Confessions of an audiologist: Listening in a noisy restaurant

It was a friend’s birthday party and the setting was a nice restaurant that we hadn’t been to before. I was excited to meet friends I hadn’t seen in a long time. When we arrived, there were only four people at the table. We inquired after each other and shared the latest happenings while taking in the ambience of the restaurant. The restaurant itself was quite small, but tastefully decorated. We easily had the largest table with 13 settings, located in the center of the restaurant, and there were several other smaller tables of threes and fours. As the food arrived and the conversation started to flow, I noticed that the restaurant had, by then, become full.

It was probably a half hour into the meal when I suddenly became aware that I was having difficulty following conversations.  There were just too many to keep track of and even though people were talking louder to make themselves heard, it wasn’t cutting it. Fortunately, I was sitting next to my spouse and could hear what he was saying. I tried to carry on a conversation with my friend sitting next to me, but found it difficult to do so while other pieces of conversations floated into my awareness: my spouse referring to me in some conversation, a friend talking about her last vacation, another talking about her pregnancy. The waitress sauntered in and asked cheerfully, “Is everything OK?”

Well, everything was not OK (“Yes, thank you!”). I only wish I could’ve heard the conversations that I participated in better. My thoughts turned to the difficulty people with hearing loss must have in noisy restaurants. Here I was, a “young, normal hearing” person (as a hearing scientist might describe me), having a tough time. As a student clinician, if a hearing-impaired client were to have mentioned difficulty understanding speech in a restaurant setting, I would have imparted the following advice:

1. Request a seat away from potential sources of noise – like the kitchen, stage, or the bar
2. If possible, request a table that has good lighting, so you can see the person you are talking to
3. Sit facing to the person you would most like to talk to, so you can see his/her lips (and lip-read)
4. Ask for clarification when you miss parts of the conversation
5. Avoid peak times when the restaurant is busiest and most noisy

My experience had just proved that these tips, although based in sound reasoning, do not always work. Our table was away from the kitchen and the restaurant did not have a bar or stage. It wasn’t cutlery clattering, or the sound of muted music that was bothering me. The noise was what hearing scientists would call ‘competing speech’, i.e., speech from other talkers that wasn’t part of the ‘target’ conversation (loosely defined here as the conversation I was most interested in).

Listening in noise of any kind is a difficult task because the energy in the noise tends to inundate (mask) the target speech (i.e., energetic masking). Listening in competing speech involves much more than energetic masking. This is because competing speech is, well, also speech. It is therefore difficult to separate speech that we are interested in (target) from speech we are not interested in (masker). This type of masking is referred to as ‘informational masking’. Understanding speech is made more difficult by the fact that the ‘target’ keeps moving (literally). In the mix of six talkers, you may be attending to one talker at some point and then switch to a different talker. Every time I heard my name, or heard a reference to me or my spouse, the conversation which until then had been the background suddenly became the target.

There was plenty of lighting in the restaurant, so that really wasn’t an issue. I had better luck hearing my spouse, who was sitting next to me, than the birthday girl, who sat right across from me. I should clarify here that I am really poor at lip-reading.

I would not have hesitated from asking for clarification if it had been a smaller group. As things were, with 13 people and at least six conversations at any given time, I did not even entertain the idea of asking for clarification. I would have loved to schedule the dinner for a time when the restaurant was less busy, but come on – who am I kidding? It is impossible for friends to find time to get together these days, given our busy schedules. It was actually quite a miracle that so many of us could get together at the same time. And what fun is a birthday dinner that is held at 4 in the afternoon anyway?

When I related my experience to my parents, they chuckled knowingly. We shared experiences about conversations where we had each misheard in noisy situations and laughed about it. Even though we didn’t express it, each of us knew that although we were able to laugh about it now, it wasn’t at all funny when it happened.

How might a hearing aid user fare in such a listening situation? If he were to switch to the program with the directional microphone, then the microphone would pick up conversations emanating from directly in front of the user and turn down ‘background’ noise. However, we are not always facing the talker in situations like these. Someone sitting next to us or two tables down might enter into the conversation and it may take a while for us to realize that, determine who it is, and turn to face the new talker. This is more difficult when the conversation is fast-paced and there are multiple participants. So directional microphones, although generally useful, would help only to the extent that the target conversation emanates directly in front of the user.

The goal of noise reduction algorithms, present in modern digital hearing aids, is to enhance the signal-to-noise ratio (i.e., level of the speech relative to the level of the noise) by reducing the background noise. However, despite many advances in noise reduction technology, it is least effective when the background is competing speech.

Digital hearing aids also use compression to turn down loud sounds and make sure that sounds remain comfortable to the hearing aid user. However, although this feature will make sounds comfortable to the wearer, it is unlikely to help with speech understanding in the sort of listening situation described here. The use of FM systems may also help in such a situation, but is more useful in a more structured listening environment (e.g., classroom or conference setting). For example, an FM system may work better in a conference setting, where the microphone can be placed in the center of the table and speakers can pass around the microphone to others as they speak.

This is not to say that hearing aids are not helpful. Quite the contrary; you are much better off with your hearing aid than without it. What I do want to emphasize here, though, is that there are limits to what current hearing aids can do and it is important to realize those limits and set realistic expectations. Listening in competing speech is difficult even for people with normal hearing.  The ability to separate target speech from competing speech involves focusing on the target speech and ignoring the competing speech. You have to do this while also trying to make use of all the contextual information available, and if you can the visual cues from lipreading as well. In other words, listening in noise involves a lot of ‘top-down processing’, where you are using cognitive resources to enhance your understanding of ‘bottom-up cues’ (i.e., signal processed by your hearing aid, and by the ear). So successful understanding of speech in such noisy backgrounds depends not only on one’s auditory status, but also on their cognitive abilities.  In older adults, cochlear hearing loss may be accompanied by deficits in the central auditory system and cognitive declines.  A hearing aid by itself cannot address central and cognitive deficits, although it is able to address audibility. I would likely give similar advice to a hearing-impaired client today, but with the caveats I just mentioned. Food for thought…

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