Nexstim Oy

Other

Nexstim Oyj

Nexstim

Jari Karhu

Jarmo Ruohonen

Risto Ilmoniemi

Juha Virtanen

Perttu Sipilä

Raine Hurme

The present publication discloses a device and method for generating magnetic pulses and directing them to brain. The device in accordance with the invention comprises means () for generating short, high energy current pulses (), means () for controlling amplitude () of the current pulses (), means () for generating high energy electromagnetic field stimulation pulses from the current pulses () and directing them to brain, and means () for measuring biologic responses to the stimulation pulses. In accordance with the invention the device includes means () for creating such a pulse sequence () of electromagnetic pulses where the amplitude () varies irregularly.

Magnetic stimulation device and method

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

The invention relates to a method for determining the effect of magnetic stimulation on human brain. According to the method, the stimulation dose is determined in different parts of the brain by summing cumulatively the electric field strength generated by the individual stimulus pulses. According to the invention, the position and alignment of a magnetic stimulation coil () is determined separately for each applied stimulus pulse in three dimensions relative to the head (), the number, repetition rate and intensity generated by the magnetic stimulation coil () are measured separately for each pulse, the coordinate data of the brain are determined substantially unambiguously in the same coordinate system with the magnetic stimulation coil () on the basis of information obtained from other kind of measurement, such as a tomographic scan or, e.g., a statistic database collected from a large number of patients, and the cumulative dose of electromagnetic radiation imposed on said desired point in the brain is determined on the basis of the location data available from the brain and the measurement data computed for the cumulative effect of the electromagnetic field evoked by said magnetic stimulation coil ().

Method and apparatus for dose computation of magnetic stimulation

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.

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Kuopio, Finland

Jari Karhu