Sensation, Perception, Response (foundations)

stimulis

Sight, sound, taste, touch, pain, or anything that stimulates nerve receptors

reception

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• Receiving stimuli from nerve endings of the skin. Internally, the body transmits impulses along sensory neurons to the CNS

  • ►Adaptation: Some receptors remain activated for the length of the stimuli and others decline in time (i.e. over time you may become unaware of an unpleasant odor or persistent hum of a motor)

Specialized receptors: usually only respond

to 1 type of stimuli

Mechanoreceptors

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• hair follicles detect touch, pressure, vibration

Hair cells:

in the ear for hearing

Thermoreceptors

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• variations in temperature on the skin

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• Proprioceptors

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•  sense of position / balance (muscles, joints, tendons)

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• Photoreceptors

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•  located in the retina to detect visible light

Chemoreceptors

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• taste buds

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• Olfactory Receptors

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• nasal cavity to detect smells

• The sensory experience involves 4 components:

stimulis

reception

perception

arousal mechasnism

Perception

• interpretation of impulses sent to different locations in the brain

  • It is not possible to process all stimuli at once

  • Perception is affected by past experiences, knowledge, & attitude factors (location, number, frequency, and changes)

• Arousal Mechanism (Reticular activating system /RAS)

•  located in the brain stem controls consciousness & alertness. These connections keep us awake, attentive, & observant

  • The level of stimuli needed to remain aroused will vary by person

  • The brain adapts to constant stimuli (music, ticking clock, and ever-changing view)

Responding to Sensations 

intensity

contrast

adaptation

previous experience

• Intensity

factor to responding to sensation

• will excite more receptors (bright light)

• Contrast

factor to responding to sensation

• transition from a very cold environment to warmer location

• Adaptation

factor responding to sensation

• Becoming accustomed to noise, lights, activity, & alarms resulting in “tuning them out” (can be a safety issue as a nurse on a busy unit)

• Previous experience

• factor responding to sensations

• memory of an event may provoke a negative / positive reaction (squirming when an injection needs to be given)

Factors Affecting Function:Developmental Variations:

• Adults & Older Adults 

  • By early adulthood senses, are at their peak unless affected by illness or injury

  • The aging process will affect senses such as:

• Vision: 

• Vision: 

fatcors affecting function

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• he vitreous humor becomes thinner, & “floaters” appear in the visual field. The lens becomes discolored & opaque; pupils become smaller Therefore, less light reaches the retina, limiting vision

• The lens becomes less flexible & less able to focus on near objects

• The ciliary body contracts & lens thickens, bringing loss of visual acuity, decreased ability to accommodate to distance & sudden changes in illumination, with decreased night vision

• Peripheral vision & tear production decreases

factors affecting function

hearing

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• Cerumen is drier & more solid, creating hearing loss

• Scarring occurs (e.g., from previous inflammation over life span)

• Hearing changes commonly include presbycusis (loss of high-frequency tones) & decreased speech discrimination

Factors Affecting Function

• Taste

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• Taste buds atrophy & decrease in number, with less ability to perceive tastes, especially sweetness

• Dry mouth may alter sense of taste

Factors Affecting Function

• Smell

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• Atrophy & loss of olfactory neurons decrease ability to perceive smell (may also alter sense of taste)

Factors Affecting Function

• Touch

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• Loss of sensory nerve fiber & changes in cerebral cortex decrease  ability to perceive light touch, pain, & temperature variations

Factors Affecting Function

• Kinesthesia

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• Kinesthetic changes include a decrease in muscle fiber & diminished conduction speed of nerve fiber, resulting in slowed reaction time, decreased speed & power of muscle contractions, and impaired balance. These place older adults at increased risk for falling

Factors Affecting Function

• Culture

• Affects the nature, type and amount of interaction and stimulation a person may feel comfortable with

  • Eye contact, personal space & physical touch may vary by culture

  • Examples: prayer time, rest time, surrounded by family

  • Key point: Use touch cautiously – for some it may be comforting but for others it may be intrusive or offensive

Factors Affecting Function

• Illness 

neurlogical disorders

circularory diseases

lack of o2 (anoxia)

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• Neurological disorders

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• can slow transmission of impulses affecting sensation & perception (i.e. Multiple Sclerosis)

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• Circulatory diseases

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• altering perception & response (impairment of sensory receptors)

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• Lack of O2 (anoxia)

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• destroys cells and damages neurological system

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• Retinopathy (vision loss)

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•  from diabetes, HTN, sickle cell, and toxoplasmosis (parasitic infection from cats or undercooked meat)

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• Physiologic injury to brain by trauma:

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• Closed head injury (concussion causing bleeding, increased pressure in the brain or a penetrating injury)

Factors Affecting Function

• Medications

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• ASA & Furosemide (Lasix) are ototoxic taken for long periods of time

• CNS depressants, opioid analgesics, sedatives reduce reception and perception 

• Medications that can affect taste and smell examples: antibiotics, antihistamines, steroids, antihypertensive, diuretics, chemotherapy, etc.

Factors Affecting Function

• Stress

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• Undue stress can create tremendous physical & psychological stress (illness, surgery) leading to sensory overload. Try to limit unnecessary stimuli

Factors Affecting Function

• Personality & Lifestyle:

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• Patients are at risk if their stimuli is altered from their current lifestyle

Sensory Alterations: Sensory Deprivation

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• Altered sensory reception where a person does not receive meaningful sensory input 

  • ►Affects hospitalized patients, elderly, ill or injured

Sensory Alterations: Sensory Overload

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• Stimuli such as pain, unfamiliar sights, sounds, odors, and routines overwhelm a person

  • ►Example: ICU’s, ER’s

Sensory Deficits : Visual

myopia

• (nearsighted): cannot see distant objects well

Sensory Deficits : Visual

• Hyperopia

• (farsightedness): near vision is impaired

Sensory Deficits : Visual

• Presbyopia

• Age related vision changes (lens becomes less elastic & less able to accommodate near objects)

Sensory Deficits : Visual

• Astigmatism

• irregular curvature of cornea/lens distorting light rays on the retina distorting the image)

Sensory Deficits : Visual

• Cataracts

•  Clouding of the lens resulting in blurred vision

Sensory Deficits : Visual

• Glaucoma

•  increased pressure in the anterior chamber of the eye distorting shape of the cornea & shifting position of the lens. Loss of peripheral vision or blindness (most common is open angle glaucoma)

Sensory Deficits: Visual

• Macular Degeneration

• loss of central vision due to damage to the macula (central portion of the retina) Risk factors include excessive sunlight & smoking

Sensory Deficits: Visual

• Strabismus

• One eye deviates from a fixed image and can lead to permanent vision loss

Sensory Deficits: Visual

• Retinopathy

• damage to the retina causing vision impairment (detached retina creating an ophthalmic emergency)

Sensory Deficits: Hearing

• Conduction Deafness

• may be temporary or permanent due to an infection of the middle ear, puncture of tympanic membrane, arthritis of auditory bones, cerumen impaction, or foreign object

Sensory Deficits: Hearing

• Sensorineural hearing loss

• nerve deafness occurring from damage to the CN VII or receptors in the cochlea. May result from ototoxic medications, trauma, hereditary causes, bacteria, viral infections, chronic exposure to loud noise 

  • NOTE: hearing aids may not help sensorineural hearing loss

Sensory Deficits: Hearing

• Presbycusis

• sensorineural hearing loss due to aging (especially high-pitched sounds) or inability to distinguish sounds in noisy environments 

Sensory Deficits: Hearing

• Central deafness:

• Damage to the auditory areas of the temporal lobe from trauma, tumor, meningitis or stroke

Sensory Deficits: Hearing

• Tinnitus

•  ringing in ears from damage to the endings of the nerve in the inner ear caused by trauma, Meniere’s disease, HTN, ear infection, medications & otosclerosis of ear bones

Sensory Deficits: Hearing

• Impacted cerumen:

• ear wax becomes impacted in ear canal

Sensory Deficits: Hearing

• Otitis Media

• middle ear infection caused by a virus or bacteria

Sensory Deficits: Hearing

• Otosclerosis

• hardening of bones of middle ear (especially stapes)

Sensory Deficits: Olfactory & Taste

• Olfactory

nerve

• (Olfactory nerve is CN I) Sense of smell

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• Hyposmia

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• reduced ability to smell or detect odor

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• Anosmia

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• inability to smell

• Gustation

• Sense of taste. Taste buds generate nerve impulses that travel along facial & glossopharyngeal nerve (CN VII and CN IX) to the tongue

  • Tip of tongue – sweet and salty

  • Sides of tongue – sour

  • Back of tongue – bitter

  • Soft palate – savory

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• Phantom Taste Disorders

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• unpleasant taste even though nothing is there

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• Hypogeusia

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• reduced ability to taste flavor

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• Ageusia

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•  inability to detect any flavor (common effect of Covid)

• Tactile deficits:

• change or alteration to feel and/or interpret touch, pressure, temperature

  • Triggers: Stroke, brain or spinal tumor, brain injury, peripheral nerve damage caused by diabetes, Guillain barre syndrome, chronic alcoholism, PVD

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• Tactile defensiveness

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• hypersensitivity to touch

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• Tactile Hyposensitivity

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• diminished sensation to touch

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• Tactile apraxia

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• hand movement disturbances when handing objects

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• Phantom sensation

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• Hypersensitive nerve conduction (agitated nerve endings) conducts sensation for a limb not there (post amputee)

Kinesthetic Deficit

• Muscle senses position, movement, & body space

  • Proprioception: Movement stimulates sensory organs, muscles, and bones, to sense position of head & body transmitting signals to the brain

  • Vestibular function: ability to maintain equilibrium & balance with movement

 Kinesthetic Deficit triggers

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• Mismatch between acceleration of head & visual field

• Neurological disorders: Parkinson’s disease, tumor, medication, stroke, problem with inner ear function

• Types of Kinesthetic Disorders:

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• Hyperkinetic: Often with repetitive, involuntary motor activity (tremors, cramps, spasms) 

• Hypokinetic: small movements (Parkinsonian movement)

• Bradykinetic: Slow movements

• Akinetic: Lack of movement

Nursing Process: Assessment

• onduct an overall sensory – perception assessment:

  • Nursing Interview: While taking a history intake, assess current state of overall sensory function (how does the patient answer questions)

  • Physical Assessment: Conduct a focused assessment of the 6 senses: vision, hearing, taste, touch, balance, smell, touch and ability to respond to stimulation, muscle tone, & coordination

  • Assess usual sensory function: In addition to current function, assess for any sensory aids (glasses, hearing aid, dentures, canes, walkers)

  • Assess for risk of impaired sensory perception: older patients, bed-bound / homebound, ICU patients, those with acute / chronic brain injury, limited mobility, or known sensory deficits, developmental level, health status, personality, history of head trauma, & lifestyle alterations related to sensory issues

Nursing Process: Assessment continued

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• Assess mental status: behavior, appearance, response to stimuli, speech, memory, judgment and level of orientation (date, time, location)

• Assess Level of consciousness (LOC): Arousal (alert, lethargic, comatose) and orientation (time, place, person, and situation)

• Assess support network: Who supports patient, assist with ADL’s, or adapt to any deficits

• Assess environment: Evaluate patient’s response to this new environment. If the patient comes from a quiet environment and is exposed to the noises and other environmental issues, it can cause overload / disorientation 

• Assess effect of sensory deficits in this environment: Hearing, vision & balance deficits will require special safety considerations

Nursing Process: Diagnosis

• Confusion?

• Memory Impairment?

• Home Maintenance Alteration?

• Peripheral Alteration?

• Unilateral Neglect?

• Disturbances & deficits in sensory perception may be the etiology of other nursing diagnoses. Examples:

  • Fall Risk r/t impaired vision

  • Injury Risk r/t reduced tactile sensation

  • Bathing/Hygiene Deficit r/t kinesthetic deficit

  • Body Nutrition Deficit r/t loss of appetite secondary to impaired taste

  • Social interaction alteration r/t embarrassment about memory impairment

Nursing Process: Implementation

• Sensory Deficits: Sensory deficit: Vision, hearing, appetite 

• Acute Confusion: Cognitive Stimulation, Reality Orientation, avoid overstimulation

• Chronic Confusion: Anxiety Reduction, Dementia Management

• Impaired Memory:I Memory Training, Neurologic Monitoring, Surveillance

• Unilateral Neglect: Self-Care Assistance, Unilateral Neglect Management

• Specific nursing activities addressing sensory perception problems are based on nursing diagnosis chosen, especially on etiology & patient needs:

  • Incorporate safety measures

  • Use of sensory aids

Nursing Process: Goals / Evaluation

• Compensates for visual impairment by maximizing the use of touch and hearing

• Effectively copes with excessive environmental stimuli

• Demonstrates proper use of hearing aid

• Participates in at least one activity daily

Protect Brain Health

• Promote activity

• Intellectual activities (reading, puzzles, conversation)

• Healthy diet

• Reduce risk factors cardiovascular disease, diabetes, tobacco use

• Avoid mind-altering medication (coordinate with a pharmacist)

• Adequate sleep

• Avoid heavy alcohol consumption

Caring for a Patient with Confusion 

• Promote orientation

  • Introduce yourself & wear readable name tag

  • Identify day, date, time

  • Provide visual cues

  • Place personal objects & mementos in environment

  • Encourage participation in bathing & activities

• Simplify communication

  • Speak slowly

  • Face the patient

  • Provide simple explanations

  • Use short sentences

  • Do not offer too many choices

• Relieve Anxiety

  • Gently hold or pat the patient’s hand

  • Reassure calmly

  • Orient to reality

  • Help them word find

  • Consider alternative therapy - music

Caring for Altered Level of Consciousness

• Conscious: Being wakeful & aware of self, time, and surroundings

• Unconsciousness: Abnormal neurological state. The patient is highly dependent on the nurse for airway management, nutrition, skin care, hydration, & sensory stimulation

• Interventions could include:

  • Eye care: clear lid margins

  • Oral care: NPO

  • Pressure injury prevention: Frequent turning, positioning, and skin care

  • Immobility: ROM exercises to prevent contractures