ASSESSING COGNITIVE FUNCTIONS IN ARABIC AND ENGLISH SPEAKING POPULATIONS

The aims of this thesis are to assess cognitive functions in adult Arabic populations for clinical purposes, and to examine resulting cultural differences between Arabic and English speaking populations. In the first study, we translated, culturally adapted and validated an existing cognitive screening tool (Cognistat) for its use with Arabic adults with Acquired Brain Injury (ABI), and we examined the differences in cognitive performance between Arabic and English individuals. A total of 107 healthy Arabic speaking adults and 62 ABI patients (30 stroke and 32 traumatic brain injury; TBI) between 18-60 years were involved in the study. The results indicated that the translated/adapted tool is valid and reliable for its use with Arabic individuals with ABI. Cultural differences between Arabic and English individuals were found in orientation to time, memory, language (repetition and naming), construction, calculation and reasoning (similarities and judgment). In the second study we developed and validated a memory test – the Plymouth Saudi Memory Test (PSMT) – that assesses a wide range of memory domains in Arabic adults with ABI; cultural variations in memory functioning between both Arabic and English individuals were also investigated. A total of 80 healthy Arabic speaking adults and 61 ABI patients (30 stroke and 31 TBI) between 18-60 years were tested. The results demonstrated that the PSMT is a valid and reliable test for detecting memory deficits among Arabic adults with ABI, and the comparison between the Arabic and English individuals revealed variations in working memory, semantic memory, and prospective memory. As a follow-up of cultural differences uncovered in the first two studies, the third and final study investigated the effect of length of stay in the UK on unfamiliar faces recognition, as well as cultural differences in unfamiliar faces recognition between Arabic and British individuals. A face recognition task that involved both Arabic and English faces was designed, and 35 participants (19 Arabs and 16 English) between 18-49 were tested. Typically, Westerners show an external feature advantage when processing unfamiliar faces, while participants from Arabic countries show a greater reliance on internal features. Results showed that the expected internal feature advantage in Arabic participants is more likely to be found for those Arabic immigrants who spend more time back in their home country, suggesting that visual processing biases can be modified with exposure in adulthood. Altogether, these results provide the clinical and research community with new tools to evaluate cognitive skills in Arabic-speaking adults, and add to the body of evidence that some of these skills can be shaped by cultural experience. The findings of the cultural differences further our understanding of the potential variations in cognitive functions among people from different cultural backgrounds