Chapter 42

Sensory System

Sensation, Perception, and Cognition

• Sensation– Ability to receive and process stimuli through

sensory organs

• Perception– Ability to experience, recognize, organize, and

interpret sensory stimuli

• Cognition– Intellectual ability to think

(continued)

Anatomy and Physiology Review

• Central and peripheral nervous systems act to accomplish three purposes:1. Collect stimuli from receptors at end of

peripheral nerves

2. Transport stimuli to brain

3. Conduct responses to stimuli from brain to responsive motor centers in body

(continued)

Anatomy and Physiology Review

• Sensation and perception consists of afferent and efferent nerve pathways

• Cognition includes memory, affect, judgment, perception, and language

Assessment

• Focuses specifically on client’s ability to:– Hear– See– Taste– Smell– Touch

Disorientation

• Mentally confused state

• Person’s awareness of time, place, self, and/or situation impaired

Sensory Disorders

• Change in perception of sensory stimuli

• Can affect all five senses

• Sensory deprivation– State of reduced sensory input from internal

or external environment

• Sensory overload– State of excessive and sustained multi-

sensory stimulation

(continued)

Eye Anatomy

Eye Anatomy

Anterior Parts of the Eye

http://upload.wikimedia.org/wikipedia/en/3/3c/Snellen.svg

Impaired Vision

• Blindness– Central visual acuity 20/200 or less with

corrective lenses

• Partially sighted– Visual acuity between 20/70 and 20/200 in

better eye with glasses

• Many visual aids available

Refractive Errors

• Myopia– Nearsightedness

• Hyperopia– Farsightedness

• Astigmatism– Asymmetric focus of light rays on retina

(continued)

Refractive Errors

• Presbyopia– Inability of lens to change curvature in order

to focus

• Strabismus– Inability of eyes to focus in same direction

• Corrected with glasses or contacts

Normal Vision

Hyperopia Far Sighted

Myopia-Near Sighted

Foreign Bodies

• May cause excessive tearing and redness

• If particle not located and removed, instill sterile fluorescein drops or strips to visualize minute foreign bodies not readily visible with naked eye

Cataracts

• Disorder that causes lens or its capsule to lose transparency and/or become opaque

• As clouding develops, visual impairment occurs

• Treatment:– Surgical removal of lens

Cataracts

CataractsNormal

• Cataract

Glaucoma

• Disorder characterized by abnormally high pressure of fluid inside eyeball

• Treatment:– Drug therapy to reduce intraocular pressure

and iridectomy• Procedure to facilitate drainage of aqueous humor

Normal

Mild Glaucoma

Severe Glaucoma

Conjunctivitis (Pink Eye)• Inflammation of conjunctiva• Contagious• Causes:

– Bacterial, viral, or rickettsial organisms, allergens, and irritants

• Symptoms:– Burning, itching, discharge, swelling, pain, and

redness of eyes

• Treatment:– Warm compresses and antibiotic ointment

Conjunctivitis

Retinal Detachment

• Painless separation of retina from choroid

• May result from trauma or intraocular disorders

• Treatment:– Procedures that create inflammatory reaction

that results in retina reattaching to choroid and surgery

Retinal Detachment

Macular Degeneration

• Atrophy or deterioration of macula

• Central vision lost, but peripheral vision remains

• May be caused by aging, injury, infection, or inflammation of macula

• Help client maximize ability and prevent further damage if exudative

Macular Degeneration

Severe Macular Degeneration

Keratitis

• Inflammation of cornea

• Causes:– Infection, irritation, injury, and allergies

• Symptoms:– Severe eye pain, red and watering eye,

photophobia, reduced vision, and sometimes rash

• Treatment:– Optical anesthetics, mydriatics, and antibiotic

solutions

(continued)

Stye (Hordeolum)

• Pustular inflammation of eyelash follicle or sebaceous gland on lid margin

• Cause:– Staphylococcal organisms

• Symptoms:– Pain, redness, and swelling

• Treatment:– Warm compresses and topical antibiotics

(continued)

Chalazion

• Cyst of meibomian glands

• Symptoms:– Painless localized swelling that develops over

period of weeks

• Treatment:– Surgical excision

Chemical Burns

• Emergency treatment:– Immediate lavage of eye with tap water

• No attempt should be made to neutralize chemical– May cause further injury

• Both eyes should be patched for comfort

Impaired Hearing

• Conductive hearing loss– Inability of sound waves to reach inner ear

• Sensorineural hearing loss– Inner ear or cochlear portion of cranial nerve

VIII abnormal or diseased

• Once cause determined, client and doctor can decide on best therapy

Ear Website

http://www.bris.ac.uk/depts/ENT/images/different%20forks.jpg

Otitis Media

• Inflammation of middle ear

• Symptoms:– Ear pain, fever, redness of auricle and ear

canal, and sometimes enlarged lymph nodes

• Treatment:– Topical heat, analgesics, antihistamines,

decongestants, antibiotics, myringotomy, and tympanoplasty

Otitis Media

• What treatments would be used for this problem

Myringotomy

Otitis Externa

• Also known as swimmer’s ear

• Bacterial infection of external ear canal

• Symptoms:– Red and edematous canal skin, mild

conductive hearing loss, and discharge

Ménière’s Disease

• Also known as endolymphatic hydrops

• State of hearing loss characterized by tinnitus and vertigo

• Symptoms:– Classic triad of vertigo, tinnitus, and unilateral

fluctuating hearing loss

• Treatment:– Drugs, surgery, and dietary changes

(continued)

Otosclerosis

• Most common conductive hearing loss• Secondary to pathologic change of bones

in middle ear• Symptoms:

– Subtle changes in hearing and low-pitched tinnitus

• Treatment:– Do nothing, hearing aids, and surgical

stapedectomy

Acoustic Neuroma

• Slow-growing and usually benign tumor of vestibular portion of inner ear cranial nerve VIII

• Symptoms:– Dizziness, tinnitus, and hearing loss– May involve other cranial nerves with tumor growth

• Treatment:– Short-term pharmacological therapy and surgical

excision of tumor

(continued)

Mastoiditis

• Inflammation of mastoid

• Causes:– Chronic or recurrent bacterial otitis media

• Symptoms:– Earache, fever, headache, and malaise

• Treatment:– Antibiotics and surgical intervention

Taste

• Serves as protector

• Provides delightful sensations

• Can be altered secondary to neurological disorders or trauma

• Works very closely with sense of smell

Smell

• Serves as guardian from danger

• Disorders of olfactory sense often go unnoticed

• Body cannot regenerate olfactory cells

Touch

• Sensations pertaining to skin

• Tactile receptors located throughout integumentary system

• Clients with reduced or loss of tactile sensation risk injury when condition confines them to bed

Chapter 60

Infants with Special Needs:Birth to 12 Months

Otitis Media

• Inflammation of middle ear

• Symptoms:– Irritability, pulling at infected ear, diarrhea, vomiting,

fever, and hearing loss

• Prevention:– Proper positioning when feeding and smoke-free

environment

• Treatment:– Medications and myringotomy for recurrent

infections(continued)