Testing of Upper Extremity Cerebellar Function

Ovid: Field Guide to the Neurologic Examination

Authors: Lewis, Steven L.
Title: Field Guide to the Neurologic Examination, 1st Edition
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– Neurologic Examination > Cerebellar Examination > Chapter 34 –
Testing of Upper Extremity Cerebellar Function

Chapter 34
Testing of Upper Extremity Cerebellar Function
The purpose of testing upper extremity cerebellar
function is to look for evidence of a lesion involving the cerebellar
hemispheres or the cerebellar pathways.
The finger-to-nose maneuver, a simple screening test of
upper extremity cerebellar function, should be performed on all
patients as part of a standard neurologic examination. Other tests of
upper extremity cerebellar function, such as rapid alternating
movements or testing for rebound, don’t need to be performed routinely.
These additional tests of cerebellar function should be performed when
the possibility of cerebellar dysfunction is suggested by the history
or you need to look for additional confirmation of cerebellar
dysfunction when an abnormality is suggested on the finger-to-nose test.
The basic relevant neuroanatomy of the cerebellum and its pathways is discussed in Chapter 33,
Approach to the Cerebellar Examination. The left cerebellar hemisphere
coordinates the left arm (and leg), and the right cerebellar hemisphere
coordinates the right arm (and leg). Table 33-1 summarizes the lesions within the cerebellum or its pathways that may cause incoordination on examination.
Finger-to-Nose Examination
  • Ask the patient to “make a pointer” with his or her index finger.
  • Ask the patient to touch his or her nose with that index finger.
  • Hold your index finger directly in front
    of the patient, at nearly an arm’s length away from him or her, and ask
    the patient to touch your index finger.
  • Ask the patient to repeat the process
    back and forth a few times, moving his or her index finger between the
    tip of the patient’s nose and your index finger, as smoothly as
  • Repeat the same process with the patient’s other arm.
Rapid Alternating Movements (Diadochokinesia)
  • Show the patient what you will be asking
    him or her to do by holding one of your hands stationary with its palm
    up, then rapidly clap your other


    on the stationary hand, alternately turning the moving hand palm side
    up or palm side down (i.e., alternating pronation and supination),
    alternating between each clap.

  • Ask the patient to perform this maneuver
    on one side while you watch for a few seconds. If you suspect that the
    patient might be ataxic on a particular side, it is probably best to
    have the patient begin the test by moving the good side and holding the
    other (potentially ataxic) arm stationary.
  • Then ask the patient to perform the same
    maneuver with the opposite hands (i.e., keeping the other hand
    stationary) while you observe for a few seconds.
  • Ask the patient to hold both arms directly in front of him or her, palm side down.
  • Tell the patient to try to keep the arms
    in the same position without moving and specifically to resist your
    attempt to push the arms down.
  • Using both of your hands, press down on
    the dorsum of both of your patient’s hands while the patient resists
    that force, and then let go.
  • Observe the response of the patient’s arms after you let go of them.
Finger-to-Nose Examination
Normally, the patient should be able to perform the
finger-to-nose maneuver smoothly and accurately with each arm, and
there should be no significant asymmetry between the two arms.
Rapid Alternating Movements (Diadochokinesia)
Patients should normally be able to rapidly clap one
hand on the other, alternating supination and pronation of the moving
hand, fairly smoothly and accurately on each side. Some neurologically
normal patients, however, perform this maneuver slightly less smoothly
when the nondominant hand is the moving hand.
Test for Rebound
Normally, the patient’s arms should rebound slightly
upward when you release your downward pressure on them. This slight
rebound should be symmetric, however, and the patient’s arms should
rapidly return to their straight, forward position.
Finger-to-Nose Examination
  • Clumsiness of an arm during the
    finger-to-nose maneuver is abnormal. Clumsiness due to cerebellar
    dysfunction usually manifests as side-to-side wavering of the arm
    (including movements at the shoulder) throughout its attempt to reach
    its target; this is referred to as dysmetria or appendicular ataxia (or simply ataxia). See Chapter 33, Approach to the Cerebellar Examination, for a discussion of the terminology describing cerebellar dysfunction.
  • Assuming the patient’s arm is strong
    (cerebellar hemisphere lesions do not cause weakness), clumsiness
    during the finger-to-nose maneuver on one side suggests cerebellar
    hemisphere dysfunction ipsilateral to the side of the clumsy extremity.
  • P.114

  • When patients with mild weakness in an
    extremity also have what appears to be significant cerebellar dysmetria
    in the same extremity (and the subtle weakness doesn’t seem to be
    severe enough to explain the dysmetria), the lesion may be in the
    contralateral posterior limb of the internal capsule or the pons. This
    is called an ataxic-hemiparesis (see Table 33-1).
Rapid Alternating Movements (Diadochokinesia)
  • Inability to rapidly, smoothly, and
    accurately perform rapid alternating movements in the upper extremities
    is abnormal and is called dysdiadochokinesia.
    As noted in the section Normal Finding, however, a mild asymmetry in
    ability to perform this test (worse in the nondominant hand) may not be
  • In the absence of any weakness, a
    significant problem performing rapid alternating movements on one side
    (dysdiadochokinesia) is suggestive of cerebellar hemisphere dysfunction
    ipsilateral to the side of the clumsy extremity.
  • This test can be particularly affected by
    weakness, so in the presence of any weakness in an extremity,
    difficulty with rapid alternating movements can be a nonspecific
Test for Rebound
Rebound, manifested by a loss of the normal check
mechanism when you release your downward pressure on the patient’s arm,
is abnormal. The abnormal side rebounds significantly upward and then
bounces down and up several times, as if it is held by a loose spring,
before finally settling back to the straight, forward position. The
finding of rebound, like the finding of dysmetria or
dysdiadochokinesia, is ipsilateral to the abnormal cerebellar
  • The patient’s eyes should be open
    throughout the cerebellar examination, including during the
    finger-to-nose maneuver. No additional information regarding cerebellar
    function is learned by having the patient’s eyes closed.
  • During the finger-to-nose maneuver, it is
    usually not necessary to give the patient a variable target by moving
    your finger to different positions, but occasionally this is helpful to
    bring out dysmetria that was not otherwise evident (or to further prove
    that the patient’s coordination is good). To do this, move your finger
    to a different position—always at approximately the same distance from
    the patient (i.e., slightly less than an arm’s length away)—when the
    patient brings his or her finger to his or her nose, and then keep your
    finger stationary in the new position until the patient brings his or
    her finger to yours.
  • The bounciness of an arm on the side of
    cerebellar dysfunction, as seen on the test for rebound, may
    occasionally be suggested earlier in the examination when the patient
    brings the arms into position when testing drift.

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