I BOT_FOT I_Sensation_Dr. Punita V. Solanki_April 2024.pdf

First (I) Year BOT. Subject/Course: Fundamentals of Occupational Therapy I
S. No. 8: Definition, Classification, Variation in Testing Methods of Sensation
Lecture Notes by Dr. Punita V. Solanki. Professor & Incharge. April 2024
DYPU School of Occupational Therapy Nerul, Navi Mumbai. Dr. Punita V. Solanki Page 1 of 19
Course Syllabus: D Y Patil Deemed to be University School of Occupational Therapy
Bachelors of Occupational Therapy (BOT) Program 2021-2022
Year: First (I) Year BOT
Subject/Course: Fundamentals of Occupational Therapy I
Section (S. No.) 8 Contents (Level 3) (02 Hours)
8: Definition, Classification, Variation in Testing Methods of iii. Sensation
References
1. Willard and Spackman's Occupational Therapy by Elizabeth Blesedell Crepeau, Ellen S.
Cohn and Barbara A Boyt Schell. 11th
Edition 2009 (Unit XI: OT Evaluation and
Intervention: Personal Factors. Chapter 58. Sensation and Sensory Processing) and 13th
Edition 2019.
2. Occupational Therapy for Physical Dysfunction. Catherine A. Trombly, Mary Vining
Radomski. 5th
Edition 2002 & 7th
Edition 2014. Section II Assessment of Occupational
Function: 9 Assessing Abilities and Capacities: Sensation. Page 276.
3. Occupational Therapy: Practice Skills for Physical Dysfunction. Lorraine Williams
Pedretti, Mary Beth Early. 5th
Edition 2001 & 7th
Edition 2013 (Part IV: Performance Skills
and Client Factors: Evaluation and Intervention. Chapter 23. Evaluation of Sensation and
Intervention for Sensory Dysfunction. Page 575-589.) & 8th
Edition 2018.
4. Clinical Methods: The History, Physical, and Laboratory Examinations. Walker HK, Hall
WD, Hurst JW, editors. Boston: Butterworths; 3rd
Edition. 1990. Chapter 67. Sensation.
5. Guyton and Hall Textbook of Medical Physiology by John E. Hall and Arthur C. Guyton.
12th
Edition. 2011. Saunders.
I. Definition of Sensation
Sensation (also called sensibility) is a body function, a component of the client factors that
influences both the motor and processing aspects of performance skills.
The American Occupational Therapy Association (AOTA) defines sensory-perceptual skills
as “actions or behaviours” a client uses to locate, identify, and respond to sensations,
interpret, organize, and remember sensory events via sensations that include visual, auditory,
proprioceptive, tactile, olfactory, gustatory, and vestibular sensations.”

Sensation, in neurology and psychology, is any concrete, conscious experience resulting
from stimulation of a specific sense organ, sensory nerve, or sensory area in the brain.
(https://www.britannica.com/topic/sensation)
Sensation: is the process or experience of perceiving through the senses (American
Psychology Association (APA) Dictionary of Psychology)
Sensation: In medicine and physiology, sensation refers to the registration of an incoming
(afferent) nerve impulse in that part of the brain called the sensorium, which is capable of
such perception. Therefore, the awareness of a stimulus as a result of its perception by
sensory receptors.
Somatosensory System: The somatosensory system handles sensory input from superficial
sources such as the skin and from deep sources such as the musculoskeletal system. Sensation
is stimulated by receptors in the periphery of the body, and the sensory information then
travels to the brain by way of the spinal cord.
II. Classification of Somatosensory Receptors
Somatosensory receptors are specialized to respond to stimulation of a specific nature. These
receptors are categorized as
1. Mechanoreceptors: Mechanoreceptors respond to touch, pressure, stretch, and
vibration and are stimulated by mechanical deformation.
2. Chemoreceptors: Chemoreceptors respond to cell injury or damage and are stimulated by
substances that the injured cells release.
3. Thermoreceptors: Thermoreceptors respond to the stimulation of heating or cooling.
Each of these three types of receptors has a subset called nociceptors, which sense pain when
stimulated.
III. Classification of Sensations
I. Exteroceptive Sensation (also termed Superficial Sensation or Cutaneous Sensation):
receptors in skin and mucous membranes
1. Tactile or Touch Sensation (Thigmesthesia):
Touch sensation generally results from stimulation of tactile receptors in the skin or in tissues
immediately beneath the skin.
Disturbances in tactile or touch sensation are classified as:

a. Anaesthesia: absence of touch appreciation
b. Hypoesthesia: decrease of touch appreciation
c. Hyperesthesia: exaggeration of touch sensation, which is often unpleasant
2. Pressure Sensation
Pressure sensation generally results from deformation of deeper tissues to the skin.
3. Pain Sensation (Algesia):
Pain is an unpleasant sensory and perceptual experience that is associated with either actual
or potential cellular damage. The experience of pain is subjective and multidimensional.
Disturbances in pain sensation are classified as:
a. Analgesia: absence of pain appreciation.
b. Hypoalgesia: decrease of pain appreciation.
c. Hyperalgesia: exaggeration of pain appreciation, which is often unpleasant.
d. Allodynia: is defined as pain due to a stimulus that does not normally provoke pain.
4. Temperature Sensation: (Thermesthesia):
Temperature awareness is a test for protective sensation. Thermal receptors detect warmth
and cold.
Disturbances in temperature sensation are classified as:
a. Thermanalgesia: absence of temperature appreciation.
b. Thermhypesthesia: decrease of temperature appreciation.
c. Thermhyperesthesia: exaggeration of temperature sensation, which is often unpleasant.
II. Proprioceptive Sensation (also termed Deep Sensation): receptors located in muscles,
tendons, ligaments and joints.
Conscious proprioception derives from receptors found in muscles, tendons, and joints and
is defined as awareness of joint position in space. It is through cerebral integration of
information about touch and proprioception that objects can be identified by tactile cues and
pressure. If proprioception is impaired, it may be difficult to gauge how much pressure to use
when holding a paper cup.
a. Joint Position Sense: (Arthresthesia)

b. Vibratory Sense: (Pallesthesia) vibration sensation results from rapidly repetitive sensory
signals, but some of the same types of receptors as those for touch and pressure are used.
c. Kinesthesia: perception of muscular motion.
The term kinesthesia is sometimes used interchangeably with the term proprioception but can
also be defined as awareness of joint movement.
III. Cortical Sensory Functions: interpretative sensory functions that require analysis of
individual sensory modalities by the parietal lobes to provide discrimination. Individual
sensory modalities must be intact to measure cortical sensation.
a. Stereognosis: ability to recognize and identify objects by feeling them. The absence of
this ability is termed astereognosis.
b. Graphesthesia: ability to recognize symbols written on the skin. The absence of this
ability is termed graphanesthesia.
c. Two-Point Discrimination: ability to recognize simultaneous stimulation by two blunt
points. Measured by the distance between the points required for recognition. Absence is
described as such.
d. Touch Localization (Topognosis): ability to localize stimuli to parts of the body.
Topagnosia is the absence of this ability.
e. Double Simultaneous Stimulation: ability to perceive a sensory stimulus when
corresponding areas on the opposite side of the body are stimulated simultaneously. Loss of
this ability is termed sensory extinction.
Sensory Perversions (Abnormal Sensations)
a. Paraesthesia: abnormal sensations perceived without specific stimulation. They may be
tactile, thermal or painful; episodic or constant.
b. Dysesthesia: painful sensations elicited by a nonpainful cutaneous stimulus such as a light
touch or gentle stroking over affected areas of the body. Sometimes referred to as hyperpathia
or hyperalgesia. Often perceived as an intense burning, dyesthesias may outlast the stimulus
by several seconds.

III. Neurophysiological Foundations of Tactile Sensation
Receptors for tactile sensation are present within skin, muscles, and joints. Each tactile
receptor is usually specialized for a single type of sensory stimulation such as touch,
temperature, or pain.
The variation in the number of sensory units in a given area of skin is called innervation
density. The face, hand, and fingers have high innervation densities. Areas with high
innervation density are highly sensitive and have a proportionately large representation area
within the somatosensory area of the cortex, the postcentral gyrus of the parietal lobe. Figure
shows the organization within the cortex of sensory receptors from various regions of the
body.
Figure 1: Sensory Areas of Cerebral Cortex
IV. Purposes of Sensory Evaluation
The purposes of sensory testing, as defined by Cooke (1991), are as follows:
1. Assess the type and extent of sensory loss
2. Evaluate and document sensory recovery
3. Assist in diagnosis
4. Determine impairment and functional limitation

5. Provide direction for occupational therapy intervention
6. Determine time to begin sensory re-education
7. Determine need for education to prevent injury during occupational functioning
8. Determine need for desensitization
Before considering sensory evaluation, therapists need a good understanding of the neural
structures responsible for sensation.
V. Principles of Sensory Testing
1. Choose an environment with minimal distractions.
2. Ensure that the patient is comfortable and relaxed.
3. Ensure that the patient can understand and produce spoken language. If the patient cannot,
modify testing procedures to ensure reliable communication.
4. Determine areas of the body to be tested.
5. Stabilize the limb or body part being tested.
6. Note any differences in skin thickness, calluses, and so on. Expect sensation to be
decreased in these areas.
7. State the instructions for the test.
8. Demonstrate the test stimulus on an area of skin with intact sensation while the patient
observes.
9. Ensure that the patient understands the instructions by eliciting the correct response to the
demonstration.
10. Occlude the patient’s vision for administration of the test. Place a screen or a file folder
between the patient’s face and area being tested, blindfold the patient, or ask the patient to
close his or her eyes.
11. Apply stimuli at irregular intervals or insert catch trials in which no stimulus is given.
12. Avoid giving inadvertent cues, such as auditory cues or facial expressions, during
stimulus application.
13. Carefully observe the correctness, confidence, and promptness of the responses.
14. Observe the patient for any discomfort relating to the stimuli that may signal
hypersensitivity (exaggerated or unpleasant sensation).
15. Ensure that the therapist who does the initial testing does any reassessment.

VI Sensory Evaluation: Testing Methods
1. Light Touch or Tactile Sensation and Pain Sensation are evaluated based on the
dermatome. A dermatome is the area of skin supplied by one spinal dorsal root and its spinal
nerve. The clinical scoring for the light touch sensation and pain sensation is done as per
American Spinal Injury Association (ASIA) impairment scale.
Figure 2: Typical Dermatome Distribution

Figure 3: ASIA Impairment Scale
Three-Point Scale for Sensory Scoring According to ASIA Impairment Scale
A three-point scale is used for sensory scoring:
0 = Absent
1 = Altered - Impaired or Partial Appreciation, including Hyperesthesia
2 = Normal or Intact - Similar as on the cheek (normal sensory areas of the body)
NT = Not Testable

Standardized Sensory Testing Techniques or Objective Methods of Evaluation for Touch
or Tactile Sensation include: Semmes-Weinstein Monofilaments OR Weinstein Enhanced
Sensory Test (WEST)
Figure 4: Tactile Evaluation by Semmes-Weinstein Monofilaments
Measure of Threshold of Light Touch Sensation
Test Instrument
Non-Standardized Tests: Cotton ball or swab, fingertip, pencil eraser
Standardized Tests: Semmes-Weinstein monofilaments OR Weinstein Enhanced Sensory
Test (WEST)
Stimulus (S) and Response (R)
Non-Standardized Tests
S: Light touch to a small area of the patient’s skin.
R: Patient says “yes” or makes agreed-upon nonverbal signal each time stimulus is felt.
Semmes-Weinstein
S: Begin testing with fi lament marked 2.83; hold filament perpendicular to skin, apply to
skin until filament bends. Apply in 1.5 seconds, and remove in 1.5 seconds. Repeat three
times at each testing site, using thicker fi laments if the patient does not perceive thin ones
(except for filaments marked >4.08, which are applied one time to each site).
R: Patient says, “yes” upon feeling the stimulus.
WEST
S: Patient is prompted to stimulus, and then filament is applied perpendicular to skin and held
for 1 second, then slowly lifted. Catch trials consisting of prompt without filament
applications are randomly inserted within test sequence.

R: Patient responds with “yes” or “no” to indicate whether stimulus was felt.
Scoring and Expected Results
Non-Standardized Tests
Score is number of correct responses in relation to number of applied stimuli. Expected score
is 100%.
Semmes-Weinstein
Score involves recording the number of the filament or the actual force of the thinnest
filament detected at least once in three trials; results are usually recorded according to a
standard color code using coloured pencils or markers and a diagram of the hand/limb
Normal touch threshold for adults is the perception of the filament marked 2.83 (force, 0.08
g) except for the sole of the foot, where the normal threshold is the filament marked 3.61
(force, 0.21 g).
WEST
Results are recorded according to the color of the filament. Normal touch threshold is
perception of the thinnest monofilament. There are two WEST devices, one for the hand and
another for the foot. The WEST is meant to be a quick screening tool of sensation. When
needing to track recovery, the Semmes-Weinstein is used.
Pain Evaluation
Pain can be tested by pinching the digit firmly or by pinprick. Intact pain sensation is
indicative of protective sensation. The pinprick test can be used to rule out a digital nerve
laceration. Be sure to use universal precautions.
Test for Pain (Protective Sensation)
Procedure
• Using a sterilized safety pin, assess the amount of pressure required to elicit a pain response
on the uninvolved hand. This is the amount of pressure that the examiner will use on the
involved side.
• Alternate randomly between the sharp and dull sides of the safety pin and ensure that each
spot has one sharp and one dull application.
Response
• The client indicates “sharp” or “dull” following application.
Scoring

Score is number of correct responses divided by number of stimuli. Expected score is 100%.
Correct responses to sharp stimuli indicate intact protective sensation; incorrect responses to
sharp stimuli indicate some awareness of pressure but absent protective sensation.
• A correct response to both sharp and dull indicates intact protective sensation.
• An incorrect response to both sharp and dull indicates absent protective sensation.
Figure 5: Pain Evaluation with Pin
Temperature Awareness Evaluation
Precaution: In the clinic, it is important to test temperature sensation before applying heat or
cold modalities to avoid burn injuries. Thermal receptors are also critical for a person to be
able to determine safe water temperature for bathing. A client who lacks temperature
awareness must learn compensatory strategies such as testing the water temperature with an
unaffected body part. Many clinicians use only the pinprick test as sufficient evidence of
protective sensation.
Test for Temperature Awareness (Protective Sensation)
Procedure
• Apply test tubes or metal cylinders filled with hot or cold fluid randomly to areas of the
involved hand
Response
• The client indicates “hot” or “cold” following application.
Scoring

Score is number of correct responses divided by number of stimuli. Normal response is
100%.
• A correct response to both cold and hot indicates intact temperature awareness.
• An incorrect response to either or both indicates impaired temperature awareness.
Figure 6: Test for Temperature Awareness
Test for Static Two-Point Discrimination
Procedure
• Use a device such as the Disk-Criminator or Boley gauge with blunt testing ends.
• Test only the fingertips because this is the primary area of the hand used for exploration of
objects.
• Begin with a distance of 5 mm between the testing points.
• Randomly test one or two points on the radial and ulnar aspects of each finger for 10
applications
• Pressure is applied lightly; stop just when the skin begins to blanch.
Response
• The client will respond “one” or “two” or “I don’t know” following application.
Scoring
• The client responds accurately to 7 of 10 applications at that number of millimeters of
distance between the two points.

Norms are as follows:
• 1 to 5 mm indicates normal static two-point discrimination.
• 6 to 10 mm indicates fair static two-point discrimination.
• 11 to 15 mm indicates poor static two-point discrimination.
• One point perceived indicates protective sensation only.
• No points perceived indicates an anesthetic area.
Figure 7: Tools used in two-point discrimination tests: Disk-Criminators (top) and an
aesthesiometer (bottom).
Test for Moving Two-Point Discrimination
Procedure
• Begin with distance of 8â•¯mm between points.
• Randomly select one or two points, and move proximal to distal on the distal phalanx
parallel to the longitudinal axis of the finger so that the adjacent digital nerve is not
stimulated
• The pressure applied is just enough for the client to appreciate the stimulus.
• If client responds accurately, decrease the distance between the points and repeat the
sequence until you find the smallest distance that the client can perceive accurately.
Response
• The client states “one,” “two,” or “I don’t know.”
Scoring
• The client responds accurately to 7 of 10 applications.
• 2 to 4 mm for ages 4 to 60 indicates normal moving two-point discrimination.
• 4 to 6 mm for ages 60 and older indicates normal moving two-point discrimination.

Test for Touch Pressure
Procedure
• Begin with monofilament 1.65.
• Apply the monofilament for 1 to 1.5 seconds at the pressure needed to bow the
monofilament (applied perpendicularly).
• Hold the pressure for 1 to 1.5 seconds.
• Lift the monofilament in 1 to 1.5 seconds.
• The proper amount of pressure is achieved when the filament bends.
• Repeat this three times in the same spot for monofilaments 1.65 to 4.08; monofilaments
higher than 4.08 are applied only once.
• Randomly select areas of the hand to test, and change the interval of time between the
application of monofilaments.
• If the client does not perceive the monofilament, proceed to the next (thicker) monofilament
and repeat the sequence until monofilament 6.65.
• If the client does perceive the monofilament, record this number on the hand grid and
proceed to the next area of the hand.
Response
• The client says “touch” when he feels the monofilament.
Scoring
• The client responds to at least one of the three applications of the monofilament.
• Green (1.65 to 2.83) indicates normal light touch.
• Blue (3.22 to 3.61) indicates diminished light touch.
• Purple (3.84 to 4.31) indicates diminished protective sensation.
• Red (4.56 to 6.65) indicates loss of protective sensation.
• Untestable indicates an inability to feel the largest monofilament.

Figure 8: Application of a touch pressure monofilament to the client’s fingertip.
Test for Proprioception
Joint Position Sense
Procedure
• Hold the lateral aspect of the elbow, wrist, or digit.
• Move the body part into flexion or extension
Response
• The client indicates whether the body part is being moved “up” or “down.”
Scoring
• An accurate response indicates intact proprioception. Graded as intact, impaired, or absent.
Usually, reproduction of position can be accomplished within a few degrees. One study of the
knee joint found on average 4° of error in normal subjects younger than age 30 years and 7°
of error in normal subjects older than age 60 years.
Kinesthesia is sometimes used interchangeably with the term proprioception but can also be
defined as awareness of joint movement. Some therapists make a distinction between these
two terms and test for kinesthesia by moving the unaffected limb into a certain posture and
having the client copy the movement with the affected side while the eyes are closed.
S: Hold body segment being tested on the lateral surfaces; move the part through angles of
varying degrees.
R: Patient indicates whether part is moved up or down.
Scoring

Graded as intact, impaired, or absent. Nearly 100% correct identification is expected.
Figure 9: Testing proprioception of the finger.
Stereognosis
Stereognosis is the use of both proprioceptive information and touch information to identify
an item with the vision occluded. Without stereognosis, it is impossible to pick out a specific
object such as a coin or a key from one’s pocket, use a zipper that fastens behind you, or pick
up a plate from a sink of sudsy water.
The Dellon modification of the Moberg Pickup Test is
a good test for stereognosis for clients with injuries involving the median and/or ulnar nerves.
This test requires the client to have the ability to participate motorically, so motor loss or
weakness should be factored into the choice of this assessment. This test is based on the
Moberg Pickup Test, which is a timed motor test that does not require identification of
objects.
Modified Pick-Up Test Dellon’s Modification of the Moberg Pick-Up Test measures
the interpretation of sensation in the distribution of the median nerve.
Test Instrument
A small box and 12 standard metal objects: wing nut, screw, key, nail, large nut, nickel, dime,
washer, safety pin, paper clip, small hex nut, and small square nut.

Part 1
S: Tape small and ring digits to palm to prevent use. With patient using vision, have him or
her pick up and place objects in a box as quickly as possible; time performance on two trials.
R: Patient picks up each object and deposits it in the box as quickly as possible.
Part 2
S: With patient’s vision occluded, place one object at a time between three-point pinch in
random order and measure speed of response.
R: Patient manipulates object and names it as rapidly as possible.
Part 1
Score is total time to pick up and place all 12 objects in the box for each of two trials
Normal response
Trial 1: 10-19 seconds
Trial 2: 9-16 seconds
Part 2
Score is time to recognize each object on each of two trials (up to a maximum of 30 seconds)
Normal response: 2 seconds per object.
Figure 10: Dellon Modification of the Moberg Pickup Test
Localization of Touch
Localization of touch is considered to be a test of functional sensation because there is high
correlation between this test and the test for two-point discrimination. Localization of touch is

an important test to perform following nerve repair since it helps determine the client’s
baseline and projected functional prognosis. This test can be done with a constant (static)
touch or a moving touch. Localization of touch is thought by many to reflect a cognitive
component of the client’s abilities. Because it is considered to be a test of tactile
discrimination that requires cortical processing, it is different from touch pressure testing.
Test for Localization of Touch
Procedure
• Apply the finest monofilament that the client can perceive to the center of a corresponding
zone on the hand grid.
• Once the client feels a touch, have him or her open his or her eyes and use the index finger
to point to the exact area where the stimulus was felt.
• Place a dot on the hand grid for a correct response.
• Place an arrow from the site of the actual stimulation to the identified site if the stimulus is
identified incorrectly.
Response
• The client attempts to identify the exact location of a stimulus.
Scoring
• Correct identification of the area within 1 cm of actual placement indicates intact touch
localization
Vibration Threshold
Measures threshold of rapidly adapting fibres.
Test Instrument
Vibrometer: biothesiometer, Vibratron II, automated tactile tester, Case IV System
Protocols vary with instrument
S: Generally, vibrating head is applied to area to be tested (especially bony prominences or
over the joint). Stimulus intensity is gradually increased or decreased
R: Patient indicates when vibration is first felt or no longer felt.
Scoring varies with instrument; norms usually provided by manufacturer.

Figure 11: Vibration Test with Vibrating Tuning Fork
Standardized Functional Sensory Testing Techniques / Scales
1. Erasmus MC Revised Nottingham Sensory Assessment: Quantitative functional
measure of sensation after stroke. Sensations assessed include: light touch, pinprick, pressure,
two-point discrimination, and proprioception.
2. Hand Active Sensation Test (HASTe): Quantitative functional measure of haptic
perception in the hand.
3. Quick DASH (Institute for Work & Health, 2006): Self-report tool for people with
musculoskeletal disorders of the upper extremities. Measures perceived abilities to do tasks
requiring sensory feedback.

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