Leg movements and periodic leg movements during sleep in the development across childhood and adolescence from 1 to 18 years.

Objective: Age specific reference values of leg movements (LMS) and periodic leg movements (PLMS) in sleep considering their true periodicity to evaluate sleep pathologies, especially possible childhood RLS or PLMD.

Methods: In a prospective first night study of 52 healthy children/adolescents divided into six age groups from 1 to 18 years, polysomnographies were conducted and scored considering AASM rules. The frequency of LMS and PLMS were evaluated for NREM, REM, total sleep time (TST), including attention to time structure (inter-leg movement intervals, time distribution during the night) and periodicity of LMS.

Results: LMS and PLMS decreased with increasing age (P < 0.05). Children and adolescents older than 10 years had a PLMS index less than 5/h TST, in younger children the PLMS index was higher; 34.7% of total LMS and PLMS were accompanied by an EEG-arousal without age dependence. Periodicity index was low (median 0.2 decreasing with age to 0.1). Inter-leg movement intervals showed a decreasing incidence of shorter intervals with age. The course of LMS during the night displayed a lack of clear structure of distribution.

Conclusions: To evaluate pediatric motoric sleep disturbances it is necessary to consider the age dependence of LMS/PLMS and their true periodicity.