Spatial Hearing Loss
If you have trouble understanding or tracking conversation in a room when there is background noise from multiple conversations, television, or other environmental factors, you could be experiencing spatial hearing loss. Spatial hearing loss, or spatial deficit disorder, is a type of hearing loss that makes it hard to track conversations or tell from what direction sounds are coming from. Often associated with a unilateral sensorineural hearing loss, spatial hearing is dependent on the ability of both ears to hear sounds equally. A spatial deficit is believed to occur in the auditory pathways of the brain beginning in the inner ear. With spatial hearing, it really is true that two ears are better than one. Spatial hearing helps us identify where sound originates from in environmental situations. For individuals with normal hearing, spatial identification allows them to understanding speech in the midst of complex environments when speech comes from one source and background sounds from another direction.
All inner ear malfunctions are known as sensorineural hearing loss, or nerve deafness. Children diagnosed with CAPD, or a central auditory processing disorder, often suffers from sensorineural hearing loss presenting as a spatial deficit. These children find it difficult to track and process speech in a classroom environment. It may not be apparent that these children are technically deaf.Few people realize that most deaf people have some level of residual hearing. Deaf children may adapt their communication or interactions to accommodate for their inability to track speech by withdrawing or acting out in ways society deems unacceptable. It is important that children with attention or behavioral problems have their hearing tested as part of the early evaluation process. Undiagnosed hearing loss causes delayed communication, interferes with social bonding, and delays speech and sound recognition. The sooner loss of hearing is diagnosed and treatment or intervention is begun, the better the chances a child will progress normally in social bonding, communication, speech development, and sound recognition. Hearing loss causes include medications, insufficient oxygen supply during the birth process, illness or trauma. When hearing loss causes cannot be identified, it is called Idiopathic deafness.
Spatial deficits may also present later in life as audio nerve damage occurs for a variety of reasons including the normal aging process. Age-related spatial hearing deficits may occur because of medications, injury, vascular insufficiencies, or underlying medical conditions and diseases. The difficulty of hearing speech in noise often leads to frustration, miscommunication, and misunderstanding when older adults are not able to follow a conversation. As a result, they may withdraw from social activities and suffer from depression. Unfortunately, if an individual is hard of hearing due to spatial deficiencies, typical hearing aids may only make the problem worst. A unilateral hearing loss may be a mixed hearing loss involving conductive hearing loss as well as spatial hearing loss. Conductive hearing loss that is diagnosed and treated early may often be cured or greatly improved allowing an individual to adapt to spatial hearing deficits more easily. Conductive hearing loss occurs within the outer or middle ear and does not involve the auditory nerves affected by sensorineural types of deafness.
Sudden hearing loss may be either conductive or sensorineural. A loss of hearing that is noticed within a twenty-four to seventy-two hour span needs to be evaluated immediately. Sudden hearing loss involving the middle ear may be due to illness, infection, or blockages that respond well to early treatment. If sudden hearing loss is not quickly diagnosed and is caused by an infection or other underlying illness, it could progress to inner ear involvement permanently damaging auditory nerve pathways and resulting in permanent deafness or spatial hearing loss. A person experiencing sudden changes in hearing involving unilateral hearing loss has an increased risk of spatial deficit.
Background information about spatial hearing indicates it evolved as a survival mechanism. In the past, it was often a matter of safety to be able identify sounds quickly and know where those sounds were coming from. Today spatial recognition of sounds is also necessary to navigate communication and identify the direction from which sounds are coming. Human spatial hearing involves a series of processes we take for granted until it become obvious there is a problem in tracking conversations over background noises. Because the deficit is within the auditory nerve pathways within the brain, typical closed type hearing aids do not help. New research has led to the development of a different hearing aid concept. This involves new microphone arrangements in the form of a necklace. These new microphones may soon be available to aid in spatial hearing loss.