An audiologist, according to the American Academy of Audiology, "is a person who, by virtue of academic degree, clinical training, and license to practice and/or professional credential, is uniquely qualified to provide a comprehensive array of professional services related to the prevention of hearing loss and the audiologic identification, assessment, diagnosis, and treatment of persons with impairment of auditory and vestibular function, and to the prevention of impairments associated with them.
Reasons for the lack of hearing screenings is in part due to limited personnel and financial resources, according to McPherson and Olusanya (2008).
These actions include: promotion of immunization against known causes of hearing loss (e.g., measles, mumps, and rubella); improved care of mothers before and during child delivery; and education on the use or misuse of ototoxic drugs (McPherson & Olusanya, 2008[4]).
According to the World Health Organization (1971),[6] screening is a "medical investigation that does not arise from a patient’s request for advice for specific complains.
Similarly Harford et al. (1978)[7] states, "screening is a process by which individuals are identified who may have disease or disorders that are otherwise undetected" and which many have "findings of asymptomatic cases" (Haggard & Hughes, 1991).
Two objective screening tests available for use in infants are otoacoustic emissions (OAEs) and auditory brainstem response (ABR).
McPherson and Olusanya (2008)[4] write, "evidence from ongoing infant hearing screening programs has shown that these tests are acceptable to parents because they are not invasive, painless and quick to administer.
Lastly, it is recommended that the two-stage screening protocol be performed on newborns prior to hospital discharge in order to decrease the number of infants lost to follow-up care.
Challenges faced in hospital-based screenings may include: excessive ambient noise causing higher referral rates; a long queue of babies may results on parents growing impatient and thus leaving prior to having their baby screened; and may fail to reach a significant number of newborns that are born outside of hospitals, which are common in developing countries (UNICEF, 2005[18]).
Fortunately, "routine childhood immunization is perhaps the most well-established public health program globally, due to substantial technical/financial support it receives yearly from UNICEF, WHO and several donor agencies/partners" (McPherson & Olusanya, 2008).
Furthermore, Lin et al. (2004),[21] Kapil (2002),[22] and Bantock and Croxson (1998)[23] speculate that hearing screenings may even be performed at infant welfare clinics and other child health programs.
When considering universal newborn hearing screenings, an important ethical requirement is the delivery of equitable access to all babies.
Targeted screening has been shown to identify approximately 50% of babies with moderate to profound hearing loss (Vohr et al., 2000;[24] Watkin et al., 1991[25]).
Examples of programs in developing countries include Columbia, Costa Rica, Cuba, Nicaragua, Panama, Kenya, Ghana, and Jamaica (Madriz, 2001;[29] Macharia, 2003;[30] Amedofu et al., 2003;[31] Lyn et al., 1998[32]).
The three recommended tests in school-based-screenings for developing countries are otoscopy, pure-tone audiometry screening, and otoacoustic emissions (OAEs).
Additionally, otoscopy does not require a great deal of expertise beyond basic training and is useful to refer a child when the tympanic membrane cannot be visualized due to occlusion of the external auditory meatus by cerumen.
Pure-tone audiometry screening, in which there is typically no attempt to find threshold, has been found to accurately assess hearing status in children six years and older, when trained health workers in the community of rural Bangladeshi village used a simple condition play response procedure (Berg et al., 2006[42]).
However, 500 Hz has been found to identify the auditory impact of otitis media with effusion in children and should be included at 25 dB HL when permitted by ambient noise levels (WHO, 1997).
OAEs are an objective tool that can be used to measure the integrity of the outer hair cells in the cochlear; however, test results below 2000 Hz can be adversely affected by high levels of ambient noise in the school environment (Nozza, 2001[46]).
According to the World Health Organization (WHO, 2013[47]), approximately 360 million people worldwide have a hearing loss greater than 40 dB HL.