Medical devices powered by the ear itself 
From: MIT Media Relations - 11/07/2012
By: Larry Hardesty

Deep in the inner ear of mammals is a natural battery - a chamber filled with
ions that produces an electrical potential to drive neural signals. In
11-08-2012 issue of the journal Nature Biotechnology, a team of researchers
from MIT, the Massachusetts Eye and Ear Infirmary (MEEI) and the Harvard-MIT
Division of Health Sciences and Technology (HST) demonstrate for the first
time that this battery could power implantable electronic devices without
impairing hearing.  

The devices could monitor biological activity in the ears of people with
hearing or balance impairments, or responses to therapies. Eventually, they
might even deliver therapies themselves. 

Read the entire article at:
http://web.mit.edu/press/2012/biological-battery-inner-ear.html

Links:
Konstantina Stankovic
http://www.masseyeandear.org/find-a-physician/details?physician_id=945074

Power from the ear
http://www.nature.com/nature/journal/v491/n7423/full/491162c.html

Energy extraction from the biologic battery in the inner ear
http://www.nature.com/nbt/journal/vaop/ncurrent/full/nbt.2394.html