title: A tripolar current-steering stimulator ASIC for field shaping in deep brain stimulation.
abstract: A significant problem with clinical deep brain stimulation (DBS) is the high variability of its efficacy and the frequency of side effects, related to the spreading of current beyond the anatomical target area. This is the result of the lack of control that current DBS systems offer on the shaping of the electric potential distribution around the electrode. This paper presents a stimulator ASIC with a tripolar current-steering output stage, aiming at achieving more selectivity and field shaping than current DBS systems. The ASIC was fabricated in a 0.35-μ m CMOS technology occupying a core area of 0.71 mm(2). It consists of three current sourcing/sinking channels. It is capable of generating square and exponential-decay biphasic current pulses with five different time constants up to 28 ms and delivering up to 1.85 mA of cathodic current, in steps of 4 μA, from a 12 V power supply. Field shaping was validated by mapping the potential distribution when injecting current pulses through a multicontact DBS electrode in saline.
authors.affiliation: Department of Electrical and Electronic Engineering, University College of London, London WC1E 7JE, UK. v.valente@ee.ucl.ac.uk
authors.forename: Virgilio
authors.initials: V
authors.lastname: Valente
authors.forename: Andreas
authors.initials: A
authors.lastname: Demosthenous
authors.forename: Richard
authors.initials: R
authors.lastname: Bayford
mesh_terms: D000669:Amplifiers, Electronic; D001698:Biomedical Engineering; D001921:Brain / Q000473:pathology; D003201:Computers; D046690:Deep Brain Stimulation / Q000295:instrumentation*; D011211:Electric Power Supplies; D004567:Electrodes, Implanted; D004581:Electronics; D004867:Equipment Design; D020342:Finite Element Analysis; D006801:Humans; D019736:Prostheses and Implants; D011846:Radio Waves; D012815:Signal Processing, Computer-Assisted; D059015:Wireless Technology