1,720,979 research outputs found
Sordità infantile: epidemiologia, eziologia, prevenzione.
No full textLe ipoacusie infantili congenite preverbali rappresentano una rara evenienza (circa 1/mille nuovi nati all'anno) ma a causa delle gravi conseguenze sullo sviluppo del linguaggio devono essere identificate molto precocemente per una migliore recupero funzionale del paziente. Le considerazioni epidemiologiche ed eziologiche sulla ipoacusia congenita si riflettono sulle successive scelte in ambito protesico e riabilitativo
Argomenti di Audiologia
No full textQuesto manuale è principalmente indirizzato agli studenti che nel loro piano di studi devono affrontare materie con un “contenuto” audiologico. L’Audiologia ricopre un campo abbastanza ampio di conoscenze, provenienti da aree molto diverse: acustica, fisiologia, patologia, riabilitazione. Recentemente in Europa si è andato affermando un orientamento “medico” dell’Audiologia, tendente a dare maggior importanza ai rapporti fra aspetti tipicamente medici (diagnosi e terapia), aspetti tecnici (misure funzionali), conoscenze di base (area biologica). Questa impostazione ha, almeno nelle intenzioni, ispirato l’organizzazione ed il contenuto di questo manuale. Visto come raccolta di informazioni, il testo è stato suddiviso in parti e capitoli, all’interno dei quali sono stati individuati dei percorsi didattici. Questi, suggeriti dalla nostra esperienza e comunque modificabili, possono essere utilizzati dagli studenti provenienti da diversi indirizz
Clinical applicability of transient evoked otoacoustic emissions: Identification and classification of hearing loss
No full textThe study aimed at the development of a clinically applicable methodology that could: (1) discriminate transient evoked otoacoustic emission (TEOAE) recordings from normal hearing or hearing impaired individuals; (2) classify the nature of the hearing loss as conductive or as cochlear, and (3) define clear-cut TEOAE clinical criteria. A classification algorithm based on a multivariate discriminant analysis of fast Fourier transform data from recordings evoked by click stimuli of 50 +/- 2, 62 +/- 2, 68 +/- 2 and 80 +/- 2 dB SPL was used to discriminate 302 normal subjects from 383 subjects suffering from mild to moderate hearing losses. The best discriminant model (QDF80) produced a sensitivity of 93.8% and a specificity of 79.4%. When extra correlation criteria were serially applied to the classification outcome, the specificity was increased to 85.3%, but the sensitivity was marginally decreased to 91.7%. The classification of the correctly identified hearing-impaired cases yielded 93.8% identification of conductive and 75.1% identification of cochlear cases. A sensitivity analysis of the misclassified hearing-impaired cases suggested that the TEOAE spectra are well correlated with the 2-kHz but poorly correlated with the 4-kHz octave frequency
Miglioramento dell’intelligibilità verbale in condizioni audiovisive - Studio su soggetti ipoacusici.
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Threshold estimation in adult normal- and impaired-hearing subjects using auditory steady-state responses
No full textObjective: To compare the estimation of hearing threshold values from behavioral and electrophysiological (ASSR) methods, in subjects with normal hearing and sensorineural hearing impairment. In particular we were interested in estimating : (a) the error margin of the ASSR estimated threshold levels with a commercial instrument (Audera) ; and (b) how the ASSR estimated hearing levels depend on the degree of hearing loss. Methods: We have tested 32 subjects (17 male and 15 female) for a total of 61 ears. From those 11 (22 ears) presented normal hearing threshold values ( 0- 19 dB HL) and 21 (39 ears) sensorineural deficits. The latter group was subdivided in three classes namely : (i) 11 subjects (16 ears) with moderate hearing loss (53.7 dB HL ±12.3); (ii) 5 subjects (11 ears) with severe hearing loss (80.6 dB HL ±12.7); and (iii) 6 subjects (12 ears) with profound hearing loss (101 dB HL ± 5.5). Results: The data show that for the normal hearing subjects the ASSR threshold is approximately around 20 dB ( 11 dB SD) for the frequencies 0.25 – 1.0 kHz. For the higher frequencies the ASSR threshold increases up to 40 dB (12.5 dB SD) at 8.0 kHz. In our hearing impaired subjects also, we observed this phenomenon. In fact the ASSR proved to reliably predict the behavioral threshold (+/- 5 dB) especially in the group or most impaired ears. Similar errors were found in the less impaired ears, and for the ASSR at high frequencies. The regression analysis confirmed that the difference between the ASSR-estimated and behavioral threshold values, significantly decreases with the amount of hearing loss. Our data evidenced that for a 10 dB increment of the behavioral threshold, the ASSR threshold increases of 7 dB. The difference between the two methods, of about 27 dB observed in normal subjects tends to cancel in the hearing loss greater then of 95-100 dB HL. Conclusion: The results of our analyses indicate that the threshold estimates are rather discordant with the behavioral thresholds. Particularly, it seems that the correction factor we have applied does not rely on factors adequately modeled (instrumentation-wise) to compensate for the effects of hearing loss on ASSR thresholds. The threshold estimation is adequately modeled for high levels of hearing loss particularly for patients needing a cochlear implant.Background: The aim of the study was to compare the estimation of hearing threshold values by behavioral and electrophysiological (ASSR) methods in subjects with normal hearing and those with sensorineural hearing impairment. Material/Methods: Thirty-two subjects (17 male and 15 female) were tested, with a total of 61 ears. Of these, 11 (22 ears) presented normal hearing threshold values (0-19 dBHL) and 21 (39 ears) sensorineural deficits. Results: The data showed that for the normal-hearing subjects the mean ±SD ASSR threshold was approximately 20±11 dB for frequencies of 0.25-1.0 kHz. For higher frequencies the ASSR threshold increased to 40±12.5 dB at 8.0 kHz. Regression analysis confirmed that the difference between the ASSR-estimated and behavioral threshold values decreased significantly with the amount of hearing loss. The data showed that for a 10-dB increment of the behavioral threshold, the ASSR threshold increased by 7 dB. The difference of about 27 dB between the two methods observed in normal subjects tends to cancel in hearing loss greater than 95-100 dBHL. Conclusions: The results of these analyses indicate that the threshold estimates are rather discordant with the behavioral thresholds. in particular it seems that the correction factor applied here does not rely on factors adequately modeled (in terms of instrumentation) to compensate for the effects of hearing loss on ASSR thresholds. The threshold estimation is adequately modeled for high levels of hearing loss, particularly for patients requiring a cochlear implant. © Med Sci Monit, 2010
The McGurk phenomenon in Italian listeners
No full textIn the classic example of the McGurk effect, when subjects see a talker say /ga/ and hear a simultaneous /ba/, they typically perceive /da/, a syllable that was not presented either acoustically, either visually. This phenomenon, although non-natural and recreated in laboratory studies, has been studied in order to better understand how, where and when the central nervous system processes and integrates visual and auditory signals. Till now, it has been demonstrated for English, Spanish, German languages, while in Japanese and Chinese it seems weaker. Aim of this study was to evaluate the entity of the McGurk effect for the Italian language. Our results demonstrate a robust McGurk effect for the Italian language, which has never been described before. The phenomenon is highly significant when an auditory bilabial CV is dubbed with a visual apico-dental or velar CV. Results are discussed on the basis of recent hypothesis regarding the bimodal perception.In the classic example of the McGurk effect, when subjects see a speaker say /ga/ and hear a simultaneous /ba/, they typically perceive /da/, a syllable that was not presented either acoustically, or visually. This phenomenon, although non-natural and recreated in laboratory investigations, has been studied in order to better understand how, where and when the central nervous system processes and integrates visual and auditory signals. Till now, it has been demonstrated for English, Spanish and German languages, while in Japanese and Chinese it seems weaker. Aim of this study was to evaluate the entity of the McGurk effect for the Italian language. Results obtained demonstrate a robust McGurk effect for the Italian language, which has never been described before. The phenomenon is highly significant when an auditory bilabial Consonant-Vowel is dubbed with a visual apico-dental or velar Consonant-Vowel. Results are discussed on the basis of the recent hypothesis regarding the bimodal perception
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