Notes for Week 2: Sensation, Perception, and Cognition in Adult Physical Dysfunction Rehabilitation

Sensation, Perception, and Cognition in Adult Physical Dysfunction Rehabilitation

  • Evaluation and observation of deficits in sensation, perception, and cognition

    • Sensation components

    • Somatosensory system includes touch, deep pressure, pain, proprioception, and thermal sensation

    • Tactile: sensation received through skin or hair receptors

    • Deep pressure: force applied to skin (e.g., ischial tuberosities pressing into chair seat)

    • Pain: unpleasant or noxious tactile sensation

    • Thermal sensation: sense of heat or cold

    • Proprioception: information about joint position and motion from muscles, joints, ligaments, and bones at an unconscious level

    • The somatosensory system and task performance

    • Example: brushing teeth

      • Touch lets you feel the toothbrush

      • Deep pressure helps grip the toothbrush

      • Pain signals to avoid brushing sensitive areas

      • Proprioception guides arm/hand joints through brushing motion

      • Thermal senses assess water temperature for rinsing

    • System basics

    • Peripheral receptors in skin and other sense organs control somatosensation

    • Proprioceptive receptors reside in muscles, tendons, and joint capsules

    • All sensory information is processed through the spinal cord and brain

    • Some sensations trigger motor responses before conscious perception (e.g., withdrawal from hot object via reflex)

  • Sensation and motor performance framework

    • Sensation as a primary means of learning about the external world

    • Sensory information roles in movement control: initiation, modulation, and regulation of movement

    • Sensory feedback to the brain during motor acts evaluates effectiveness of motion

    • Ongoing movement sensations are sent to the CNS for comparison of intended vs. actual action

  • Feed-forward vs. feedback control

    • Feed-forward control operates faster than feedback; plans rapid movements before execution

    • Uses sensory information to predict disturbances and develop motor plans

    • Example: skiing: anticipate slope, snow condition, speed, obstacles, path; assume posture, set muscles, initiate motion, balance, move toward destination

    • During execution, continuous feedback corrects errors; feed-forward reevaluates as needed

  • Effects of sensory loss on movement

    • Proprioception and tactile sensation are essential for both feedback and feed-forward control

    • Impaired sensation leads to deficits in both feedback and feed-forward control

    • Proprioceptive dysfunction: inability to sense joint position and motion

    • Tactile dysfunction: inability to sense contact with objects

    • If motor dysfunction is present, coordination may be further impaired

    • Vision may partially compensate for tactile/proprioceptive loss

  • Functional scenarios for evaluation and intervention

    • Dressing, feeding, toileting, transfers, bed mobility, functional mobility

    • Encourage YouTube exploration for potential examples

  • Sensation evaluation, intervention, and therapeutic activities

    • Sensation and sensory dysfunction affect performance in activities of daily living (ADLs) and education

    • Sensibility is a body function and a client-factor in performance skill components

    • All clients with sensory dysfunction should be evaluated to determine occupational impact

    • Specific sensory tests and interventions vary by diagnosis and prognosis

    • Test selection may depend on CNS vs PNS origin

    • CNS injury: deficits often in proprioception, kinesthesia, stereognosis

    • PNS injury: deficits in pressure threshold and two-point discrimination

    • Example: CVA with wrist fracture requires evaluation of proprioception, stereognosis, pressure threshold, two-point discrimination, etc.

  • Sensory receptors and modalities

    • Three types of sensory receptors (Gutman 2008)

    • Exteroceptors: external world stimuli (visual, auditory, tactile, olfactory, gustatory)

    • Interoceptors: internal body sensations (viscera, glands)

    • Proprioceptors: muscles, tendons, joints; inner ear labyrinths

    • Somatosensory system organization

    • Receptors respond to specific stimulus types; travel via spinal cord to brain

    • Receptors categorized as mechanoreceptors, chemoreceptors, thermoreceptors

  • Special sense receptors overview

    • Visual receptors: rods and cones (retina; exteroceptors)

    • Olfactory receptors: hair cells in nasal mucosa (exteroceptors)

    • Auditory receptors: hair cells in cochlea (exteroceptors)

    • Gustatory receptors: taste buds on tongue (exteroceptors)

    • Vestibular: semicircular canals, utricles, saccules (proprioceptors)

  • Somatosensory receptors and subtypes

    • Mechanoreceptors: respond to touch, pressure, stretch, vibration, proprioception, temperature, etc. (skin, muscles, hair cells)

    • Chemoreceptors: respond to cellular injury signals; involved in olfaction and gustation

    • Thermoreceptors: respond to warmth and cooling; include nociceptors for pain

    • Photoreceptors: respond to light (retina)

  • Sensation levels and discrimination

    • Superficial (cutaneous) sensation: touch, pain, temperature; density of receptors higher in distal parts (fingertips, lips, face, soles) for fine discrimination

    • Fine touch: Meissner’s corpuscles (light touch, vibration), Merkel’s discs (pressure)

    • Subcutaneous fine touch: Pacinian corpuscles (touch, vibration), Ruffini’s endings (skin stretch)

    • Hairy skin: transduction similar to glabrous skin; desensitization strategies may consider hair growth direction

    • Coarse touch: free nerve endings mediate itch, tickle, pain, and temperature; C fibers convey slow pain; A-delta fibers convey fast pain (cold)

  • Temperature and pain

    • Testing temperature helps prevent burns when applying heat/cold modalities

    • Thermal receptors contribute to safe bathing, dishwashing, cooking

    • Pain: subjective, multidimensional; free nerve endings signal pain via A-delta (fast, sharp) and C fibers (slow, ache)

    • Pain types: somatic (body structures) vs visceral (organs); somatic pain can be superficial or deep; visceral pain is dull and diffuse with autonomic responses

    • Pain qualities: dull ache (slow C-fibers) vs sharp (fast A-delta fibers)

  • Pain assessment tools

    • Pain scales

    • Numerical scale: 0 to 10; patients indicate current intensity

    • Visual Analog Scale (VAS): line from no pain to worst pain; uses patient’s approximate position

    • Categorical scale: none, mild, moderate, severe

    • Pain faces scale: faces representing pain intensity levels

    • Example scales shown in the source (adapted):

    • Numerical scale: 0-10

    • VAS: lines often interpreted qualitatively; worst vs no pain

    • Faces scale: 0 to 10 with corresponding expressions

  • Dermatome and myotome distributions

    • Dermatome distribution mapping (pages 26) and myotome distribution (page 27) referenced for sensory/mkeletal testing

      Sensation is what our body feels, like touch, deep pressure, pain, temperature, and proprioception (knowing where our body parts are without looking). These sensations are vital for performing simple tasks, like brushing your teeth, where you need to feel the brush, grip it, avoid pain, and guide your hand.

      Our sensory system works by sending information from receptors in our skin and muscles up to the spinal cord and brain. These signals help us learn about the world and are crucial for controlling our movements, both by planning actions ahead of time (feed-forward) and by correcting them as we go (feedback).

      If someone loses sensation, especially proprioception (joint position) or tactile (touch) sensation, it becomes much harder to move and coordinate. Vision can sometimes help make up for this loss.

      Testing Sensation

      OTAs evaluate how sensory problems affect a person's ability to do daily activities (like dressing or feeding).

      Different tests are used depending on whether the problem comes from the brain/spinal cord (CNS) or nerves outside them (PNS):

      • Dermatomes map out specific skin areas that get sensation from a single spinal nerve.

      • Myotomes map out muscle groups that are controlled by a single spinal nerve.

      • Semmes-Weinstein Monofilaments check how well someone can feel light touch and if they have protective sensation (the ability to feel pressure that warns of injury).

      • Two-Point Discrimination (2PD) tests how well someone can tell two close points apart on their skin.

      There are also tools like Sensory Dowels to help retrain touch discrimination, and tests for recognizing objects by touch (stereognosis) or knowing where your limbs are (proprioception).

      Perception and Cognition

      Perception is how our brain makes sense of the sensory information it receives. It's about understanding what we feel, see, or hear.

      Cognition involves thinking and mental processes. Problems can include:

      • Apraxia: Difficulty with planned movements, not due to weakness.

      • Agnosia: Trouble recognizing objects, despite good vision.

      • Aphasia: Problems with speaking or understanding language.

      The A-ONE evaluation framework describes many neurobehavioral issues, like impaired attention, memory loss (short-term or long-term), difficulty organizing tasks, poor judgment, or denial of disability (anosognosia). These cognitive challenges significantly impact a person's ability to perform daily activities safely and independently.

  • Semmes-Weinstein Monofilament testing

    • Purpose: sensory testing to classify touch and protective sensation thresholds

    • Filaments ranges and colors (example site interpretation)

    • 1.65-2.83 (Green)

    • 3.22-3.61 (Blue)

    • 3.84-4.31 (Purple)

    • 4.56 (Red)

    • 6.65 (Red; deeper loss)

    • Interpretations

    • Normal: Green (1.65-2.83)

    • Diminished light touch: Blue (3.22-3.61)

    • Diminished protective sensation: Purple (3.84-4.31)

    • Loss of protective sensation: Red (4.56)

    • Deep pressure sensation: Red (6.65)

    • Testing guidance

    • Test both upper extremities for comparison; bilateral nerve compressions are common

    • Map distribution across radial, median, ulnar nerves; dorsal channels also tested

    • Practical notes from the protocol (page 28-30)

    • Documentation format includes patient name, physician, date, tested sides, and interpretations

    • Some pages show sample data with both right and left hand results

  • Two-point discrimination testing

    • Interpretation guidelines

    • Less than 6 ext{ mm}: Normal

    • 6-10 ext{ mm}: Fair

    • 11-15 ext{ mm}: Poor

    • Perceived protective sensation vs anesthesia scoring also noted

  • Sensory re-education tools

    • SENSORY DOWELS (Rolyan Sensory Re-Education Wands)

    • 10 textured wands graded from 1 (smooth) to 10 (rough)

    • Phases of sensory progression (Phase 1–Phase 10) cover increasing texture and discrimination challenges (pompom, soft plastics, sharp chips, rough plastics, disks, shavings, pebbles, marbles, etc.)

  • Vision and hearing considerations

    • Vision: visual acuity, peripheral vision, visual scanning, tracking, accommodation, field of vision, usage of visual aids

    • Hearing: intact, impaired, or absent; hearing aids

  • Perception: definition and scope

    • Perception is the process of attaining awareness or understanding from sensory information

    • Etymology: perceptio, percipio; means receiving, collecting, apprehension with the mind or senses

  • Apraxia, Agnosia, and Aphasia (A-ONE framework)

    • Apraxia: impairment of voluntary movement not due to muscle deficit or comprehension difficulty

    • Agnosia: impairment in object recognition not due to sensory deficit

    • Aphasia: speech/language disorder; issues with word choice, grammar, comprehension; not due to motor deficits

    • A-ONE terminology (CD vs OD)

    • Conceptual Definitions (CD): definitions of concepts themselves (abstract)

    • Operational Definitions (OD): how concepts are measured or observed (specific tests/items)

  • Selected A-ONE cognitive and perceptual deficits with CD/OD contrasts

    Aggression

    • CD: angry, destructive ideas/behaviors intended to injure

    • OD: shows hostility toward activity or people; may throw objects at therapist

      Anomia

    • CD: loss of ability to name objects or retrieve names (fluent speech)

    • OD: difficulty naming objects; e.g., asks for “the thing for drinking coffee”

      Anosognosia

    • CD: denial of a paretic extremity; lacks insight into paralysis

    • OD: does not identify own paralyzed limb; may misattribute it as another object

      Apathy

    • CD: flat affect, slowed psychomotor activity, lack of environmental interest

    • OD: lack of emotion during activity; indifference; slow performance

      Associative Visual Agnosia

    • CD: difficulty naming objects seen despite adequate perception

    • OD: can use object but cannot name it when only visual cues are provided

    • Apraxia variants (Ideational, Ideomotor, Motor)

    • Ideational/apraxia: breakdown of knowing what to do; sequencing and use of tools

    • Ideomotor/apraxia (Motor): planning and sequencing of movements; e.g., adjusting grip while moving a brush

      Asterognosis (Tactile Agnosia)

    • CD: failure to recognize objects by touch; can't discriminate shape, texture, size, weight

    • OD: needs observation of performance; cannot identify objects by touch alone; may compensate visually

    • Attention impairments; distractibility; field dependence

      Dysarthria; Echolalia

    • Hemianopia (Homonymous Hemianopia)

    • Right-Left Discrimination Impairment

    • Spatial relations impairment; Spatial neglect (unilateral body/visual/spatial neglect)

    • Topographical disorientation

    • Memory deficits: short-term, long-term, working memory loss

    • Somatognosia and Somesthetic sensory loss

    • Locational and perceptual disorders: visual object agnosia, proprioception, stereognosis (astereognosis)概

    • Wernicke’s Aphasia (Sensory/Receptive Aphasia): difficulty understanding language; fluent speech with impaired comprehension

  • Additional cognitive assessment tools and tests

    • Mini Mental State Examination (MMSE): overview of scoring sections

    • Orientation (year, season, date, day, month; location; institution; etc.)

    • Registration of three objects; memory recall; attention and calculation (world backwards or serial subtractions)

    • Recall of objects; language naming; repetition; command following (three-stage command); reading and following written instruction; writing a sentence; copying geometric shapes

    • Cognitive evaluation items include: orientation, recognition, problem solving, categorization, memory recall, attention, sequencing, and executive function components (initiation, planning, insight, judgment, safety)

  • Orientation, memory, and problem solving practice items

    • Orientation questions (name, month, location, holiday, problems present)

    • Recognition: name-based recognition and object identification from pictures

    • Problem solving: hypothetical situations (e.g., wound infection, chest pains, falls at home)

    • Long-term and short-term memory prompts; immediate recall sequences; digit spans (3–7 digits presented forward)

    • Memory tasks include visual memory prompts (household items), auditory memory (paragraph recall), and memory-for-multisensory tasks

  • Functional tasks and cognitive challenges in OT practice

    • Directions and scheduling problems (Mary’s schedule): planning activities with time constraints

    • Categorization tasks: groceries, tools, clothing, personal items

    • Spatial relations and sequencing tasks: toothbrush brushing order; sequencing daily activities

    • History of real-world tasks: problem solving for daily living activities and safety

  • Vision and visual-perceptual skills in OT practice

    • Visual-perceptual skills development follows a sequential pattern (form perception precedes visuomotor integration)

    • Visual perception assessment focuses on discrimination, figure-ground, spatial relations, form constancy, and visual memory

    • Visual perceptual activities include spot-the-difference, I Spy, jigsaws, and memory games; use of commercial visual-perception games as adjuncts

  • Practical evaluation tools and sessions

    • Stereognosis: object recognition by touch; testing with vision occluded; bag-with-objects tasks; cues for non-verbal clients

    • Proprioception and kinesthesia testing procedures

    • Proprioception: test with vision occluded; limb-position judgment (up/down, front/back) at elbow or fingers; static limb positioning

    • Kinesthesia: movement-direction identification; vision occluded; limb moved in a direction and patient identifies whether up, down, forward, or backward

  • Practical implications and integration into therapy

    • Tests and assessments are chosen based on CNS vs PNS origin, lesion location, and prognosis

    • Interpretation informs OT interventions for ADLs, education, and functional mobility

    • The overall aim is to map sensory and perceptual deficits to functional limitations and to tailor compensatory strategies and rehabilitation plans

  • References (for further reading)

    • Early, M. B. (2013). Physical Dysfunction Practice Skills for the Occupational Therapy Assistant (3rd ed.). Mosby

    • Gillen, G. (2009). Cognitive and Perceptual Rehabilitation. Mosby

  • Quick-form reference points to support study

    • Somatosensory modalities: touch, proprioception, nociception, temperature

    • Extero-, intero-, and proprioceptors; receptor types and their pathways

    • Distinctions: superficial vs fine touch; coarse touch; temperature; pain and differential fiber types (A-delta, C)

    • Pain dimensions and scales; pain quality descriptors; somatic vs visceral pain

    • Sensory testing tools: Semmes-Weinstein monofilaments; two-point discrimination; sensory re-education kits

    • A-ONE framework for cognitive/perceptual disorders: CD vs OD definitions with domain examples

    • MMSE as a quick cognitive screen and its scoring domains

  • Practical tips for exam preparation

    • Memorize key receptor types and their functions; distinguish extero-, intero-, proprioceptors

    • Be familiar with the Semmes-Weinstein filament thresholds and interpretation mapping

    • Understand the difference between feed-forward and feedback control and be able to explain with a movement example (e.g., skiing, brushing teeth)

    • Know common visuoperceptual and cognitive deficits in clinical presentations (e.g., agnosia, apraxia, aphasia, neglect, memory issues)

    • Practice interpreting short clinical scenarios to determine likely deficits and potential compensatory strategies

  • Notes on formatting for exam use

    • Use bullet-point summaries to capture definitions, test names, interpretations, and clinical implications

    • Include example scenarios to illustrate concepts (e.g., brushing teeth, dressing struggles, posture during transfers)

    • Remember to connect sensory deficits to occupational opportunities and ADL performance