Publications by authors named "Joel Kramer"
Objective: The 2024 Alzheimer's Association (AA) research diagnostic criteria for Alzheimer's Disease (AD) considers fluid biomarkers, including promising blood-based biomarkers for detecting AD. This study aims to identify dementia subtypes and their cognitive and neuroimaging profiles in older adults with dementia in the Democratic Republic of Congo (DRC) using biomarkers and clinical data.
Methods: Forty-five individuals with dementia over 65 years old were evaluated using the Community Screening Instrument for Dementia and the informant-based Alzheimer's Questionnaire.
Introduction: Diffusion tensor image analysis along the perivascular space (DTI-ALPS) index was proposed for assessing glymphatic clearance function. This study evaluated DTI-ALPS as a biomarker for cerebral small vessel disease (cSVD) related vascular cognitive impairment and dementia (VCID).
Methods: Four independent cohorts were examined.
Introduction: Placental growth factor (PlGF) may regulate cerebrovascular permeability. We hypothesized that white matter interstitial fluid accumulation, estimated via magnetic resonance imaging (MRI) free water (FW), would explain the associations between elevated PlGF, white matter hyperintensities (WMH), and cognitive impairment.
Methods: MarkVCID consortium participants ≥55 years old with plasma PlGF and brain MRI were included.
This study aimed to compare objective circadian rest-activity-rhythm (RAR) measures with self-reported circadian behavior and morning-evening preference in cognitively healthy older men and women. A total of 129 participants (ages 65-90) completed the Horne & Ostberg Morning-Eveningness Questionnaire (MEQ) and the Circadian Type Inventory (CTI) to assess their morning-evening preference and circadian traits, including rigidity, vigor, languidness, and flexibility. These subjective measures were compared to objective actigraphy data from a sub-cohort of 70 individuals who wore actigraphy watches for 24 hours a day over a 7-day period.
View Article and Find Full Text PDFBackground: Western countries have provided reference values (RV) for Alzheimer's disease (AD) plasma biomarkers, but there are not available in Sub-Saharan African populations.
Objective: We provide preliminary RV for AD and other plasma biomarkers including amyloid- (Aβ42/40), phosphorylated tau-181 and 217 (p-tau181, p-tau217), neurofilament light (Nfl), glial fibrillary acidic protein (GFAP), interleukin 1b and 10 (IL-1b and IL-10) and tumor necrosis factor (TNFα) in Congolese adults with and without dementia.
Methods: 85 adults (40 healthy and 45 dementia) over 50 years old were included.
Based on historic observations that children with reading disabilities were disproportionately both male and non-right-handed, and that early life insults of the left hemisphere were more frequent in boys and non-right-handed children, it was proposed that early focal neuronal injury disrupts typical patterns of motor hand and language dominance and in the process produces developmental dyslexia. To date, these theories remain controversial. We revisited these earliest theories in a contemporary manner, investigating demographics associated with reading disability, and in a subgroup with and without reading disability, compared structural imaging as well as patterns of activity during tasks of verb generation and non-word repetition using magnetoencephalography source imaging.
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- Aberrant angiogenesis may contribute to cognitive decline and could serve as a therapeutic target for dementia prevention, though most prior studies have focused on animal models.
- This study evaluated the relationship between blood markers of angiogenesis and cognitive aging in a sample of 435 older adults, revealing significant associations that varied by sex, particularly in younger women compared to men.
- Results indicated that higher levels of certain angiogenic markers were linked to better executive function and less brain atrophy, suggesting the potential for targeting angiogenesis in addressing age-related cognitive impairment.
Background: Peak-width of skeletonized mean diffusivity (PSMD), a neuroimaging marker of cerebral small vessel disease (SVD), has shown excellent instrumental properties. Here, we extend our work to perform a biological validation of PSMD.
Methods: We included 396 participants from the Biomarkers for Vascular Contributions to Cognitive Impairment and Dementia (MarkVCID-1) Consortium and three replication samples (Cohorts for Heart and Aging Research in Genomic Epidemiology = 6172, Rush University Medical Center = 287, University of California Davis Alzheimer's Disease Research Center = 567).
Reward processing involves evaluation of stimuli to inform what an individual works to pursue or avoid. Patients with behavioral variant frontotemporal dementia (bvFTD) often display reward processing changes, including insensitivity to aversive stimuli. It is unknown how early in the disease course reward changes are detectable.
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- Semantic dementia (SD) patients, particularly those with semantic variant primary progressive aphasia (svPPA) and semantic behavioral variant frontotemporal dementia (sbvFTD), exhibit challenges in identifying faces due to atrophy in the anterior temporal lobe (ATL).
- The study involved 74 SD patients and 36 healthy controls, who underwent various face recognition and semantic processing tests, alongside structural MRI scans to assess neural correlates.
- Findings indicated that while both patient groups struggled with semantic face tasks, they performed similarly on perceptual face tests, suggesting that perceptual deficits may not arise until later stages of the disease with more extensive ATL atrophy.
Article Synopsis
- The human face is essential for expressing emotions and social interaction, but the brain's structural connections to these facial expressions are still unclear.
- A study of 55 older adults linked specific facial behaviors, like frowning or smiling during emotional videos, to increased gray matter volume in brain regions associated with emotional and motor functions.
- The results indicate that both emotional and motor brain networks physically represent facial expressions, highlighting the midcingulate cortex's role in coordinating these facial movements during emotions.
Article Synopsis
- Moral decisions often involve tough choices where sometimes helping many people means harming a few.
- Most research shows that being utilitarian (choosing the most good for the most people) can mean being less sensitive to others' feelings.
- A study of a person with a brain issue showed they still made selfless choices that helped others, suggesting not everyone with this condition is unfriendly.
Objective: The hippocampus is one of the first brain structures affected by Alzheimer's disease (AD), and its atrophy is a strong indicator of the disease. This study investigates the ability of plasma biomarkers of AD and AD-related dementias-amyloid-β (Aβ42/40), phosphorylated tau-181 (p-tau181), neurofilament light (NfL), and glial fibrillary acidic protein (GFAP)-to predict hippocampal atrophy in adult individuals in Kinshasa, Democratic Republic of Congo (DRC).
Methods: Eighty-five adult individuals (40 healthy and 45 suspected AD) over 65 years old were evaluated using the Community Screening Instrument for Dementia and Alzheimer's Questionnaire (AQ).
Article Synopsis
- - Cardiovascular health, evaluated through Life's Simple 7 (LS7), is linked to slower cognitive decline and better brain integrity in patients with autosomal dominant frontotemporal lobar degeneration (FTLD).
- - A study involving 247 FTLD genetic variant carriers and 189 non-carrier controls found that those with better cardiovascular health had slower memory and language declines, as well as less accumulation of frontal white matter hyperintensities (WMHs).
- - Maintaining good cardiovascular health could be a key modifiable strategy to improve cognitive outcomes and brain health in individuals at risk for genetic forms of dementia.
Background: Western countries have provided reference values (RV) for Alzheimer's disease (AD) plasma biomarkers, but there are not available in Sub-Saharan African populations.
Objective: We provide preliminary RV for AD and other plasma biomarkers including amyloid- β (Aβ42/40), phosphorylated tau-181 and 217 (p-tau181, p-tau217), neurofilament light (Nfl), glial fibrillary acidic protein (GFAP), interleukin 1b and 10 (IL-1b and IL-10) and tumor necrosis factor α (TNFα) in Congolese adults with and without dementia.
Methods: 85 adults (40 healthy and 45 dementia) over 50 years old were included.
Article Synopsis
- Some sports and repeated head injuries (like playing football) might lead to brain problems later in life, especially conditions like Frontotemporal Dementia (FTD) and Primary Progressive Aphasia (PPA).
- Researchers compared people with FTD/PPA to healthy ones to see how many had Traumatic Brain Injuries (TBI) and head impacts.
- They found that people with FTD/PPA had more sports experience causing head impacts, and those with a history of head injuries had symptoms show up earlier than those without.
Subjective cognitive concerns (SCC) are common even in cognitively normal older adults who lack objectively-detectable deficits on standard neuropsychological evaluation. The clinical relevance of these concerns, particularly considering the nature of concerns (e.g.
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- The paper addresses cognitive impairment and dementia under-recognition, emphasizing the need for primary care interventions like the TabCAT-BHA to enhance diagnosis.
- The study employs a mixed-methods design in 26 Kaiser Permanente clinics to evaluate the effectiveness of the intervention in improving cognitive impairment detection among older patients.
- Key outcomes focus on diagnosis rates, standardized assessments, and the implementation's acceptability and feasibility based on insights from healthcare leaders.
Introduction: Alzheimer's disease (AD) neuropathological changes present with amnestic and nonamnestic (atypical) syndromes. The contribution of comorbid neuropathology as a substratum of atypical expression of AD remains under investigated.
Methods: We examined whether atypical AD exhibited increased comorbid neuropathology compared to typical AD and if such neuropathologies contributed to the accelerated clinical decline in atypical AD.
Article Synopsis
- Semantic dementia (SD) patients, including those with semantic variant primary progressive aphasia (svPPA) and semantic behavioral variant frontotemporal dementia (sbvFTD), struggle with identifying faces and known individuals due to right anterior temporal lobe (ATL) atrophy, but the presence of perceptual deficits in face recognition is still uncertain.
- A study involving 74 SD patients and 36 cognitively healthy controls used a series of face processing tests and MRI scans to investigate the relationship between face recognition performance and brain structure.
- Results showed that both svPPA and sbvFTD patients had significant impairments in semantic face processing tasks, but they performed well on perceptual face recognition tests, indicating that perceptual abilities
Cerebrovascular disease (CVD) and Alzheimer's disease (AD) often co-occur and may impact specific cognitive domains. This study's goal was to determine effects of CVD and AD burden on cross-sectional and longitudinal executive function (EF) and memory in older adults. Longitudinally followed participants from the National Alzheimer Coordinating Center database (n = 3342) were included.
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- Vascular contributions to cognitive impairment and dementia (VCID) significantly impact cognitive decline in older adults, leading to a study on cerebrovascular reactivity (CVR) and cognitive function across three sites with 263 participants.
- The study used MRI to assess CVR through a carbon dioxide inhalation method and evaluated cognition using the Montreal Cognitive Assessment (MoCA) and executive function metrics.
- Results showed a positive correlation between CVR and both global cognitive scores and executive functioning, confirming CVR as a potential biomarker for VCID across multiple independent sites.
Article Synopsis
- In frontotemporal lobar degeneration (FTLD), abnormal protein buildup in the brain correlates with declines in social-emotional and language skills, primarily involving TDP-43 or tau proteins.
- The study investigates how degeneration patterns in FTLD relate to gene expression of recently evolved genetic regions, using neuroimaging and transcriptomic data to examine targeted brain areas.
- Results indicate that FTLD subtypes uniquely or overlappingly affect brain regions tied to genes evolved in humans, with a notable relationship between TDP-43 function impairment and cryptic splicing in affected genes.
Background: Frontotemporal lobar degeneration (FTLD) is a leading cause of dementia in individuals aged <65 years. Several challenges to conducting in-person evaluations in FTLD illustrate an urgent need to develop remote, accessible, and low-burden assessment techniques. Studies of unobtrusive monitoring of at-home computer use in older adults with mild cognitive impairment show that declining function is reflected in reduced computer use; however, associations with smartphone use are unknown.
View Article and Find Full Text PDFHead-to-Head Comparison of Tau and Amyloid Positron Emission Tomography Visual Reads for Differential Diagnosis of Neurodegenerative Disorders: An International, Multicenter Study.
Ann Neurol
September 2024
Objective: We compared the accuracy of amyloid and [F]Flortaucipir (FTP) tau positron emission tomography (PET) visual reads for distinguishing patients with mild cognitive impairment (MCI) or dementia with fluid biomarker support of Alzheimer's disease (AD).
Methods: Participants with FTP-PET, amyloid-PET, and diagnosis of dementia-AD (n = 102), MCI-AD (n = 41), non-AD diseases (n = 76), and controls (n = 20) were included. AD status was determined independent of PET by cerebrospinal fluid or plasma biomarkers.