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; Environment; 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

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

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.