sensory system examination OF PATIENT IN HOSPITAL

sENSORY SYSTEM EXAMINATION OF NERVOUS SYSTEM

1. Sensory System Examination Dr. Ananya Dubey PG 1 st Year MD Physiology

2. Learning Objectives Importance of performing this practical in clinical physiology. Classify different sensation. Elicit all the sensation. List precaution taken during elicitation of sensations.

3. General Points Each sensory discrimination procedure is tested with patient’s eyes closed Before starting the procedure explain the nature of the test to be performed Compare symmetric areas on the two sides of the body and ask the patient to compare perceived sensations, side to side Vary the pace of your testing so that the patient does not merely respond to your repetitive rhythm Map out the boundaries of an area of sensory loss or hypersensitivity. Stimulate first at a point of reduced sensation.

4. General Points Examination is done in this order: Superficial (Exteroceptive) sensation : Pain, Touch, Temperature, Pressure Proprioceptive (deep) sensation : Deep/Pressure Pain, Vibration, Joint position Combined cortical or discriminative sensations : Stereognosis, Tactile Localization, Two-Point Discrimination, Double Simultaneous Stimulation (Extinction), Graphesthesia, Barognosis Sensory tests are done from the distal to the proximal direction

5. General Points Knowledge of dermatomes helps you localize neurologic lesions to a specific level of the spinal cord, particularly in spinal cord injury. A dermatome is the band of skin innervated by the sensory root of a single spinal nerve Do not try to memorize all the dermatomes. Instead, focus on learning the dermatomes shaded in green

6. Exteroceptive Sensation

7. Light Touch With a fine wisp of cotton, touch the skin (non-hairy area) lightly, avoiding pressure. Ask the patient to respond whenever a touch is felt, and to compare one area with another. Tissue paper, or feather, or soft brush, or fingertip, or von Frey’s aesthesiometer can also be used.

8. Light Touch One of the less satisfactory modalities of sensation to test is light touch Tickle (stroking the skin) is a different modality; moving hairs on hairy skin is different again An abnormality of light touch sensation will not differentiate a posterior column lesion from one affecting the spinothalamic tracts Thigmesthesia : tactile sensibility. Anaphia : absence of sensibility to touch

9. Superficial Pain Use a sharp end of broken tooth pick (wooden), or other suitable tool like Neurotip . Occasionally, substitute the blunt end for the point. Ask the patient, “Is this sharp or dull?” or, when making comparisons, “Does this feel the same as this?” Apply the lightest pressure needed for the stimulus to feel sharp

10. Superficial Pain Superficial pain testing is more informative diagnostically Analgesia refers to absence of pain sensation, hypalgesia refers to decreased sensitivity to pain, hyperalgesia refers to increased pain sensitivity, and allodynia refers to pain due to a stimulus that does not usually provoke pain.

11. Temperature To evaluate temperature sensation, roll dry test tubes filled with warm (40°C to 45°C) and cold (5°C to 10°C) water against the skin, alternating in an unpredictable pattern between the various sites. Ask the patient to indicate which temperature is perceived and where it is felt Perception of heat and cold is often omitted if pain sensation is normal, as it adds little in routine clinical practice. In Leprosy temperature sense may be lost prior to pain sensation.

12. Pressure Pressure is sustained touch (Crude touch ? ) Pressure can be assessed using a 10-gram monofilament to apply a standard quantity of pressure, alternatively finger tip can be used. Object used should be at skin temperature of the subject to prevent temperature sensation This can be useful as a screening test in situations where a patient is at risk of development of sensory peripheral neuropathy (e.g. diabetes).

13. Proprioceptive Sensation

14. The proprioceptive sensations arise from the deeper tissues of the body, principally from the muscles, ligaments, bones, tendons, and joints. Proprioception refers to either the sense of position of a body part or motion of a body part. Proprioception has both a conscious and an unconscious component. The conscious component travels with the fibers subserving fine, discriminative touch; the unconscious component forms the spinocerebellar pathways.

15. Vibration ( Pallesthesia ) Apply the base of the vibrating 128 Hz tuning fork to bony parts of the limbs and ask the subject to report whether they feel the vibrations If you are not sure whether the subject is feeling vibration, ask the subject to tell you when the vibration stops. Then touch the tuning fork to stop it from vibrating and confirm this change with the subject. Vibration sense is often the first sensation lost in a peripheral neuropathy. Causes include diabetes, alcoholism, and posterior column disease, seen in tertiary syphilis or vitamin B12 deficiency.

16. Joint Position Sense (Arthresthesia) It is extremely helpful to instruct the patient, eyes open, about the responses expected before beginning the test With the thumb and index finger of one hand, hold each side of the middle phalanx of the subject’s middle finger. With your other hand, grasp the sides of the distal phalanx. Move the distal phalanx either up or down through a small angle; the patient should be able to perceive as small a movement as you will be able to make. Make sure each movement is random, not just up, down, up, down, etc.

17. Joint Position Sense Awareness of movement is known as kinesthesia Joint movement sense (kinesthesia) can be tested by asking a patient to report any movement of the finger or toe regardless of the direction of movement. Loss of position sense, like loss of vibration sense, is seen in tabes dorsalis, multiple sclerosis, or B12 deficiency from posterior column disease, and in diabetic neuropathy.

18. Joint Position Sense Pseudoathetosis : ask the patient to hold the hands outstretched while the eyes are closed. With severe loss of distal proprioception, the fingers move in an irregular, purposeless fashion, as if exploring their environment

19. Joint Position Sense Romberg’s test : ask the patient to stand with feet/heels close together, arms by the side, and the eyes closed for 30 to 60 seconds without support Where there is loss of proprioception, the patient immediately loses stability (positive Romberg’s test). Be ready to support the patient.

20. Deep Pressure Pain Pressure on deep structures (muscle masses, tendons, nerves), using finger pressure or a blunt object. Strong pressure over muscles, tendons, and nerves tests deep pain sensibility. Deep pain may be tested by squeezing muscles, tendons, or the testicles; by pressing on the eyeballs; by pushing a finger interphalangeal joint into extreme hyperflexion; or by applying firm pressure on the base of a nail. Abadie’s sign is the absence of pain on squeezing the Achilles tendon, which is normally quite uncomfortable..

21. Cortical Sensation

22. Stereognosis Place a familiar object such as a coin, paper clip, key, pencil, or cotton ball, in the patient’s hand and ask the patient to tell you what it is.

23. Graphesthesia With the blunt end of a pen or pencil, draw a large number in the patient’s palm. A normal person can identify most such numbers. The inability to identify the numbers is a sensitive sign of parietal lobe disease.

24. Two-Point Discrimination Using the two ends of an opened compass aesthesiometer with minimum distance of 1 mm, touch the skin of the subject lightly Ask the subject to say whether he is being touched by one or two points If the subject says one, increase the distance gradually till two separate points are appreciated by him. This is the minimum separable distance. Record the minimum separable distance on different parts of the body on both the sides.

25. Two-Point Discrimination Alternate the double stimulus irregularly with a one-point touch. Be careful not to cause pain. On the fingertips and toes, two points are commonly felt when 2 to 8 mm apart. A greater distance is expected for discrimination of two points on other body parts, such as the back (40 to 70 mm) or chest and forearms (40 mm).

26. Tactile localisation ( Topognosia ) Briefly touch a point on the patient’s skin. Then ask the patient to open both eyes and point to the place touched

27. Double simultaneous stimulation Simultaneously touch two areas on each side of the body Normally, patients have no problem identifying both areas. A patient with a lesion in the parietal lobe may feel the individual touches but may “extinguish” the sensation on the side contralateral to the side of the lesion. This is the phenomenon termed extinction .

28. Barognosis Baresthesia, ability to sense pressure or weight Barognosis : recognition and differentiation of weight, or the ability to differentiate between weights A set of discrimination weights consisting of small objects of the same size and shape but of graduated weights are used.

29. Few Terminologies Hypoesthesia is a decrease, and anesthesia an absence, of all sensation Hyperaesthesia – exaggerated response to the sensory stimulus Paresthesia is an abnormal sensation (without an apparent physical cause) Dysesthesia (Gr. dys “bad”) is an abnormal, unpleasant, or painful sensation

30. Sensation Upper Limb Lower Limb Right Left Right Left Touch Superficial Pain Cold Temperature Warm Temperature Pressure Vibration Joint Position Romberg Test Deep Pressure Pain Stereognosis Two point discrimination Tactile localisation Double simultaneous stimulation Graphesthesia

31. References Textbook of practical physiology -G K Pal Textbook of practical physiology- C L Ghai

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