Sleep Disorders Glossary - A

Abdominal Movement

Abdominal Movement is the movement of the abdomen, which reflects breathing effort and movement of the diaphragm. This is typically measured by the placement of a sensor band around the chest. Abdominal movement is recorded in diagnostic sleep studies. This measurement is used in differentiating the type of sleep apnea.

Advanced Sleep Phase Syndrome [ASPS]

Advanced Sleep Phase Syndrome (ASPS) is a disorder in which the major sleep episode is advanced in relation to the desired clock time, sleep onset occurs in early evening and as a consequence, wakefulness occurs in early morning. . The sleep phase occurs well ahead of the conventional bedtime and the tendency is to wake up too early. This disorder is more common in the elderly.

Airflow Limitation

Airflow Limitation is a Partial closure of the upper airway with reduced airflow.

Alpha-Delta Sleep

Alpha-Delta Sleep in which, Delta brainwaves (deep sleep) are mixed with alpha brainwaves (relaxed wakefulness). Alpha-delta sleep occurs with conditions such as arthritic pain, stimulant use and thyroid imbalance.

Alpha Waves

Alpha waves are a pattern of smooth, regular electrical oscillations in the frequency range of 8-12 Hz that occurs during quiet wakefulness, such as when the eyes are closed. Alpha waves are commonly detected by electroencephalography (EEG) or magnetoencephalography (MEG)

Altitude insomnia

Altitude insomnia is an acute insomnia that occurs when people go to higher altitudes. Usually accompanied by headaches, loss of appetite, and fatigue. Twenty-five percent of individuals who go from sea level to 2,000 meters will have some symptoms. Also called Acute mountain sickness, Acosta