Naslov
Identification of neurophysiologic markers generated by stimulation of motor speech related cortical areas

Autori
Rogić, Maja

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, pp prezentacija, znanstveni

Skup
21st Annual American Society of Neurophysiological Monitoring

Mjesto i datum
Nashville (TN), Sjedinjene Američke Države, 22.04.2010. - 25.04.2010

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Broca’s Area and Language - New Monitoring Method

Sažetak
Introduction One of the neurosurgical goals when operating within the brain eloquent areas is to preserve their function by avoiding motor speech deficits. A standard neurophysiologic method in achieving this goal is to locate the presumable motor speech related cortical areas by producing clinical effect of speech arrest while electrically stimulating these areas. However, only on the basis of clinical features it is difficult to distinguish speech arrest produced by stimulation of individual motor speech related cortical areas (Broca’s area, primary motor cortex for oro-pharyngeal-laryngeal muscles, negative motor areas: supplementary negative motor area and negative motor area). The final common organ for speech is the larynx and its muscles. Phylogenetically, in the speech development, laryngeal muscles become more specialized than other oropharyngeal muscles. Therefore, in our study we used them as a target organ from which we have recorded neurophysiologic markers generated by stimulation of motor speech related cortical areas. Methods, healthy subjects, and patients The study has been performed on three groups of subjects: a) group of healthy volunteers, b) patients preoperatively, c) patients intraoperatively. For the purpose of recording neurophysiologic markers from laryngeal muscles generated by stimulation of motor speech related cortical areas we have developed two methodologies: Transcranial magnetic stimulation (TMS), transcranial electric stimulation (TES), and direct cortical stimulation (DCS) of the motor speech related cortical area with recordings from: a)Vocal muscles (primarily in intubated patients under general anaesthesia) b)Cricothyroid muscles (primarily in awake patients/subjects but can be used in the patients under general anaesthesia) Stimulation The stimulation parameters for TES and DCS we used short train consisting of 3 to 5 stimuli with 0.5 ms duration each. For TMS two paradigm of stimulation we used: a) 20 stimuli with the frequency of 10 Hz, and b) 20 stimuli with the frequency of 1 Hz. Recording Anatomical landmarks for the placement of the hook wire electrodes in the cricothyroid muscle are determined according the methodology of Hirano & Ohala (1969). Before placement of electrodes in vocal muscle, patient was intubated and two electrodes are inserted through rigid laryngoscope. To record neurophysiologic markers from vocal and cricothyroid muscles, respectively, we used two hook wire electrodes, each consisting of Teflon coated wire 76 μm in diameter passing through 27 gauge size needles (0.4 mm) x 13 mm of length, Stainless Steel (hook wire electrodes, specially modified, Viasys Healthcare WI, MA, USA). The recording wires have a stripped Teflon isolation of 2 mm at their tip and curved to form the hook for anchoring them. Results We gave evidence that: (1) Stimulation of primary motor cortex (M1) for laryngeal muscles by using short train of high frequency stimuli, generates a short latency response (SLR) in vocal and cricothyroid muscles via corticobulbar pathway for vagal motor nuclei and recurrent and superior laryngeal nerve, respectively. (2) Stimulation of phonological part of Broca’s area (pars opercularis, Brodmann’s area 44) by using short train of high frequency stimuli, generates a long latency response (LLR) in vocal and cricothyroid muscles. (3) Stimulation with the 50-60 Hz of the both regions (M1 and phonological part of Broca’s area) generates tonic activity in the laryngeal muscles. A new achievement in identification of neurophysiologic markers generated by stimulation of motor speech related cortical areas could significantly contribute to their intraoperative anatomical and functional separation. Furthermore, neurophysiologic markers can give us new insight into speech and language physiology.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti, Kliničke medicinske znanosti

POVEZANOST RADA