Buss, Emily

Grose, John

Harris, Ashton

Carolina Digital Repository

Ipsilateral Masking Effects on Hearing Thresholds in AdultsAshton Harris, Emily Buss, and John GroseUniversity of North Carolina at Chapel Hill, NC, USABackgroundObjectivesMethods ResultsDiscussionReferencesIpsilateral masking can be defined as masking that is presented in the same ear as the target word. Clinicians can utilize ipsilateral masking in order to assess the effectiveness of a hearing aid or cochlear implant for listening in a noisy environment. Within ipsilateral masking, this research study examined the thresholds of hearing with informational and energetic masking. Informational masking occurs when a participant cannot focus on the target word because several words or conversations are being presented simultaneously. Typically, children are more susceptible to informational masking1. On the other hand, energetic masking occurs when a participant is unable to hear the target word due peripheral response to the noise swamping out response to the target. 1. Wightman, F. Informational Masking of Speech in Children: Effects of Ipsilateral and Contralateral Distracters. HeuserHearing Institute and Department of Psychological and Brain Sciences, 20052. Moore, B. Basic Auditory Processes Involved in the Analysis of Speech SoundsThe purpose of this research study was to aid audiologists in developing a clinical test for patients with hearing loss by analyzing the effect of masker level and masker type on word recognition in normal-hearing listeners Six undergraduate students were given a tympanogram and a hearing screening with extended high frequency headphones in a soundproof booth to ensure that the participants had normal hearing. Participants kept the high frequency headphones on and were instructed to select the image on an iPadof the word that they heard. We then estimated the threshold signal level associated with 71% correct word recognition. The two-talker masker tested for the effect of informational masking while the speech shape noise masker tested for the effect of energetic masking. The experiment was controlled using MatLab. The six conditions as follows were presented in a random order and the threshold values were recorded:Two-TalkerMaskerSSNMasker75 dB SPL 75 dB SPL60 dB SPL 60 dB SPL45 dB SPL 45 dB SPLThe SRT in dB SNR was relatively consistent despite a 30 dB difference in presentation level from 75 to 45 dB. There is a trend for thresholds to increase with increasing level in the noise masker (2 dB), and for better performance at 60 dB SPL than 45 or 75 dB SPL in the speech masker (3 dB). More data are needed to confirm these trends. The level effect in SSN is consistent with what we know about cochlear filtering. Though six participants is a small sample size, these results can serve as preliminary data for audiologists working with patients that have hearing loss. Audiologists can use this data as a reference for normal hearing in order to analyze how informational and energetic masking influences the threshold values for patients with hearing loss.Figure 1: Difference in Presentation of Energetic and Informational Masking A restricted frequency enables a participant to better identify the target sound. When a masker is presented at a lower frequency than the target sound, cochlear tuning becomes poorer2. As a result, the participant is not easily able to distinguish the target sound accompanied by a masker. A.B.C.Figure 2: Diagram explaining the audiometer and iPad setupFigure 3: Box-plot of SRT data in SSN and two-talker masker conditionsFigure 4: Box-plot with lines indicating data of one participant who was particularly susceptible to informational masking.Figure 52: Excitation patterns for a 1000 Hz sinusoid at levels ranging from 20 to 90 dB SPL in 10 dB steps

Ipsilateral Masking Effects on Hearing Thresholds in Adults

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Ipsilateral Masking Effects on Hearing Thresholds in Adults

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