Sensory and Perception Flashcards
What is the general effect of aging on the senses?
Decline in acuity in all senses
Visual acuity declines because of
- 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
The Retina
contains rods, cones, and nerve pathways
- Rods: for night vision; eye contains around 125 million
- Cones: for day & colour vision; eye contains around 6 million
Name some normal age-related changes in vision.
Thicker, less curved cornea; smaller anterior chamber; faded iris color; decreased pupil diameter; less elastic, denser, yellower lens (presbyopia); more liquid vitreous humor; narrower retinal vessels
Name some common vision disorders (pathological changes) that increase with age.
Cataracts, glaucoma, macular degeneration
What are cataracts?
Lens becomes cloudy or develops opaque areas that block light, usually associated with blurred vision.
*Common in older adults
What is the main cause of glaucoma?
Inadequate drainage of aqueous humour, damaging optic nerve
- leading cause of blindness
- Can be gradual (open-angle) or sudden (closed-angle)
Macular Degeneration - Affected Area and Result
Tissue in the macula (center of vision) deteriorates, causing a blind spot in the center of vision. A frequent cause of vision loss in older adults
Implications of visual changes
These changes can impact refraction, accommodation, light admission, and light/dark adaptation, leading to decreased visual acuity, increased sensitivity to glare, and a higher visual threshold
Age-Related Changes in the Outer Ear
The pinna loses flexibility, and hairs become stiffer
Age-Related Changes in the Middle Ear
Calcification of the ossicles, and the tympanic, oval, and round window membranes become less flexible. Lessened efficiency of the acoustic reflex
What are the three main types of hearing impairment?
Conductive, sensorineural, mixed
Conductive hearing impairment
something is interfering with transmission of sound through the outer or middle ear (e.g., impacted cerumen or ear wax, arthritic changes in ossicles)
Sensorineural hearing impairment
disorders of inner ear affecting transmission of sound to auditory receptors or through auditory pathways (e.g., presbycusis)
Mixed hearing impairment
both conductive and sensorineural
Presbycusis
Hearing loss that gradually occurs in most individuals as they grow older, usually in both ears and greater for high-pitched sounds. Common in older adults
Types of presbycusis
Sensory: degeneration of organ of Corti
Neural: loss of neurons of cochlea & higher auditory pathway
Strial/metabolic: atrophy of fibrous vascular cochlear tissue
Mechanical: affects basilar membrane of cochlea
Tinnitus
Ringing, roaring, clicking, or hissing sound in the ears that can interfere with daily life. Can be caused by hearing loss, loud noise, medications, allergies, tumors, and other medical issues
Otosclerosis
bilateral progressive hearing impairment caused by abnormal bone formation; occurs in oval window and eventually immobilizes the stapes
Otosclerosis Interventions
Hearing aids
Surgery: stapedectomy (removal of the stapes bone; prosthesis is substituted for the non-functioning stapes bone.)
Presbycusis and Speech Perception - Impact on Language Comprehension
Reduced high-frequency auditory acuity means some sounds are affected more, leading to difficulty discriminating words with high-frequency sounds (lexical discrimination)
Sensory Acuity and Driving - Visual Issues
Trouble seeing may involve difficulty with peripheral movement, reading signs, night vision, and be impacted by eye diseases
Sensory Acuity and Driving - Auditory Issues
Trouble hearing may involve not noticing horns/sirens, difficulty with background noise, slower responses to sounds, and miscommunication with passengers or GPS devices
