Pediatric Noise: Theoretical Introduction

This video provides a discussion of the stimulus options available for pediatric testing and explains how PED noise is shaped.

Transcript

In this short video, we will explore some of the stimulus options available for pediatric testing. The standard stimulus used for audiometry is a pure tone. In most pediatric testing, a warble tone is preferred, as this is more interesting to the child. It is also essential in sound field testing to avoid standing waves.

A pure tone or a warble tone is highly frequency-specific, providing a very precise and controlled stimulus for testing. Another option is to use narrowband noise. This is more interesting than even a warble tone, and because it has a broader frequency spectrum, it stimulates more of the basilar membrane and is therefore more likely to elicit a response.

Unfortunately, the drawback of this is that we have a lot of spectral splatter across the frequencies, meaning that we have lost the precision of the pure tone or warble tone. In this example, presenting a 2 kHz narrowband noise stimulus is in fact stimulating such a wide range of the basilar membrane that we may be eliciting a response from a frequency region other than 2 kHz. This is particularly important to be aware of in cases of possible sloping hearing losses.

Pediatric or PED noise is a much better option than narrowband noise. It has a broader spectrum than the pure tone or warble tone, but much less so than narrowband noise, affording much greater frequency specificity.

As we can see in this sloping hearing loss example, the stimulus isn't going to be stimulating the normal-hearing region of the basilar membrane. This gives us more certainty and more accuracy in exactly what is being tested, while still providing a more interesting and engaging stimulus for the child compared with a pure tone or warble tone.

While pure tone stimuli offer the greatest frequency specificity and accuracy, they are generally not interesting enough for pediatric testing and should not be used for sound field testing. Warble tones can be more engaging to pediatric patients while retaining accuracy.

The broader frequency spectrum of narrowband noise makes it more interesting and more lifelike to pediatric patients, but any results recorded using this stimulus must be interpreted with caution due to the risk of off-frequency listening.

PED noise provides a solution to these issues. The stimulus is interesting enough to capture the child's attention, while minimizing the risk of off-frequency listening due to the narrower spectrum.