Restless Legs Syndrome (RLS) in patients with Parkinson’s disease (PD) is seen as a non-motor symptom with no well-defined pathophysiology. RLS development involves dopaminergic diencephalon spinal tract dysfunction and supraspinal brain structural changes.
Purpose: The study was to investigate the neurophysiological disorders in PD patients with RLS using methods of somatosensory evoked potentials (SEP), blink reflex (BR) and sympathetic skin response (SSR). Estimation of daily parameters was done in relation with twenty-four hours Holter monitoring (HM) and brain structural alterations identified by MRI studies using voxelbased morphometry.
Method: 36 PD patients with RLS and 39 PD patients without RLS (RLS-) from 40-70 years age group and 30 healthy individuals with similar age group were examined twice a day at 8 am and 6 pm.
Result: In PD patients with RLS observed a significant increase in the amplitudes N20-P23, N13-P18, and N9-P8. Besides in the non-RLS group, the inter-peak interval (IPI) N9-N13, N11-N13 was shorter and the IPI N13-N20 was longer. PD patients with RLS have the predominance of sympathetic influence on the SSR. Thus a decrease in latency and an increase in the amplitude of second BR components are observed that indicate excessive polysynaptic reflex excitability at the brainstem level. HM detected the decrease in the circadian index that was a general trend of all the patients with PD, but a specific change in the time-domain parameters of heart rate variability also suggests autonomic dysfunction in the form of reduced sympathetic activity in PD patients with RLS. Disturbance of somatosensory processes and autonomic regulation have daily variability, which reflects the circadian pattern of RLS in PD. Structural changes in certain brain structures probably associate with functional neurophysiological abnormalities identified by mean voxel-based analysis of MTR images can be considered as predictors of RLS in PD patients.

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