05-04b: Sensation Flashcards
Role of Sensation - What does it do?
- Guides selection of motor response for effective environmental interactions
- Sensory input –> Motor output
Dermatome
Skin segment innervated by one dorsal root
Attention
Selective awareness of environment or responsiveness to a stimulus or task without being distracted by other stimuli
Orientation
Awareness of person, place, time
Cognition
- The “process of knowing”
- Includes both awareness and judgment
Memory - Examining
- Short-Term: Difficulty following directions, Short list of words, recall list of 7 digits
- Long-Term: Recall date of wedding, where one went to school
Sensory Receptors (3)
- Superficial sensation, Deep sensation, Combined cortical sensation
- Tactile sensation
Superficial sensation (4)
- Pain, Temperature, Pressure, Light Touch
- Exteroceptors receive sensory stimuli from external environment from skin and subcutaneous tissue
- Dermatomes and peripheral nerve distribution
Deep sensation (3)
- Vibration, Proprioception, Kinesthesia
- Proprioceptors provide sensory input
- Stimuli from muscles, joints, tendons, ligaments, fascia
Proprioception
- Position sense and awareness of joints at rest; after movement
- Pt identifies static position of an extremity, trunk or body part - tests deep sensation at that joint, not whole body
Kinesthesia
- Awareness of movement; tests during movement
- Pt identifies dynamic moving part of proprioception; identify direction and extent of movement of a joint or body part; small ROM
Combined cortical sensation
- Stereognosis, Graphesthesia, 2-point discrimination, Barognosis
- Requires both exteroceptors and proprioceptors as well as cortical sensory association areas
- Combination of superficial and deep sensation to form 1 sensation
- Requires interpretation from cortex; processed in parietal lobe
Stereognosis
Identify object by touch without looking at it
Graphesthesia
Ability to recognize numbers, letters, shapes “written” on the skin with finger trace
2-point discrimination
- Ability to perceive two points applied to the skin simultaneously
- Test with 2-point caliper
Barognosis
Ability to recognize the difference in the weight (lighter or heavier) of objects by feeling, not looking
Sensory impairment patterns
- Dermatome distribution: Nerve roots
- Peripheral nerve distribution: Includes entrapments
- “Glove and Stocking”: Starts with whole foot/feet and spreads to whole hand(s); Associated with peripheral neuropathy, DM
- MS: More scattered distribution because of CNS pathology
- SCI: Nerve root distribution below level of injury
Sensation testing
- Superficial: Pain, Pressure, Light Touch, Temperature
- Deep: Vibration, Proprioception, Kinesthesia
- Cortical: Stereognosis, Barognosis, Graphesthesia, 2-point discrimination
- Also includes taste, smell, hearing, vision
Sensory data results
Categories: Absent, impaired, delayed, intact
Snellen Chart
- Tests vision
- Mounted on wall 20 feet away (the first “20”), then based in line they can correctly read comfortably
Peripheral field test
Finger moves toward center until it reaches field of vision
Light Touch Test
- Use light touch or stroke; do not indent skin
- Cotton ball or light pressure with finger
Pressure test
- Press enough to indent skin for pressure receptors
- Dull side of safety pin or finger
Pain test
- Sharp/dull discrimination
- Pin prick
