EVALUATION OF OLFACTORY FUNCTION BY TOPOGRAPHIC EEG-ANALYSIS IN PATIENTS WITH PARKINSONS-DISEASE

Olfactory function impairment has been observed in patients with idiop athic Parkinson's disease (PD) using psychophysical procedures. In thi s study, an electrophysiological technique based on spectral analysis and topographic EEG mapping was used to evaluate EEG arousal response to olfactory stimulation in ten normal subjects and ten PD patients in stage II according to Hoehn and Yahr's scale, all of whom had akineti c-rigid syndrome and were receiving chronic L-Dopa therapy. Olfactory function was stimulated using diluted benzaldehyde by means of an appa ratus set up in our laboratory, Spontaneous and post-olfactory stimulu s EEGs were recorded from 20 electrodes placed upon the scalp accordin g to the Int. 10-20 System. Total EEG power (from 0.5 to 19.5 Hz) was evaluated over 10 sec, artefact-free epochs. Art olfactory arousal rea ction was detected in nine of the ten PD patients and was characterise d by a significant decrease ira total power similar to that observed i n all of the 10 normal subjects; these variations in EEG were found in all but the anterior regions of the scalp, The use of this technique does not seem to reveal any clear alteration in the olfactory function of PD patients.