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Noise Reduction Systems in Complex Listening Situations

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1.  What is selective attention? When you concentrate your attention on one target stimulus while suppressing others. When you concentrate your attention on two or more stimuli. When you focus on visual and auditory input at the same time. The inability to focus on what is important while blocking out the rest.

2.  What is divided attention? When you concentrate your attention on one target stimulus while suppressing others. When you concentrate your attention on two or more stimuli. When you focus on visual and auditory input at the same time. The inability to focus on what is important while blocking out the rest.

3.  What is a paired comparison test? Each stimulus has to be rated by pairs of at least two test people. Thus, the rating is very precise. A test person has to assign pairs of stimuli from all available stimuli. This yields the similarities between the stimuli. The test person has to compare two stimuli with regard to distinct dimensions like listening effort. This method can reveal small differences between the stimuli. It is a method to technically analyze a small number of stimuli by comparing them against each other.

4.  What is the Signal to Noise Ratio (SNR)? The level difference of target signal (i.e. speech) and background noise. A ratio higher than 0 dB indicates more target signal than noise. The accumulated level of target signal and noise. Both A & B

5.  What is the Hagerman Method using the phase inversion technique? An objective intelligibility estimation. A method to measure the output SNR of hearing aids. A subjective scaling method. A method used to measure the movement of the eardrum by laser holography.

6.  What is directional noise reduction? Gain in the hearing aids is reduced to prevent the ear from damage. Gain in the hearing aids is increased for better perception. Soundwaves coming from of a small area (typically in front of the subject) are amplified, whereas soundwaves from all other directions are attenuated. This gives a better SNR for the frontal direction. Noise coming from all directions is reduced significantly.

7.  What is the effect of directional noise reduction? Better speech intelligibility and increased listening effort. Less listening effort and reduced speech intelligibility. Less listening effort and better speech intelligibility. Effects of noise reduction are usually too small to measure.

8.  What are the dual task costs? A dual-task does not exist. Only one task can be performed at a time. Two or more tasks at the same time decrease the satisfaction of the test people/subjects. Our brain is optimized for two tasks at a time: vision and hearing are improved when both have to be done. Performance scores on two simultaneous tasks (dual task) are lower compared to a situation in which they are performed separately (single tasks).

9.  What is the cocktail party effect? The phenomenon of the brain's ability to focus to one talker (one auditory object) while suppressing other talking people (i.e. a typical selective attention scenario). Listeners have the ability to segregate different voices into different streams and decide which stream is most relevant to them. This is helpful at a cocktail party. The music often played at cocktail parties helps people to better discriminate different speakers talking at the same time. Both A & B

10.  What is the advantage of using complex listening situations for hearing aid tests? The remote control of the hearing aids can be tested at the same time. The complexity of handling the aids in those situations can be evaluated. The tests are close to the situations where users often report difficulties with their hearing aids. No statistically significant advantages were found yet.