Earlier this month, I learned that I have mild sleep apnea. The path that led to my diagnosis was a bit round-about. If you remember in April, I was dealing with some increased anxiety and depressive symptoms. We increased my antidepressant and I received an as-needed anti-anxiety medication. Both were very helpful.
When my rheumatologist learned of my increased symptoms, which also included extra fatigue and daytime sleepiness, she wanted to discuss the possibility of sleep apnea. My rheumatologist ordered an overnight sleep study. The most common sleep study is the polysomnogram (PSG) which uses sensors (applied to the scalp, face, chest, limbs, and a finger) to record brain activity, eye movements, leg movements, body position, respiratory rate, heart rate, blood pressure, and blood oxygen level while you sleep.
During my night hooked up to the PSG equipment, I experienced 13 instances of apnea and 22 instances of hypopnea. When airflow is reduced by at least 80 percent, an episode of apnea is noted. Hypopnea occurs when airflow is reduced by 50 to 80 percent, accompanied by a drop in blood oxygen level. A sleep study report will indicate the number of times each occurs in total and as an index.
Apnea Hypopnea Index (AHI) is the number of apneas and hypopneas per hour of sleep. Respiratory Disturbance Index (RDI) is the number of apneas, hypopneas, and respiratory effort-related arousals (RERAs) per hour of sleep. Sleep apnea is defined as an AHI of greater than five events per hour. An RDI of 5 to 15 indicates mild sleep apnea, 15 to 30 is moderate, and more than 30 is severe.
My overall AHI was 5.4 and RDI was 12.9. The number of respiratory disturbances increased during REM sleep, giving me a RDI during REM sleep of 26.7. More disturbances also occurred when I was sleeping on my back rather than on my side. During 6.5 hours of sleep, I woke up nine times and became aroused 198 times. My arousal/awakening index was 32.09 (per hour of sleep). Wow.
For more information regarding sleep apnea (a chronic condition characterized by disrupted breathing during sleep), its symptoms, diagnosis, and treatment, please read my posts - Sleep Apnea: Is RA Connected to Sleep Apnea? (Part One) and Sleep Apnea: How is it Diagnosed and Treated? (Part Two).
Multiple Sclerosis and Sleep Disorders
The most common type of sleep apnea is obstructive sleep apnea (OSA), in which the airway collapses or becomes blocked during sleep. Loud snoring, snorting and/or gasping for air may occur as a result. Central sleep apnea, which is less common, occurs if your brain fails to send the correct signals to your breathing muscles. You are not likely to snore with central sleep apnea as your body simply makes no effort to breathe for brief periods of time. Central sleep apnea and obstructive sleep apnea can occur independently or concurrently.