Neural basis of writing in prodromal to mild dementia with lewy bodies.

OBJECTIVES: We have previously demonstrated difficulties in written production in dementia with Lewy bodies (DLB) patients. We now aim to determine the neural correlates of writing production in DLB, combining clinical data and structural MRI measures. METHOD: Sixteen prodromal to mild DLB patients were selected to participate in the study. The GREMOTS test was used to assess writing production. Using three-dimensional T1 brain MRI images, correlations between the GREMOTS test and grey matter (GM) volume were performed using voxel-based morphometry (VBM; SPM12, XjView and Matlab R2021b softwares). RESULTS: VBM analysis (p < 0.001, uncorrected) revealed a positive and significant correlation between both left anterior insula and left supramarginal gyrus GM volumes and DLB patients' ability to write logatoms using the phonological route. The handwriting deficit was negatively and significantly correlated to the supplementary motor area. The parkinsonism-like characteristics of agraphia were negatively and significantly correlated with both right anterior and right posterior cerebellum GM volumes. Our study also revealed a negative and significant correlation between grammatical spelling impairments and an area of the orbitofrontal gyrus, and a negative and significant correlation between supramarginal gyrus and general slowness in dictation tasks. CONCLUSION: Writing disorders in early DLB patients appears to be GM decreases in several brain regions, such as the left anterior insula, the left supramaginal gyrus, as well as two areas of the right cerebellum.

[Writing in prodromal and mild dementia with Lewy bodies: an exploratory and preliminary study]. / La production écrite dans la maladie à corps de Lewy prodromale à légère : une étude exploratoire préliminaire.

Dementia with Lewy bodies (DLB) is the second most common form of dementia in elderly patients. In the early stages, it shares many clinical and pathological features with other neurocognitive disorders such as Alzheimer's disease, making early and accurate diagnosis challenging. While written production has been shown to be sensible to pathological aging even before the onset of spoken language disorders, no research has been conducted on this aspect in DLB patients, particularly at the prodromal or mild stages. OBJECTIVE: In order to better characterize their cognitive profiles, our speech therapy study aimed to assess the ability of prodromal or mild DLB patients in writing production. METHODS: Seventeen prodromal to mild DLB patients underwent written tests selected from the French language assessment corpus GREMOTS. The protocol included dictations of words, logatoms, and sentences. These tests were completed with a self-assessment questionnaire about writing disability and an observational table of writing behavior. RESULTS: 18% of patients had a deficit score in dictation of words, 41 % of patients had a deficit score in dictation of logatoms and 35% of patients had a deficit score in dictation of sentences. 71% of patients had a subjective complaint about their handwriting quality. The assessment of handwriting quality also showed difficulties for 76% of patients, with graphic motor pattern disorders and motor symptoms associated with parkinsonism dysgraphia. Finally, our results suggest an impact of working memory, attentional and executive function impairments on logatoms production, and an impact of working memory impairment on long sentences production and grammatical agreements. DISCUSSION: These findings are promising and may improve our knowledge of the prodromal and mild stages of DLB. They may also contribute to improve early diagnosis and clinical practice.