Atrophy of the brain begins to accelerate at around seventy years of age,[5] which leads to a significant reduction in brain mass. Since the skull does not decrease in size with the brain, there is significant space between the two when this occurs which puts the elderly at a higher risk of a subdural hematoma after sustaining a closed head injury.[3] The reduction of brain size can lead to issues with eyesight, cognition and hearing.[5]