A medical device with an implantable portion comprises, in part, an encapsulation sensor. In preferred embodiments, the encapsulation sensor comprises at least two electrodes and a circuit configured to sense impedance between the electrodes. Cell accumulation and fibrous capsule growth causes an increase...http://www.google.co.uk/patents/US20080081965?utm_source=gb-gplus-sharePatent US20080081965 - FOREIGN BODY RESPONSE DETECTION IN AN IMPLANTED DEVICE
