Effective Masking Levels for 500 and 2000 Hz Bone Conduction Auditory Steady State Responses in Infants and Adults With Normal Hearing
Notice bibliographique
Résumé
In Brief Objectives: Few studies have investigated effective masking levels (EMLs) needed to isolate the test ear for bone conduction assessments in infants. The objective of this study was to determine EMLs for 500 and 2000 Hz bone conduction auditory steady state responses (ASSRs) to amplitude (AM)/frequency-modulated (FM) stimuli for infants and adults with normal hearing. Maturational factors that contribute to infant–adult differences in EMLs will also be investigated. The present study and previously published 1000 and 4000 Hz EML data will be compared to investigate EML across four frequencies. These findings will provide a starting point for implementing clinical masking for infant bone conduction testing using physiological measures. Design: Participants were 15 infants (7 to 35 weeks) and 15 adults (21 to 56 years) with normal hearing. Bone-conducted single ASSR stimuli (research MASTER) were 100% AM and 25% FM at 85 and 101 Hz for 500 and 2000 Hz carrier frequencies, respectively. They were presented at 25 and 35 dB HL for 500 Hz and at 35 and 45 dB HL for 2000 Hz for both infants and adults (approximately 10 and 20 dB SL at each frequency for infants). Air-conducted narrowband maskers were presented to both ears simultaneously. Real-ear to coupler differences were measured to account for differences in the sound pressure developed in infant and adult ear canals as a result of ear-canal size. Data analyses were conducted for mean EMLs across frequency (500 to 4000 Hz) and between age groups. Masked and unmasked ASSR amplitudes were compared for 500 and 2000 Hz. Results: Both infants and adults required much more masking (25 to 33 dB) to eliminate responses at 500 compared with 2000 Hz. On average, infants required 16 dB more masking at 500 Hz and similar amounts of masking at 2000 Hz compared with adults. When adjusted for ear-canal size and bone conduction sensitivity, the pattern of results did not change. Across all four frequencies, infants showed a systematic decrease in mean EMLs with an increase in frequency; all pair-wise comparisons were significant except 2000 versus 4000 Hz. Adults showed smaller frequency-dependent changes in EML (only significantly greater for 500 versus 2000 Hz and 4000 Hz). When ear-canal size and bone conduction sensitivity were taken into account, only 500 Hz required more masking than other frequencies in infants; there were no significant frequency-dependent trends for adults, although the greater EMLs at 1000 versus 2000 Hz and 4000 Hz approached significance. Unmasked and masked amplitudes tended to be larger for 2000 Hz but not for 500 Hz when comparing infants with adults. Conclusions: EMLs appropriate for infants for bone conduction ASSRs elicited to AM/FM stimuli are considerably higher at 500 compared with 2000 Hz. Infants also need more masking at 500 Hz compared with adults but the same amount of masking at 2000 Hz. Comparisons across four frequencies reveal a systematic decrease in EML with an increase in frequency in infants, which is not apparent in adults. Recommended EMLs for AM/FM bone-conducted ASSR stimuli presented at 35 dB HL for 500, 1000, 2000, and 4000 Hz, respectively, are: (1) infants: 81, 68, 59, and 45 dB SPL, and (2) adults: 66, 63, 59, and 55 dB SPL. Clinical masking is not used routinely for either bone conduction auditory brainstem or auditory steady state response (ASSR) testing in infants, partly because effective masking levels (EMLs) have not been determined. EMLs for 500 and 2000 Hz bone conduction auditory steady state responses were investigated for normal-hearing infants and adults and compared with previously published EMLs for 1000 and 4000 Hz stimuli. Our findings indicated that more masking is needed at 500 versus 2000 Hz independent of age, and that infants require more masking at 500 but similar amounts at 2000 Hz compared with adults. On the basis of these and previous findings, recommended EMLs for 500 to 4000 Hz are proposed.
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Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
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