n_exam_sensorimotor

sensory & motor testing including reflexes, coordination & balance

Motor examination:

  • to detect the presence of a CNS lesion causing extremity weakness:
    • the simplest, most rapid & subtle test is for “drift”:
      • the sitting patient is asked to close his eyes & hold his arms out horizontally with palms up for 30secs.
        • if weakness is present, the hand & arm on the affected side will slowly drift or pronate.
      • lie pt prone with knees bent 90deg. and legs pointing vertically up for 30secs
        • a weak leg will tend to drift & drop
    • another sensitive test for extremity weakness is hand grasp, & foot plantar and dorsiflexion
      • test hand grasp using both hands with examiner's hands crossed in front of him so that one can test pt's ulnar side which is more reliable than radial aspect.
  • if abnormal results or peripheral nerve or muscle injury, then more formal testing is needed.
documentation of muscle strength
scoreresult of testing
5+Normal
4+Slightly less than full power against strong resistance
4Able to overcome moderate resistance
4-Able to overcome mild resistance
3Able to accomplish full ROM against gravity
2Able to accomplish full ROM with gravity eliminated
1Only trace muscle contraction, may only be palpable
0Flaccid

Sensory examination:

  • as with other aspects of the neuro. exam., if abnormal findings or specific symptoms then more detailed testing is indicated.
  • testing for pain sensation is best done by double simultaneous stimulation (as for trigeminal nerve)
    • to exclude CNS lesions, if testing on dorsum of hands & feet is normal no further testing for pain is needed
  • double simultaneous stimulation with gauze or wisp of cotton wool can be used to test light touch
    • NB. light touch is usually spared in unilateral spinal cord lesions
  • testing for isolated nerve injuries:
    • 2 point discrimination with paper clip ends, normal is 2-8mm on fingertips & up to 75mm on upper arm & thigh
  • proprioception is the most sensitive & easiest test for post. column pathway deficits
    • move great toe up or down & ask pt which way you moved (upper limb not usually needed to be tested)
  • stereognosis is dependent on touch & position sense as well as post. column & sensory cortex function:
    • ask pt to identify a familiar object placed in palm (eg. key or paper clip)
  • vibration sense is often the 1st sensation lost in peripheral neuropathies such as alcoholism or diabetic:
    • place vibrating tuning fork over DIP jt of a finger & the great toe, ask pt to tell you when vibration disappears.
    • if sense is absent, move to a more proximal joint

Reflexes:

  • document as: 0 = absent; 1+ = diminished; 2+ = normal; 3+ = hyperactive; 4+ = hyperactive with clonus;
  • symmetric hyporeflexia may be normal or due to sedation, hypercalcaemia
  • asymmetric reflexes indicate neurologic or muscular dysfunction.
  • to evaluate the L4-5 nerve root (as in disc prolapse) test power of extensor hallucis longus
  • +ve Babinski reflex (up-going plantar reflex) indicates an upper motor neuron lesion
reflexes and their spinal cord levels
Upper ExtremitylevelLower Extremitylevel
PectoralC4-5PatellarL2-4
BicepsC5-6AchillesS1-S2
TricepsC7 (8)HamstringsL5-S1
BrachioradialisC5-6CremastericL1-2
Upper abdomenT6-9BulbocavernosisS3-4
Lower abdomenT10-12Anal winkS3-5

Coordination and balance:

  • cerebellar function:
    • place finger on nose test with each hand & eyes closed (or finger to examiner's finger then to pt's nose, eyes open)
    • heel-to-shin testing with each leg (ankle to knee and back again)
    • rapid alternating movements eg. touch each fingertip with thumb; supinate/pronate hand; tap floor with foot;
  • balance is a function of vision, vestibular sense and proprioception, 2 must be intact to maintain balance:
    • Romberg test - stand with feet together
      • pt with vestibular deficit will report vertigo
      • close eyes if proprioceptive deficit, pt will sway ⇒ +ve Romberg's
    • tandem gait (heel-toe walking) is sensitive but not specific test of balance.
n_exam_sensorimotor.txt · Last modified: 2010/01/08 02:06 (external edit)