What is hearing performance and why is it important?

Hearing performance is a measurement of how much communication benefit a recipient receives from their cochlear implant system.  It is measured in two ways – qualitatively and quantitatively.

Qualitative measurements of hearing performance are based on recipient feedback through questionnaires and diaries.  This type of measurement is important, but it is very subjective.  For example, what one recipient reports as excellent sound quality might not sound so good to another recipient.

Quantitative measurements of hearing performance involve controlled tests and specific numbers. For example, when your audiologist or researcher evaluates, via a designated test, a recipient’s ability to accurately identify recorded speech material in noisy and/or quiet situations.  A specific percentage is calculated based on what the recipient heard correctly.

Quantitative Tests - Demystifying the Hearing performance graphs

Before I explain some of the clinical trials Cochlear has conducted and their impact on hearing performance, I want to try to explain how to read and understand information on the graphs.  I’ll admit, it’s confusing…all of these numbers and abbreviations all over the place.  I hope I can take some of the mystery out of it for you.  First let’s start with some of the acronyms that you might see in these studies.

CUNY, CID,CNC – these are different word and sentence lists that were specifically designed for audiologist to determine which sounds you are hearing and which ones you aren’t.  CUNY and CID are sentence lists while CNC is a single word list.  Typically single word tests are more difficult than sentence tests.

dB – Decibel. The simple definition is a measure of loudness.  If you would like the more technical definition of what a decibel actually represents please let me know.

SPL – Sound Pressure Level.   This is an internationally accepted standard for measuring and stating the magnitude of sound.  In more basic terms, this is the loudness that the hearing test is being presented at.  So “60 dB SPL” means that all subjects within the test were listening to sounds/words/or sentences presented at a standard loudness of 60 dB.  

SNR – Signal to Noise Ratio.  This is used when testing word or sentence comprehension in background noise.  The phrase “+10 SNR” means, the speakers voice(signal) was 10dB louder than the noise. The phrase “-5 SNR” means; the speakers voice(signal) was 5 dB quieter than the noise presented.

N – often times you will see n=10, or n=32, n=56…etc.  N refers to the number of people that participated in the study.  The more people you have in your study (N) the higher confidence you have that your data represents the whole population.