Jaw clonus was also one of Chris's VERY early symptoms.
Even though it was summer, the minute a breeze would touch him his jaw would chatter violently. This was before his speech was even slurring. He didn't even mention it to me at the time as it would just happen randomly and he would shrug it off as another strange thing that happens but means nothing.
At our first clinic visit when he was diagnosed, the neurologist kept randomly calling all sorts of people into the room and using his little reflex hammer would demonstrate his clonus that he could reproduce with a simple tap ...