Research Request – Guidance for prescribing premium versus basic level hearing aids

DOCUMENT 2

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Research Request – Guidance for prescribing premium versus basic level hearing aids

Brief	1. What constitutes a ‘good functional’ outcome for speech discrimination ability (% score) in background noise? 2. What is a ‘good’ signal-to-noise (SNR) ratio for hearing impaired people wearing hearing aids? Compared to people with normal hearing? 3. What constitutes a ‘significant improvement’ in speech discrimination score (%)? As the participant tries higher levels of hearing aids.
Date	30/10/20
Requester	Leeanne redacted: s22(1)(a)(ii) - irrelevant (Senior Technical Advisor TAB) Jane redacted: s22(1)(a)(ii) - irrelevant Assistant Director TAB)
Researcher	Jane redacted: s22(1)(a)(ii) - irrelevant (Research Team Leader TAB)
Cleared by	Jane redacted: s22(1)(a)(ii) - irrelevant (Research Team Leader TAB)

Contents

What constitutes a ‘good functional’ outcome for speech discrimination ability (% score) in background noise? …………………………………………………………………………………………………………………. 2 Summary …………………………………………………………………………………………………………………………… 2 Maximum word recognition scores for those with hearing loss in quiet ……………………………………….. 7 What is a ‘good’ signal-to-noise (SNR) ratio for hearing impaired people wearing hearing aids? Compared to people with normal hearing?……………………………………………………………………………….. 9 Summary …………………………………………………………………………………………………………………………… 9 What constitutes a ‘significant improvement’ in speech discrimination score (%)? As the participant tries higher levels of hearing aids. ………………………………………………………………………………………….. 12 Summary …………………………………………………………………………………………………………………………. 12 Percentage word recognition improvement with increases in signal-to-noise ratio ………………….. 15 Independent research on basic versus premium hearing aids ……………………………………………………. 16 Hearing impairment and dementia ………………………………………………………………………………………… 23 References ………………………………………………………………………………………………………………………….. 25

Please note: The research and literature reviews collated by our TAB Research Team are not to be shared external to the Branch. These are for internal TAB use only and are intended to assist our advisors with their reasonable and necessary decision making.

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Delegates have access to a wide variety of comprehensive guidance material. If Delegates require further information on access or planning matters they are to call the TAPS line for advice. The Research Team are unable to ensure that the information listed below provides an accurate & up-to-date snapshot of these matters

What constitutes a ‘good functional’ outcome for speech discrimination ability (% score) in background noise?

Summary

• There are not scientifically grounded guidelines for what constitutes are ‘good functional’ outcome for speech discrimination scores in background noise
  • Significant variation between scores exists even in those with similar pure tone thresholds
  • Studies utilise different testing environments and present sounds at different thresholds making comparisons difficult
  • Various studies have shown that on average, normal listeners perform 20% better in noise than those with mild-moderate hearing loss
    • A single study by Dimitrijevic (2004) found that unaided hearing impaired listeners achieved a word discrimination score of 17% (±10) at 67 dB masking compared to normal hearing listeners who achieved 62% (±12)
  • A table provided developed by Phoenix Hearing Instruments shows that at a ‘good’ SNR of 6-12 dB hearing impaired listeners are able to achieve speech discrimination scores of 30-50%

A major limitation of performing word recognition in quiet is that it is not representative of the “real world” and therefore does not reflect the range of listening conditions hearing-impaired listeners face on a daily basis. For instance, a study that examined noise levels of restaurants found that nearly 78% had signal-to-noise ratios (SNRs) considered detrimental to speech intelligibility for hearing-impaired patrons (1). The same people who struggle in restaurants and other noisy environments often present with good or excellent word recognition scores in quiet (1). Keith and Talis (2) measured word recognition scores in 170 hearing-impaired veterans and found that approximately 60% obtained word recognition scores of 90% or better. This study and others suggest a ceiling effect exists and word recognition scores measured in quiet are simply not sensitive

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enough to the communication difficulties in background noise that occur for patients with sensorineural hearing loss (3).

It is difficult to define what constitutes a ‘good functional outcome’ for speech discrimination scores in quiet or noise. This is because substantial variation exists within individuals and among populations based on patterns of hearing loss and speech levels. A maximum speech recognition score can be achieved using a range of speech levels (4-7). Except in cases of relatively normal hearing or profound hearing loss, it is difficult to predict the maximum word recognition score for a particular individual (7). Beattie, Barr (3) present examples to illustrate how patients with similar pure tone threshold testing can have very different speech discrimination scores when tested in noise (Figure 1).

Figure 1. Word recognition functions for two participants with similar hearing losses (moderate, flat to gradually sloping audiograms) with substantially different scores, particularly for the 15 dB SNR. Puretone thresholds are shown at the top of the figure for each participant. The bold line represents mean scores for normal hearing participants.

Because of this variation it is difficult to group individuals into poor, good, excellent etc. Each individual will have different functional goals and likely experience different listening environments in their daily life. Therefore, 50% discrimination in noise may be good for one person and 70% for someone else. Figure 1 has been taken from the Phoenix Hearing Instruments website. The source of

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the data and the definition of “hearing impairment” is unknown, however it provides a basic guideline of average speech discrimination scores as SNR is increased.

Figure 1. Speech discrimination scores across varying signal to noise ratios for normal and hearing impaired patients.

Two studies by Beattie (8) and Beattie, Barr (3) compared individuals with normal hearing and those with hearing loss to show how noise impacts word recognition scores.

Beattie (8) recruited 18 normal-hearing participants (age 18-26) and 12 with mild-moderate sensorineural hearing loss (age 54-80). Lists 1-4 (Forms A and B) of the CID W-22 test (monosyllabic words) and a recording of multitasker noise (20 voices) were utilised in the experiment. The stimuli were presented at 45 and 65 dB hearing loss as these were representative of average conversational speech and very loud speech. Signal to noise ratios of 0, 6, 12, 18 and 24 dB were selected. Testing was not conduced at 45 dB hearing loss signal or at a 0 dB SNR for hearing loss participants because preliminary data had suggested these conditions would provide little useful information.

Beattie, Barr (3) recruited 51 normal-hearing women (age 18-30) with no history of otoneurologic pathologies. Each participant passed a 15 dB hearing loss screening at octave frequencies from 500 Hz to 4000 Hz. Lists 1-3 (Form A) of the CID W-22 test (monosyllabic words) and a recording of multitasker noise (20 voices) were utilised in the experiment and tested at a fixed intensity of 50 dB HL across SNRs of 5 dB, 10 dB and 15 dB. A total of 30 participants with mild-moderate hearing loss were recruited. Stimuli were presented at patient loudness discomfort level (LDL) in quiet, 10 dB and

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15 dB. Maximum word recognition scores (PB Max) ranged from 48% to 100% with a mean of 83% for hearing impaired listeners.

Table 1 and Table 2 provide the results of these two experiments for normal and hearing impaired participants.

Table 1. Normal hearing participants

Signal-to-noise-ratios
Beattie (1989) (8) Normal hearing participants
Presented at 45 dB HL
0 dB	6 dB	12 dB	18 dB	24 dB Statistic (% word recognition score)
18	56	84	93	94 Mean
10	16	9	5	5 SD
4-34	38-90	70-98	84-100	84-100 Range
0 dB	6 dB	12 dB	18 dB	24 dB Presented at 65 dB HL
13	45	79	85	94 Mean
11	18	14	10	5 SD
0-34	16-88	54-100	64-100	84-100 Range
Hearing impaired participants
	6 dB	12 dB	18 dB	24 dB Presented at 65 dB HL
	35	56	64	72 Mean
	14	13	11	13 SD
	0-58	32-80	48-84	42-90 Range

Table 2. Hearing impaired participants

Signal-to-noise-ratios
Beattie, Barr (3) Normal hearing participants
Presented at 50 dB HL

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5 dB	10 dB	15 dB
45.4	73.9	86.7 Mean
46.0	76.0	86.0 Median
6.2	5.8	5.3 SD
32-56	58-84	76-100 Range

Hearing impaired participants

Presented at LDL

Quiet	10 dB	15 dB Statistic (% word recognition score)
84.8	40.4	59.5 Mean
88.0	62.0	36.0 Median
12.8	14.0	15.0 SD
40-100	34-86	20-66 Range

Results for normal hearing participants in both experiments for monosyllables in noise can serve as a reference for what constitutes an ‘excellent’ functional outcome. Those with mild to moderate hearing loss in the study by Beattie, Barr (3) exhibited poorer word recognition scores in noise than normal hearing subjects. These result suggest that background noise which has little effect on normal hearing participants can substantially affect word recognition performance of hearing impaired listeners. This adds further weight to the argument that it is difficult to predict performance in noise using scores in quiet.

Comparison of word recognition functions for normal and hearing impaired listeners in the Beattie (8) study revealed that scores for normally hearing listeners were about 20% higher than for the hearing impaired listeners (2.6% per dB for hearing impaired and 3.6% per dB for normal listeners). Therefore, smaller increases in SNR result in greater speech discrimination scores for normal listeners. The functions also indicated that thresholds (50%) were obtained at a SNR of approximately 6 dB for normally hearing participants and a SNR of approximately 11 dB for the hearing impaired group.

Dimitrijevic, John (9) investigated the word recognition scores of 10 young normal hearing participants (mean age 28 years), 10 elderly normal hearing participants (mean age 68 years) and 10 elderly hearing impaired participants with typical sloping audiograms with the greatest loss at high

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frequencies (mean age 75 years). Word recognition scores were measured using Auditec recordings of W-22 and NU-6 word lists. Fifty words from a list were presented at 70 dB SPL through two free- field speakers. Hearing-impaired subjects were tested using their hearing aids and no masking. Results (see below) showed that hearing impaired listeners has statistically significantly (P <0.001) worse word recognition scores in quiet and in noise. Even when aided, the hearing impaired group were 20% worse. At 67 dB masking, unaided hearing impaired participants were 45% worse compared to normal hearing participants.

Table 3. Results from Dimitrijevic study.

	Quiet	67 dB Masking	70 dB Masking
Young normal-hearing	97 ± 5	62 ± 12	38 ± 18
Elderly normal-hearing	97 ± 2	43 ± 13	17 ± 9
Elderly hearing-impaired (unaided)	56 ± 30	17 ± 10	—
Elderly hearing-impaired (aided)	76 ± 18	—	—

Percentages, mean ± SD.

Maximum word recognition scores for those with hearing loss in quiet

Clinical judgements are often made regarding whether maximum word-recognition scores (PBmax) are appropriate in relation to degree of sensorineural hearing loss. In order to determine if word recognition is significantly poorer than expected, it is necessary to consider the lower boundary of PBmax associated with a particular degree of hearing loss for speech materials commonly used to measure word recognition.

In the study by Dubno, Lee (7) word recognition scores were obtained at several speech levels from 407 ears with sensorineural hearing loss of cochlear origin. Of the 407 ears, approximately 25% were under 60 years of age and 75% were greater than 60 years of age. PBmax was defined as the highest point on the score level function. Scores at all levels were assembled in 11 Puretone average groups. A computer simulation was used to find the 95% confidence limit (CL) for maximum word recognition scores for each group. PBmax values corresponding to the 95% CL are provided in Table 4 and 5 below for 25-item and 50-item NU-6 word lists. These can be used to define the PBmax upper and lower limit for different levels of hearing loss. No table could be located which provides these scores in noise.

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Table 4. 95% CL for PBmax for the 25-item NU-6 word lists	Table 5. 95% CL for PBmax for the 50-item NU-6 word lists

PTA (dB HL) a	95% CL for PB max (%) Equation	Discrete	PTA (dB HL) a	95% CL for PB max (%) Equation	Discrete
-3.3	97.6	100	-3.3	97.5	98
0.0	96.7	100	0.0	96.5	98
1.7	96.2	100	1.7	96.0	96
3.3	95.5	96	3.3	95.3	96
5.0	94.9	96	5.0	94.6	96
6.7	94.1	96	6.7	93.8	94
8.3	93.2	96	8.3	92.9	94
10.0	92.3	96	10.0	91.9	92
11.7	91.3	92	11.7	90.9	92
13.3	90.2	92	13.3	89.7	90
15.0	89.0	92	15.0	88.5	90
16.7	87.7	88	16.7	87.2	88
18.3	86.2	88	18.3	85.7	86
20.0	84.7	88	20.0	84.2	86
21.7	83.1	84	21.7	82.6	84
23.3	81.4	84	23.3	80.9	82
25.0	79.6	80	25.0	79.2	80
26.7	77.7	80	26.7	77.3	78
28.3	75.8	76	28.3	75.4	76
30.0	73.7	76	30.0	73.4	74
31.7	71.6	72	31.7	71.4	72
33.3	69.5	72	33.3	69.3	70
35.0	67.3	68	35.0	67.2	68
36.7	65.0	68	36.7	65.0	66
38.3	62.7	64	38.3	62.8	64
40.0	60.4	64	40.0	60.6	62
41.7	58.1	60	41.7	58.4	60
43.3	55.8	56	43.3	56.2	58
45.0	53.5	56	45.0	54.1	56
46.7	51.3	52	46.7	51.9	52
48.3	49.0	52	48.3	49.8	50
50.0	46.8	48	50.0	47.7	48
51.7	44.7	48	51.7	45.7	46
53.3	42.6	44	53.3	43.7	44
55.0	40.5	44	55.0	41.7	42
56.7	38.5	40	56.7	39.8	40
58.3	36.7	40	58.3	38.0	38
60.0	34.8	36	60.0	36.2	38
61.7	33.0	36	61.7	34.5	36
63.3	31.3	32	63.3	32.8	34
65.0	29.6	32	65.0	31.2	32
66.7	28.1	32	66.7	29.7	30
68.3	26.6	28	68.3	28.3	30
70.0	25.2	28	70.0	26.9	28
71.7	23.8	24	71.7	25.5	26

aPTA (dB HL) is the average pure-tone threshold at 0.5, 1.0, and 2.0 kHz. | aPTA (dB HL) is the average pure-tone threshold at 0.5, 1.0, and 2.0 kHz. |

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What is a ‘good’ signal-to-noise (SNR) ratio for hearing impaired people wearing hearing aids? Compared to people with normal hearing?

Summary

• No normative data exists for what is considered a poor, good or excellent (etc.) SNR for hearing impaired people both unaided and aided. A general trend is that SNR loss increases with hearing loss
• SNR loss varies significantly between individuals and cannot be predicted based on pure tone average results
• Normal hearing people on average require +2 dB SNR to correctly repeat 50% of the key words
• Guidelines for interpreting SNR loss are:
  • Normal 0-2dB SNR loss
  • Mild 3-6dB SNR Loss
  • Moderate 7-12dB SNR Loss
  • Severe >12dB SNR loss
• Studies have shown that hearing aids that incorporate directionality can improve the SNR by approximately 3 to 8.5 dB
  • Several studies have identified that a difference of at least 3 dB is required to detect a ‘just noticeable difference’ in real world settings

Difficulty hearing in noise can be quantified by measuring a listener’s signal-to-noise ratio (SNR) loss (10, 11). SNR loss is the increase in SNR (in dB) required by someone with a hearing loss to understand speech in noise, relative to the average SNR required for listeners with normal hearing (10). On average, people prefer a 10 dB SNR for listening, regardless of age or hearing status (12).

There are various tests which measure SNR loss: the Speech-In-Noise test (SIN) or Quick SIN are the most commonly used and cited in the literature (13, 14). The SNR loss score represents the SNR which a listener with hearing loss requires above the SNR which a normally hearing listener requires to achieve 50% correct sentence identification; this is called the SNR-50 (10, 11, 15, 16). Normally hearing people on average require +2 dB SNR, i.e. target talker 2 dB louder than background babble talkers, to correctly repeat 50% of the key words on the QuickSIN test (15, 16). As an example, a

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hearing-impaired person who requires the target speech to be 12 dB higher than the noise to achieve a 50% correct score would have a 10 dB SNR loss.

Some guidelines have been provided for interpreting performance on the QuickSIN test based on adjectives that describe the amount of SNR loss (17):

Normal 0-2dB SNR loss

Mild 3-6dB SNR Loss

Moderate 7-12dB SNR Loss

Severe >12dB SNR loss

These categories of SNR loss (normal, mild, etc.) and their associated recommendations are only suggestions. There is no formally recognised scale of SNR loss categories or appropriate intervention (17).

There are large individual differences among hearing-impaired listeners on measures of SNR loss. A general trend is that SNR loss increases with hearing loss, but the variance is quite large and can range from no loss (normal-hearing performance in noise) to greater than 20 dB of SNR loss (10).

Predicting a listener’s SNR-50 from hearing thresholds can be difficult. In Figure 2, high variability among listeners with similar hearing thresholds can be seen (17). For example, people with an average hearing threshold (pure tone average of 500, 1000, and 2000 Hz) of 40 dB HL may only need a SNR of -3 dB to perceive 50% of speech, while others need +6 dB SNR. This range suggests that some people have greater or worse abilities to cope with competing noise, even with similar hearing threshold levels (18).

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Figure 2. The relationship between pure tone average hearing thresholds and a listeners SNR-50. Predicting how a person performs in background noise can be difficult, due to the variability observed between people with the same pure tone average.

Several studies have supported the effect of aging on perceptual abilities. A comparison of these influences in older and younger people revealed that older people required a 3–4 dB higher SNR than younger people to have the same proper perception under similar noise conditions. It appears that age-related changes in auditory–cognitive system functions are responsible for the requirement of an enhanced SNR in the elderly (19-21).

There have been several studies which investigate SNR improvement through the use of hearing aids. Those that incorporate directionality can improve the SNR approximately 3 to 8.5 dB (22, 23), but this is dependent on factors such as the distance and spatial location of the noise in relation to the speech signal, the type and number of noise sources, and the amount of reverberation in the environment (24).

• Walden and colleagues (25) found that directional microphones in hearing aids are most effective when the signal of interest is in front of the listener, within 10 feet, and the background noise is spatially separated from the signal of interest location. These conditions limit directional benefit, but the provided improvement in SNR can help those with SNR losses ranging from 4 to 8 dB in many environments.
  • For those with greater SNR losses, a directional-microphone hearing aid can still provide the benefits of listening comfort and can help with understanding of speech in noise as long as contextual and speech cues are available (10). Listeners with SNR losses greater than 8 or 10 dB will need additional help to understand in noise, such as visual cues (10).
• A pilot study by Beck & Benite (26) showed that using different hearing aid parameters change the level of SNR improvement. For example, an average of 4 dB improvement was seen when noise reduction settings were not set to maximum. When testing using the maximum noise reduction an average of 6 dB SNR improvement was seen.

The ability to detect changes in SNR has been investigated in two separate studies.

• A report into what constitutes a meaningful or ‘just-noticeable-difference’ in SNR found that a 3 dB difference was required independent of hearing ability. These results suggest that noise reduction technologies may need to achieve a benefit greater than 3 dB to be reliably discriminable (24).
• A study of 16 hearing-aid wearers made paired comparisons between different SNRs, using values from 6 dB to þ6 dB in 2 dB steps. The results showed that subjects performed at

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chance level with a 2-dB difference but achieved about 90% correct with a 4-dB difference and 100% for both a 6-dB and an 8-dB difference. The authors concluded that while a 2-dB change in SNR could bring benefit, such benefit was unlikely to be noticed in a real-world setting (27).

What constitutes a ‘significant improvement’ in speech discrimination score (%)? As the participant tries higher levels of hearing aids.

Summary

• There is no consensus in the literature as to what constitutes a ‘significant improvement’
  • Most commonly a difference of 8% has been suggested (2% has been noted as not being clinically relevant) however it is highly likely that differences of 8% may occur by chance, especially if small word lists are used (50 or less).
  • Few papers compared different device types and used speech discrimination scores/word recognitions scores as an outcome measure. Findings suggest that:
    • Depending on the devices being compared, there was a wide range of improvements seen (ranging from 4.3% and 40%)
    • Homogenous devices rarely produce significant differences
    • Level of hearing loss and the type of noise delivered impacts improvements
• Peer reviewed literature from product manufactures comparing devices is sparse (publish product brochures and ‘white papers’) – product brochures always sell the benefits of top of the range products
• Studies tend to group patients together as “mild to moderate’ hearing loss and participants
• with severe or proud loss are rarely included
• A 1 dB improvement in SNR is said to equate to a 10% improvement in word recognition score

Carhart (28) is often credited with recommending that the hearing aid corresponding to the highest speech discrimination score in noise should be chosen, but he also stated that in most cases patients will obtain excellent scores with each of several hearing aids. He suggested, however, that a score difference of 8% was sufficient to indicate selecting the hearing aid that yielded the superior score. Berger (29) also recommended that a speech discrimination score of 8% or less, obtained in quiet

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with commonly used word lists, should not be considered significant. In contrast, Walden, Holum- Hardegen (30) considered a difference of approximately 6% between aided discrimination scores be taken to represent a significant performance difference. However, these methods are only arbitrary and have not received experimental validation in terms of benefit or satisfaction (31).

A further consideration is the reliability of speech discrimination and word recognitions scores. The score of one of two hearing aids will exceed the other nearly 30% of the time purely by chance for scores in the 30-70% range, using 25 word lists (31). Even with 50 word lists, an 8% difference would occur by chance 21% of the time between equally performing hearing aids (31). In order to identify a difference between two conditions (ears, hearing aids, individuals) of 8%, and assuming an error rate of 5% and word recognition scores in the 20%-80% range, approximately 200 test items must be presented in each of the two conditions (8). More test items must be used if the 5% error rate is judged too high or if the clinician wants to identify true differences of less than 8%. Conversely, fewer items may be used if clinicians are willing to tolerate more errors and/or if they are willing to identify true differences that exceed 8%.

The traditional method of hearing aid selection developed by Carhart (28) evaluates patient performance with selected hearing aids in three ways.

1. Spondee words are used to measure the acoustic gain of the hearing aid
2. Phonetically balanced (PB) words are used to measure the patient’s ability to understand aided speech at conversational loudness in an optimum (quiet) listening condition
3. Competing noise is added to the PB words in order to ‘stress’ the hearing aid.

The hearing aid that gives the best scores is then recommended. A common limitation of this approach is the inability to delineate differences among hearing aids due to only single words being used (32). Jerger and Hayes (32) proposed an alternative method of hearing aid evaluation using synthetic sentences and speech competition in varying degrees of difficulty. The method uses five potential test conditions from “very easy” to “very difficult” within “life like listening conditions” to enable greater capacity to determine differences in hearing aids. The authors presented six case studies (all with at least mild to moderate hearing loss) to illustrate their new testing method. In some conditions, improvement of 40% was seen between hearing aids.

Unfortunately, the authors don’t provide a recommendations for what level of improvement would constitute a change in hearing aid technology/level. Instead, they suggest that improvements in the ‘very easy’ and ‘easy’ listening conditions are sufficient for recommending a hearing aid in those with more severe hearing impairments. In contrast, patients with minimal hearing loss might not be

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recommended a hearing aid unless improvements are seen in the difficult or very difficult listening conditions.

In a study by Beck (33), a sample of 25 participants with mild to moderate symmetric hearing loss underwent listening tasks in what is described as a “lab based, yet realistic, background noise situation”. Three hearing aids from different manufactures were compared. These included one with ‘directionality’, ‘narrow directionality’, and an ‘open sound navigator’ (Opticon). Speech babble and background noise were delivered at 75 dB sound pressure loudness (SPL). The German-language Oldenburg sentence test (OLSA) was delivered to each participant while wearing each of the hearing aids. The speech stimuli loudness varied to determine the 50% SRT using a standard adaptive protocol. Each participant was seated centrally while three talkers were located in front of, as well as ±60 degrees (left and right) of the listener. Target speech was randomly presented from one of the three talker locations. Listeners were free to turn their heads as desired. Results showed that for the central speaker, word recognition scores were 20% greater for narrow directionality and open sound navigator hearing aids compared to directionality alone. For the left and right speaker there were no word recognition score differences between the directionality and narrow directionality hearing aids, however, the open sound navigator hearing aid achieved 15% higher word recognition scores. Overall scores showed that WRS were 18% greater for open sound navigator compared to the directionality hearing aid and 11% greater than the narrow directionality hearing aid.

A study conducted by Walden, Holum-Hardegen (30) randomly assigned participants with high frequency sensorineural hearing impairments into one of two parallel experiments. Experiment 1 used three electro-acoustically similar instruments while Experiment 2 involved dissimilar ones. 100- item word lists were administered in the presence of multi-tasker speech babble. The primary speech signal was presented at 50 dB HL at a zero degree azimuth, and the competing babble was delivered at a 0 dB primary-to-secondary ratio from a loudspeaker located at 180 degrees. Average inter-aid differences for the aids that were electro-acoustically similar was 4.3% (SD ±4%). The average inter-aid difference between electro-acoustically dissimilar hearing aids was 14.2% (SD ±11.8%). This data suggests that when instruments are relatively homogenous, significant performance differences on hearing aid evaluation often will not occur. In contrast, when the hearing aids are very different electro-acoustically, significant inter-aid differences may occur frequently.

A study by Shanks, Wilson (34) compared three hearing aid circuits (peak clip, compression limiting and wide dynamic range compression. Participants were divided into <40 dB and >40 dB hearing loss. All three hearing aids circuits provided benefit over the unaided condition in both quiet and

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noise. The greatest benefit was measured for soft speech in the more severe hearing loss groups. Although small statistical advantages were found for the wide dynamic range compression for the word recognition test, the differences were ~2% and are not considered clinically relevant.

Percentage word recognition improvement with increases in signal-to-noise ratio

It is generally accepted in the literature that for each decibel of SNR improvement (when presented in noise), there is an increase in word recognition ability of approximately 10% (33, 35). Similar to suggestions made by Jerger and Hayes (32), this improvement can vary due to patient characteristics and the type of noise presented. Figure 3 below shows a ‘typical’ performance-intensity (PI) function showing changes in word recognition score (%) as a function of SNR (dB). The middle region is where the slope is the steepest with potentially the greatest word recognition score improvement for a given increase in SNR. A 10% improvement can only be obtained when one is in the middle of the PI function, and depending on the nature of the noise and the speech stimulus used. It is true that, with single-syllable words when measured in the centre of the PI function, the slope is on the order of 10%/dB. But if improvements are measured in more adverse listening situations, the improvement may be negligible (35).

Figure 3. Typical performance-intensity (PI) function showing changes in word recognition score (%) as a function of SNR (dB).

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Independent research on basic versus premium hearing aids

Practitioners do not have any scientifically grounded guidelines to help them determine when to recommend basic-feature technology and when to recommend premium features. Because independent research is lacking, practitioners rely mostly on unverified manufacturer claims about feature benefits when they decide which hearing aid(s) to recommend to patients (36).

A survey of hearing care professionals has shown that hearing aid technology levels are recommended based on their perception of the patient’s activity level in life, the level of hearing aid usage for experienced users, their age, and their speech discrimination score (36). Surprisingly, the patient’s lifestyle as perceived by the hearing care professional, followed by speech discrimination, were the strongest factors in explaining treatment recommendation (36). An active patient with poor speech discrimination had a 17% chance of being recommended the highest technology level hearing aid. For a very active patient with good speech discrimination, the probability increased to 68%. Discrepancies in hearing aid technology level recommendations are not justified by academic research or evidence of optimal patient outcome with a different hearing aid technology level (36).

Given the advanced capabilities, it might be presumed that premium-feature hearing aids would outperform basic feature hearing aids in terms of sound localization. However, there is limited independent evidence to support this notion, and what evidence there is tends to have been conducted in laboratory conditions with other features disabled. Therefore, it is of considerable interest and importance to compare localization outcomes with premium-feature hearing aids to those with basic-feature hearing aids when both types of models are used as they are in daily life, with all sound processing features simultaneously active (37, 38). In the long run, it is the performance in daily living in the circumstances of the particular listener that determines the usefulness of a hearing aid fitting. Only the subjective observations of the hearing-impaired listener can provide this type of outcome data. It is reasonable to assert that the patient’s perspective is the gold standard for determining whether one type of hearing aid is better than another for that patient in the particular circumstances of his/her world (37).

This lack of independent research which investigates whether more advanced technologies provide further improvement to outcomes in selected listening situations means that hearing aid practitioners often rely on manufacturer-produced data and marketing to make recommendations about the level of technology most appropriate for a given client (39). An example is the marketing

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material provided by Bernafon for the Zerena device (premium). This device was compared to the basic level hearing aid called the Juna using 30 participants with a pure tone weighted average of 45.6 dB. Results from the unpublished/non-peer reviewed assessment showed that compared to unaided results, there was an overall improvement of Speech Reception Threshold (SRT) of 3.3 dB (p <0.001) for the Zerena device. The results also showed a significant difference between the Zerena and the Juna hearing aids (mean difference 1.4 dB, p <0.001). Whilst this is a “statistically significant” difference, it has been proposed that the just-noticeable difference of SNR measured in well- controlled listening conditions in the laboratory is 3 dB indicating that this difference of 1.4 dB would not deliver a noticeable difference to a patient in the real world (24).

Table 6 below provides the outcomes (subjective and objective) of several independent studies investigating the differences between basic and premium levels hearing aids. The overall consensus is that;

• Laboratory data showed that, overall, the premium-feature hearing aids yielded more accurate localization, reduced listening effort and greater speech understanding than the basic-feature hearing aids
• Self-reports from everyday life and quality of life measures revealed no differences between basic and premium levels hearing aids
  • The vast majority of participants could not differentiate between basic and premium
• The benefit of premium features might not be large enough to be noticed in the real world

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Table 6. Independent research comparing basic to premium level hearing aids

Author (year)	Study aim/objective	Methods/participant characteristics/outcome measures	Outcome/summary	Quality of included evidence +/- conclusion (High/Medium/Low/Very Low)
Basic Vs Premium hearing aid features
Johnson et al. (2017) (38)	To explore the difference between premium-feature and basic-feature hearing aids in horizontal sound localisation in both laboratory and daily life environments.	Single-blinded double crossover trial 4 types of hearing aids (2x basic feature and 2x premium) from 2 manufacturers) 45 Older adults (mean age 70.3 years) with mild to moderate sensorineural hearing loss Each pair of hearing aids worn for 4 weeks and fitted used best practice guidelines Outcome measures Laboratory localisation test: conducted in a sound-treated room with a 360°, 24-loudspeaker array. Test stimuli were high frequency and low frequency filtered short sentences. Both tested in noise and quiet. Speech Spatial, Qualities of Hearing Scale Questionnaire (to test daily environments)	Laboratory data showed that unaided localization was not significantly different from aided localization when all hearing aids were combined. Questionnaire data showed that aided localization was significantly better than aided localization in everyday situations. Self-reports from everyday life, the premium-feature and basic-feature hearing aids yielded essentially the same improved localization performance. Laboratory data showed that, overall, the premium-feature hearing aids yielded more accurate localization than the basic-feature hearing aids when high-frequency stimuli were used, and the listening environment was quiet. Otherwise, the premium-feature and basic-feature hearing aids yielded essentially the same performance in other laboratory tests and in daily life.	MEDIUM Premium-feature and basic-feature hearing aids yielded essentially equal performance in other laboratory conditions and in daily life In hearing aids research, laboratory findings do not always predict everyday performance. Audiologists and hearing aid users require not only laboratory evidence, but also daily life evidence, to make evidence-based decisions when choosing hearing aid technology levels.

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| Johnson et al. (2016) (39) | To explore differences in speech-understanding and listening-effort outcomes for older adults using premium-feature and basic-feature hearing aids in their daily lives | Same study design and population as above

Speech Understanding
American-dialect version of the Four Alternative Auditory Feature test.

Tested conditions simulated everyday environments with soft, average, and loud noise.

Listening effort
Listening effort was measured alongside speech understanding. Participants indicated how effortful they found groups of speech understanding trials to be.
1-“No effort” to 7-“Extreme effort”.

Questionnaires
3 different questionnaires with subscales that assessed real-world speech understanding and/or listening effort: the Abbreviated Profile of Hearing Aid Benefit, the Speech, Spatial and Qualities of Hearing Scale (SSQ), and the Device-Oriented Subjective Outcome (DOSO) Scale

Participant Diaries
Participants received a blank diary in each of the 4 1-month trials. They used the diaries to describe in their own words one communication situation that went well, and one that went poorly, each day for five days at the end of the trial | Speech Understanding
Unaided listening consistently produced poorer scores than each aided listening condition

No contrasts exploring differences between premium-feature and basic-feature HAs were statistically significant.

Listening effort
Listening with HAs significantly reduced listening effort compared to listening without HAs for the soft and average listening environments, but not for the loud listening environment.

Significantly less perceived effort when listening with the premium B HAs compared to the basic B HAs in the loud condition (effect size of d = .36 (p <0.001)). No other comparisons of premium and basic devices were statistically significant.

Questionnaires
There are no clear differences in reported speech-understanding benefit between the basic A and premium A HAs or the basic B and premium B HAs.

Small difference in favour of the premium-feature devices for listening effort, however, analyses showed that these visual trends were not statistically significant.

Participants’ perceived aided speech-understanding benefit in their daily listening environments was not significantly affected on average by the HA technologies that they used | MEDIUM

It is important to acknowledge that implementations of HA features are engineered differently for different manufacturers. The possibility exists that some features are superior for some brands.

Payers should remain circumspect about device benefits without independent proof of real-world effectiveness.

Although it is possible that individuals with different or more complicated hearing losses might obtain greater benefit from premium features, there is no existing evidence to suggest that this would be the case.

Combined results of laboratory measures, self-report questionnaires, and participant diary information all point to a |

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| | | in this research, F (1.801, 79.245) = 0.132, p > 0.05.

Participants’ perceived listening-effort in their daily listening environments was not significantly affected by the HA technologies that they used for this research, F (2.056, 90.449) = 0.044, p > 0.05.

Participant diaries
No defined differences found between premium and basic hearing aids for performance in daily living. | conclusion that premium-feature and basic-feature HAs are capable of providing essentially equivalent improvements to speech understanding and listening effort in daily listening for this population. | | Cox et al. (2016) (37) | To explore reported differences in hearing abilities for adults using premium- and basic-feature hearing aids in their daily lives | Same study design and population as above

Three types of patient-point-of-view data were collected:
* Changes in QoL related to hearing
* Six-item questionnaire encompassing topics that are considered critical for satisfaction with amplification and often targeted in the engineering design of new premium features
* In-depth qualitative interviews to further explore participants’ personal experiences and preferences with the hearing aids. | QoL
There was not a clear difference in the pattern of QoL changes reported across the four hearing aids.

The QoL change responses were scored from −7 (A very great deal worse) to +7 (A very great deal better). The mean scores were 4.93 (brand A basic), 4.62 (brand B basic), 4.87 (brand A premium), and 4.56 (brand B premium).

Not statistically significant differences between basic and premium HAs

Questionnaire
Planned contrasts exploring results for basic and premium devices for the two brands combined and for each brand separately failed to reveal any significant differences (speech clarity, noise bother, wearing HA, listening fatigue, sound comfort or localisation) | MEDIUM

The outlay of substantially higher dollar amounts to purchase premium feature engineering technology typically would not have resulted in meaningful incremental gain in overall effectiveness relative to basic-feature technology. |

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| | | Preference data
Preferences were equally divided between basic- and premium feature devices. Two participants could not differentiate between basic and premium. Mean scores generated by the overall goodness ratings for the four models on the visual analogue scale used in interview 4 were brand A basic = 75.7, brand B basic = 74.4, brand A premium = 72.6, brand B premium = 74.4. There were no significant differences among these means. | | | Wu et al. (2019) (40) | To investigate the laboratory efficacy and real-world effectiveness of advanced directional microphones (DM) and digital noise reduction (NR) algorithms (i.e., premium DM/NR features) relative to basic-level DM/NR features of contemporary hearing aids (HAs). The study also examined the effect of premium HAs relative to basic HAs and the effect of DM/NR features relative to no features. | Single-blinded crossover trial

Population: Fifty-four older adults with mild-to-moderate hearing loss

Two HA models
1) basic-level device (basic HA)
2) advanced-level device (premium HA)

Features of the basic HAs were adaptive DMs and gain-reduction NR with fewer channels. In contrast, the features of the premium HAs included adaptive DMs and gain-reduction NR with more channels, bilateral beam formers, speech-seeking DMs, pinna-simulation directivity, reverberation reduction, impulse NR, wind NR, and spatial NR.

4 trial conditions consisted of | Laboratory data generally supported the use of premium HA features (DM & NR) for speech understanding and localisation performance. Premium HA were supported for speech understanding. For listening effort and sound quality the results were similar across features and premium Vs basic. Small effect sizes for all listening conditions for Premium V Basic (< 0.26)

Retrospective and in-situ self-reports showed there was no strong evidence to support the benefit of premium DM/NR features and premium HAs over basic DM/NR features and basic HAs, respectively.

Although statistically significant in the laboratory, the benefit of premium features might not be large enough to be noticed in the real world. | MEDIUM

Concerns around generalizability, including disabled HA volume controls (which could overestimate the effect of features) and minimal participant training on features

Although both premium and basic DM/NR technologies have the potential to improve HA outcomes, older adults with mild-to-moderate hearing loss are unlikely to perceive the additional benefits provided by the |

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| | | * Factorial combinations of HA model (premium versus basic)
* DM/NR feature status (on versus off)

In each condition, participants wore bilateral HAs for 5 weeks.

Laboratory outcomes;
* Speech understanding (Hearing in Noise Test)
* Listening effort
* Sound quality
* Localization

Retrospective self-reports for HA satisfaction
* Abbreviated Profile of Hearing Aid Benefit
* Speech, Spatial, and Qualities (SSQ) Hearing Scale
* Satisfaction With Amplification in Daily Life (SADL)
* In-situ self-reports (i.e., self-reports completed in the real world in real time). | Because most differences in HINT scores across the four HA conditions were smaller than 3 dB (3 dB is deemed just noticeable), participants might not notice the difference in the real world and therefore did not report it in retrospective and in-situ self-reports. | premium DM/NR features in their daily lives. |

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Hearing impairment and dementia

The Lancet commission on dementia prevention, intervention and care life-course identified 12 modifiable risk factors for dementia. These include (41):

1. Less education
2. Hypertension
3. Hearing impairment
4. Smoking, obesity
5. Depression
6. Physical inactivity
7. Diabetes
8. Infrequent social contact
9. Excessive alcohol consumption
10. Head injury
11. Air pollution

Modification of these 12 risk factors might prevent or delay up to 40% of dementias (41).

Hearing loss has the highest population attributable fraction for dementia. A meta-analysis by the Lancet commission found that those with normal baseline cognition and hearing loss present at a threshold of 25 dB had a relative risk of 1.9 for dementia (in populations followed up over 9–17 years). A subsequent meta-analysis using the same three prospective studies measuring hearing using audiometry at baseline, found an increased risk of dementia (OR 1·3, 95% CI 1·0–1·6) per 10 dB of worsening of hearing loss (42).

A 25-year prospective study of 3777 people aged 65 years or older found increased dementia incidence in those with self-reported hearing problems except in those using hearing aids (43). Similarly, a cross–sectional study found hearing loss was only associated with worse cognition in those not using hearing aids (44). A US nationally representative survey of 2040 people older than 50 years, tested every two years for 18 years, found immediate and delayed recall deteriorated less after initiation of hearing aid use, adjusting for other risk factors (45). Hearing aid use was the largest factor protecting from decline (regression coefficient β for higher episodic memory 1·53; p <0.001) adjusting for protective and harmful factors. The long follow-up times in these prospective studies suggest hearing aid use is protective, rather than the possibility that those developing dementia are

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less likely to use hearing aids. Hearing loss might result in cognitive decline through reduced cognitive stimulation (41).

No evidence could be located which assessed whether the prescription of basic versus premium hearing aids has an impact on the development or progression of dementia. As of 2020, whether hearing aid use can delay the onset of cognitive decline is unknown (46).

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References

1. Lebo CP, Smith MF, Mosher ER, Jelonek SJ, Schwind DR, Decker KE, et al. Restaurant noise, hearing loss, and hearing aids. West J Med [Internet]. 1994; 161(1):[45-9 pp.]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1011367/.
2. Keith R, Talis H. Use of speech in noise in diagnostic audiometry. Journal of Auditory Research [Internet]. 1970; 10(3):[201-4 pp.].
3. Beattie RC, Barr T, Roup C. Normal and Hearing-Impaired Word Recognition Scores for Monosyllabic Words in Quiet and Noise. British Journal of Audiology [Internet]. 1997 1997/06/01; 31(3):[153-64 pp.]. Available from: https://doi.org/10.3109/03005364000000018.
4. Beattie RC, Raffin MJM. Reliability of Threshold, Slope, and PB Max for Monosyllabic Words. Journal of Speech and Hearing Disorders [Internet]. 1985; 50(2):[166-78 pp.]. Available from: https://pubs.asha.org/doi/abs/10.1044/jshd.5002.166.
5. Beattie RC, Zipp JA. Range of Intensities Yielding Pb Max and the Threshold for Monosyllabic Words for Hearing-Impaired Subjects. Journal of Speech and Hearing Disorders [Internet]. 1990; 55(3):[417-26 pp.]. Available from: https://pubs.asha.org/doi/abs/10.1044/jshd.5503.417.
6. Boothroyd A. The Performance/Intensity Function: An Underused Resource. Ear Hear. 2008;29(4):479-91.
7. Dubno JR, Lee F-S, Klein AJ, Matthews LJ, Lam CF. Confidence Limits for Maximum Word- Recognition Scores. Journal of Speech, Language, and Hearing Research [Internet]. 1995; 38(2):[490- 502 pp.]. Available from: https://pubs.asha.org/doi/abs/10.1044/jshr.3802.490.
8. Beattie RC. Word Recognition Functions for the CID W-22 Test in Multitalker Noise for Normally Hearing and Hearing-Impaired Subjects. Journal of Speech and Hearing Disorders [Internet]. 1989; 54(1):[20-32 pp.]. Available from: https://pubs.asha.org/doi/abs/10.1044/jshd.5401.20
9. Dimitrijevic A, John MS, Picton TW. Auditory Steady-State Responses and Word Recognition Scores in Normal-Hearing and Hearing-Impaired Adults. Ear Hear [Internet]. 2004; 25(1):[68-84 pp.]. Available from: https://journals.lww.com/ear- hearing/Fulltext/2004/02000/Auditory_Steady_State_Responses_and_Word.7.aspx.
10. Christensen LA. Directionality in Hearing Aids: A Progress Report.
11. Killion MC. The SIN report: Circuits haven’t solved the hearing-in-noise problem. The Hearing Journal [Internet]. 1997; 50(10):[28-30, 2, 4 pp.]. Available from: https://journals.lww.com/thehearingjournal/Fulltext/1997/10000/The_SIN_report__Circuits_haven _t_solved_the.2.aspx.
12. Nabelek AK, Freyaldenhoven MC, Tampas JW, Burchfiel SB, Muenchen RA. Acceptable noise level as a predictor of hearing aid use. J Am Acad Audiol [Internet]. 2006 Oct; 17(9):[626-39 pp.].
13. Fikret‐Pasa S. The effect of compression ratio on speech intelligibility and quality. The Journal of the Acoustical Society of America [Internet]. 1994; 95(5):[2992- pp.]. Available from: https://asa.scitation.org/doi/abs/10.1121/1.408903.
14. Killion M, Schulein R, Christensen L, Fabry D, Revit L, Niquette P, et al. Real-world performance of an lie directional microphone. Hearing Journal [Internet]. 1998; 51:[24-39 pp.].
15. Killion MC, editor New thinking on hearing in noise: A generalized articulation index2002.
16. Killion MC, Niquette PA, Gudmundsen GI, Revit LJ, Banerjee S. Development of a quick speech-in-noise test for measuring signal-to-noise ratio loss in normal-hearing and hearing-impaired listeners. The Journal of the Acoustical Society of America [Internet]. 2004; 116(4):[2395-405 pp.]. Available from: https://asa.scitation.org/doi/abs/10.1121/1.1784440.
17. Killion MC, Niquette PA. What can the pure-tone audiogram tell us about a patient’s SNR loss? The Hearing Journal [Internet]. 2000; 53(3):[46-8, 50, 2-3 pp.]. Available from:

Research Request – Guidance for prescribing premium versus basic level hearing aids P a g e | 25 Page 42 of 113

https://journals.lww.com/thehearingjournal/Fulltext/2000/03000/What_can_the_pure_tone_audio gram_tell_us_about_a.6.aspx. 18. Miller C. The role of aided signal-to-noise ratio in aided speech perception in noise 2013. 19. Anderson S, Parbery-Clark A, Yi H-G, Kraus N. A neural basis of speech-in-noise perception in older adults. Ear Hear [Internet]. 2011 Nov-Dec; 32(6):[750-7 pp.]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3189261/. 20. Schneider BA. How Age Affects Auditory-Cognitive Interactions in Speech Comprehension. Audiol Res [Internet]. 2011; 1(1):[e10-e pp.]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4627150/ 21. Souza P, Arehart K, Miller CW, Muralimanohar RK. Effects of age on F0 discrimination and intonation perception in simulated electric and electroacoustic hearing. Ear Hear [Internet]. 2011; 32(1):[75-83 pp.]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3010262/. 22. Pumford JM, Seewald RC, Scollie SD, Jenstad LM. Speech recognition with in-the-ear and behind-the-ear dual-microphone hearing instruments. Journal of the American Academy of Audiology [Internet]. 2000 2000/01//; 11(1):[23-35 pp.]. Available from: http://europepmc.org/abstract/MED/10741354. 23. Valente M, Fabry DA, Potts LG. Recognition of speech in noise with hearing aids using dual microphones. J Am Acad Audiol [Internet]. 1995 Nov; 6(6):[440-9 pp.]. 24. McShefferty D, Whitmer WM, Akeroyd MA. The Just-Noticeable Difference in Speech-to- Noise Ratio. Trends in Hearing [Internet]. 2015; 19:[2331216515572316 p.]. Available from: https://journals.sagepub.com/doi/abs/10.1177/2331216515572316. 25. Walden BE, Surr RK, Cord MT, Edwards B, Olson L. Comparison of benefits provided by different hearing aid technologies. J Am Acad Audiol [Internet]. 2000 Nov-Dec; 11(10):[540-60 pp.]. 26. Beck D, Benite L. A Ttwo-minute speech in noise test - Protocol and Pilot Data. Audiology Today [Internet]. 2019; 31(3):[28-34 pp.]. 27. Killion MC. Myths about hearing in noise and directional microphones. Hearing Review [Internet]. 2004; 11(2):[14-21 pp.]. Available from: http://www.etymotic.com/media/publications/erl-0051-2004.pdf. 28. Carhart R. Tests for selection of hearing AIDS. The Laryngoscope [Internet]. 1946; 56(12):[780-94 pp.]. Available from: https://onlinelibrary.wiley.com/doi/abs/10.1288/00005537- 194612000-00004. 29. Berger KW. Prescription of hearing aids: a rationale. J Am Audiol Soc [Internet]. 1976 1976 Nov-Dec; 2(3):[71-8 pp.]. Available from: http://europepmc.org/abstract/MED/1002581. 30. Walden BE, Holum-Hardegen LL, Crowley JM, Schwartz DM, Williams DL. Test of the Assumptions Underlying Comparative Hearing Aid Evaluations. Journal of Speech and Hearing Disorders [Internet]. 1983; 48(3):[264-73 pp.]. Available from: https://pubs.asha.org/doi/abs/10.1044/jshd.4803.264. 31. Killion MC, Gudmundsen GI. Fitting hearing aids using clinical prefitting speech measures: an evidence-based review. Journal of the American Academy of Audiology [Internet]. 2005; 16(7):[439- 47 pp.]. Available from: https://doi.org/10.3766/jaaa.16.7.4. 32. Jerger J, Hayes D. Hearing Aid Evaluation: Clinical Experience With a New Philosophy. Archives of Otolaryngology [Internet]. 1976; 102(4):[214-25 pp.]. Available from: https://doi.org/10.1001/archotol.1976.00780090056008. 33. Beck DL. Speech-in-noise test results for Oticon Opn2017. Available from: https://www.hearingreview.com/hearing-loss/patient-care/evaluation/speech-noise-test-results- oticon-opn. 34. Shanks JE, Wilson RH, Larson V, Williams D. Speech Recognition Performance of Patients with Sensorineural Hearing Loss Under Unaided and Aided Conditions Using Linear and Compression Hearing Aids. Ear Hear [Internet]. 2002; 23(4):[280-90 pp.]. Available from:

Research Request – Guidance for prescribing premium versus basic level hearing aids P a g e | 26 Page 43 of 113

https://journals.lww.com/ear- hearing/Fulltext/2002/08000/Speech_Recognition_Performance_of_Patients_with.3.aspx. 35. Chasin M. Slope of PI Function is not 10%-per-dB in Noise for All Noises and All Patients. Hearing Review [Internet]. 2013; 20(11):[1 p.]. Available from: https://www.hearingreview.com/hearing-loss/patient-care/back-to-basics-slope-of-pi-function-is- not-10-per-db-in-noise-for-all-noises-and-for-all-patients. 36. Gioia C, Ben-Akiva M, Kirkegaard M, Jørgensen O, Jensen K, Schum D. Case factors affecting hearing aid recommendations by hearing care professionals. J Am Acad Audiol [Internet]. 2015 Mar; 26(3):[229-46 pp.]. 37. Cox RM, Johnson JA, Xu J. Impact of Hearing Aid Technology on Outcomes in Daily Life I: The Patients’ Perspective. Ear Hear [Internet]. 2016 Jul-Aug; 37(4):[e224-e37 pp.]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4925253/. 38. Johnson JA, Xu J, Cox RM. Impact of Hearing Aid Technology on Outcomes in Daily Life III: Localization. Ear Hear [Internet]. 2017 Nov/Dec; 38(6):[746-59 pp.]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5659949/. 39. Johnson JA, Xu J, Cox RM. Impact of Hearing Aid Technology on Outcomes in Daily Life II: Speech Understanding and Listening Effort. Ear Hear [Internet]. 2016 Sep-Oct; 37(5):[529-40 pp.]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4998844/. 40. Wu Y-H, Stangl E, Chipara O, Hasan SS, DeVries S, Oleson J. Efficacy and Effectiveness of Advanced Hearing Aid Directional and Noise Reduction Technologies for Older Adults With Mild to Moderate Hearing Loss. Ear Hear [Internet]. 2019; 40(4). Available from: https://journals.lww.com/ear- hearing/Fulltext/2019/07000/Efficacy_and_Effectiveness_of_Advanced_Hearing_Aid.5.aspx. 41. Livingston G, Huntley J, Sommerlad A, Ames D, Ballard C, Banerjee S, et al. Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. The Lancet [Internet]. 2020; 396(10248):[413-46 pp.]. 42. Loughrey DG, Kelly ME, Kelley GA, Brennan S, Lawlor BA. Association of Age-Related Hearing Loss With Cognitive Function, Cognitive Impairment, and Dementia: A Systematic Review and Meta- analysis. JAMA Otolaryngology–Head & Neck Surgery [Internet]. 2018; 144(2):[115-26 pp.]. Available from: https://doi.org/10.1001/jamaoto.2017.2513. 43. Amieva H, Ouvrard C, Meillon C, Rullier L, Dartigues J-F. Death, Depression, Disability, and Dementia Associated With Self-reported Hearing Problems: A 25-Year Study. The Journals of Gerontology: Series A [Internet]. 2018; 73(10):[1383-9 pp.]. Available from: https://doi.org/10.1093/gerona/glx250. 44. Ray J, Popli G, Fell G. Association of Cognition and Age-Related Hearing Impairment in the English Longitudinal Study of Ageing. JAMA Otolaryngology–Head & Neck Surgery [Internet]. 2018; 144(10):[876-82 pp.]. Available from: https://doi.org/10.1001/jamaoto.2018.1656. 45. Maharani A, Dawes P, Nazroo J, Tampubolon G, Pendleton N, group obotS-CW. Longitudinal Relationship Between Hearing Aid Use and Cognitive Function in Older Americans. Journal of the American Geriatrics Society [Internet]. 2018; 66(6):[1130-6 pp.]. Available from: https://onlinelibrary.wiley.com/doi/abs/10.1111/jgs.15363. 46. Sarant J, Harris D, Busby P, Maruff P, Schembri A, Lemke U, et al. The Effect of Hearing Aid Use on Cognition in Older Adults: Can We Delay Decline or Even Improve Cognitive Function? J Clin Med [Internet]. 2020 Jan 17 PMC7020090]; 9(1).

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