Hearing Loss By Lawrence R Lustig, MD, Columbia University Medical Center and New York Presbyterian Hospital Reviewed / Revised Jul 2022 | Modified Sep 2022 View Patient Education Pathophysiology Etiology Evaluation Treatment Single-Sided Deafness Treatment of Hearing Loss in Children Prevention Geriatrics Essentials: Hearing Loss Key Points More Information Topic Resources Audiogram of right ear in... Cochlear Implant Differences Between Sensory... Congenital Causes of Hearing... Some Causes of Acquired Hearing... Sound Levels Worldwide, about half a billion people (almost 8% of the world's population) have hearing loss (1).