Association between biological markers of sickle cell disease and cognitive functioning amongst Cameroonian children.

BACKGROUND: Some of the major complications of sickle cell disease (SCD) occur in the brain and apart from overt stroke, patients also present with cognitive impairments. We sought to evaluate the prevalence of cognitive deficits as well as their biological predicting factors in young SCD patients in Cameroon. METHODS: The cognitive performances of Cameroonian SCD young patients were evaluated using a neuropsychological test battery assessing four domains of cognitive functioning (executive functions, attention, memory, and sensory-motor skills) previously adapted and normalized on healthy subjects in Yaoundé. FINDINGS: Up to 37.5% of the 96 SCD patients aged 6 to 24 years (M = 13.5, SD = 4.9) had mild-to-severe cognitive deficits. The cognitive deficits tend to increase with age. There was a significant effect of SCD on executive functions and attention, whereas SCD patients performed as well as controls on memory and sensory-motor skills tests. Structural equation models showed a significant association between (a) severe anemia and lower executive functioning, (b) low fetal hemoglobin levels and lower executive functioning and attention, (c) history of cerebrovascular accidents and lower performances in executive functioning, sensory-motor skills, and memory, (d) pathological electroencephalogram and lower attention, and (e) abnormal Transcranial Doppler and lower memory. CONCLUSION: SCD patients in Cameroon presented a very high prevalence of cognitive deficits, with a specific impairment of executive functions and attention. Routine neuropsychological evaluation for early detection of cognitive deficits in SCD patients could represent a cost-effective tool to implement in resource-limited contexts such as in sub-Saharan Africa.

Neuropsychology in Cameroon: first normative data for cognitive tests among school-aged children.

INTRODUCTION: Very few normative data on psychometric tests are available in sub-Saharan African countries, in spite of the obvious needs and potential benefits from psychological and neuropsychological examination in these contexts. The goal of the ongoing overall project is to assess the cognitive functioning of Cameroonian school-aged children suffering from Sickle Cell Disease. For this purpose, normative data on psychometric tests adapted to the Cameroonian cultural context had to first be established. METHOD: 125 "healthy" school-aged Cameroonian children were recruited from public schools in the city of Yaounde and were given a battery of 14 cognitive tests assessing executive functions and memory. Criteria for tests inclusions were: simplicity of administration, few verbal demand, and broad cross-cultural applicability. Results allow concluding that the battery is appropriate for neuropsychological evaluation in Cameroon, with the exception of the Block Design test (WISC-IV) and a Verbal Phonemic Fluency test. A factor analysis shows a division of the tests in a four-factors model that is very consistent with the expected measures of the tests. Effects of gender, age, and education are also discussed. CONCLUSION: this study is the first to report normative data on neuropsychological tests among children in Cameroon and constitutes an initial step for the advancement of neuropsychology in this country in particular and in sub-Saharan Africa in general. The battery is currently used in Cameroon with children suffering from Sickle Cell Disease as an aid to detect cerebrovascular complications.