Neuropsychology

All participants took part in neuropsychological evaluation. The assessments were conducted by trained neurologists or neuropsychologists. The language of the evaluation was Hungarian. We selected the Hungarian version of ACE (Stachó et al., 2003) to assess cognitive function. It is known for its high specificity and sensitivity in the diagnosis of cognitive disorders (Dudas et al., 2005). It tests six cognitive domains, namely, orientation, attention, memory, verbal fluency, language, and visuospatial abilities with a maximum score of 10, 8, 35, 14, 28, and 5, respectively, resulting in a maximum total score of 100. A total score of 83 as the cut-off score has an 82% sensitivity at age > 65 years (Mathuranath et al., 2000). Calculating the ratio of verbal fluency (V) and language (L) subscores/orientation (O) and delayed recall memory (M) subscores [VLOM ratio: (V + L)/(O + M)] enables differentiation between AD and frontotemporal dementia (FTD). The normal range of the VLOM ratio is between 2.2 and 3.2. A value higher than 3.2 indicates Alzheimer’s-type dementia, while a value lower than 2.2 demonstrates frontotemporal-type dementia. Visuospatial abilities are tested by asking the participant to copy two overlapping pentagons, to copy a cube, and to draw a clock face with the hands set at a specified time. Verbal fluency is analyzed with two tasks to examine categorical fluency (naming of animals) and phonemic fluency (listing words starting with the letter “m”). Furthermore, the Mini-Mental State Examination (MMSE) is incorporated in the ACE, enabling dementia severity assessment. Its total score ranges from 0 to 30, with higher scores indicating better cognitive performance. Patients with AD had MMSE < 25, while controls had >25.

Depression and anxiety may impair cognitive function (Kramer and Reifler, 1992; Seignourel et al., 2008). To reduce the influence of depression and anxiety on the data, we included the Beck Depression Inventory II (BDI-II) and Spielberger State and Trait Anxiety Inventory (STAI) in our test battery. A BDI-II score of less than 13 demonstrates minimal depression. Scores between 14 and 19 indicate mild depression, those between 20 and 28 refer to moderate depression, and a score of 29 or higher demonstrates severe depression. A low level of anxiety is indicated by a score of 45 or less for both state and trait anxiety. Participants with a BDI-II score of >13 or an STAI score of >45 were excluded from our analysis.