Apnea Hypopnea Index Posted February 12, 2016 by Robert Hooper The number of apneas and hypopneas that occur during an hour of sleep. Related Articles: Apnea – A Word with Many UsesGlossary: AHIWhat is the AHI (Apnea Hypopnea Index)Hypoglossal Nerve Stimulator« Back to Glossary IndexRelated Terms:Term: Sleep