Periodic Leg Movements in Sleep and Restless Legs Syndrome Relation to Daytime Alertness and Sleepiness

It has been assumed that periodic leg movements in sleep and the frequent arousals associated with them cause clinically significant insomnia and daytime sleepiness, but studies do not support this relationship. Restless legs syndrome (RLS) is associated with decreased sleep efficiency and short sleep times. RLS studies have consistently failed to find presence of the daytime sleepiness expected for the short sleep time. Some of the other effects of chronic sleep deprivation have been shown clinically and one recent report documented the expected cognitive impairment of frontal lobe function. RLS patients seem to have some altered arousal increasing alertness and overcoming sleepiness despite profound sleep loss.