Electrical Impedance Properties of Deep Brain Stimulation Electrodes during Long-Term In-Vivo Stimulation in the Parkinson Model of the Rat - Biomedical Engineering Systems and Technologies - page 271

Fig. 8. In vivo impedance cha
counter-electrode over 12 days

ange of a unipolar Pt/Ir electrode measured against a dental-w
s ((a) Re = Z´; (b) Im = Z´´)

wire

Fig. 9. In vivo impedance cha
counter-electrode over 22 days

ange of a unipolar Pt/Ir electrode measured against a suture-
s ((a) Re = Z´; (b) Im = Z´´)

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4 Conclusions and d Perspectives

Pilot experiments in the ra
electrodes is significantly in
the formation of adhering t
a foreign body reaction. It
ciency can be improved w
tions of our own group hav
The use of platinum/iridium
The characterization of th
rized prototype stimulator s
stimulation duration. To the
chronic instrumentation of c
up to 3 weeks). Also for the
sonian rats for performing D

at model have shown that the impedance of unipolar D
ncreasing with time after implantation. The main reaso
tissue that encapsulates the implant. This tissue respons
ts intensity depends on the material. The stimulation e
with an appropriate electrode material. Previous investi
ve shown that stainless steel electrodes are not appropri
m could improve the stimulation efficiency.
he encapsulation process enabled us to readjust our mini
system to adapt the stimulation parameters according to
e best of our knowledge, we established for the first t
completely freely moving rats for long-term experiments
e first time, iron-free electrodes have been applied to Park
DBS experiments over the same observation time.

DBS
n is
se is
effi-
iga-
iate.

atu-
the
time
(of
kin-