Adult Physical Dysfunction Rehabilitation Lab: Week 2

Sensation, Perception, Vision, Cognition Evaluation
- Relevant Chapters: $9, 22, 23$ , and earlier material.
- Specific Evaluation Tools and Techniques:
  - Semmes-Weinstein Monofilament Evaluation
  - Two-Point Discrimination testing
  - Pain Scales
  - Visual Evaluation
  - Cognition Evaluation (e.g., Mini Mental State Examination)
  - Perceptual Evaluation
Therapeutic Toolkit & Low Vision

Impact of Sensory Dysfunction
- Sensory dysfunction significantly affects clients' performance in daily occupations like Activities of Daily Living (ADLs) and education.
- Sensibility is a client factor, a body function component, influencing both motor and processing aspects of performance skills.
- All clients with sensory dysfunction, regardless of its cause (etiology), require evaluation to determine the occupational impact of their sensory loss.
- Specific sensory tests and interventions are tailored based on the client's diagnosis and prognosis for recovery.
Evaluation Based on Neurological Origin
- The choice of sensory tests depends on whether the diagnosis originates from the Central Nervous System (CNS) or the Peripheral Nervous System (PNS).
- CNS Injury: More likely to result in deficits in:
  - Proprioception: Sense of body position.
  - Kinesthesia: Sense of body movement.
  - Stereognosis: Ability to identify objects by touch.
- PNS Injury: More likely to result in deficits in:
  - Pressure threshold.
  - Two-point discrimination.
- Example: A person with a history of Cerebrovascular Accident (CVA, a CNS injury) who then sustains a wrist fracture (potentially PNS involvement) should be evaluated for both CNS-related deficits (proprioception, stereognosis) and PNS-related deficits (pressure threshold, two-point discrimination).

Exteroceptors
- Adapted for receiving stimuli from the external world (outside the body).
- Examples: Visual, auditory, tactile, olfactory, and gustatory receptors.
Interoceptors
- Receive sensory information from inside the body (viscera - hollow organs and glands).
- Detect internal body sensations such as stomach pain, pinched spinal nerves, or inflammatory processes deep in the skin.
Proprioceptors
- Located in muscles, tendons, and joints, and in the utricles, saccules, and semicircular canals (labyrinths) of the inner ear.
- Detect body position and movement.

Visual Receptors: Rods and cones of the retina; considered exteroceptors.
Olfactory Receptors: Hair cells in the mucous lining of the nasal canal; considered exteroceptors.
Auditory Receptors: Hair cells of the cochlea; considered exteroceptors.
Gustatory Receptors: Taste buds in the tongue; considered exteroceptors.
Equilibrium: Semicircular canals, utricles, and saccules of the inner ear; considered proprioceptors.

Mechanoreceptors: Detect touch, pressure, stretch, vibration, proprioception, equilibrium, and audition. Stimulated by mechanical deformation (e.g., hair cells of the labyrinth system, skin receptors, skeletal muscles).
Chemoreceptors: Respond to cell injury or damage; stimulated by substances released by injured cells. Involved in olfaction and gustation.
Thermoreceptors: Respond to heating or cooling (changes in temperature).
Nociceptors: A subset of all receptor types that sense pain when stimulated. Located throughout the organism's external and internal body.
Photoreceptors: Detect light on the retina of the eye.

Also known as cutaneous sensation.
Receptor Density and Receptive Fields:
- Distal body parts (fingertips, lips, face, soles of feet) have a higher density of receptors and smaller receptive fields, contributing to enhanced fine discrimination (e.g., distinguishing between one and two close stimuli).
- Proximal parts (legs, abdomen, arms, back) have larger receptor fields, used for gross discrimination.
Functional Significance: Normal two-point discrimination allows a person to distinguish the edge of a dime from a penny with vision occluded.
Components: Includes touch (pressure and vibration), pain, and temperature.

Definition: An unpleasant sensory and perceptual experience associated with actual or potential cellular damage.
- It is subjective and multidimensional.
Transmission Pathways:
- Fast Pain: Perceived by free nerve endings, transmitted along small, myelinated A-delta fibers. Characterized as sharp and well-localized.
- Slow Pain: Onset when tissue is damaged, characterized by an aching quality. Travels via smaller, unmyelinated C fibers, resulting in slower conduction velocities. Slow pain is difficult to localize due to its use of various pathways.

Somatic Pain: Originates from the body (e.g., skin, skeletal muscles, bones).
- Superficial Somatic Pain: Usually well-localized (e.g., a pinprick).
- Deep Somatic Pain: Commonly poorly localized (e.g., a muscular ache).
Visceral Pain: Originates from the viscera (internal organs, glands, smooth muscle).
- Dull, diffuse, and not well localized.
- Often accompanied by an autonomic nervous system response (e.g., changes in heart rate, respiration, blood pressure; nausea; dilated pupils; perspiration; pallor).

Dull Ache: Tends to be diffuse.
- Lasts a long time because it is carried by slow-conducting, small, unmyelinated C fibers.
Sharp Pain: Tends to be well-localized.
- Lasts a short time because it is carried by fast-conducting, large A-delta fibers.

Numerical Scale: Ranges from $0$ (no pain) to $10$ (worst pain imaginable).
- $0-10$ integers available for patient selection.
Visual Analog Scale (VAS):
- A line with