Sensory Changes in Aging Adults

Pamela Z. Cacchione, PhD, RN, BCGNP
Background
The majority of older adults will experience some changes in their sensory capacity (vision, hearing, smell, taste and peripheral sensation) as a normal part of aging. Some sensory changes, for example changes in hearing, can severely impact an older person’s communication skills. This section on sensory changes addresses common changes seen with advancing age and the disease states and injury that occurs more frequently in aging and that impact the sensory system.

Vision
30% of those over age 65 have some level of visual impairment. Cataracts are the 5th most common chronic condition in adults over age 75.
Definitions

• Normal vision: Visual Acuity of 20/20 or better
• Visually Impaired: Visual Acuity of 20/50 or worse
• Legally Blind: Best corrected vision of 20/200 or worse
• Totally Blind: No light perception

Vision Changes common in older adults Presbyopia: A loss of elasticity in the lens of eye leading to a decrease in the eyes ability to change the shape of the lens to focus on near objects such as fine print and decreased ability to adapt to light.

• Thickening of the lens with loss of elasticity
• Decreased contrast sensitivity
• Delayed recovery from glare

Diseases that alter vision seen more frequently as people age

• Cataracts: Clouding of the crystalline lens presents as painless, progressive loss of vision can be unilateral or bilateral.
• Macular Degeneration: The most common cause of legal blindness in the elderly. The development of drusen deposits in the retinal pigmented epithelium leading cause of central vision loss in older adults. More common in fair haired blue eyed individuals. Other risk factors include smoking and excessive sunlight exposure. There are wet and dry forms of macular degeneration.
• Glaucoma: A potentially serious form of eye disease. The majority of cases of glaucoma are Open angle glaucoma (95%). Increased intraocular pressure causing atrophy and cupping of the optic nerve head causing visual field deficits that can progress to blindness. Vision changes include loss of peripheral vision, intolerance to glare, decreased perception of contrast and decreased ability to adapt to the dark.
• Diabetic Retinopathy: End organ damage from diabetes causing retinopathy and spotty vision. Risk can be reduced by tight blood sugar control. Starts as nonproliferative and progresses to proliferative that should be treated with laser photocoagulation.
• Hypertensive Retinopathy: End organ damage from poorly controlled hypertension causing background and eventual proliferative retinopathy. Usually treated with laser photocoagulation and tight blood pressure control.
• Temporal Arteritis: Autoimmune disorder that causes inflammation of the temporal artery. It presents as malaise, scalp tenderness, unilateral temporal headache, jaw claudication, and sudden vision loss (usually unilateral). This vision loss is a medical emergency but is potentially reversible if identified immediately. The client should see an ophthalmologist, or go to the emergency room immediately if symptoms develop.
• Detached Retina: Can occur in patients with cataracts or recent cataract surgery, trauma or be spontaneous. Presents as a curtain coming down across vision. Should see an ophthalmologist or proceed to the emergency room immediately.

Implication of Vision Change

• Impact on Safety
  • Inability to read medication lables
  • Difficulty navigating stairs of curbs
  • Difficulty driving
  • Crossing streets
• Impact on Quality of Life
  • Reduces ability to remain independent
  • Difficulty or unable to read
• Falls
  

Hearing
Hearing loss is the 3^rd leading chronic condition affecting adults over 75 years of age.
Definitions

• Hearing Impaired: Defined in Decibels (dB) or level of loudness
  • Mild hearing impairment 20 to 40 dB
  • Moderate 40 to 55 dB
  • Moderately severe 55 to 70 dB
  • Severe hearing impairment 70 to 90 dB
  • Greater than 90 dB is profound deafness, unable to hear sound

Hearing Changes common in older adults

• Presbycusis: Loss of high frequency, sensorineural hearing loss. Has a gradual onset is progressive and is bilateral. Due to gradual loss of hair cells, and fibrous changes in the small blood vessels that supply the cochlea. Difficulty hearing high pitched sounds such as s, z, sh, and ch. Background noise further aggravates hearing deficit.
• Conductive hearing loss: Involves the outer and or middle ear. Causes of conductive hearing impairment include: cerumen impactions or foreign bodies; ruptured eardrum, otitis media, and otosclerosis.
• Sensorineural hearing loss: involves damage to the inner ear, the cochlea, or the fibers of the eighth cranial nerve. Causes of sensorineural hearing loss include: hereditary causes, viral or bacterial infections, trauma, tumors, noise exposure, cardiovascular conditions, ototoxic drugs and Meniere’s disease.

Diseases that alter hearing seen more frequently as people age

• Central auditory processing disorder: An uncommon disorder that includes an inability to process incoming signals and is often found in stroke patients and older adults with Alzheimer Dementia. The person’s hearing is intact but their ability to process the sound is impaired.
• Tinnitis: Ringing in the ears may fluctuate can be due to damage to the hair receptors of the cochlear nerve and age related changes in the organs of hearing and balance. Patients with tinnitis should be referred to ENT
• Meniere’s Disease: characterized by fluctuating hearing loss, dizziness and tinnitus. Possible causes of Meniere’s disease include: hypothyroidism, diabetes and neurosyphillis
  

Implications of Hearing Changes

• Impact on quality of life

Impairs ability to communicate with others

• Adds to social isolation
• Leads to depression or low self-esteem
• Safety issues
  • Unable to hear instructions, such as how to take medications,
  • Unable to hear car coming when crossing the road, horns honking
  • Unable to hear phone or doorbell ringing or knocking at the door (if emergency occurs may be unaware)

Smell and Taste
The sense of smell and ability to identify odors decreases due to normal changes in aging. This can be problematic for safety reasons. An inability to smell smoke for instance could put an older adult at risk.
Changes in smell and taste common to older adults

• Common changes in smell include a decline in the sensitivity to airborne chemical stimuli with aging.
• Common changes in taste include a decreased ability to detect foods that are sweet. Most changes in taste are thought to occur due to decreased sense of smell, medications, diseases and tobacco use.

Diseases that alter smell and taste seen more frequently as people age

• Burning Mouth Syndrome : This is a sensation that one’s tongue is tingling or burning. There may be several contributing factors: Vitamin B deficiencies, local trauma, gastrointestinal disorders causing reflux, allergies, salivary dysfunction and diabetes.

Implications of Taste and Smell Changes

• Inability to smell
  • Effects quality of life — Scents such as smell of Christmas tree, flowers or coffee brewing may not be detectable. Diminished taste of favorite foods or beverages.
  • Nutritional decline – inability to smell food aromas may reduce nutritional intake
  • Safety hazard — inability to smell smoke in a fire or a gas leak.

• Decreased sense of taste
  • May result in inability to recognize spoiled food resulting in nausea, vomiting or infectious diarrhea.

Peripheral Sensation
Peripheral neuropathy is one of the most common neurological disorders encountered in a general medical practice with estimates of 2% to 7% of all patient populations having symptoms of neuropathy (Smith and Singleton, 2004). An assessment of 894 participants in the Women’s Health and Aging Study indicated that 58% of women showed evidence of neuropathy by age 65 (Vinik, 2004).
Changes in peripheral sensation common to older adults

• Peripheral nerve function that controls the sense of touch declines slightly with age.
• Two-point discrimination and vibratory sense both decrease with age.
• The ability to perceive painful stimuli is preserved in aging. However, there may be a slowed reaction time for pulling away from painful stimuli with aging.

Diseases that alter peripheral sensation seen more frequently as people age

• Peripheral neuropathy: Nerve pain in the distal extremities related to nerve damage from circulatory problems or vitamin deficiencies. Common vitamin deficiencies which impact peripheral nerves include B 6, B 12 and Folate.
  Diabetic neuropathy: End organ damage to the peripheral nerves from microvascular changes which occur with diabetes. Often leads to loss of sensation in the feet of diabetics leading to undetected trauma to the extremities which can lead to refractory infections due to poor vascular supply to the extremity. It is extremely important to teach diabetics and patients with peripheral neuropathy to provide special care to their feet.
• Phantom Limb pain: The experience of pain that can range from dull ache to crushing pain where an amputated limb once was. The sensory cortex of the brain has influence in this mechanism. This pain is often chronic and requires special interventions to control and manage the pain including electronic prosthetics, analgesics, and psychosocial support
• Acute Sensory Loss: May be due to a stroke, acute nerve entrapment in the spine or compartment syndrome due to trauma to a limb. Will present with acute onset of numbness, tingling or lack of sensation and function in the effected extremity.

Implications of Peripheral Sensation Changes

• Falls – due to inability to recognize position sense or inability to ascertain where feet are on floor.
• Calluses or serious foot lesions.