When does the robotic sound of a cochlear implant go away?

The short answer is about a year. The brain has to relearn how to hear emotion and tone from a low resolution signal. Emotion and tone are examples of indexical cues. CIs may sound "normal" after a year, but CIs don't provide enough information for hearing indexical cues as well as people with typical hearing.

What are Indexical Cues?

Cochlear implants (CI) have low resolution hearing. They're great for making out words in quiet. They're ok for making out speech in noise. They do not do well at reproducing all the other stuff in speech. This "other stuff" is called indexical information. Just a few examples of indexical information are:

• emotion
• tone
• dialect
• gender
• who is talking
• physical fitness
• social class

Indexical Cues Help You Read People Better

Indexical cues are an important part of "soft skills". These skills allow us to connect with others and work through relationship issues. Indexical cues are very important to understand what people really mean. Words can convey one meaning. Tone can mean the opposite.

Normal hearing people incorporate indexical cues and body language rapidly and on the fly. They do this seamlessly while they're hearing the words of what people say. This gives them the ability to "read others" and "read the room".

CIs Don't Communicate Indexical Cues Well

The information is still in the cochlear implant signal–it's just not very strong. It has little to do with the brand of cochlear implant. The auditory nerve doesn't do a good job at encoding pitch information.

At first, hearing indexical cues is sort of looking for a needle in a haystack. Over the next year, the brain learns how to hear this information. Once this happens, people think they're hearing "normally". But even after a year, it's still low resolution hearing. This never changes. People with CIs only hear half of indexical cues. Normal people can identify who's talking almost immediately. They can identify most emotion in voices. This is not a new finding.

In the real world, it's noisy and there are many subtle indexical cues. People may think that they are hearing tone when they are not. There are several places where this can break down.

• They cannot hear tone and other indexical cues if this is the only thing they are listening for.
• It's a processing issue. They can hear the indexical cues well enough. But because they're busy listening to the words, they don't process indexical cues well. In other words, people are working hard to hear with their cochlear implant. They can get "tunnel vision" and ignore important cues. This can be more of an issue with people who have been deaf for longer periods of time.
• People often try replace this information visually by reading facial expressions and body language. The skill of this varies widely. Even for people who are good at identifying cues, they may not process them.

How to Compensate and Read People Better

"Soft skills" or the ability to connect and work with other people well. These skills are important for relationships and careers. Since CIs don't communicate tone well, how do you compensate? It's important to realize that you may not notice body language unless you're intentional about it.

Take a step back in the conversation. You may be able to stop listening to the words of what people say. Think about their body language. Here are some tips:

• Are they leaning in with interest? Or are showing that they're less open with their folded arms?
• Do they make eye contact when talking? This signifies interest. Someone who is looking off in the distance and their voice is trailing may be thinking out loud or non-committal.
• Fidgeting or playing with hands or hair can suggest nervousness.
• Pursed lips can indicate skepticism or anger.

If you're in doubt of what a person means, it's great to say, "I'm hearing you say this. Is this accurate?" I sometimes directly tell a person, "I don't hear tone well, is this what you're meaning?"

Please contact us with your stories or tips!