[A novel approach to differential diagnosis of Parkinson's disease and essential tremor]

To study tremor and olfactory dysfunction in patients with Parkinson's disease (PD), patients with essential tremor and healthy people for the differential diagnosis and to verify the hypothesis on the inverse dependence between tremor and olfactory dysfunction.

Olfactory dysfunction was studied in 45 patients with PD, 40 patients with essential tremor and 64 healthy controls. Tremor was studied in 90 people, including 30 controls and 30 patients with PD and essential tremor. The olfactory function was tested with Sniffin' Sticks test. Tremor parameters were studied with wireless monitoring instrument for electrophysiological signals record, where three essential data flows have been recorded: electromyogram, gyroscope and acceleration. The instrument recorded the frequency and amplitude of each parameter. The data were analyzed with IBM SPSS Statistica 2.3 software using standard methods. Besides, non-linear statistics using ViDaExpert software with elastic map technique was utilized.

The elastic map perfectly separated the patients with PD and essential tremor, as well as healthy controls. Three clusters were observed. The analysis of composition of the clusters proved the better quality of olfactory function of the patients with essential tremor compared to the patients with PD. This bias confirms the hypothesis on the inverse dependence between the tremor level and olfactory dysfunction.