Profound Hearing Impairment
Summary & Description
Definition & Classifications
- A hearing impairment is a hearing loss that prevents a person from receiving sounds through the ear. Hearing impairment refers to hearing losses of varying degrees, ranging from mild, moderate, severe to profound (ASHA, 2006). A person with a hearing threshold of 25 dB or greater is said to have hearing loss. It can affect one ear (unilateral) or both ears (bilateral), and leads to difficulty in hearing conversational speech or loud sounds. People with losses in the 35-69 dB range are labelled hard of hearing, where as those with 70 dB or higher are described as deaf or considered to have a profound hearing impairment (ASHA, 2006).
- A Profound hearing impairment is defined as hearing loss >91dB HL (Roth & Worthington, 2011). Those with profound hearing loss hear little to no sound. Profound hearing loss like any hearing impairment can be bilateral (both ears) or unilateral (one ear) (Roth & Worthington, 2011).
- According to the World Health Organization (2015) over 5% of the world’s population have a disabling hearing loss 328 million adults and 32 million children (WHO, 2015).
- Hearing loss is one of most prevalent birth defects in the US (WHO, 2015).
Types of Profound Hearing Loss
There are three major types of hearing impairment
1.) Conductive- refers to an obstruction to air conduction that prevents the proper transmission of sound waves through the external auditory canal to the cochlea (Roth & Worthington, 2011). Conductive losses do not exceed 60 dB HL so someone with a profound hearing impairment would not have a conductive loss alone but may have a mixed hearing loss (Roth & Worthington, 2011). Conductive hearing loss may be congenital or caused by trauma. A typical cause of conductive hearing loss is otitis media. Some conductive hearing loss can be treated surgically and the use of hearing aids and assistive listening devices may also be beneficial (ASHA, 2006).
3.) Mixed- occurs when hearing loss is due to a combination of problems in both the conductive and sensorineural mechanisms. Therefore damage may be in the outer ear, middle ear, and in the inner ear (Shemesh, 2010).
Common Causes of Profound HL: Acquired & Congenital
- Inherited conditions from parents
- Diseases such as Meniere’s disease or meningitis
- Infection during pregnancy such as measles or mumps
- Head Injury/Trauma
- Glue Ear
Diagnostic Criteria: When describing hearing impairment and it's implications on speech and language development, several attributes should be considered :
- Type of hearing loss (part of the hearing mechanism that's damaged).
- Degree of hearing loss
- Configuration (range of pitches or frequencies at which the loss has occurred).
- Age of onset and age of intervention (hearing aids, cochlear implant etc)