Measuring hearing in the harbor seal (Phoca vitulina): comparison of behavioral and auditory brainstem response techniques

Auditory brainstem response (ABR) and standard behavioral methods were compared by measuring in-air audiograms for an adult female harbor seal (Phoca vitulina). Behavioral audiograms were obtained using two techniques: the method of constant stimuli and the staircase method. Sensitivity was tested from 0.250 to 30 kHz. The seal showed good sensitivity from 6 to 12 kHz [best sensitivity 8.1 dB (re 20 microPa2 x s) RMS at 8 kHz]. The staircase method yielded thresholds that were lower by 10 dB on average than the method of constant stimuli. ABRs were recorded at 2, 4, 8, 16, and 22 kHz and showed a similar best range (8-16 kHz). ABR thresholds averaged 5.7 dB higher than behavioral thresholds at 2, 4, and 8 kHz. ABRs were at least 7 dB lower at 16 kHz, and approximately 3 dB higher at 22 kHz. The better sensitivity of ABRs at higher frequencies could have reflected differences in the seal's behavior during ABR testing and/or bandwidth characteristics of test stimuli. These results agree with comparisons of ABR and behavioral methods performed in other recent studies and indicate that ABR methods represent a good alternative for estimating hearing range and sensitivity in pinnipeds, particularly when time is a critical factor and animals are untrained.     

Alarm signals of the great gerbil: acoustic variation by predator context, sex, age, individual, and family group

The great gerbil, Rhombomys opinus, is a highly social rodent that usually lives in family groups consisting of related females, their offspring, and an adult male. The gerbils emit alarm vocalizations in the presence of diverse predators with different hunting tactics. Alarm calls were recorded in response to three predators, a monitor lizard, hunting dog, and human, to determine whether the most common call type, the rhythmic call, is functionally referential with regard to type of predator. Results show variation in the alarm calls of both adults and subadults with the type of predator. Discriminant function analysis classified an average of 70% of calls to predator type. Call variation, however, was not limited to the predator context, because signal structure also differed by sex, age, individual callers, and family groups. These variations illustrate the flexibility of the rhythmic alarm call of the great gerbil and how it might have multiple functions and communicate in multiple contexts. Three alarm calls, variation in the rhythmic call, and vibrational signals generated from foot-drumming provide the gerbils with a varied and multi-channel acoustic repertoire.     

Underlying dimensions and individual differences in auditory, visual, and auditory-visual vowel perception by hearing-impaired children

Vowel perception studies were conducted on a group of four adolescent children with congenital profound sensorineural hearing impairments in the three conditions of audition alone, vision alone, and audition plus vision. Data were analyzed using the ALSCAL multidimensional scaling procedure to identify the underlying dimensions and individual differences in dimension emphasis. The three dimensions obtained from the analysis of data for the audition alone condition were interpreted as the parameters of first and second formant frequencies, and vowel length. The one dimension for the vision alone condition was interpreted as the parameter of the width of the internal lip opening. The three dimensions for the audition plus vision condition were interpreted as the parameters of first formant frequency, vowel length, and the width of the internal lip opening. Subject variations in parameter preferences were observed for the audition alone and audition plus vision conditions but not for the vision alone condition.     

The interaction of glottal-pulse rate and vocal-tract length in judgements of speaker size, sex, and age

Glottal-pulse rate (GPR) and vocal-tract length (VTL) are related to the size, sex, and age of the speaker but it is not clear how the two factors combine to influence our perception of speaker size, sex, and age. This paper describes experiments designed to measure the effect of the interaction of GPR and VTL upon judgements of speaker size, sex, and age. Vowels were scaled to represent people with a wide range of GPRs and VTLs, including many well beyond the normal range of the population, and listeners were asked to judge the size and sex/age of the speaker. The judgements of speaker size show that VTL has a strong influence upon perceived speaker size. The results for the sex and age categorization (man, woman, boy, or girl) show that, for vowels with GPR and VTL values in the normal range, judgements of speaker sex and age are influenced about equally by GPR and VTL. For vowels with abnormal combinations of low GPRs and short VTLs, the VTL information appears to decide the sex/age judgement.     

Vocal tract resonances in singing: Strategies used by sopranos, altos, tenors, and baritones

The first two vocal tract resonances (R1 and R2) of 22 classically trained sopranos, altos, tenors, and baritones were measured while they sang four different vowels over their normal pitch range. The resonances of the tract and the harmonics of the voice were measured simultaneously by injecting a broadband acoustic current into the tract at their mouth. Sopranos were found to tune R1 close to the fundamental frequency f(0) (R1:f(0) tuning) over at least part of their upper range for all vowels studied, particularly when f(0) was around or above the value of R1 for speech. Additionally, most sopranos employed R2:2f(0) tuning over some of their range, often simultaneously with R1:f(0) tuning. Altos used R1:f(0) tuning for vowels having lower values of R1 in speech, but can switch to R1:2f(0) tuning in the lower part of their range. Tenors and baritones generally used R1:2f(0) and R1:3f(0) tunings over part of their range and employed a number of different tunings to higher harmonics at lower pitch. These results indicate that singers can repeatedly tune their resonances with precision, and that there can be considerable differences in the resonance strategies used by individual singers, particularly for voices in the lower ranges.     

Perception of temporal differences in speech by "normal-hearing" adults: effects of age and intensity

Many older people have greater difficulty processing speech at suprathreshold levels than can be explained by standard audiometric configurations. Some of the difficulty may involve the processing of temporal information. Temporal information can signal linguistic distinctions. The voicing distinction, for example, that separates pairs of words such as "rapid" and "rabid" can be signaled by temporal information: longer first vowel and shorter closure characterize "rabid"; shorter vowel and longer closure characterize "rapid." In this study, naturally produced tokens of "rabid" were low-pass filtered at 3500 Hz and edited to create vowel and (silent) closure duration continua. Pure-tone audiograms and speech recognition scores were used to select the ten best-hearing subjects among 50 volunteers over age 55. Randomizations of the stimuli were presented for labeling at intensity levels of 60 and 80 dB HL to this group and to ten normal-hearing volunteers under age 25. Results showed highly significant interactions of age with the temporal factors and with intensity: the older subjects required longer silence durations before reporting "rapid," especially for the shorter vowel durations and for the higher intensity level. These data suggest that age may affect the relative salience of different acoustic cues in speech perception, and that age-related hearing loss may involve deficits in the processing of temporal information, deficits that are not measured by standard audiometry.     

Personality,Psychological Factors,and Behavioral Tendencies in Children With Vocal Nodules: A Systematic Review

ObjectivesThis systematic review examined the evidence linking vocal nodule development in children to personality traits, psychological factors, and associated behavioral tendencies.MethodsFour electronic databases—PubMed, Scopus, ScienceDirect, EBSCO Host—as well as the reference lists from articles (including online sources) were searched. After screening for relevance, eight comparative, case-control studies were identified that met inclusion criteria. The quality of each study was evaluated by two raters using a modified, standardized checklist.ResultsFour studies were rated as “good quality” and four were “fair”. The questionnaires used to measure personality or psychological factors varied widely among the studies, and the results linking personality dispositions (and associated behavioral inclinations) to vocal nodule development in children were mixed.ConclusionsFair to good quality evidence exists to suggest that psychological factors or personality traits related to extraversion and impulsivity (and their related behavioral inclinations) might predispose children to vocal nodules and deserve further attention. Clinical implications, limitations of the current systematic review, and recommendations for future research are also discussed.     

Sources of overdispersion in a K-rich feldspar sample from north-central India: Insights from De,K content and IRSL age distributions for individual grains

Luminescence dating of individual sand-sized grains of quartz is a well-established technique in Quaternary geochronology, but the most ubiquitous mineral on the surface of the Earth—feldspar—has received much less attention at the single-grain level. In this study, we estimated single-grain equivalent dose values and infrared stimulated luminescence (IRSL) ages for K-rich feldspar (KF) grains from a fluvial sample underlying Youngest Toba Tuff (YTT) deposits in north-central India, and compared these ages (corrected for anomalous fading) with those obtained from individual grains of quartz from the same sample. Both minerals have broadly similar single-grain age distributions, but both are greatly overdispersed and most grains have ages substantially younger than the expected age of the YTT deposit (～74 ka). Almost half (45%) of KF grains used for age calculation have fading rates statistically consistent with zero, but the age distribution of these grains is as dispersed as that of the entire population. We obtained a similar distribution of ages calculated for 51 grains using their individually measured internal K contents, which exhibited only minor grain-to-grain variation. Given the lack of dependency of single-grain ages on the measured fading rates and internal K contents, and the overall adequacy of bleaching of grains collected from a sandbar in the modern river channel, we consider the spread in ages is most likely due to mixing, at the time of deposition and after the YTT event, of potentially well-bleached fluvially-transported sediments with older grains derived from slumping of riverbank deposits. Some spread may also be due to natural variations in the IRSL properties of individual KF grains.     

Language specificity in the perception of voiceless sibilant fricatives in Japanese and English: implications for cross-language differences in speech-sound development

Both English and Japanese have two voiceless sibilant fricatives, an anterior fricative /s/ contrasting with a more posterior fricative /∫/. When children acquire sibilant fricatives, English children typically substitute [s] for /∫/, whereas Japanese children typically substitute [∫] for /s/. This study examined English- and Japanese-speaking adults' perception of children's productions of voiceless sibilant fricatives to investigate whether the apparent asymmetry in the acquisition of voiceless sibilant fricatives reported previously in the two languages was due in part to how adults perceive children's speech. The results of this study show that adult speakers of English and Japanese weighed acoustic parameters differently when identifying fricatives produced by children and that these differences explain, in part, the apparent cross-language asymmetry in fricative acquisition. This study shows that generalizations about universal and language-specific patterns in speech-sound development cannot be determined without considering all sources of variation including speech perception.     

Identification of vowels in quiet, noise, and reverberation: relationships with age and hearing loss

Vowel identification in quiet, noise, and reverberation was tested with 40 subjects who varied in age and hearing level. Stimuli were 15 English vowels spoken in a (b-t) context in a carrier sentence, which were degraded by reverberation or noise (a babble of 12 voices). Vowel identification scores were correlated with various measures of hearing loss and with age. The mean of four hearing levels at 0.5, 1, 2, and 4 kHz, termed HTL4, produced the highest correlation coefficients in all three listening conditions. The correlation with age was smaller than with HTL4 and significant only for the degraded vowels. Further analyses were performed for subjects assigned to four groups on the basis of the amount of hearing loss. In noise, performance of all four groups was significantly different, whereas, in both quiet and reverberation, only the group with the greatest hearing loss performed differently from the other groups. The relationship among hearing loss, age, and number and type of errors is discussed in light of acoustic cues available for vowel identification.     

Variation in chick-a-dee calls of tufted titmice, Baeolophus bicolor: note type and individual distinctiveness

The chick-a-dee call of chickadee species (genus Poecile) has been the focus of much research. A great deal is known about the structural complexity and the meaning of variation in notes making up calls in these species. However, little is known about the likely homologous "chick-a-dee" call of the closely related tufted titmouse, Baeolophus bicolor. Tufted titmice are a prime candidate for comparative analyses of the call, because their vocal and social systems share many characteristics with those of chickadees. To address the paucity of data on the structure of chick-a-dee calls of tufted titmice, we recorded birds in field and aviary settings. Four main note types were identified in the call: Z, A, D(h), and D notes. Several acoustic parameters of each note type were measured, and statistical analyses revealed that the note types are acoustically distinct from one another. Furthermore, note types vary in the extent of individual distinctiveness reflected in their acoustic parameters. This first step towards understanding the chick-a-dee call of tufted titmice indicates that the call is comparable in structure and complexity to the calls of chickadees.     

RET receptor signaling: Function in development,metabolic disease,and cancer

The RET proto-oncogene encodes a receptor tyrosine kinase whose alterations are responsible for various human cancers and developmental disorders, including thyroid cancer, non-small cell lung cancer, multiple endocrine neoplasia type 2, and Hirschsprung’s disease. RET receptors are physiologically activated by glial cell line-derived neurotrophic factor (GDNF) family ligands that bind to the coreceptor GDNF family receptor α (GFRα). Signaling via the GDNF/GFRα1/RET ternary complex plays crucial roles in the development of the enteric nervous system, kidneys, and urinary tract, as well as in the self-renewal of spermatogonial stem cells. In addition, another ligand, growth differentiation factor-15 (GDF15), has been shown to bind to GFRα-like and activate RET, regulating body weight. GDF15 is a stress response cytokine, and its elevated serum levels affect metabolism and anorexia-cachexia syndrome. Moreover, recent development of RET-specific kinase inhibitors contributed significantly to progress in the treatment of patients with RET-altered cancer. This review focuses on the broad roles of RET in development, metabolic diseases, and cancer.     

Vocal fold nodules in adult singers: Regional opinions about etiologic factors, career impact, and treatment. A survey of otolaryngologists, speech pathologists, and teachers of singing

This study was undertaken to better understand current regional opinions regarding vocal fold nodules in adult singers. A questionnaire was sent to 298 persons representing the 3 professional groups most involved with the care of singers with vocal nodules: otolaryngologists, speech pathologists, and teachers of singing. The questionnaire queried respondents about their level of experience with this problem, and their beliefs about causative factors, career impact, and optimum treatment. Responses within and between groups were similar, with differences between groups primarily in the magnitude of positive or negative responses, rather than in the polarity of the responses. Prevailing opinions included: recognition of causative factors in both singing and speaking voice practices, optimism about responsiveness to appropriate treatment, enthusiasm for coordinated voice therapy and voice training as first-line treatment, and acceptance of microsurgical management as appropriate treatment if behavioral management fails.