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System and Method for Selective Multi-site Microelectrode Recording

IP.com Disclosure Number: IPCOM000016587D
Publication Date: 2003-Jul-01

Publishing Venue

The IP.com Prior Art Database

Abstract

A recording microelectrode with a related system and method of use is provided. The microelectrode has a curved tip that records tissue within a circumferential proximity to a target site in the brain. The microelectrode is manipulated with handle guided using a depth control device. The microelectrode system is a combination of the recording microelectrode and a protective sheath for use in the lumen of an insertion cannula of a stereotactic frame or similar device.

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System and Method for Selective Multi-site Microelectrode Recording

Background & Summary

This invention relates to microelectrode recording systems used for functional neurosurgical procedures.�

Deep brain stimulation (DBS) is increasingly accepted as a viable treatment modality.� In particular, DBS applied to the thalamus for treatment of tremor was approved by the FDA in 1997.� Subsequently, other diseases, such as Parkinson’s disease, dystonia, and chronic pain have been identified as candidates for treatment with DBS.

Implantation of a lead for DBS generally involves the following preliminary steps: (a) anatomical mapping and (b) physiological mapping.� � Anatomical mapping involves mapping segments of an individual’s brain anatomy using non-invasive imaging techniques, such as magnetic resonance imaging (MRI) and computed axial tomography (CAT) scans.� Physiological mapping involves localizing the brain site to be stimulated.� Step (b) can be further divided into: (i) preliminarily identifying a promising brain site by recording individual cell activity with a microelectrode and (ii) confirming physiological stimulation efficacy of that site by performing a test stimulation with a macroelectrode.�

Microelectrode recording is generally performed with a small diameter electrode with a relatively small surface area optimal for recording single cell activity.� The microelectrode may be essentially a wire which has at least the distal portion uninsulated to receive electrical signals.� The rest of the body or wire of the microelectrode may be insulated.� The microelectrode functions as a probe to locate a promising brain site.� Since a number of attempts may be required to locate the precise target site, it is desirable that the microelectrode be as small as possible to minimize trauma when the microelectrode is placed into the brain, in some cases, multiple times.

Once a brain site has been identified, a macroelectrode is used to test that the applied stimulation has the intended therapeutic effect.� Once macrostimulation confirms that stimulation at the brain site provides the intended therapeutic effect, the macroelectrode is withdrawn from the brain and a DBS lead is permanently implanted at the exact site.

There are a number of commercially available microelectrode recording (MER) systems used in deep brain stimulation.� Such a system includes apparatuses for holding the microelectrodes in place and electronics that connect to the microelectrodes to enable cell recordings.� MER systems are sold by Alpha Omega Engineering (Nazareth, Israel), Axon (Union City, CA), Atlanta Research Group (Atlanta, GA), and Microrecording Consultants (Pasadena, CA).� The Alpha Omega and Axon systems appear to be among the most popular with functional neurosurgeons.� None of these companies manufacture their own microelectrodes, although they may provide a microelectrode as part of the MER system package.� The Fred Haer Corporation (FHC) markets a popula...