According to the American Association of Sleep Medicine, daytime sleepiness is determined as mild, moderate and severe depending on its impact on social life. Daytime sleepiness can be assessed with the Epworth Sleepiness Scale (ESS), a self-reported questionnaire on the propensity to fall asleep or doze off during daytime. Screening tools for OSA itself comprise the STOP questionnaire, the Berlin questionnaire and the STOP-BANG questionnaire which has been reported as being a very powerful tool to detect OSA. Criteria
According to the International Classification of Sleep Disorders, there are 4 types of criteria. The first one concerns sleep – excessive sleepiness, nonrestorative sleep, fatigue or insomnia symptoms. The second and third criteria are about respiration – waking with breath holding, gasping, or choking; snoring, breathing interruptions or both during sleep. The last criterion revolved around medical issues as hypertension, coronary artery disease, stroke, heart failure, atrial fibrillation, type 2 diabetes mellitus, mood disorder or cognitive impairment. Two levels of severity are distinguished, the first one is determined by a polysomnography or home sleep apnea test demonstrating 5 or more predominantly obstructive respiratory events per hour of sleep and the higher levels are determined by 15 or more events. If the events are present less than 5 times per hour, no obstructive sleep apnea is diagnosed.A considerable night-to-night variability further complicates diagnosis of OSA. In unclear cases, multiple testing might be required to achieve an accurate diagnosis. Polysomnography
Nighttime in-laboratory Level 1 polysomnography (PSG) is the gold standard test for diagnosis.
More precisely, attention and memory deficits seem to result from sleep fragmentation, while deficits in global cognitive function (executive function, psychomotor function, language abilities) are more related to hypoxia or hypercarbia which accompanies the obstructive events during sleep. However, no consistent correlation has been found between the degree of cognitive impairment and the severity of the sleep disturbance or hypoxia. These impairments may improve with an effective treatment for OSA, such as continuous positive airway pressure (CPAP) therapy. Driving a motor vehicle is an example of a complex task that relies on drivers cognitive abilities, such as attention, reaction time and vigilance. Very brief moments of inattention called microsleep events could be an indicator for daytime vigilance impairment, although these may not be present in all drivers with obstructive sleep apnea. Behavioral consequences
The hyperactivity and difficulties in emotional regulation found in pediatric patients (children) are not reported in adults. OSA in adults is nevertheless associated with personality changes and automatic behavior. The biggest impact of OSA is the excessive daytime sleepiness (EDS), reported in approximately 30% of OSA patients. EDS can be caused by the disturbance of sleep quality, the insufficient sleep duration or the sleep fragmentation and it is responsible for further complications as it may lead to depressive symptoms, impairments of social life and decreased effectiveness at work. Studies have shown that those consequences of EDS can be improved following a CPAP treatment.