Exam 5 (SLHS 460)

What are the 3 systems responsible for maintaining balance the role of the cerebellum? (5.1)

1. visual system 

2. somatosensory system 

3. vestibular system 

The cerebellum coordinates the 3 systems. You need all 3 systems for perfect balance, but if one system goes out sometimes other systems can take control. 

What is the vestibular-ocular reflex (VOR)? (5.1)

A reflex where activation of the vestibular system of the inner ear causes eye movement.

What does the brain use the VOR for? (5.1)

It attempts to keep your gaze stable as your head moves around.

Why is the VOR relevant to the vestibular test battery? (5.1)

The VOR is relevant to vestibular test batteries because assessment of the vestibular system can be test through it. Inaccurate vestibular information leads to blurred vision as the visual target slips from the fovea.

Be able to label this anatomy on a figure: each semicircular canal, the ampullae, the otolith organs (utricle and saccule) (5.1)

How is angular acceleration coded? (5.1)

By the semicircular canals, there are 3, one for each dimension of our world.

The ampullae are located at the base of each semicircular canal. Ampulla are sensory hairs embedded in the crista ampullaris, the sensory receptor responsible for detecting angular acceleration. 

Angular Velocity (5.1)

When you turn your head, endolymph pushes on the gelatinous cupula and causes a shearing of the vestibular sensory cells due to inertia. One side is excitatory and the opposite is inhibitory. The velocity of fluid movement provides information about the strength of rotation.

Excitatory: shearing toward kinocilium

Inhibitory: shearing away from kinocilium

How is linear acceleration coded? (5.1) 

Change in velocity. The utricle and saccule, which both contain macula. The macula is analog to the ampullae that detect linear acceleration.

What are the sensory receptors of the vestibular system? (5.1)

crista ampullaris and macula

Which of the semicircular canals form ‘teams’? (5.1)

1. horizontal pair

2. right anterior and left posterior (RALP)

3. left anterior and right posterior (LARP)

The pairs lie in the same plane of motion, hence why they form teams.

What do the utricle and saccule contain? (5.1)

Utricle: macula on the floor (horizontal plane)

Saccule: macula on the wall (vertical plane) 

Otoconia (5.1)

Stimulates the sensory cells in the utricle and saccule. It is located in the gelatinous structure right above the stereocilia. Otoconia also get pulled by gravity: inertia increases the displacement of the stereocilia to enhance vestibular function.

Define Vertigo (5.2)

A false sensation of self or environmental motion

How is vertigo different from other dizziness sensations such as lightheadedness, imbalance, disorientation, and motion intolerance? (5.2)

lightheadedness: one feels that if the sensation worsened they may pass out

imbalance: unsteadiness while walking

disorientation: confusion

motion intolerance: either physical (self) or visual (environmental) motion produces symptoms of nausea or a dizziness sensation

What are the common causes and mechanisms underlying vertigo? (5.2)

• 50% is related to the vestibular system

• low blood pressure

• anemia

• hypoglycemia

• heart disease

• decrease in blood volume

• otitis media

• dehydration

• migraine

• psychological

• idiopathic (unknown)

What is the difference between labyrinthitis and neuritis?  (5.2)

labyrinthitis: infects both auditory and vestibular systems

neuritis: infection affects only the vestibular system

What is the difference between the causes of labyrinthitis and neuritis (viral or bacterial)? (5.2)

• both can be caused by viral or bacterial

• viral: infection enters via bloodstream, symptoms

GO BACK SLIDES 13/14

Key Symptoms and Pathophysiology of Labrynthitis (5.2)

slides 13/14 confused

Key Symptoms and Pathophysiology of Neuritis (5.2)

slides 13/14 confused

What is the cause of Benign Paroxysmal Positional Vertigo? (5.2)

The otoconia are displaced to the semicircular canals.

Symptoms of Benign Paroxysmal Positional Vertigo (5.2)

1. dizziness associated with change in position

2. changing head position changes the gravity forces on the otoconia

3. stronger vertigo with faster movement

Outline the general treatment approaches for BPPV, including the Epley maneuver and other repositioning techniques. (5.2)

series of head maneuvers that attempt to move the otoconia into utricle where they are dissolved 

1. the epley maneuver- identifies bbppv posterior

2. lempert (BBQ) maneuver- horizontal

3. deep head hanging maneuver- superior

Describe the typical causes of Meniere’s Disease. (5.2)

1. obstruction of endolymphatic duct

2. endolymphatic pressure fluctuates 

3. membranous labyrinth becomes swollen when pressure is high and may burst

Discuss the audiological and vestibular impacts of Meniere’s disease. (5.2)

• obstructs the endolymphatic duct

• endolymphatic pressure fluctuates

• membranous labyrinth swells and may burst

• hair cell death over time

• mechanical changes to the ear: utricle & saccule dilation, chronic unsteadiness

Explain the treatment options available for managing Meniere’s disease. (5.2)

• diet change (low salt, no caffeine, no alcohol)

• diuretics

• vestibular rehab

• direct gentamicin injects to kill vestibular hair cells

• surgery to constrict the endolymphatic sac

Perilymph Fistula (5.2)

a tear between the air-filled middle ear and the fluid-filled inner ear (oval or round window rupture)

Superior Canal Dehiscence (5.2)

rare disorder causing abnormal thinning of bone over the superior semicircular canal

What are the key symptoms and diagnostic approaches for perilymph fistula. (5.2)

• symptoms: hearing loss, tinnitus, dizziness (vertigo), nausea, unsteadiness with activity

• symptoms may be be exacerbated by sneezing, coughing, blowing nose

• tullio phenomenon: sound induced vertigo

What are the key symptoms and diagnostic approaches for superior canal dehiscence. (5.2)

• symptoms: mobile 3rd window

• sensitivity to bone-conduction

• sound-evoked eye movement

• exacerbated by high intra-oral pressure

• elevated air conduction thresholds, improved bone-conduction thresholds

Describe the treatment methods and management strategies for perilymph fistula. 
(5.2) 

• most heal on their own/ bed rest for a week

• sometimes surgery is needed to patch the fistula

Describe Ewald’s First Law. (5.3)

eye movement always occurs in plane of canal being stimulated and in direction of flow of endolymph

What is nystagmus? (5.3)

the movement of the eyes either horizontally, vertically, or in a circular direction

Why does nystagmus occur? (5.3)

When you turn your head your eyes drift to the opposite direction, maintaining your gaze. Since your eyes cannot rotate in their sockets, they will eventually rapidly jerk to the center. Jerking is caused by the VOR.

How can nystagmus be induced in the clinic? (5.3)

1. rapid head shaking 

2. dix hallpike maneuver 

3. caloric stimulation

Rapid Head Shaking (5.3)

Rapidly shaking a patients head from side to side or placement of the paitients head into a different position. 

Dix Hallpike Maneuver (5.3)

Moving the head in a specific way to elicit a vestibular response, to test for BPPV.

Caloric Stimulation (5.3)

Irrigating the external canal. This is done using warm and cool water or air. This happens in a normal system. 

What are the methods of monitoring nystagmus? (5.3)

1. Frenzel goggles

2. ENG

3. VNG

Frenzel Goggles (5.3)

• goggles that allow for clear visualization of eye movements during treatment 

• the lenses magnify the paitients eyes, which make it easier to visually detect and monitor eye movements  

ENG (5.3)

Electrodes are places around the inner/outer canthi of each eye to record changes in electrical charge as the eyes move from left to right.

VNG (5.3)

Uses infrared video which allows for a more detailed observation and analysis of eye movements.  

Explain why the fast phase of nystagmus, “beating” and the VOR essentially refer to the same thing. (5.3)

If someone is perceiving angular acceleration while at rest, then their eyes will exhibit the same behavior. The behavior is perceived as rotation followed by a rapid movement in the other direction (beating).

Know how to label fast and slow phases of nystagmus on ENG or VNG tracing. (5.3)

fast- vertical slow-slanted

Briefly describe what caloric stimulation is. (5.3)

Caloric stimulation is eliciting nystagmus through irrigation of the external ear canal. It consists of warm and cool water or air.

What does COWS mean in relation to caloric stimulation? (5.3)

C: cold to the O: opposite side

W: warm to the S: same side

Identify the basic concepts behind rotational testing. (5.3)

• rotational testing is done in a special chair that can be programmed by a computer to turn precisely to the left or right with varying angular acceleration

• results give: phase & timing, gain & amount compared to the chair

• asymmetry & difference of eye movements turning in the right and left directions

Who is rotational testing primarily used for? (5.3)

infants and toddlers

Identify the basic concepts behind computerized dynamic posturography. (5.3)

evaluates balance as each of the three systems responsible for maintaining balance are eliminated

• visual system

• somatosensory system

• vestibular system

Identify the basic concepts behind Vestibular-Evoked Myogenic Potential (VEMP). (5.3)

Provides info on the function of structures and pathways not otherwise assessed. Depends on the activation of the saccule in the peripheral vestibular system. Stimulates the ear with a very high-intensity sound. Measures changes in the tension of the sternocleidomastoid muscle or ocular muscles.

Who is VEMP primarily used for? (5.3)

diagnosing SCD

What is the percentage of americans with mild to moderate hearing loss, and how many of them use a hearing aid? (5.4)

30% use hearing aid

What is the percentage of americans with moderate to severe hearing loss, and how many of them use a hearing aid? (5.4)

moderate-severe hearing loss: 20%

using hearing aid: ½ of them

What are the specific benefits of hearing aids for individuals with moderate hearing loss ? (5.4)

greatest benefit for soft and moderate speech in quiet

What are the specific benefits of hearing aids for individuals with conductive hearing loss ? (5.4)

show more benefit in general due to attenuation component without distortion component

What are the specific benefits of hearing aids for individuals with severe to profound hearing loss ? (5.4)

soft to loud speech in favorable listening conditions

What are the specific benefits of hearing aids for individuals with mild hearing loss ? (5.4)

soft speech in quiet, some benefit from speech in noise

Rule of Thumb for the lower aidable limits based on the pure tone audiogram. (5.4)

> or = to 25 dB HL at 2000 Hz with progressively increasing thresholds with frequency (assuming bilateral HL)

What are medical conditions that require physician referral before hearing aid fitting? (5.4)

1. sudden or rapidly progressing HL

2. unilateral tinnitus or tinnitus of sudden/ recent onset

3. acute or chronic dizziness

4. asymmetrical or unusually poor word recognition scores that cannot be explained by the audiogram

5. significant air-bone gap of greater than or equal to 15 dB

6. active draingage form the ear or a history of active drainage from the ear

7. otitis externa or otitis media

8. visible congenital or traumatic deformity of the ear

9. otalgia

10. cerumen blockage greater than 25%

Define impairment related to hearing loss. (5.4)

Abnormality of a structure or function. Ex. frequency selectivity.

Define disability related to hearing loss. (5.4)

Functional consequences of hearing loss (activity limitation). Ex. inability to hear in noisy environments.

Define handicap related to hearing loss. (5.4)

Social consequences of hearing loss (participation restriction). It is not correlated with the amount of disability. Ex. changing careers due to communication difficulties

The amount of handicap is correlated with the amount of:

Perceived benefit

What is the most influential factor that determines hearing aid outcomes and why is it important to assess it? (5.4)

Motivation is largest factor influencing perceived benefit. It is important to assess because the paitients are less likely to be dissatisfied with a hearing aid purchase when you take the time to understand why the patient wants the hearing aid and what their expectations are.

How can motivation be increased in a patient? (5.4)

1. involve a family member

2. demonstrate (play everyday sounds with no amplification vs amplification so they can understand)

3. involve the patient when making decisions

How does compression technology in hearing aids work? (5.5)

Compression technology allows there to be a greater amount of amplification at soft sounds and less amplification at intense sounds. So, as sound level increases, amplification decreases.

Why is it important to restore dynamic range for individuals with hearing impairments? (5.5)

Reduced dynamic range means that hearing-impaired listeners are highly susceptible to variations in speech level.

• Soft speech is really hard to hear and needs a lot of volume

• Loud speech is much easier to hear and may need a little or no volume at all

What are the benefits and functions of digital noise reduction in hearing aids. How does it improve speech intelligibility and reduce listening effort in noisy environments? (5.5)

The benefits are that it works towards solving the SNR problem. As SNR loss increases, so does the need for higher levels of technology.NOT DONEEEE

Evaluate the effectiveness of directional microphones in hearing aids for solving the signal-to-noise ratio problem and enhancing speech intelligibility in noisy settings. (5.5)

It improves speech intelligibility through having multiple microphones. The speakers produce a cartiod pattern, suppressing background noise.

Compare the advantages of hearing aids with wireless connectivity to those with only directional microphones. (5.5)

Wireless Connectivity: remote control, connects to phones, streaming sound options, automate routine tasks, biomarkers that can be used to track health

Directional Microphones: better with SNR

What is the role of environmental classifiers in hearing aids? (including how they they contribute to automatic processing for improved speech clairty and comfort in noise) (5.5)

Classifiers sample the listening environment and generate probabilities for each of the options in the automatic program. The hearing aid switches to the option with the highest probability. COME BACK AUTOMATIC PROCESSING

What are the limitations of acoustic classifiers? (5.5)

They are limited because different engineers have different philosophies in what aspects of the signal should be prioritized. They can also fail to accurately capture the listening environment, the user’s listening needs, and their listening intents.

Give examples of how AI, including machine learning and deep neural networks, are integrated into hearing aid technology for enhance performance. (5.5)

A typical hearing aid could never be perfect for every person in every situation. Each person is in different situations and has different intents in those situations. Machine learning allows users to convert the degree of preference for a given listening environment into 13 gain adjustments in 3 bands.

What is the potential impact and advantages of bluetooth 5.2 technology in hearing aids? (5.5)

• hearing aids could direct connect to devices, to take calls and stream audio

• audio quality will be much better than current loop systems

• no prior pairing required

• public assistive listening will become ubiquitous

• could be mandated in public places

• could be in venues, private homes, shops, etc.

How do biosensors and inertial sensors in hearing aids contribute to overall health monitoring, including fall detection and physical activity tracking? (5.5)

• can detect falls

• can detect other health stats such as blood pressure, glucose & oxygen levels, temp

• allows use to tap the hearing aid and awaken a smart assistant, and nod or shake their head to respond to it