Camillo Negro (1861-1927) and the "bulbo-palpebral hyperkinetic phenomenon" in peripheral facial palsy.

Camillo Negro (1861-1927) was a leading Italian neurologist and neuropathologist between the nineteenth and twentieth centuries. He is best known for describing the cogwheel sign in Parkinson disease. In an article published in 1906, Camillo Negro described the "bulbo-palpebral hyperkinetic phenomenon": in peripheral facial paralysis, if the patient is asked to look up, the eyeball deviates outwards and elevates farther on the affected side. Negro thoroughly investigated the neuroanatomic and neurophysiological basis of this phenomenon that gained a certain popularity and was reported in several articles and textbooks. This sign retains some utility in peripheral facial palsy to identify a doubtful or very slight impairment of the upper face muscles, which may otherwise go unnoticed. The interest towards the semiology of peripheral facial palsy was shared by Negro's assistant Giuseppe Roasenda (1879-1959), who in 1933 described the incomplete convergence of the eyeballs in this condition.