Quantifying dilated perivascular spaces in children with sickle cell disease.

Sickle cell disease (SCD)-related neurological effects are particularly devastating. Dilated perivascular spaces (dPVS) are a well-described component of cerebral small vessel disease in older adults without SCD. However, the burden and association of dPVS with neurological complications in children with SCD have not been described. In this study, we used the international consensus criteria to quantify dPVS in the centrum semiovale and basal ganglia in T2-weighted magnetic resonance images (MRI) of children with SCD who were randomized as part of the Silent Cerebral Infarct Transfusion (SIT) trial. We examined the relationship between global and/or regional dPVS burden and presence or area of silent cerebral infarctions, hematological measures, demographic variables, and full-scale intelligence quotient (FSIQ) scores. The study included 156 SIT trial participants who had pre-randomization and study exit MRI. Their median age was 9.6 (5-15) years, 39% were female, and 94 (60%) participants had a high dPVS burden. Participants randomized to the blood transfusion arm and who had a high dPVS burden at baseline had a moderate decline in dPVS score over 36 months compared to no change in the observation group. On multivariable logistic regression, intelligence quotient was not associated with dPVS burden. Children with SCD included in the SIT trial have a high burden of dPVS compared to children without SCD. However, dPVS do not appear to have the same pathophysiology of silent cerebral infarcts. Further study is needed to determine both their etiology and clinical relevance.

Risk factors in developing amyloid related imaging abnormalities (ARIA) and clinical implications.

Alzheimer's disease (AD) affects over 6 million people over the age of 65. The advent of new anti-amyloid monoclonal antibodies as treatment for early Alzheimer's disease these immunotherapeutics may slow disease progression but also pose significant risks. Amyloid related imaging abnormalities (ARIA) identified on MRI following administration of these new monoclonal antibodies can cause both brain edema (ARIA-E) and hemorrhage (ARIA-H). While most ARIA is asymptomatic, some patients can develop headache, confusion, nausea, dizziness, seizures and in rare cases death. By analyzing lecanemab, aducanumab, gantenerumab, donanemab, and bapineuzumab clinical trials; risk factors for developing ARIA can be identified to mitigate some of the ARIA risk. Risk factors for developing ARIA-E are a positive Apoε4 carrier status and prior multiple cerebral microhemorrhages. Risk factors for ARIA-H are age, antithrombotic use, and history of prior strokes. With lecanemab, ARIA-E and ARIA-H were seen at lower rates 12 and 17%, respectively, compared to aducanumab (ARIA-E 35% and ARIA-H 19%) in treated patients. ARIA risk factors have impacted inclusion and exclusion criteria, determining who can receive lecanemab. In some clinics, almost 90% of Alzheimer's patients are excluded from receiving these new anti-amyloid therapeutics. This review aims to discuss risk factors of ARIA and highlight important areas for further research. With more anti-amyloid monoclonal antibodies approved by the Food and Drug Administration, considering patient risk factors for developing ARIA is important to identify to minimize patient's risk while receiving these new therapies.

History of obstructive sleep apnea associated with incident cognitive impairment in white but not black individuals in a US national cohort study.

BACKGROUND: We sought to determine if risk for obstructive sleep apnea (OSA), a history of OSA, and/or treatment of OSA has a different association with incident cognitive impairment or cognitive decline in Black individuals and White individuals. METHODS: To determine whether the risk for OSA, a history of OSA, and/or treatment of OSA has a different association with incident cognitive impairment or cognitive decline in Black individuals and White individuals; data from the REasons for Geographic and Racial Differences in Stroke (REGARDS) was used. Participants that completed the sleep questionnaire module, had baseline cognitive assessment, and at least one cognitive assessment during follow-up were included. Risk of OSA was determined based on Berlin Sleep Questionnaire. History of sleep apnea was determined based on structured interview questions. Optimally treated OSA was defined as treated sleep apnea as at least 4 h of continuous positive airway pressure use per night for ≥5 nights per week. RESULTS: In 19,017 participants stratified by race, White participants with history of OSA were 1.62 times more likely to have incident cognitive impairment compared to White participants without history of OSA after adjusting for demographic characteristics, history, and lifestyle factors (OR = 1.62, 95% CI = 1.05-2.50, p-value = 0.03). This relationship was not seen in Black participants (OR = 0.92, 95% CI = 0.60-1.43, p-value = 0.72). DISCUSSION: A previous diagnosis of OSA is associated with incident cognitive impairment in White Americans but not Black Americans. Further investigations are required to determine the mechanism for this difference.

Methods of a Study to Assess the Contribution of Cerebral Small Vessel Disease and Dementia Risk Alleles to Racial Disparities in Vascular Cognitive Impairment and Dementia.

Background Non-Hispanic Black adults have a higher proportion of vascular cognitive impairment and Alzheimer's disease and related dementias compared with non-Hispanic White adults that may be due to differences in the burden of cerebral small vessel disease and risk alleles for Alzheimer's disease and related dementias. We describe here the methods of an ancillary study to the REGARDS (Reason for Geographic and and Racial Difference in Stroke) study, which will examine the role of magnetic resonance imaging markers of cerebral small vessel disease and vascular as well as genetic risk factors for Alzheimer's disease and related dementias in racial disparity in the prevalence and trajectory of vascular cognitive impairment and dementia in non-Hispanic White and non-Hispanic Black participants. Methods In participants with no prior history of stroke who had an incident stroke or transient ischemic attack after enrollment in the study, magnetic resonance imaging scans will be evaluated using the Standards for Reporting Vascular Changes on Neuroimaging international consensus criteria and automated analysis pipelines for quantification of cerebral small vessel disease. Participants will be genotyped for APOE ε4 and TREM2 risk alleles for Alzheimer's disease and related dementias. The 6-item screener will define global cognitive function and be the primary cognitive outcome. Conclusions With at least 426 non-Hispanic Black and 463 non-Hispanic White participants who have at least 2 prior and 2 poststroke or transient ischemic attack cognitive assessments, we will have at least 80% power to detect a minimum effect size of 0.09 SD change in Z score, with correction for as many as 20 tests (ie, at P<0.0025, after adjusting for up to 20 covariates) for cognitive decline.

Parkinson's disease diagnosis codes are insufficiently accurate for electronic health record research and differ by race.

BACKGROUND: There are no evidence-based guidelines for data cleaning of electronic health record (EHR) databases in Parkinson's disease (PD). Previous filtering criteria have primarily used the 9th International Statistical Classification of Diseases and Related Health Problems (ICD) with variable accuracy for true PD cases. Prior studies have not excluded atypical or drug-induced parkinsonism, and little is known about differences in accuracy by race. OBJECTIVE: To determine if excluding parkinsonism diagnoses improves accuracy of ICD-9 and -10 PD diagnosis codes. METHODS: We included ≥2 instances of an ICD-9 and/or -10 code for PD. We removed any records with at least one code indicating atypical or drug-induced parkinsonism first in all races, and then in Non-Hispanic White and Black patients. We manually reviewed 100 randomly selected charts per group before and after filtering, and performed a test of proportion (null hypothesis 0.5) for confirmed PD. RESULTS: 5633 records had ≥2 instances of a PD code. 2833 remained after filtering. The rate of true PD cases was low before and after filtering to remove parkinsonism codes (0.55 vs. 0.51, p = 0.84). Accuracy was lowest in Black patients before filtering (0.48, p = 0.69), but filtering had a greater (though modest) impact on accuracy (0.68, p < 0.001). CONCLUSIONS: There was inadequate accuracy of PD diagnosis codes in the largest study of ICD-9 and -10 codes. Accuracy was lowest in Black patients but improved the most with removing other parkinsonism codes. This highlights the limitations of using current real-world EHR data in PD research and need for further study.

Radiogenomics of C9orf72 Expansion Carriers Reveals Global Transposable Element Derepression and Enables Prediction of Thalamic Atrophy and Clinical Impairment.

Hexanucleotide repeat expansion (HRE) within C9orf72 is the most common genetic cause of frontotemporal dementia (FTD). Thalamic atrophy occurs in both sporadic and familial FTD but is thought to distinctly affect HRE carriers. Separately, emerging evidence suggests widespread derepression of transposable elements (TEs) in the brain in several neurodegenerative diseases, including C9orf72 HRE-mediated FTD (C9-FTD). Whether TE activation can be measured in peripheral blood and how the reduction in peripheral C9orf72 expression observed in HRE carriers relates to atrophy and clinical impairment remain unknown. We used FreeSurfer software to assess the effects of C9orf72 HRE and clinical diagnosis (n = 78 individuals, male and female) on atrophy of thalamic nuclei. We also generated a novel, human, whole-blood RNA-sequencing dataset to determine the relationships among peripheral C9orf72 expression, TE activation, thalamic atrophy, and clinical severity (n = 114 individuals, male and female). We confirmed global thalamic atrophy and reduced C9orf72 expression in HRE carriers. Moreover, we identified disproportionate atrophy of the right mediodorsal lateral nucleus in HRE carriers and showed that C9orf72 expression associated with clinical severity, independent of thalamic atrophy. Strikingly, we found global peripheral activation of TEs, including the human endogenous LINE-1 element L1HS L1HS levels were associated with atrophy of multiple pulvinar nuclei, a thalamic region implicated in C9-FTD. Integration of peripheral transcriptomic and neuroimaging data from human HRE carriers revealed atrophy of specific thalamic nuclei, demonstrated that C9orf72 levels relate to clinical severity, and identified marked derepression of TEs, including L1HS, which predicted atrophy of FTD-relevant thalamic nuclei.SIGNIFICANCE STATEMENT Pathogenic repeat expansion in C9orf72 is the most frequent genetic cause of FTD and amyotrophic lateral sclerosis (ALS; C9-FTD/ALS). The clinical, neuroimaging, and pathologic features of C9-FTD/ALS are well characterized, whereas the intersections of transcriptomic dysregulation and brain structure remain largely unexplored. Herein, we used a novel radiogenomic approach to examine the relationship between peripheral blood transcriptomics and thalamic atrophy, a neuroimaging feature disproportionately impacted in C9-FTD/ALS. We confirmed reduction of C9orf72 in blood and found broad dysregulation of transposable elements-genetic elements typically repressed in the human genome-in symptomatic C9orf72 expansion carriers, which associated with atrophy of thalamic nuclei relevant to FTD. C9orf72 expression was also associated with clinical severity, suggesting that peripheral C9orf72 levels capture disease-relevant information.

Frontotemporal degeneration genetic risk loci and transcription regulation as a possible mechanistic link to disease risk.

The etiology of Frontotemporal Degeneration (FTD) is not well understood. Genetic studies have established common genetic variants (GVs) that are associated with increased FTD risk. We review previous genome wide association studies (GWAS) of FTD and nominate specific transcriptional regulators as potential key players in the etiology of this disease. A list of GVs associated with FTD was compiled from published GWAS. The regulatory element locus intersection (RELI) tool was used to calculate the enrichment of the overlap between disease risk GVs and the genomic coordinates of data from a collection of >10,000 chromatin immunoprecipitation (ChIP-seq) experiments. After linkage disequilibrium expansion of the previously reported tag associated GVs, we identified 914 GV at 47 independent risk loci. Using the RELI algorithm, we identified several transcriptional regulators with enriched binding at FTD risk loci (0.05 < corrected P value <1.18 × 10-27), including Tripartite motif-containing 28 (TRIM28) and Chromodomain-Helicase DNA-binding 1 (CHD1) which have previously observed roles in FTD. FTD is a complex disease, and immune dysregulation has been previously implicated as a potential underlying cause. This assessment of established FTD risk loci and analysis of possible function implicates transcriptional dysregulation, and specifically particular transcriptional regulators with known roles in the immune response as important in the genetic etiology of FTD.

MicroRNA expression within neuronal-derived small extracellular vesicles in frontotemporal degeneration.

MicroRNAs (miRNAs) are small non-coding RNA that are powerful regulators of gene expression and can affect the expression of hundreds of genes. miRNAs can be packed in small extracellular vesicles (SEV) and released into the extracellular space by neurons and microglia to act locally as well as pass through the blood-brain barrier and act systemically. We sought to understand the differences in neuronal SEV miRNA expression between frontotemporal dementia (FTD), Alzheimer's disease (AD), and healthy aging. Plasma was obtained from FTD, AD, and healthy aging participants that were matched based on age, sex, and race/ethnicity. Additionally, a subset of participants also provided paired cerebrospinal fluid samples to compare neuronal SEV miRNAs in plasma and cerebrospinal fluid. Neuronal SEV were isolated using differential ultracentrifugation and antibody conjugated Dynabeads® for the neuronal surface marker, L1CAM. RNA sequencing was performed. 12 FTD, 11 with AD, and 10 healthy aging participants were enrolled in the study. In FTD, SEV miRNA-181c was downregulated compared to healthy controls. In AD, miRNA-122 and miRNA-3591 were downregulated compared to those in healthy controls and FTD. Using an FDR <0.2, only miRNA-21-5p was found to have increased expression in the cerebrospinal fluid compared to plasma in a group of AD and FTD participants. SEV miRNA-181c is significantly downregulated in FTD compared to healthy controls and may mediate its effects through microglial-directed neuroinflammation and interaction with TAR DNA-binding protein 43 (TDP-43) based on pathway analysis. Additionally, the FOXO and Hippo pathways may be important mediators of FTD, based on pathway analysis. Lastly, because only one SEV miRNA was differentially expressed between the plasma and cerebrospinal fluid in paired samples, plasma represents an appropriate biofluid for studying neuronal SEV miRNA.

Alzheimer's disease related single nucleotide polymorphisms and correlation with intracerebral hemorrhage incidence.

Apolipoprotein E alleles have been associated with both Alzheimer's disease (AD) and intracerebral hemorrhage (ICH). In addition, ICH is associated with a markedly high risk of subsequent dementia compared to other subtypes of stroke. We sought to evaluate if other genetic markers for AD were also associated with ICH. We examined whether published AD risk single nucleotide polymorphisms (SNPs) and haplotypes were associated with ICH utilizing genome-wide association study data from 2 independent studies (genetic and environmental risk factors for hemorrhagic stroke [GERFHS] study and genetics of cerebral hemorrhage with anticoagulation [GOCHA]). Analyses included evaluation by location of ICH. GERFHS and GOCHA cohorts contained 745 ICH cases and 536 controls for analysis. The strongest association was on 1q32 near Complement receptor type 1 (CR1), where rs6701713 was associated with all ICH (P = .0074, odds ratio [OR] = 2.07) and lobar ICH (P = .0073, OR = 2.80). The 51 most significant 2-SNP haplotypes associated with lobar ICH were identified within the Clusterin (CLU) gene. We identified that variation within CR1 and CLU, previously identified risk factors for AD, and are associated with an increased risk for ICH driven primarily by lobar ICH. Previous work implicated CR1 and CLU in cerebral amyloid clearance, the innate immune system, and cellular stress response.

Effect of Blood Transfusion on Cerebral Hemodynamics and Vascular Topology Described by Computational Fluid Dynamics in Sickle Cell Disease Patients.

The main objective of this study was to demonstrate that computational fluid dynamics (CFD) modeling can be used to study the contribution of covert and overt vascular architecture to the risk for cerebrovascular disease in sickle cell disease (SCD) and to determine the mechanisms of response to therapy such as chronic red blood cell (cRBC) transfusions. We analyzed baseline (screening), pre-randomization and study exit magnetic resonance angiogram (MRA) images from 10 (5 each from the transfusion and observation arms) pediatric sickle SCD participants in the silent cerebral infarct transfusion (SIT) trial using CFD modeling. We reconstructed the intracranial portion of the internal carotid artery and branches and extracted the geometry using 3D Slicer. We cut specific portions of the large intracranial artery to include segments of the internal carotid, middle, anterior, and posterior cerebral arteries such that the vessel segment analyzed extended from the intracranial beginning of the internal carotid artery up to immediately after (~0.25 inches) the middle cerebral artery branching point. Cut models were imported into Ansys 2021R2/2022R1 and laminar and time-dependent flow simulation was performed. Change in time averaged mean velocity, wall shear stress, and vessel tortuosity were compared between the observation and cRBC arms. We did not observe a correlation between time averaged mean velocity (TAMV) and mean transcranial Doppler (TCD) velocity at study entry. There was also no difference in change in time average mean velocity, wall shear stress (WSS), and vessel tortuosity between the observation and cRBC transfusion arms. WSS and TAMV were abnormal for 2 (developed TIA) out of the 3 participants (one participant had silent cerebral infarctions) that developed neurovascular outcomes. CFD approaches allow for the evaluation of vascular topology and hemodynamics in SCD using MRA images. In this proof of principle study, we show that CFD could be a useful tool and we intend to carry out future studies with a larger sample to enable more robust conclusions.

Differences in peripheral immune system gene expression in frontotemporal degeneration.

ABSTRACT: The peripheral immune system has a key pathophysiologic role in Frontotemporal degeneration (FTD). We sought a comprehensive transcriptome-wide evaluation of gene expression alterations unique to the peripheral immune system in FTD compared to healthy controls and amyotrophic lateral sclerosis.Nineteen subjects with FTD with 19 matched healthy controls and 9 subjects with amyotrophic lateral sclerosis underwent isolation of peripheral blood mononuclear cells (PBMCs) which then underwent bulk ribonucleic acid sequencing.There was increased expression in genes associated with CD19+ B-cells, CD4+ T-cells, and CD8+ T-cells in FTD participants compared to healthy controls. In contrast, there was decreased expression in CD33+ myeloid cells, CD14+ monocytes, BDCA4+ dendritic cells, and CD56+ natural killer cells in FTD and healthy controls. Additionally, there was decreased expression is seen in associated with 2 molecular processes: autophagy with phagosomes and lysosomes, and protein processing/export. Significantly downregulated in PBMCs of FTD subjects were genes involved in antigen processing and presentation as well as lysosomal lumen formation compared to healthy control PBMCs.Our findings that the immune signature based on gene expression in PBMCs of FTD participants favors adaptive immune cells compared to innate immune cells. And decreased expression in genes associated with phagosomes and lysosomes in PBMCs of FTD participants compared to healthy controls.

Impact of Preexisting Cognitive Impairment and Race/Ethnicity on Functional Outcomes Following Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: In intracerebral hemorrhage (ICH), preexisting cognitive impairment has been identified as a risk factor for increased mortality and morbidity. However, previous studies examined predominantly White populations; therefore, the prevalence and effect of preICH cognitive impairment has not been studied in a multiethnic cohort. This limits the generalizability of previous findings. We sought to investigate the role of preexisting cognitive impairment in a multiethnic population on short-term mortality and functional outcomes after ICH. METHODS: Patients with ICH were prospectively enrolled as cases for the GERFHS III (Genetic and Environmental Risk Factors for Hemorrhagic Stroke) Study and the Ethnic/Racial Variations of ICH (ERICH) Study. Cognitive impairment before ICH was defined as positive history of dementia or treatment with donepezil, galantamine, memantine, or rivastigmine on chart abstraction or baseline interview. Specific outcomes-modified Rankin Scale score at 3 months (0-2 versus ≥3), Barthel Index score (<100 versus 100) at 3 months, and withdrawal of care-were analyzed using multivariable logistic regression. Propensity score matching and analysis was done because of imbalances between cognitively impaired and cognitively intact groups. RESULTS: Of the 3537 cases of ICH, 304 patients had cognitive impairment predating ICH. Cognitively impaired subjects were more likely to experience withdrawal of care during hospitalization, and for survivors, greater disability (modified Rankin Scale score of ≥3) and lower Barthel scores after ICH. After propensity score matching, preexisting cognitive impairment was associated with a lower modified Rankin Scale at 3 months in the White, Black, and Hispanic subgroups. CONCLUSIONS: Preexisting cognitive impairment was associated with loss of independence 3-month post-ICH, when matching for risk factors of cognitive impairment, in the White, Black, and Hispanic subgroups. This suggests that preexisting cognitive impairment has a negative effect in obtaining functional independence following ICH, irrespective of race/ethnicity.

White Matter Lesion Severity is Associated with Intraventricular Hemorrhage in Spontaneous Intracerebral Hemorrhage.

BACKGROUND: Intraventricular hemorrhage (IVH) and white matter lesion (WML) severity are associated with higher rates of death and disability in intracerebral hemorrhage (ICH). A prior report identified an increased risk of IVH with greater WML burden but did not control for location of ICH. We sought to determine whether a higher degree of WML is associated with a higher risk of IVH after controlling for ICH location. METHODS: Utilizing the patient population from 2 large ICH studies; the Genetic and Environmental Risk Factors for Hemorrhagic Stroke (GERFHS III) Study and the Ethnic/Racial Variations of Intracerebral Hemorrhage study, we graded WML using the Van Swieten Scale (0-1 for mild, 2 for moderate, and 3-4 for severe WML) and presence or absence of IVH in baseline CT scans. We used multivariable regression models to adjust for relevant covariates. RESULTS: Among 3023 ICH patients, 1260 (41.7%) had presence of IVH. In patients with IVH, the proportion of severe WML (28.6%) was higher compared with patients without IVH (21.8%) (P < .0001). Multivariable analysis demonstrated that moderate-severe WML, deep ICH, and increasing ICH volume were independently associated with presence of IVH. We found an increased risk of IVH with moderate-severe WML (OR = 1.38; 95%Cl 1.03-1.86, P = .0328) in the subset of lobar hemorrhages. CONCLUSIONS: Moderate to severe WML is a risk for IVH. Even in lobar ICH hemorrhages, severe WML leads to an independent increased risk for ventricular rupture.

Racial/ethnic variation of APOE alleles for lobar intracerebral hemorrhage.

OBJECTIVE: APOE ε2 and ε4 alleles have been associated with lobar intracerebral hemorrhage (ICH) in predominately white populations; we sought to evaluate whether this held true among black and Hispanic populations. METHODS: The Ethnic/Racial Variations of Intracerebral Hemorrhage study is a prospective, multicenter case-control study of ICH among white, black, and Hispanic participants. Controls were recruited to match cases based on age, ethnicity/race, sex, and geographic location. APOE genotyping and ICH location was determined blinded to clinical data. RESULTS: There were 907 cases of lobar ICH and 2,660 controls with APOE results. Both APOE ε2 (odds ratio [OR] 1.5, 95% confidence interval [CI] 1.1-2.0, p = 0.01) and APOE ε4 (OR 2.0, 95% CI 1.5-2.6, p < 1 × 10-4) were associated with lobar ICH among white participants. Among black participants, neither APOE ε2 (OR 1.0, 95% CI 0.7-1.5, p = 0.97) nor APOE ε4 (OR 1.0, 95% CI 0.7-1.4, p = 0.90) were independent risk factors for lobar ICH. Similarly, among Hispanic participants, neither APOE ε2 (OR 1.0, 95% CI 0.6-1.8, p = 0.89) nor APOE ε4 (OR 1.2, 95% CI 0.8-1.7, p = 0.36) were associated with lobar ICH. Hypertension was a significant risk factor for lobar ICH in all 3 racial/ethnic groups. CONCLUSION: In contrast to Caucasian patients, in which amyloid risk factors predominate in lobar ICH, we found that hypertension was the predominant risk factor for lobar ICH. While APOE alleles are a risk factor for lobar ICH in white patients, they appear to have a much lower effect in lobar ICH in African American and Hispanic American populations. This suggests APOE ε2 and APOE ε4 do not affect lobar ICH risk homogeneously across ethnic populations. In addition, hypertension has a prominent role in lobar ICH risk, particularly among minorities.

Orthostatic hypotension in Parkinson disease: Impact on health care utilization.

INTRODUCTION: Orthostatic hypotension (OH) represents a frequent yet overlooked source of disability in Parkinson disease (PD). In particular, its impact on health care utilization has been insufficiently examined. We sought to determine the differential health care utilization in PD patients with (PDOH+) and without OH (PDOH-). METHODS: We quantified the emergency room (ER) visits, hospitalizations, outpatient clinic evaluations, phone calls, and e-mails from PD patients on whom supine and orthostatic blood pressure (BP) measurements were obtained during routine clinical practice between June 2013 and July 2016. Comparative costs between PDOH+ and PDOH- were adjusted for age, disease duration, motor severity, levodopa equivalent daily dose, and Montreal Cognitive Assessment. RESULTS: From a total of 317 PD patients, 29.3% were classified as PDOH+ (n = 93) and 70.6% as PDOH- (n = 224) over 30.2 ± 11.0 months, in which there were 247 hospitalizations, 170 ER visits, 2386 outpatient evaluations, and 4747 telephone calls/e-mails. After-adjusting for relevant covariates, PDOH+ was associated with more hospitalization days (+285%; p = 0.041), ER visits (+152%; p = 0.045), and telephone calls/e-mails than PDOH- (+142%; p = 0.009). The overall health care-related cost in PDOH+ was 2.5-fold higher than for PDOH- ($25,205 ± $6546 vs. $9831 ± $4167/person/year; p = 0.037). CONCLUSION: OH increases health care utilization in PD independently from age, disease duration, motor severity, dopaminergic treatment, and cognitive function.

Diagnosing the frontal variant of Alzheimer's disease: a clinician's yellow brick road.

BACKGROUND: Disruption of the frontal lobes and its associated networks are a common consequence of neurodegenerative disorders. Given the wide range of cognitive, behavioral and motor processes in which the frontal lobes are involved, there can be a great variety of manifestations depending on the pathology distribution. The most common are the behavioral variant of frontotemporal dementia (bvFTD) and the frontal variant of Alzheimer's disease (fvAD), which are particularly challenging to disentangle. Recognizing fvAD from bvFTD-related pathologies is a diagnostic challenge and a critical need in the management and counseling of these patients. CASE PRESENTATION: Here we present three pathology-proven cases of Alzheimer's disease initially misdiagnosed as bvFTD and discuss the distinctive or less overlapping historical, examination, and laboratory findings of fvAD and bvFTD, deriving analogies for mnemonic endurance from the Wizard of Oz worldview. CONCLUSION: The Yellow Brick Road to diagnosing these disorders may be served by the metaphor of fvAD as the irritable, paranoid, and tremulous Scarecrow and bvFTD the heartless, ritualistic, and rigid Tin Man. An Oz-inspired creative license may help the clinician recognize the differential disease progression, caregiver burden, and treatment response of fvAD compared with bvFTD.