While there are a number of obvious symptoms OSA suffers typically experience including: loud & excessive snoring, high blood pressure, daytime sleepiness, morning headaches, pauses in breathing during sleep, waking up gasping for breath and weight gain. There really is only one way to definitely diagnose it, by taking an overnight sleep study, also called a Polysomnography (PSG). An overnight sleep study is a comprehensive recording of the bio-physiological changes that occur during sleep. The polysomnogram, or PSG, is typically performed at night in a hospital or sleep lab facility, or due to advances in technology patients may now opt to have one at home. A PSG typically monitors a between five and twelve body functions including brain wave activity, eye movements, muscle activity/tension, heart rhythm, achievement of various sleep stages, oral & nasal airflow and respiratory effort/efficiency during sleep.