High Prevalence of Orthostatic Dysregulation among Circadian Rhythm Disorder Patients.

STUDY OBJECTIVES: Patients with circadian rhythm sleep disorders (CRSDs) often have coincidence of orthostatic dysregulation (OD). Both disorders have many common clinical features. However, the prevalence of OD in patients with CRSD has not been examined. METHODS: Thirty-eight patients with CRSD with either delayed sleep phase disorder or free-running disorder were tested for OD using the new orthostatic test, which was originally established by Tanaka et al. (< 20 years) and the Schellong test, i.e., the active standing test (≥ 20 years). RESULTS: The overall prevalence of OD in patients with CRSD was 57.9% (22/38), and prevalence of OD was 70% in patients under 20 years of age (14/20). These rates exceed the previously reported values in adolescents aged 14-15 years (15%), regarded as the age with highest OD prevalence. Prevalence was not significantly associated with CRSD severity and medications used. CONCLUSIONS: We observed a high prevalence of OD in patients with CRSD, suggesting some relationship between CRSD and OD. Large-scale case-control studies are warranted to investigate the underlying mechanisms for this comorbidity.

[Primary insomnia].

Primary insomnia is relatively common. According to The International Classification of Sleep Disorders, primary insomnia is a syndrome mainly composed of psychophysiological insomnia, paradoxical insomnia and idiopathic insomnia. Primary insomnia is difficulty initiating sleep (sleep onset insomnia), difficulty maintaining sleep (mid-sleep awakening, early morning awakening) or chronic non restorative sleep, which persist longer than three weeks despite having adequate opportunity for sleep and result in impaired daytime functioning. Primary insomnia is not explained by currently known psychiatric disorders, medical conditions, substance use disorders. Primary insomnia is a non-organic, unknown etiology, middle-aged female predominant sleep disturbance. Recent findings suggest the hyperarousal hypothesis of primary insomnia. In the near future, non restorative sleep might be excluded from the definition of primary insomnia.

Rapid eye movement-localized apnea in a female patient with chronic insomnia.

A middle-aged female patient with chronic insomnia showed rapid eye movement (REM)- localized obstructive sleep apnea. She visited the Sleep Disorders Clinic and complained of insomnia with loud snoring. Once, in the past, her sleep complaints had disappeared after weight reduction but, 6 months later, she complained of excessive daytime sleepiness. Overnight polysomnography revealed REM-localized apnea. Careful follow up is strongly recommended for a female patient with chronic insomnia who shows REM-localized apnea.