COMPUTER-AIDED IDENTIFICATION OF CORTICAL ELECTRICAL ACTIVITY IN PATHOLOGICAL TREMOR

Magistrsko delo opisuje postopek analize povprečij elektroencefalogramov (EEG) pri bolnikih s Parkinsonovo boleznijo in esencialnim tremorjem. Izračun povprečij smo fazno zaklenili na prožilne trenutke motoričnih enot, ki smo jih razpoznali iz površinskih elektromiogramov (EMG) ekstenzorjev in fleksorjev zapestja. S tem smo zmanjšali občutljivost signalov EEG na zunanje motnje. Izračunana povprečja signalov EEG smo vstavili v orodje Statistical Parametric Mapping in v njem s pomočjo inverzne projekcije ocenili aktivnosti različnih možganskih centrov. Analiza rezultatov je pokazala, da sta pri obeh skupinah pacientov aktivna predvsem dva možganska centra. Prvi se nahaja na področju predmotoričnega korteksa, drugi pa na področju senzomotoričnega korteksa. Statistična primerjava aktivnosti obeh centrov je razkrila signifikantne razlike v energiji osnovne frekvence tremorja in energiji njenega prvega višjega harmonika, predvsem pri bolnikih s Parkinsonovo boleznijo.We describe the analysis of multichannel electroencephalographic (EEG) signals recorded from patients with Parkinson\u27s disease and essential tremor. First, the averaging of EEG signals was phase-locked to the discharges of individual motor units that were identified from high-density surface electromyograms (hdEMG) of wrist extensors and flexors. This reduced the noise and artefacts in EEG signals and revealed their tremorogenic components. Calculated averages of EEG signals were then inserted into the Statistical Parametric Mapping (SPM) tool, where the activities of different cortical centers were estimated. Two cortical centers were consistently active in both groups of patients. The first one was located in the area of premotor cortex and the other in the area of sensorimotor cortex. Statistical comparison of those two centers revealed a significant difference in the energy of the basic tremor frequency and the energy of its first higher harmonic in patients with Parkinson’s disease