Van Gemmert A W, Teulings H L, Stelmach G E
Arizona State University, Tempe, AZ, USA.
Brain Cogn. 2001 Dec;47(3):504-12. doi: 10.1006/brcg.2001.1328.
Parkinson's disease (PD) patients often show reductions in writing size (micrographia) as the length of the text they produce increases. The cause for these reductions in stroke size are not well understood. Reductions in stroke size could be associated with either concurrent processing demands that result from the coordination and control of fingers, wrist, and arm during writing and the processing of future words or increased extension of the wrist joint as the execution of the writing progresses to the right across the page, resulting in increased stiffness in the pen-limb system. Parkinson's patients and elderly controls wrote phrases of different lengths with target patterns in various serial positions. When the number of words to be written increased, PD patients reduced their stroke size of the initial target pattern, while the elderly controls did not reduce their stroke size. There was no systematic change in stroke size of the second pattern as function of serial position. This result suggests that PD patients reduce the size of their handwriting strokes when concurrent processing load increases.
帕金森病（PD）患者在书写文本长度增加时，常常会出现书写字体变小（小写症）的情况。笔画大小减小的原因尚未完全明确。笔画大小的减小可能与书写过程中手指、手腕和手臂协调控制以及对后续单词处理时产生的并发处理需求有关，也可能与随着书写在页面上向右进行，手腕关节伸展增加，导致笔 - 肢体系统僵硬增加有关。帕金森病患者和老年对照组书写不同长度的短语，并在不同的连续位置设置目标模式。当要书写的单词数量增加时，帕金森病患者会减小初始目标模式的笔画大小，而老年对照组则不会减小笔画大小。第二个模式的笔画大小没有随着连续位置的变化而出现系统性改变。这一结果表明，当并发处理负荷增加时，帕金森病患者会减小其书写笔画的大小。
