In January 2007, a meta-analysis published in the journal Neurology determined updated rates of the most common neurological disorders . The review found that 183 out of every 100,000 people suffer a stroke each year. Most studies included in the analysis attributed 80% or more of all strokes to ischemia (meaning a localized deficiency of blood caused by a clot obstructing arterial flow). In contrast, the incidence of a hemorrhagic stroke (meaning bleeding in the brain) is much more rare and is associated with higher mortality rates. Indeed, a study of stroke incidence rates and case fatality in 15,792 middle-aged adults found that hemorrhagic strokes were 4.5 times as fatal as ischemic strokes .