6 - sensory and perception

Question 1

Overall, there is a general decline in acuity in all senses with age, what are these senses? (6)

Answer 1

1) Vision
2) Audition (hearing)
3) Somatosensory (touch)
→ changes in stimulation to touch (loss of receptors)
4) Gustatory (taste)
5) Olfactory (smell)
6) Vestibular (balance)
→ joint stiffness, spatial orientation

Question 2

Visual acuity declines because of…

Answer 2

→ Changes in the visual system that occur with normal aging
→ Can also be affected by several disorders that increase in prevalence with age
→ E.g., Macular degeneration, cataracts

Question 3

Name the parts of the eye and their general rolls. (8)

Answer 3

1) Sclera: White of the eye (outer)
2) Cornea: Surface of the eyeball
→ provides structure, support and protection for the eye
3) Anterior chamber: Space between cornea and lens; filled with aqueous humor
4) Iris: Changes pupil size
5) Lens: Changes shape to focus light rays on retina
6) Vitreous humor: Maintains shape of the eyeball
7) Retina: Contains rods and cones
- Rods: for night vision; eye contains around 125 million
→ does not detect colour
→ responsible for vision in dim light
- Cones: for day & colour vision; eye contains around 6 million
→ visual acuity, sharpness and more detailed vision
→ convert into electrical signals, processed through several layers of neurons within the retina before they get transmitted to the brain
8) Optic nerve: Leaves the eye via the optic disk

Question 4

True or false: The cornea becomes thicker and less curved with age.

Answer 4

True: This is a normal age-related change in vision

Question 5

What is arcus senilis when talking about normal age-related change in vision?

Answer 5

• A gray ring that forms around the edge of the cornea
  → Caused by fat lipid deposits deep in the edge of the cornea
  → It does not affect vision, nor does it require treatment

Question 6

True or false: The anterior chamber gets larger with age, this is a normal age-related change in vision.

Answer 6

False: The anterior chamber gets smaller with age, often due to the thickening of the lens.

Question 7

Aqueous humor may drain inadequately, causing increased ___ ___ and possibly ___.

Answer 7

Intraocular pressure; glaucoma
→ The aqueous humor helps to maintain shape of the eye
→ elevated pressure inside the eye can damage the optic nerve, potentially causing glaucoma
- This is a normal age-related change in vision.

Question 8

A normal age-related change in vision is that the iris colour ___ and pupil diameter ___.

Answer 8

Fades; decreases

Question 9

What happens to the lens with normal age-related change?

Answer 9

→ Become less elastic, denser, and yellower
→ This causes changes in color vision
→ Likelihood of presbyopia (farsightedness) increases

Question 10

What happens to the vitreous humous with normal age-related change?

Answer 10

• Vitreous humour becomes more liquid. Loose cells may cause shadows (floaters)
  → cells that were once attached start to float around, which may cause shadows
  → helps to maintain the shape of the eye

Question 11

What happens to the retina with age-related change?

Answer 11

→ Vessels & capillaries narrow
→ Loss & change in chemical sensitivity of rods & cones
→ becomes less able to process visual information

Question 12

What are the implications of age related changes in vision?

Answer 12

• Decreased visual acuity due to:
  → Changes in refraction by cornea & lens; Decreased accommodation ability (the eye becomes less able to be flexible to changes and to different white lights and colour); Less light admitted due to smaller pupils; Reduced number of rods & cones; Decreased light/dark adaptation (decrease in ability to focus on depth, require glasses for reading)
• Higher visual threshold (minimum light required to stimulate receptors)
  → due to decrease in rods and cones; more light is required to stimulate your receptors
• Increased sensitivity to glare
  → makes it very troublesome when driving
• Increased critical flicker fusion (rate at which consecutive visual stimuli can be perceived as separate)
  → if you can’t see consecutive visual stimuli, any type of changes with cars swerving in and out or breaking, you’ll have a slower reaction time

Question 13

Name the vision disorders that increase in prevalence with age (3)

Answer 13

1) Cataracts
2) Glaucoma
3) Macular degeneration

Question 14

Explain what cataracts is and how it develops.

Answer 14

• Develops slowly and can affect one eye or both
• Lens becomes cloudy or develops opaque areas that block light from passing through (opacities)
• Usually associated with blurred vision
  → faded colours, halos around bright lights, trouble seeing at night
• Around 50% of Americans age 80+ have cataracts or have had cataract surgery

Question 15

Explain what glaucoma is and how it develops.

Answer 15

• Glaucoma is a leading cause of blindness
• It is usually caused by inadequate drainage of aqueous humour, leading to damage to the optic nerve
  → too much liquid in the aqueous humour
  → leads to loss of nerve tissue, irreversible vision loss and potential blindness if not detected and treated early
• May occur gradually (open-angle glaucoma) or quite suddenly (closed-angle glaucoma)
  → open-angle: elevated pressure caused by a buildup of fluid in the eye
  → more common form
  → could be due to vitreous humour or aqueous humour

Question 16

Explain what macular degeneration is and how it develops.

Answer 16

• Tissue in the macula (the part of the retina responsible for center of visual field) deteriorates; a blind spot forms in the center of vision
  → because of yellow deposits form under the retina
  → larger deposits develop over time and blood vessels grow and eventually leak
  → when they grow and leak, the blood damages the retina
• the peripheral stays in tact but the center field of view is what is impacted and lost
• One of the most frequent causes of vision loss in people aged 60
• usually irreversible but the extent of the vision loss may be reduced if caught early

Question 17

What are some Canadian estimates of blindness and causes of blindness?

Answer 17

• ~1.5 million Canadians identify themselves as having a sight loss
• ~5.59 million more have an eye disease that could cause sight loss
• The leading causes of blindness in Canada are:
  1) Cataracts: 3,541,000 people
  2) Age-related macular degeneration: 1,574,000 people
  3) Glaucoma: 294,600 people
  4) Diabetic retinopathy: 749,800 people
  → diabetes complication that affects the eyes
  → caused by damage to the blood vessel, specifically light sensitive tissue at the back of the eye (retina)
  → at first, it may cause no symptoms or only mild vision symptoms, but then blurred vision, impairment of colour and dark strings that float in field of vision start to come in

Question 18

Auditory acuity is affected because of…

Answer 18

→ Normal changes with age (e.g., reduction in flexibility of parts of the auditory system)
→ Increased risk of disorders that result in hearing loss (e.g., tinnitus)

Question 19

Name the parts of the ear and their general role.

Answer 19

1) Outer ear
- Pinna: captures the sound
- Auditory canal: funnels the sound to the eardrum
2) Middle ear
- Tympanic membrane (eardrum)
→ vibrates with the sound
- Eustachian tubes (from the throat)
→ connect to the throat to equalize pressure
- Ossicles
→ tiny bones that amplify sound vibrations to the inner ear: (malleus = hammer, incus = anvil, stapes = stirrup)

Question 20

How does sound travel through the ear?

Answer 20

• Sound from external environment is channeled by the pinna and the external auditory canal, to the tympanic membrane, and the pinna will intensify the sound, especially in the 250herts- 4 kilohertz range of human speech

Question 21

True or false: As we age, the pinna loses flexibility and the hair becomes stiffer.

Answer 21

True

Question 22

True or false: The tympanic membrane becomes more flexible with age.

Answer 22

False; it becomes less flexible with age

Question 23

Elaborate on the ossicles and their role.

Answer 23

• Transmit sound vibrations from eardrum to oval window
  → Oval window make fluids in inner ear vibrate
  → This stimulates auditory receptors
• Tympanic reflex: muscles pull ossicles away from membranes when a loud noise occurs (to protect the ear)
  → the tympanic cavity is like a protective membrane against loud sounds
  → as we get older, the ossicles become calcified, which makes it much harder to transmit sound vibrations

Question 24

Elaborate on the labyrinth and its role.

Answer 24

• Has 2 parts:
  1) Bony labyrinth (top left)
  → Vestibule
  → Cochlea (organ of Corti, containing hair cells for hearing)
  → Semicircular canals (for balance)
  2) Membranous labyrinth
  → Interconnecting membranous ducts within bony labyrinth

Question 25

Explain how sound passes through the ear in respect to the ossicles and labyrinth.

Answer 25

The outer ear collects the sound and directs it through the auditory canal, to the tympanic membrane in the middle ear, where sound vibrations are amplified by the ossicles, these vibrations travel to the oval window, stimulating the fluid movements in the bony labyrinth, particularly in the cochlea (hair cells convert sound into signals), and the semicircular canals and the vestibule help maintain balance

Question 26

Elaborate on the fluids that the ossicles vibrate.

Answer 26

• A fluid called perilymph fills the space between the bony and membranous labyrinths
• Fluid inside the membranous labyrinth is called endolymph
• These fluids play an important role in the transmission of sound waves and the maintenance of body balance
  → disorders like meniere’s disease (disorder of the inner ear) disrupt this delicate system leading to vertigo or dizziness and hearing loss; typically only affects one ear

Question 27

What are some age-related changes in hearing?

Answer 27

→ The pinna loses flexibility and hairs become stiffer
→ Calcification of the ossicles
→ Tympanic, oval window, and round window membranes become less flexible
→ Lessened efficiency of the acoustic reflex; involuntary muscle contraction that occurs in the middle ear in response to stimuli, particularly loud stimuli
→ around 60% of those over 65 suffer from hearing impairments

Question 28

What are the 3 types of hearing impairments?

Answer 28

1) Conductive: something is interfering with transmission of sound through the outer or middle ear (e.g., impacted cerumen or ear wax, arthritic changes in ossicles) (sound waves not traveling efficiently from the outside)
2) Sensorineural: disorders of inner ear affecting transmission of sound to auditory receptors or through auditory (nerve) pathways (e.g., presbycusis)
3) Mixed: both conductive and sensorineural

Question 29

Elaborate on conductive hearing impairment. What are its symptoms? How is it treated?

Answer 29

• Something is interfering with transmission of sound through the outer or middle ear (e.g., impacted cerumen or ear wax, arthritic changes in ossicles) (sound waves not traveling efficiently from the outside)
• some types of conductive hearing loss can be corrected with hearing aids, or treated medically or surgically (medical and surgical may not fully reverse the conductive loss though)
  → the most effective solution is hearing aids because you’re not going under the knife, and it provides just as much benefits
• some symptoms: difficulty in hearing speech, a sense that your own voice sounds different, easier to hear out of one ear than the other, sensation of pain through one ear or both ears
• besides aging, there are other reasons for hearing loss; fluid build up in the ear, allergies, infections, etc.

Question 30

Elaborate on sensorineural hearing impairment; what is affected? what are its treatments?

Answer 30

• Disorders of inner ear affecting transmission of sound to auditory receptors or through auditory (nerve) pathways (e.g., presbycusis)
• hearing loss due to nerve damage
  → can be anywhere along the nerve pathways that connect the inner ear to the brain; outer and middle ear are functioning properly, but still some sounds aren’t being interpreted properly and may not be reaching the brain at all
• difficulty hearing soft or faint sounds, especially in a crowded or noisy environment
  → beyond aging, a lot of it is contributed to loud noise as well; sometimes it can be hereditary
• Treatments here are similar to conductive; hearing aids, or specific types of cochlear implants
  → this condition also incorporates damage to nerve endings, there could be specific bone issues along the neural pathways that may need surgery (this is in extreme cases)

Question 31

Chances of developing sensorineural impairment increase drastically when you’re __ or older.

Answer 31

55

Question 32

What are the risk factors of hearing loss?

Answer 32

• Aging, heredity
• Occupational noises: p.ex farming, construction/factory work
  → likelihood of developing a hearing issue becomes much higher
• Recreational noises: p.ex; explosive noises, such as from firearms and fireworks; snowmobiling, motorcycling or listening to loud music
• Some medications & illnesses (e.g., meningitis)

Question 33

What are the 3 ranges of decibels?

Answer 33

1) Safe range: 30 - 70
- Whisper; normal conversation; washing machine
2) Risk range: 85 - 110
- heavy city traffic; hair dryer; motorcycle; snowmobile; chain saw; rock concert; hand drill; power lawn mower
3) Injury range: 120 - 180
- ambulance siren; jet engine at takeoff (140 db, i.e., pain threshold); 12-guage shotgun blast; rocket launch

Question 34

What are the implications of hearing loss?

Answer 34

→ Difficulty in distinguishing spoken words
→ Personality changes
→ Hearing aids/cochlear implants for profoundly deaf
→ the longer you wait to resolve a hearing issue, the more problematic it becomes

Question 35

What is presbycusis?

Answer 35

• Hearing loss that gradually occurs in most individuals as they grow older
  → normal age-related hearing loss
• Usually occurs in both ears
• Usually greater for high-pitched sounds
• if combined with an occupation which exposes you to loud noises all the time, you would probably have this at a much earlier age, or even another hearing disorder earlier on as well

Question 36

About __-__ percent of adults aged 65- 75, and __-__ percent of people aged 75+ have a hearing loss.

Answer 36

30-35; 40-50

Question 37

Male hearing loss typically robs the ears of ___ frequency hearing first, whereas for women, hearing loss typically robs the ears of ___ frequency hearing first.

Answer 37

High; low
→ which is why men have a harder time later in life understanding consonant sounds that contain higher pitches; and women struggle to understand deep rounder sounds of vowels

Question 38

What are the 4 types of presbycusis?

Answer 38

1) Sensory
2) Neural
3) Strial/metabolic
4) Mechanical

Question 39

Explain the sensory type of presbycusis.

Answer 39

• Sensory: degeneration of organ of Corti
  → atrophy or deterioration with the outer hair cells in the Corti; structure in the cochlea that produces nerve impulses in response to sound vibration
  → base of the cochlea affected first, and the condition slowly progress towards the inner tip of the cochlea
  → sharp drop in the ears’ ability to perceive high frequency sounds (alarms, birds p.ex)
  → speech discrimination remains, but high frequency sound range is the one that goes

Question 40

Explain the neural type of prebycusis.

Answer 40

• Neural: loss of neurons of cochlea & higher auditory pathway
  → atrophy of nerve cells in the cochlea and the auditory pathways to the brain
  → in order to be prescribed as having this condition (criteria for this diagnosis), you must have a loss of 50% or more of the cochlear neurons
  → people with this specific infliction have a severed decrease in speech discrimination compared to the level of their hearing loss, tones of all frequency are affected
  → damage ranges from synaptic structures between the hair cells and the dendrites of the auditory nerve cells or fibres

Question 41

Explain the strial/metabolic type of presbycusis.

Answer 41

• Strial/metabolic: atrophy of fibrous vascular cochlear tissue
  → atrophy of the stria vascularis; this component provides the blood supply to the inner ear and maintains the chemical and bioelectric balance of the cochlea
  → results in hearing loss; flat hearing curve meaning high and low frequencies are all affected because the entire cochlea is affected
  → speech discrimination however is preserved in this condition

Question 42

Explain the mechanical type of presbycusis.

Answer 42

• Mechanical: affects basilar membrane of cochlea
  → degenerative thickening and stiffening of the basilar membrane
  → correlates with sensorineural hearing loss that is slowly progressive
  → speech discrimination is essentially on par with the person’s level of hearing
  → p.ex: if you’re hard of hearing, you’re gonna have a hard time with speech discrimination

Question 43

What is tinnitus? What are its causes?

Answer 43

• > 360,000 Canadians have tinnitus in an annoying form; for ~150,000, these noises seriously impair their quality of life
• Ringing, roaring, clicking, or hissing sound in the ears that can be severe enough to interfere with ADLs (even though there is no outside noise causing it)
  → seriously impairs quality of life
• Causes:
  → Hearing loss
  → Exposure to loud noise
  → More than 200 medications can cause tinnitus
  → Allergies, tumors, and problems in the heart and blood vessels, jaws, and neck can cause tinnitus

Question 44

What is otosclerosis? What are its interventions?

Answer 44

• Otosclerosis: bilateral progressive hearing impairment caused by abnormal bone formation; occurs in oval window and eventually immobilizes the stapes
  → stapes is unable to vibrate, the sound is then unable to travel through the ear and hearing thus becomes impaired
  → hearing loss is the most frequently reported symptom for this condition, typically starts in one ear and moves to the other; this loss happens gradually
  → most people first notice that they’re unable to hear low pitched sounds (can’t hear a whisper)
  → can also experience dizziness, balance problems or tinnitus, but how or why this happens is unclear
• Interventions:
  → Hearing aids; Surgery: stapedectomy (removal of the stapes bone; prosthesis is substituted for the non-functioning stapes bone)

Question 45

Many older adults have difficulty with speech perception when…

Answer 45

• When the speech is accompanied by noise, especially when the speech rate is fast even without hearing loss
  → the reason for this difficulty with fast speech is because as you get older a lot of your processes (not just cognitive, but also perceptual) get slower, so older adults need longer gaps between words than young adults (BUT still does not excuse elderspeak)

Question 46

Speech perception declines in aging due to…

Answer 46

• Due to both sensory problems (hearing loss) and cognitive changes (e.g., processing speed, inhibitory function)
• Declines in speech perception are particularly marked when background noise is present (e.g., at a party)
  → in older adults there is a decreased hearing sensitivity and reduced attention

Question 47

What is sensory integration when talking about hearing function and speech perception?

Answer 47

• Adding visual information (i.e., seeing the speaker) aids speech understanding
  → This effect is known as “visual enhancement” and occurs for both younger and older adults
  → Thus, allowing a hearing-impaired listener to watch the speaker’s mouth is an important way to improve their understanding because they can surmise a lot of information, not just from the words but from the person speaking

Question 48

How does presbycusis influence speech perception?

Answer 48

• Hearing loss is more severe at higher frequencies (presbycusis)
• Declines in auditory acuity result in impaired language comprehension in many older adults
• Reduced high-frequency auditory acuity means that some sounds are affected more than others
• To understand why, let’s look at a spectrogram..
• the speech of a typical adult male wil range from 85 - 180 hertz, and that of a typical adult female will have 165 - 255 hertz
  → the more db that are needed for you to hear properly, that’s how we categorize how bad the hearing loss is

Question 49

What are the implications of difficulty with hearing function and speech perception?

Answer 49

• This leads to difficulty discriminating words with high-frequency sounds
  → especially if you have presbycusis
• Can lead to difficulty with lexical discrimination refers to uniquely selecting a single word as the input
  → e.g., “sight” vs. “fight”
  → people with presbycusis may not be able to differentiate between these 2 words

Question 50

True or false: Not every older adult knows that they have difficulty with their hearing or their speech.

Answer 50

True

Question 51

__% of older adult drivers have some form of mild cognitive impairment. Yet, up to __% of older adults with dementia continue to drive.

Answer 51

60; 30

Question 52

How does sensory acuity play into driving?

Answer 52

• Driving is a key aspect of independence for older adults, which is why they will typically fight you if you try to remove that aspect from their lives
  → removing it entirely though is a very serious decision because it removes their independence and social lives to a certain extent
• Older adults are at an increased risk of crashes per mile driven
• Older adults are more susceptible to injury from an accident

Question 53

Trouble seeing while driving may be related to…

Answer 53

• Being harder to see movement in your periphery
  → p.ex: if a child is running in from the side of the street, they may have a delayed reaction to it
• Taking longer to read a street sign or recognize familiar places
• Difficulty seeing things clearly at night
  → glare from oncoming headlights p.ex
• Eye diseases such as glaucoma, cataracts, or macular degeneration can impact general sight

Question 54

Trouble hearing while driving may be related to…

Answer 54

• Not noticing horns, sirens, or even noises from your car
• Difficulty discriminating important sounds from background noise
• Slower responses to sounds (e.g., emergency vehicles or honking horns)
  → this is very problematic because these indicate problems meaning needing to pull over, there could be sounds coming from the car which indicate trouble which they can’t hear
  → can mask critical auditory cues from outside the car
  → may need an added visual cue to make a judgment call to pull over with sirens
• Miscommunication with passengers or GPS devices
  → misinterpreting important information

Question 55

Not all changes in driving ability are attributable to sensory-perceptual changes; what are some other factors that could play a role in declining driving ability?

Answer 55

→ muscle function, cognitive declines, sleep issues, medical condition or on medication
- other areas of everyday life influenced by these declines
→ cooking, home safety (leaving the stove on p.ex or not hearing an alarm)

Question 56

What are some ways we can re-engineer the world to help older adults deal with declines in sensory acuity?

Answer 56

→ more clear signs with contrast for them to read, making devices that provide aid can be very helpful or even reducing the price of aid devices