EEG mapping, psychometric, and polysomnographic studies in restless legs syndrome (RLS) and periodic limb movement disorder (PLMD) patients as compared with normal controls.

OBJECTIVES: Investigation of daytime brain function, psychopathology, and objective and subjective sleep and awakening quality in restless legs syndrome (RLS) and periodic limb movement disorder (PLMD). METHODS: Thirty-three RLS and 26 PLMD patients free of psychotropic drugs were studied as compared with age- and sex-matched normal controls, utilizing electroencephalographic (EEG) mapping and clinical evaluations by the Zung Self-Rating Depression (SDS) and Anxiety Scale (SAS), the Quality of Life Index, the Pittsburgh Sleep Quality Index (PSQI), and the Epworth Sleepiness Scale. In a subsample of 12 RLS patients, 12 PLMD patients, and 12 controls, objective and subjective sleep and awakening quality were evaluated in two sleep laboratory nights (adaptation and baseline night). RESULTS: Scores of the PSQI, SDS, and SAS were found increased in both patient groups; RLS patients showed reduced quality of life, while in the PLMD group daytime sleepiness was increased. EEG mapping demonstrated findings characteristic of major depression in RLS patients and of generalized anxiety disorder in PLMD patients. Polysomnography showed a significant deterioration of sleep efficiency only for RLS patients, while nocturnal awakenings were increased in both patient groups. Concerning sleep architecture, both groups exhibited increased S1 and stage shifts and decreased S2, while only PLMD patients showed an increase in S4. The PLM/(h TST), the PLM/(h wake) and the PLMS-arousal index were significantly increased in both patient groups as compared with controls. Subjective sleep and awakening quality and thymopsychic measures were deteriorated in RLS. Morning mental performance and fine motor activity were deteriorated in both groups, reaction time only in RLS, numerical memory and attention variability only in PLMD. CONCLUSION: EEG mapping revealed neurophysiological correlates of depression and anxiety in RLS and PLMD, respectively, which were confirmed by self-ratings of symptoms.