What Is an Audiologist?
What Is an Audiologist?The history of hearing loss is probably as long as that of mankind itself. There are writings from 1550BC that refer to discussions of possible treatments for deafness – some dating from even earlier times. Over a thousand years later, a Roman physician became the first to differentiate between hearing disorders, although perceiving them as limited to excessive wax build-up, foreign bodies, or ulcers in the ear canal. While various assisted listening devices began appearing as early as the 13th century, it was not until the Second World War that the study of hearing became the speciality of a new breed of healthcare professional – the audiologist.
The technology with which to quantify hearing loss was actually developed in the 1920s, but it was the soldiers returning from the next major conflict and affected by noise-induced hearing loss who provided researchers with sufficient subjects for a mass study. In turn, this created the need for trained professionals to conduct the necessary examinations. While the otolaryngologist or ENT surgeon is a medical graduate specialising in the medical and surgical treatment of the various pathologies affecting the ear, nose, and throat, the role of the audiologist is limited exclusively to the evaluation and management of hearing loss. He or she is not qualified to perform surgery or to prescribe medication, but may recommend over-the-counter products, as well as supply and fit hearing aids.
The minimum qualification required by these healthcare professionals for registration with the Health Professions Council of South Africa (HPCSA) is an appropriate 4-year bachelor’s degree. Currently, they may select from a BSc or BA in Audiology, a Bachelor of Communication in Pathology, a BA in Speech and Hearing Therapy, or a Bachelor in Speech-Language Pathology and Audiology. In addition, a number of universities offer research programmes leading to a master’s degree or doctorate. Credentials apart, what are the responsibilities of an audiologist?
Much of the day-to-day tasks of these hearing specialists is likely to be spent conducting audiograms. The technology mentioned earlier refers to an instrument known as the audiometer. Its function is to provide a hearing profile of the subject under examination, which identifies those wavelengths at which sound perception is impaired and the extent of the impairment. The audiometer has evolved to become a sophisticated recording device. It can display a patient’s hearing profile in a graphical format that can easily be interpreted by an experienced operator. This, however, raises a question. Why does an audiologist require this information?
Whereas a hearing aid was once a simple amplification device that was designed to treat all audible frequencies uniformly, audiometry revealed that hearing loss does not generally affect all frequencies equally. This realisation has led to the design of newer models which can be tuned so as to enhance only those frequencies that are seen to be impaired and to the extent indicated as necessary by the findings of an audiogram. As a result, the wearer experiences a more balanced sound environment, closer to that experienced by a hearing individual.
Prior to the hearing test, an audiologist will first conduct a physical examination of the ear. He or she has been trained to recognise the signs of infection and other pathologies that might necessitate referring a patient to a GP or an ENT specialist. Even when the audiogram is complete, there are additional diagnostic procedures to be performed. Malfunctions within the outer and middle ear regions result in deafness due to inefficient conduction of sound, while damage within the inner ear results in a loss of the sensory function necessary to convert the motion of the cochlear fluid into modulated nerve signals for onward transmission to the auditory centres in the brain.
To differentiate conductive from sensorineural and mixed deafness, the audiologist must perform the Rinne and Weber tests. Both tests are painless and non-invasive in nature. They involve various placements of a vibrating tuning fork to determine in which position of the fork or in which ear the sound appears to be loudest. The findings of these additional tests can help the healthcare professional to identify the most suitable approach with which to manage a patient’s auditory impairment.
In cases of severe to profound sensorineural hearing loss, the sole option may be a cochlear implant. Having first confirmed that a conventional hearing aid provides no benefit, the audiologist will then refer the patient to an ENT specialist for evaluation as a suitable candidate for cochlear implantation.