Focussed Exam - Cerebellar and Sensory Ataxia
It makes it easier to remember what to do, and you are less likely to miss anything out. We will start at the top of the body, and work down
Ask the patient to follow your finger, whilst you make an ‘H’ shape roughly about 40cm infront of their eyes.
- Don’t move your finger too quickly – if you do saccades may appear – giving the apparent indication that Nystagmus is present, when it is not.
- Also note that in normal individuals, you get nystagmoid movements at the extremities of gaze – and these are normal.
- Patients with nystagmus often have reduced visual acuity, as they are unable to fixate properly on objects.
- Phasic nystagmus – note the direction of the quick phase
- Pendular nystagmus – appears more like bobbing movements
- Lateral nystagmus – a defect within the cerebellum itself
- Vertical nystagmus – a defect in the brainstem. Sometimes called down beat nystagmus, this is associated with problems with the foramen magnum.
- Internuclearophthalmoplegia (INO) – a defect found specifically in MS.
Ask the patient to say their name and address. If speech appears normal in tis response, ask them to say the phrases:
- British Constitution
- West Register Street
- This may help to elicit any dysarthria
At the same time, you should try to assess the scanning quality of the voice. Patients with cerebellar disorders may put equal emphasis on all words so that normal scanning quality is lost.
- Cerebellar dysfunction – the patient is likely to show past-pointing, and a tremor. The tremor is particularly apparent at nearly-full extension – this is why you should put your finger roughly arm’s length away from the patient.
- Sensory Ataxia – movement may appear slightly slow and un-coordinated. They may be some slight tremor at the extremities of reach
Stretched out arms
- Normal response – arms and fingers will not move. When pressed downwards, arm will return to normal position quickly, and in one smooth movement.
- Cerebellar dysfunction – the arms may pendulum up and down. The fingers may being to move around (piano fingers/Pseudoathetosis). When you press the arm downwards, it may swing past the original point several times before coming to rest (reduced damping of movement)
- Sensory Ataxia – the fingers may gradually move out of position, but are unlikely to move rapidly and freely like in cerebellar dysfunction. Arms and hands may begin to drop – this could be caused by distal weakness, which may or maynot be related to the underlying condition. Unlikely to be pendular movements. When you press the arm downwards there may be slight reduced damping of movement.
Joint position Sense
Coordination – Heel/shin
- Cerebellar disorder – patients are likely to find this difficult, but it is unlikely to be exaggerated by eyes closed
- Sensory Ataxia – patients are likely to find it difficult, but may be able to compensate with visual cues. When eyes are closed, movement disorder will be greatly exaggerated.
- Sensory ataxia – patient is likely to lose balance – this is a positive Rhomberg’s test
- Cerebellar Ataxia – the patient should be no more unsteady than with their eyes open
- Broad based
- May tend to veer to one side – usually the side ipsilateral to any lesion
- High stepping
- Patient looks at their feet as they walk