A general-purpose neuropsychological test battery was selected. Due to the unavailability of current, culturally appropriate, unbiased South African tests (Foxcroft, 2004; van Ommen, 2005), age-appropriate international tests with established utility in cross-cultural and multilingual contexts and in SUD studies were selected. In consultation with an Afrikaans linguistics specialist, appropriate cultural and language adaptations were made to the tests. Examples of these adaptations included replacement of items/terminology unfamiliar to South Africans, simplifications of test instructions, and substitution of items to ensure equivalent difficulty levels in both Afrikaans and English. Test instructions, stimuli, and response booklets were translated into Afrikaans and back-translated into English by independent translators. Hand dominance was established with the Edinburgh Handedness Inventory (EHI) (Oldfield, 1971). Ten composite domain scores were derived from the individual neuropsychological tests as follows: Verbal Story Memory: Immediate and delayed recall of story and thematic units and delayed recognition of Stories E and F from the Children’s Memory Scale (CMS) (Cohen, 1997).Verbal List Learning: Total learning, short-term percent retention, long-term percent retention, learning over trials and trial 5 scores of the Auditory Verbal Learning
