Named for the Viennese neurologist Josef Gerstmann, who was the first to describe it in the 1920s, it is characterized because patients present four symptoms: alterations in the ability to express ideas by writing ( agrafia ), inability to count and perform operations. simple arithmetic ( acalculia ), inability to recognize the fingers of the hand ( digital agnosia ) and right-left disorientation .
It is usually associated with damage to a specific part of the brain, the angular gyrus of the parietal lobe of the left hemisphere . The patient, who does not distinguish between right and left, mistakes for example the letter "b" with "d" and "p" with "q".
