In bed, the vibrations and shaking are very different from the commonly experienced heartbeat frequency vibrations in mattresses and springs, and cannot be attributed to that natural effect.
In one case, that of Victor N. Moturi of Fayetteville, North Carolina, these vibration attacks became so frequent and pronounced during Victor's university classes that Victor had to quit his studies. Here below are the letters from one professor and one witness that describe vibrations of such amplitude that they were seen by others, and were in fact very disruptive to Victor's classes. At the time of posting, we in the electronic harassment/organized stalking target community do not have an explanation as to how powerful and surgically localized vibrations can be induced at a distance, as mainstream science has yet to recognize the work of experimenters who have duplicated remote physical manipulation at a distance, such as John Hutchison.