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Trial registered on ANZCTR


Registration number
ACTRN12610000664044
Ethics application status
Approved
Date submitted
6/08/2010
Date registered
16/08/2010
Date last updated
16/08/2010
Type of registration
Retrospectively registered

Titles & IDs
Public title
Comparison of real ear and simulated insertion gain in adults who use hearing aids
Scientific title
Retrospective study with comparison of real ear and simulated insertion gain in adults who use hearing aids
Secondary ID [1] 252424 0
Nil
Universal Trial Number (UTN)
U1111-1116-4244
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Hearing Loss 257901 0
Condition category
Condition code
Ear 258063 258063 0 0
Deafness

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The real ear measurements are objectives and fast (about 10 minutes) measures of the sound pressure level in the ear canal.
The equipment consists of a computer, a speaker, a reference microphone and a tiny tube that is linked with a measure microphone.
The computer’s screen displays the patient’s data, the audiometric data and the graphics obtained with the real ear measurements. The audiologists control all parameters necessary on the computer.
The speaker provides the acoustic signal for the measurements. The type of the signal depends on the hearing aid features (e.g. if they have feedback management or/and noise redactor) and the signal level depends on the hearing aid processing (e.g. if they have Automatic Gain Control or Wide Dynamic Range Compression) and the prescription rule, for example, National Acoustic Laboratories Non Linear number 1 (NAL-NL1), National Acoustic Laboratories Review (NAL-R), Prescription of Gain and Output (POGO).
The data about the real ear measures are displayed in a graphic form where the information about the sound frequency is showed in the horizontal axis and the sound pressure level is showed in the vertical axis.
The reference microphone controls the signal level around the patient’s ear and the tiny tube linked with a microphone measures the sound pressure level inside the ear canal.
Firstly, we assess the Real Ear Unaided Response, which is the measure of the sound pressure level in a specific point of the ear canal while the patient is not using the hearing aid. This is the response about the amplification provided by the open ear.
After this, we measure the Real Ear Occluded Response, which is the sound pressure level in a specific point of the ear canal while the patient is using the hearing aid off. This measure reflects the coupling of the hearing aid off and the earmold with the ear. This is the amount of amplification that is lost with the ear occlusion.
Ultimately, is obtained the Real Ear Aided Response, which is the sound pressure level in a specific point of the ear canal while the patient is using the hearing aid on. This measure reflects the coupling of the hearing aid on and the earmold with the ear. This is the amount of amplification provided by the hearing aid.
The insertion gain is the difference of the measurement obtained in real ear whilst the participant did not wear hearing aids (REUR) and whilst they did wear hearing aids (REAR). This measure is compared with individual amplification targets provided by fitting rules based on the audiometric data.
This measurements are important at the verification step of amplification provided by hearing aids and at follow up sessions because is a objective and fast measure (about ten minutes) of the sound pressure level in the ear canal. Moreover, these measures are individual ones and reflect the sound pressure level when the hearing aids are in use.
The real ear insertion gain can be obtained on several occasions. At the moment of verification these measures are used to compare the targets provided by a prescription rule with the amplification provided by the hearing aid. At follow up sessions that is defined according to each patient. In these occasions the measure helps us to fine tuning the amplification providing more or less amplification according to the targets. The real ear measurements can be obtained more than two times.
Intervention code [1] 256951 0
Treatment: Devices
Comparator / control treatment
The real ear insertion gain was obtained like description on the item “Description of intervention exposure” and the data about the simulated insertion gain was registered from the hearing aid manufacturer’s software.
Currently, with the technology advance, the sale of digital hearing aids has increased and more people start to use this technology.
The digital hearing aids are programmed by a computer interfaced with software that is developed by the hearing aid manufacturer.
In general, all hearing aid manufacturers’ software displays on the computer screen some information about the eletroacoustic features (gain, output, compression, etc) and the special features (types of hearing aid’s microphones, feedback management, noise reductor, etc).
Furthermore, are displayed some simulations, that try show how the amplification is working according to the audiometric data inserted on the software. During all the programming session the simulated insertion gain is available and the time of each session can vary according to each patient (more or less than thirty minutes). But these simulations are generated by average values about the ear canal and its coupling with the hearing aid. So, the simulation is not an individualized measure.
Some audiologists tend to believe that the simulations reflect the real ear measures, but some studies have been showed that this belief is not true.
So, is important to know if there are differences between the real ear insertion gain and the simulated insertion gain.
The data about real ear insertion gain and the simulated insertion gain was collected on the same participant.
Control group
Active

Outcomes
Primary outcome [1] 258923 0
The insertion gain simulated in software programming of hearing aids was higher than the real ear insertion gain obtained with the probe microphone measures. With the "t" paired test was observed that there was statistically significant difference over the frequencies, significance level equal 5%.
Timepoint [1] 258923 0
Normally, the primary outcome was assessed during the hearing aids' tests or follow up sessions, 1 month after the adaptation of the hearing aid. But this measurement can be assessed in any time after the adaptation.
The experience with the use of hearing aids doesn't influence the results tests.
Secondary outcome [1] 265095 0
There was no correlation (with Pearson's correlation) from age to the difference of real ear measures and measures simulated.
Timepoint [1] 265095 0
Normally, the secondary outcome was assessed during the hearing aids' tests or follow up sessions, 1 month after the adaptation of the hearing aid. But this measurement can be assessed in any time after the adaptation.
The experience with the use of hearing aids doesn't influence the results tests.
The secondary outcome was assessed at the same time with the primary outcome.

Eligibility
Key inclusion criteria
Adults with sensorioneural hearing loss and using hearing aids
Minimum age
18 Years
Maximum age
93 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
For this study, the participants can't be a child (only adults), the hearing loss can't be because conductive problems.

Study design
Purpose of the study
Treatment
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Other
Other design features
All participants received all the interventions, but is different from the crossover design because the sequence was not controlled.
The data about each participant was colected once. At the same session we collected the information about the simulated insertion gain and about the real ear insertion gain.
The data were compared on the same participant using the statistical test "t" paired. However there was not the need to control the sequence of each intervention. So, the design is not a crossover study.
Because of the participantes are assigned to receiving one of two or more interventions are not single group studies.
Because is not different groups of participants receiving differents interventions during the same time, the study is not parallel.
And, finally is not factorial because is not a randomized study.
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
5/05/2010
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
62
Accrual to date
Final
Recruitment outside Australia
Country [1] 2807 0
Brazil
State/province [1] 2807 0
Sao Paulo

Funding & Sponsors
Funding source category [1] 257412 0
University
Name [1] 257412 0
University of Sao Paulo
Country [1] 257412 0
Brazil
Primary sponsor type
Individual
Name
Patricia Danieli Campos
Address
Prudente de Moraes St, n. 8-54
Vila Falcao, Bauru/SP
CEP: 17051-010
Country
Brazil
Secondary sponsor category [1] 256641 0
Individual
Name [1] 256641 0
Deborah Viviane Ferrari
Address [1] 256641 0
Al. Octavio Pinheiro Brisola, 9-75
Vila Universitaria, Bauru/SP
CEP: 17012-901
Country [1] 256641 0
Brazil

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 259436 0
Comite de Etica em Pesquisa da Faculdade de Odontologia de Bauru
Ethics committee address [1] 259436 0
Al. Octavio Pinheiro Brisola, 9-75
Vila Universitaria, Bauru/SP
CEP: 17012-901
Ethics committee country [1] 259436 0
Brazil
Date submitted for ethics approval [1] 259436 0
05/02/2010
Approval date [1] 259436 0
Ethics approval number [1] 259436 0
020/2010

Summary
Brief summary
Background: the development of hearing aids (HA) software programming does not replace the analysis performed in real ear using probe microphone measures. Aim: to compare the simulated insertion gain in the software programming of HA and the real ear insertion gain. Method: 62 patients (aging from 29 to 93 years, 30 men and 32 women) were enrolled in this study. All the patients presented unilateral (n = 14) or bilateral (n = 48) varying from mild to profound sensorineural hearing impairment. Thus, 110 ears assessed. The data collection from medical records was registered and the insertion gain obtained in real ear was compared to the insertion gain simulated in software programming of HA. Statistical test was used to analyze the correlation of data from the difference of the real ear gain and the simulated insertion gain. Results: the insertion gain simulated in software programming of HA was higher than the real ear insertion gain obtained with the probe microphone measures. There was statistically significant difference over the frequencies. There was no correlation from age to the difference of real ear measures and measures simulated. Conclusion: the use of real ear measures is important during the verification of the HA.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 31484 0
Address 31484 0
Country 31484 0
Phone 31484 0
Fax 31484 0
Email 31484 0
Contact person for public queries
Name 14731 0
Patricia Danieli Campos
Address 14731 0
Prudente de Moraes St, 8-54, Vila Falcao, Bauru/SP
CEP: 17051-010
Country 14731 0
Brazil
Phone 14731 0
+55 14 32242922
Fax 14731 0
Email 14731 0
[email protected]
Contact person for scientific queries
Name 5659 0
Patricia Danieli Campos
Address 5659 0
Prudente de Moraes St, 8-54, Vila Falcao, Bauru/SP
CEP: 17051-010
Country 5659 0
Brazil
Phone 5659 0
+55 14 32242922
Fax 5659 0
Email 5659 0
[email protected]

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