Naslov
New evidence on corticospinal tract behavior after repetitive stimulation of the motor cortex

Autori
Deletis, Vedran ; Išgum, Velimir ; Rodi, Zoran

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Electromyography and Motor Control, A Section of Electroencephalography and Clinical Neurophysiology / - : Elsevier, 1995, 195-196

Skup
Xth International Congress of Electromyography and Clinical Neurophysiology

Mjesto i datum
Kyoto, Japan, 15.10.1995. - 19.10.1995

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
transcranial electrical stimulation; motor evoked potentials

Sažetak
The development of methods to record motor evoked potentials (MEPs) from muscle elicited by short trains of stimuli applied over the motor cortex has raised dispute over 'optimal' stimulating parameters, partly due to changing excitability of cortical and spinal motoneurons during data acquisition, especially in anesthetized subjects. We have collected new data to address this issue. Transcranial electrical (c3/c4, up to 240 mA) or direct stimulation of motor cortex (up to 20 mA) was performed on 44 patients undergoing surgery of the spine/spinal cord or brain/brainstem. Corticospinal tract (CST) MEPs (D and I waves) were recorded from the epidural space of the spinal cord by catheter electrode placed cranially to the operated site, or in case of brain surgery, placed percutaneously. Simultaneous with epidural recordings, MEPs were recorded from the thenar and tibial anterior muscles. Our data showed that epidural MEPs to single stimuli could be used to optimize parameters for train stimulation to elicit MEPs from muscle. If a single stimulus generates multiple I waves following the D wave, the optimal interstimulus interval (ISI) must be long enough to prevent the second D wave from arising in the CST refractory period. If a single stimulus generates only a D wave, the limiting factor for ISI is recovery time of the D wave amplitude during repetitive stimulation. This recovery time was shorter when the duration of each stimulus in the train was 500 microseconds then for 100 or 200 microsecond stimuli. Finally, under certain conditions, two or three stimuli could facilitate the generation of an additional I wave which was not seen with single stimuli. Awareness of these factors is essential to optimally elicit MEPs over the muscle in anesthetized patients.

Izvorni jezik
Engleski

Znanstvena područja
Kliničke medicinske znanosti

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