3. • The term Somatosensation refers to sensation recieved
from the skin and musculoskeletal system as opposed to
that from specialized senses such as sight or hearing .
• Sensory information detected at peripheral receptors
,travel via peripheral nerves –nerve root -spinal cord-
brainstem – thalamus – sensory cortex.
• General sensation which include
touch,pain,temperature,proprioception and pressure
.Special senses –vision ,hearing ,taste and smell which
convey sensation to brain through cranial nerves.
• Pain and temperature sensation ( carried by small
unmyelinated fibres
• Vibration and proprioception (joint position,
Carried by large myelinated fibres ).
5. Schematic diagram to show a motor unit consisting of a
number of muscle fibres innervated by a single motor neuron
6.
7.
8. PATHWAY FOR TRANSMISSION OF
SOMATIC SENSORY SIGNALS :-
Somatic sensory information enters the spinal
cord through the dorsal roots. Sensory signals
are then carried to higher centers via ascending
pathway from one of two system :-
Anterolateral spinothalamic pathway :-
( pain and temperature )
Dorsal coloumn- medial lemniscal pathway :-
(discriminative sensation such as kinesthesia and
touch )
9.
10. Classification of sensory system
• Superficial Sensation:-
-Pain
-Touch
-Temperature
- Pressure Perception.
• Deep Sensation:-
-Kinesthesia awareness( movement)
-Proprioceptive awareness (joint position)
-Vibration perception
• Cortical Sensation :-
-Steregnosis perception -Two point discrimination
-Tactile localization - Double simultaneous stimulation
-Graphesthesia - Recognition of texture
-Barognosis
11. Somato Sensory Examination
• Prepration :-
- Testing enviornment:- should be administered in a quieter ,well
lit area, depending on a number of body areas to be tested,
either a sitting or recumbent position may be used .
• Equipment :-
1- Pain – a large headed safety pin ,paper clip.
2- Temperature – two standard laboratory test tubes with
stoppers .
3- light touch – camel hair brush , a peice of cotton
4- vibration- tunning fork
5- stereognosis – commonly known articles like cotton, gloves,
fork, keys,paper, coin, pencil
6-Two point discrimination – aesthesiometer
7-Recognition of texture – sample of fabrics cotton, wool, silk
12. Patient preparation :-
• A full explaination of the purpose of the testing
should be provided . The patient also should be
informed that cooperation is neccessary to
obtain accurate test result .
• During examination patient should be in a
comfortable ,relaxed position .
• Visual input is prevented because it may allow
for compensation of a sensory deficit and thus
decrease the accuracy of test result
13. key to Grading :-
0 - Absent
1 - Decreased ,Delayed Response
2 - Increased , Exaggerated Response
3 - Inconsistent Response
4 - Intact ,Normal Response
NT - Unable to Test
15. Superficial reflexes :-
• PAIN PERCEPTION :-
-Instrument – toothpick , large headed safety pin
-Instrument should be cleaned before administering
-Each dermatome is accessed to know the part of impairment .
-Response of the patient is noted verbally indicating sharp or dull .
-Grading is done according to the response .
• TEMPERATURE AWARENESS :-
-This test determine the ability to distinguish between warm and cool
stimuli . Two test tubes with stopper are required for this examination
one should be filled with warm water and the other with crushed ice
.Temperature for cold – 5degree C and 10 degree C
for warmth – 40 degree C and 45 degree C.
-Response of the patient is noted to reply hot or cold after each stimulus
application .
16. • TOUCH AWARENESS:-
-This test determines perception of tactile touch input .a
camel hair brush,a peice of cotton ,or tissue is used.
-The area to be tested is lightly touched or stroked .
-The patient is asked to indicate when he or she recognize
that a stimulus has been applied by responding yes or
no.
17. • PRESSURE PERCEPTION :-
-The therapist fingertip or a double tipped cotton swab is
used to apply a firm pressure on the skin surface.
-This test can also be administered using the thumb and
fingers to squeeze the achilles tendon.
-Response is asked to indicate when an applied stimulus
is recognized by responding ‘yes’ or ‘now
18.
19. DEEP SENSATIONS
• Kinesthesia awareness :-
-The test examine awareness of movement .
The extremity of joints is moved passively through
a relatively small range of motion .
-The therapist should identify the range of movement being examined.( initial, mid
or terminal )
-a trial run or demonstration of the procedure should be performed prior to actual
testing .
-this will ensure that the patient and the therapist agree on terms to describe the
direction of movements.
-The patient is asked verbally the direction ( up,down ,in,out and so forth)
-The patient may also respond by simultaneously duplicating the movement with the
contralateral extremity
20.
21. • PROPRIOCEPTIVE AWARENESS :-
-The test examines joint position sense and the
awareness of joints at rest .
-The extremity or joints is moved through a ROM and
held in a static position .
-caution should be used with hand placement to avoid
excessive tactile stimulation .
-The pateint is asked to respond verbally or to
duplicate the
position of the extremity with the contralateral
extremity.
22.
23. • VIBRATION PERCEPTION :-
- The test requires a tunning fork that vibrates 128 hz.
- Striking the tines briskly over hypothenar eminence
- The base of the tunning folk then placed on bony
prominence .
- If vibration sensation is intact ,the patient will perceive the
vibration, if there is impairment the patient will be unable
to distinguish between vibrating and non vibrating tunning
fork
24. COMBINED CORTICAL SENSATION
• Stereognosis perception :-
- The test determines the ability to recognize the form of objects by
touch .
- Variety of small ,easily available and culturally familiar objects of
differing size and shape are required. ( keys , button , ring , coin )
- The patient is asked to name the object verbally ,patient with
speech impairment ,sensory testing sheilds can be used .
25.
26. • Tactile localization :-
- The test determine the ability to localize touch sensation on the skin
.
- The patient is asked to identify the specific point of application of a
touch stimulus ( eg. Tip of ring finger , lateral malleolus )
- The patient is asked to identify the location of the stimuli by
pointing to the area or by verbal description .
- The distance between the application of the stimulus and the site
indicated by the patient can be measured .
• TWO POINT DISCRIMINATION :-
- The test determines the ability to percieve two points
applied to the skin . It is a measure of the smallest
distance between two stimuli that can still be percieved
as two distinct stimuli .
- The patient is asked to identify the perception of ‘one’ or
‘two’ stimuli.
27. • DOUBLE SIMULTANEOUS STIMULATION :-
- The test determine the ability to perceive simulataneous
touch stimuli .The
therapist simultaneously touches the :-
1- identical locations on opposite sides of body
2- proximal and distally opposite sides of the body
3- proximal and distal locations on the same side of the
body .
The term extinction phenomenon is used to describe a
situation in which only the proximal stimulus is
perceived with extinction of the distal.
28. • GRAPHESTHESIA (Traced finger identification ) :-
- The test determines the ability to recognize letters
,numbers or designs written on skin . Using a fingertip or
the eraser end of pencil
- The test is usually a substitue for stereognosis when
paralysis prevent grasping an object .
- The pateint is asked verbally to identify figures drawn on
skin
29.
30. RECOGNITION OF TEXTURE :-
- The test determines the ability to differentiate among various
textures.
- Suitable texture may include cotton , wool or silk .
- The items are placed individually in the patient’s hand ,and he or
she is allowed to manipulate the sample texture.
- The patient is asked to identify the indvidual textures as they are
placed in the hand .
BAROGNOSIS ( Recognition of weight ):-
- The test detrmines 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 patient is asked to identify the comparative weight of objects in
a series
- The patient responds by indicating that the object is ‘heavier’ or ‘
lighter ’ .
31. • TERMINOLOGY DESCRIBING SENSORY
IMPAIRMENT :-
Abarognosis – inability to recognize weight
Analgesia –complete loss of pain sensitivity
Hypalgesia – decreased sensitivity to pain
Hyperalgesia – increased sensitivity to pain
Hypersthesia – increased sensitivity to sensory
stimuli
Hypoesthesia – decreased sensitivity to sensory
stimuli
Thermanalgesia – inability to perceive heat .
