I'm going to assume that the elderly woman either said something to the nursing home worker or spat on her. Meaning the nursing home worker's assault was a reaction to a slight.
When you're caring for elderly patients you really have to be patience with them, and understand that they may say or do things that you may deem questionable.
I wish that the nursing home worker would have been able to show more restraint and refrained from assaulting the elderly patient. Furthermore, it would have been nice if the person filming would have intervened and tried to calm the nursing home worker down.
The nursing home worker could end up being dismissed from her job, in addition, to being arrested for felony assault on an elderly person.