Affiliations: Department of Occupational Therapy and Institute of
Allied Health Sciences, Medical College, National Cheng Kung University,
Tainan, Taiwan | Department of Neurology, Medical College, National
Cheng Kung University, Tainan, Taiwan | Department of Occupational Therapy, I-Shou University,
Kaohsiung, Taiwan
Note: [] Corresponding author: Hui-Ing Ma, Department of Occupational
Therapy and Institute of Allied Health Sciences, College of Medicine, National
Cheng Kung University, 1 University Road, Tainan 701, Taiwan. Tel.: +886 6 235
3535 ext. 5905; Fax: +886 6 237 6604; E-mail: huingma@mail.ncku.edu.tw
Abstract: All published studies on micrographia, a diminution of letter size,
examine handwriting in the horizontal direction. Writing horizontally typically
requires increased wrist extension as handwriting progresses from left to
right. Chinese characters, however, can be written not only horizontally from
left to right, but also vertically from top to bottom. We examined the effect
of handwriting direction on character size and stroke length. Fifteen
participants with Parkinson's disease (PD) and 15 age-matched controls wrote
the same Chinese characters both horizontally and vertically. Handwriting
performance was recorded with a digitizing tablet, and a custom-written
computer program was used to provide objective data about character size and
stroke length. The PD group had a linear decrease in overall character size and
horizontal strokes along the writing sequence in the horizontal direction, but
not in the vertical direction. The controls had shorter horizontal strokes in
the horizontal than the vertical direction, but there was no progressive
shortening of stroke length along the writing sequence. The results suggest
that traditionally reported progressive micrographia in horizontal writing may
not be generalizable to vertical writing. The observed decrease of handwriting
size in the horizontal direction suggests that micrographia in PD may be
associated with wrist extension. For clinical implications, patients may
mitigate their micrographia by changing handwriting direction.
Keywords: Handwriting, micrographia, motor skill, Parkinson's disease
