Cochlear SPrint Sound Processor Información técnica descargar pdf (Pagina 17)

CLINICAL GUIDANCE | SECTION ONE

1.4 ELECTRICAL STIMULATION AND MAP PARAMETERS

• Stimulation Mode – describes the location of the indifferent electrode

relative to the active electrode.

• Stimulation Rate – the frequency (Hz) of the biphasic current pulse

delivered to a channel. The clinician uses the software defaults or

alternatively selects a stimulation rate.

• Total Stimulation Rate (TSR) – the rate across the entire electrode array

for a stimulation cycle. It is the product of the per channel stimulation rate

and the number of maxima (SPEAK and ACE) or number of channels (CIS).

Example: 1,200 Hz stimulation rate x 12 maxima = 14, 400 Hz TSR.

• Sound Coding Strategies – a set of rules that deﬁne how the sound

processor analyses acoustic signals and codes them for delivery to the

cochlear implant. The default strategy for most processors is Advanced

Combination Encoder (ACE).

• Maxima – the frequency ranges in the audio signals that contain the

greatest amounts of energy. This is a parameter of the SPEAK and ACE

sound processing strategies.

• Frequency Allocation Tables (FATs) – deﬁne the frequency range

(frequency bandwidth) that is assigned to each active channel in the

MAP. Each channel covers a speciﬁc frequency range and a given channel

receives stimulation when its bandwidth has sufﬁcient energy in it

to be selected as a maxima. The FAT used depends upon the sound

processing strategy and the number of channels in the MAP. The software

automatically assigns the default FAT but the clinician can modify this.

Changing the FAT may affect sound quality.

• Channel Gain – the amount of ampliﬁcation applied to each channel

before output stimulation levels are sent to the implant.

• T-SPL – a MAP parameter that controls the minimum intensity input level

that results in electrical stimulation. Reducing the T-SPL results in softer

input signals being presented at the recipient’s T-level.

• C-SPL – a MAP parameter that controls the maximum intensity input

level that results in electrical stimulation at C-level (prior to the activation

of the AGC).

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Cochlear SPrint Sound Processor Información técnica Pagina 17