Table 1.

Description of neuropsychological test battery

Letter-digit substitution test [27]	This test provides a measure of psychomotor performance that is relatively unaffected by intellectual prowess and is suitable for groups with an age range exceeding 60 years. The number of items written down in 90 s is registered, as in the decrease in performance when graphomotor speed is involved
Visual verbal learning test [27]	This version of the Rey Auditory Verbal Learning Test calls for various aspects of verbal learning and recall. Measures used for analysis are memory performance on trial 1 as indicator of immediate recall, total recall after five trials, delayed recall and recognition after 20 min as indicators of memory consolidation into long-term memory, and a delta score as a measure of learning capacity
Stroop color-word test [27]	This test is a selective attention task aiming at measuring interference susceptibility and consists of three subtasks with increasing task complexity
Categoric word fluency [28]	A simple task requiring the generation of words from semantic categories (animals) within a limited time
Concept shifting test [29]	This test, which has two conditions of complexity, predominately measures functions associated with executive function, especially visual scanning and conceptual tracking. The motor component of this task is measured by three dummy conditions in which no cognitive capacity except for graphomotor speed is required
Memory comparison test (MCT)	Selective attention, mental concentration, memory and information processing