Introducers for implanting a lead having a fixation element distal to an electrode include a window, electrode, or conductive member alignable with the electrode of the lead white maintaining the fixation element in a retracted configuration. The window, electrode or conductive member of the introducer provide a mechanism for applying test stimulation signals to determine whether the lead is properly positioned in a patient without deploying the fixation element.

This document discusses, among other things, brain stimulation models, systems, devices, and methods, such as for deep brain stimulation (DBS) or other electrical stimulation. In an example, volumetric imaging data representing an anatomical volume of a brain of a patient can be obtained and transformed to brain atlas data. A patient-specific brain atlas can be created using the inverse of the transformation to map the brain atlas data onto the volumetric imaging data and a volume of influence can be calculated using the patient-specific brain atlas. In certain examples, the volume of influence can include a predicted volume of tissue affected by an electrical stimulation delivered by an electrode at a corresponding at least one candidate electrode target location.

A current generation architecture for an implantable stimulator device such as an Implantable Pulse Generator (IPG) is disclosed. Current source and sink circuitry are both divided into coarse and fine portions, which respectively can provide coarse and fine current resolutions to a specified electrode on the IPG. The coarse portion is distributed across all of the electrodes and so can source or sink current to any of the electrodes. The coarse portion is divided into a plurality of stages, each of which is capable via an associated switch bank of sourcing or sinking a coarse amount of current to or from any one of the electrodes on the device. The fine portion of the current generation circuit preferably includes source and sink circuitry dedicated to each of the electrode on the device, which can comprise digital-to-analog current converters (DACs).

In illustrative implementations of this invention, interferential stimulation is precisely directed to arbitrary regions in a brain. The target region is not limited to the area immediately beneath the electrodes, but may be any superficial, mid-depth or deep brain structure. Targeting is achieved by positioning the region of maximum envelope amplitude so that it is located at the targeted tissue. Leakage between current channels is greatly reduced by making at least one of the current channels anti-phasic: that is, the electrode pair of at least one of the current channels has a phase difference between the two electrodes that is substantially equal to 180 degrees. Pairs of stimulating electrodes are positioned side-by-side, rather than in a conventional crisscross pattern, and thus produce only one region of maximum envelope amplitude. Typically, current sources are used to drive the interferential currents.

A method for treating neural disorders is provided. The method includes the following operation. A stimulation is delivered to a layer of a cortex of a patient with a neural disorder, wherein the stimulation is delivered to less than all layers of the cortex of the patient. In another method for treating neural disorders, a stimulation is delivered to a cortex of a patient with a neural disorder, wherein the stimulation delivered to one of a plurality of layers of the cortex is stronger than to other layers of the cortex. The system for treating neural disorder is also provided. The system includes a stimulation signal generator and a layer-specific stimulation means. The layer-specific stimulation means is coupled to the stimulation signal generator, configured to deliver a stimulation to a specific layer of a cortex of a patient with a neural disorder.

Devices, systems, and techniques are described for adjusting therapy parameters defining electrical stimulation therapy delivered by multiple electrodes while maintaining a ratio of a value of a therapy parameter between the multiple electrodes. In one example, a device defines a relationship for multiple electrodes that defines a ratio of a value of a therapy parameter between the multiple electrodes. The device performs a master adjustment that adjusts each value of the therapy parameter for each respective electrode of the multiple electrodes by an amount specified by the relationship to maintain the ratio of the value of the therapy parameter between the multiple electrodes. The device controls delivery of electrical stimulation therapy according to the master adjustment.

A system for stimulation of a nucleus basalis of Meynert (NBM) of a patient includes an implantable electrical stimulation lead including electrodes and configured for implantation of at least one of the electrodes adjacent to or within the NBM of the patient; and an implantable pulse generator coupleable to the implantable electrical stimulation lead and configured for delivering electrical stimulation to the NBM through at least one of the electrodes of the implantable electrical stimulation lead, the implantable pulse generator including at least one processor configured to, upon user request, during an initial stimulation period, which is at least 1 month in duration and has a start and an end, increase over time at least one of a duration or an amplitude of the electrical stimulation from an initial value at the start of the initial stimulation period to a final value at the end of the initial stimulation period.

Methods for treating subjects afflicted with a psychiatric disorders [e.g., autism spectrum disorder (ASD), schizophrenia, and/or depression] are described herein. More particularly, the present invention relates to a method for treating a subject afflicted with or at risk for developing a psychiatric disorder (e.g., ASD, of which autism is a particular example) that calls for selecting a subject afflicted with or at risk for developing the psychiatric disorder based in part on previous in utero exposure to maternal immune activation (MIA) and treating the subject by administering pharmacological agents or implementing optogenetic tools or chemogenetic tools that correct dysregulated neuronal excitation/inhibition (E/I) ratios in cortical patches of the subject wherein the E/I ratio is dysregulated. A subject may also be selected for treatment using methods described herein based on the presence or detection of cortical patches having dysregulated neuronal E/I ratios.

Systems and methods for enhancing or affecting neural stimulation efficiency and/or efficacy are disclosed. In one embodiment, a system and/or method may apply electromagnetic stimulation to a patient's nervous system over a first time domain according to a first set of stimulation parameters, and over a second time domain according to a second set of stimulation parameters. The first and second time domains may be sequential, simultaneous, or nested. Stimulation parameters may vary in accordance with one or more types of duty cycle, amplitude, pulse repetition frequency, pulse width, spatiotemporal, and/or polarity variations. Stimulation may be applied at subthreshold, threshold, and/or suprathreshold levels in one or more periodic, aperiodic (e.g., chaotic), and/or pseudo-random manners. In some embodiments stimulation may comprise a burst pattern having an interburst frequency corresponding to an intrinsic brainwave frequency, and regular and/or varying intraburst stimulation parameters. Stimulation signals providing reduced power consumption with at least adequate symptomatic relief may be applied prior to moderate or significant power source depletion.

The present application relates to a new stimulation design which can be utilized to treat neurological conditions. The stimulation system produces a burst mode stimulation which alters the neuronal activity of the predetermined site, thereby treating the neurological condition or disorder. The burst stimulus comprises a plurality of groups of spike pulses having a maximum inter-spike interval of 100 milliseconds. The burst stimulus is separated by a substantially quiescent period of time between the plurality of groups of spike pulses. This inter-group interval may comprise a minimum of 5 seconds.