Exam 1 Flashcards
After wearing the device for several weeks Varuka indicates voices lack clarity and she’d like to hear more soft consonants. Which adjustment will improve her concerns?
Decrease the input level of the first TK to increase the output of soft signals.
Standing waves in a thin tube change a hearing aid’s final output and frequency response by:
- Attenuating high frequency output.
- Attenuating low frequency output
- Reducing high frequency output and shifting the tubes resonance from 1k Hz to 800 Hz
- Shifting the tubes resonance from 1k Hz to 800 Hz
Reducing high frequency output and shifting the tubes resonance from 1k Hz to 800 Hz
Standing waves in an enclosed space can enhance or attenuate an output signal.
In this case, the standing waves attenuate high-frequency output, while shifting the tube resonance to the lower frequencies (it shifts from1k Hz down to around
800 Hz)
TRUE/FALSE Smaller receivers with stiffer diaphragms supply greater high-frequency output than larger receivers.
True
The Smaller the receivers the higher frequency you can produce. However the larger the receiver the more gain you will get. Or you can do dual receivers
Briefly describe TWO different ways to reduce complaints of the occlusion.
1) increased Vent
* OE can be reduces with an increased vent becuase it will help to release the trapped signals from
* and plugged, boomy, echoy from internal nosie and voise
° by giving re signals/energy some where to go and not be trapped
2) 2mm beyond second bend
* OE often occurs due to the vibrations that travel along the cartilagions portion of the canal.
* by exteding the ear mold 2mm beyond the second bend and you will be reaching the bony part of the canal= no more vibrations of cartilaginous portion because it is now on bone
Your patient is an engineer who’s bothered by the sound of her refrigerator. They downloaded an app and found the signal’s intensity is 24 dB. The first TK in the device is set to compress when the input reaches 30 dB SPL. Which features should be adiusted to reduce the complaint.
Expansion
Wide Dynamic Range Compression TK & CR
low threshold kneepoint and low compression ratio
Output Limiting Compression TK,CR
High threshold kneepoint and high compression ratio
What is DNR, Digital Noise Reduction
define, benefits & limitations
Lowers, minimizes, reduces any signal that remains steady over a long period of time. ( applied to steady state noise)
Benefits
- Improves listening Comfort
- reduces listening effort
-reduces cognitive load
Limitations
-The more Broadband noise, the greater the effect on speech
- Can attenuate some speech sounds if noise that being attenuated is also Within the same frequency range as the speech sounds
- cannot improve speech intelligibility
Describe how frequency resolution changes with SNHL. Why does reduced frequency resolution make it difficult to understand speech in noise?
- The sharp peak of the tuning curve supplies the frequency resolution needed for speech intelligibility in noise
- When the tuning cure is broad it is hitting more frequencies rather then just the one intended frequency - when Frequency resolution is decreased primary signal is no longer enhanced making it difficult to differentiate the desired signal (speech) from the undesired signal (noise) = understanding is diminished
- A decrease in frequency resolution is a decrease in a sharp tuning curve= broad tuning curve
Define temporal resolution and the auditory processes which support it.
Temporal resolution: Is the auditory systems ability to detect small time related changes in acoustic stimuli over time. This is needed to understand speech in noise.
Time Related Cues:
Gap Detection
Phonetic Duration
Temporal Ordering
Suprasegmentals
Gap Detection
Gap Detection- being able to detect the gap or break in a sound or speech. Example: beep being presented closer and closer together until you can no longer hear the break
Describe the benefits spatial hearing supplies
ILD & ITD
Interaural timing differences (ITD)
Timing is the amount of time difference that it take to reach one ear versus the other
Important frequencies: Low frequencies
Because you notice more change in the lows
Interaural level differences (ILD)
ILD is the difference of sound level (intensity) between the two ears if its localized or louder on one side (becuase it is of mass attenuation head)
Important frequencies: high frequency
Because you notice more change in the
Interaural timing differences (ITD)
Timing is the amount of time difference that it take to reach one ear versus the other
Important frequencies: Low frequencies
Because you notice more change in the lows
Interaural level differences (ILD)
ILD is the difference of sound level (intensity) between the two ears if its localized or louder on one side (becuase it is of mass attenuation head)
Important frequencies: high frequency
Because you notice more change in the
Which frequencies supply the most information on interaural level differences?
Important frequencies: high frequency
Which frequencies supply the most information on interaural Timing differences?
Important frequencies: low frequency
How are receivers designed differently to achieve the greatest high frequency output for severe hearing losses
The Smaller the receivers the higher frequency you can produce. However the larger the receiver the more gain you will get. Or you can do dual receivers
Solution: Two receiver system
- Two receivers in one HA
- One with a Stiff Armutre
-Optimized for high frequencies
-One with a Flexible Armature
-Optimized for low frequencies
-Signals combine before final output
-Benefit high frequency bandwidth
-Reduced battery drain
Minimizes saturation duration
Describe 3 methods used to reduce external feedback
-Increase snugness of mold to reduce size of slit leaks & Decrease vent size to stop feedback path
-Digital notch filtering
-Digital feedback cancellation – the best option
Digital notch filtering
what is it, what is it used for and cons?
- reduces external feedback
- Works by removing a narrow band of frequencies around the feedback
- Creates a notch in frequencies so we can not amplify to those frequencies
Potential Con:
-Stops the audibility of important speech sound- reduced speech intelligibility
Digital feedback cancellation
- reduces external feedback
-When a feedback path is detected, the phase cancellation algorithm mimics the feedback and creates a clone of this signal. Within the hearing aid, this clone is subtracted from the amplification path, therefore breaking the loop.
Cons:
Entrainment - environment sound mimics feedback makes clone; patient can hear clone.
Con: not all HA companies have accurate/good Digital Feedback cancellation
Increase snugness of mold to reduce size of slit leaks & Decrease vent size to stop feedback path
- reduces external feedback
- Essentially the same thing – decrease the vent size increases the snugness
Count as one on exam
Con:
-Occlusion Effect
What is Entrainment?
- Occurs during digital Feedback cancellation
- environmental sound mimics feedback, makes a clone; patient can hear clone
what is frequency lowering and name three types of FL
- frequency lowering attempts to improve high frequency audibility by shifting them to lower frequency
- Linear frequency transportation
- non-linear frequency compression
- Spectral envelope warping
Linear frequency transportation
Type of frequency lowering
- Moves a high frequency band one octave down to a lower frequency region
- the moved frequency components are mixed with any low frequencies present
non-linear frequency compression
Type of frequency lowering
- High frequencies are compressed into a lower frequency range
Spectral envelope warping
Type of frequency lowering
- Copy and keep approach
- High frequency signals are transported to a lower frequency band but simultaneously remains present in its original tonotopic position
Describe how inclusion of a case history review of systems assists clinical decision-making
IDENTIFYING COMORBIDITIES LEADS TO IMPROVED TREATMENT OUTCOMES
- Helps us to anticipate progression of loss
-Identification of comorbidities leads to improved treatment outcomes.
-Its best practices, you are able to distinguish yourself from hearing dispensers and other audiologist
-You will have better outcomes for OTC
Create a list of comorbidities linked to hearing loss. Highlight the most common comorbidities prevalent in older populations
Visual Impairment and Reduced manual dexterity
Cognitive Issues
Depression
Falls
Hypertension & Diabetes
What are some Systemic chronic health conditions linked to Progressive HL?
Gastrointestinal: Crohn’s disease
Musculoskeletal: Rheumatoid arthritis, Fibromyalgia
Respiratory: Asthma
Cardiac: Congenital heart disease
Lymphatic: autoimmune disorders
Hematology: anemia, Leukemia
Integumentary: Shingles, Herpes zoster, Ramsay Hunt syndrome
Nervous system: Parkinson’s disease