Diagnosis
In a systematic review of published evidence, the United States Preventive Services Task Force in 2017 concluded that there was uncertainty about the accuracy or clinical utility of all potential screening tools for OSA, and recommended that current evidence is insufficient to assess the balance of benefits and harms of screening for OSA in asymptomatic adults.The diagnosis of OSA syndrome is made when the patient shows recurrent episodes of partial or complete collapse of the upper airway during sleep resulting in apneas or hypopneas, respectively. Criteria defining an apnea or a hypopnea vary. The American Academy of Sleep Medicine (AASM) defines an apnea as a reduction in airflow of ≥ 90% lasting at least 10 seconds. A hypopnea is defined as a reduction in airflow of ≥ 30% lasting at least 10 seconds and associated with a ≥ 4% decrease in pulse oxygenation, or as a ≥ 30% reduction in airflow lasting at least 10 seconds and associated either with a ≥ 3% decrease in pulse oxygenation or with an arousal.To define the severity of the condition, the Apnea-Hypopnea Index (AHI) or the Respiratory Disturbance Index (RDI) are used. While the AHI measures the mean number of apneas and hypopneas per hour of sleep, the RDI adds to this measure the respiratory effort-related arousals (RERAs). The OSA syndrome is thus diagnosed if the AHI is > 5 episodes per hour and results in daytime sleepiness and fatigue or when the RDI is ≥ 15 independently of the symptoms.
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.