In the field of audiology (the study of hearing and deafness), acuity refers to keenness or sharpness of hearing, usually measured as the ability of a person to detect the p…resence of sound 50% of the time under ideal listening conditions..
Thus, a person who has no loss of hearing acuity will detect the presence of very weak or soft sounds; someone whose acuity is diminished will not detect the presence of sound until it is more intense..
Stated another way: When audiologists do a simple hearing test and find that a patient has a "hearing loss," they usually mean that the patient did not detect sounds until the intensity of those sounds was increased. That finding represents a loss of hearing acuity ..
Acuity is usually measured for perception of pure tones (simple sounds produced electronically) or speech. But it can be measured for any kind of sound, including music or noise..
Acuity is distinguished from comprehension, which refers to how well people can understand speech that they are able to hear. Thus, some people are able to detect the presence of speech but are not able to understand it at all well, even when it sounds loud enough to them. In that instance, the speech is loud enough; it just isn't clear. ( Full Answer )