During one of my early visits with the neurologist, he conducted a test of which I didn’t understand the significance. He’d already asked me to squeeze his fingers in my fists - “oh come on, squeeze harder” - and now he is ‘thumping’ my fingers.
“What is the neurologist looking for when he is tapping my finger?”
The neurologist is looking to see if there is a finger flexor response. The finger flexor response is demonstrated by a sudden flexing of the thumb and/or index finger. There are two ways to cause this response:
* The doctor snaps or flicks the nail of the middle or 4th finger. A positive finger flexor response elicited in this manner is known as the Hoffmann reflex or sign.
* The doctor holds the middle finger while partially flexing it between his/her finger and thumb, then taps or flicks the underside of that finger. A positive finger flexor response elicited in this manner is known as the Trömner sign.
To view two videos of a positive Hoffmann sign, visit the website of the University of Washington Neurological Surgery Spine Center.
“What causes the thumb to flex?”
The finger flexor response (Hoffmann relex or Trömner sign) is somewhat similar to the Babinski sign in that it is suggestive of a lesion or impingement along the corticospinal track.
Read this post in its entirety:
MS Signs vs. Symptoms: What is the Hoffmann Reflex?