Restless legs syndrome: impact on sleep-related breathing disorders.

Restless legs syndrome (RLS) is a common chronic sensory-motor neurological disorder that remains a clinical diagnosis. Most RLS patients present with sleep complaints in the form of initiation and/or maintenance insomnia as RLS has a circadian rhythmicity. An increased number of periodic leg movements during sleep (PLMS) is a supportive criterion in the diagnosis of RLS. Abnormalities in the central dopaminergic and iron systems are involved in the physiopathology of RLS. There is a higher prevalence of RLS and PLMS in sleep-disordered breathing patients, particularly those with obstructive sleep apnoea (OSA), the most common sleep disorder in western societies. The complex mechanisms underlying the association between OSA, RLS and PLMS remain unclear. Untreated OSA can lead to adverse cardiovascular consequences due to cardio-metabolic dysfunction. It remains controversial whether RLS could further adversely impact the cardiovascular consequences of OSA. The PLMS do not have an additive effect on the hypersomnia experienced by some sleep-disordered breathing patients. Continuous positive airway pressure (CPAP) therapy is the most effective therapy for OSA. The presence of PLMS during CPAP treatment could be a marker of an incomplete resolution of sleep-disordered breathing in the form of increased upper airway resistance syndrome, despite treatment. Dopaminergic agonists are the preferred agent for the treatment of RLS, and are indicated when RLS symptoms are frequent and affect quality of life. PLMS and RLS do not seem to contribute to the residual hypersomnia that can be observed in some sleep-disordered breathing patients despite adequate compliance and effective CPAP therapy.

Medication effects on sleep.

The understanding of the neuropharmacologic reciprocal interactions between the sleep and wake cycles has progressed significantly in the past decade. It was also recently appreciated that sleep disruption or deprivation can have adverse metabolic consequences. Multiple medications have a direct or indirect impact on sleep and the waking state. This article reviews how commonly prescribed medications can significantly affect the sleep-wake cycle.

Continuous positive airway pressure: new generations.

Automatic positive airway pressure devices are the most technologically advanced positive airway pressure devices available for use in OSA. Although heterogeneous, they have in common the ability to detect and respond to changes in upper airway resistance. Data cannot necessarily be extrapolated from one device to another, and the field is rapidly advancing. Most studies of APAP have been performed in a supervised setting, or patients have been carefully selected to have a high likelihood of OSA uncomplicated by disorders such as alveolar hypoventilation or central apnea or technical problems such as mask leaks. Studies of APAP for the diagnosis of OSA have shown that APAP can diagnose severe OSA effectively, but the diagnosis of mild-moderate OSA is less reliable. APAP devices also can be effective therapy for selected patients with OSA, with overall similar results to conventional fixed CPAP in terms of respiratory disturbances, sleep quality, nocturnal oxygenation, and daytime sleepiness and performance, with less known or other long-term outcomes. In most studies, mean treatment pressures are lower, without change in side effect profile. Compliance and preference with APAP are similar to or somewhat better than CPAP in most studies. APAP also can be used in an attended setting to titrate an effective pressure for use in long-term conventional CPAP therapy, also with similar results to CPAP in many patients. APAP devices are more expensive than CPAP devices, but the cost may be outweighed if a group of patients who can be diagnosed, treated, or titrated safely in the unattended setting can be identified. Although diagnostic and therapeutic algorithms for APAP have been proposed, the best candidates for this modality must be defined better.