Upper motor neurone signs are the result of an interruption in the neural pathway above the anterior horn cell.
Characteristic of an upper motor neurone disease are:
- weakness - the extensors are weaker than the flexors in the arms, but the reverse is true in the legs
- muscle wasting is absent or slight - muscle wasting is prominent in a lower motor neurone lesion
- hyper-reflexia and clonus - reflexes are absent or reduced in a lower motor neurone lesion
- no fasciculations - fasciculations occur in a lower motor neurone lesion
- extensor plantar responses