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Definition and Symptoms

Micrographia is a symptom of motor disorders in humans characterized by writing that starts normal sized and then becomes increasingly smaller. Micrographia represents part of the constellation of symptoms presented by Parkinson's disease. The reason Parkinson's disease commonly results in micrographia is because Parkinson's disease inflicts one of the most important centers for motor control in the brain: the basal ganglia. The basal ganglia is comprised of several parts, all of which are responsible, among other things, for the fine motor control necessary to perform such tasks.

Here is how micrographia might demonstrate itself in a patient with Parkinson's disease, without the help of visual guidelines:

Hello, I have Parkinson's disease


Thankfully, when it comes to motor control, the human brain is highly redundant. The precentral gyrus (primary motor cortex - M1),  cerebellum, and various other places along the cortex serve as centers and relay stations for motor activity. Therefore, many other parts of the brain are capable of performing the functions necessary to overcome micrographia. Nevertheless, the patient will not be able to write fluidly in the proper horizontal gauge without visual guidelines, or cues. By simply offering two lines in which to write, much like the lined writing paper found in grade schools, the patient can overcome the micrographia:

Hello, I have Parkinson's disease.

This sort of compensation for motor difficulties using visual guidelines is typical of other physical training for people with Parkinson's disease. While walking becomes a difficult, fettered activity for those inflicted, a checkered floor can assist the patient in walking by presenting a visual cues for calculating the length of their gait. This checkered floor training appears in the movie The Awakening, if that strikes a chord.

Physicians often use the severity of micrographia to determine for the level of progression of Parkinson's disease. If a patient's micrographia is more severe than last session's results, Parkinson's disease has overtaken more of the basal ganglia and is therefore in a more advanced state.


http://www.pdf.org/ ~ Parkinson's Disease Foundation

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