Former NFL superstar Chris Johnson just revealed he was diagnosed with ALS last year ... and the disease has progressed so quickly, he now uses a speech-generating device to communicate. The 40-year-old Tennessee Titans great and his wife, Brittany , sat down with Michael Strahan on "Good Morning America" on Monday ... where the All-Pro running back stated he first noticed symptoms with weakness in his right hand. After meeting with medical professionals and undergoing thorough testing, Johnson