Dementia and cognitive impairment in French-speaking Sub-Saharan Africa: a comprehensive review on moving out of the shadows of neglect

Dementia is a global public health problem with increasing prevalence and incidence worldwide. The African continent is expected to bear the biggest brunt of the burden of dementia by 2050 because of the rapid demographic changes, including rapid population growth, an increase in life expectancy, and ageing. However, French-speaking Sub-Saharan African (FS-SSA) countries are underrepresented in research on dementia in Africa. While the reasons are diverse and complex, linguistic and cultural barriers to research, disproportionately affect these countries and may be significant factors. Any efforts, therefore, to redress the burden of dementia in Africa must consider the specific demographic, cultural, and linguistic characteristics of FS-SSA countries. This scoping review explores the current state of knowledge in dementia and cognitive impairment in Sub-Saharan Africa, highlighting research gaps and specific patterns unique to FS-SSA Africa. We identify pathways for research to bridge the knowledge gaps on dementia in FS-SSA as part of the global endeavor to tackle dementia worldwide

Hypertension in Cameroon associated with high likelihood of obstructive sleep apnea: a pilot study

Abstract Background Although disordered sleep patterns predispose to hypertension (HTN), little is known on the effect of the latter on sleep patterns in sub-Saharan Africa. This study therefore sought to generate preliminary data on the likelihood (risk) of Obstructive sleep apnea (OSA) in hypertensive patients, with the aid of sleep questionnaires. Methods This case–control study, age-and-sex-matched HTN patients with normotensive participants, and compared sleep patterns in either group determined with the aid of the Berlin Questionnaire (BQ) and Epworth Sleepiness Scale (ESS). Results Overall, 50 HTN and 54 age- and sex-matched normotensive participants were enrolled. The prevalence of snoring was higher in participants with hypertension compared to normotensives (58.0% versus 44.0% respectively), though not significantly, (p = 0.167). However, the hypertensive cases (aged on average 54.78 ± 8.79 years and with mean duration since diagnosis of 4.46 ± 4.36 years) had a significantly higher likelihood of Obstructive Sleep Apnea (OSA) than the controls (aOR = 5.03; 95% CI, 1.90–13.33, p = 0.001) and but no significant resulting daytime sleepiness (p = 0.421). There was no clear trend observed between both the risk of OSA and daytime sleepiness and HTN severity. Although not significant, participants with controlled hypertension had lower rates of risk of OSA compared to those with uncontrolled HTN (50.0% versus 63.2%, p = 0.718). Conclusions Preliminary findings of this study (the first of its kind in Cameroon) suggests that hypertension is positively associated with likelihood of OSA in Cameroon. Further studies are required to investigate this further and the role of sleep questionnaires in our setting, cheap and easy to use tools which can be used to identify early, patients with hypertension in need for further sleep investigations. This will contribute to improving their quality of life and adherence to anti-hypertension treatment

The actigraphy sleep score: a new biomarker for diagnosis, disease staging, and monitoring in human African trypanosomiasis (HAT)

Human African trypanosomiasis (HAT) remains a serious public health problem with diagnostic and treatment challenges in many African countries. The absence of a gold-standard biomarker has been a major difficulty for accurate disease staging and treatment follow-up. We therefore attempted to develop a simple, affordable, and noninvasive biomarker for HAT diagnosis and staging. Simultaneous actigraphy and polysomnography as well as CSF white blood cell (WBC) count, trypanosome presence, and CXCL-10 cytokine levels were performed in 20 HAT patients and nine healthy individuals (controls) using standard procedures. The International HIV Dementia Scale (IHDS) was scored in some patients as a surrogate for clinical assessment. From actigraphic parameters, we developed a novel sleep score and used it to determine correlations with other HAT markers, and compared their performance in differentiating between patients and controls and between HAT stages. The novel actigraphy sleep score (ASS) had the following ranges: 0-25 (healthy controls), 67-103 (HAT stage I), 111-126 (HAT intermediate), and 133-250 (HAT stage II). Compared with controls, stage I patients displayed a 7-fold increase in the ASS (P < 0.01), intermediate stage patients a 10-fold increase (P < 0.001), and HAT stage II patients an almost 20-fold increase (P < 0.001). CXCL-10 showed high interindividual differences. White blood cell counts were only marked in HAT stage II patients with a high interindividual variability. The International HIV Dementia Scale score negatively correlated with the ASS. We report the development and better performance of a new biomarker, ASS, for HAT diagnosis, disease staging, and monitoring that needs to be confirmed in large cohort studies

Clinical presentations of onchocerciasis-associated epilepsy (OAE) in Cameroon

Background: A high prevalence of epilepsy has been observed in several onchocerciasis-endemic countries, including Cameroon. However, little is known on the clinical presentations of the affected persons with epilepsy (PWE). A community-based study was conducted with the aim of describing the spectrum of seizures in selected onchocerciasis-endemic villages in Cameroon and documenting relevant medical history in patients with onchocerciasis-associated epilepsy (OAE). Methods: We carried out door-to-door surveys in 5 onchocerciasis-endemic villages in Cameroon and recruited all consenting PWE. Epilepsy was diagnosed using a 2-step approach consisting of the administration of a standardized 5-item questionnaire followed by confirmation of the suspected cases by a neurologist. Onchocerciasis-associated epilepsy was defined as ≥ 2 seizures without an obvious cause, starting between the ages of 3–18 years in previously healthy persons having resided for at least 3 years in an onchocerciasis-endemic area. Ivermectin use by PWE was verified. Seizure history, relevant past medical, and family history, as well as neurological findings, were noted. Results: In all, 156 PWE were recruited in the 5 villages. The modal age group for epilepsy onset was 10–14 years. The diagnostic criteria for OAE were met by 93.2% of the PWE. Participants had one or more of the following seizure types: generalized tonic–clonic seizures (89.1%), absences (38.5%), nodding (21.8%), focal nonmotor (7.7%), and focal motor seizures (1.9%). One case (0.6%) with the “Nakalanga syndrome” was identified. More than half (56.4%) of PWE had at least one seizure per month. In one village, 56.2% of PWE had onchocercal skin lesions. Conclusion: People with epilepsy in onchocerciasis-endemic villages in Cameroon present with a wide clinical spectrum including nodding seizures and Nakalanga features. A great majority of participants met the diagnostic criteria for OAE, suggesting that better onchocerciasis control could prevent new cases. Epilepsy management algorithms in these areas must be adjusted to reflect the varied seizure types.SCOPUS: ar.jDecretOANoAutActifinfo:eu-repo/semantics/publishe

Epidemiology of onchocerciasis-associated epilepsy in the Mbam and Sanaga river valleys of Cameroon: Impact of more than 13 years of ivermectin

Background: A high epilepsy prevalence has been reported in several onchocerciasis-endemic villages along the Mbam and Sanaga river valleys in Cameroon, including Bilomo and Kelleng. We sought to determine the prevalence of epilepsy in these two villages following more than 13 years of community-directed treatment with ivermectin (CDTI). Methods: Door-to-door surveys were performed on the entire resident population in the villages in August 2017 and January 2018. Epilepsy was diagnosed using a 2-step approach: administration of a standardized 5-item questionnaire followed by confirmation by a neurologist. Previously published diagnostic criteria for onchocerciasis-associated epilepsy (OAE) were used. Ov16 serology was done for children aged 7-10 years to assess onchocerciasis transmission. Findings were compared with previous data from these two villages. Results: A total of 1525 individuals (1321 in Bilomo and 204 in Kelleng) in 233 households were surveyed in both villages. The crude prevalence of epilepsy was 4.6% in Bilomo (2017) and 7.8% in Kelleng (2018), including 12 (15.6% of cases) persons with epilepsy (PWE) with nodding seizures. The age and sex-standardized prevalence in Kelleng decreased from 13.5% in 2004 to 9.3% in 2018 (P < 0.001). The median age of PWE shifted from 17 (IQR: 12-22) years to 24 (IQR: 20-30) years in Bilomo (P < 0.001); and slightly from 24 (IQR: 14-34) years to 28 (IQR: 21.25-36.75) years in Kelleng (P = 0.112). Furthermore, 47.6% of all tested children between 7 and 10 years had Ov16 antibodies. Conclusions: There is a decrease in epilepsy prevalence after 13 years and more of CDTI in both villages. The age-shift observed in PWE suggests that ivermectin may prevent OAE in younger residents. Ov16 seropositivity in children indicates ongoing onchocerciasis transmission possibly due to suboptimal control measures. Our findings support the existence of OAE in Cameroon and highlight the need to strengthen onchocerciasis elimination programs.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Sleep Apnea Syndrome: Prevalence and Comorbidity with Other Non-communicable Diseases and HIV Infection, among Hospitalized Patients in Yaoundé, Cameroon

Background: Sleep apnea syndrome (SAS), a growing public health threat, is an emerging condition in sub-Saharan Africa (SSA). Related SSA studies have so far used an incomplete definition. This study is aimed at assessing SAS using an American Academy of Sleep Medicine (AASM) complete definition and at exploring its relationship with comorbidities, among patients hospitalized in a Cameroonian tertiary hospital. Methods: This cross-sectional study was conducted in cardiology, endocrinology, and neurology departments of the Yaoundé Central Hospital. Patients aged 21 and above were consecutively invited, and some of them were randomly selected to undergo a full night record using a portable sleep monitoring device, to diagnose sleep-disordered breathing (SDB). SAS was defined as an apnea - hypopnea index (AHI) ≥ 5/h, associated with either excessive daytime sleepiness or at least 3 compatible symptoms. Moderate to severe SAS (MS-SAS) stood for an AHI ≥ 15/h. We used chi-square or Fisher tests to compare SAS and non-SAS groups. Findings: One hundred and eleven patients presented a valid sleep monitoring report. Their mean age ± standard deviation (range) was 58 ± 12.5 (28-87) years, and 53.2% were female. The prevalence (95% confident interval (CI)) of SAS was 55.0 (45.7, 64.2)% and the one of MS-SAS 34.2 (25.4, 43.1)%. The obstructive pattern (90.2% of SAS and 86.8% of MS-SAS) was predominant. The prevalence of SAS among specific comorbidities ranged from 52.2% to 75.0%. Compared to SAS free patients, more SAS patients presented with hypertension (75.4% vs. 48.0%, p = 0.005%), history of stroke (36.7% vs. 32.0%, p = 0.756), cardiac failure (23.0% vs. 12.0%, p = 0.213), and combined cardiovascular comorbidity (80.3% vs. 52.0%, p = 0.003). Similar results were observed for MS-SAS. Metabolic and neuropsychiatric comorbidities did not differ between SAS and SAS-free patients. Conclusion: The SAS diagnosed using modified AASM definition showed high prevalence among patients hospitalized for acute medical conditions, as it was found with SDB. Unlike HIV infection, metabolic and brain conditions, cardiovascular comorbidities (hypertension and cardiac failure) were significantly more prevalent in SAS patients.</p

Epilepsy-associated neurocognitive disorders (EAND) in an onchocerciasis-endemic rural community in Cameroon: A population-based case–control study

Epilepsy affects at least 50 million individuals worldwide, especially in sub-Saharan Africa (sSA). Cognitive impairment is common in people with epilepsy (PWE) yet, little is known on the burden of cognitive impairment in people with epilepsy in sSA. This study was thus designed to assess cognitive impairment in PWE or epilepsy- associated neurocognitive disorders (EAND) in a rural population in Cameroon.Methods: This was a case–control study including PWE and age/sex- matched healthy controls from July to September 2017 in Bilomo, a village in the Mbam and Kim Division. The Montreal Cognitive Assessment (MoCA), International HIV Dementia Scale (IHDS), Dubois' Five Word testing, Frontal Assessment Battery (FAB), Isaac's Set Test and the Clock drawing test were administered to the study participants to evaluate global and specific cognitive functions.Results: Eighty participants were included (40 cases and 40 controls) with a mean age of 25.78 years. Using the MoCA, 87.5% of cases had cognitive impairment, against 37.5% of controls (p < 0.001; OR 11.67; CI 3.40–45.09). Using the IHDS, the prevalence of global cognitive impairment was 84.6% among the cases against 40% for the controls (p = < 0.001; OR 7.07; CI 2.29–29.19). Specifically, executive function deficits (92.5% of cases vs 40.0% of controls p = < 0.001 OR = 18.50 CI; 4.48–105.08) and decreased verbal fluency (100% of cases against 45% of controls p < 0.001) were the most affected cognitive domains. Longer duration of epilepsy and higher seizure frequency were associated with global cognitive impairment. Low level of education was associated with both decreased verbal fluency and executive dysfunction while a longer stay in Bilomo correlated with poor results on the Isaac's Set Test.Conclusion: The prevalence of cognitive impairment appears to be much higher in PWE in the Mbam valley, particularly decreased executive function and verbal fluency, than in people without epilepsy. Longer disease duration, higher seizure frequency, low level of education and length of stay in Bilomo are associated with poorer cognitive performance. More studies are needed to refine evaluation tools to better characterize and manage EAND in sSA