Normally, when you drag a pointed object along someone foot from heel to big toe, the toe will curl down. However, in ALS, the toe goes in the opposite direction and point upwards. What is this called?
(b) The Babinski sign
(c) The Stransky sign
ANSWER: The Babinski sign.
The Babinski sign is a test of what’s called the plantar reflex – the natural tendency for the toes to curl down when something is scraped across the bottom of the foot. In ALS, there is an abnormal response in that the toes go upwards. Actually, in infants up to the age of one, you can see the Babinski sign but it disappears and is pathological in adults.
The test is named after Joseph Babinski (1857-1932) who was a Polish neurologist. He presented his observation about the plantar reflex at a conference in 1896 in Paris, and it then became referred to as the Babinski sign or Babinski reflex.
About Joseph Babinski on Wikipedia.
About ALS from the ALS Association.