Other

Nexstim Oy

Neuromag Oy

Nexstim

Risto Ilmoniemi

Jarmo Ruohonen

Juha Virtanen

Jari Karhu

Raine Hurme

Perttu Sipilä

Marko Ollikainen

Seppo Ahlfors

Janne Kamppuri

An error in the co-registration of a coordinate system used to represent a head of a subject in image data with a coordinate system used to represent the location of trackers affixed to the scalp surface of the head and a tracked device, such as a transcranial magnetic stimulation ('TMS') induction coil device, is corrected using information representative of the actual distance between the tracked device and the scalp of the subject, such that representations of the tracked device and the subject's head are accurately shown on a display of a navigated brain stimulation ('NBS') system tracking movement of the tracked device in relation to the subject's head. The correction of the error in the co-registration is performed without collecting additional tracking information from trackers on a tracked TMS coil device and the head, which avoids interrupting NBS using the TMS coil device.

Method and apparatus for correcting an error in the co-registration of coordinate systems used to represent objects displayed during navigated brain stimulation

Disclosed is a method for producing a magnetic stimulation effect and/or a fake magnetic stimulation effect in a biological tissue. According to the method, the real magnetic stimulation is effected by virtue of inducing an electromagnetic field in said biological tissue with a sufficiently strong field strength to essentially excite said tissue, and the fake magnetic stimulation is effected by virtue of inducing an electromagnetic field in said biological tissue with a field strength that is weaker than the electromagnetic field required for an essential excitation of said tissue. According to the invention, said electromagnetic field weaker than the electromagnetic field strength required for an essential excitation of the tissue is produced by the steps of inducing at least one first electromagnetic field in said biological tissue and, simultaneously, inducing at least one second electromagnetic field superimposed with said first electromagnetic field but so deviated by its direction from the direction of said first electromagnetic that the sum effect of said electromagnetic fields in the target area of said biological tissue remains weaker than the electromagnetic field required for an essential excitation of said tissue. Also an apparatus is described suited for implementing the method.

Method for producing illusory magnetic stimulation

The present invention relates to a stimulator head of a magnetic stimulator used in the stimulation of living tissue such as the human brain. Such a stimulator bead comprises a stimulator head body ( ) suited for mounting the stimulator head on the magnetic stimulator equipment, at least one coil ( ) which is connected to said stimulator head body ( ) and is designed suitable for generating a stimulating magnetic field, and conductors ( ) for passing electric current from said magnetic stimulator into any of said at least one coil ( ). According to the invention, the stimulator head includes a housing ( ) which is connected to said stimulator head body ( ) and is designed to enclose at least one air-tight space ( ) which further separates each of said at least one stimulator coil ( ) from the other parts of said housing ( ) facing the object being stimulated. Further according to the invention, each of said at least one coil ( ) is placed in said housing ( ), whereby an acoustic insulation can be attained between each of said at least one coil ( ) and the object being stimulated by virtue of bringing the pressure in said air-tight space ( ) to a substantially low level.

Stimulator head and method for attenuating the sound emitted by a stimulator coil

The invention relates to a method and apparatus for examining and mapping the reactivity of and connections between different cortical areas. In the method an electromagnetic stimulus is induced in the interior parts of the head and the electromagnetic field generated around the skull is measured by electrical means (1). According to the method, the electromagnetic activity of the brain is measured using multichannel equipment, artefacts caused by the stimulus are eliminated from the signal containing the electromagnetic activity, a visualization of the activity changes in the measured signals is formed, and the areas of the head related to said activity generating said electromagnetic field are localized, or alternatively, the maximum of the sensitivity pattern of the multichannel activity measurement system is focused to a desired point.

Method and apparatus for mapping cortical connections

Method and apparatus for separating the different components of evoked

A method and apparatus for finding the location of electrodes attached to a body, particularly to the head is provided with at least one first coil arranged in conjunction with each electrode. The coils of the electrodes form a coil group to be localized. A plurality of other coils are arranged in the vicinity of the electrodes so that the position of the coils is uniquely known. The second set of coils forms a fixed coil group. A magnetic field is induced in at least a part of either the first coil group or the second coil group. The set of coils not generating the magnetic field are used for detecting the induced magnetic field. The measured results from the group of coils acting as a magnetometer are used to determine the position of electrodes. Using this implementation, the positions of the electrodes can be determined in a quick and accurate manner.

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Espoo, Finland

Risto Ilmoniemi