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:
- 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.
- 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.
- 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.