This included 580 e-scooter riders, more than 7,000 motorcyclists, and more than 7,000 cyclists. More than a third of the injuries recorded among adult e-scooter riders involved traumatic brain injury. Why e-scooters can cause serious injuriesOne explanation for this injury pattern lies in how e-scooters are designed and ridden. Among seriously injured e-scooter riders in the study, only about 6% were recorded as wearing helmets, compared with 45% of cyclists and 76% of motorcyclists. Serious head injuries may need intensive care, brain surgery, or prolonged rehabilitation, while internal bleeding may require emergency surgery.