who worked with her specifically on finger recognition tasks, especially on finger calculations. This therapy raised her mathematical ability to a high school level after she received treatment for a number of months. Epidemiology "Gerstmann syndrome and similar posterior parietal symptom combinations (like acalculia) are usually the result of focal cerebrovascular disease in a posterior branch of the left middle cerebral artery or a broader zone infarct, usually involving the angular gyrus or subjacent white matter (Brodmann area 39). In rare cases, traumatic brain injury of an expanding neoplasm in this same region can cause all or elements (acalculia is one of four elements) of the symptoms of this syndrome". History The term "acalculia" was coined by Henschen in 1925; it refers to the decrease in cognitive capacity for calculation that results from damage to the brain. Earlier, in 1908, researchers Lewandowsky and Stadelmann published the first report of an individual with calculation impairment due to brain damage. The individual had trouble performing calculations on paper and mentally. Further, he had difficulty recognizing arithmetic symbols. The report was key in that it established calculation disorders as separate from language disorders, as the two were formerly associated. Henshcen's research was consistent with Lewandowsky's and Stadelmann's finding. From his research, he was also able to propose that certain areas of the brain played particular roles involved in the understanding and execution of calculation. These areas include the third frontal convolution (pronunciation of numbers), the angular gyrus and the fissure interparietalis (reading of numbers), and the angular gyrus again for the writing of numbers. Shortly after Henshen's advances, Berger in 1926 distinguished between primary and secondary acalculia. Primary acalculia is a "pure" condition in which an individual can neither comprehend mathematical concepts nor perform mathematical operations. Secondary acalculia is a loss of calculation abilities that stems from other cognitive difficulties, such as memory. It has been questioned whether primary acalculia can exist independently of other cognitive impairments. In 1936, Lindquist proposed that lesions of different areas of the brain can cause different calculation defects, and that there are therefore several variations of acalculia. In 1940, Gerstmann claimed that acalculia is associated with aspects of Gerstmann's syndrome, which include right-left confusion, agraphia, and digital agnosia. In 1983, Boller and Grafman further concluded that calculation difficulties can also arise from various shortcomings, such as the inability to assign value to the name of a number.