The chances of having a stroke after neck manipulation are very slim (about one in every one million manipulations). In more than 90 percent of cases, symptoms occur within 48 hours of manipulation. At least half of the time, the start of symptoms is immediate. A delay of more than a week is extremely rare and has only been reported once.
The most common symptom of stroke is loss of coordination. Other symptoms include difficulty swallowing, dizziness, change in vision, and numbness in the face, head, neck, arm, or hand. Any new or unusual symptoms after neck manipulation should be reported to your doctor.