Kremen, Sarah

ABSTRACT Background The brain–heart axis is central to vascular health, yet no imaging biomarkers capture integrated dysfunction across neural and coronary microvascular networks. Although coronary microvascular dysfunction links to cognitive decline, neural correlates connecting cerebral efficiency with coronary physiology remain unclear. Objectives To determine whether the Unified Structural and Functional Connectivity (USFC)—a multimodal magnetic resonance imaging (MRI) “traffic map” of brain network efficiency—predicts coronary endothelial function and cognition in women with ischemia and no obstructive coronary artery disease (INOCA). Methods Thirty‐three women with suspected INOCA from the Women's Ischemia Syndrome Evaluation (WISE) study (NCT03876223) underwent invasive coronary function testing, cardiac MRI, cognitive evaluation, and multimodal brain MRI. USFC, structural connectivity (SC), and functional connectivity (FC) were computed for predefined 10 backbone pathways. Support vector regression and logistic classification assessed predictive performance. Results USFC explained 16%–20% more variance in coronary endothelial function, myocardial perfusion reserve, and cognition than SC or FC alone ( p < 0.05). Connectivity between the left caudate–superior medial orbital gyrus and right calcarine–inferior occipital gyrus emerged as robust predictors of crystallized cognition ( r = –0.78, p FDR < 0.05) and coronary endothelial function ( r = 0.70, p FDR < 0.05), respectively. USFC also best discriminated low versus high coronary blood flow (area under the ROC curve [AUC]: USFC 0.622 vs. SC 0.349 and FC 0.425; p < 0.05). Conclusions USFC identifies neuro–cardiac pathways linking cerebral efficiency with coronary endothelial function. These results introduce a sensitive biomarker of systemic vulnerability, highlighting occipital and frontostriatal pathways as shared substrates of dysfunction. USFC offers a mechanistic framework for detecting vascular risk across metabolically demanding tissues. Trial Registration ClinicalTrials.gov identifier: NCT03876223

Background Motor speech disorders are early, common, and functionally limiting features of atypical parkinsonian disorders (APDs) such as progressive supranuclear palsy (PSP), corticobasal syndrome (CBS), and multiple system atrophy (MSA). These impairments are underrecognized and undertreated in neurology clinics. Objectives This review aims to characterize speech impairment in APDs, offer practical guidance for clinical evaluation, highlight the role of Speech‐Language pathologists (SLPs) in diagnosis and management, and outline current and emerging management strategies. Methods A narrative review was conducted by the Diagnosis and Treatment Working Group of CurePSP's Centers of Care, integrating literature and clinical experience to summarize evaluation, diagnosis, and treatment of motor speech disorders in APDs. Results Speech changes in APDs are often mixed dysarthrias with hypokinetic, spastic, and/or ataxic components, and may include apraxia of speech; these are frequently more severe and progress quicker than in Parkinson's disease. These features can assist in differential diagnosis and should prompt early referral to SLPs. Despite the high prevalence of speech and voice changes, comprehensive assessment of motor speech disorders is uncommon in neurology clinics. Current evidence regarding the efficacy of interventions is mixed. Digital acoustic analysis and neuromodulation offer promising directions for diagnosis and treatment. Conclusions Early, collaborative management of motor speech impairment elevates care in APDs. Neurologists and SLPs must work together to improve recognition, diagnosis, and care. Future research should focus on objective biomarkers and personalized therapies to support communication, autonomy, and quality of life for individuals living with APDs.

Abstract Background Sensitive, accessible biomarkers of the pathologies underlying Alzheimer's disease and related dementias (ADRD) are critical for accurate diagnosis, deeper understanding of disease mechanisms, and development of new therapies with validated target engagement. The retina is connected to the brain via the optic nerve, which may facilitate the transmission and spread of amyloid beta (Aβ) and tau species. In postmortem studies, retinal Aβ deposits have been associated with neuritic Aβ‐plaque and neurofibrillary tangle burden, particularly in the entorhinal and temporal cortices. The goal of the current study was to evaluate associations between retinal perivascular amyloid and cognition, as well as to explore effect modification by hippocampal volumetry. Method Participants, aged ≥40 years, underwent retinal imaging, brain MRI, FDG‐PET, and a comprehensive neuropsychological assessment. Retinal amyloid imaging was conducted following curcumin ingestion and pupil dilation using a confocal scanning laser ophthalmoscope. Perivascular Aβ plaque counts were quantified in the superotemporal peripheral region following manual identification and tracking of retinal arteries and veins. Associations between retinal perivascular Aβ plaque counts with cognitive domains were evaluated using linear regression models adjusted for age, sex, and estimated premorbid functioning. Where significant associations were detected ( p ‐value<0.05), effect modification by hippocampal volumetry was examined with additional adjustment for intracranial volume. Result The sample included 26 participants (mean age 65±7 years, 50% female). Higher amyloid plaque counts in the perivascular secondary small and tertiary branches and in the periarteriolar tertiary branch were associated with poorer verbal and visual memory (Table 1). Significant interactions were observed between amyloid plaque count in the perivascular secondary small branch (β(95% Confidence Interval) = 0.397(0.037‐0.756), p = 0.033) and periarteriolar tertiary branch (β(95% Confidence Interval) = 0.756(0.165–1.346), p = 0.017) with hippocampal volumetry for visual memory. Conclusion Our pilot study provides preliminary evidence that perivascular Aβ accumulation in smaller vessels of the superotemporal retina may be a marker of memory impairment that may interact synergistically with hippocampal atrophy. Longitudinal studies consisting of multimodal ophthalmic assessments, brain imaging, ADRD biofluid markers, and cognitive testing will be necessary to capture the temporal sequence of retinal pathological changes and their associations with those in the brain.

AbstractINTRODUCTIONGiven the close interactions between the retina and the brain, retinal amyloid imaging may serve as a diagnostic and prognostic tool for Alzheimer's disease and related dementias. This retrospective study investigated multivariable associations between retinal perivascular amyloid and cognitive domains.METHODSIntegrated analysis of retinal perivascular amyloid imaging, neuropsychological assessment, and brain magnetic resonance imaging in adults with and without cognitive impairment (N = 26; mean age: 65 ± 7 years; 50% female). Correlations between perivascular amyloid plaque burden and cognitive domains were evaluated with linear regression and interactions with hippocampal volumetry were explored.RESULTSHigher perivascular and periarteriolar amyloid plaque count in the secondary small and tertiary branches were associated with poorer verbal and visual memory in this cohort (p = 0.005–0.009). Higher perivascular amyloid burden interacted with hippocampal atrophy to worsen visual memory (p = 0.033).DISCUSSIONRetinal perivascular amyloid may serve as a non‐invasive marker for cognitive impairment and may shed insight into pathological changes in the brain.Highlights In vivo retinal perivascular amyloid plaque counts are associated with poorer memory. Retinal perivascular amyloid interacted with hippocampal atrophy to worsen memory. Retinal amyloid imaging is a potential biomarker for neurodegenerative diseases.

AbstractBackgroundWomen with suspected coronary microvascular dysfunction (CMD) may be at higher risk of experiencing cognitive decline due to cerebral small vessel disease, a known contributor to Alzheimer’s disease and related dementias (ADRD). A potential underlying mechanism that could accelerate this cognitive decline is the accumulation of brain tissue iron, which has been previously linked to changes in brain function potentially caused by oxidative stress and cell death. Therefore, we aim to elucidate whether a similar mechanism could affect women with suspected CMD by investigating the potential role of iron deposition on the brain’s functional organization and its effect on cognition using advanced magnetic resonance imaging (MRI).Material and MethodsTwenty‐seven women with suspected CMD [Age; median (range) = 54 (29‐76)], drawn from ongoing cohorts (3R01HL146158‐04S1,3U54AG065141‐04S1), underwent a 3T MRI protocol, including submillimeter T2* 3‐dimensional echo‐planar‐imaging for assessing iron deposition with high‐resolution quantitative susceptibility mapping (QSM) and resting‐state fMRI (rs‐fMRI). Iron content was quantified by total‐generalized‐variation based QSM analysis. Functional integrity was determined via graph theoretical approach (i.e., nodal degree). Cognitive assessment was also performed using the NIH Toolbox. Mediation analysis was conducted using Python Statsmodels.ResultsMost of the women with suspected CMD showed lower performance in processing speed, working memory, executive function, and attention (Figure 1A). We found a significant association between elevated iron levels in paracentral gyrus and lower functional connectivity in left hippocampus (p=0.005, adjusted‐r2=0.19) (Figure 1B). Elevated iron level in the paracentral gyrus showed an impact on cognitive performance in the domains of executive function and attention (p<0.0001, coefficient=531.09) as well as language functions and crystalized abilities (p=0.036, coefficient=362.45), mediated by functional connectivity in the left hippocampus (indirect effect on executive function / language: p = 0.034 / 0.038, coefficient = ‐254.54 /‐ 213.06) (Figure 1C).ConclusionsOur results suggest that changes in hippocampal functional organization are associated with cortical iron deposition and mediate its impact on cognitive performances. These changes may increase the risk of cognitive decline/ADRD or in women with suspected CMD. Future research in a larger cohort with a longitudinal design is necessary to validate and expand upon these findings.

AbstractBackgroundWomen with suspected coronary microvascular dysfunction (CMD) may be at higher risk of experiencing cognitive decline due to cerebral small vessel disease, a known contributor to Alzheimer’s disease and related dementias (ADRD). A potential underlying mechanism that could accelerate this cognitive decline is the accumulation of brain tissue iron, which has been previously linked to changes in brain function potentially caused by oxidative stress and cell death. Therefore, we aim to elucidate whether a similar mechanism could affect women with suspected CMD by investigating the potential role of iron deposition on the brain’s functional organization and its effect on cognition using advanced magnetic resonance imaging (MRI).Material and MethodsTwenty‐seven women with suspected CMD [Age; median (range) = 54 (29‐76)], drawn from ongoing cohorts (3R01HL146158‐04S1,3U54AG065141‐04S1), underwent a 3T MRI protocol, including submillimeter T2* 3‐dimensional echo‐planar‐imaging for assessing iron deposition with high‐resolution quantitative susceptibility mapping (QSM) and resting‐state fMRI (rs‐fMRI). Iron content was quantified by total‐generalized‐variation based QSM analysis. Functional integrity was determined via graph theoretical approach (i.e., nodal degree). Cognitive assessment was also performed using the NIH Toolbox. Mediation analysis was conducted using Python Statsmodels.ResultsMost of the women with suspected CMD showed lower performance in processing speed, working memory, executive function, and attention (Figure‐1A). We found a significant association between elevated iron levels in paracentral gyrus and lower functional connectivity in left hippocampus (p = 0.005, adjusted‐r2 = 0.19) (Figure‐1B). Elevated iron level in the paracentral gyrus showed an impact on cognitive performance in the domains of executive function and attention (p<0.0001, coefficient = 531.09) as well as language functions and crystalized abilities (p = 0.036, coefficient = 362.45), mediated by functional connectivity in the left hippocampus (indirect effect on executive function / language: p = 0.034 / 0.038, coefficient = ‐254.54 /‐ 213.06) (Figure‐1C).ConclusionsOur results suggest that changes in hippocampal functional organization are associated with cortical iron deposition and mediate its impact on cognitive performances. These changes may increase the risk of cognitive decline/ADRD or in women with suspected CMD. Future research in a larger cohort with a longitudinal design is necessary to validate and expand upon these findings.

ImportanceIncreased white matter hyperintensity (WMH) volume is a common magnetic resonance imaging (MRI) finding in both autosomal dominant Alzheimer disease (ADAD) and late-onset Alzheimer disease (LOAD), but it remains unclear whether increased WMH along the AD continuum is reflective of AD-intrinsic processes or secondary to elevated systemic vascular risk factors.ObjectiveTo estimate the associations of neurodegeneration and parenchymal and vessel amyloidosis with WMH accumulation and investigate whether systemic vascular risk is associated with WMH beyond these AD-intrinsic processes.Design, Setting, and ParticipantsThis cohort study used data from 3 longitudinal cohort studies conducted in tertiary and community-based medical centers—the Dominantly Inherited Alzheimer Network (DIAN; February 2010 to March 2020), the Alzheimer’s Disease Neuroimaging Initiative (ADNI; July 2007 to September 2021), and the Harvard Aging Brain Study (HABS; September 2010 to December 2019).Main Outcome and MeasuresThe main outcomes were the independent associations of neurodegeneration (decreases in gray matter volume), parenchymal amyloidosis (assessed by amyloid positron emission tomography), and vessel amyloidosis (evidenced by cerebral microbleeds [CMBs]) with cross-sectional and longitudinal WMH.ResultsData from 3960 MRI sessions among 1141 participants were included: 252 pathogenic variant carriers from DIAN (mean [SD] age, 38.4 [11.2] years; 137 [54%] female), 571 older adults from ADNI (mean [SD] age, 72.8 [7.3] years; 274 [48%] female), and 318 older adults from HABS (mean [SD] age, 72.4 [7.6] years; 194 [61%] female). Longitudinal increases in WMH volume were greater in individuals with CMBs compared with those without (DIAN: t = 3.2 [P = .001]; ADNI: t = 2.7 [P = .008]), associated with longitudinal decreases in gray matter volume (DIAN: t = −3.1 [P = .002]; ADNI: t = −5.6 [P &amp;lt; .001]; HABS: t = −2.2 [P = .03]), greater in older individuals (DIAN: t = 6.8 [P &amp;lt; .001]; ADNI: t = 9.1 [P &amp;lt; .001]; HABS: t = 5.4 [P &amp;lt; .001]), and not associated with systemic vascular risk (DIAN: t = 0.7 [P = .40]; ADNI: t = 0.6 [P = .50]; HABS: t = 1.8 [P = .06]) in individuals with ADAD and LOAD after accounting for age, gray matter volume, CMB presence, and amyloid burden. In older adults without CMBs at baseline, greater WMH volume was associated with CMB development during longitudinal follow-up (Cox proportional hazards regression model hazard ratio, 2.63; 95% CI, 1.72-4.03; P &amp;lt; .001).Conclusions and RelevanceThe findings suggest that increased WMH volume in AD is associated with neurodegeneration and parenchymal and vessel amyloidosis but not with elevated systemic vascular risk. Additionally, increased WMH volume may represent an early sign of vessel amyloidosis preceding the emergence of CMBs.

INTRODUCTION The cerebral cortex underlies our complex cognitive capabilities. Variations in human cortical surface area and thickness are associated with neurological, psychological, and behavioral traits and can be measured in vivo by magnetic resonance imaging (MRI). Studies in model organisms have identified genes that influence cortical structure, but little is known about common genetic variants that affect human cortical structure. RATIONALE To identify genetic variants associated with human cortical structure at both global and regional levels, we conducted a genome-wide association meta-analysis of brain MRI data from 51,665 individuals across 60 cohorts. We analyzed the surface area and average thickness of the whole cortex and 34 cortical regions with known functional specializations. RESULTS We identified 369 nominally genome-wide significant loci ( P < 5 × 10 −8 ) associated with cortical structure in a discovery sample of 33,992 participants of European ancestry. Of the 360 loci for which replication data were available, 241 loci influencing surface area and 66 influencing thickness remained significant after replication, with 237 loci passing multiple testing correction ( P < 8.3 × 10 −10 ; 187 influencing surface area and 50 influencing thickness). Common genetic variants explained 34% (SE = 3%) of the variation in total surface area and 26% (SE = 2%) in average thickness; surface area and thickness showed a negative genetic correlation ( r G = −0.32, SE = 0.05, P = 6.5 × 10 −12 ), which suggests that genetic influences have opposing effects on surface area and thickness. Bioinformatic analyses showed that total surface area is influenced by genetic variants that alter gene regulatory activity in neural progenitor cells during fetal development. By contrast, average thickness is influenced by active regulatory elements in adult brain samples, which may reflect processes that occur after mid-fetal development, such as myelination, branching, or pruning. When considered together, these results support the radial unit hypothesis that different developmental mechanisms promote surface area expansion and increases in thickness. To identify specific genetic influences on individual cortical regions, we controlled for global measures (total surface area or average thickness) in the regional analyses. After multiple testing correction, we identified 175 loci that influence regional surface area and 46 that influence regional thickness. Loci that affect regional surface area cluster near genes involved in the Wnt signaling pathway, which is known to influence areal identity. We observed significant positive genetic correlations and evidence of bidirectional causation of total surface area with both general cognitive functioning and educational attainment. We found additional positive genetic correlations between total surface area and Parkinson’s disease but did not find evidence of causation. Negative genetic correlations were evident between total surface area and insomnia, attention deficit hyperactivity disorder, depressive symptoms, major depressive disorder, and neuroticism. CONCLUSION This large-scale collaborative work enhances our understanding of the genetic architecture of the human cerebral cortex and its regional patterning. The highly polygenic architecture of the cortex suggests that distinct genes are involved in the development of specific cortical areas. Moreover, we find evidence that brain structure is a key phenotype along the causal pathway that leads from genetic variation to differences in general cognitive function. Identifying genetic influences on human cortical structure. ( A ) Measurement of cortical surface area and thickness from MRI. ( B ) Genomic locations of common genetic variants that influence global and regional cortical structure. ( C ) Our results support the radial unit hypothesis that the expansion of cortical surface area is driven by proliferating neural progenitor cells. ( D ) Cortical surface area shows genetic correlation with psychiatric and cognitive traits. Error bars indicate SE. IMAGE CREDITS: (A) K. COURTNEY; (C) M. R. GLASS