Sensory Perception

sensory perception

the ability to receive sensory input and, through various physiological processes in the body, translate the stimulus or data into meaningful information

eye

•Vision is processed in the occipital lobe

•Crossing at the optic chiasma, joining the left and right eye information in the optic tract, passing through the thalamus (linking to the cortex) and layering the right and left visual stimuli to the occipital lobe

visual pathway

retina -> optic nerve -> optic chiasm -> optic tracts -> lateral geniculate nucleus (LGN) of thalamus -> visual radiations -> visual cortex

eye color

•pigmentation in the iris, not till 6-12 months; Caucasian babies have blue eyes at birth.

eye of baby

•occupies a larger space within the orbit than does an adult's eye; thus more vulnerable to trauma.

When is 20/20 vision reached?

6-7yrs

vision screening

•Px assessment should include corneal light reflex and red reflex.

•Use of an age-appropriate visual acuity screen by around 3 years of life

•referral to licensed optometrist or opthalmologist for problems (or suspected).

what does black in centre of pupil mean

cataracts or hemorrhage

presbyopia

•: loss of near focusing ability

•sometime after 40 yrs

•hardening of lens

•Laser surgery or glasses

vitreous detachment

floaters

gel liquefies causing spots

reduced pupil size

•Muscles lose some strength

•Need more light to read

•Harder to adjust to sudden changes in light (night driving)

dry eyes

•Fewer tears (esp. after menopause)

loss of peripheral vision

•Lose 1 - 2 deg per decade

visual impairment

•Acuity b/w 20/60 and 20/200 in the better eye.

legal blindness

•Acuity less than 20/200 in the better eye or peripheral vision < 20 degrees.

macular degeneration

loss of central vision

black areas mean bleeding

•Most common cause of irreversible vision loss in the western world in individuals over the age of 50 years

•Two Types

•Dry (atrophic), most common 85-90%

•Wet (exudative or neovascular) 10-15%

•Clear Risks: Age, Family History, Smoking, Hypertension and Caucasian; possibly female, light exposure and poor diet

causes of cataracts

-Corticosteroids

-Don't use steroid eye drops

-Uveitis

-Diabetes

-downs

-dystrophia

-familial

-intruterine infections

-elderly

-hypoglycemia

treatment of cataracts

glasses

better lightinh

surgery

phacoemulsification

emulsify the lens, take the proteins and gel them together

ECCE

extra orbital removal of the lens

pt has severe eye pain

call the physician, could be increase in IOP

dry macular degeneration

•Most common, slowly progressive; atrophy of photoreceptors, retinal pigment epithelium and choriocapillaris

•Gradual decrease in vision

•Often asymmetrical

•Signs

•Drusen

•Hyperpigmentation or atrophy

•Enlargement of these areas with visualization of the choroidal vessels

wet macular degeneration

•Less Common but Devastating

•Caused by choroidal neovascularization from the choriocapillaris, which break through defects in the membrane

•May form a membrane under the retina

•Eventually leads to scarring

•Presentation

•Metamorphopsia

•Decreased vision (often sudden); poor prognosis

•Signs

•Retinal thickening, Hemorrhage, exudate, often a yellow/green color

macular degeneration treatment

•Argon Laser: to reduce chance of severe vision loss; usually extrafoveal

•Photodynamic therapy

•Verteporfin: light activated compound that targets the neovascularization but does not damage the retina

•Surgery

•Submacular surgery; macular transplantation

•VEGF (vascular endothelial growth factor) Inhibitors

•Main regulator that promotes angiogenesis; excessive amounts are found; promotes increased vessel permeability, endothelial cell proliferation and inflammation)

•VEGF inhibitors target VEGF receptors (Macugen, Lucentis, Avastin)

glaucoma

•Inhibition of the normal flow and drainage of aqueous humour characterized by optic neuropathy and a specific pattern of visual field defect; damage to optic nerve is irreversible

•Results in increased intraocular pressure (IOP); normal is 10-21 mmHg

Pressure against the retina destroys neurons, leading to impaired vision and eventual blindness.

treatment for glaucoma

eye drops

surgery

primary open angle glaucoma

•bilateral with asymmetry in onset

•Slow progressive rise in IOP (above 21 mm Hg)

•Glaucomatous optic nerve damage

•Visual field loss

•Risk Factors

•IOP, Myopia, Age, Ethnicity, Diabetes and systemic hypertension, migraine and peripheral vasospasm, alcohol consumption, cigarette smoking

Elevated IOP results from increased resistance within the aqueous drainage system and there is retinal ganglion cell death;

symptoms of primary open angle glaucoma

•Commonly asymptomatic

•Detected incidentally

•Mild headache, ocular pain

•Minimal blurring of vision

•Frequent changes in presbyopic spectacles

•Subjective visual field defect

treatment of primary open angle glaucoma

•Avoid conditions that will increase the IOP such as emotional stress, heavy exertion, wearing tight clothing around the neck

•Beta blockers: first line therapy as it lowers IOP by reducing aqueous secretion by effect on the beta receptor in the ciliary process

•Contraindications: bronchial asthma, COPD, heart block, CHF and depression

acute closed glaucoma

•Optic neuropathy which occurs as a result of high intraocular pressure due to closed or narrow angles.

•Risk Factors

•Over 40 years, female, Asian or Chinese ethnicity, family history, anterior shifting of the iris narrows entrance to chamber angle, precipitated by dim illumination, emotional stress, trauma or illness, intense concentration, pharmacological pupil dilatation

•Symptoms

•Present at the ER, sudden onset of acute pain in eye/head, diminution of vision, color halos, lacrimation and anxiety and fatigue, N&V

EMERGENCY

treatment acute closed glaucoma

bring down IOP

give IOP lowering drugs

reduce inflammation

laser therapy

diabetic retinopathy

•A chronic progressive sight threatening disease of the retinal vasculature associated with prolonged hyperglycemia and other conditions linked to diabetes mellitus such as hypertension

myopia

•(nearsightedness); light enters the cornea falls short of the retina. See near objects fine, but difficult seeing far objects, such as a white/chalk board.

hyperopia

•(farsightedness); light enters the cornea but falls beyond the retina. Near objects are blurred (reading a book), distance vision is fine.

astigmatism

•Cornea is shaped more like a football—the oblong shape causes light to focus on two points in the back of the eye, not one.

strabismus

•One eye cannot focus with the other eye because of an imbalance of the eye muscles.

•Most common types involve EXOTROPIA or turning outward and ESOTROPIA or turning inward.

•Diplopia (double vision) may result, and may progress to AMBLYOPIA ("lazy eye") wherein the brain will 'turn down and turn off' images from the weaker eye if untreated.

•Not the same as 'pseudostrabismus' where the eyes may appear slightly crossed but the corneal light reflex is symmetrical

treatment strabismus

patching

prescription glasses

eye muscle surgery

amblyopia

•A neural defect where there is insufficient or inadequate stimulation of the fovea, neural pathway, and/or visual cortex.

•Develops in first decade of life and more severe the earlier it occurs.

•Can result from untreated strabismus, eye trauma, unilateral cataract, or severe eyelid ptosis.

•Tends to run in families. More common in children born prematurely or those affected by developmental delays.

damage to cochlea or nerve conduction

no transmission to thalamus=deaf

hearing pathway

Cochlea

Vestibulococlear nerve

cochlear nuclei

inferior colliculus

thalamus

auditory cortex

conductive hearing loss

•Impaired sound conduction from outer to inner ear

Sound is not conducted efficiently through the outer ear canal to the eardrum and the tiny bones (ossicles) of the inner ear

sensorinerual hearing loss

most common

•Damage to the inner ear (cochlea) or to the nerve pathways from the inner ear to the brain.

•Dysfunction of the perception or interpretation of sound waves

high consonant sounds go first***

treatment of hearing loss

hearing aids

communication devices

speech/language therapy

cochlear implants

ASL

ottits media

ear infection

•inflammation of the middle ear with the presence of fluid.

connected to eustachian tube which is connected to nasopharynx, if you have a bad respiratory infection, you get the debris that builds up

acute otitis media

•to an acute infectious process of the middle ear that may produce a rapid onset of ear pain and fever.

otitis media with effusion

•the collection of fluid in the middle ear space without signs of pain and fever.

water accumulates in the ear but no inflammatory process

looks grey

chronic otitis media with effusion

•lasts 3 months or more.

chronic ear infections in childhood

•can thus delay acquisition of language at this critical juncture of development in early childhood.

criteria for antibiotics for ear infection

•Milder disease, usually due to viruses or less virulent bacteria, resolves equally quickly with or without antibiotics.

•A bulging tympanic membrane, esp if yellow or hemorrhagic, likely bacterial -major diagnostic criterion for AOM.

•Perforation of the tympanic membrane with purulent discharge also = bacterial cause.

•Immediate antibiotic treatment is recommended for children who are highly febrile (≥39°C), moderately to severely systemically ill or who have very severe otalgia, or significantly ill for 48 h.

•For all other cases, parents can be provided with a Rx antibiotics to fill if the child does not improve in 48 h or the child can be reassessed if this occurs

•Amoxicillin 1st line; Amoxicillin-clavulanate if not resolved with amoxicillin tx.

olfaction

•Function of cranial nerve I and part of V

•Strong relationship between taste and smell

taste

•Cranial nerve VII and part of IX

•Nerves in the tongue, soft palate, uvula, pharynx, and upper esophagus

touch impairment

•Impairments range from minor distortion of touch to a complete loss of touch sensation.

•Injury (i.e., decreased ability to sense pain, heat, or cold) may develop.

•Activities of daily living and occupational skills are reduced.