A case of isolated dystextia due to subcortical infarction: a novel condition of digital device era.

Background: In recent years, cases of dystextia (texting disabilities) and dystypia (typing disabilities) have been reported. However, reports describing isolated dystextia without aphasia or other cognitive impairments are rare, and the detailed pathophysiology is not fully understood. Most Japanese people use the alphabetical spelling system (Romaji) for texting and typing. Herein, we report the case of a man with isolated dystextia and dystypia resulting from Romaji conversion difficulties.

Case presentation: A 48-year-old, right-handed Japanese man developed texting and typing difficulties. The standard neuropsychological tests showed no signs of aphasia or other cognitive impairments, except for slight executive dysfunction. Thus, isolated dystextia and dystypia were diagnosed. Furthermore, the patient experienced Romaji conversion difficulties. Magnetic resonance imaging revealed a subcortical infarction in the left cerebral hemisphere. Single photon emission tomography revealed hypoperfusion, including in the left dorsolateral frontal cortex.

Conclusions: The left dorsolateral frontal cortex may be related to Romaji conversion in Japanese individuals. Therefore, diaschisis of the left dorsolateral frontal cortex due to subcortical lesions may have impaired Romaji conversion, leading to dystextia and dystypia, in this patient.