Microsleep as a marker of sleepiness in obstructive sleep apnea patients.

We hypothesized that: (a) the presence of microsleep (MS) during a Maintenance Wakefulness Test (MWT) trial may represent a reliable marker of sleepiness in obstructive sleep apnea (OSA) patients; (b) the number of MSs will be higher in sleepy versus non-sleepy patients with a borderline MWT mean sleep latency; and (c) scoring MS during MWT analysis may help physicians to recognize patients with a higher degree of sleepiness. We analysed the MWT data of 112 treatment-naïve OSA patients: 20 with short sleep latency (SL, sleep latency <12.8 min), 43 with borderline latency (BL, sleep latency between 12.8 and 32.6 min) and 49 with normal latency (NL, sleep latency >32.6 min). Microsleep was identified in all SL, in 42 BL and in 18 NL patients, with a median latency of 5.6 min. Accordingly, patients were classified into two subgroups: group A (n = 43) with microsleep latency <5.6 min and group B (n = 69) with microsleep latency >5.6 min when present. The mean sleep latency in the MWT was 14.5 ± 7.5 min in group A and 34.6 ± 7.4 min in group B (p < 0.0001). The number of microsleep episodes during each MWT trial was higher in group A than in group B. Sleep latency survival curves demonstrated different patterns of sleep latency in these groups (log-rank test <0.0001). This finding was confirmed in a Cox proportional hazard analysis: the presence of a mean MS latency <5.6 min is associated with an increasing risk of falling asleep during the MWT (RR, 1.93; 95 CI 1.04-3.6; p = 0.03). We conclude that the detection of microsleep may help in discriminating OSA patients with and without daytime vigilance impairment.

Activation of the motor cortex during phasic rapid eye movement sleep.

When dreaming during rapid eye movement (REM) sleep, we can perform complex motor behaviors while remaining motionless. How the motor cortex behaves during this state remains unknown. Here, using intracerebral electrodes sampling the human motor cortex in pharmacoresistant epileptic patients, we report a pattern of electroencephalographic activation during REM sleep similar to that observed during the performance of a voluntary movement during wakefulness. This pattern is present during phasic REM sleep but not during tonic REM sleep, the latter resembling relaxed wakefulness. This finding may help clarify certain phenomenological aspects observed in REM sleep behavior disorder.

Validation Study of Airgo, an Innovative Device to Screen Sleep Respiratory Disorders.

Background: Obstructive sleep apnea affects a consistent percentage of the population, and only a minority of patients have been diagnosed and treated because of a discrepancy between resources available for diagnosis and the epidemiology of a disorder possibly affecting nearly one billion people in the world. Aim: We conducted a study to compare a standard home respiratory monitoring system (Nox T3) with a novel device (Airgo™) consisting of an elastic band and a small recorder, light, comfortable for the patient, and low-cost complete with automatic analysis of the data that produces a screening report indicating the type and severity of sleep respiratory disorder. Patients and Results: We examined 120 patients, reduced to 118 for technical problems. The mean (SD) age of the patients is 55.7 ± 13 years, their BMI is 27.8 ± 4.3 kg/m2, and their AHI is 22 ± 22 events/h. Patients belong to all the different severity rates of OSA, with a percentage of them classified as free of respiratory disorders. The Airgo™ showed excellent agreement with the results of the gold standard, reporting high levels of sensitivity, specificity, positive and negative predicted value, and accuracy. Conclusion: Airgo™ is a reliable tool to screen patients with suspected sleep respiratory disorders, well tolerated by the patient based on totally automatic analysis and reporting system, leading to more efficient use of doctor's and clinician's time and resources and extending the opportunity to diagnose more possible candidates for treatment.

Anxiety and depressive symptoms on continuous positive airway pressure: long-term adherence in patients with sleep apnea syndrome.

BACKGROUND: Obstructive sleep apnea (OSA) is often associated to mood disorders and anxiety symptoms that may influence negatively the treatment approach. However, the relationship between anxiety, depression and adherence to treatment is still unclear. We investigate the presence of anxiety and depressive symptoms in newly diagnosed OSA patients and the link between psychological symptoms and acceptance or adherence to CPAP after one year. METHODS: A validated Italian questionnaire for anxiety and depressive symptoms was administered to 249 patients (69F) with a mean age of 57.2±12.2 and a mean AHI of 40.9±21.9 (ev*hr-1). The CPAP use in the first and last night of acclimatization and one year after prescription was 6.4±2.2, 6.9±1.4 and 5.3±2.2 hr, respectively. RESULTS: Anxiety symptoms were reported by 15.6% of patients, depressive symptoms by 6% while 12.5% reported both anxiety and depressive symptoms. Adherence to CPAP in the first night was not adequate in 19.7% of patients with relevant difference between groups: 16.4% in AD-,20.5% in A+,13.3% in D+ and 38.7% in AD+ (χ2=8.6; P=0.03). However, at the end of acclimatization period only 4.4% of patients utilized CPAP<5/h. One-year after prescription the adherence was adequate in 74.7% of patients without difference between groups. A Cox proportional hazard model demonstrated that AHI (OR=0.985, 95% CI: 0.97-0.99; P=0.03) and compliance to CPAP at the first night of use (OR=0.445; 95% CI: 0.246-0.8; P=0.007) are the only predictive factors of long-term compliance. CONCLUSIONS: Presence of anxiety and depressive symptoms should be checked before PAP titration since they may negatively influence the early acclimatization and adherence.

Determinants of Sleepiness at Wheel and Missing Accidents in Patients With Obstructive Sleep Apnea.

STUDY OBJECTIVES: Motor-vehicle crashes are frequent in untreated OSA patients but there is still uncertainty on prevalence as well as physiological or clinical determinants of sleepiness at the wheel (SW) in OSA patients. We assessed determinants of SW or sleepiness related near-miss car accident (NMA) in a group of non-professional drivers with OSA. METHODS: A 237 consecutive, treatment-naïve PSG-diagnosed OSA patients (161 males, 53.1 ± 12.6 years) were enrolled. Self-reported SW was assessed by positive answer to the question, "Have you had episodes of falling asleep while driving or episodes of drowsiness at wheel that could interfere with your driving skill in the last year?" Occurrence of NMA in the last 3 years was also individually recorded. Habitual self-reported average sleep time was collected. RESULTS: SW was found in 41.3% of patients but one-quarter of patients with SW did not report excessive daytime sleepiness. Predictors of SW were the following subjective factors: Epworth sleepiness scale score (ESS-OR 1.26; IC 1.1-1.4; p < 0.0001), depressive symptoms (BDI-OR 1.2; IC 1.06-1.18; p < 0.0001) and level of risk exposure (annual mileage-OR 1.9; IC 1.15-3.1; p = 0.007). NMAs were reported by 9.7% of patients, but more frequently by SW+ than SW- (22.4% vs. 0.7%; χ2 31, p < 0.0001). The occurrence of NMAs was significantly associated to ESS, BDI, habitual sleep duration and ODI (R 2 = 0.41). CONCLUSION: SW is not predicted by severity of OSA. Evaluation of risk exposure, assessment of depressive symptoms, and reported NMA should be included in the clinical evaluation, particularly in patients with reduced habitual sleep time and severe nocturnal hypoxia.

Development and validation of the Maugeri Sleep Quality and Distress Inventory (MaSQuDI-17).

OBJECTIVES: The aim of this study was to develop and validate a questionnaire designed to measure the impact of sleep impairment on emotional distress in patients with various sleep disorders. METHODS: Five experts created an item data-bank pertaining to sleep-related psychological symptoms and somatic perceptions. Fifty patients in two focus groups examined each item for: a) word clarity (indicating any ambiguity of interpretation) and b) appropriateness for the target population. This process permitted to identify 36 appropriate items. Classical Test Theory and Rasch Analysis were used to further refine the questionnaire, yielding the final 17-item set. Concurrent validation of the new scale was tested with the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and the Anxiety and Depression questionnaires. RESULTS: Starting from the initial item data-bank, a 17-item questionnaire, the Maugeri Sleep Quality and Distress Inventory (MaSQuDI-17), was produced. Parallel Analysis on the MaSQuDI-17 confirmed the presence of a single dimension; exploratory factor analysis showed salient loading for each item, explaining 58.7% of total variance. Item-remainder correlation ranged from 0.72 to 0.39 and Cronbach alpha was 0.896. Rasch analysis revealed satisfactory psychometric properties of the new scale: the rating structure performed according to expectations, model fit was good and no item dependencies emerged. The scale presented good convergent validity and scores significantly distinguished healthy subjects from OSAS or Insomnia or BSD (p < 0.001). CONCLUSIONS: MaSQuDI -17 shows good psychometric qualities, and can be used to assess the impact of sleep disorders such as Insomnia, OSAS, Central Hypersomnia and BSD on emotional stress.

Circadian Sleep Propensity and Alcohol Interaction at the Wheel.

STUDY OBJECTIVES: The study was aimed at estimating the effect of alcohol consumption, time of day, and their interaction on traffic crashes in a real regional context. METHODS: Blood alcohol concentration (BAC) data were collected from drivers involved in traffic accidents during one year in an Italian region and in a control group of drivers over the same road network. Mean circadian sleep propensity was estimated from a previous study as function of time of day. Accident risk was analyzed by logistic regression as function of BAC and circadian sleep propensity. RESULTS: BAC values greater than zero were found in 72.0% of the drivers involved in crashes and in 40.4% of the controls. Among the former 23.6% of the drivers exceeded the BAC legal threshold of 0.05 g/dL, while illegal values were found in 10.4% of the controls. The relative risk showed a significant increase with both BAC and circadian sleep propensity (as estimated from time of day) and their interaction was significant. CONCLUSIONS: Due to the significant interaction, even low BAC levels strongly increased accident risk when associated with high sleep propensity.

Efficacy of Bilevel-auto Treatment in Patients with Obstructive Sleep Apnea Not Responsive to or Intolerant of Continuous Positive Airway Pressure Ventilation.

BACKGROUND: Ventilation with continuous positive airway pressure (CPAP) is the gold standard therapy for obstructive sleep apnea (OSA). However, it was recently suggested that a novel mode of ventilation, Bilevel-auto, could be equally effective in treating patients unable to tolerate CPAP. The aim of this study was to investigate the ability of Bilevel-auto to treat OSA patients whose nocturnal ventilatory disturbances are not completely corrected by CPAP. METHODS: We enrolled 66 consecutive OSA patients, not responsive to (group A) or intolerant of (group B) CPAP treatment, after a full night of manual CPAP titration in a laboratory. Full polysomnography data and daytime sleepiness score were compared for each group in the three different conditions: basal, during CPAP, and during Bilevel-auto. RESULTS: The apnea-hypopnea index decreased significantly during CPAP in both groups; however, in the group A, there was a further significant improvement during Bilevel-auto. The same trend was observed for oxygenation indices, while the distribution and the efficiency of sleep did not differ following the switch from CPAP to Bilevel-auto. CONCLUSIONS: This study confirmed the role of Bilevel-auto as an effective therapeutic alternative to CPAP in patients intolerant of this latter mode of ventilation. Moreover, extending the use of Bilevel-auto to those OSA patients not responsive to CPAP, we showed a significantly better correction of nocturnal respiratory disturbances.