Exam Preview for 18777: The Value of Increasing the Number of Chann

The Value of Increasing the Number of Channels and Bands in a Hearing Aid

Please note: exam questions are subject to change.

1. What is the relationship between number of channels and group delay? the more channels, the shorter the group delay the more channels, the longer the group delay number of channels has no affect on group delay the relationship between number of channels and group delay is unknown
2. According to the research presented, how many bands provide acceptable frequency shaping flexibility for flat or gently sloping hearing loss? one two three four
3. For steeply sloping hearing losses, how many bands are required for adequate frequency shaping flexibility, according to the authors? two bands (low frequency, high frequency) three bands (low/mid/high) one band the research is unclear, but it may be close to 7 bands
4. Woods and colleagues (2006) found the number of hearing aid channels that would maximize predicted speech intelligibility for most audiograms to be: two three six nine
5. Kates (2010) found that increasing the number of channels from 3 to 18 resulted in: significantly improved speech audibility for a steeply sloping hearing loss, but no benefit for flat hearing loss significantly improved speech audibility for flat hearing loss, but worsened speech audibility for steeply sloping hearing loss significantly improved speech audibility for all hearing loss configurations (steeply sloping, rising/reverse, flat) no effect on speech audibility for all hearing loss configurations
6. Based on the research, the authors suggest that for restoring frequency-specific audibility, how many channels are required? 3 channels for flat or mildly sloping hearing loss; 9 to 18 channels for steeply sloping hearing loss 2 channels for flat or mildly sloping hearing loss; 4 channels for steeply sloping hearing loss 18 channels for flat or mildly sloping hearing loss; 3 channels for steeply sloping hearing loss 2 channels, regardless of the shape of the hearing loss
7. According to the research, increasing the numbers of channels would have what effect on noise reduction and feedback cancellation? Increasing the number of channels should improve effectiveness of noise reduction and feedback cancellation, but the relationship has not been investigated. Increasing the number of channels negatively impacts effectiveness of noise reduction and feedback cancellation Increasing the number of channels has no effect on noise reduction and feedback cancellation Increasing the number of channels improves the effectiveness of noise reduction but has a detrimental effect on feedback cancellation
8. Woods and colleagues (2010) investigated the effect of multi-channel directivity on speech recognition. Their findings suggest: 8 channels of directionality is ideal for maximizing speech recognition 16 channels of directionality is ideal for maximizing speech recognition 20 channels of directionality is ideal for maximizing speech recognition 256 channels may provide significant benefit as compared to 16 or 32 channels
9. Group delay refers to: the amount of time required for sound to pass through the auditory system the amount of time required for a hearing aid to process sounds the amount of current drain on a button cell battery the amount of time required for programming a hearing aid with multiple features
10. A general conclusion that can be drawn from this article is: When it comes to bands and channels, more is always better Hearing aids with more bands and channels will result in noticeably better sound quality and audibility, and more effective signal processing (digital noise reduction, directionality, feedback cancellation) than those with fewer bands and channels. The research does not support the claim that "more is always better" when it comes to bands and channels. As long as group delay is less than 5 msec there are no disadvantages to increasing bands and channels.