Periodic Limb Movements Are Associated with Vasomotor Symptoms

Abstract

diagnosis of periodic limb movement disorder (PLMD) is established when the affected individual also has insomnia and/or excessive daytime drowsiness. By subjective reports, the prevalence of PLMD has been estimated to be 3.9% in the general population. Restless legs syndrome (RLS) is a common sensory-motor disorder that produces uncomfortable sensations and a constant urge to move the lower limbs, and has a typical diurnal pattern with a peak of symptoms during rest periods in the evening and at night. RLS has also been reported to be associated with cardiovascular disease (CVD). 8 In contrast to PLMs, the diagnosis of RLS is based on the patient's subjective symptoms. PLMs are related to RLS, and the majority of patients with RLS display PLMs during sleep. 9 Prior studies have discussed the S C I E N T I F I C I N V E S T I G A T I O N SP eriodic limb movements (PLMs) during sleep were fi rst described in 1953 as "nocturnal myoclonus," and were at that time thought to have similarities to nocturnal epilepsy. 1The pathophysiological mechanisms of PLMs are unclear, but abnormal hyperexcitability (or diminished inhibition) in the lumbosacral and cervical segments of the spinal cord have been hypothesized to be possible causes.2 PLMs are characterized by involuntary movements of the lower extremities, specifi cally the toes, ankle, knees, and hips, typically lasting between 0.5 and 10 seconds. The patient is usually unaware of the limb movements or the frequent sleep disruptions, and PLMs are often an incidental fi nding at polysomnography (PSG).3 PLMs may cause microarousals, leaving the affected patient fatigued the following day. Previously, it was assumed that PLMs were the cause of these arousals, but more recent studies have revealed that PLMs and arousals are associated in a more complex and non-unidirectional manner. Arousals can occur before, during, and after leg movements, indicating that the phenomenon is associated with an underlying arousal disorder. 4 The exact prevalence of PLMs is unknown. They appear to be rare in children, to progress with advancing age, and to be more common in females than in males. 5,6 In studies where PLMs have been objectively documented (PLM episodes/h of sleep > 5), the prevalence was 5% to 6% in younger adults, and 25% to 58% among elderly people. BRIEF SUMMARYCurrent Knowledge/Study Rationale: Sleep disturbances affect a substantial fraction of women during the menopausal transition, and female sex hormones are possibly involved in the origin of PLMs. It is currently unknown whether PLMs are associated with the menopausal transition and/or concomitant vasomotor symptoms. Study Impact: This study shows an association between symptoms related to declining levels of estrogen, i.e. vasomotor symptoms, and PLMs. Future studies should address the possibility of using hormone replacement therapy in postmenopausal women with PLMD.

Why Are Women Prone to Restless Legs Syndrome?

“…If high levels of estrogen triggered RLS, one would expect the rate or severity to diminish after menopause but this does not happen, nor does the use of hormone replacement therapy lead to an increased incidence [38]. Periodic limb movements, in fact, increase at menopause and are associated with vasomotor symptoms [39].…”

Limb movements during sleep in children: effects of age, sex, and iron status in more than 1,000 patients referred to a pediatric sleep center

“…Another possibility is that hormonal changes associated with puberty could contribute to differences in LMs; supporting this notion are studies demonstrating increased PLMS and/or RLS with hormonal changes associated with menopausal transition or pregnancy. 20,21 Another possibility is that it could be due to medication effect because adolescents are at increased risk of the development of mood disorders and therefore could be placed on psychotropic medications which can increase PLMS; in the current study we did not have medication data readily available to examine this hypothesis. Surprisingly, and of great clinical interest, we found minimal to no relationship between LMs and ferritin levels.…”

Italian Association of Sleep Medicine (AIMS) position statement and guideline on the treatment of menopausal sleep disorders

“…A Swedish study reported increased prevalence of RLS among women with VMS during the menopause transition, but not in MHT users [60]. In a subsequent study [61], the same authors noted an association between women with VMS and clinically significant periodic limb movements (PLMs)/RLS, but not PLMs with arousal. The mechanisms underlying the association are unclear.…”