Posts Tagged ‘Cerebellar signs’

Intention Tremor

Wednesday, August 20th, 2014

Intention tremor can be elicited by the finger-nose test. In normal patients, the movements between the physician’s finger and patient’s nose should be smooth, but adjustment is allowed according to the patient’s upper limb power. This man has intention tremor and impaired finger-nose test on the right side, whilst the left side is normal.

Discussion on intention tremor

This sign indicates a lesion at the ipsilateral cerebellum. It has been postulated that this sign is due to a loss of movement stabilisation by the cerebellum.

Common causes resulting in cerebellar signs include: stroke, tumour, demyelinating diseases, alcohol or anticonvulsant toxicity.

There are a few points to note for the test:

  1. Clear instructions should be provided to the patient. The physician may help the patient by initiating the first few movements before asking the patient to repeat the movements by himself.
  2. The physician’s finger should not be too close to the patient, otherwise intention tremor cannot be demonstrated, which is often more pronounced at the latter part of the movement. Ideally, there should be an arm’s length between the patient’s nose and the examiner’s finger, so that the patient can fully extend his arm.
  3. The physician may move his finger, within the reach of the patient, when the patient directs his finger to his nose, so as to minimise the effect of practice.

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Heel-shin Test

Wednesday, August 20th, 2014

In this video, the patient exhibits a positive heel-shin test on the right side. Compared to the left (normal) side, the right lower limb is seen to be rather clumsy.

The heel-shin test is a test to screen for ipsilateral cerebellar function. Once again, clear instructions are required for this test, and you could see that for the first couple of times, the examiner is holding the patient’s lower limb and teaching him how to do the test before asking him to do it himself.

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Ataxic Wide-based Gait

Wednesday, August 20th, 2014

The gait is wide-based and the patient requires assistance from the physician for stabilization. The patient cannot turn within one or two steps but requires multiple steps. The physician then asks the patient to perform tandem-walking at the end of the video but the patient is unable to do so due to severe instability. The patient exhibits ataxia which could be due to a cerebellar problem or deficits in proprioception.

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Horizontal Nystagmus

Wednesday, August 20th, 2014

In the first video, the patient has both horizontal nystagmus and vertical “down-beat” nystagmus.

In the second video, the patient has a torsional nystagmus when looking to her right hand side.

Discussion of the sign

Nystagmus is defined as a rhythmic oscillation of the eyes. It usually consists of a slow drifting phase in one direction and a jerky corrective fast phase in the opposite direction. It is often classified into horizontal, vertical or torsional nystagmus. The direction of nystagmus is named according to the fast phase of eye movement by convention. In the first patient, the fast phase of the nystagmus is downward, and hence is termed vertical “down-beat nystagmus” (as opposed to “up-beat vertical nystagmus”). In the second patient, a rotatory component of the nystagmus is seen, and hence the nystagmus is termed “torsional nystagmus”. This is due to the influence of the three different semicircular canals, its pathology of which results in nystagmus in more than one direction, and thus the summation would cause a rotatory component to the nystagmus.

Nystagmus can be a physiological phenomenon. However, in the presence of other vestibular or central nervous system symptoms and signs, pathological causes should be considered. Often pathological causes of nystagmus can be classified into a central or peripheral cause. Central causes include cerebellar or brainstem lesions such as multiple sclerosis, stroke, tumour, spinocerebellar degeneration etc. Drug intoxication such as. due to anti-convulsants, alcohol and sedative hypnotics can also result in nystagmus. Peripheral causes of nystagmus include benign paroxysmal positional vertigo, labyrinthitis and Ménière’s disease.

Whilst the history and physical examination is important in differentiating the cause of nystagmus. Nystagmus which is vertical (e.g. in the first patient) is most likely due a central cause. Whilst nystagmus that is torsional, as in the second patient, is most likely due to a peripheral cause.

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