Agraphia

Agraphia or impairment in producing written language can occur in many ways and many forms because writing involves many cognitive processes (language processing, spelling, visual perception, visuospatial orientation for graphic symbols, motor planning, and motor control of handwriting). Central Central agraphia occurs when there are both impairments in spoken language and impairments to the various motor and visualization skills involved in writing. All four of these symptoms result from pathway lesions. Gerstmann's syndrome may additionally be present with alexia and mild aphasia. Though written letters are often so poorly formed that they are almost illegible, the ability to spell aloud is often retained. The orientation and correct sequencing of the writing will also be impaired. ==Causes==

Agraphia has a multitude of causes ranging from strokes, lesions, traumatic brain injury, and dementia. Twelve regions of the brain are associated with handwriting. The four distinct functional areas are the left superior frontal area composed of the middle frontal gyrus and the superior frontal sulcus, the left superior parietal area composed of the inferior parietal lobule, the superior parietal lobule and the intraparietal sulcus and lastly the primary motor cortex and the somatosensory cortex. The eight other areas are considered associative areas and are the right anterior cerebellum, the left posterior nucleus of the thalamus, the left inferior frontal gyrus, the right posterior cerebellum, the right superior frontal cortex, the right inferior parietal lobule, the left fusiform gyrus and the left putamen. specifically the language areas around the sylvian fissure, such as Broca's area, Wernicke's area, and the supramarginal gyrus. Alzheimer's disease Agraphia is often seen in association with Alzheimer's disease (AD). Writing disorders can be an early manifestation of AD. In individuals with AD, the first sign pertaining to writing skills is the selective syntactic simplification of their writing. Individuals will write with less description, detail and complexity, and other markers, such as grammatical errors, may emerge. Different agraphias may develop as AD progresses. In the beginning stages of AD, individuals show signs of allographic agraphia and apraxic agraphia. Allographic agraphia is represented in AD individuals by the mixing of lower and upper case letters in words; apraxic agraphia is represented in AD patients through poorly constructed or illegible letters and omission or over repetition of letter strokes. As their AD progresses, so does the severity of their agraphia; they may begin to form spatial agraphia, which is the inability to write in a straight horizontal line, and there are often unnecessary gaps between letters and words. Normal spellers have access to a lexical spelling system that uses a whole-word; when functioning properly, it allows for recall of the spelling of a complete word, not as individual letters or sounds. This system further uses an internal memory store where the spellings of hundreds of words are kept. This is called the graphemic output lexicon and is aptly named in relation to the graphemic buffer, which is the short term memory loop for many of the functions involved in handwriting. When the spelling system cannot be used, such as with unfamiliar words, non-words or words that we do not recognize the spelling for, some people are able to use the phonological process called the sub-lexical spelling system. This system is used to sound out a word and spell it. In AD individuals, memory stores that are used for everyday handwriting are lost as the disease progresses. ==Management==

Agraphia cannot be directly treated, but individuals can be rehabilitated to regain some of their previous writing abilities. CART is more likely to be successful in treating lexical agraphia when a few words are trained to mastery than when a large group of unrelated words is trained. Words chosen can be individualized to the patient, which makes treatment more personalized. • Graphemic buffer uses the training of specific words to improve spelling. Cueing hierarchies and copy and recall method of specific words are used, to work the words into the short-term memory loop, or graphemic buffer. The segmentation of longer words into shorter syllables helps bring words into short-term memory. • Problem solving approach is used as a self-correcting method for phonological errors. The individual sounds out the word and attempts to spell it, typically using an electronic dictionary-type device that indicates correct spelling. This method takes advantage of the preserved sound-to-letter correspondences when they are intact. This approach may improve access to spelling memory, strengthen orthographic representations, or both. ==History==

In 1553 Thomas Wilson's book Arte of Rhetorique held the earliest known description of what would now be called acquired agraphia. In the second half of the nineteenth century, the loss of the ability to produce written language received clinical attention, when ideas about localization in the brain influenced studies about dissociation between written and spoken language as well as reading and writing. Paul Broca's work on aphasia during this time inspired researchers across Europe and North America to begin conducting studies on the correlation between lesions and loss of function in various cortical areas. During the 1850s, clinicians such as Armand Trousseau and John Hughlings Jackson held the prevailing view that the same linguistic deficiency occurred in writing as well as speech and reading impairments. In 1856, Louis-Victor Marcé argued that written and spoken language were independent of each other; he discovered that in many patients with languages disorders, both speech and writing was impaired. The recovery of written and spoken language was not always parallel suggesting that these two modes of expression were independent. He believed the ability to write not only involved motor control, but also the memory of the signs and their meaning. According to Pitres, Marcé and Ogle were the first to emphasize the dissociation between speech and writing. His work was also strongly influenced by Théodule-Armand Ribot's modular approach to memory. Pitres's clinical case study in 1884 argues for the localization of writing in the brain. Pitres's reading and writing models consisted of three main components: visual (the memory for letters and how letters are put together to form syllables and word), auditory (the memory for the sounds of each letter), and motor (motor-graphic memory of the letters). He proposed the following classifications of agraphia: • Agraphia by word blindness: inability to copy a model, but the individual can write spontaneously and in response to dictation. • Agraphia by word deafness: inability to write to dictation, but the individual can copy a model and write spontaneously. • Motor agraphia: no ability to write, but the individual can spell. Pitres said in aphasia, the intellect is not systematically impaired. Research in the twentieth century focused primarily on aphasiology in patients with lesions from cerebrovascular accidents. From these studies, researches gained significant insight into the complex cognitive process of producing written language. == See also ==