A novel writing to dictation test to investigate lexical and sublexical processes: Italian normative data and preliminary clinical feasibility in Mild Cognitive Impairment and Alzheimer’s disease

Writing abilities can be interpreted within dual-route models, which distinguish lexical and sublexical processes. The present study aimed to validate a novel writing to dictation test to assess both lexical and sub-lexical spelling abilities in an Italian population. A sample of 392 healthy participants provided robust normative data, revealing significant effects of age, education, and sex on spelling performance. Test-retest analyses indicated satisfactory reliability and minimal learning effects. The clinical feasibility of the test was explored in patients with amnestic Mild Cognitive Impairment (MCI) and Alzheimer's disease (AD). MCI patients mainly showed selective difficulties in spelling words with unpredictable orthography, suggesting early lexical impairment, whereas AD patients exhibited more severe and heterogeneous deficits involving both lexical and sublexical processes. Qualitative error analysis revealed multiple dysgraphic patterns, particularly in the AD group. Spelling performance did not significantly correlate with other cognitive domains, which may suggest a relative specificity of writing impairment. While the test provides a useful tool for assessing spelling abilities and characterizing writing to dictation disorders in neurodegenerative conditions, limitations related to sample stratification and socio-demographic representation were noted. The study underscores the importance of including standardized writing to dictation assessments in neuropsychological evaluations.