Sensitivity of the African neuropsychology battery memory subtests and learning slopes in discriminating APOE 4 and amyloid pathology in adult individuals in the Democratic Republic of Congo

Background

The current study examined the sensitivity of two memory subtests and their corresponding learning slope metrics derived from the African Neuropsychology Battery (ANB) to detect amyloid pathology and APOEε4 status in adults from Kinshasa, the Democratic Republic of the Congo.

Methods

85 participants were classified for the presence of β-amyloid pathology and based on allelic presence of APOEε4 using Simoa. All participants were screened using CSID and AQ, underwent verbal and visuospatial memory testing from ANB, and provided blood samples for plasma Aβ42, Aβ40, and APOE proteotype. Pearson correlation, linear and logistic regression were conducted to compare amyloid pathology and APOEε4 status with derived learning scores, including initial learning, raw learning score, learning over trials, and learning ratio.

Results

Our sample included 35 amyloid positive and 44 amyloid negative individuals as well as 42 without and 39 with APOEε4. All ROC AUC ranges for the prediction of amyloid pathology based on learning scores were low, ranging between 0.56-0.70 (95% CI ranging from 0.44-0.82). The sensitivity of all the scores ranged between 54.3-88.6, with some learning metrics demonstrating good sensitivity. Regarding APOEε4 prediction, all AUC values ranged between 0.60-0.69, with all sensitivity measures ranging between 53.8-89.7. There were minimal differences in the AUC values across learning slope metrics, largely due to the lack of ceiling effects in this sample.

Discussion

This study demonstrates that some ANB memory subtests and learning slope metrics can discriminate those that are normal from those with amyloid pathology and those with and without APOEε4, consistent with findings reported in Western populations.

The Association of Alzheimer's Disease-Related Blood-Based Biomarkers with Cognitive Screening Test Performance in the Congolese Population in Kinshasa

BACKGROUND

Alzheimer's disease (AD), the most common cause of dementia, poses a significant global burden. Diagnosis typically involves invasive and costly methods like neuroimaging or cerebrospinal fluid (CSF) biomarker testing of phosphorylated tau (p-tau) and amyloid-β42/40 (Aβ42/40). Such procedures are especially impractical in resource-constrained regions, such as the Democratic Republic of Congo (DRC). Blood-based biomarker testing may provide a more accessible screening opportunity.

OBJECTIVE

This study aims to examine if AD-related blood-based biomarkers are associated with cognitive test performance in the Congolese population, where limited research has been conducted.

METHODS

In this cross-sectional study of 81 Congolese individuals, cognitive assessments (Alzheimer's Questionnaire (AQ) and Community Screening Interview for Dementia (CSID)) distinguished dementia cases from controls. Blood draws were taken to assess p-tau 181 and Aβ42/40 biomarkers. Relationships between the biomarkers and cognitive performance were analyzed using multiple linear regression models.

RESULTS

Lower plasma Aβ42/40 was significantly associated with lower CSID scores and higher AQ scores, indicative of AD (p < 0.001). These relationships were observed in healthy controls (CSID p = 0.01, AQ p = 0.03), but not in dementia cases. However, p-tau 181 did not exhibit significant associations with either measure. Factors such as age, sex, education, presence of APOEɛ4 allele, did not alter these relationships.

CONCLUSIONS

Understanding relationships between AD-related screening tests and blood biomarkers is a step towards utilization of blood-based biomarker tests as a screening tool for AD, especially in resource-limited regions. Further research should be conducted to evaluate blood biomarker test efficacy in larger samples and other populations.

The Association of Alzheimer's Disease-related Blood-based Biomarkers with Cognitive Screening Test Performance in the Congolese Population in Kinshasa

Background

Alzheimer's Disease (AD), the most common cause of dementia, poses a significant global burden. Diagnosis typically involves invasive and costly methods like neuroimaging or cerebrospinal fluid (CSF) biomarker testing of phosphorylated tau (p-tau) and amyloid-β42/40 (Aβ42/40). Such procedures are especially impractical in resource-constrained regions, such as the Democratic Republic of Congo (DRC). Blood-based biomarker testing may provide a more accessible screening opportunity.

Objective

This study aims to examine if AD-related blood-based biomarkers are associated with cognitive test performance in the Congolese population, where limited research has been conducted.

Methods

In this cross-sectional study of 81 Congolese individuals, cognitive assessments (Alzheimer's Questionnaire (AQ) and Community Screening Interview for Dementia (CSID)) distinguished dementia cases from controls. Blood draws were taken to assess p-tau 181 and Aβ42/40 biomarkers. Relationships between the biomarkers and cognitive performance were analyzed using multiple linear regression models.

Results

Lower plasma Aβ42/40 was significantly associated with lower CSID scores and higher AQ scores, indicative of AD (p<0.001). These relationships were observed in healthy controls (CSID p=0.01, AQ p=0.03), but not in dementia cases. However, p-tau 181 did not exhibit significant associations with either measure. Factors such as age, sex, education, presence of APOE e4 allele, did not alter these relationships.

Conclusion

Understanding relationships between AD-related screening tests and blood-biomarkers is a step towards utilization of blood-based biomarker tests as a screening tool for AD, especially in resource-limited regions. Further research should be conducted to evaluate blood biomarker test efficacy in larger samples and other populations.

Association of plasma biomarkers with cognitive function in persons with dementia and cognitively healthy in the Democratic Republic of Congo

Introduction

This study investigates whether plasma biomarkers (Aβ42/40 and p-tau 181), APS, as well as apolipoprotein E (APOE) proteotype predict cognitive deficits in elderly adults from the Democratic Republic of Congo.

Methods

Forty-four with possible AD (pAD) and 41 healthy control (HC) subjects were screened using CSID and AQ, underwent cognitive assessment with the African Neuropsychology Battery (ANB), and provided blood samples for plasma Aβ42, Aβ40, Aβ42/40, and APOE proteotype. Linear and logistic regression were used to evaluate the associations of plasma biomarkers with ANB tests and the ability of biomarkers to predict cognitive status.

Results

Patients with pAD had significantly lower plasma Aβ42/40 levels, higher APS, and higher prevalence of APOE E4 allele compared to HC. Groups did not differ in levels of Aβ40, Aβ42, or P-tau 181. Results showed that Aβ42/40 ratio and APS were significantly associated with African Naming Test (ANT), African List Memory Test (ALMT), and African Visuospatial Memory Test (AVMT) scores, while the presence of APOE E4 allele was associated with ANT, ALMT, AVMT, and APT scores. P-tau 181 did not show any significant associations while adjusting for age, education, and gender. APS showed the highest area under the curve (AUC) value (AUC = 0.78, 95% confidence interval [CI]: 0.68-0.88) followed by Aβ42/40 (AUC = 0.75, 95% CI: 0.66-0.86) and APOE E4 (AUC = 0.69 (CI 0.57-0.81) in discriminating pAD from HC.

Discussion

These results demonstrate associations between select plasma biomarker of AD pathology (Aβ42/40), APS, and APOE E4 allele) and ANB test scores and the ability of these biomarkers to differentiate pAD from cognitively normal SSA individuals, consistent with findings reported in other settings.

Performance on the African neuropsychology battery using the learning ratio in a sample of healthy Congolese

OBJECTIVE

Using the African Neuropsychology Battery (ANB), we seek to develop normative data by examining the demographic effects for two learning process scores: initial learning (Trial One) and learning ratio (LR, the percentage of items learned relative of to-be-learned material following Trial 1).

METHODS

Healthy participants from the Democratic Republic of Congo completed the four memory tests of the ANB: the African Story Memory Test (ASMT), African List Memory Test (ALMT), African Visuospatial Memory Test (AVMT), and African Contextual Visuospatial Memory Test (ACVMT). We developed indices of learning for each subtest, as well as aggregate learning indices for Trial 1 and LR, and composite indices examining verbal, visual, contextual, and noncontextual learning, and grand indices comprising all four subtests.

RESULTS

Trial 1 and LR scores each demonstrated acceptable intercorrelations across memory tests. We present normative data for Trial 1 and LR by age and education.

CONCLUSION

These data provide normative standards for evaluating learning in Sub-Saharan Africa.

Association Between Hippocampal Volume and African Neuropsychology Memory Tests in Adult Individuals with Probable Alzheimer's Disease in Democratic Republic of Congo

BACKGROUND

Western studies indicate potential associations between hippocampal volume and memory in the trajectory of Alzheimer's disease (AD). However, limited availability of neuroimaging technology and neuropsychological tests appropriate for sub-Saharan African (SSA) countries makes it difficult to establish neuroanatomical associations of hippocampus and memory in this locale.

OBJECTIVE

This study examined hippocampal volumes and memory in healthy control (HC) and probable AD groups in the Democratic Republic of Congo (DRC).

METHODS

Forty-six subjects with probable AD and 29 HC subjects were screened using the Community Instrument for Dementia and the Alzheimer Questionnaire. Participants underwent neuroimaging in Kinshasa, DRC, and memory was evaluated using the African Neuropsychology Battery (ANB). Multiple linear regression was used to determine associations between hippocampal volumes and memory.

RESULTS

Patients with probable AD performed significantly worse than HCs on ANB memory measures, and exhibited greater cerebral atrophy, which was significantly pronounced in the medial temporal lobe region (hippocampus, entorhinal cortex). Both AD and HC subjects exhibited high rates of white matter hyperintensities compared to international base rate prevalence, which was significantly worse for probable AD. Both also exhibited elevated rates of microhemorrhages. Regression analysis demonstrated a significant association between hippocampal volume and ANB memory tests. Hippocampal atrophy discriminated probable AD from the HC group.

CONCLUSIONS

This study establishes the feasibility of conducting neuroimaging research in the SSA, demonstrates many known neuroimaging findings in probable AD patients hold up using culturally appropriate memory tasks, and suggest cardiovascular problems are a greater issue in SSA than in Western countries.

A mixed-method process evaluation of an East Midlands county summer 2021 holiday activities and food programme highlighting the views of programme co-ordinators, providers, and parents

Background

The Holiday Activities and Food (HAF) Programme is a UK Government initiative created to alleviate food insecurity and promote health and well-being among children and their families, who are eligible for Free School Meals (FSM), during the school holidays. This process evaluation investigated factors that facilitated and acted as a barrier to the delivery of the HAF Programme from the perspectives of key stakeholders (Co-ordinators, Providers, and Parents) involved in the HAF Programme across an East Midlands county.

Methods

This evaluation utilized a mixed-methods approach, incorporating focus groups and online surveys to gain rich, multifaceted data. The focus groups were analyzed using a hybrid inductive-deductive thematic analysis and the online surveys were analyzed using mixed-methods approach due to the variation in question type (i.e., quantitative, Likert scale and open response) to align themes to the Government Aims and Standards of the HAF Programme.

Findings

The stakeholders highlighted several factors that facilitated and acted as a barrier to the delivery of the HAF Programme. Facilitating factors included existing and maintaining relationships between Co-ordinators, Providers, and facilities/schools/communities as this improved communication and attendance. Additionally, transport provision for those attending the Programme helped overcome barriers to attendance. The primary barrier of the Programme was the late awarding of the Programme contract as this limited the time available to prepare and organize the Programme. This in turn, had several "knock on" effects that created more barriers and resulted in some of the Government Aims and Standards not being met such as, nutrition education for children and parents. Despite the challenges faced, Co-ordinators and Providers were able to deliver the Programme and positively impact upon the children and their families that attended the Programme.

Conclusion

Following the facilitators and barriers that were highlighted in this evaluation, several recommendations have been made to enhance the delivery of the HAF Programme and ensure Government Aims and Standards, to improve children and family's health and well-being, are attained.

African Enculturation and Performance on the African Neuropsychological Battery

Objective

To test a core assumption of the African Neuropsychology Battery (ANB) that greater African enculturation is associated with better performance.

Method

Subjects were 27 African immigrants to the U.S. [mean age = 39 (SD = 11.5), mean education = 16.3 years (SD = 2.9)], 32 African-Americans [mean age = 34.0 (SD = 11.2), mean education = 16.2 (SD = 2.5)], and 21 U.S. Caucasians [mean age = 45.7 (SD = 13.8), mean education = 17.2 (SD = 2.3)]. All subjects completed a questionnaire on familiarity with elements of African culture. The ANB was administered one-on-one, by trained technicians, in English, in a single session. ANB tests measured visuospatial perception, naming, memory, and abstract reasoning utilizing content drawn from sub-Saharan African cultures.

Results

Groups differed significantly in age (p < .05), but not education or gender, and age was used as a covariate in subsequent group comparisons. African immigrants showed highest African enculturation, followed by African Americans, and Caucasians [F(2, 74) = 36.16, p < .000], with all groups differing significantly from one another in post-hoc comparisons (p < .02). African enculturation correlated significantly only with ability to identify pictures of African fruits (Pearson r = .58, p < .001) and objects (r = .25, p < .03). Analysis of Covariance followed by Bonferroni post-hoc comparisons confirmed that African immigrants were superior to Caucasians (p < .001) and African-Americans (p < .001) in identifying fruits, with the latter two groups not differing significantly from one another. African immigrants were superior to Caucasians in object identification (p < .05), but did not differ significantly from African-Americans.

Conclusions

African enculturation influences performance on some ANB tests and results support the potential of the ANB to assess performance in a less culturally-biased manner in African immigrants.

Respiratory disease and sero-epidemiology of respiratory pathogens in the working horses of Ethiopia

BACKGROUND

Pathogens are frequently implicated in equine respiratory disease. In Ethiopia, respiratory disease is a frequent cause for presentation at veterinary clinics and a priority concern for users of working horses. However, there is little existing literature on possible aetiologies.

OBJECTIVES

Determine prevalence of respiratory signs and exposure to major respiratory pathogens through a serological survey.

STUDY DESIGN

Cross-sectional.

METHODS

Systematically selected horses from 19 sites in central Ethiopia were examined clinically and sampled once (August-December 2013). A face-to-face interview collected data on horses' management and history. Serological testing targeted equine influenza virus (EIV), equine herpesviruses-1 (EHV-1) and -4 (EHV-4), equine rhinitis viruses A (ERAV) and B (ERBV), equine arteritis virus (EAV) and Streptococcus equi subspecies equi (S. equi).

RESULTS

Owners reported a recent history of coughing in 38% of horses and nasal discharge in 7%. No animals were observed coughing during examination but 6% had a nasal discharge. Antibodies towards S. equi, were most prevalent (8%, 33/350). Antibodies to EAV were confirmed in one animal (0.3%). Low antibody titres to EHV-1/4 and ERA/BV suggested prior exposure but antibodies to EIV were not detected. Multivariable, multilevel logistic regression analysis for risk factors associated with S. equi serostatus showed higher odds of seropositivity in younger animals and those working less frequently.

MAIN LIMITATIONS

A single serological sample cannot describe dynamic changes in antibodies. Sampling horses at the place of work may result in healthy-worker bias.

CONCLUSIONS

S. equi may be endemic in this population and contributing, in part, to the occurrence of respiratory disease. Low prevalence of antibodies to viruses, with the exception of EIV, indicates these pathogens are present, but unlikely a predominant cause of respiratory signs and noninfectious causes of disease should also be investigated. Working horses in this region would be vulnerable to incursion of equine influenza.

Operative strategies to reduce cerebral embolic events during on- and off-pump coronary artery bypass surgery: A stratified, prospective randomized trial

OBJECTIVE

To determine the impact of different aortic clamping strategies on the incidence of cerebral embolic events during coronary artery bypass grafting (CABG).

METHODS

Between 2012 and 2015, 142 patients with low-grade aortic disease (epiaortic ultrasound grade I/II) undergoing primary isolated CABG were studied. Those undergoing off-pump CABG were randomized to a partial clamp (n = 36) or clampless facilitating device (CFD; n = 36) strategy. Those undergoing on-pump CABG were randomized to a single-clamp (n = 34) or double-clamp (n = 36) strategy. Transcranial Doppler ultrasonography (TCD) was performed to identify high-intensity transient signals (HITS) in the middle cerebral arteries during periods of aortic manipulation. Neurocognitive testing was performed at baseline and 30-days postoperatively. The primary endpoint was total number of HITS detected by TCD. Groups were compared using the Mann-Whitney U test.

RESULTS

In the off-pump group, the median number of total HITS were higher in the CFD subgroup (30.0; interquartile range [IQR], 22-43) compared with the partial clamp subgroup (7.0; IQR, 0-16; P < .0001). In the CFD subgroup, the median number of total HITS was significantly lower for patients with 1 CFD compared with patients with >1 CFD (12.5 [IQR, 4-19] vs 36.0 [IQR, 25-47]; P = .001). In the on-pump group, the median number of total HITS was 10.0 (IQR, 3-17) in the single-clamp group, compared with 16.0 (IQR, 4-49) in the double-clamp group (P = .10). There were no differences in neurocognitive outcomes across the groups.

CONCLUSIONS

For patients with low-grade aortic disease, the use of CFDs was associated with an increased rate of cerebral embolic events compared with partial clamping during off-pump CABG. A single-clamp strategy during on-pump CABG did not significantly reduce embolic events compared with a double-clamp strategy.

Microbiota and their role in the pathogenesis of oral mucositis

Oral mucositis in patients undergoing cancer therapy is a significant problem. Its prevalence ranges between 20 and 100%, depending on treatment type and protocols and patient-based variables. Mucositis is self-limiting when uncomplicated by infection. Unfortunately, the incidence of developing a local or systemic infection during the course of the treatment is very high. At this stage, it is unclear which role oral microbiota play in the onset, duration, and severity of oral mucositis. Nevertheless, there is growing interest in this underexplored topic, and new studies are being undertaken to unravel their impact on the pathogenesis of mucositis.

Cognitive rehabilitation practice patterns: a survey of American Hospital Association Rehabilitation Programs

Results of a survey of cognitive rehabilitation (CRT) practice patterns are reported. Of 270 programs contacted, 45% responded. Most patients were under age 65, had a stroke or brain injury, and underwent individual CRT for attention or memory problems while hospitalized. CRT typically lasted 1-6 months and cost $130 per session. Rehearsal and compensation approaches were employed equally, while computer-based procedures were infrequent. Speech and occupational therapists provided services more than neuropsychologists and few programs incorporated neuropsychological testing. Results suggest opportunities for research and expansion of neuropsychological practice and highlight the need for better communication between researchers and clinicians.

Ethnographic analysis of traumatic brain injury patients in the national Model Systems database

OBJECTIVE

To compare demographics, injury characteristics, therapy service and intensity, and outcome in minority versus nonminority patients with traumatic brain injury (TBI).

DESIGN

Retrospective analysis.

SETTING

Twenty medical centers.

PARTICIPANTS

Two thousand twenty patients (men, n=1,518; women, n=502; nonminority, n=1,168; minority, n=852) with TBI enrolled in the Traumatic Brain Injury Model Systems database.

INTERVENTIONS

Not applicable.

MAIN OUTCOMES MEASURES

Age, gender, marital status, education, employment status, injury severity (based on Glasgow Coma Scale [GCS] admission score, length of posttraumatic amnesia, duration of unconsciousness), intensity (hours) of therapy rendered, rehabilitation length of stay (LOS), rehabilitation charges, discharge disposition, postinjury employment status, FIM instrument change scores, and FIM efficiency scores. Independent sample t tests were used to analyze continuous variables; chi-square analyses were used to evaluate categorical data.

RESULTS

DEMOGRAPHICS

overall, minorities were found to be mostly young men who were single, unemployed, and less well educated, with a longer work week if employed when injured.

ETIOLOGY

motor vehicle crashes (MVCs) predominated as the cause of injury for both groups; however, minorities were more likely to sustain injury from acts of violence and auto-versus-pedestrian crashes. Minorities also had higher GCS scores on admission and shorter LOS. Rehabilitation services: significant differences were found in the types and intensity of rehabilitation services provided; these included physical therapy, occupational therapy, and speech-language pathology, but not psychology.

CONCLUSION

Minority patients who sustain TBI generally tend to be young men with less social responsibility. Although MVCs predominate as the primary etiology, acts of violence and auto-versus-pedestrian incidents are more common in the minority population. Minorities tend to have higher GCS scores at admission. Also, the type and intensity of rehabilitation services provided differed significantly for the various interdisciplinary subspecialties. Rehabilitation charges, discharge disposition, and postinjury employment status were similar for the 2 groups, even though LOS is typically 3 to 4 days shorter for the minority group. A more detailed investigation is warranted to explain these findings.