Hyperreflexia

Hyperreflexia is a classic sign of UMN disease but can be seen in other conditions such as thyrotoxicosis.
Hyperreflexia in one limb or in lower but not upper extremities can help localize lesions.

Patient 4

This is a young man with neurosarcoidosis with right-sided brain lesions corresponding to left-sided hyperreflexia and clonus.