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Absolute Pitch (AP) is commonly defined as a rare ability that allows an individual to identify any pitch by name. Most researchers use classificatory tests for AP which tracks the number of isolated correct answers. However, each researcher chooses their own procedure for what should be considered correct or incorrect in measuring this ability. Consequently, it is impossible to evaluate comparatively how the stimuli and criteria classify individuals in the same way. We thus adopted a psychometric perspective, approaching AP as a latent trait. Via the Latent Variable Model, we evaluated the consistency and validity for a measure to test for AP ability. A total of 783 undergraduate music students participated in the test. The test battery comprised 10 isolated pitches. All collected data were analyzed with two different rating criteria (perfect and imperfect) under three Latent Variable Model approaches: continuous (Item Response Theory with two and three parameters), categorical (Latent Class Analysis), and the Hybrid model. According to model fit information indices, the perfect approach (only exact pitch responses as correct) measurement model had a better fit under the trait (continuous) specification. This contradicts the usual assumption of a division between AP and non-AP possessors. Alternatively, the categorical solution for the two classes demonstrated the best solution for the imperfect approach (exact pitch responses and semitone deviations considered as correct).

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BACKGROUND: Absolute pitch (AP) is the ability to identify or produce isolated musical tones. It is evident primarily among individuals who started music lessons in early childhood. Because AP requires memory for specific pitches as well as learned associations with verbal labels (i.e., note names), it represents a unique opportunity to study interactions in memory between linguistic and nonlinguistic information. One untested hypothesis is that the pitch of voices may be difficult for AP possessors to identify. A musician's first instrument may also affect performance and extend the sensitive period for acquiring accurate AP. METHODS/PRINCIPAL FINDINGS: A large sample of AP possessors was recruited on-line. Participants were required to identity test tones presented in four different timbres: piano, pure tone, natural (sung) voice, and synthesized voice. Note-naming accuracy was better for non-vocal (piano and pure tones) than for vocal (natural and synthesized voices) test tones. This difference could not be attributed solely to vibrato (pitch variation), which was more pronounced in the natural voice than in the synthesized voice. Although starting music lessons by age 7 was associated with enhanced note-naming accuracy, equivalent abilities were evident among listeners who started music lessons on piano at a later age. CONCLUSIONS/SIGNIFICANCE: Because the human voice is inextricably linked to language and meaning, it may be processed automatically by voice-specific mechanisms that interfere with note naming among AP possessors. Lessons on piano or other fixed-pitch instruments appear to enhance AP abilities and to extend the sensitive period for exposure to music in order to develop accurate AP.

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Animals use honest signals to assess the quality of competitors during aggressive interactions. Current theory predicts that honest signals should be costly to produce and thus reveal some aspects of the phenotypic or genetic quality of the sender. In songbirds, research indicates that biomechanical constraints make the production of some acoustic features costly. Furthermore, recent studies have found that vocal features are related to genetic diversity. We linked these two lines of research by evaluating if constrained acoustic features reveal male genetic diversity during aggressive interactions in ocellated antbirds (Phaenostictus mcleannani). We recorded the aggressive vocalizations of radiotagged males at La Selva Biological Station in Costa Rica, and found significant variation in the highest frequency produced among individuals. Moreover, we detected a negative relationship between the frequency of the highest pitched note and vocalization duration, suggesting that high pitched notes might constrain the duration of vocalizations through biomechanical and/or energetic limitations. When we experimentally exposed wild radiotagged males to simulated acoustic challenges, the birds increased the pitch of their vocalization. We also found that individuals with higher genetic diversity (as measured by zygosity across 9 microsatellite loci) produced notes of higher pitch during aggressive interactions. Overall, our results suggest that the ability to produce high pitched notes is an honest indicator of male genetic diversity in male-male aggressive interactions.

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A relaçäo entre habilidades auditivas e aprendizagem, especialmente entre discriminaçäo auditiva e dificuldades na leitura e na escrita, é matéria controvertida, o que motivou a pesquisa apresentada neste artigo. Nela, foram estudados 23 alunos da primeira série escolar, separados em dois grupos, que se diferenciavam quanto ao rendimento escolar, e aos quais se aplicou prova de discriminaçäo auditiva para sons verbais

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Objetivo: comparar os escores do reconhecimento de fonemas em situação de silêncio e na presença de ruído competitivo (ruído branco, relação sinal/ruído de +10dB). Método: cinco crianças em idade escolar com deficiência auditiva neurossensorial pós-lingual de grau moderado até severo foram testadas utilizando um aparelho de amplificação sonora individual (AASI) analógico e um aparelho de amplificação sonora individual híbrido com múltipla memória e múltiplos canais. Resultados: não houve diferença entre os escores obtidos com a utilização do aparelho de amplificação sonora individual analógico e os obtidos com o aparelho de amplificação sonora individual híbrido, nas diferentes programações, para ambas situações avaliadas. Conclusão: na amostra avaliada recursos como a múltipla memória e compressão multicanal não melhoraram a performance de reconhecimento de fala no silêncio e na presença de ruído.

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The purpose of this study is to increase the knowledge of the spiral ganglion in relation to hearing, discrimination, normal deterioration of age, and other pathologies encountered in the study of the temporal bones. After a brief analysis of previous research on the spiral ganglion the author builds a model to study different available methods of assessign spiral ganglion population. Counting ganglion cells in one of each 10 section, 20 microns width seems to be the best method. From the collection of more than 900 temporal bones of Prof Schuknbecht at the Mass. Eye & Ear Infirmary, one hundred cases were selected. Ninety eight to these cases had a previous audiogram with discrimination priorto death. Pathology of these cases had been studied by Prof. Schuknecht. At the same time, some anatomical and hystological observations were made, studying the normal deterioration of the ganglion cells according to age, and its relation to hearing and discrimination. In relation to age, a linear deterioration from the first to the ningth decade of life was found uniformly distributed among the segments. The minimum number of cells necessary to preserve hearing was also determined. For instante, 22.000 cells are required for 10 dB or better hearing: 10.000 cells are necessary for 50 dB or better hearing. Although it is hard to relate ganglion cells to discrimination, it appears that to attain a PB Score of 80 percent or better, at least 18.000 cells are required. When comparing the number of ganglion cells of each segment with discrimination, a closer relation with the apical segment is apparent. The total number of cells and the number of cells in each segment of three normal subjects under 10 year of age was compared with the following cases: Under 80 years old, neural prebycusis, strial atrophy. Meniere's disease, otoesclerosis and middle age individuals with normal hearing. No significant variations among these pathologies were found. In contrast, guinea pigs with experimentally induced labyrinthine hydrosp showed and evident ganglion cell loss in the apical coil. Each of the findings of this study are discussed in relation to previous reports

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Cochlear implants have been designed to partially restore hearing to those people who are totally deaf. Multi-channel cochlear implants offer the opportunity to evoke acoustic perceptions like loudness and pitch, elicited by a controllable pattern of electric stimulation by means of electrodes placed in different places along the cochlear length. In this study, two psychophysical experiments were conducted with 4 patients, 1 prelingually and 3 postlingually-deafened, implanted with the multi-channel cochlear prosthesis Nucleus 22. Experiments were carried out to study the effect of varying the width of the electric biphasic pulsatile stimuli on the discriminative abilities of the pitch perception. The tests involved place pitch ranking and pulse rate discrimination. Place pitch ranking was studied by determining the just noticeable difference in pitch pairs (jnd-pp), defined as the pair of nearest electrodes which elicit different pitch perception. Pulse rate discrimination was studied by determining the just noticeable difference in pulse rate (jnd-pr) defined as the minimal difference in stimulus repetition rate over a given electrode, which elicits different pitch perceptions. Both experiments were conducted using pulses of 400, 200, 100 and 50 microseconds/phase. The results indicated that in spite of the differences in pathologies and personal histories, both jnd-pp and jnd-pr decrease by diminishing the pulse width. Speech perceptual data, measured for various pulse widths, validates the usefulness of decreased pulse width which yields favorable results in the psychophysical tests.

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The differences between schizophrenic patients with positive and negative symptoms have been the subject of extensive investigations. Psychophysiologists have proposed that there are elementary auditory sensory processing deficits in schizophrenia, but their prevalence in particular positive or negative subtypes has not been described. Our previous studies have shown that schizophrenics have impaired auditory sensory gating relative to normal controls, as demonstrated by the P50 auditory evoked potential conditioning-testing paradigm. In this paradigm, schizophrenics fail to show the normally expected diminished response to the second or 'test' stimulus. In the present study we assessed the possible relationship of this defect to negative symptoms in 20 schizophrenic patients treated with neuroleptics. Nine patients met the Andreasen criteria for predominantly 'negative schizophrenia'. 12 normal controls with no family history of schizophrenia were also studied electrophysiologically. Negative schizophrenics showed greater impairment than patients without such symptoms on the Trails B test of organic impairment, but there were no differences between groups on electrophysiological measurements of auditory sensory gating. Both schizophrenic groups showed impaired P50 auditory gating compared to normal controls. Both groups of schizophrenics also had a significantly diminished amplitude of the N100 waveform in the conditioning response, compared to normal controls. Auditory sensory processing defects in schizophrenia appear to be independent of negative symptoms.

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