What is the clinical significance of periodic limb movements during sleep?

Periodic Leg Movements During Sleep

Periodic leg movements during sleep (PLMS) are a frequent finding in nocturnal sleep registrations that include tibialis anterior electromyographic signals. Different PLMS scoring rules exist and can have a major impact on PLMS frequency, which tends to be underappreciated. There is no consistent evidence that frequent PLMS are a causal risk factor for clinically significant outcomes. Several critical open questions are identified that need to be addressed, including but not limited to the consideration of the full range of all sleep-related leg movement activity.

Factors associated with fatigue in patients with insomnia

Although fatigue is common in insomnia, the clinical associates of fatigue in patients with insomnia are largely unknown. We aimed to investigate the clinical associates of fatigue in patients with insomnia. Patients visiting the Stanford Sleep Medicine Center completed the Insomnia Severity Index (ISI), Insomnia Symptom Questionnaire (ISQ), the Fatigue Severity Scale (FSS), the Epworth Sleepiness Scale (ESS), and the Patient Health Questionnaire (PHQ-9). Among 6367 patients, 2024 were diagnosed with insomnia (age 43.06 ± 15.19 years; 1110 women and 914 men) according to the ISI and the ISQ. Insomnia patients with severe fatigue (n = 1306) showed higher insomnia symptoms, daytime sleepiness, depression and longer habitual sleep duration than those without severe fatigue (n = 718). Higher insomnia symptoms, daytime sleepiness and depressive symptoms, and longer habitual sleep duration, independently predicted higher fatigue scores. Among insomnia patients with daytime sleepiness (ESS≥10), only habitual sleep duration and depression predicted fatigue scores. The interaction between insomnia severity and daytime sleepiness significantly predicted the severity of fatigue. Depression was a significant mediator between insomnia and fatigue. For 598 insomnia patients undergoing overnight polysomnography (PSG), no significant correlations were found between fatigue and any PSG parameters. The current study suggests that managing insomnia or depression may reduce the fatigue of insomnia patients, whereas arbitrary efforts to prolong sleep duration may worsen their fatigue.

Residual excessive sleepiness in patients with obstructive sleep apnea on treatment with continuous positive airway pressure

PURPOSE OF REVIEW

One of the most common causes of excessive daytime sleepiness in clinical practice is obstructive sleep apnea syndrome (OSAS). So far, continuous positive airway pressure (CPAP) is the most effective treatment for OSA. Some of the patients do not improve on CPAP and remain sleepy despite using CPAP.This review provides updated information about the possible causes of residual sleepiness whilst using the CPAP in patients with OSAS.

RECENT FINDINGS

Prevalence of OSAS has increased recently to 23.4% in women and 49.7% in men. Periodic limb movement, behaviorally induced insufficient sleep syndrome and depression are the most common causes of persistent sleepiness on CPAP. Residual sleepiness after exclusion of all possible causes is 6%.

SUMMARY

There is still lack of sufficient evidence about the accurate characteristics and possible causes of this residual sleepiness and how to address this in large prospective studies.

Topiramate-induced periodic limb movement disorder in a patient affected by focal epilepsy

Periodic limb movement disorder (PLMD) is characterized by pathological periodic limb movements during sleep, insomnia and/or diurnal sleepiness, and the absence of another primary sleep disorder. We report a patient with complex partial seizures who developed PLMD while taking topiramate (TPM). He had no evidence of metabolic and/or other conditions inducing PLMD. He also had fragmented sleep and disruptive PLMS on polysomnography, and PLMS subsided with change of antiepileptic drug. Topiramate may modulate the dopaminergic pathway by inhibition of glutamate release, thereby inducing PLMD as observed in our patient. Although a single case does not allow any generalization, PLMD should be considered in patients complaining of insomnia and treated with TPM.

Periodic limb movements during sleep and their effect on the cardiovascular system: is there a final answer?

Periodic limb movements during sleep (PLMS) is a sleep-related movement disorder characterized by repetitive limb movements during sleep, seen predominantly in the legs but also occasionally involving the arms. These movements may be associated with arousals that can lead to increases in sympathetic tone, resulting in tachycardia and elevated systolic blood pressure. Chronic sustained tachycardia and elevated systolic blood pressure are known to be associated with the development of arrhythmias, hypertension, left ventricular hypertrophy, and congestive heart failure. However, the data are not entirely clear on whether untreated PLMS is associated with these cardiovascular risks. This review examines the current evidence on whether PLMS has any effect on the cardiovascular system.

Clinical pharmacology in sleep medicine

The basic treatment goals of pharmacological therapies in sleep medicine are to improve waking function by either improving sleep or by increasing energy during wakefulness. Stimulants to improve waking function include amphetamine derivatives, modafinil, and caffeine. Sleep aids encompass several classes, from benzodiazepine hypnotics to over-the-counter antihistamines. Other medications used in sleep medicine include those initially used in other disorders, such as epilepsy, Parkinson's disease, and psychiatric disorders. As these medications are prescribed or encountered by providers in diverse fields of medicine, it is important to recognize the distribution of adverse effects, drug interaction profiles, metabolism, and cytochrome substrate activity. In this paper, we review the pharmacological armamentarium in the field of sleep medicine to provide a framework for risk-benefit considerations in clinical practice.