This is the extent of injury that a person must sustain before that person can sue for non-economic damages as a result of a driver’s negligence. “Serious impairment of body function” means an objectively manifested impairment of an important body function that affects the person’s general ability to lead his or her normal life. The issue of whether the injured party has sustained a serious impairment to body function is generally a question for the judge, unless there is some material dispute over the extent of the person’s injury.