Diploma in Biomedical Engineering
Audiometry and Hearing Devices
Declaration of Originality
Yong Wen Xin
Goh Keng Swee Darren
Catalina Karlyn Koh
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1. Patient Assessment
1.1 Patient Information
Colin is a Chief Financial Officer in his mid 40s who works long hours in a multinational company.
Lately, he found it difficult to follow board meetings and multi speaker teleconferences. The ability to hear and communicate well is very important to his career and he would like to find the best solution to his problem.
However, Colin is very self-conscious and does not want to give others the impression that he is less capable by wearing hearing aids.
Some identification information regarding the patient is missing, such as:
1) NRIC/ FIN number
2) Name of company
These background information regarding hearing are also not know:
1) A more specific date of hearing loss experienced
2) The ear that experienced hearing loss
3) Gradualness/ suddenness of hearing loss
4) Any visit to a doctor/ operation done regarding his ear beforehand
5) Sensitivity to loud sound
6) Genetic information
7) Exposure to excessive noise at work or if loud music is listened frequently
8) Numbness on face
9) Episodes of dizziness
10) Wellness during hearing test
It is known that certain background information can be assumed from patient information however to ensure an accurate diagnosis and hearing treatment is given, it is best to inquire these questions.
Furthermore, these important noise exposure information are also not known (if Colin is exposed to excessive noise):
1) Duration of noise exposure in years
2) Usage of hearing protectors when exposed to excessive noise
3) Had counselling on usage of hearing protectors
Due to the lack of these information, an accurate in-depth diagnosis and treatment cannot be given even if hearing loss is evident in hearing test.
As hearing loss is suspected, intensity of 70dB is used to start the presentation.
2. Pure Tone Audiometry (PTA) Results
2.1 Audiogram (Catalina)
Fig 1. BC testing for frequency with AC threshold Fig 2. BC masking on Right ear
Results: Colin has mild to moderately severe Sensorineural Hearing Loss on the left ear and Moderate to Severe Sensorineural Hearing Loss on the right ear.
2.2 Audiogram (Rooney)
Result: Mr Colin is suffering from mild conductive hearing loss on his right ear at frequencies 250 Hz and 500 Hz. He also has moderate severe hearing loss at frequencies 3kHz, 4kHz and 8kHz on his left ear.
2.3 Audiogram (Wen Xin)
Fig 6. Audiogram before conducting AC Mask Fig 7. Audiogram after conducting AC Mask
Result: Mild to moderately-severe SNHL at high frequencies on the left ear and mild to severe downward sloping SNHL from low to high frequencies on the right ear.
2.4 Audiogram (Darren)
Result: Mild to moderate-severe SNHL at high frequencies for the left ear. Gradual decline mild to moderate-severe SNHL for the right ear.
3. Speech Frequencies
According to Centers for Disease Control and Prevention 1, the frequency of speech sound ranges from 250Hz to 6000Hz. The vowel sounds occupy the low frequency range of 250Hz to 1000Hz, while the consonant sounds have higher frequencies, ranging from 1500Hz to 6000Hz. It is also stated that the consonant sounds help listeners to perceive speech better as compared to vowel sounds 1. It is shown in the new Count-The-Dot method the calculation of Articulation Index (AI) 2, the number of dots occupying the vowel region are lesser (37 dots) than the consonant region (52 dots).
Fig 12. Count-The-Dot audiogram
Obtained from: http://journals.lww.com/thehearingjournal/Fulltext/2010/01000/Twenty_years_later__A_NEW_Count_The_Dots_method.3.aspx
Furthermore frequencies ranging from 2000Hz to 3000Hz are more important in speech understanding due to higher classes of phonemic information3.
4. Analysis of Colin’s Audiogram (Overall)
Fig 14. Colin’s audiogram with the “Speech Banana” added5
According to Colin’s audiogram, as shown in the Fig14, Colin is unable to hear speech sounds ranging from 2000Hz to 8000Hz on the right ear and 3000Hz to 8000Hz on the left ear unaided. These are in consonant components in speech sound frequency range.
Figure 15. Unaided Colin’s audiogram with Mueller-Killion Count-The-Dots audiogram form2
Using the AI value, an approximate 2% of sentences loss, 92% intelligence in 250 Single Syllable MRT Rhyming Words and 65% of 1000 Single Syllable Words PBs respectively is obtained. The AI values also shows that Colin shows poorer performance in conversational speech 3, as he is not able to interpret the speech information transmitted fully. Thus, Colin is able to hear speeches, but he is not able to comprehend them fully because the whole frequency range is not heard properly. This is the reason that caused him to be unable to follow at board meetings and multi speaker teleconferences well. The situation will worsen in the noisy environment as noise will mask the low frequency speech sounds.
5.1 Hearing Aids
We are able to recommend Colin with two different type of Hearing aids.
Fig 17. ITC (In the Canal)
The In the Canal (ITC) fits in the ear canal partly, it comes with a volume control and program button, thus the inability to completely fit in the canal.
The ITC is suitable for Colin as it is suitable for users with moderate to severe hearing loss.
Since Colin is self- conscious this ITC is barely visible and is comfortable because it sits deep in the ear canal.
The Behind the Ear (BTE) is cased in a plastic cover that will rest behind Colin’s ear, a clear plastic acoustic tube will then directly amplify sound into an earbud that is fitted inside the ear canal. The clear plastic acoustic tube is small and will be barely visible.
It is suitable for Colin as he has moderate to severe hearing loss. Also, it is comfortable as it prevents a plugged up feeling in ear canal
5.2 Lip Reading or Speech Reading
We also recommend Colin to learn lip reading or speech reading because it is useful for following conversational speech.
1″About Sound | Hearing Loss | NCBDDD | CDC”, Cdc.gov, 2015. Online. Available: https://www.cdc.gov/ncbddd/hearingloss/sound.html#modalIdString_CDCImage_0. Accessed: 31- Dec- 2017.
2M. Killion and H. Mueller, “Twenty years later: A NEW Count-The-Dots method”, 2010. Online. Available: http://journals.lww.com/thehearingjournal/Fulltext/2010/01000/Twenty_years_later__A_NEW_Count_The_Dots_method.3.aspx. Accessed: 01- Jan- 2018.
3D. Schum, “What Determines Speech Understanding? Donald J. Schum”, AudiologyOnline, 2012. Online. Available: https://www.audiologyonline.com/articles/what-determines-speech-understanding-7056. Accessed: 01- Jan- 2018.
4H. Mueller and M. Killion, “Testing and Fitting”, Etymotic.com, 1990. Online. Available: https://www.etymotic.com/media/publications/erl-0020-1990.pdf. Accessed: 01- Jan- 2018.
5M. Ross, “The Audiogram: Explanation and Significance”, 2004. Online. Available: http://www.hearingloss.org/sites/default/files/docs/Ross_Audiogram_MJ04.pdf. Accessed: 1- Jan – 2018.
6L. Humes, “Understanding the speech-understanding, Problems of the hearing impaired”, Indiana.edu, 1991. Online. Available: http://www.indiana.edu/~audres/Publications/humes/papers/60_Humes.pdf. Accessed: 01- Jan- 2018.
7″Hearing Loss and Older Adults”, NIDCD, 2016. Online. Available: https://www.nidcd.nih.gov/health/hearing-loss-older-adults. Accessed: 01- Jan- 2018
8″Hearing Aids Buying Guide”, Consumer Reports, 2017 Online. Available: https://www.consumerreports.org/cro/hearing-aids/buying-guide. Accessed 28- December- 2017
Number of Words (excluding references): 963