Dysgraphia is a learning disability of written expression, which affects the ability to write, primarily handwriting, but also coherence. It is a specific learning disability (SLD) as well as a transcription disability, meaning that it is a writing disorder associated with impaired handwriting, orthographic coding and finger sequencing (the movement of muscles required to write). It often overlaps with other learning disabilities and neurodevelopmental disorders such as speech impairment, attention deficit hyperactivity disorder (ADHD) or developmental coordination disorder (DCD). In the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), dysgraphia is characterized as a learning disability in the category of written expression, when one's writing skills are below those expected given a person's age measured through intelligence and age-appropriate education. The DSM is unclear in whether writing refers only to the motor skills involved in writing, or if it also includes orthographic skills and spelling. Dysgraphia should be distinguished from agraphia (sometimes called acquired dysgraphia), which is an acquired loss of the ability to write resulting from brain injury, progressive illness, or a stroke. The prevalence of dysgraphia throughout the world is not known, due to difficulties in diagnosis and lack of research. Etymology The word dysgraphia comes from the Greek words dys meaning "impaired" and γραφία graphía meaning "writing by hand". Development There are at least two stages in the act of writing: the linguistic stage and the motor-expressive-praxic stage. The linguistic stage involves the encoding of auditory and visual information into symbols for letters and written words. This is mediated through the angular gyrus, which provides the linguistic rules which guide writing. The motor stage is where the expression of written words or graphemes is articulated. This stage is mediated by Exner's writing area of the frontal lobe. The condition can cause individuals to struggle with feedback and anticipating and exercising control over rhythm and timing throughout the writing process. People with dysgraphia can often write on some level and may experience difficulty with other activities requiring reciprocal movement of their fingers and other fine motor skills, such as; tying shoes, fastening buttons or playing certain musical instruments. However, dysgraphia does not affect all fine motor skills. People with dysgraphia often have unusual difficulty with handwriting and spelling which in turn can cause writing fatigue. Unlike people without transcription disabilities, they tend to fail to preserve the size and shape of the letters they produce if they cannot