Patrycja Naumczyk 1, Agnieszka Sabisz 2, Paweł Winklewski 2,3,4, Arkadiusz Szarmach 2, Krzysztof Jodzio 1, Edyta Szurowska 2, Karolina Finc 5, Beata Brzeska 2, Angelika K. Sawicka 6, Karolina Czachowska 3, Robert A. Olek 6
1 Institute of Psychology, University of Gdansk
2 2-nd Department of Radiology, Medical University of Gdansk
3 Department of Human Physiology, Medical University of Gdansk
4 Department of Clinical Anatomy and Physiology, Pomeranian University of Slupsk
5 Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Torun
6 Department of Bioenergetics and Nutrition, Gdansk University of Physical Education and Sport
Regional cerebral grey matter thickness decreases with age, even in elderly considered as successfully aging ones. Yet, the relationship between the brain tissue degradation and cognitive outcome of the older adults is less straightforward. The study aimed at exploring this association further. Forty-six elderly subjects (mean age: 69) took part in the study. Each of the participants underwent thorough neuropsychological assessment and magnetic resonance imaging (MRI) examination. The neuropsychological protocol included fluid and crystalized intelligence estimation, as well as visual memory, and executive functioning evaluation. The cognitive status was confirmed with Mini Mental State Examination score. The MRI scanning sessions were held on two 3T scanners (GE Discovery 750: 27 participants, Philips Achieva TX: 19 participants) with high resolution (1×1x1mm) T1-weighted sequence for anatomical reference. The MRI data was preprocessed in the Freesurfer v.6.0 with standard reconstruction procedures. The cortical thickness was estimated in reference to the Desikan-Killany atlas resulting, in each of the hemispheres, in individual scores for 34 regions, as well as overall mean cortical thickness estimations. Depending on the normality of the distributions of the variables, the Pearson’s or Spearman’s correlation coefficients between the neuropsychological factors, participants’ age, and regional grey matter thickness were computed. If more than one of the variables correlated with the thickness of a given region, a hierarchical stepwise linear regression (for parametric distributions), or a partial Spearman’s correlation (for non-parametric distributions) was performed. Significant associations (p<0,05) were found for 22 metrics of the right, and 23 metrics of the left hemisphere. Surprisingly, participants’ age was a sole predictor of the grey matter thickness only in 9 regions (mostly in the right hemisphere). It was the intelligence (especially fluid one) that was the most prominent estimator of the grey matter thickness preservation (significant linkage in 22 regions, mostly in the left hemisphere). The results provide an additional insight into the complicated relationship between the brain tissue degeneration and cognitive functioning in the elderly.