Stroke is now experienced as a global pandemic. The severity of stroke is based not only on its mortality but especially on the resulting disabilities, including cognitive impairment. Post-stroke cognitive impairment defined as cognitive decline occurring 3 months after stroke due to neuroanatomical changes in cerebral strategic areas is common in stroke survivors while their underlying mechanisms are not completely elucidated [1] [2] . It is estimated that 64% of stroke survivors develop cognitive impairment [3] with deplorable consequences for their socio-professional future. Despite this, post-stroke cognitive disorders are underdiagnosed and underestimated in favor of motor disorders which come first in the majority of cases. Epidemiological data of PSCI are divergent, due to methodological approaches of studies. But there is, at least, an agreement on their high frequency. In Europe, particularly in Britain, the prevalence of cognitive impairment 3 months after stroke was estimated at 24% [4] . In Holland out of 176 subjects assessed 6 months after stroke, the prevalence of cognitive impairment was estimated at 70% [5] ; in Norway, 57% of survivors had developed cognitive impairment 1 year after having a stroke [6] . In the USA out of 212 subjects included in the Framingham study, 19.3% had developed cognitive impairment 10 years after stroke [7] . In Africa, in Nigeria, the CogFast study noted a prevalence of 48.3% of cognitive impairment 3 months after stroke [8] .

A large number of risk factors including the neuroanatomical and neuroimaging characteristics of the stroke, the pre-existing and co-existing cardiovascular risk factors as well as the clinical and demographic characteristics of the patient contribute to the pathogenesis of post-stroke cognitive impairment [9] . Identifying these risk factors in the acute phase and managing them where possible can help improve the cognitive profile of stroke survivors. Considering the stroke increasing incidence in low to middle-income countries including DRC, the current study aims to evaluate the neuropsychological profile of patients 3 months after their stroke as well as the determinants of cognitive disorders occurring within the same period.

A total of 86 patients were selected for our study. The average age was 58.5 (49 - 67), the male gender was more representative, sociodemographic, and para-clinical variables had been searched (Table 1).

Indeed, three-quarters of patients had an occupation (76.7%) and nearly nine out of ten patients had at least 7 years of study (91.9). With regard to clinical and para-clinical history, Table 1 shows that at least one patient in five had smoked in the past (18.6%), and nearly seven patients had a history of alcohol intake (69.8%). In addition, at the time of admission to the emergency room, at least five out of ten patients had chronic hypertension (54.7%), and nearly six out of ten diseases had an altered state of consciousness (61.6%Ischemic stroke was the most common form (70.9%). Finally, the analysis of CT images of stroke patients revealed that the subcortical region was the most affected (66.3%). The left hemispheric localization was the most encountered (72.1%) and involvement of the basivertebral territory was found in one patient in five (20.6%).

The study showed that cognitive disorders in survivors were observed in 79.1% of cases in the 1st month after stroke, and their proportions were reduced

3 months later to 54.7% (Table 2). The severity of cognitive impairment decreased from 16.3% to 4.7% from the 1st to 3rd month after stroke (Table 3).

Furthermore, Table 4 summarizes the analysis of the homogeneity of explanatory variables in patient groups. It shows that the distribution of explanatory variables such as age, sex, and schooling was not homogeneous in the two groups (p > 0.05). On the other hand, only chronic hypertension, alcohol consumption, and MOCA impairment in the first month at admission were homogeneously distributed in both groups (p < 0.01) (Table 4).

PSCI predictors are shown in Table 5. Female patients and patients with chronic hypertension had respectively 86 times (ORA = 86.3; IC 2.8 - 2643.7; p = 0.01) and 36 times (ORA = 26.8; CI_95% 2.55 - 282.55; p < 0.01) at risk of developing PSCI. Patients with pathological lipid profile and pathological MOCA in the first month were respectively 8 times (ORA = 8.7; CI_95% 1.10 - 68.82; p < 0.01) and 41 times (ORA = 41.2; CI_95% 8.13 - 2134.8; p = 0.021) more exposed to PSCI (Table 5).

This study presented an evaluation of cognitive performance using MOCA among post-stroke survivors in the first and third months after stroke. Our results showed that post-stroke cognitive impairment was common in many survivors, especially in the first moments after stroke, with proportions of impaired patients varying from 79.1% in the first month to 54.7% in the third month after stroke, as reported by Rasquin et al. during the same period [5] . This high prevalence is due, on the one hand to the acute neuroanatomic lesions underlying the stroke, including cerebral hypoperfusion, cytotoxic and vasogenic edema, brain neurotransmission disturbances, hyperglycemia, and neuroinflammation, and on the other to patient pre-existing specific factors, including (age, high blood pressure, diabetic…). Three months after the stroke, cognitive disorders decreased from 79.1% to 54.7% slightly higher than the findings of some authors among which Akinyemi et al. [8] and Tu et al. [11] but lower than Yu et al. [12] . This decrease in PSCI is probably related to the effects of early management or functionally dynamic factors in the acute phase of the stroke mentioned above.

Our study confirms previous reports that female status is associated with PSCI [13] [14] . It should be noted that in many countries around the world women’s literacy is not yet universally accepted, in sub-African countries where women have difficulty accessing higher education. This implies a fairly limited cognitive reserve [15] which easily exposes them to cognitive decline in the face of a major brain attack such as a stroke.

As Jacquin et al. and Salvadori E et al. [1] [16] our study confirms that a poor MOCA score in the first month is one of the strongest predictors of PSCI in the 3rd month.

High blood pressure and cognitive function have long been the subject of several controversies. Seux et al. [17] highlighted the negative impact of chronic hypertension on intellectual abilities in a review. This impact may occur through micros infarctions or damage to white matter caused by hypertension. Our study showed a significant association between hypertension and poorer cognitive performance. As the most common risk factor for stroke, hypertension is associated with an increased risk of stroke and by extension stroke-related cognitive impairments. In addition to the severity of increased blood pressure, the duration of the hypertensive state would be an important determinant of cognitive impairment through micros infarctions or damage to white matter [18] . High serum LDL and Triglyceride levels were identified as cognitive impairment predictors in the 3rd month post-stroke, as reported in several studies [19] . The risk of cognitive disorders after acute ischemic stroke increases with increased cholesterol levels. Dyslipidemia is not only an independent and maybe the most important risk factor for ischemic stroke, which tends to cause hidden, progressive, and somatic organic damage, but also affects the cognitive function of patients with ischemic stroke through accelerating systemic atherosclerosis, and it is believed to be a risk factor inducing cognitive disorders, even dementia [20] . This study had some limitations, including not being able to specify in great detail the previous cognitive status of stroke survivors. Our sample was also small because of financial difficulties that did not allow us to perform all the examinations, especially those of an inflammatory nature (cytokines, CRP...) that could also justify post-stroke cognitive disorders.

In addition to the burden of the stroke itself, many burdens of stroke is due to its complications, including cognitive impairments. Cognitive disorders due to their high frequency, severity, and consequences should be sought as well as associated with stroke at the first moment to manage them early at best to prevent them.

Ethical clearance was obtained from the Ethics Committees of the Kinshasa School of Public Health (reference number: ESP/CE/01B/2018). Consent was obtained from each respondent during data collection. Privacy and confidentiality were maintained throughout the study.

All data and supporting documents for this study are available at the Department of Neurology, University of Kinshasa. They will be made available upon request to the leading author.

Ken Mwamba designed the study, collected data, written and submitted a manuscript. Benito Kazenza wrote the statistical plane, cleaned, and analyzed the data. Benjamin Longo Mbenza reviewed and approved the manuscript. Tharcisse Kayembe Kalula reviewed and approved the manuscript. Marie Thérèse Sombo Ayanne reviewed and approved the manuscript. Guy Bumoko designed the study, supervised data collection, and reviewed, and approved the manuscript.

The authors acknowledge the Department of Neurology of the University of Kinshasa for permission granted and three Hospitals of Kinshasa where we collected data.

The authors declare that they have no competing interests.

Mwamba, K., Kazenza, B., Mbenza, B.L., Kalula, T.K., Ayanne, M.T.S. and Bumoko, G. (2023) Evolving Profile and Determinants of Post-Stroke Cognitive Impairment in the 3rd Month among Kinshasa’s Survivors (Democratic Republic of the Congo). World Journal of Neuroscience, 13, 160-172. https://doi.org/10.4236/wjns.2023.133011