What are some common misconceptions associated with mild hearing losses?
The mild misnomer
Mild hearing losses are clouded by the misnomer that is used to classify these levels of hearing impairment. The term ‘mild’ suggests little to no experienced impairment or handicap, resulting in a low priority for rehabilitation and amplification on the part of the patient, the consequences of which can be very high. In reality individuals with mild hearing losses often experience difficulties understanding speech especially in the presence of competing signals.
There are five main reasons for hearing-impaired individuals with sensorineural hearing loss having problems hearing. They are decreased audibility, reduced dynamic range, reduced frequency resolution, reduced temporal resolution and increased listening fatigue. Reduced audibility, reduced dynamic range and increased listening fatigue affects individuals with all levels of sensorineural hearing losses, even those with mild levels of hearing loss, whereas reduced frequency resolution and temporal resolution are believed to affect mostly increased levels of hearing loss.
The hearing loss classification by Clark ( 1981) is used worldwide and defines a mild hearing loss as having thresholds between 26 and 40 dB HL.
The mild terminology is misleading as important speech sounds become inaudible with a mild hearing loss. People with a mild hearing loss are likely to hear some sounds, but not others or part of others. In particular the softer phonemes, which are usually consonants, may not be heard. It is especially the fricatives that become inaudible with a mild hearing loss, the /f/, /s/, /th/ and /k/. The reason for this is twofold, these phonemes are weaker and they are high frequency phonemes, which is the frequency area most commonly affected by impairment. The high-frequency components of speech are weaker than the low-frequency components and because the loudness of speech mostly originates from the low-frequency components, people with high frequency hearing loss may not realize that they are hearing less of the speech signal, even when they cannot understand speech in many situations. Statements like "speech is loud enough, but not clear enough” and “if only people would not mumble” are common.
A sensorineural hearing loss increases the threshold of hearing much more than it increases the threshold of loudness discomfort, resulting in the range between the hearing threshold and the loudness discomfort being decreased. This means that for hearing-impaired individuals even with a mild hearing loss, weak to moderate sounds are not audible while loud sounds stay audible.
With hearing loss listening and understanding requires more work to understand particularly in noise. Hearing-impaired people report increased concentration effort, attention and focus, compared to individuals without hearing loss. Increased listening fatigue is likely to be a side effect of even a mild hearing loss. Increased listening fatigue is however like decreased audibility often not being noticed by the person with a mild hearing loss him- or herself.
The terminology mild hearing loss is in other words a misnomer. Mild hearing losses do not have mild consequences. A consequence of mild hearing loss is reduced audibility resulting in reduced speech intelligibility in general, but especially in noise and over distance. Another consequence is increased listening fatigue with the risk of affecting social life.
Many people with mild hearing losses are unaware of their hearing loss
There are significantly more people with mild hearing losses as compared to people with moderate, severe and profound hearing losses (World Health Organization, 2000). However, within the group of hearing- impaired individuals, people with mild hearing losses are the least likely to own hearing aids. There are many reasons for this, one being that many people with mild hearing impairment are unaware of their hearing loss. Does this mean that we as audiologists should not focus on this group of people? Absolutely not. As professionals we are aware of the consequences of mild hearing losses and the benefits of amplification and we are obliged to at least help this group of hearing-impaired people make an informed decision on whether they want amplification now or later.
What to consider when fitting mild hearing losses
People with mild hearing losses on average experience fewer hearing loss related problems in their daily life, than people with more severe hearing losses. For this reason they also on average get less hearing aid benefit. However, they DO gain benefit from amplification and this is a key message that the audiologist has to pass on to the hearing-impaired individual (Mecklenburger & Joergensen, 2009). As hearing-impaired individuals with mild hearing losses on average have less potential for hearing aid benefit it is even more important to optimize their hearing aid benefit and minimize the potential disadvantages.
Occlusion effect is one potential disadvantage of hearing aids, but with the launch of open fittings back in 2003 this is no longer an issue as open solutions now are multiple.
Numerous studies have shown that there is a lot of stigma attached to hearing aids and hearing aid users. Audiologists often tend to focus on audibility first and cosmetics second, but the hearing aid user might have it the other way around. The concern about appearance has to be taken seriously, since the hearing aids will be of no use, if the hearing-impaired person is so concerned about his or her appearance that they will not wear them. The primary concern of a hearing-impaired individual can be found in the questions he or she asks e.g. are the questions concerned around the solution provided or around the size and visibility of the device.
As with any other loss, there is several stages one goes through, when experiencing it; denial, anger, depression and finally acceptance. The audiologist will probably see more people in the acceptance phase, since the hearing-impaired person chose to do something about the problem and sought out help or information. Some of the psychosocial consequences of a hearing loss can be:
- Withdrawal to avoid embarrassment, frequent misunderstandings and inappropriate responses.
- Frustration on the part of the hearing-impaired person, but also on the part of the family.
- Loss of long distance contact with friends and family due to fatigue when having phone conversations.
- Fear that independence will be taken away, e.g. if the hearing-impaired person is elderly and suffering from additional handicaps.
- Fear that responsibilities will be taken away, e.g. in the work place.
It is imperative, that the audiologist tries to really understand the person in front of him or her to be able to help them better and provide the best possible service.
Communication strategies can be used as part of the treatment to improve hearing aid benefit. They help the hearing aid user to take responsibility of the treatment, which increases likelihood of success.
Communication strategies can also be used as a stand-alone treatment until acceptance of hearing impairment and motivation for amplification is present. Training in communication strategies can focus on training the hearing-impaired person in choosing a good listening environment e.g. rooms with good acoustics, light on the person the hearing-impaired individual wants to hear and good signal-to-noise ratio, so the hearing-impaired person is closer to the wanted signal, than to the unwanted signal or noise source. Communication strategies can also be training the hearing-impaired individual in how he or she can educate the surroundings in helping him- or her out hearing better e.g. try to speak one by one, instead of all at the same time, use gestures and natural hand signs, make sure to have the attention of the hearing- impaired person before talking, not to increase sound volume, but lower speaking tempo instead and try improving articulation. Finally, training in communication strategies is training the hearing-impaired individual him- or herself in what (s)he can do to improve hearing e.g. accept that no one hears everything, facilitate communication by being specific when asking for repetition e.g. “what time did you say your sister will visit us” instead of “pardon”, be understanding towards communication partners, who do not know what it is like to have a hearing loss and tends to forget the good communication strategies.
Clark, J. G. (1981). Uses and abuses of hearing loss classification. Asha, 23, 493–500.
World Health Organization (2000). http://www.who.int/healthinfo/statistics/bod_hearingloss.pdf
Mecklenburger, J. & Joergensen, S. (2009). Presentation at the American Academy of Audiology Conference.