Cochlear SPrint Sound Processor Informações Técnicas descarregar pdf (Página 47)

CLINICAL GUIDANCE | SECTION ONE

References

1. CP810/CR110 Validation, Cochlear internal data Aug 2009.

1.12.5 Autosensitivity

™

(ASC)

The function of the Autosensitivity control (ASC) is to automatically adjust the

microphone sensitivity based on the noise ﬂoor of the incoming acoustic signal.

If the noise ﬂoor is above a programmable breakpoint, it is likely that the gain

(sensitivity) is too high for that situation. In this case the ASC gradually reduces

the sensitivity. If the noise ﬂoor is below the breakpoint the gain is gradually

increased back to the manual setting. When using ASC, the microphone

sensitivity is automatically adjusted based on the noise ﬂoor of the surrounding

environment. The noise ﬂoor is the level to which sound decreases during breaks

in speech, also known as troughs. The ASC adjusts the microphone sensitivity

dynamically, and when the CP810/Freedom

™

ASC is set to default, it begins

to reduce the sensitivity when the measured noise ﬂoor in the acoustic signal

reaches 57 dB SPL. The overall perceptual effect of the ASC is a reduction in the

loudness of background noise. The programmable breakpoint is referred to as the

‘Auto-sensitivity Breakpoint’ and is by default set to 57 dB SPL for the CP810/

Freedom. This means that the autosensitivity function is activated (i.e. will start

turning down the sensitivity, once the background noise reaches 57 dB SPL. The

time taken for the ASC to adapt is in the order of seconds.

Figure 18:

Improvement of

speech perception

scores in noise with

CP810 using Zoom

compared with

CP810 and Freedom

using standard

microphone

directionality (no

Zoom).

100

Average

Freedom No Zoom

CP810 No Zoom

CP810 Zoom

*p<0.001

Testing in noise with zoom (n=15)

CUNY % 65 dB SPL - (S0, N90, 180, 270)

Percent correct

100

Freedom No Zoom

Average

CP810 No Zoom CP810 Zoom

Figure 2 Bars represent individual subject performance with each bar representing the average of eight lists measured over two sessions. The last three bars on the right

represent averages of all subjects’ performance, with error bars plotting the standard error of the mean. The asterisk indicates a statistically signiﬁcant difference.

*p<0.001

1 2 ... 42 43 44 45 46 47 48 49 50 51 52 ... 77 78

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