CoBeN · Novel Network-Based Approaches for Studying Cognitive Dysfunction in Behavioral Neurology

Novel Network-Based Approaches for Studying Cognitive Dysfunction in Behavioral Neurology

To conclude the action, we were able to identify neural networks engaged in language processing of words and non-words in the language with shallow orthography (i.e., Czech). The extent of involvement of the dorsal and ventral language networks was similar to that having been previously described described by our partners in the language with deep orthography (i.e., English). No data has been available in this regard for the Czech language so far. We were also able to describe changes occurring in task-specific (language) and task general (frontoparietal) networks due to physiological aging and in relation to age-related structural brain changes. In patients with Parkinson’s disease, a comparison of English, Czech, and Hungarian acoustic data revealed specific commonalities and differences that underlie hypokinetic dysarthria in these patient groups based on their mother tongue. We were also able to identify structural and functional brain alterations in PD patients as compared to age-matched healthy controls in specific articulatory networks that underlie motor speech problems in PD. The structural volumetric decreases were accompanied by increased functional connectivity between specific regions of interest and demonstrated compensatory mechanisms in PD patients yet without any subjective and objective symptoms of hypokinetic dysarthria. Enhancing excitability of these regions by repetitive transcranial magnetic stimulation (rTMS) led to improved motor speech in PD and was accompanied by increased connectivity of the articulatory networks. This was shown in the prove-of-concept study as well as in a larger randomized controlled parallel-group study. We also examined handwriting and drawing of intersecting pentagons (from the MMSE) using digitized tablets and the results showed that Shannon entropy of the in-air drawing might be a useful marker of early attention and executive function changes prior to the development of mild cognitive impairment in PD (MCI-PD). Whole-brain voxel-based morphometry revealed that the changes were related to volumes of the right superior parietal lobule. Lastly, we focused on top-down and bottom-up control of visual processing in PD (and AD groups) using visual working memory tasks. Both behavioral and fMRI-related brain changes were identified in PD as compared to healthy controls. Early changes in PD were particularly related to altered engagement of the superior parietal lobule, i.e., area involved in both attention and spatial orientation. In AD subjects, it was rather specific frontal regions that showed changes in task-related activations. The results may assist in the early diagnosis of MCI in PD and AD as well as in monitoring disease progression and specific treatment effects.

Data: CORDIS, © European Union