Breathing-related sleep disorder is characterized by a clinical complaint of excessive daytime sleepiness or insomnia or both. These symptoms result from periodic cessation of breathing (apnea), diminished amplitude of airflow (hypopnea), or increased work of breathing (upper airway resistance syndrome). These findings can be confirmed only during polysomnographic studies, although clinical history from the patient or bed partner may include breathing pauses or gasps. Other typical clinical symptoms include loud snoring and daytime sleepiness characterized by long, unrefreshing naps, as well as shorter episodes of inadvertent sleep.
Obstructive sleep apnea syndrome typically occurs in overweight, middle-aged men, who frequently have evidence of hypertension or cardiovascular disease. Reduced muscle tone during sleep and reduced airway patency due to obesity or craniofacial abnormalities lead to a collapse of the airway during inspiration. The cessation of breathing and resulting decreases in oxyhemoglobin saturation lead to arousal. This pattern may recur hundreds of times per night. Central sleep apnea syndrome, in which apneas occur with diminished central drive for respiration, occurs more commonly in individuals with congestive heart failure or central nervous system disorders, such as cerebrovascular disease. Although it clearly represents a physical condition, breathing-related sleep disorder is included as an Axis I condition in DSM-IV to facilitate the differential diagnosis of hypersomnia.
Behavioral/psychotherapeutic treatment Behavioral interventions for sleep apnea involve general avoidance measures, sleep position training, and weight loss. Most central nervous system depressant drugs aggravate sleep-related breathing disorders and increase oxyhemoglobin desaturation. Patients with sleep apnea should avoid sedative-hypnotics and alcohol 4-6 hours before bedtime (Guilleminault et al. 1984; Scrima et al. 1982).
Snoring and respiratory disturbances are typically worst when the patient sleeps in the supine position. Some patients, usually those of normal weight, may have sleep apnea that is strictly positional in nature. Interventions aimed at changing sleep posture should benefit these patients. A common home remedy is to sew a tennis ball into the back of a pajama to discourage the patient from sleeping on the back. Training to avoid the supine position can also be achieved with a gravity-sensitive position device that triggers an alarm whenever the patient is in the supine position. In one study, 10 patients with positional sleep apnea reduced their sleep apnea by about half after a single night of sleep position training, and 6 patients completely eliminated their apnea (Cartwright et al. 1985). A similar conditioning procedure was used to train patients with sleep apnea to resume breathing whenever there was a cessation of airflow for more than 5 seconds or a decrease in oxygen saturation below 90% (Badia et al. 1988). This procedure yielded a modest reduction in the duration, but not the frequency, of apneic events and a corresponding improvement in oxyhemoglobin saturation.
Obesity is an important risk factor for obstructive sleep apnea. Weight loss is almost always recommended for obese patients with sleep apnea. Surgical treatment may be needed for patients who are more than 100% over ideal body weight, whereas for others a multicomponent intervention combining very-low-calorie diets, exercise, and behavior change is the treatment of choice. Weight loss is effective in reducing the frequency of apneas and hypopneas and in improving sleep patterns (Harman et al. 1982; Smith et al. 1985; Suratt et al. 1992). Long-term benefits, however, are generally modest, and periodic follow-up evaluations with relapse prevention training are essential therapeutic components to maintain weight loss over time. Although weight loss is rarely sufficient to eliminate apneas, interventions targeting behavioral risk factors may help keep the apnea severity index just below a clinical threshold that would otherwise necessitate more invasive therapies.
Somatic treatment The mainstay of treatment in breathing-related sleep disorder is positive airway pressure delivered through a mask or nasal prongs. CPAP or BiPAP (with a higher level of pressure during inspiration) are both used to treat apnea (Strollo and Rogers 1996). The efficacy of CPAP in subjective and objective outcomes has been reported (Jenkinson et al. 1999). The level of pressure must be titrated individually in each patient to a level that suppresses apnea and hypopnea in all sleep stages and sleeping postures (Grunstein and Sullivan 2000). Available evidence suggests that titration in the laboratory is the most accurate and effective means of accomplishing this goal. CPAP is most clearly indicated in patients with the obstructive form of sleep apnea, but it is also helpful in many patients with mixed or central sleep apnea. Treatment should be initiated only after diagnostic sleep laboratory study. Oral appliances that maintain the patency of the airway can be a useful alternative to positive airway pressure in some patients, although overall efficacy appears to be less than that for CPAP (Clark et al. 1996; Ferguson et al. 1996). These devices work by displacing the tongue and/or jaw anteriorly, thereby increasing the posterior airway space and preventing airway obstruction.
Surgical therapy for breathing-related sleep disorder remains a viable option for patients with obstructive apnea and identifiable anatomic abnormalities or intolerance for CPAP. Obstruction may occur at different (or multiple) levels of the airway, including the nose, palate, and base of the tongue. Therefore, surgical interventions must be targeted, and staged interventions may even be necessary (Atwood et al. 1997).
Pharmacological treatment Pharmacological treatment has a very limited role in the treatment of breathing-related sleep disorder. Protriptyline and other TCAs and fluoxetine have been reported to improve oxyhemoglobin saturation, but the effect on actual apnea events is quite limited and of questionable clinical value (Brownell et al. 1982; Hanzel et al. 1991). Other medications, including theophylline, medroxyprogesterone, and acetazolamide, have also been used in patients with obstructive sleep apnea but with very limited results (Saletu et al. 1999; Sanders 1994).
Although medications do not effectively treat apnea per se, pharmacological management may provide symptomatic relief. Patients with breathing-related sleep disorder sometimes report disruption in the continuity of nocturnal sleep, which may impair their ability to use more definitive treatments. In such cases, a low dose of a sedating TCA may improve the continuity without worsening the breathing-related sleep disorder. Some patients have severe daytime sleepiness that is not relieved by somatic treatment alone. In such cases, judicious use of a low dose of stimulant medication may be instituted. Clinical trials with small numbers of subjects have demonstrated the utility of this approach (Arnulf et al. 1997; Guilleminault and Philip 1996).
Revision date: July 8, 2011
Last revised: by Tatiana Kuznetsova, D.M.D.