Sleep apnea is a sleep disorder mainly involving breathing difficulties. Three main types of sleep apnea are: Obstructive Sleep Apnea (OSA) – the most common form, due to relaxation of the muscles in the back of the throat; Central Sleep Apnea (CSA) – when the brain fails to transmit signals to the muscles that control breathing, and Complex sleep apnea syndrome – a combination of OSA and CSA. Common symptoms associated with sleep apnea include loud snoring, gasping for air during sleep, a pause in breathing while sleeping, morning headache, difficulty staying asleep (insomnia), excessive daytime sleepiness (hypersomnia), and waking up with a dry mouth. Factors that increase the risk of sleep apnea include obesity – fat deposits around the airway obstruct breathing; neck circumference – thicker necks might have narrower airways; gender (males are more prone); age (usually affects older adults); genetics; use of alcohol, sedatives or tranquilizers – they relax the throat muscles; smoking – may increase the amount of inflammation in the upper airway; nasal congestion; and medical conditions such as congestive heart failure, high blood pressure, type 2 diabetes, and stroke. A sleep specialist can help to diagnose sleep apnea. Tests to detect sleep apnea include: Nocturnal polysomnography – a device is attached to the patient, that measures heart, lung and brain activity, breathing patterns, arm and leg movements, and blood oxygen levels while asleep; Home sleep tests – an at-home kit to measure your heart rate, blood oxygen level, airflow and breathing patterns. Diagnosis may require an evaluation by an Otolaryngologist to rule out ear, nose and throat conditions, as well a cardiologist and neurologist for heart and neurological conditions. The main treatment for sleep apnea is continuous positive airway pressure (CPAP) – a machine that delivers air pressure through a mask while sleeping, to keep the upper airway passages open, preventing apnea and snoring. Other airway pressure breathing devices are expiratory positive airway pressure (EPAP), bilevel positive airway pressure (BiPAP or BPAP), and adaptive servo-ventilation (ASV). Surgery is usually a last resort, which may include: tissue removal – from the rear of the mouth and top of the throat, and in some cases the tonsils and adenoids; tissue shrinkage – shrinking the tissue at the rear of the mouth and the back of the throat using radiofrequency ablation; jaw repositioning; implants; nerve stimulation; and tracheostomy (creating a new airway passage).