Introduction
This morning we're going to talk about some considerations in hearing aid fitting for older adults. We'll talk about two areas - first, temporal processing and speech perception by older adults and the implications of those changes for hearing aid processing; and second, how we can encourage hearing aid uptake in this population.
The context in which I'm going to talk about this today is the following: If we have a 58 year old and an 83 year old who present to our clinic both with the same audiogram, is the hearing aid fitting going to be the same? The main question is whether hearing aid fitting practices need to differ by the patient's age, or whether hearing loss is simply hearing loss and age should not really factor into the hearing aid selection and fitting process.
What Do Older Adults Say They Want from Hearing Aids?
A recent study examined this question by asking 200 hearing aid users, age 15 to 91 years, about the importance of various attributes of hypothetical hearing aids (Meister & von Wedel, 2003). From that sample, the researchers compared a group of older adults (approximately 75 years old) to younger adults (45 years old) to determine what older adults want from hearing aids. They found that both age groups rated as equally important the following attributes: understanding of speech in quiet, understanding of speech in noise, sound quality, localization, and feedback control. In other words, those were fairly standard wants and needs from hearing aids across the ages. The one difference found between the two groups was that older adults rated handling, or ease of use, as more important.
Based on this study, if we ask ourselves whether younger adults and older adults can be considered the same when it comes to hearing aid attributes, the answer is, mostly. Some features that might make handling easier for older adults, include the style of the hearing aid, for example. In general, the In-the-Ear (ITE) style is easier to manipulate than a Behind-The-Ear style (Upfold, May, & Battaglia, 1990), as long as the battery is large enough to see and insert properly. We might also consider alternatives to hearing aids such as hardwired personal amplifiers that might be easier to handle and manipulate. For older adults, automatic processing in the hearing aids may be a consideration to facilitate ease of use. Automatic processing can reduce the need to switch programs, to manually switch to directional mode, to find the t coil setting or to even fiddle with the volume control wheel.
Age Related Hearing Loss (ARHL)
When considering whether hearing aid fitting needs to differ by age it is important to look at the characteristics of age related hearing loss (ARHL). Most of us are familiar with the audiometric threshold changes that occur with age and lead to a loss of audibility, and that is the deficit we are trying to remediate with hearing aids with older adults. In addition, there are some age related changes in terms of temporal processing and speech processing that might make hearing aid fitting different for older adults than younger adults.
Temporal Processing
Let's examine a few different temporal tasks that have been studied in younger and older adults to see how they might differ and if there are any age effects on these tasks.
Gap detection.
The first task is a simple gap detection task. The task for the listener is to identify whether or not there is a gap present between two signals. In this task, a tone is presented to a listener, and it may either be continuous (Figure 1, Interval 1), or it may have a brief silent gap inserted in the middle of the signal (Figure 1, Interval 2).
Figure 1. Illustration of a gap detection task, where a continuous signal is presented in Interval 1, and a signal with a brief silent gap inserted in the middle is presented in Interval 2. The listener's task is to identify in which interval the silent gap occurred.
The longer the gap needed for correct identification, the poorer the listener's gap detection threshold. Perhaps not surprisingly, elderly listeners need a longer gap than young listeners with normal hearing to correctly identify the interval, but there is also a lot of individual variability among older adults (Moore, Peters, & Glasberg, 1992). On this task, we can say that older adults are not going to be the same as younger adults in terms of hearing aid fitting and I'll discuss how this might impact our choice of hearing aid processing in just a moment.
Duration discrimination.
The second temporal task we can consider is duration discrimination. The task here is to identify whether two tones or two signals have different durations. For very brief tones (i.e. 40 ms) there is no age effect (Phillips, Gordon-Salant, Fitzgibbons, Yenii-Komshian, 1994). For longer tones (i.e. 250 ms) older adults need a longer duration difference in order to hear that there even has been a difference (Fitzgibbons & Gordon-Salant,1994). So for this task, we see age differences depending on the duration of the tone: for brief tones, younger and older adults are the same, while for longer tones there are differences across age.
Amplitude modulation.
The third and final temporal task I'm going to consider today is amplitude modulation. For this task, the listener's job is to identify whether or not there is amplitude modulation within a signal.
The two test signals shown in Figure 2 are continuous, except for a modulation that occurs between 1 - 1.5 seconds in time. The modulation in the signal at the top of Figure 2 has a larger depth, while the signal at the bottom has a lot less modulation depth. The signal at the bottom, with less modulation depth, would be much more difficult for the listener to detect. In an amplitude modulation task, the amount of modulation depth that's required for the listener to detect that there is modulation present in that signal is considered the threshold.
Figure 2. Two test signals in an amplitude modulation task. The signal at the top of the figure contains a modulation with greater depth than that in the signal below.
To date, no clear studies have been able to successfully separate age effects versus hearing loss effects on these tasks. For example, if a study included older listeners with hearing loss and younger listeners with normal hearing, it would be difficult to discern if any differences noted were caused by just changes in the hearing thresholds or by other age related change. However, the evidence does suggest that older adults likely need greater modulation depth than younger adults. Therefore, for this task older adults are probably not the same as younger adults.
To summarize, we've seen that temporal processing on several different tasks is impaired with age independent of hearing threshold. Therefore, there are some changes with age that need to be considered beyond just the thresholds on the audiogram. While the relationship between temporal processing and speech recognition is not fully understood, we can suspect that some of the deficits in temporal processing might explain some changes in speech recognition for older adults.
Speech Processing
Simple speech v. complex speech.
Turning to speech recognition, let's first examine some of the situations where older adults have more difficulty than younger adults. Then, we'll determine if this difficulty can be explained simply by the threshold changes of older adults or whether other factors are involved, such as differences in temporal processing.
The first situation to consider is simple speech tasks, or listening to speech in quiet that has not been distorted in any way. In these situations, any changes in perception are mainly affected by audibility. So if an older adult performs poorer than a younger adult, that difference is likely explained just by the differences in the audiometric thresholds. The next situation is complex speech, or speech in a background of temporally-modulated noise, speech in a background of meaningful noise, or reverberance. With complex speech, differences in perception are not explained by audibility alone. In other words, with older adults, speech recognition on these tasks decreases above and beyond what we would expect just from their threshold changes. Therefore, in terms of speech recognition for simple speech, younger and older adults seem to perform rather similarly. A hearing loss is just a hearing loss on these tasks, regardless of age. For complex speech, older adults seem to have particular processing issues that might impact their recognition of speech above and beyond their hearing loss, and that will have some indications in terms of hearing aid fitting.
Gordon-Salant and Fitzgibbons (1993) examined how reverberation time and age affected speech perception. In terms of complexity, listening to signals with shorter reverberation times would be a simpler task, while listening to signals with longer reverberation times would be a more complex listening task. This study included young and older listeners with hearing loss and with normal hearing. With lower reverberation times, there is very little age effect; younger and older adults with normal hearing perform very similarly and have very high recognition scores, and young and older adults with hearing loss perform similarly. As reverberation time gets longer, we start to see a clear separation of age groups independent of hearing loss - younger listeners with normal hearing have reduced performance and older listeners with normal hearing are even more affected. Hearing loss adds even greater difficulties, particularly for older listeners with hearing loss. There seems to be a cumulative effect of both aging and hearing thresholds for this complex listening task.
The interesting question to me is why is simple speech is unaffected? If there are changes happening in the aging auditory system, why isn't simple speech affected? One reason for this is that there are multiple acoustic cues to the identity of each speech segment. If there is damage in the auditory system such as threshold changes leading to loss of audibility, older listeners can turn their attention to other available acoustic cues within the speech signal itself. In a complex listening situation, such as where there is background masking noise, the redundancy of those acoustic cues is reduced. The listener can't turn to other cues to compensate for the ones that are missing.
Figure 3. Spectrogram showing two primary cues, gap and release burst, that signal the presence of a stop consonant.
Figure 3 contains a spectrogram for a word (I believe it is the word "stop"). Shown here are the two primary cues that signal the presence of a stop consonant such as p, t, or k. The two cues are the silent gap and the presence of a release burst of noise. Young listeners with normal hearing can trade off those two cues, in other words, they can use one or the other to detect the presence of a stop consonant.
Repp (1984) studied the length of gap needed to detect a stop consonant and found that if listeners only have the silent gap and not that second cue of the release burst they can still detect the presence of a stop consonant at very high rates. However, when they are given the release burst, they only need a shorter gap to detect that there is a stop consonant present. Therefore, when there is a burst present they need less of the cue from the gap than when there is no burst present. This is how younger listeners with normal hearing in effect trade off the cues in speech.
How Do Older Adults Deal with Missing Speech Cues?
Since we're talking about older adults today, let's examine how they deal with missing speech cues. To do this, I'd like to play an audio clip of a word that has no gap in it.
Most people will hear the word "seed". Now let's listen to that same word with an audio gap inserted in it.
Many people will hear "speed" as if a /p/ were inserted in the word. Just by inserting a silent gap, we are able to change the perception of the word from "seed" to "speed", even though the second word did not have a release burst typical of a /p/ sound.
We did a similar task with older adults to see how they could use the silent gap and the release burst to detect the presence of a stop consonant. We tested six older listeners (mean age 74.1 years, SD = 2.1) and six younger listeners (mean age 23.6 years, SD = 4.1), both with normal hearing. We presented words that were recordings of either "speed" or "seed" and we varied the gap length and the release burst in order to provide a continuum of ambiguous words that could be heard as "seed" or "speed" to see how older adults performed in weeding out those two cues.
We found that younger listeners don't need a very long gap at all when they have the full release burst in order to hear that the stop consonant is present. For these younger listeners, when we take away that release burst, they need quite a bit longer gap in order to hear that there is a stop consonant present. For older adults we find that even with the release burst they need a slightly longer silent gap to hear that the stop consonant is present. When the release burst is taken away, older adults also need a longer gap in order to hear that there is a stop consonant present. But otherwise, the pattern is the same for older and younger listeners. So for older listeners in this case, as long as the cue is strong enough, they can still trade cues off the way younger adults do.
Implications for Amplification
Now, we'll consider all of this information together in order to derive some general principles for choosing hearing aids for older adults.
In general, with hearing aids we want to choose processing that is going to restore audibility as much as possible without distorting the speech signal. This will help ensure that the different acoustic cues of speech are still available and audible to older listeners.
Acoustic Changes of WDRC
To illustrate the balance between audibility and distortion I want to talk about the case of wide dynamic range compression, WDRC. In the spectral domain, compression increases audibility and increased audibility is associated with benefit (Jenstad, Seewald, Cornelisse, & Shantz, 1999; Jenstad, Pumford, Seewald, & Cornelisse, 2000; Souza & Bishop, 1999, 2000; Souza & Turner, 1998, 1999). When a speech signal becomes audible, and a person can now hear it, they are more likely to be able to understand it. In the temporal domain, compression reduces fluctuations in the temporal envelope (Boothroyd, Springer, Smith, & Schulman, 1988; Verschuure, et al., 1996). This could be considered a distortion. The degree of change is going to depend on the type of compression, i.e. whether it is fast-acting versus slow-acting compression.
Figure 4 shows a waveform for speech that has been processed with different release times. The waveform for unprocessed speech is at the top of the figure, the middle waveform is processed with a fast release time, and the bottom waveform is processed with a slow release time.
Figure 4. Speech waveform processed with different release times.
First, let's listen to the unprocessed speech.
Now, let's listen to the example for the fast release time and pay close attention to the fricatives. These low intensity consonants are going to sound slightly noisier so there will be slight subtle differences to our ears than what we heard in the unprocessed signal.
With the slow release time we've essentially preserved the amplitude envelope, so it should sound very similar to unprocessed speech.
In summary, the main change to notice here between these signals is a slight noisy characteristic for the fast release time. If we focus in to the level of a single syllable, we can see how this plays out.
Figure 5. Intensity contour of the syllable /ip/. Adapted from Jenstad & Souza, 2005.
Figure 5 shows the temporal envelope of the syllable /ip/. The syllable gap and release burst are noted on the figure. The original unprocessed syllable is noted by the blue line and the red line indicates the compressed syllable. In this case, compression hasn't changed the gap at all as you'll notice the blue and red lines overlapping during the gap. But compression has, in fact, enhanced the release burst.
Acoustic Effects and Older Adults - Study
Purpose.
The big question is, are these acoustic effects significant for older adults? To look at this question, we conducted a study that investigated whether speech recognition decreases as distortion increases, and whether these effects change across age (Jenstad, 2006). We compared Young-Old versus Old-Old adults. We also wanted to look at how these effects change when we remove some of the redundant acoustic cues of speech, and force the listener to stay focused in on one cue or another.
Participants.
The Young-Old group had 11 participants, age 62 to 74 years. The Old-Old group had 14 participants, age 75 - 88 years. There were a few reasons why the dividing point for the groups was age 75 years. One reason is because some of the age effects that I have discussed today tend to be more prominent over the age of 75. Therefore, there are differences between a 60 year old, a 70 year old and an 80 year old. The other reason for using 75 years as the dividing point between the groups is that it allowed for better control of hearing loss, so we were able to find two groups of listeners with pretty much identical average audiograms. This means that if we saw any age differences between the two groups we would know that they were due to age effects and not simply hearing loss effects.
Method.
We chose materials that were fairly low context so that listeners could not use a lot of top down processing or contextual cues to fill in what they might be missing from the acoustics of the signal. We used the SPIN sentences in quiet. Testing was conducted in the following listening conditions: with WDRC, using four settings that resulted in different amounts of alteration to the temporal envelope; with the full acoustic information ("normal"); and with alternate segments removed from the signal. Figure 6 shows the stimuli.
Figure 6. Three different stimuli used in Jenstad, 2006 study.
At the top of Figure 6 is the normal rate stimulus. In the middle of the figure is the signal that was time compressed to remove alternate pitch periods, which removes some of the acoustic information. The bottom signal has the time restored, but with the pitch periods still removed.
Results.
If we look at speech recognition as a function of increasing distortion, in this case the WDRC parameters that changed were both release time and compression ratio, we find that there is no difference between the two age groups (Figure 7). As distortion increases we see a small but significant reduction in speech recognition.
Figure 7. Results of speech recognition as a function of increased distortion for both Young-Old and Old-Old groups.
For the more difficult listening condition, where we have taken out some redundant cues of the speech signal, there was still no age effect. Both the Young-Old and Old-Old groups performed about the same. Both groups were equally affected by the removal of information and there was a greater effect of distortion when the redundant cues were not available as back up.
Figure 8 shows an acoustic example of the stimuli in this study, using the word 'strap'. In the panel on the left of Figure 8, the word 'strap' is unprocessed. Note the /t/ and /p/ sounds. In the right hand panel we have the example of the signal with reduced redundancy and also processed with compression, and there are two things to note. First, the silent gap for the stop consonant /t/ has been filled in with some noise. Second, the release burst of the /p/ has been enhanced by processing. Filling in the silent gap could be potentially negative for recognition, while enhancing the burst could potentially be beneficial.
Figure 8. Spectrogram of the word "strap" - unprocessed in the left panel; with reduced redundancy and processed with compression in the right panel.
We analyzed common errors for these listeners. One common error we found was a substitution of /s/ for the entire /str/ cluster at the beginning of the word. So instead of hearing 'strap' listeners heard 'sap'. In this case, the stop completely disappeared when the silent gap was filled in with some noise just due to processing. Another common error was to substitute a different stop consonant for the final /p/ sound, or to omit it altogether. So when the release burst for /p/ was enhanced through processing, often listeners still did hear a stop consonant but instead of the /p/ they may have heard /t/ or /k/. One reason for that is the amplitude of the release burst could signal the identity of the stop consonant, so listeners were starting to get confused about which stop consonant they heard.
Implications for Hearing Aid Processing
With regard to hearing aid signal processing, the main acoustic change of WDRC processing is seen for fast-acting (syllabic) compression, with the main effects on the amplitude cues of speech.
The "release time debate".
In terms of hearing aid setting, we saw from the behavioral results that we can use compression to change the amplitude cues of speech to restore audibility and the nonlinearity that is lost due to the hearing loss, but there are limitations on how much envelope change is tolerable. Within the sample tested here, that tolerable alteration wasn't dependent on age.
Most of you are probably aware of the debate regarding the setting of wide dynamic range compression release time, particularly in relation to the cognitive function of older adults. It is interesting because some researchers have found that for older adults who have decreased cognition, they might do better with a faster release time (Cox & Xu, 2010). Other researchers, however, have shown that older adults with decreased cognition do better with a slower release time (e.g., Gatehouse, Naylor & Eberling, 2006, Lunner & Sundewall-Thoren, 2007).
We may be left wondering how to proceed and we don't have a straightforward answer yet. Some of the differences that can affect whether someone will benefit from a fast or slower release time seem to be related to how cognition is measured and also on the type of speech materials that are used. So, for example, if the speech is high context then listeners with higher cognition can take advantage of using top down processing, whereas older adults with lower cognition might need the extra audibility provided by a fast release time. However, the jury is still out on this issue related to setting of release time and how that ties in with the cognitive changes of older adults.
Other hearing aid features.
Earlier we highlighted the fact that older adults might have more difficulties in complex listening situations and we know that directional microphones can improve the signal to noise ratio (SNR) in many complex listening situations. However, success with directional microphones depends on their proper use, i.e. whether someone is able to switch into directional microphone mode if it is not automatic and also being able to position themselves so that the signal is in front and the noise is behind or to the side. Real world benefit with directional microphones therefore might be slightly less than you would expect in laboratory conditions, depending on how someone can handle the technology.
Another technology that can be useful in complex listening situations would be an FM system. This is a technology that can improve the SNR, as again, noisy situations are ones where older adults might have more difficulties than younger listeners. Successful use of FM is also going to depend on the user's ability to handle all of the different components.
Finally, I want to mention unilateral versus bilateral fittings and in general just highlight that while two ears are almost always better than one, there are exceptions. About 10% of older adults will perform poorer with two hearing aids as they will have some binaural interference (Holmes, 2003) and therefore 10% of adults will do better with one hearing aid rather than two.
General Principles for Fitting Hearing Aids to Older Adults
1. Restore audibility.
First and foremost, choose processing that's going to restore audibility to compensate for hearing loss. This should be done in a way that is minimally disruptive to the speech signal, with very little distortion.
2. Improve the signal-to-noise ratio.
Secondly, provide any technology that can help improve the SNR. This is important for all listeners with hearing loss but seems to be even more important for older listeners.
3. Consider individual variability in handling ability, cognition and binaural interference.
Finally, for older adults, we need to consider individual variability in a few areas such as their ability to handle the technology. We also need to consider differences in cognition although we're still not quite sure how to measure those differences and how they play out in terms of choosing processing. We also need to consider that there might be some individual differences in binaural interference such that not all older adults will benefit from two hearing aids, however the majority will.
Before we move into our next topic, I want to see if there are any questions on the material I've covered thus far.
Question: What are the slow versus fast release times in the examples that we heard?
The slow release time is 800 milliseconds and fast release time was 12 milliseconds.
Question: For the first gap duration task, how old are the older adults and the younger adults?
That was a compilation of results from several different studies so I can't give one particular answer but that's a great question.
Barriers and Facilitators to Hearing Aid Uptake
We've gone into great detail looking at acoustic measures, temporal processing, and speech recognition, and now I want to look at the big picture. Optimizing the hearing aid processing isn't going to make a difference at all if older adults are reluctant to even buy hearing aids in the first place. Although this is a bit of a topic switch it is highly relevant.
Let's examine whether older adults are actually getting hearing aids and what might be stopping them if they choose not to get them. I think we are all familiar with hearing aid usage statistics. The statistics consistently show that 20% of those that could benefit from hearing aids are actually getting them. This means that 80% of those who need hearing aids are not even purchasing them. We're very interested in determining why that is and seeing if we can close that gap.
The Hearing Healthcare Pathway
There are several stages along the way in someone's hearing health journey, according to Knudsen and colleagues (2010). The first step is help-seeking. Someone might start out thinking, "Maybe I have a hearing loss and I should start to get help for it." Once they get help, i.e. they see an audiologist and have a hearing test, if a hearing aid is recommended, the next stage is hearing aid uptake. Hearing aid uptake depends on whether they actually follow through on the recommendation and get the hearing aid or not. Once they have bought the hearing aid, the next stage is hearing aid use; whether they actually use the hearing aid or whether it sits in the drawer. The final stage is satisfaction. Satisfaction is our ultimate goal for someone who moves through the pathway, buys a hearing aid, and uses a hearing aid.
Hearing Aid Uptake.
What I'm going to focus on now is just the stage of hearing aid uptake, specifically, if someone has had a hearing aid recommended, whether or not they actually purchase a hearing aid and what might be stopping them from moving to that phase. In order to start looking at this question we recently reviewed the literature to see what other people have found in terms of barriers or facilitators to hearing aid uptake (Jenstad & Moon, 2011). In looking across the literature, we found five main factors that determined whether or not someone would get a hearing aid: Self-reported hearing loss, stigma, degree of hearing loss, personality or psychological factors, and cost of hearing aids.
These were all researcher driven factors in the sense that the researchers decided which subset of factors to even measure and quantify. I'm going to discuss each one in a little more detail.
Self reported hearing loss.
If hearing loss was not perceived as significant enough to affect activity limitation or participation restriction then hearing aid purchase was very unlikely. Related to that is whether the individuals believe that future hearing aid use could even affect their quality of life (Helvik, Wennberg, Jacobsen, & Hallberg, 2008; Meister, Walger, Brehmer, von Wedel, U., & von Wedel, H., 2008). So someone could feel very affected in terms of their hearing loss but if they didn't believe that hearing aids could make a difference then hearing aid purchase was unlikely.
Stigma.
Stigma is interesting because it was commonly studied but it didn't come up as a strong predictor or consistent predictor of hearing aid uptake (Franks & Beckmann, 1985; Garstecki & Erler, 1998). I found that interesting because stigma is something that we tend to think about when we consider why people aren't getting hearing aids. I'm curious whether this is something that might have changed for the better over time. Perhaps some of the advertising that we have been doing, or public education and awareness about hearing loss and hearing aids, has actually reduced the stigma over time. We've seen a lot of developments in hearing aid technology and an increased cosmetic appeal, as well as increased public attention to hearing loss and hearing aids, and it would be a great if these things did indeed reduce the stigma related to hearing aids.
Degree of hearing loss.
Independent of self perceived hearing loss, degree of hearing loss was predictive of hearing aid uptake (Garstecki & Erler, 1998). As you might expect, the worse one's hearing thresholds, the greater the likelihood of hearing aid purchase and use.
Personality and psychological factors.
In terms of personality and psychological factors, some interesting trends can be seen (Cox, Alexander, & Gray, 2005; Garstecki & Erler, 1998; Helvik et al., 2008). People who are more open to new things might be more successful trying strategies other than hearing aids. For example, they might be willing to try communication strategies, or environmental modifications to help them hear, such as setting up the room differently. In other words, someone who is more open might be less likely to purchase a hearing aid. People who are higher in neuroticism might be more affected by the stigma associated with hearing loss and hearing aids and less likely to purchase hearing aids. People who have a strong internal locus of control are more likely to buy hearing aids than those who have a less internal locus of control. Finally, related to personality and psychological factors are coping strategies. People who don't report using maladaptive behaviors in terms of their listening and communication strategies are likely to reject hearing aids. One reason for that might be, if they are reporting not using maladaptive strategies perhaps they are in fact using good strategies that are working to help them overcome their hearing loss for now. Alternately, maybe they're in denial and not realizing that they're using maladaptive strategies.
Cost of hearing aids.
Like stigma, I expected cost of hearing aids to be a greater barrier to uptake than was actually found in the literature (Franks & Beckmann, 1985; Garstecki & Erler, 1998). Some of the studies we looked at did report that cost of hearing aids was a barrier for some people, but it didn't seem to be as strong a predictor as self perceived hearing loss, for example. There were also some distinctions about what is meant by cost of hearing aids. In some instances, participants meant that if cost of hearing aids was a barrier it meant that they couldn't afford hearing aids. In other instances when people said hearing aids cost too much, it meant that they thought that hearing aids were not worth the cost. For these people, they were considering the cost-benefit analysis and deciding that hearing aids would not be worth the cost.
Barriers and Facilitators to Hearing Aid Uptake - Qualitative Study
Methods and procedures.
To follow up on what we found in the literature, we were interested in seeing what clients themselves had to say about their reasons for getting or not getting hearing aids. The five factors that I just discussed came from what I'm referring to as researcher driven studies or researcher driven paradigms. We were interested in knowing from clients themselves what are their stories, what led them to the point of deciding that they were going to get or not get hearing aids? One of my recent graduate students, Danielle Winsor, did a study using qualitative methods to identify barriers and facilitators to hearing aid uptake as reported by females with age-related hearing loss (Winsor, 2011). The collaborators on this study were Joanie Sims-Gould, Social Worker, and Barbara Purves, Speech-Language Pathologist.
We studied only females because there are some gender differences in terms of the barriers and facilitators to hearing aid uptake so we wanted to look at just a single homogenous group of participants.
Participants were 60 to 75 years of age and all had age related hearing loss. They had all recently been told that they would benefit from amplification. There were nine participants; five had decided to get hearing aids while four had decided to not get hearing aids or to put off making the decision. We compared those two groups in terms of their stories and what led them to that point of getting hearing aids.
Each of these women participated in about an hour-long interview where we just simply asked them, tell us about your experience of deciding whether or not to get a hearing aid.
Results.
Perhaps not surprising to audiologists, the overriding theme was that there is a complex interaction of factors that influence the decision regarding hearing aid uptake. It was not straightforward. It was never just a self perceived hearing loss or the cost of hearing aids; there were a lot of different factors that went into the decision.
Borrowing from sociology terminology, we call this complex interaction "dynamism" which is shorthand for the dynamic interplay of the factors. There were four themes that emerged from the women's stories about why they decided to get or not get hearing aids. There is a lot that we can learn from these themes.
First of these themes is self perceived hearing. This is what we talked about before in terms of the researcher-driven data. As the name suggests, this refers to how the individual perceived her own hearing - how she noticed her hearing loss, how it affected her and how she dealt with it. For the most part, if they noticed having difficulties in conversation with others, that acted as a facilitator towards getting hearing aids. If the woman noticed that she was using communication strategies and using them effectively, then that was a deterrent to getting hearing aids because she would go ahead with using her communication strategies rather than seeking other help. But once she got to the point where she realized that she could no longer use communication strategies, that was often a decision point that led to needing to get hearing aids. Some of the women were very clear about recognizing the psychosocial impact of their hearing loss. Some of them clearly articulated that they noticed they were getting lonely, isolated and depressed because of their hearing loss and this was a factor in deciding to get hearing aids.
The second of the four themes that emerged was information gathering and informed decision making. These women were all very interested in getting a lot of information about hearing aids, where to go for hearing aids, and what clinics to go to. They put pressure on themselves in terms of deciding what would be the best hearing aid for them. A lot of them talked about not being sure where to go to get information about hearing aids and having some suspicions about the source of the information. They also talked about different types of information that they wanted including clinics to go to, financial information, available options and how to choose hearing aids. They all talked about expectations for hearing aids, and their fears about hearing aids, some of which were based on lack of information or misinformation. They also talked about expected improvements in quality of life and their hopes to be able to hear what they had previously missed. They also talked about fears about adapting to hearing aids and that served as a barrier for many of the women.
The third theme is the influence of others which I'll talk about in a moment.
The fourth theme that came up was cost. It was talked about by all the women but it wasn't as much of a barrier as might be expected. Most of the women were doing a constant cost-benefit analysis. It was always the question of whether the hearing aids were worth the cost; it was not that the cost of hearing aids was too much.
For at least one woman, finances were a facilitator because she was about to retire from work and lose her benefits, so she was in a hurry to get hearing aids while she still had benefits.
Lastly, I want to talk a bit more about the third theme, influence of others. Under this general theme, the first sub-theme that came up was the influence of family and close friends, which may not surprise us. There are a number of ways in which family influenced the women - sometimes in a positive way and sometimes negatively.
Here is a quote from one woman I'll call Judith:
"My son has been bugging me for years, but he's just really a sarcastic bug, so I sort of negated anything that he said."She ignored her son's nagging because she felt he had been nagging her for years about her hearing loss, so that was not a facilitator for her. For other women, the influence of family and close friends was very important in terms of thinking about their responsibility to others. For example, here is a quote from another woman, Carol:
"I thought, you know, I have maybe a responsibility for myself as well as the people that are around me not to be, you know, for them to constantly have to say, 'I'm tired of saying it over and over again."The influence of the audiologist or another Hearing Healthcare Professional was another definite sub-theme. The words that the professional said had a big impact for these women. Here is what some of the women had to say:
"When I first had my testing done at [the hospital], the audiologist there told me, she said, 'well, you're kind of borderline, you might benefit from it but,' she said, 'if you go to a place that dispenses hearing aids,' she said, 'they're going to want to sell you a hearing aid, so bear that in mind.' So I just, I didn't do anything at that point."- Patricia
"For a real good professional, it's somebody that yes, education is very important, but so are a lot of other things. In terms of behaviour and values and you know, commitment, compassion, understanding." - Carol
"I think it was mainly trust." - JudithPatricia in particular talks about how, after her hearing test, the audiologist said that if she went to a place that dispenses hearing aids, they're going to want to sell you a hearing aid. That statement was a barrier as it stopped her from doing anything further about getting hearing aids for quite a while.
In terms of influence of others, the women also talked about seeing people with hearing loss and whether those people coped well or not with a hearing aid:
"I have another friend that I play golf with and she doesn't wear her aids and I realize now how tiring it is for someone. I would tell her something and then she was constantly saying, 'what did you say? what did you say?' It's just really tiring."
- CarolThe other people with hearing loss often served as either a model or a bad example that influenced hearing aid uptake either positively or negatively.
Are these factors modifiable?
I'm really interested in whether we can modify any of those factors. There are some things we cannot change but there are definitely some places where we can step in and try and remove some of the barriers.
Two areas that we may be able to potentially influence are information gathering and the hearing aid process. Regarding information gathering, we can provide information from unbiased sources about technology and hearing aid options. Regarding the process, we know it can be emotional, and there are often other medical needs in older adults. If there is anything we can do to help make the process less overwhelming, particularly in regards to assisting with figuring out where to go for testing, what hearing aids to choose, and how to find funding, we may be able to help facilitate hearing aid uptake.
There is some interesting new research (Yueh, et al., 2010) looking at whether we can use universal adult hearing screening as a way to improve hearing aid uptake and use. Early indications show that there might be a small but significant effect of screening so it is definitely worthwhile considering that in the future.
Summary
We've looked at some changes with age related hearing loss. Changes in audibility are the same for both older and younger listeners with hearing loss. Older listeners have some particular problems with temporal processing and complex speech recognition. The implications for amplification are to choose processing that provides audibility, doesn't distort the signal, improves the signal to noise ratio, and is easy to use and handle. Finally, we talked about some considerations for why older adults might be reluctant to get hearing aids and some way that we might be able to encourage hearing aid uptake.
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