Evaluation of thalamocortical impulse propagation in the akinetic Rigd type of Parkinson's disease using high-frequency (600 Hz) SEP oscillations.
Human median nerve somatosensory evoked potentials exhibit low-amplitude, high-frequency (600 Hz) oscillations (HFOs) superimposed onto the primary cortical response 'N20.' Previous EEG-studies indicated the HFOs to reflect in part activity generated at the thalamus and within the thalamocortical radiation. Expecting impairment of thalamocortical impulse propagation in Parkinson's disease (PD) the present study aimed to explore the performance of the HFOs in a cohort of PD patients in comparison to an exactly age- and sex-matched group of controls. To avoid motor interference and to minimize the influence of central tremor oscillators to the HFOs we selected PD patients suffering from an akinetic rigid type of the disease. We recorded multichannel somatosensory evoked potentials and applied an advanced analysis combining source and time frequency analysis. Low frequency and HFO signals showed no significant differences between PD patients and the control group, neither in the source waveforms evaluation nor in the time frequency analysis. Contrasting two former studies indicating enhanced HFOs in nonselected PD patients the present results differ most probably due to the lack of motor interference effects and the missing impact of central tremor-oscillators on the signals by selecting patients without tremor.
Sensory systems.


OBJECTIVE
Somatosensory cortex and thalamocortical relationships.
Gobbelé
René
R
Department of Neurology, University Hospital Aachen, Germany. rgobbele@ukaachen.de
Thyerlei
Dinah
D
Kawohl
Wolfram
W
Buchner
Helmut
H
Waberski
Till Dino
TD
D001921:Brain / Q000503:physiopathology*; D004569:Electroencephalography; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology*