Q. Can an elderly and mute person count Sefira by blinking his eyes to signal how many days it is today?
Can a Paraplegic patient that can move his wheelchair using only his brainwaves, use those same waves to count Sefira by moving an object with his mind several times?
A. On question 785, 788 and 789 regarding twitting sefira, using sign language or counting with one’s fingers, we wrote: “Horav Shlomo Miller’s Shlit”a opinion is that although twitting is indeed similar to writing and if you maintain that writing is like speaking, you would comply with Sefira counting. (See question 785 that Poskim disagree).
However, you cannot use any sign language for Sefira counting, since for the purpose of this particular mitzvah that requires actual counting, it is not considered as verbal counting.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a