What is the definition or description of: sleep study?

Sleep study: Also called polysomnography, is a multi-parametric test used in the study of sleep & also as diagnostic tool in sleep medicine. Polysomnogram records the biophysiological changes that occur during sleep. It monitors brain activity (eeg), eye movements (eog), muscle activity (EMG) , respirations, pulse oximetry & heart rhythm (ekg) during sleep. It is used to diagnose or rule out sleep disorders.

Sleep observation: An overnight recording of a persons sleep including sleep stages, time awake vs. Asleep, oxygen saturation, blood pressure, breathing effort, snoring, arousals and leg movements. Conducted in a sleep center is considered an attended study and at home it is considered an unattended study. At home studies do not record as much information as an attended study in a sleep center.

AHI: Apnea hypopnea index is defined as the number of these events recorded in a psg test per hour of sleep. It is the standard by which a board certified sleep specialist uses in diagnosing the level of obstructive sleep apnea and makes recommendations of treating a particular condition.

Sleep Study: Sleep study is usually an in lab overnight procedure to diagnose sleep apnea, periodic leg movement disorders, rem behavior disorder etc. It uses multiple channels to measure brain and heart electrical activity, oxygen levels, muscle movements etc.