Auditory Brainstem Implant

Electrode array inside cochlea

Nucleus Array In Situ - showing 22 channels safely placed in speech frequency range

The Auditory Pathway

Diagram showing relative positions of a cochlear implant andan auditory brainstem implant

Medial geniculate body

Inferiorcolliculus

Lateral lemniscus

Superior&accessory olive areaDorsal cochlearnucleusVentralcochlearnucleus

(Adapted from"Neurotology",Jacklerand Brackmann)

Cochlear

Auditory cortex

VIIIthnerve

CochlearImplant

AuditoryBrainstemImplant

Nucleus 24 Auditory Brainstem Implant

CI24M receiver-stimulator

Monopolarreference electrodes

(ball & plate)

Microcoiled electrodewires

Electrode array(21 platinum disks0.7mm diameter)

T-shapedDacronmesh

Removeablemagnet

Position of ABI in the Brainstem

ICP

OLIVE

PB

LM

ABI

CEREBELLUM

VIII

VII IX

VIPons Medulla

FlocculusPC

V.

Tumour

WPS / BLN

Position of ABI in the Brainstem

PenetratingAuditory Brainstem Implant

PABI ElectrodeABI Electrode

8.5mm

Electrode diameter:: 0.7mm

2

3

4

5

6

7

8

9

10

11

12

14

13

15

16

17

18

19

20

21

22

Penetrating ABI Location

Rikke Pedersen 20 y

ABI 24 Advantages and Benefits

• Optimizes stimulation using 21 distinct sites.

• Potential to Confirm placement using NRT.

• Widest choice of Coding strategies.

MRI Considerations

MRIStatic

Magnetic Field(1.5T)

Magnetic SwitchedGradients (20 T/s)

Radio Frequency (RF)

Energy(2-16KW peak

@ 64 MHz)

FORCE in Magnetic components

CURRENT in conductingcomponents

HEAT

Removal of Nucleus 24 ABI Magnet

Tests to Ensure Reliability

Impact Test

Tests to Ensure Reliability

Impact TestCochlear routinely conducts tests to ensure the reliability of our products. For example, the CI24M implant has undergone extreme impact testing to verify ruggedness by simulating a blow to the head of a T-ball travelling at 65.0km/h (40.4mph).Test rig: impact hammer with T-ball with a mass of 3.6 kg (7.9lb), dropped through 450mm (17.7in).

Nucleus 24 Auditory Brainstem Implant

CI24M receiver-stimulator

Monopolarreference electrodes

(ball & plate)

Microcoiled electrodewires

Electrode array(21 platinum disks0.7mm diameter)

T-shapedDacronmesh

Removeablemagnet