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[attachment=8172]

By Anu Jimmy

Abstract
A device, which is being designed by JOHNS HOPKINS SCHOOL OF MEDICINE,BALTIMORE,USA.
A neuro-electronic prosthesis for sensing head rotation in 3D & delivers stimuli
1.pulse frequency modulated,
2.biphasic ,
3.constant current stimuli.
upto eight electrodes & stimulates ampullary branches of vestibular nerve.
Head mounted, semi-implantable prosthesis
To restore AVOR:-gaze restoring mechanism

Anatomy of Inner Ear
3 Semi-circular canals(SCC):-fluid acts as inertial load for detection of component abt the axis perpendicular to its planes.
Utricle & Saccule- transduces translational acceleration
Fluid movement distorts CUPULA->shear stresses bending stereocilia->modulating neurotransmitter releases from hair cells->modulating firing rates of afferent nerves synapsing with hair cells.
6 SCC’s->3 pairs-RALP pair, LARP pair & HORIZONTAL pair

Causes of damage to vestibular sensation
Vestibular hair cells are injured due to
1. Ménière's disease
2.Ototoxic medications-Gentamicin
3.Surgical trauma during cochlear implantation

Circuit Details
6 IMPORTANT Components
Sensors
Processors
Current Source & switching
power
Software

Parameters
Intensity of pulse-charge withdrawn or injected the surrounding tissue
To control charge- we may control pulse current or duration or both.
Total injected current must be within the “safe stimulation range” for a given electrode.
Current should not exceeed the ratio of stimulator’s compliance voltage to electrode impedance.

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