The Apnea-Hypopnea Index (AHI) is a term that we regularly read in sleep study (polysomnography or home sleep test) reports. For many years, in looking at sleep study reports for my patients, I didn’t really understand what the Apnea-Hypopnea Index was exactly. And, when a report said that my patient’s AHI was 5.3 or 10.6 or whatever,…