To search for additional methods of differential diagnosis ofessential tremor (ET) and early-stage Parkinsons disease(PD), a clinical, psychometric, tremorometric, stabilometricand electrooculografic study was carried out in PD, ET andage-matched controls. Patients with ET had bilateral distributionof predominantly postural-kinetic tremor with slightprevalence in one hand, and limb tremor often combined withhead tremor. PD was characterized by asymmetric debut ofclinical manifestations, as well as by rest and postural tremorwith slight hypokinesia and rigidity. The frequency of rest andpostural tremor was significantly higher than in the PD group.Stabilometry revealed improvement of postural stability inTarget-test in patients with PD. In the dynamic Evolventatestpatients with PD showed smaller statokinetic curve lengthand lower center-of-motion velocity compared to healthy subjects.No stabilometric changes were found in ET patients. Incontrast to ET, patients with PD were characterized by significantincrease in latencies of saccadic eye movements and fractionof multi-step saccades; eye movements lateralization wasrevealed on stage I of PD. Discussed is significance of theobtained data for clinical practice.

We registered visually-guided and self-paced saccadic eye movements in patients with Parkinson’s disease and healthy humans of different ages. We suppose that oculomotor abnormalities in Parkinson’s disease are due to two processes: pathological neurodegeneration and normal aging.

The age-related changes in saccadic eye movements (the latency, the duration of single saccades and the percentage of multistep saccades) were compared in healthy subjects and patients with Parkinson’s disease. Healthy volunteers without neurological symptoms were divided into six age groups: (17–20, 21–30, 31–40, 41–50, 51–60, and 61–75 years of age); and parkinsonian patients, into three groups (41–50, 51–60, and 61–75 years of age). According to the data obtained, the saccade characteristics depend on the age in both the subjects without neurological symptoms and parkinsonian patients. In healthy volunteers, the percentage of multistep saccades and the mean saccade latency increase significantly after the age of 60 years. These parameters in patients with Parkinson’s disease significantly exceed the values in healthy subjects from the age-matched groups. The “disease” factor has a greater influence on the saccade latency and the percentage of multistep saccades than the “age” factor. The duration of single saccades depends on age to a lesser degree and does not change in patients with Parkinson’s disease. The peculiarities of the development of neurodegenerative processes in cases of normal aging and in idiopathic parkinsonism are discussed.

Parameters of saccadic eye movements were studied in patients with degenerative extrapyramidal syndromes and in control subjects. The effects of age-related and pathological neurodegeneration are discussed.