Cochlear SPrint Sound Processor Informações Técnicas descarregar pdf (Página 19)

CLINICAL GUIDANCE | SECTION ONE

1.5 STIMULATION MODES

Electrical stimulation produces current ﬂow between an active (stimulated)

and indifferent (reference) electrode. A pair of electrodes forms a channel of

stimulation. For each channel, stimulation mode describes the location of the

indifferent electrode relative to the active electrode. The distance between

the two electrodes determines the spread of electrical current and the nerve

endings or spiral ganglia that are stimulated. There are two basic categories

of stimulation mode, monopolar and bipolar. The CI500 series implants,

Freedom™ implant as well as all Nucleus

24 implant models can use both

types. (Note: to access bipolar modes on the CI500 Series implants, you need

to use the Freedom Sound Processor or install the regional option to activate

this).

1.5.1 Monopolar (MP) Stimulation

In MP stimulation, the active electrode is inside the cochlea and the indifferent

electrode(s) is outside the cochlea. There are three MP conﬁgurations:

• Monopolar 1 (MP1): Current ﬂows between the active intracochlear

electrode and the ground ball electrode (Freedom and N24 series

implants). The CI500 series implants have a short pin-shaped electrode.

• Monopolar 2 (MP2): Current ﬂows between the active intracochlear

electrode and the plate electrode on the body of the implant (Freedom

and N24 series implants). On the CI500 series implants the extracochlear

electrode is built into the receiver stimulator.

• Monopolar 1+2 (MP1+2): Current ﬂows between the active intracochlear

electrode and both extracochlear electrodes.

The default stimulation mode is MP1+2. This mode produces the lowest

electrode impedances. MP modes also produce the lowest T- and C- levels.

This means that the implant uses less energy to produce stimulation and this

results in longer battery life. MP modes are necessary for higher stimulation

rates that are used in the Advanced Combination Encoder (ACE

™

/ACE(RE)) and

Continuous Interleaved Sampling Strategies (CIS/CIS(RE)).

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