The statement above is one that Audiologists hear almost every day. While this complaint is a common one, its cause is not always so easy to determine. There are quite a number of different reasons that may give rise to such a complaint. A high-frequency loss of hearing is one potential reason, but another is the individualâ€™s Cognitive Hearing ability, often becoming especially noticeable as we age.
What do we mean when we say â€œCognitive Hearing?â€ This term refers to the complex set of brain processes that occur between the initial point when a sound is heard and the point where one is able to grasp the meaning or significance of that sound. This takes place in a very short period of time, and requires some very complex brain activity.
There are many factors involved in hearing and understanding what you hear. The sense of hearing is actually a very complex process. We hear sounds through a series of vibrations and signals sent from the nerve of the inner ear to the brain. This is where incoming speech is processed, and at this point it relates to the understanding rather than the hearing.
Below is a list of processes involved in hearing and understanding what you hear:
- Auditory Periphery â€“ converts incoming acoustic signals into physiological information.
- Listening â€“ selects information with the attention and effort of the hearer.
- Comprehending â€“ interprets all contextual, linguistic and grammatical information.
- Reacting â€“ storing in memory, reasoning and responding.
Each of these processes becomes somewhat less effective as we age. Research has indicated that when tests are performed to compare a group of adults with hearing loss to another group of adults that did not have hearing loss, both performed similarly? This result was seen both when study participants were faced with tests designed to examine their understanding of fast speech, and when examining their understanding of speech in background noise (reference: Pichora-Fuller et al., 1995). The aging brain slows down, just like the rest of our body!
The hearing impaired person has to work much harder through all phases of the hearing process. At the start there is more effort required to â€œlistenâ€ to and â€œhearâ€ the incoming speech. Very often when more effort is applied to one task, less effort is available for everything else. This â€œdivision of laborâ€ may lead to what is often referred to as â€œselective hearing.â€ The automatic reallocations of energy and resources likely tend to slow and reduce a personâ€™s ability to process incoming sounds. Persons with hearing loss must dig more deeply into their cognitive abilities in order to attempt to make sense of a compromised auditory input. And, naturally, when someone is required to process multiple incoming sounds at the same time, their understanding of these various inputs will suffer. Individuals with hearing loss are often observed to appear to have problems with recall, comprehending language, or other cognitive deficits due to the compromised sound input. These difficulties are seen as secondary to the actual loss of hearing experienced by the individual (Beck and Clark, 2009).
As audiologists, we understand that each person is a unique individual, and each personâ€™s ability to hear and understand can vary greatly. We also understand how the various factors of cognition, attention, memory, and hearing can each play a critical role in hearing and understanding. While it is true that little can be done to restore cognitive function, there are strategies that can help persons with hearing difficulties. These strategies include the use of advanced hearing aid technology designed to reduce the effort required to understand speech, and help individuals to thrive.
Processing complex speech sounds requires a physically intact listening system and a well- managed listening strategy. Human brains are highly amenable to training, habilitation, and rehabilitation due to neuroplasticity (the ability of the brain and nervous system to change structurally and functionally as a result of input from the environment). However, the longer a person with hearing loss goes without proper stimulation of their auditory system, the longer it will take for them to adjust to better hearing. Weâ€™ve all heard the saying â€œuse it or lose it.â€Â It definitely applies to hearing. Donâ€™t put off better hearingâ€¦your brain will thank you!