NEUROLO

GIC

EVALU

ATION

EXAMINATIO

N OF

SENSORY

FUNCTION

CHAPTER 3

“In all higher order motor behaviors, the brain must correlate sensory inputs with motor outputs to accurately assess and control the body’s interaction with the environment.”

A. Jean Ayers, PhD

SENSORY INTEGRATION

• is the ability of the brain to organize, interpret, and use sensory information.

• Provides an internal representation of the environment

• Provide the foundation on which motor programs for purposeful movements are planned, coordinated, and implemented.

SENSORY INTEGRATION

“the neurological process that organizes sensation from one’s own body and from the environment and makes it possible to use the body effectively within the environment.”

developed by A. Jean Ayers (1920–1989)

SENSORY INTEGRITYSOMATOSENSATION (SOMATOSENSORY) refers to sensation received from the skin

and musculoskeletal system

SENSORY EXAMINATION OF SENSORY INTEGRITYBy determining the patient’s ability to

interpret and discriminate among incoming sensory information.

SENSORY INTEGRITY

The Guide to Physical Therapist Practice definition: “the intactness of cortical sensory processing, including proprioception,

pallesthesia, stereognosis, and topognosis.”

SENSATION AND MOVEMENT

Feedback control uses sensory information received during the movement to monitor and adjust output.

Feedforward control is a proactive strategy that uses sensory information obtained from experience.

SENSATION AND MOVEMENTThe primary role of sensation in movement is to: (1) guide selection of motor responses for

effective interaction with the environment(2) adapt movements and shape motor

programs through feedback for corrective action.

Sensation also provides the important function of protecting the organism from injury.

SENSORY DYSFUNCTION • Nerve damage• Metabolic disturbances (diabetes,

hypothyroidism, alcoholism);• Infections (Lyme disease, leprosy, human

immunodeficiency virus [HIV]);• Impingement or compression (arthritis, CTS); • Burns; • Toxins (lead, mercury, chemotherapy);• Nutritional deficits (vitamin B12). • SCI, CVA, TIA, tumors, multiple sclerosis (MS),

TBI

AGE-RELATED SENSORY CHANGES• Neurons are replaced at a declining rate• Degeneration of neurons• Decrease in the number of enzymes• Depletion of the neuronal dendrites• Gradual reduction in conduction velocity of

sensory nerves• Reduction of Meissner's and Pacinian

corpuscles• Decrease in the distance between the

nodes of ranvier

CLASS

IFICATIO

N OF

THE S

ENSORY SYSTE

M

SENSORY RECEPTORS• AKA sensory nerve endings• At the distal end of an afferent nerve fiber• Once stimulated specific sensation• RECEPTOR SPECIFICITY• highly sensitive to the type of stimulus for which they were designed.

• This specificity of nerve fiber sensitivity to a single

modality of sensation is called the labeled line principle.

SENSORY RECEPTORS(1)SUPERFICIAL SENSATIONS

EXTERORECEPTORS receive stimuli from the external environment via the skin and subcutaneous tissue.

>> Pain, Temperature, Light touch and pressure(2) DEEP SENSATIONS

Proprioceptors receive stimuli from muscles, tendons, ligaments, joints, and fascia

>> Position sense and awareness of joints at rest, movement awareness (kinesthesia), and vibration.

(3) COMBINED (CORTICAL) SENSATIONSExteroceptive + Proprioceptive + intact function of cortical sensory association areas.

>> Stereognosis, Two-point Discrimination, Barognosis, Graphesthesia, Tactile Localization, Recognition Of Texture, Double Simultaneous Stimulation

TYPES OF SENSORY RECEPTORS

A. CUTANEOUS RECEPTORS1. Free Nerve Endings Found throughout the body. perception of pain, temperature, touch, pressure, tickle, and itch

2. Hair Follicle Endings (Hair End-Organs) Hair follicle + FNE sensitive to mechanical movement and touch.

3. Krause’s End-Bulb bulbous encapsulated nerve endings in the dermis and conjunctiva

of the eye function not clearly understood. They are believed to be low threshold mechanical receptors that

may play a contributing role in the perception of touch and pressure.

A. CUTANEOUS RECEPTORS4. Merkel’s Discs located below the epidermis in hairless smooth (glabrous) skin with a

high density in the fingertips. sensitive to low-intensity touch, as well as to the velocity of touch,

and respond to constant indentation of the skin (pressure). They provide for the ability to perceive continuous contact of objects

against the skin and are believed to play an important role in both two-point discrimination and localization of touch and contribute to recognition of texture.

5. Ruffini Endings Located in the deeper layers of the dermis, and in joint capsules and

assist with joint position sense. perception of touch and pressure slowly adapting and particularly important in signaling continuous

skin deformation such as tension or stretch

A. CUTANEOUS RECEPTORS6. Meissner’s Corpuscles low-threshold, rapidly adapting and in high concentration in the

fingertips, lips, and toes, areas that require high levels of discrimination located at dermis.

These receptors play an important role in discriminative touch (e.g., recognition of texture) and movement of objects over skin.

7. Pacinian Corpuscles located in the subcutaneous tissue layer of the skin and in deep

tissues of the body (including tendons and soft tissues around joints).

stimulated by rapid movement of tissue and are quickly adapting. Perception of deep touch and vibration.

B. DEEP SENSORY RECEPTORS located in muscles, tendons, and joints and

include both muscle and joint receptors. They are concerned primarily with posture,

position sense, proprioception, muscle tone, and speed and direction of movement.

The deep sensory receptors include the muscle spindle, Golgi tendon organs, free nerve endings, Pacinian corpuscles, and joint receptors.

B1. MUSCLE RECEPTORS1. Muscle Spindles The muscle spindle fibers (intrafusal fibers) lie in a parallel arrangement to the

muscle fibers (extrafusal fibers). They monitor changes in muscle length (Ia and II spindle afferent endings) as

well as velocity (Ia ending) of these changes. plays a vital role in position and movement sense and in motor learning.2. Golgi Tendon Organs located in series at both the proximal and distal tendinous insertions of the

muscle. monitor tension within the muscle. provide a protective mechanism by preventing structural damage to the

muscle in situations of extreme tension. by inhibition of the contracting muscle and facilitation of the antagonist.

3. Free Nerve Endings These receptors are within the fascia of the muscle respond to pain and pressure.4. Pacinian Corpuscles Located within the fascia of the muscle, these receptors respond to vibratory

stimuli and deep pressure.

B2. JOINT RECEPTORS1. Golgi-Type Endings These receptors are located in the ligaments, and function to detect

the rate of joint movement.

2. Free Nerve Endings Found in the joint capsule and ligaments, these receptors are

believed to respond to pain and crude awareness of joint motion.

3. Ruffini Endings Located in the joint capsule and ligaments, Ruffini endings are

responsible for the direction and velocity of joint movement.

4. Paciniform Endings These receptors are found in the joint capsule and primarily monitor

rapid joint movements.

SPINAL PATHWAYSANTEROLATERAL SPINOTHALAMIC

Responds to stimuli that are potentially harmful in nature.

(+) slow-conducting fibers of small diameter, some of which are unmyelinated.

thermal and nociceptive information Mediates NONDISCRIMINATIVE SENSATIONS:

PainTemperatureCrudely localized touchTickleItchSexual sensations

SPINAL PATHWAYSANTEROLATERAL SPINOTHALAMIC Activated primarily by:

Mechanoreceptors Thermoreceptors Nociceptors

3 MAJOR TRACTS OF ST SYSTEM:ANTERIOR STT – Crude touch and

pressureLATERAL STT – Pain and temperature SPINORETICULAR TRACT – with diffuse

pain sensations

SPINAL PATHWAYSDORSAL COLUMN–MEDIAL LEMNISCAL

SYSTEM Responses to more discriminative

sensations from specialized mechanoreceptors

(+) fast-conducting fibers of large diameter with greater myelination

thermal and nociceptive information

Mediates:Discriminative touch and pressure

sensations Stereognosis Barognosis Graphesthesia Recognition of texture Two-point discriminationVibration Movement Position sense Awareness of joints at rest

FEATURES OF PATHWAYS FOR TRANSMISSION OF SOMATIC SENSORY SIGNALS

SOMATOSENSORY CORTEX

1.Primary somatosensory cortex (S-I)

2.Secondary somatosensory cortex (S-II)

3.Posterior parietal cortex

S1 NEURONS POSTCENTRAL GYRUS identify the location of stimuli as well as discern the size,

shape, and texture of objects.

S-II Superior aspect of the lateral sulcus innervated by neurons from S-I.

POSTERIOR PARIETAL LOBEBehind S1, Consists of Area 5,7Area 5 - integrates tactile input from mechanoreceptors of the

skin with proprioceptive input from muscles and joints. Area 7 - integrates stereognostic and visual information from

visual, tactile, and proprioceptive input.

BRODMANN’S AREA (47 AREAS)PARIETAL LOBE

BRODMANN

AREASGYRUR

S NAME FUNCTION LESION

Area 3,1,2 Post-central gyrus

Primary Somesthetic

Area

Proprioceptive and tactile

sensation

Hemianesthesia, Pain, temperature

and touch

Area 43 Gustatory Area Taste Difficulty identifying taste

Area 5,7 Superior Parietal

Secondary Somesthetic

Area

Interprets proprioceptive and tactile

sensation

Difficulty interpreting sensations

Area 40

Inferior Parietal Gyrus

SupramarginalSpeech

language processing

L: Ideomotor Apraxia

Area 39 AngularInitial

processing of written visual

language

Gerstman SyndromeCannot make meaning out of visually perceived words

BRODMANN’S AREA (47 AREAS)FRONTAL LOBE

BRODMANN AREAS GYRURS NAME FUNCTION LESION

Area 4 Precentral Gyrus Primary Motor Area Voluntary

movementWeakness

(flaccid/spastic)

Area 6Superior Frontal Gyrus

Pre-motor Area/ Motor Association

Area

PlanningInitiation of

motor movementCoordination

R: Problem in planning and initiation

L: Incoordination

Area 8 Frontal Eye FieldConjugate Eye

movementsCL Head and Eye

turning

R frontal eye field, affected pt turns head and eye toward the R

Area 9-12

Inferior Frontal Gyrus

Prefrontal Areas

IntelligencePersonalityBehaviorInsight

Judgment and Decision-making

Area 44Primary Motor

Speech “Broca’s Area”

Fluency

Flow of speech is slowand hesitant, vocabulary is limited, and syntax is impaired.Speech production is labored or lost completely

CLASSIFICATION OF APHASIA

FLUENCY GOOD POOR

COMPREHENSION GOOD POOR GOOD POOR

REPETITION G P G P G P G P

TERMINOLOGIES

ANOMIC

CONDUCTION

TRANSCORTICAL SENSORY

WERNICKE’S

TRANSCORTICAL MOTO

R

BROCA’S TRANSCORTICAL MIXED GLOBAL

BRODMANN’S AREA (47 AREAS)TEMPORAL LOBE

BRODMANN AREAS GYRURS NAME FUNCTION LESION

Area 41Superior Temporal

gyrus

Primary Auditory Area

Auditory input

Unilateral: partial deafness

Bilateral: Cortical deafness

Area 22,42

Secondary Auditory Area/

Auditory Association/

Wernicke’s Area

Interprets sound and

speech comprehensi

on

R – Auditory AgnosiaL – Aphasia: Fluent/ Sensory/ Posterior/ ReceptiveOCCIPITAL LOBE

BRODMANN

AREASGYRUR

S NAME FUNCTION LESION

Area 17

CuneusLingual

Primary Visual Area Visual Input

Unilateral: CL Homonymous Hemianpsia

Bilateral: Cortical blindness

Area 18-19 Secondary Visual Area

Interpretation of Visual

Input

18: color blindness/ color agnosia/

dyschromatopsia; alexia s agraphia

18-19: Visual Agnosia

PATTERN (DISTRIBUTION) OF SENSORY IMPAIRMENT

Dermatome (or skin segment) refers to the skin area supplied by one dorsal root.* Dermatome map

PRELIMINARY TESTS

2 GENERAL CATEGORIES:(1)Arousal level, attention span,

orientation, and cognition(2) Memory, hearing, and visual acuity

Arousal is the physiological readiness of the human system for activityLEVEL OF

CONSCIOUSNESS

PATIENT'S AROUSAL

LEVEL

LEVEL OF STIMULATIO

N INTERACTION WITH PT DIFFICULTY

Alert. Awake and attentive Normal Normal and

appropriate

Lethargic.

Drowsy and may fall

asleep if not stimulated in

some way

Should be stimulated in

some wayMay get diverted

in focusing or maintaining

attentionon a question

or task.

Obtunded. Somnolent state Repeated

Maybe largely

unproductiveConfused

when awake

Stupor (semicoma).

returns to theunconscious state when

stimulation is stopped

strong, generally noxious stimuli

Unable

Coma (deep coma).

cannot be aroused

by any type of stimulation

Reflex motor responses

may or may not be seen.

Attention is selective awareness of the environment or responsiveness to a stimulus or task without being distracted by other stimuli.

REPEAT ITEMSrepeat a series of numbers, letters, or words.begin with 2 or 3 items and gradually progress to longer lists.

SPELL WORDS BACKWARDSlonger words

Attention deficits will be apparent when the order of letters is confused or inability/ difficulty to perform tasks

Orientation refers to the patient’s awareness of time, person, and place.

“oriented × 3,” (T,P,P)

Partial orientation: domains of disorientation within parentheses.“oriented × 2 (time)”

“oriented × 1 (time, place).”

Cognition is defined as the process of knowing and includes both awareness and judgment

Fund of knowledge – sum total of an individual’s learning and experience in life

Calculation ability – examines foundational mathematical abilities; verbal or written•Acalculia – inability to calculate•Dyscalculia – difficulty in accomplishing calculations

Proverb interpretation – the patient’s ability to interpret use of words outside of their usual context or meaning.

FUND OF KNOWLEDGE:• Who became president after Kennedy was shot?• Who is the current vice president of the United

States?• Which is more—a gallon or a liter?• In what country is the Great Pyramid?CALCULATION ABILITY:4 + 4 = ____; 10 + 22 = ____; 46 × 8 = ____; 13 × 7

= ____; 4 × 3 = ____; 6 × 6 = ____; and so forth.).SAMPLE PROVERBS• People who live in glass houses shouldn’t throw

stones.• The early bird catches the worm.• The empty wagon makes the most noise.

MEMORYLong-term (remote) memory• date and place of birth,• number of siblings, • date of marriage, • schools attended, and • historical factsShort-term memory

PT provides series of words or numbers; pt will repeat sequence immediately.

• “car, book, cup”• Seven-digit number• Short sentence

Normal memory function should be able to recall the list 5 minutes later and at least two of the items from the list after 30 minutes.

• RECALL : ALL ITEMS 5 MINS AFTER

• REPEAT 2 ITEMS AFTER 3O MINS

HEARING

Observing the patient’s response to conversation can provide a gross assessment of hearing.

Note should be made of how alterations in voice volume and tone influence patient response.

VISUAL ACUITYPt wear corrective lensesDx that directly affect vision such as multiple sclerosis, hypertension, and diabetes.- standard Snellen chart mounted on the

wall- recorded at 20 feet (6 m) from the

Snellen chart- N: 20/20

- visual acuity cards for use at bedside.

Peripheral field visionDepth perception

SCREENING

FUNCTION OF SCREENING:• Determine the need for further or more

detailed examination• Determine in a timely manner if referral to

another health care practitioner is warranted• Focus the search for the origin of symptoms

to a specific location or body part• Identify system-related impairments that

contribute to activity limitations or disability

EQUIPMENTSENSATION EQUIPMENT1. PAIN Large-headed safety pin

Large paper clip that has one segment bent open

2. TEMPERATURE Two standard laboratory test tubes with stoppers.

3. LIGHT TOUCH A camel-hair brush, a piece of cotton, or a tissue.

4. VIBRATION Tuning fork and earphones5. STEREOGNOSIS (OBJECT RECOGNITION)

A variety of small, commonly used articles such as a comb, fork, paper clip, key, marble, coin, pencil, and so forth.

6. TWO-POINT DISCRIMINATION

two-point discrimination aesthesiometer

7. TEXTURE RECOGNITION Samples of fabrics of varioustexture such as cotton, wool, burlap, or silk

NEUROLOGIC PIN

PATIENT PREPARATION1. Explain purpose2. Cooperation is necessary3. Try not to guess4. Pt should be well rested5. Do demonstration6. Occlude patient’s vision using Blindfold/ folder

THE SENSORY EXAMINATIONThe superficial (exteroceptive) sensations are usually examined

first deep combined corticalDistal to proximal

• The modality tested • The quantity of involvement or body surface areas affected

(pattern identification)• The degree or severity of involvement (e.g., absent, impaired, or

delayed responses)• Localization of the exact boundaries of the sensory impairment• The patient’s subjective feelings about changes in sensation• The potential impact of sensory loss on function (i.e., activity

limitation, disability)

COMMON ELEMENTS OF SENSORYEXAMINATION FORMS(1)a dermatome chart to graphically display findings; (2)a grading scale

0—absent;1—impaired; 2—normal; NT—not testable

(3) a section for narrative comments

SOME THINGS TO REMEMBER:1. Hands should always be washed prior to and after

patient contact.2. Random pattern3. Varied timing4. Consider skin condition

SUPERFIC

IAL

SENSATIO

NS

PAIN PERCEPTION• sharp/dull discrimination• indicates function of protective sensation.• STIMULI: Not too close not too rapid• Maintain UNIFORM PRESSURE: with each successive

application of stimuli, the pin or reshaped paper clip should be held firmly and the fingers allowed to “slide” down the pin or paper clip once in contact with the skin.

ResponseThe patient is asked to verbally indicate sharp or dull when a

stimulus is felt. All areas of the body may be tested.

TEMPERATURE AWARENESS• ability to distinguish between warm and cool stimuli.• Two test tubes with stoppers• Cold are between 41°F (5°C) and 50°F (10°C) • Warmth, between 104°F (40°C) and 113°F (45°C).

The side of the test tube should be placed in contact with the skinThe test tubes are randomly placed in contact with the skin area to

be tested.

ResponseThe patient is asked to reply hot or cold after each stimulus

application

TOUCH AWARENESS• determines perception of tactile touch input.• A camel-hair brush, piece of cotton (ball or swab), or tissue

is used. The area to be tested is lightly touched or stroked.

ResponseThe patient is asked to indicate when he or she recognizes

that a stimulus has been applied by responding “yes” or “no.”

can be obtained by dividing the number of correct responses by the number of stimuli

PRESSURE PERCEPTION• fingertip or a double-tipped cotton swab is used

to apply a firm pressure on the skin surface• FIRM ENOUGH to indent skin

ResponseThe patient is asked to indicate when he or she

recognizes that a stimulus has been applied by responding “yes” or “no.”

DEEP SENSATIONS• Kinesthesia is the awareness of movement. • Proprioception includes position sense and

the awareness of joints at rest. • Vibration refers to the ability to perceive

rapidly oscillating or vibratory stimuli

KINESTHESIA AWARENESS• The extremity or joint(s) is moved passively through a relatively

small range of motion (ROM). • Small increments in ROM are used as joint receptors fire at specific

points throughout the range. • The therapist should identify the range of movement being examine

ResponseThe patient is asked to describe verbally the direction (up, down, in,

out, and so forth) and range of movement in terms previously discussed with the therapist while the extremity is in motion.

Or simultaneously duplicating the movement with the contralateral extremity.

PROPRIOCEPTIVE AWARENESS

The extremity or joint(s) is moved through a ROM and held in a static position. Again, small increments of range are used.

ResponseWhile the extremity or joint(s) is held in a static position

by the therapist, the patient is asked to describe the position verbally or to duplicate the position of the extremity or joint(s) with the contralateral extremity (position matching)

VIBRATION PERCEPTION• tuning fork that vibrates at 128 Hz.• Ability to perceive a vibratory stimulus is tested by

placing the base of a vibrating tuning fork on a bony prominence (such as the sternum, elbow, or ankle).

ResponseThe patient is asked to respond by verbally identifying or

otherwise indicating if the stimulus is vibrating or on-vibrating each time the fork makes contact.

COMBINED CORTICAL SENSATIONS1. Stereognosis Perception2. Tactile Localization3. Two-Point Discrimination4. Double Simultaneous Stimulation5. Graphesthesia (Traced Figure Identification)6. Recognition of Texture7. Barognosis (Recognition of Weight)

1. STEREOGNOSIS PERCEPTION• This test determines the ability to recognize the form of

objects by touch (stereognosis).• A variety of small, easily obtainable, and culturally familiar

objects of differing size and shape are required (e.g., keys, coins, combs, safety pins, pencils, and so forth).

ResponseThe patient is asked to name the object verbally. For patients

with speech impairments, sensory testing shields can be used

2. TACTILE LOCALIZATION• This test determines the ability to localize touch

sensation on the skin (topognosis). • The patient is asked to identify the specific point of

application of a touch stimulus (e.g., tip of ring finger, lateral malleus, and so forth) and not simply the perception of being touched.

ResponseThe patient is asked to identify the location of the stimuli by

pointing to the area or by verbal description. The patient’s eyes may be open during the response component of this test. The distance between the application of the stimulus and the site indicated by the patient can be measured and recorded.

3. TWO-POINT DISCRIMINATION• This test determines the ability to perceive two points

applied to the skin simultaneously. • It is a measure of the smallest distance between two

stimuli (applied simultaneously and with equal pressure) that can still be perceived as two distinct stimuli.

• As this sensory function is most refined in the distal upper extremities, this is the typical site for testing

3. TWO-POINT DISCRIMINATION• During the test procedure the two tips of the

instrument are applied to the skin simultaneously with tips spread apart.

• To increase the validity of the test, it is appropriate to alternate the application of two stimuli with the random application of only a single stimulus (the purpose of the third tip on some aesthesiometers).

• With each successive application, the two tips are gradually brought closer together until the stimuli are perceived as one.

ResponseThe patient is asked to identify the perception of “one”

or “two” stimuli.

4. DOUBLE SIMULTANEOUS STIMULATION• This test determines the ability to perceive simultaneous

touch stimuli (double simultaneous stimulation [DSS]).(1) identical locations on opposite sides of the body, (2) proximally and distally on opposite sides of the body, and/or (3) (3) proximal and distal locations on the same side of the

body.

ResponseThe patient verbally states when he or she perceives a touch

stimulus and the number of stimuli felt.

5. GRAPHESTHESIA (TRACED FIGURE IDENTIFICATION)

• This test determines the ability to recognize letters, numbers, or designs “written” on the skin.

• Using a fingertip or the eraser end of a pencil, a series of letters, numbers, or shapes is traced on the palm of the patient’s hand

• Orientation • Between each separate drawing the palm should be gently wiped

with a soft cloth to clearly indicate a change in figures to the patient.

ResponseThe patient is asked to identify verbally the figures drawn on the skin.

For patients with speech or language impairments, the figures can be selected (pointed to) from a series of line drawings.

6. RECOGNITION OF TEXTURE• This. test determines the ability to differentiate among

various textures. • Suitable textures may include cotton, wool, burlap, or silk.

The items are placed individually in the patient’s hand. • The patient is allowed to manipulate the sample textureResponseThe patient is asked to identify the individual textures as they

are placed in the hand. They may be identified by name (e.g., silk, cotton) or by texture (e.g., rough, smooth).

7. BAROGNOSIS (RECOGNITION OF WEIGHT)• This test determines the ability to recognize different weights. A

set of discrimination weights consisting of small objects of the same size and shape but of graduated weight is used

• The therapist may choose to place a series of different weights in the same hand one at a time, place a different weight in each hand simultaneously, or ask the patient to use a fingertip grip to pick up each weight.

ResponseThe patient is asked to identify the comparative weight of objects

in a series (i.e., to compare the relative weight of the object with the previous one); or when the objects are placed (or picked up) in both hands simultaneously the patient is asked to compare the weight of the two objects. The patient responds by indicating that the object is “heavier” or “lighter.”