Dysgraphia in Japanese patients with primary progressive aphasia

Dysgraphia in Japanese patients with primary progressive aphasia (PPA) remains underexplored. Japanese writing system-kanji (morphograms) and kana (phonograms)-offers a unique opportunity to study dysgraphia in PPA. We investigated 32 Japanese speakers with PPA: 14 with nonfluent/agrammatic (nfvPPA), 13 with semantic (svPPA), and 5 with logopenic (lvPPA) variants. Writing abilities were assessed through the dictation of 30 kanji and 30 kana words. Patients with nfvPPA exhibited significant kana dysgraphia, reflecting phonological route dysfunction. Kanji dysgraphia predominated in svPPA and lvPPA, with phonologically plausible errors most common in svPPA, indicating orthographic-semantic route impairment. Character stroke errors in kana were more frequent in nfvPPA, possibly reflecting graphemic motor deficits. These findings highlight distinct dysgraphia patterns across PPA subtypes, corresponding to the specific brain regions predominantly impaired in each variant.