Vestibular, hearing, & vision disorders

Question 1

Types of hearing loss

Answer 1

1. Conductive
2. Sensorineural hearing loss
3. Mixed hearing loss

Question 2

Conductive hearing loss

Answer 2

• when sound is not conducted efficiently through the outer ear canal to the eardrums, bones (ossicles) of middle ears
• involves a reduction in sound level or the ability to hear faint sounds
• can often be corrected medically or surgically

Question 3

Sensorineural hearing loss

Answer 3

Damage to the inner ear (cochlea), the nerve pathways from the inner ear to the brain

• generally cannot ge medically or surgically corrected
• most common type of permanent hearing loss
• auditory brain stem response (ABR) detects sensorineural hearing loss using electrodes placed on scalp

Question 4

Hearing tests

Answer 4

1. Whispered speech test: the tester stands 1 ft behind and whispers
2. Pure tone audio entry: audiometer plays series of tones into headphones that vary in pitch and loudness
3. Tuning fork: tester strikes tuning fork which vibrates and produces a tone. Assesses how well sounds moves through the ear
4. Speech reception and word recognition measures ability to hear and understand normal conversation. Repeat a series of simple words spoken with different loudness
5. Otoacoustiv emissions (OAE): screens newborns for hearing probs microphone is placed in ear canal, sound introduced, and microphone detects the inner ear’s response to sound

Question 5

Mixed hearing loss

Answer 5

• conductive hearing loss occurs with sensorineural (SNHL)

- may be damage in the outer or middle ear and in the inner ear or auditory nerve

Question 6

Vestibular system

Answer 6

Processes sensory information involved in controlling balance and eye movement

• etiology: trauma, infection, idiopathic, tumors, CVA, medications
• Tx: epley maneuver (moving side to side)

Question 7

Vision

Answer 7

• 32 centers in the cortex involved in vision
• over half of the brain is wired for vision
  1. Where am I?
  2. Where is my world?
  3. Who and what is in my world?
  4. Perception and interaciton with my world

Question 8

Rods vs cones

Answer 8

1. Rods:
   - night vision - low visual activity - no color perception - mostly in the periphery
2. Cones:
   - day vision - high visual activity - color vision - mostly in/near focus

Question 9

Cataracts

Answer 9

Cloudy areas that develop in the eye lens

- if they become large or thick, cataracts can usually be removed by surgery

Question 10

Glaucoma

Answer 10

There is a typical and progressive deterioration of the optic nerve due to increased pressure inside the eyeball

• often associated with an increased pressure of the eye
• this increased pressure is associated with damage to the optic nerve; this is called primary open angle glaucoma

Question 11

Macular degeneration

Answer 11

The macula (retina) gradually deteriorates, which impairs central vision. Peripheral visions remains unchanged

• can severely impair vision
• no cure for macular degeneration
• treated with vitamins, laser therapy, medications, and vision aids

Question 12

Vision tests

Answer 12

1. Visual activity: sharpness. Measures eye’s ability to see details at near and far distances
2. Refraction test: shows level of refractive error and helps prescribe glasses or contact lenses
3. Visual field test: checks for gaps in peripheral vision. Complete visual field is entire are seen when gaze is fixed in one direction
4. Color vision tests: checks ability to distinguish colors. Screens for color blindness with suspected retinal or optic nerve disease or with family history of color blindness