Sensory Perception

Sensory Alteration

Occurs when a person attempts to react to every stimulus within the environment or if the variety and quality of stimuli are insufficient.

Sensory Deficit

A deficit in the normal function of sensory reception and perception. Deficits can affect any of the senses. Can be partial or total.

Expressive aphasia

A motor type of aphasia, the inability to name common objects or express simple ideas in words or writing. Ex. patient understands a question but is unable to express an answer.

A stroke affecting left hemisphere of the brain results in symptoms on the right side such as difficulty with speech.

A stroke on the right hemisphere has symptoms on the left side, which includes visual spatial alterations such as loss of half of a visual field or inattention and neglect, especially to the left side. (Remember that movement and sensation for one side of the body is controlled by the opposite side of the brain)

Aphasia

An impairment of language, affecting the production or comprehension of speech and the ability to read or write. Aphasia is always due to injury to the brain-most commonly from a stroke, but brain injuries may also arise from head trauma, from brain tumors, or from infections.

Sensoristasis

Balance between sensory deprivation vs. sensory overload

Reception

Begins with stimulation of a nerve cell/fiber (called a receptor) (usually for one type of stimulus ex. light, touch, taste, sound. For special senses, the receptors are grouped together like taste buds, or the retina). Nerve impulses are created then travel to the brain.

Stroke

CVA caused by clot, hemorrhage, or emboli disrupting blood flow to the brain. Creates altered proprioception with marked incoordination and imbalance. Loss of sensation and motor function in extremities controlled by the affected area of the brain also occurs.

Manifestations of Sensory Deprivation

Can be -cognitive (decreased ability to concentrate, learn, confusion, disorientation), -affective (restlessness, anxiousness depression, panic, boredom) or -perceptual (decreased coordination, response time, decreased color perception, sense of touch, change in spatial perception and altered judgement)

Proprioceptive Changes

Common after age 60 include increased difficulty with balance, spatial orientation, and coordination. The person cannot avoid obstacles as quickly and the automated response to protect and brace oneself when falling is slower. Also tactile changes, including declined sensitivity to pain, pressure, and temperature secondary to peripheral vascular disease and neuropathies (weakness, numbness, and pain from nerve damage, usually in the hands and feet).

Common Hearing Sensory Deficits

Conductive hearing loss: obstruction, wax accumulation, tympanic membrane perforation, ear infections, otosclerosis. Sensorineural hearing loss: exposure to loud noises, ototoxic meds, aging (presbycusis), acoustic neuroma.

Sensory input affects

Consciousness, arousal, awareness, memory, affect, judgement, awareness of reality, and language.

Factors affecting sensory perception

Developmental stage (babies senses) Culture/Lifestyle/Personality (makes us used to certain smells/sounds, etc.) Stress Level- determines tolerance to stimuli Environment- (ex. work involving physical labor increases risk of damage to touch, vision, hearing, etc)

Common Balance Sensory Deficits

Dizziness and disequilibrium

Reaction is dependent upon

Intensity, contrast, adaptation, and previous experience.

Manifestations of Sensory Overload

Overload prevents the brain from responding appropriately to or ignoring certain stimuli; the patients thoughts race, attention scatters in many directions, and anxiety and restlessness occur.

Hyperesthesia

Overly sensitive to tactile stimuli.

Common Neurological Sensory Deficits

Peripheral neuropathy, stroke.

Common Visual Sensory Deficits

Presbyopia, cataract, dry eyes, glaucoma, diabetic retinopathy, macular degeneration, infection, inflammation, injury, brain tumor.

3 components of any sensory experience

Reception, perception, reaction

Sensory Deprivation

Results from inadequate quality or quantity of sensory stimuli. Can result from illness, trauma, or isolation.

Stereognosis

Sense that allows a person to recognize the size, shape, and texture of an object.

Kinesthetic

Sense that enables a person to be aware of the position and movement of body parts without seeing them.

Perception

Takes place when a person becomes conscious of a stimulus and receives the information. Includes integration and interpretation of the stimuli based on the persons experiences. Perception or awareness of unique sensations depends on the receiving region of the cerebral cortex, where specialized neurons interpret the quality and nature of sensory stimuli.

Sensory perception

The ability to receive and interpret sensory impressions through sight(visual), hearing (auditory), touch(tactile), smell (olfactory), and taste (gustatory), and movement or positioning (kinesthetic).

Reaction

The brain prevents sensory bombardment by discarding or storing sensory information. A person usually reacts to stimuli that are most meaningful or signifiant at the time. The balance between sensory stimuli entering the brain and those actually reaching a person's conscious awareness maintains a person's well-being.

Sensory or Receptive Aphasia

The inability to understand written or spoken language. Ex. a patient is able to express words but is unable to understand questions or comments of others.

Holland's definition of sensory perception

The process of recognition and interpretation of environmental stimuli.

Aphasia

Varying degrees of inability to speak, interpret, or understand language.

Sensory Overload

When a person receives multiple sensory stimuli and cannot perceptually disregard or selectively ignore some stimuli. Excessive, sustained, and unmanageable multi-sensory stimulation.

Common Taste Sensory Deficits

Xerostomia (decrease in salivary production that leads to thicker mucous and dry mouth)