ABSTRACT
The American National Standards Institute (ANSI) defined hearing loss (HL) as the difference from the normal ability to detect sounds relative to its established standards.
Hearing impairment is usually classified by site of lesions into two main groups, conductive and sensorineural. More specific definitions of damage localization along the auditory pathway, according to a better diagnostic evaluation, provide a more detailed subdivision of the impairments. The “sensorineural” term is related to disease or deformity of the inner ear/ cochlear nerve with an air-bone gap <15 dB; “neural” refers to pathology of the cochlear nerve; “sensory” means a cochlear disease or deformity. A combined involvement of the outer/middle ears and the inner ear, characterized by >20 dB HL in the bone conduction and associated with >15 dB air-bone gap, is defined as “mixed” impairment. A “central” impairment is due to a disease localized in the central nervous system above the cochlear nerve. This classification appears to be useful in clinical practice. However, a nosological point of view does not fully respect the impact of hearing impairment on individual participation in social life and on quality of life, when health intervention must be planned.
