Deep brain stimulation implant with microcoil array

#The present invention relates to deep brain stimulation (DBS) systems to treat certain medical conditions and, more particularly, to an implantable device having an array of selectively operable electromagnetic microcoils to induce currents in surrounding brain tissue.

#Over 50,000 Americans are diagnosed with Parkinson's disease each year, with more than half a million Americans affected at any given time. Conventional treatments include pharmaceutical agents that produce dopamine, a neurotransmitter, in an attempt to replenish the low levels found in the brains of those suffering from the disease. Approximately ten percent of people with Parkinson's disease initially treated with pharmaceutical agents have little to no response. Electrical stimulation of the brain presents an alternative treatment option.

#Specifically, deep brain stimulation has been used to effectively treat the symptoms of Parkinson's disease including rigidity, slowed movements, tremors, and walking difficulties. DBS treatment involves the surgical implantation of an electrical stimulator, often referred to as an electrode, lead, or implant, in the basal ganglia. Depending on the observed symptoms and treatment plan, DBS implants may be used to provide unilateral or bilateral simulation in the subthalamic nucleus (STN) or in the globus pallidus internus (GPi).

#FIG. 1 is a block diagram illustrating exemplary components of a DBS system including a neurostimulator and an implant with an array of microcoils in accordance with the present invention;

#FIG. 2 is an enlarged fragmented perspective view illustrating a distal end of the implant of FIG. 1;

#FIG. 3 is an enlarged plan view corresponding with the encircled region 3 of FIG. 2; and

#Referring initially to FIGS. 1 and 2, a deep brain stimulation system 10 includes a stimulator 12 coupled to an implantable device 14 (referred to hereinafter as an ‘implant’) with an array of planar electromagnetic microcoils 16. The stimulator 12 includes a pulse generator 13 that generates electrical pulses for delivery to a targeted stimulation site in a human brain 18 via the implant 14. The electrical pulses cause the microcoils 16 to produce magnetic fields that are directed perpendicularly into the brain 18. The magnetic fields, in turn, induce electrical currents in brain tissue to excite the neurons therein.

#The implant 14 is configured as an elongated insertion probe with a narrow cylindrical shaft 20 defining a longitudinal axis 21. The shaft 20 includes a proximal portion 22 with a connector 24 coupled to the stimulator 12 via a pair of leads 26 and a distal portion 28 with a plurality of spaced-apart microcoils 16. The implant 14 also includes a plurality of electrical conductors 30 (FIG. 3) and a ground layer 32 (FIG. 4) contained within the shaft 20. Each of the microcoils 16 is coupled to one of the electrical conductors 30 and to the ground layer 32.

#Upon implantation of the implant 14, the microcoils 16 are positioned in close proximity to a target stimulation site for delivery of magnetic field pulses to the brain 18. Like conventional DBS implants, the implant 14 can either provoke excitation of the brain 18 or momentarily disrupt function of specific cortical regions. Unlike conventional DBS implants that have direct, capacitive contact between metal electrodes and the adjacent brain tissue, the only portion of the implant 14 in direct contact with brain tissue is a biocompatible dielectric sheath, or coating 36 (FIG. 4). Thus, the microcoils 16 are electrically isolated from the surrounding brain tissue and there is no interface therebetween.