Neurophysiological and neuropsychological assessment of cognitive function in patients with restless legs syndrome

Restless legs syndrome (RLS) is a sensorymotor neurological disorder shown a negative impact on sleep and quality of life. Recent studies also claim that cognitive dysfunction is accompanied with RLS. The purpose of this study is to evaluate cognitive functions detected by neuropsychological and neurophysiological tests of patients with RLS. Fifteen patients with RLS fulfilled the diagnostic criteria proposed by the International RLS Study Group were enrolled into the study. Fifteen healthy voluntary with similar demographic characteristics were also enrolled into the study as a control group. Seven cognitive tests were used: Mini Mental State Examination, Verbal Fluency Tests (letter and category), Trail Making Test (A and B), Judgement of Line Orientation Test, Digit Span Test, Wisconsin Card Sorting Test and Coloured Progressive Matrices Test. The event related potentials (ERPs) including P300 and Mismatch Negativity were recorded using auditory oddball paradigm. There were no statistically significant difference between the cognitive test scores and ERPs results of the RLS patients and control groups. Consequently this is the first study evaluating cognitive functions in patients with RLS by using neuropsychological and neurophysiological tests at the same time. We cannot find any evidence suggesting cognitive dysfunction in RLS patients group