acoustical Society of America

Speech reception thresholds were measured in virtual rooms to investigate the influence of reverberation on speech intelligibility for spatially separated targets and interferers. The measurements were realized under headphones, using target sentences and noise or two-voice interferers. The room simulation allowed variation of the absorption coefficient of the room surfaces independently for target and interferer. The direct-to-reverberant ratio and interaural coherence of sources were also varied independently by considering binaural and diotic listening. The main effect of reverberation on the interferer was binaural and mediated by the coherence, in agreement with binaural unmasking theories. It appeared at lower reverberation levels than the effect of reverberation on the target, which was mainly monaural and associated with the direct-to-reverberant ratio, and could be explained by the loss of amplitude modulation in the reverberant speech signals. This effect was slightly smaller when listening binaurally. Reverberation might also be responsible for a disruption of the mechanism by which the auditory system exploits fundamental frequency differences to segregate competing voices, and a disruption of the “listening in the gaps” associated with speech interferers. These disruptions may explain an interaction observed between the effects of reverberation on the targets and two-voice interferers. ©2008 Acoustical Society of America

Using blind source separation techniques to improve speech recognition in bilateral cochlear implant patients

from the Journal of the Acoustical Society of America

Bilateral cochlear implants seek to restore the advantages of binaural hearing by improving access to binaural cues. Bilateral implant users are currently fitted with two processors, one in each ear, operating independent of one another. In this work, a different approach to bilateral processing is explored based on blind source separation (BSS) by utilizing two implants driven by a single processor. Sentences corrupted by interfering speech or speech-shaped noise are presented to bilateral cochlear implant users at 0 dB signal-to-noise ratio in order to evaluate the performance of the proposed BSS method. Subjects are tested in both anechoic and reverberant settings, wherein the target and masker signals are spatially separated. Results indicate substantial improvements in performance in both anechoic and reverberant settings over the subjects’ daily strategies for both masker conditions and at various locations of the masker. It is speculated that such improvements are due to the fact that the proposed BSS algorithm capitalizes on the variations of interaural level differences and interaural time delays present in the mixtures of the signals received by the two microphones, and exploits that information to spatially separate the target from the masker signals. ©2008 Acoustical Society of America

Incorporation of phonetic constraints in acoustic-to-articulatory inversion

from the Journal of the Acoustical Society of America

This study investigates the use of constraints upon articulatory parameters in the context of acoustic-to-articulatory inversion. These speaker independent constraints, referred to as phonetic constraints, were derived from standard phonetic knowledge for French vowels and express authorized domains for one or several articulatory parameters. They were experimented on in an existing inversion framework that utilizes Maeda’s articulatory model and a hypercubic articulatory-acoustic table. Phonetic constraints give rise to a phonetic score rendering the phonetic consistency of vocal tract shapes recovered by inversion. Inversion has been applied to vowels articulated by a speaker whose corresponding x-ray images are also available. Constraints were evaluated by measuring the distance between vocal tract shapes recovered through inversion to real vocal tract shapes obtained from x-ray images, by investigating the spreading of inverse solutions in terms of place of articulation and constriction degree, and finally by studying the articulatory variability. Results show that these constraints capture interdependencies and synergies between speech articulators and favor vocal tract shapes close to those realized by the human speaker. In addition, this study also provides how acoustic-to-articulatory inversion can be used to explore acoustical and compensatory articulatory properties of an articulatory model. ©2008 Acoustical Society of America

Seeing pitch: Visual information for lexical tones of Mandarin-Chinese

from the Journal of the Acoustical Society of America

Mandarin perceivers were tested in visual lexical-tone identification before and after learning. Baseline performance was only slightly above chance, although there appeared to be some visual information in the speakers’ neck and head movements. When participants were taught to use this visible information in two experiments, visual tone identification improved significantly. There appears to be a relationship between the production of lexical tones and the visible movements of the neck, head, and mouth, and this information can be effectively used after a short training session. ©2008 Acoustical Society of America

A longitudinal investigation of oral narrative skills in children with mixed reading disability

from the International Journal of Speech-Language Pathology

This 2-year longitudinal study investigated oral narrative ability in 14 children with mixed reading disability and their age-matched peers with typical development. The children were aged between 6;4 and 7;8 at the commencement of the study and assessments were administered individually to the children on three occasions over a 2-year period. Oral narratives were elicited in a personal narrative context (i.e., the child was encouraged to relate personal experiences in response to photo prompts) and a story retelling context. Oral narrative comprehension was assessed in a fictional story context through questions relating to story structure elements. Results indicated that the children with mixed reading disability demonstrated inferior oral narrative production and oral narrative comprehension performance compared to children with typical reading development at each assessment occasion. To further explore these children’s difficulties in oral narrative ability, their performance was compared to a reading comprehension-age match control group at the third assessment trial. The results suggested the children with mixed reading disability had a specific deficit in oral narrative comprehension.

A second chance: Recovering language with aphasia

from the International Journal of Speech-Language Pathology

Dr Christopher Green is a well-known paediatrician and parenting author, who appeared frequently on Australian radio and television and lectured in Australia and many countries around the world. In 1999, Dr Green had a stroke which left him with aphasia and ended his career. After the death of his wife in 2004, Dr Green used exercise and the goal of writing again to lift himself out of his grief. With the help of a gifted editor, he wrote a new edition of his best-selling book Toddler Taming (Green, 2006), and in the process recovered much of his language. Dr Green is the Patron of the Australian Aphasia Association, and has in recent years returned to public speaking. In this address, he shares his message that the language gains made with aphasia may occur over decades, not merely one or two years. This article is an edited version of the keynote speech Dr Green presented at the Speech Pathology Australia annual conference in 2007.