This systematic review of literature on the prevalence of cognitive impairment and dementia in sub-Saharan Africa found the estimated prevalence of dementia ranges from 0%, to 10.1% in Nigeria. The estimated prevalence of cognitive impairment ranges from 6.3%, in Nigeria to 25% in the Central African Republic. Estimates of the prevalences of dementia and cognitive impairment in sub-Saharan Africa vary widely.
Mavrodaris, A. Powell, J. [and] Thorogood, M. (2013). Prevalences of dementia and cognitive impairment among older people in sub-Saharan Africa: a systematic review. Bulletin of the World Health Organization, October 1st 2013, Vol.91(10), pp.773-83. (Click here to view the PubMed abstract).