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Sensory system examination

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SENSORY SYSTEM EXAMINATION

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Sensory system examination

  1. 1. Sensory system examination Dr.A.P.P.Pavani PG in medicine
  2. 2. OVERVIEW  Introduction  Anatomy of sensation  Examination  Sensory localisation---patterns of sensory loss
  3. 3. INTRODUCTION  Sensory examination is the most difficult and tedious part of neurologic examination.  Requires great concentration and cooperation from the patient and from the examiner.  Inconsistency in patient’s replies may be due to fatigue, poor co-operation, dementia or undue suggestibility.  Examination needs to be goal directed; otherwise tends to be fruitless or misleading.  Sensory loss is of far greater importance in some conditions than in others as in suspected syringomyelia , or in searching for the level of a lesion causing a paraplegia, or in delineating a peripheral nerve lesion.
  4. 4. COMBINED OR CORTICAL SENSATIONSPRIMARY SENSATIONS MODALITIES OF SENSATIONS TO BE TESTED EXTROCEPTIVE PROPRIOCEPTIVE
  5. 5. PRIMARY SENSATIONS 1.Extroceptive sensations: Derived from sources outside the body  Light touch  Pain  Temperature 2.Proprioceptive sensations: Derived from body itself  Sense of position and passive movement  Vibration  Deep pressure pain
  6. 6. COMBINED AND CORTICAL SENSATIONS Require synthesis and interpretation of primary modalities by the sensory association area in the parietal lobe.  Stereognosis  Two point discrimination  Graphaesthesia  Barognosis  Localisation of touch(topognosis)
  7. 7. ANATOMY OF SENSATION POST CENTRAL CORTEX THALAMUS FIBRE TRACTS DORSAL HORN OF SPINAL CORD SENSORY AFFERENTS SENSORY RECEPTORS
  8. 8. ANATOMY OF SENSATION Sensory receptors are of two general types: EXTEROCEPTORS  Those in the skin, mediating superficial sensation.  Skin receptors are particularly numerous and transduce four types of sensory experience: warmth, cold, touch, and pain. PROPRIOCEPTORS  Those in the deeper somatic structures.  Proprioceptors inform us of the position of our body or parts of our body; of the force, direction, and range of movement of the joints (kinesthetic sense); and a sense of pressure, both painful and painless.
  9. 9. LOCATION AND MORPHOLOGY OF MECHANORECEPTORS IN HAIRY AND HAIRLESS SKIN OF THE HUMAN HAND
  10. 10. ANATOMY OF SENSATION SPINOTHALAMIC PATHWAY OR ANTEROLATERAL SYSTEM • The polysynaptic projections of the smaller fibers (unmyelinated and small myelinated), which subserve mainly nociception, itch, temperature sensibility, and touch, cross and ascend in the opposite anterior and lateral columns of the spinal cord, through the brainstem, to the ventral posterolateral (VPL) nucleus of the thalamus and ultimately project to the postcentral gyrus of the parietal cortex.
  11. 11. ANATOMY OF SENSATION POSTERIOR COLUMN–MEDIAL LEMNISCAL PATHWAY  The larger fibers,which subserve tactile and position sense and kinesthesia, project rostrally in the posterior and posterolateral columns on the same side of the spinal cord and make their first synapse in the gracile or cuneate nucleus of the lower medulla.  Axons of second-order neurons decussate and ascend in the medial lemniscus located medially in the medulla and in the tegmentum of the pons and midbrain and synapse in the VPL nucleus of thalamus.  Third-order neurons project to parietal cortex as well as to other cortical areas.
  12. 12. ANATOMY OF SENSATION  Although the fiber types and functions that make up the spinothalamic and lemniscal systems are relatively well known, many other fibers, particularly those associated with touch, pressure, and position sense, ascend in a diffusely distributed pattern both ipsilaterally and contralaterally in the anterolateral quadrants of the spinal cord.  This explains why a complete lesion of the posterior columns of the spinal cord may be associated with little sensory deficit on examination.
  13. 13. TRANSVERSE SECTION THROUGH THE SPINAL CORD, COMPOSITE REPRESENTATION, ILLUSTRATING THE PRINCIPAL ASCENDING (LEFT) AND DESCENDING (RIGHT) PATHWAYS..
  14. 14. THE "SENSORY HOMUNCULUS," OR CORTICAL REPRESENTATION OF SENSATION IN THE POSTCENTRAL GYRUS
  15. 15. SYMPTOMS • Before proceeding to sensory testing, the physician should question patients about their symptoms. • Abnormal sensory symptoms can be divided into two categories:  Positive symptoms.  Negative symptoms.
  16. 16. SYMPTOMS • The prototypical positive symptom is tingling (pins and needles); other positive sensory phenomena include itch and altered sensations that are described as pricking, bandlike, lightning like shooting feelings (lancinations), aching, knifelike, twisting, drawing,pulling, tightening, burning, searing, electrical, or raw feelings. • Such symptoms are often painful. • Because positive phenomena represent excessive activity in sensory pathways, they are not necessarily associated with a sensory deficit (loss) on examination.
  17. 17. SYMPTOMS • Negative phenomena represent loss of sensory function and are characterized by diminished or absent feeling that often is experienced as numbness and by abnormal findings on sensory examination. • Whereas sensory symptoms may be either positive or negative, sensory on examination are always a measure of negative phenomena.
  18. 18. TERMINOLOGY • Paresthesias and dysesthesias are general terms used to denote positive sensory symptoms. • The term paresthesias typically refers to tingling or pins-and-needles sensations but may include a wide variety of other abnormal sensations, except pain; it sometimes implies that the abnormal sensations are perceived spontaneously. • The more general term dysesthesias denotes all types of abnormal sensations, including painful ones, regardless of whether a stimulus is evident.
  19. 19. Another set of terms refers to sensory abnormalities found on examination. • Hypesthesia or hypoesthesia refers to a reduction of cutaneous sensation to a specific type of testing such as pressure, light touch, and warm or cold stimuli; • Anesthesia refers to a complete absence of skin sensation to the same stimuli plus pinprick. • Hypalgesia or analgesia to reduced or absent pain perception (nociception). • Hyperesthesia means pain or increased sensitivity in response to touch. • Allodynia describes the situation in which a non painful stimulus, once perceived, is experienced as painful, even excruciating. • Hyperalgesia denotes severe pain in response to a mildly noxious stimulus. • Hyperpathia, a broad term, encompasses all the phenomena described by hyperesthesia, allodynia, and hyperalgesia.
  20. 20. • Disorders of deep sensation arising from muscle spindles, tendons, and joints affect proprioception (position sense). • Manifestations include imbalance (particularly with eyes closed or in the dark), clumsiness of precision movements, and unsteadiness of gait, which are referred to collectively as sensory ataxia. • Other findings on examination, include reduced or absent joint position and vibratory sensibility and absent deep tendon reflexes in the affected limbs.
  21. 21. • Origin of aberrant sensations SYMPTOM STRUCTURES AFFECTED Paresthesia , tingling ,buzzing Large fibres(in nerve or posterior columns) Burning, heat , cold Small fibres Prickling pain Combined small and large fibre Band tightness Lemniscal system of the cord Lancinating pain Small fibre neuropathy and radiculopathy Hyperalgesia Partial peripheral nerve damage
  22. 22. EXAMINATION • OBJECTIVES  To demonstrate clearly and consistently the limits of any areas of abnormal sensation.  To determine which modalities are involved within those limits.  To compare the findings with known patterns of abnormal sensation.
  23. 23. EXAMINATION Questions to be posed while examining:  Is there a sensory loss at all?  Is there a sensory level and if yes , at what spinal segment?  Is there a graded sensory loss?
  24. 24. EXAMINATION EFFECT OF AGE ON SENSORY FUNCTION • A matter of importance in the testing o f sensation is the progressive impairment of sensory perception that occurs with advancing age. • This requires that sensory thresholds , particularly in the feet and legs, be assessed in relation to age standards. • The effect of aging is most evident in relation to vibratory sense, but proprioception, the perception of touch, and fast pain are also diminished with age. • It is probably caused by neuronal loss in dorsal root ganglia and are reflected in a progressive depletion of fibers in the posterior columns.
  25. 25. EXAMINATION RULES OF EXAMINATION  Before beginning a sensory examination , the patient should be explained the exact nature of test and carefully instructed as to what he is supposed to do.  Care should be taken not to tire the patient out or prejudice his mind by suggestions.  In order to ensure accuracy , the patient’s eyes must be kept close or covered.  Patient is instructed to make his response prompt ,as soon as the artificial stimulus is percieved,by uttering the word “yes”to indicate his ability to feel the stimulus.  Otherwise ,the phenomenon of delayed response,which indicates a delay of conduction,may be completely overlooked.
  26. 26. EXAMINATION • RULES OF EXAMINATION  The time elapsing between the stimulus and response , under normal circumstances ,is one-tenth of a second.  In disease states , it may be as long as 10 seconds.  Patient under no circumstance must be asked “did you feel that ” , when a stimulus is applied.  In stuporous or semi conscious patients , response to painful stimuli in the form of wincing , facial grimacing or limb withdrawl , may be the only means available of assessing sensory function.
  27. 27. EXTROCEPTIVE SENSATIONS TOUCH OR TACTILE SENSATIONS  Tested with a wisp of cotton or a fine , soft paint brush touched lightly to the skin , or a mere touch of a finger tip , the patient being instructed to say “ yes “ on immediately feeling the touch.  Touch sensation is recorded as anaesthesia when absent , hypoasthesia when reduced and hyperesthesia when excessive.  Defining an area of hypoesthesia is better achieved by starting within the the area of hypoaesthesia and moving the stimulus out into areas where sensation is normally perceived.  In hysterical anaesthesia , in addition to a non anatomical distribution of the sensory loss , it is common to find a change in the location of anaesthesia with successive tests.
  28. 28. EXTROCEPTIVE SENSATIONS PAIN  A sharp pin with a rounded head is generally sufficient to produce uniform and graduated stimuli.  The following are note worthy: 1 .The shaft of the pin should be long enough to allow the examiner’s index finger and thumb to slide downwards on impact. 2 .A short pin held with index finger on the head of the pin usually produces an indelicate and variable stimulus. 3 .A gentle , but firm and uniform touch is required. 4. Hollow needles should never be used . Puncturing the skin is heavy handed and does not produce an accurate response in an alarmed patient . Also poses the risk of transmitting disease.
  29. 29. EXTROCEPTIVE SENSATIONS PAIN • The patient should be asked to judge whether the stimulus feels as sharp on one side as on the other. • Always suggest the stimuli should be the same, as by language such as, “Does this feel about the same as that?” • Avoid such language as “Does this feel any different?” or “Which feels sharper?” Suggesting there should be a difference encourages some patients to over analyze and predisposes them to spurious findings and a tedious, often unreliable examination.
  30. 30. EXTROCEPTIVE SENSATIONS PAIN. • A commonly used technique is asking the patient to compare one side to the other in monetary or percentage terms. • For example, “If this (stimulating the apparently normal side) side is a rupee’s worth (or 100%), how much is this (stimulating the apparently abnormal side) worth?”. • The latent time in the response to stimulation is eliminated and the delineation more accurate if the examination proceeds from areas of lesser sensitivity to those of greater sensitivity rather than the reverse.
  31. 31. EXTROCEPTIVE SENSATIONS • PAIN • If there is hypalgesia, move from areas of decreased sensation to those of normal sensation. • If there is hyperalgesia, proceed from the normal to the hyperalgesic area. • There may be a definite line of demarcation between the areas of normal and abnormal sensation, a gradual change, or at times a zone of hyperesthesia between them. • If testing is done too rapidly, the area of sensory change may be misjudged. • Applying the stimuli too close together may produce spatial summation; stimulating too rapidly may produce temporal summation. Either of these may lead to spurious findings.
  32. 32. EXTROCEPTIVE SENSATIONS TEMPERATURE • Temperature sensation may be tested with test tubes containing warm and cool water, or by using various objects with different thermal conductivity. • Ideally, for testing cold, the stimuli should be 5°C to 10°C (41°F to 50°F), and for warmth, 40°C to 45°C (104°F to 113°F). • The extremes of free flowing tap water are usually about 10°C and 40°C. • Temperatures much lower or higher than these elicit pain rather than temperature sensations. • The tubes must be dry, as dampness may be interpreted as cold .
  33. 33. EXTROCEPTIVE SENSATIONS TEMPERATURE • Testing temperature may be useful when the patient does not tolerate pinprick stimuli, has confusing or inconsistent responses to pain testing, or to help map an area of sensory loss. • Temperature testing may not be very reliable in patients with circulatory insufficiency or vasoconstriction causing acral coolness.
  34. 34. PROPIOCEPTIVE SENSATIONS SENSES OF MOTION AND POSITION • Sense of motion, also known as the kinetic or kinesthetic sense, or the sensation of active or passive movement. Consists of an awareness of motion of various parts of the body. • The sense of position, or posture, is awareness of the position of the body or its parts in space. • These sensations depend on impulses arising as a result of motion of the joint and of lengthening and shortening of the muscles.
  35. 35. PROPIOCEPTIVE SENSATIONS • Motion and position sense are usually tested together  by passively moving a part and noting the patient’s appreciation of the movement.  recognition of the direction, force, and range of movement.  the minimum angle of movement the patient can detect.  the ability to judge the position of the part in space.
  36. 36. PROPIOCEPTIVE SENSATIONS SENSES OF MOTION AND POSITION Testing joint position sense Pseudoathetosis Romberg’s test TESTING JOINT POSITION SENSE • Patient is asked to say “yes” ,each time he feels movement at a particular joint , when slow and passive movements are being carried out by the examiner. • He is then asked in which direction the movement had taken place. • Each joint of the hands and feet is examined individually
  37. 37. PROPIOCEPTIVE SENSATIONS TESTING JOINT POSITION SENSE • The big toe or index finger is usually selected for testing. • The examiner should hold the sides of distal phalanx with the right hand ,while the left hand is used to steady the interphalangeal joint. • The phalanx is moved up or down taking care to avoid a push-pull stimulus. • Patient must understand what is exactly meant by “up” or “down” movement of the toe • He is asked to shut his eyes during the test and state the direction of toe in relation to neutral position. • To begin with, the test movements have to be somewhat large,once the idea of the test becomes clear to the patient , the smallest possible movements that are detectable should be employed,avoiding sudden or quick jerks at all times
  38. 38. PROPIOCEPTIVE SENSATIONS PSEUDOATHETOSIS • Patients with impaired joint position sense in their fingers may exhibit so called pseudoathetosis • Outstretched fingers drift up or down or to the side when the patient has his eyes closed. • This is because , proprioception having failed, vision is the only means by which the patient knows where his fingers are and can keep them in one place
  39. 39. PROPIOCEPTIVE SENSATIONS ROMBERG’S TEST • Ask the patient to stand with his feet side by side. • Having established that his balance is satisfactory with his eyes open, ask him to close his eyes, having reassured him that nothing untoward will happen. • If he loses balance with his eyes closed, the test is positive. • You need to be prepared to catch the patient if he shows signs of toppling.
  40. 40. PROPIOCEPTIVE SENSATIONS VIBRATION SENSE • A low frequency tuning fork of 128 Hz is used to test the vibration sense. • It must be first demonstrated to the patient by pressing the base of the tuning fork on the sternum, both during and after the cessation of vibration. • Patient is asked to say “ buzzing” or “yes” when he feels the vibration and “no” when he feels only pressure. • When this is made clear to the patient he is asked to close his eyes and vibration sense tested.
  41. 41. PROPIOCEPTIVE SENSATIONS VIBRATION SENSE • Sensation may be tested on the great toes, the malleoli, the tibial tuberosities, anterior superior iliac spines, sacrum , spinous processes of the vertebrae, sternum, clavicle, styloid processes of the radius and ulna and the finger joints. • Testing should compare side to side and distal to proximal sensation. • If vibration is absent distally, the stimulus is moved proximally to the metatarsophalangeal joints, then the ankle, then the knee, then the iliac spines, and so forth.
  42. 42. PROPIOCEPTIVE SENSATIONS PRESSURE SENSATION • Pressure or touch-pressure sensation is closely related to tactile sense, but involves the perception of pressure from the subcutaneous structures rather than light touch from the skin. • It is also closely related to position sense and is mediated via the posterior columns. • Pressure sense is tested by a firm touch on the skin or by pressure on deep structures (muscle masses, tendons, nerves), using finger pressure or a blunt object. • The patient should both detect and localize the pressure. • Strong pressure over muscles, tendons, and nerves tests deep pain sensibility.
  43. 43. CORTICAL OR COMBINED SENSATIONS • Cortical sensations are those that involve the primary sensory areas of the cortex to perceive the stimulus and the sensory association areas to interpret the meaning of the stimulus and place it in context. • The term combined sensation describes perception that involves integration of information from more than one of the primary modalities for the recognition of the stimulus.
  44. 44. CORTICAL OR COMBINED SENSATIONS STEREOGNOSIS • Stereognosis is the perception, understanding, recognition, and identification of the form and nature of objects by touch. • Inability to do this is astereognosis. • Astereognosis can be diagnosed only if cutaneous and proprioceptive sensations are intact; if these are significantly impaired, the primary impulses cannot reach consciousness for interpretation. • Patient is asked to close his eyes,familiar objects such as coins,keys are placed in each hand,and he is asked to name each. • If he is unable to name them, he may be asked to describe each in terms of size,shape and texture.
  45. 45. CORTICAL OR COMBINED SENSATIONS • STEREOGNOSIS • Bunch of keys should not be used since the sound of rattling may betray its nature to the patient. • The test should be carried out simultaneously with both hands , using identical objects. • Astereognosis is usually accompanied by agraphesthesia and other cortical deficits; it may occur in isolation as the earliest sign of parietal lobe dysfunction
  46. 46. CORTICAL OR COMBINED SENSATIONS TWO POINT DISCRIMINATION • This is tested by simultaneously touching areas of skin with two points of an ordinary compass or hairpin or the heads of two ordinary pins. • The patient’s eyes being closed , the points are placed on the skin , sufficiently wide apart to be recognised instantaneously as two points (double contact) and then gradually brought together , until the patient reports being touched with a single point only. • The minimum distance between two points that is appreciated as a double contact by the patient is noted. This distance varies considerably in different parts of the body.
  47. 47. CORTICAL OR COMBINED SENSATIONS TWO POINT DISCRIMINATION • Normal two-point discrimination is about 1 mm on the tip of the tongue, 2 to 3 mm on the lips, 2 to 4 mm on the fingertips, 4 to 6 mm on the dorsum of the fingers, 8 to 12 mm on the palm, 20 to 30 mm on the back of the hand, and 30 to 40 mm on the dorsum of the foot. • Greater separation is necessary for differentiation on the forearm, upper arm, torso, thigh, and leg. • The findings on the two sides of the body must always be compared..
  48. 48. CORTICAL OR COMBINED SENSATIONS GRAPHAESTHESIA • It is the ability to recognize letters or numbers written on the skin with a pencil, dull pin, or similar object. • Testing is often done over the finger pads, palms, or dorsum of the feet. • Letters or numbers about 1 cm in height are written on the finger pads, larger elsewhere. • Easily identifiable, dissimilar numbers should be used (e.g., 3 and 4 rather than 3 and 8). • Loss of this sensory ability is known as agraphesthesia or graphanesthesia.
  49. 49. CORTICAL OR COMBINED SENSATIONS BAROGNOSIS • It is tested by using two coins of different weights but of equal or nearly equal size. • They are placed alternatively and synchronously on the extremity or the part to be tested , the patient being asked to indicate which is heavier. • The capacity to detect weight differences is less on the affected side. • When objects of equal weight are placed in both hands , the one in the affected hand always feel lighter in weight.
  50. 50. CORTICAL OR COMBINED SENSATIONS TOPOGNOSIS • Localisation of touch • Consists of ability to localise stimuli applied to parts of the body with the eyes shut. SENSORY INATTENTION • Sensory extinction, inattention, or neglect is loss of the ability to perceive two simultaneous sensory stimuli. • Testing for tactile extinction uses double simultaneous stimuli at homologous sites on the two sides of the body. • Light touch is most often used. Extinction occurs when one of the stimuli is not felt. • If using pinprick (with equally sharp pins), the stimulus on the abnormal side may feel blunt compared to the normal side.
  51. 51. SENSORY LOCALISATION • Diminution or loss of sensation may occur because of lesions involving the  Peripheral nerves  Nerve roots  Spinal cord  Brainstem  Higher centers of the brain. • Localization depends on the pattern and distribution of the sensory abnormality.
  52. 52. • The primary modalities may be impaired because of disease involving peripheral nerve, spinal root, or sensory pathways within the central nervous system. • When the primary modalities are normal in a particular body region, but the cortical modalities are impaired, a parietal lobe lesion may be responsible. • When some primary modalities are involved more than others, the sensory loss is said to be “dissociated.”. SENSORY LOCALISATION
  53. 53. SENSORY LOCALISATION • The pathways conveying pain and temperature (the spinothalamic tracts) run in a different location than the pathways conveying touch, pressure, position, and vibration (the posterior columns, dorsolateral funiculus, and medial lemniscus). • After running divergently through much of their central course, the pathways converge again as they approach the thalamus and remain together in the thalamocortical projections.
  54. 54. SENSORY LOCALISATION • When the pathways are close together, such as in the peripheral nerve, spinal root, or thalamus, disease processes tend to affect all primary modalities to an approximately equal degree. • When the pathways are remote from each other, such as in the spinal cord and brainstem, a disease process may affect one type of sensation and not another, producing dissociated sensory loss.
  55. 55. SENSORY LOCALISATION • A common example of dissociated sensory loss is lateral medullary stroke, or Wallenberg’s syndrome. • There is a very characteristic pattern of sensory loss , which only involves pain and temperature and completely spares light touch. • The pain and temperature loss involves the ipsilateral face, because of involvement of the spinal tract of cranial nerve V, and the contralateral body, because of damage to the lateral spinothalamic tract, sparing the light touch pathways that are running in the midline in the medial lemniscus.
  56. 56. SENSORY LOCALISATION NERVE AND ROOT • Root (“radicular”) lesions frequently are accompanied by deep, aching pain along the course of the related nerve trunk. • With a lesion affecting a single root, sensory deficits may be minimal or absent because adjacent root territories overlap extensively. • With polyneuropathies, sensory deficits are generally graded, distal , and symmetric in distribution . • Dysesthesias, followed by numbness, begin in the toes and ascend symmetrically. When dysesthesias reach the knees, they usually also have appeared in the fingertips. • The process is nerve length–dependent, and the deficit is often described as “stocking-glove” in type.
  57. 57. NERVE AND ROOT LESIONS DISTAL,SYMMETRIC SENSORY LOSS DUE TO PERIPHERAL NEUROPATHY DERMATOMAL SENSORY LOSS DUE TO CERVICAL RADICULOPATHY DERMATOMAL SENSORY LOSS DUE TO LUMBOSACRAL RADICULOPATHY
  58. 58. SENSORY LOCALISATION SPINAL CORD • If the spinal cord is transected, all sensation is lost below the level of transection. MID THORACIC LEVEL
  59. 59. SENSORY LOCALISATION SPINAL CORD • Lateral hemisection of the spinal cord produces the Brown- Sequard syndrome, with absent pain and temperature sensation contralaterally and loss of proprioceptive sensation and power ipsilaterally below the lesion BROWN SEQUARD SYNDROME
  60. 60. SENSORY LOCALISATION SPINAL CORD • A dissociated sensory loss can reflect spinothalamic tract involvement in the spinal cord. • Bilateral spinothalamic tract involvement occurs with lesions affecting the center of the spinal cord, such as in syringomyelia. • There is a dissociated sensory loss with impairment of pinprick and temperature appreciation but relative preservation of light touch, position sense, and vibration appreciation
  61. 61. SUSPENDED, DISSOCIATED SENSORY LOSS TO PAIN AND TEMPERATURE DUE TO SYRINGOMYELIA
  62. 62. SENSORY LOCALISATION SPINAL CORD • Anterior spinal artery infarction causes dissociated sensory loss. • The anterior spinal artery infarction involves the anterior two-thirds of the cord, sparing the posterior columns, which are perfused by the posterior spinal arteries. • The patients have dense motor deficits and dense sensory loss to pain and temperature but normal touch, pressure, position, and vibration. ANTERIOR SPINAL ARTERY SYNDROME
  63. 63. SENSORY LOCALISATION SPINAL CORD • Dysfunction of the posterior columns in the spinal cord or of the posterior root entry zone may lead to a band like sensation around the trunk or a feeling of tight pressure in one or more limbs. • Flexion of the neck sometimes leads to an electric shock–like sensation that radiates down the back and into the legs (Lhermitte’s sign) in patients with a cervical lesion affecting the posterior columns, such as from multiple sclerosis, cervical spondylosis, or recent irradiation to the cervical region. POSTERIOR COLUMN SYNDROME
  64. 64. SENSORY LOCALISATION BRAINSTEM • Crossed patterns of sensory disturbance, in which one side of the face and the opposite side of the body are affected, localize to the lateral medulla (lateral medullary or wallenberg’s syndrome) LATERAL MEDULLARY SYNDROME
  65. 65. SENSORY LOCALISATION THALAMUS • Hemi sensory disturbance with tingling numbness from head to foot is often thalamic in origin but also can arise from the anterior parietal region. • If abrupt in onset, the lesion is likely to be due to a small stroke (lacunar infarction), particularly if localized to the thalamus. • Occasionally, with lesions affecting the VPL nucleus or adjacent white matter, a syndrome of thalamic pain, also called Dejerine –Roussy syndrome, may ensue
  66. 66. HEMISENSORY LOSS
  67. 67. SENSORY LOCALISATION CORTEX • With lesions of the parietal lobe involving either the cortex or the subjacent white matter, the most prominent symptoms are contralateral hemi neglect, hemi-inattention, and a tendency not to use the affected hand and arm. • On cortical sensory testing, abnormalities are often found but primary sensation is usually intact. • Anterior parietal infarction may present as a pseudothalamic syndrome with contralateral loss of primary sensation from head to toe.
  68. 68. REFERENCES • Hutchisons clinical methods 23rd edition • Golwalla textbook of symptoms and physical signs 14th edition • Bickerstaff’s neurological examination in clinical practice 7th edition • Macleod’s clinical examination 13th edition • Dejong’s neurologic examination 7th edition • Harrison’s principles of internal medicine 19th edition • Bradley’s neurology in clinical practice 7th edition • Adams and victor’s principles of neurology 10th edition
  69. 69. THANK YOU ALL

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