Polysomnogram

Part of speech: noun

Definitions

1. A multi-channel recording of brain waves, breathing, heart rate and other body functions made while a person sleeps, used to diagnose sleep disorders
2. The detailed record made during overnight sleep that tracks brain activity, respiration, muscle movement and heartbeat to help identify sleep problems
3. A test result capturing many physiological signals throughout the night of sleep, often used by clinicians to investigate conditions such as sleep apnea

Etymology: Polysomnogram is a plain modern compound, built from three Greek-derived pieces: "poly-" (many), "somno-" (sleep, from Latin "somnus") and "-gram" (a written or recorded record, from Greek "gramma", a letter or drawing). Put together, it names a recording of many physiological signals taken during sleep, such as brain waves, eye movements, muscle activity, heart rhythm and breathing. The word is a technical coinage, not an ancient one. The ancient Greeks and Romans had no sleep laboratories or electrodes, so the term was assembled in modern times from classical building blocks, following the pattern of older medical words such as "electrocardiogram". Its "-gram" element lets it sit alongside a family of recording terms, while "somno-" marks it as a sleep study.