Neurophysiological Characteristics Of Restless Legs Syndrome In Parkinson’s Disease
Aim of the study: To investigate the neurophysiological features of restless legs syndrome (RLS) in Parkinson’s disease (PD).
Methods: We used International RLS Severity Scale and investigated somatosensory evoked potentials (SEPs), blink reflex (BR) and sympathetic skin response (SSR). 75 patients with PD were examined at the age of 40-70 years: 36 with RLS (RSL+) and 39 – without RLS (RLS-). 30 healthy individuals were included in the control group.
Results: SEPs study revealed that in the RLS+, the inter-peak intervals (IPI) N9–N13, N11–N13 were significantly shorter and the IPI N13-N20 was longer as compared with the RLS- group. A significant increase in the amplitudes N20-P23 and N13-P18 was observed in the RLS+, which reflects sensitization processes in patients with RLS. A trend to hyperexcitability responses of BR was observed, which can reflect insufficiency of the inhibitory mechanisms at the segmental level and deficiency of supraspinal descending control in PD patients with RLS. SSR study revealed prolonged latency and an increase in the amplitude in the RLS+ group and positive correlation between the severity of RLS (according to International RLS Severity Scale) and SSR latency.
Conclusion: A change in the complex interaction between the peripheral, spinal and cerebral divisions of the nervous system was revealed in RLS. Identified somatosensory disturbances and changes in the brainstem and spinal reflexes probably determine the clinical features of RLS in PD.