Concept of Sensory
Alteration
Normal Sensory Perception
• Sensory perception depends on the sensory receptors,
reticular activating system (RAS), and functioning
nervous pathways to the brain. The RAS influences
awareness of stimuli, which are received through the five
senses: sight, hearing, touch, smell, and taste.
Kinaesthetic
• and visceral senses are stimulated internally.
• Reticular activating system (RAS)
• It is responsible for bringing together information from
the cerebellum and other parts of the brain with the
sense organs.
• The RAS is highly selective. For example, a parent may
be awakened in the middle of the night at the slightest
murmur of an infant in a bedroom down the hall but may
sleep through the loud traffic noises outside the bedroom
window. Destruction of the RAS produces coma and an
electroencephalograph pattern characteristic of sleep.
Input of Senses
Sensory function begins with reception of stimuli by the senses.
Externally, the senses receiving stimuli are;
• Vision, hearing, smell, taste, and touch.
Receptor organs are
• The eyes, ears, olfactory receptors in the nose, taste buds of the
tongue, and nerve endings in the skin.
• Internally, the kinaesthetic and visceral senses receive stimuli.
These receptors are nerve endings in the skin and body tissues.
The kinaesthetic sense influences awareness of the placement
and action of body parts. The visceral sense receives stimuli that
affect awareness related to the body's large interior organs.
Vision, hearing, smell, and taste are termed, special senses.
Touch, kinesthetic sensation, and visceral sensation are termed
somatic senses. After stimuli are received, they are perceived
with the help of the RAS. Sensory perception is a consociates
process of selecting, organizing, and interpreting sensory stimuli
requiring intact and functioning sense organs, nervous pathways,
and the brain.
Characteristics of Normal Sensory Perception
• These are the normal measures in quality and quantity
of the special and somatic senses.
• Normal vision is associated with visual acuity at or near
20/20, full field of vision, and tricolour vision (red,
green, blue).
• Normal hearing is associated with auditory acuity of
sounds at an intensity of 0 to 25 dB, at frequencies of
125 to 8,000 cycles per second.
• Normal taste involves the ability to discriminate sour,
salty, sweet, and bitter.
• Normal smell involves the discrimination of primary
odours, such as cainphoraceotrs, musky, floral,
peppermint, ethereal, pungent, and ptitrid.
• Somatic senses include discrimination of touch,
pressure, vibration, position, tickling, temperature, and
pain.
Normal Sensory Pattern
• Sensor stasis
Each person has his or her own comfort zone. This comfort zone
varies from person to person and is the range at which a person
performs at his or her peak. Sensor stasis is a state of optimum
arousal-not too much and not too little. The RAS is viewed by
some theorists as a monitor for sensor static balance.
• Adaptation
Beyond the point of sensor stasis, sensory adaptation occurs.
Sensory receptors adapt to repeated stimulation by responding
less and less. Lead time and after burn are two necessary time
periods crucial to helping a person deal with new stimuli.
– Lead time is the time each person needs to prepare for an event
emotionally and physically.
– After burn is the time needed to think about, evaluate, and come
to terms with the activity after it happens.
• The necessary amount of lead time and after burn is different for
each person. Lead time and after burn helps person process
stimuli so he or she can respond appropriately without becoming
overwhelmed.
Factors Affecting Sensory Perception
Environment
• Sensory stimuli in the environment affect sensory
perception. For example, a teacher may not notice
the noise in a consistently noisy environment, such
as the school cafeteria. But the same teacher may
perceive a loud television set very differently in his
or her own home, which is usually quiet.
Previous Experience
• It affects sensory perception in that people become
more alert to stimuli that evoke a strong
• response. For example, a person may drive to work
by the same route each day, noticing little along the
way. A person may listen to the radio inattentively
until a favourite song is played, then listen to every
word. A new experience, such as hospitalization,
may cause a client to perceive a barrage of
threatening new stimuli.
Lifestyle and Habits
• It affects sensory perception. One person may enjoy a
lifestyle surrounded by many people, frequent changes,
bright lights, and noise. Another person may prefer less
contact with crowds, less noise, and a slow-paced
routine. People with different lifestyles perceive stimuli
differently.
• Cigarette smoking causes atrophy of taste buds,
decreasing sensory perception of taste. Chronic alcohol
abuse may lead to peripheral neuropathy, a functional
disorder of the peripheral nervous system those results
in sensory impairment.
Illness
• Certain illnesses affect sensory perception. Diabetes
and hypertension cause changes in blood vessels and
nerves, leading to visual deficits and decreased
sensation of touch in the extremities. Cerebrovascular
disorders impair blood flow to the brain, possibly
blocking sensory perception. Pain, fatigue, and stress
caused by illness also affect perception of stimuli.
Medications
• Some antibiotics, including streptomycin and gentamicin, can
damage the auditory nerve, impairing hearing. Central nervous
system (CNS) depressants, such as narcotic analgesics, decrease
awareness and impair perception of stimuli.
Variations in stimulation
• If a person experiences more sensory stimulation than he or she is
used to or can make sense of, distress and sensory overload may
occur.
• On the other hand, if a person experiences less than the usual
stimulation, that person is below his or her optimum state of
arousal and may be at risk for sensory deprivation.
• Reactions to sensory overload or sensory deprivation are special
challenges that nurses frequently encounter in themselves and
clients. Sensory overload and deprivation can lead to perceptual,
cognitive, and decisional problems. When the RAS is overwhelmed
with input, a person may experience sensory overload and feel
confused, anxious, and unable to taken constructive action . When
the RAS fails to recognize a stimulus because it is below the
threshold level or lacks relevant meaning to the person, sensory
deprivation may occur, and the person experiences depression,
restlessness, and hallucinations
Sensory overload
• It occurs when a person is unable to process or manage
the intensity or quantity of incoming sensory stimuli. The
person feels out of control and overwhelmed by the
excessive input from the environment. Routine activity in
the health setting can contribute to sensory overload in
clients.
• These activities fall into three main categories:
– internal factors,
– information, and
– environment .
• Internal Factors;
• such as thinking about surgery or the meaning of a
medical diagnosis, can contribute to anxiety and
cognitive overload so that the person cannot process
additional stimuli. Pain, medication, lack of sleep, worry,
and brain injury also can contribute to a person's
vulnerability to sensory overload.
• Information;
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It is Imparting information to a client may lead to sensory overload.
Some examples include teaching a client about a procedure,
informing a client about a diagnosis, making requests of a client, or
helping the client solve a problem. Anxiety related to medical
diagnosis, prognosis, and treatment can contribute to sensory
overload. Lights and frequent activity may cause sensory overload in
a premature newborn in the neonatal intensive care unit.
• Environment;
• The environment of the healthcare agency provides a higher than
usual amount of sensory stimulation. A client newly admitted to the
hospital, for example, may have to cope with adjusting to a new
roommate, having the television on more than usual, bright lights,
paging systems, meeting many staff members, having the bed move
up and down at someone else's bidding, waiting for someone to
answer the call light, uncontrolled pain, and having strangers touch
and not respect private body areas. Clients in intensive care units
often exhibit symptoms of sensory overload because of the high
degree of light, noise, and activity around the clock.
Sensory Deprivation
• Although sensory deprivation can be
thought of as the opposite of sensory
overload, they share many elements.
• Sensory deprivation generally means a
lessening or lack of meaningful
sensory stimuli, monotonous sensory
input, or an interference with the
processing of information.
Sensory deprivation (under stimulation)
It can be just as disruptive as sensory overload. Cognitive
and emotional deterioration can occur when stimuli are
reduced below a person's optimum level of stimulation.
One common source of sensory deprivation is a sudden
decrease in stimuli when a person moves from a fast- to a
slow-paced environment.
• Each person's tolerance of and reaction to a lessening or
lack of meaningful sensory stimuli differs, but clients with
extreme cases experience a gross misperception of
events and personality changes. Any time a client
experiences an interference with or a diminution of
sensory input, that person may be at risk for sensory
deprivation.
• In the hospital such occurrences fall into two general
categories:
– altered sensory reception
– deprived environments;
Altered sensory reception
• Occurs in such conditions as spinal cord injury,
• brain damage, changes in receptor organs,
sleep deprivation, and chronic illness. The
person does not receive adequate sensory
input because of an interference with the
nervous system's ability to receive and process
stimuli.
Deprived environments
• It can have negative effects on a person's
sensor stasis. A person who is immobilized or
isolated for any reason is deprived of the usual
amount of stimulation and may show
manifestations of sensory deprivation
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Manifestations of Altered Sensory
Perception Function
Anxiety
Cognitive Dysfunction, which is a
Disturbance in remembering, reasoning, and
problem solving may occur with sensory
overload.
Hallucination and Delusions (beliefs not
based in reality) reflect an unconscious need
or fear
Sensory Deficit
Depression and withdrawal
Impact on Activities of Daily Living
• Sensory perception dysfunction may have effects on activities of
daily living (ADLs). Visual deficits cause problems with self-care
activities as basic as dressing, toileting, and preparing meals.
Hearing deficits may restrict people from watching television,
listening to the radio, and answering the telephone. Safety hazards
also exist for who are hearing impaired.
• People with taste and smell deficits may lose interest in eating.
• Those with sensory deficits involving touch are at risk for burns and
injuries to the extremities. Moving around outside the home may be
impossible without special aids or help .
• Many jobs are prohibited for people with sensory deficits, and driving
may not be allowed.
• This further restricts the environments in which they may move about
safely, making them dependent on others. If the affected person is
the major wage earner, a reduction in or loss of income may occur.
• People with cognitive dysfunction from sensory overload or
deprivation may exhibit poor judgment and problem solving during
everyday activities, increasing the necessity for family members to
monitor activities and decisions.
All these concerns place more stress on the family to cope with sensory
dysfunctions.
Risk Factors for Sensory Perception Dysfunction in the
Healthcare Environment
Sensory Overload
• Room close to nurse's station
• ICU or intermediate unit
• Bright lights
• Use of mechanical ventilator
• Use of ECG monitor
• Use of oxygen
• Use of IVs
• Other equipment
• Frequent treatments
Sensory Deprivation
• Private room
• Eyes bandaged
• Bed rest
• Sensory aid not available (hearing aid, glasses)
• Isolation precautions
• Few visitors
Diagnostic Statement:
• Sensory/Perceptual Alterations
• Definition; Sensory/perceptual alteration is a
• state in which a person experiences a change in the amount or
patterning of oncoming stimuli, accompanied by a diminished,
exaggerated, distorted, or impaired response to such stimuli
(NANDA, 1999) .
Nurse-Client Interaction
• It promotes sensory health function. Clients at risk for sensory
deprivation may need frequent interaction initiated by the nurse. In
any case, provide appropriate: stimuli, such as addressing The Client
by name, explaining all activities, and, when leaving, acknowledging
client that the nurse will return. Length, tendency, and content of
interactions should he based on individual needs. Talking to the
client, showing the client equipment or articles used in care,
encouraging
• the client to smell and taste food that is served, and touching the
client are appropriate stimuli during interactions
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Nursing Interactions for Altered
Sensor- Perception function Stimulation
Providing meaningful external stimuli can help
a client overcome sensor' deprivation or
sensory deficit as; playing the television or the
radio occasionally. playing tennice,
Encouraging use of a clock and calendar,
Encouraging the client to dress or the day's
activities, putting till pictures,
Encouraging visitors, opening the drapes, and
turning on lights.
Plan: the bed or chair so the client can see or
hear activities in the area.