FRIDAY, Sept. 1 (HealthDay News) -- Researchers have identified a new sleep disorder, called complex sleep apnea syndrome, which is similar to obstructive sleep apnea hypopnea syndrome but the symptoms are not relieved by treatment with continuous positive airway pressure, according to a study in the September issue of Sleep.
Timothy I. Morgenthaler, M.D., from the Mayo Clinic Sleep Disorders Center in Rochester, Minn., and colleagues examined the clinical characteristics of 223 consecutive patients referred to a sleep disorders clinic plus 20 patients diagnosed with central sleep apnea syndrome.
The research team found that in the referred group, the prevalence of complex sleep apnea syndrome was 15 percent, obstructive sleep apnea hypopnea syndrome was 84 percent, and central sleep apnea syndrome was 0.4 percent. Patients with complex sleep apnea syndrome were more likely to be male compared with those with obstructive sleep apnea hypopnea syndrome and had significantly fewer maintenance insomnia complaints than those with central sleep apnea syndrome, but otherwise had no distinguishing clinical features. Although continuous airway pressure suppressed obstructive breathing, the number of apneas plus hypopneas per hour of sleep remained high for those with complex sleep apnea syndrome and central sleep apnea syndrome.
"Complex sleep apnea syndrome patients are mostly similar to those with obstructive sleep apnea hypopnea syndrome until one applies continuous positive airway pressure," Morgenthaler and colleagues conclude. "Clinical risk factors don't predict the emergence of complex sleep apnea syndrome, and best treatment is not known."