Dystypia following left lenticulostriate artery cerebral infarction: A case report with MR Tractography and SPECT analysis.

OBJECTIVES

To report a rare case of dystypia-a selective typing impairment-following a subcortical infarction, and to explore its neural correlates using clinical and imaging data.

CASE PRESENTATION: A 65-year-old right-handed man with proficient typing ability developed sudden difficulty typing during a web conference. He showed intact language comprehension, naming, and motor function, but exhibited romanization errors and touch-typing difficulties without agraphia, apraxia, or aphasia, while the Frontal Assessment Battery revealed impaired verbal fluency.

IMAGING FINDINGS: MRI revealed an acute infarct in the left putamen and corona radiata. Diffusion-weighted imaging with tractography showed partial involvement of the fronto-striatal tract connecting the putamen to the supplementary motor area. SPECT demonstrated hypoperfusion in the left frontal and parietal cortices.

CONCLUSION

This case suggests that disruption of the fronto-striatal tract may impair typing ability, even in the absence of classical language deficits. Subcortical lesions can cause highly selective cognitive-motor dysfunctions, and combined clinical and imaging approaches are key to understanding such atypical post-stroke presentations.