Supplementary Table 4.

Definition of writing errors on single-word level

Errors	Subtypes	Definition
Unintelligible word	Stroke error	Stroke adding, omission, reforming, and moving
	Radical error	Radical substitution, adding, omission, deforming and moving
	Unreadable	A unreadable sample that cannot be classified as stroke error/radical error
Word substitution	Semantic substitution	Substitution of another meaningful word, whose meaning is close to the target word
	Phonological substitution	Another word with similar pronunciation to the target word
	Number substitution	Use of an arabic number as substitute for a Chinese number word
Ideograph		Use of a picture or the part of a picture to substitute
Mirror writing		Writing in the direction that is the reverse of the natural way, such that the result is the mirror image of normal writing
Visuospatial impairment		The improper organization of the direction, relative size, position, and order of the characters