Auditory Feedback Control of Vocal Pitch during Sustained Vocalization: A Cross-Sectional Study of Adult Aging

Background: Auditory feedback has been demonstrated to play an important role in the control of voice fundamental frequency (F0), but the mechanisms underlying the processing of auditory feedback remain poorly understood. It has been well documented that young adults can use auditory feedback to stabilize their voice F0 by making compensatory responses to perturbations they hear in their vocal pitch feedback. However, little is known about the effects of aging on the processing of audio-vocal feedback during vocalization. Methodology/Principal Findings: In the present study, we recruited adults who were between 19 and 75 years of age and divided them into five age groups. Using a pitch-shift paradigm, the pitch of their vocal feedback was unexpectedly shifted 650 or 6100 cents during sustained vocalization of the vowel sound/u/. Compensatory vocal F0 response magnitudes and latencies to pitch feedback perturbations were examined. A significant effect of age was found such that response magnitudes increased with increasing age until maximal values were reached for adults 51–60 years of age and then decreased for adults 61–75 years of age. Adults 51–60 years of age were also more sensitive to the direction and magnitude of the pitch feedback perturbations compared to younger adults. Conclusion: These findings demonstrate that the pitch-shift reflex systematically changes across the adult lifespan. Understanding aging-related changes to the role of auditory feedback is critically important for our theoretica

Human Auditory Cortical Activation during Self-Vocalization

During speaking, auditory feedback is used to adjust vocalizations. The brain systems mediating this integrative ability have been investigated using a wide range of experimental strategies. In this report we examined how vocalization alters speech-sound processing within auditory cortex by directly recording evoked responses to vocalizations and playback stimuli using intracranial electrodes implanted in neurosurgery patients. Several new findings resulted from these high-resolution invasive recordings in human subjects. Suppressive effects of vocalization were found to occur only within circumscribed areas of auditory cortex. In addition, at a smaller number of sites, the opposite pattern was seen; cortical responses were enhanced during vocalization. This increase in activity was reflected in high gamma power changes, but was not evident in the averaged evoked potential waveforms. These new findings support forward models for vocal control in which efference copies of premotor cortex activity modulate sub-regions of auditory cortex

Processamento auditivo em gagos: análise do desempenho das orelhas direita e esquerda Auditory processing in stutterers: performance of right and left ears

OBJETIVO: Comparar a diferença entre as orelhas nos testes comportamentais do processamento auditivo e os resultados de sujeitos com diferentes graus de gravidade de gagueira em cada teste do processamento auditivo. MÉTODOS: Cinqüenta e seis indivíduos, com idades entre quatro e 34 anos, foram encaminhados pelo Ambulatório de Avaliação Fonoaudiológica da UNIFESP para avaliação comportamental do processamento auditivo. Todos os pacientes foram submetidos à avaliação de audição, fala e linguagem. A disfluência foi classificada segundo o protocolo de Riley (1994), o qual prevê os seguintes graus de gravidade da gagueira: muito leve, leve, moderado, severo e muito severo. Os testes para avaliação do processamento auditivo foram selecionados e analisados de acordo com a idade do paciente e a proposta de Pereira & Schochat (1997). RESULTADOS: Observamos prevalência da gagueira de grau leve nas faixas etárias de quatro a sete anos e de 12 a 34 anos de idade, e de grau moderado nos indivíduos de oito a 11 anos de idade. Dos 56 indivíduos avaliados 92,85% apresentaram alteração do processamento auditivo. Houve diferença estatisticamente significante entre as orelhas direita e esquerda na etapa de atenção direcionada do teste dicótico não verbal, em todas as faixas etárias estudadas. Não foram encontradas diferenças significativas entre os graus de gravidade da gagueira em nenhum dos testes de processamento auditivo. CONCLUSÕES: A orelha direita apresentou melhor desempenho do que a esquerda nos diferentes testes comportamentais. O grau de gravidade da gagueira não interferiu no resultado de cada teste.<br>PURPOSE: To compare the difference between the performances of right and left ears in behavioral tests of auditory processing and to compare the results obtained by subjects with different stuttering severity classifications in each auditory processing test. METHODS: Fifty six subjects (49 male, 7 female), with ages ranging from four to 34 years, were referred to auditory processing evaluation as a complement to speech and language evaluation. All subjects were submitted to auditory, speech and language evaluation. Disfluency severity was classified according to the Riley Stuttering Severity Index as: very mild, mild, moderate, severe and very severe. Behavioral auditory processing tests were selected and analyzed regarding the patients' age and following the proposal of Pereira & Schochat (1997). RESULTS: Mild stuttering was prevalent among subjects with ages ranging from four to seven years and from 12 to 34 years. Moderate stuttering was the most prevalent degree among subjects with eight to 11 years old. Auditory processing disorders were observed in 92,85% of the subjects tested. Significant statistical differences between left and right ears were found in directed attention conditions for the nonverbal dichotic test, in all age ranges. No differences were found among subjects with different stuttering severity classifications in any of the auditory processing tests carried out. CONCLUSIONS: Right ear showed better results than left ear in both monotic and dichotic tests. Stuttering severity didn't interfere with the results of each test