The role of microsleeps to estimate sleepiness at the wheel and near-miss accidents in obstructive sleep apnea.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is considered a risk factor for sleepiness at the wheel (SW) and near-miss accidents (NMA). To date, there are subjective and objective methods such as the Maintenance of Wakefulness Test (MWT) to investigate sleepiness. However, these methods have limitations. Therefore, a new analysis of the MWT was introduced based on the identification of microsleeps (MS). So, we tested MS analysis to improve the discriminative ability of MWT in recognizing individuals at risk for SW and NMA in a population with OSA. METHODS: The study was conducted on 100 naïve patients with suspected OSA referred to our Sleep Medicine Unit. All patients performed a full-standard polysomnography and MWT. The MWT was analyzed according to standard criteria, and the presence of MS episodes, the mean MS latency and the MS density (the mean absolute or relative number of MS) were assessed. RESULTS: Microsleeps were observed in 100% of alert or sleepy patients and 47% of the fully alert (P <0.0001). Almost 90% of patients reporting NMA showed episodes of MS during MWT. The occurrence of NMA was related to EDS, MS latency and MS density (P <0.001). The discriminative power for the NMA of MS density measures was higher than that derived from latency analysis, particularly in patients without EDS and with a simultaneous mean sleep latency >33 minutes. CONCLUSIONS: MS analysis provides objective evidence of sleepiness and, therefore, could improve the discriminative ability of the MWT in recognizing individuals at high risk for accidents.

Evening melatonin timing secretion in real life conditions in patients with Alzheimer disease of mild to moderate severity.

BACKGROUND: Circadian dysfunction is thought to take part in the pathogenesis of sleep disorders in Alzheimer's disease (AD) and in AD pathophysiology itself. OBJECTIVE: Our study aims to calculate dim light melatonin onset (DLMO) secretion in order to define the circadian phase in patients with AD at an early stage of the disease. METHODS: Twenty-one patients (M/F: 11/10; mean age 74.1 ± 5.4 years; mean disease duration 3.4 ± 1.6 years) with a diagnosis of AD and 17 healthy controls (HC; M/F: 10/7; mean age 67.47 ± 3.8 years) were investigated for subjective nocturnal sleep quality and chronotype, for DLMO and quantitative aspects of the evening melatonin secretion by means of a 5-point in-home evening melatonin saliva test. RESULTS: Subjective sleep quality score on the Pittsburgh Sleep Quality Index questionnaire (PSQI) above 5 (p = 0.24), insomnia frequency as measured by Sleep Condition Indicator Questionnaire (p = 0.823) and the subjective chronotype according to Morning Evening Questionnaire (MEQ) scores distribution (p = 0.464) did not differ between AD and HC. However, DLMO occurred significantly later (55 min; p = 0.028), and melatonin secretion following DLMO was significantly decreased in AD patients compared to HC. CONCLUSION: Initial evening secretion of melatonin proves to be delayed and mildly impaired in patients with a mild/moderate form of Alzheimer disease while patients' subjective sleep parameters and chronotype are reported to be similar to those of HC. These results indicate that subclinical altered patterns of melatonin secretion occur in subjects with AD at an early stage of the disease.