From micrographia to Parkinson's disease dysgraphia

Micrographia, an abnormal reduction in writing size, is a specific behavioral deficit associated with Parkinson's disease (PD). In recent years, the availability of graphic tablets has made it possible to study micrographia in unprecedented detail. Consequently, a growing number of studies show that PD patients also exhibit impaired handwriting kinematics. Is micrographia still the most characteristic feature of PD‐related handwriting deficits? To answer this question, we identified studies that investigated handwriting in PD, either with conventional pencil‐and‐paper measures or with graphic tablets, and we reported their findings on key spatiotemporal and kinematic variables. We found that kinematic variables (velocity, fluency) differentiate better between control participants and PD patients, and between off‐ and on‐treatment PD patients, than the traditional measure of static writing size. Although reduced writing size is an important feature of PD handwriting, the deficit is not restricted to micrographia stricto sensu. Therefore, we propose the term PD dysgraphia, which encompasses all deficits characteristic of Parkinsonian handwriting. We conclude that the computerized analysis of handwriting movements is a simple and useful tool that can contribute to both diagnosis and follow‐up of PD. © 2014 International Parkinson and Movement Disorder Society     

A case of micrographia after subcortical infarction: possible involvement of frontal lobe function

Most reports of micrographia associated with focal brain lesions have related this finding to damage in the left basal ganglia. Here we describe the case of a 68-year-old man presenting with reversible micrographia accompanied by hypophonia in the absence of extrapyramidal signs after cerebral infarction in the left subcortical region. At the time of the patient's admission, diffusion-weighted magnetic resonance imaging sequence showed the lesion to principally involve the corona radiata, with some involvement of the putamen. Neurologically, mild right-sided brachiofacial hemiparesis and grasp reflexes - a frontal lobe sign - were observed. As his micrographia and hypophonia improved, the patient's grasp reflexes improved in parallel. In addition, recovery of regional cerebral blood flow in the left frontal lobe was confirmed by single photon emission computed tomography (technetium-99 m HMPAO). The present case suggests the possibility that the function of frontal-subcortical circuit might also be involved in the production and improvement of micrographia and that micrographia and hypophonia may share a common pathophysiology.     

Fast micrographia: An unusual but distinctive sign

Fast micrographia is a rare clinical sign, which is reported in patients with pallidal pathology. A 68-year-old male presented with hypophonia and short shuffling gait with decreased arm swing. About 3 weeks before, he had an acute myocardial infarction and a period of hemodynamic and respiratory distress during which he required mechanical ventilatory support. He was found to have a fast handwriting with micrographia from the outset. His rapid alternating hand and finger movements were normal. Magnetic resonance imaging (MRI) of the brain showed features of hypoxic ischemic encephalopathy including hyperintensities on T1 and T2 weighted images in the globus pallidus, and putamen bilaterally.     

Fast micrographia and pallidal pathology

Fast micrographia differs from the customary micrographia of Parkinson's disease and appears to be characteristic of patients with pallidal lesions. © 2003 Movement Disorder Society     

Withdrawal of visual feedback improves micrographia in Parkinson's disease.

Micrographia is a common, often presenting feature of Parkinson's disease. We assessed a simple writing paradigm in 40 PD patients "off" medications, 40 different PD patients "on" medications, and 64 age- and sex-matched controls. Patients wrote "Today is a nice day" with both eyes open and eyes closed to assess the effects of visual withdrawal (eyes closure). The order (eyes open vs. eyes closed) was alternated. In the "off" medicine group, eye closure increased the writing length by 14.0 +/- 10.1% (P < 0.05) from a mean of 69.1 to 77.7 mm [range -14% to +73%]. The percentage increase was larger in the 20 subjects with the smallest baseline writing size (worse micrographia), compared to the 20 with relatively larger writing (19.5% vs. 7.9%, P < 0.05). Neither the "on" medicine group, nor the control group changed. Simple eye closure significantly increased writing size in "off" PD patients to a similar or greater amount as levodopa. This data suggests that micrographia is not a pure motor hypokinetic feature but is affected by PD similar to other superlearned tasks such as walking. Furthermore, some patients have adapted this simple eye closing strategy when writing, especially signatures.