Abnormality of N30 somatosensory evoked potentials in Parkinson’s disease: a multidisciplinary approach

Purpose of the study – Assess the N30 component of median nerve somatosensory evoked potentials (SEPs) in patients with Parkinson’s disease (PD) and correlate its parameters with the severity of the disease, general cognitive ability and regional cerebral blood flow (rCBF). Patients and methods – Twenty-three non-demented, non-depressed PD patients (at stage II and III of the disease) and 23 age- and education-matched normal controls were enrolled in the study. SEPs were elicited by median nerve stimulation. PD patients’ cognitive ability was assessed by means of: 1) Raven’s Colored Progressive Matrices (RCPM); 2) the Test of Non-Verbal Intelligence (TONI-2); and 3) the Wisconsin Card Sorting Test (WCST). The patients’ rCBF was evaluated by HMPAO SPECT. Results – There was no difference between SEP N30 latency in PD patients and controls ( P > 0.05). The P20-N30 peak-to-peak amplitude was lower in PD patients bilaterally ( P < 0.05), and the amplitude of N30-P40 was lower on the right side only ( P