 Cognitive assessment Cognitive performance was assessed with 7 tests yielding 11 test scores and covering 7 domains Global, attention, learningmemory, executive function, visuo-spatialvisuo-construction ability, psychomotor speed, languageverbal: the Mini-Mental State Examination MMSE, the California Verbal Learning Test CVLT immediate List A and Delayed Free Recall DFR, Digit Span Forward and Backwards tests DS-F and DS-B, the Benton Visual Retention Test BVRT, Animal Fluency test AF, Brief Test of Attention BTA, Trails A and B and the Clock Drawing Test CDT Supplemental method 1. All participants were judged capable of informed consent and were probed for their understanding of the protocol. Although no formal dementia diagnosis was conducted, all participants were given mental status tests, which they completed successfully. In every case, low mental status performance was due to low literacy level without any sign of dementia. 