Predominant right temporal lobe atrophy: Clinical, neuropsychological and structural differences based on amyloid status.

BACKGROUND: Predominant right temporal atrophy is a radiological sign usually associated with frontotemporal dementia but this sign can also be present in Alzheimer's disease. Given the overlap of clinical symptoms between the two conditions, it is important to know which characteristics allow them to be differentiated. OBJECTIVES: To compare clinical, neuropsychological and structural magnetic resonance imaging (MRI) data of subjects with prominent right anterior temporal atrophy, depending on the status of amyloid biomarkers. METHODS: Among patients followed in the dementia center of Ospedale Maggiore Policlinico, subjects with right anterior temporal atrophy, defined as grade 3 or 4 on the corresponding visual rating scale, were identified. Only subjects with both an MRI scan and amyloid status available were considered. For selected subjects, data were extracted from clinical and neuropsychological records at initial presentation and at last available follow-up. Two raters applied a protocol of eight visual rating scales to compare brain atrophy and white matter hyperintensities. RESULTS: Of 497 subjects, 17 fulfilled the inclusion criteria: 7 amyloid-positive and 10 amyloid-negative. At initial presentation, executive dysfunction and topographical disorientation were more common in amyloid-positive patients. At follow-up, behavioral symptoms, such as social awkwardness and compulsive attitude, were more frequent in the amyloid-negative patients. Amyloid-positive patients presented an overall worse neuropsychological performance, especially in the language and visuospatial domain, and had higher scores on the right anterior cingulate visual rating scale. CONCLUSION: Patients with predominant right temporal atrophy showed clinical, neuropsychological and radiological differences, depending on the status of amyloid biomarkers.

Quantitative susceptibility mapping of the normal-appearing white matter as a potential new marker of disability progression in multiple sclerosis.

OBJECTIVES: To investigate the normal-appearing white matter (NAWM) susceptibility in a cohort of newly diagnosed multiple sclerosis (MS) patients and to evaluate possible correlations between NAWM susceptibility and disability progression. METHODS: Fifty-nine patients with a diagnosis of MS (n = 53) or clinically isolated syndrome (CIS) (n = 6) were recruited and followed up. All participants underwent neurological examination, blood sampling for serum neurofilament light chain (sNfL) level assessment, lumbar puncture for the quantification of cerebrospinal fluid (CSF) ß-amyloid1-42 (Aß) levels, and brain MRI. T2-weighted scans were used to quantify white matter (WM) lesion loads. For each scan, we derived the NAWM volume fraction and the WM lesion volume fraction. Quantitative susceptibility mapping (QSM) of the NAWM was calculated using the susceptibility tensor imaging (STI) suite. Susceptibility maps were computed with the STAR algorithm. RESULTS: Primary progressive patients (n = 9) showed a higher mean susceptibility value in the NAWM than relapsing-remitting (n = 44) and CIS (n = 6) (p = 0.01 and p = 0.02). Patients with a higher susceptibility in the NAWM showed increased sNfL concentration (ρ = 0.38, p = 0.004) and lower CSF Aß levels (ρ = -0.34, p = 0.009). Mean NAWM susceptibility turned out to be a predictor of the expanded disability status scale (EDSS) worsening at follow-up (ß = 0.41, t = 2.66, p = 0.01) and of the MS severity scale (MSSS) (ß = 0.38, t = 2.43, p = 0.019). CONCLUSIONS: QSM in the NAWM seems to predict the EDSS increment over time. This finding might provide evidence on the role of QSM in identifying patients with an increased risk of early disability progression. KEY POINTS: • NAWM-QSM is higher in PPMS patients than in RRMS. • NAWM-QSM seems to be a predictor of EDSS worsening over time. • Patients with higher NAWM-QSM show increased sNfL concentration and lower CSF Aß levels.

Utility of visual rating scales in primary progressive aphasia.

INTRODUCTION: Differential diagnosis among subjects with Primary Progressive Aphasia (PPA) can be challenging. Structural MRI can support the clinical profile. Visual rating scales are a simple and reliable tool to assess brain atrophy in the clinical setting. The aims of the study were to establish to what extent the visual rating scales could be useful in the differential diagnosis of PPA, to compare the clinical diagnostic impressions derived from routine MRI interpretations with those obtained using the visual rating scale and to correlate results of the scales in a voxel-based morphometry (VBM) analysis. METHOD: Patients diagnosed with primary progressive aphasia (PPA) according to current criteria from two centers-Ospedale Maggiore Policlinico of Milan and Hospital Clínic de Barcelona-were included in the study. Two blinded clinicians evaluated the subjects MRIs for cortical atrophy and white matter hyperintensities using two protocols: routine readings and the visual rating scale. The diagnostic accuracy between patients and controls and within PPA subgroups were compared between the two protocols. RESULTS: One hundred fifty Subjects were studied. All the scales showed a good to excellent intra and inter-rater agreement. The left anterior temporal scale could differentiate between semantic PPA and all other variants. The rater impression after the protocol can increase the accuracy just for the logopenic PPA. In the VBM analysis, the scores of visual rating scales correlate with the corresponding area of brain atrophy. CONCLUSION: The Left anterior temporal rating scale can distinguish semantic PPA from other variants. The rater impression after structured view improved the diagnostic accuracy of logopenic PPA compared to normal readings. The unstructured view of the MRI was reliable for identifying semantic PPA and controls. Neither the structured nor the unstructured view could identify the nonfluent and undetermined variants.

Association between enlarged perivascular spaces and cerebrospinal fluid aquaporin-4 and tau levels: report from a memory clinic.

Background: Perivascular spaces (PVS) are fluid-filled compartments that dilate in response to many different conditions. A high burden of enlarged PVS (EPVS) in the centrum semiovale (CSO) has been linked to neurodegeneration. Moreover, an increase in cerebrospinal fluid (CSF) levels of aquaporin-4 (AQP4), a water channel expressed on PVS-bounding astrocytes, has been described in patients with neurodegenerative dementia. Our aim was to investigate the relationship between neurodegenerative diseases and two putative glymphatic system biomarkers: AQP4 and EPVS. Methods: We included 70 individuals, 54 patients with neurodegenerative diseases and 16 subjects with non-degenerative conditions. EPVS were visually quantified on MRI-scans applying Paradise's scale. All subjects underwent lumbar puncture for the measurement of AQP4 levels in the cerebrospinal fluid (CSF). CSF levels of amyloid-ß-1-42, phosphorylated and total tau (tTau) were also measured. Linear regression analyses were adjusted for age, sex, education and disease duration, after excluding outliers. Results: Cerebrospinal fluid (CSF)-AQP4 levels were independent predictors of total (ß = 0.28, standard error [SE] = 0.08, p = 0.001), basal ganglia (ß = 0.20, SE = 0.08, p = 0.009) and centrum semiovale EPVS (ß = 0.37, SE = 0.12, p = 0.003). tTau levels predicted CSO-EPVS (ß = 0.30, SE = 0.15, p = 0.046). Moreover, increased levels of AQP4 were strongly associated with higher levels of tTau in the CSF (ß = 0.35, SE = 0.13, p = 0.008). Conclusion: We provide evidence that CSO-EPVS and CSF-AQP4 might be clinically meaningful biomarkers of glymphatic dysfunction and associated neurodegeneration.

Klotho Gene Expression Is Decreased in Peripheral Blood Mononuclear Cells in Patients with Alzheimer's Disease and Frontotemporal Dementia.

BACKGROUND: The longevity gene Klotho (KL) was recently associated with neurodegenerative diseases including Alzheimer's disease (AD). Its role in the brain has not been completely elucidated, although evidence suggests that KL-VS heterozygosity is associated with a reduced risk of AD in Apolipoprotein E ɛ4 carriers. Conversely, no data about genetic association with frontotemporal dementia (FTD) are available so far. OBJECTIVE: To investigate the involvement of KL in AD and FTD by the determination of the genetic frequency of KL-VS variant and the expression analysis of KL gene. METHODS: A population consisting of 438 patients and 240 age-matched controls was enrolled for the study. KL-VS and APOE genotypes were assessed by allelic discrimination through a QuantStudio 12K system. KL gene expression analysis was performed in a restricted cohort of patients consisting of 43 AD patients, 41 FTD patients and 19 controls. KL gene expression was assessed in peripheral blood mononuclear cells with specific TaqMan assay. Statistical analysis was performed using GraphPad 9 Prims software. RESULTS: KL-VS frequency was comparable to the ones found in literature and no differences were found in both allelic and genotypic frequencies between patients and controls were found. Conversely, KL expression levels were significantly lower in AD and FTD patients compared with controls (mean fold regulation - 4.286 and - 6.561 versus controls in AD and FTD, respectively, p = 0.0037). CONCLUSION: This is the first study investigating KL in FTD. We showed a decreased expression of the gene in AD and FTD, independent of the genotype, suggesting a role of Klotho in common steps during neurodegeneration.

Banks of the Superior Temporal Sulcus in Alzheimer's Disease: A Pilot Quantitative Susceptibility Mapping Study.

BACKGROUND: Brain iron homeostasis is disrupted in neurodegeneration and areas of iron overload partially overlap with regions of amyloid and tau burden in Alzheimer's disease (AD). Previous studies demonstrated alterations in brain iron accumulation in AD using quantitative susceptibility mapping (QSM). OBJECTIVE: Here, we investigate brain alterations of QSM values in AD and non-AD patients as compared to healthy controls (HC) in the superior temporal sulcus and its banks (BANKSSTS), one of the top AD-affected regions. METHODS: Thirty-four patients who underwent brain MRI including a multi-echo gradient-echo sequence were subdivided into AD (n = 19) and non-AD (n = 15) groups according to their clinical profile, CSF (Aß42/40) and/or amyloid-PET status. Ten HC were also included. QSM values were extracted from left and right BANKSSTS and compared among groups. Correlation and binomial regression analyses between QSM values and CSF-AD biomarkers were conducted. RESULTS: QSM in left BANKSSTS was significantly different among groups (p = 0.003, H = 11.40), being higher in AD. QSM values in left BANKSSTS were correlated with Aß42 (rho -0.55, p = 0.005), Aß42/40 (rho -0.66, p < 0.001), pTau (rho 0.63, p < 0.001), tTau (rho 0.56, p = 0.005), tTau/Aß42 (rho 0.68, p < 0.001) and pTau/Aß42 (rho 0.71, p < 0.001). No correlations between QSM values and amyloid-PET SUVR in the left BANKSSTS were found. QSM values in left BANKSSTS showed good accuracy in discriminating AD (AUC = 0.80, CI95 % [0.66-0.93]). Higher QSM values were independent predictors of Aß42 (B = 0.63, p = 0.032), Aß42/40 (B = 0.81, p = 0.028), pTau (B = 0.96, p = 0.046), tTau (B = 0.55, p = 0.027), and tTau/Aß42 (B = 1.13, p = 0.042) positivity. CONCLUSION: Our preliminary data support the potential role of increased QSM values in the left BANKSSTS as an auxiliary imaging biomarker in AD diagnosis.

Amyloid PET imaging and dementias: potential applications in detecting and quantifying early white matter damage.

PURPOSE: Positron emission tomography (PET) with amyloid tracers (amy-PET) allows the quantification of pathological amyloid deposition in the brain tissues, including the white matter (WM). Here, we evaluate amy-PET uptake in WM lesions (WML) and in the normal-appearing WM (NAWM) of patients with Alzheimer's disease (AD) and non-AD type of dementia. METHODS: Thirty-three cognitively impaired subjects underwent brain magnetic resonance imaging (MRI), Aß1-42 (Aß) determination in the cerebrospinal fluid (CSF) and amy-PET. Twenty-three patients exhibiting concordant results in both CSF analysis and amy-PET for cortical amyloid deposition were recruited and divided into two groups, amyloid positive (A+) and negative (A-). WML quantification and brain volumes' segmentation were performed. Standardized uptake values ratios (SUVR) were calculated in the grey matter (GM), NAWM and WML on amy-PET coregistered to MRI images. RESULTS: A+ compared to A- showed a higher WML load (p = 0.049) alongside higher SUVR in all brain tissues (p < 0.01). No correlations between CSF Aß levels and WML and NAWM SUVR were found in A+, while, in A-, CSF Aß levels were directly correlated to NAWM SUVR (p = 0.04). CSF Aß concentration was the only predictor of NAWM SUVR (adj R2 = 0.91; p = 0.04) in A-. In A+ but not in A- direct correlations were identified between WM and GM SUVR (p < 0.01). CONCLUSIONS: Our data provide evidence on the role of amy-PET in the assessment of microstructural WM injury in non-AD dementia, whereas amy-PET seems less suitable to assess WM damage in AD patients due to a plausible amyloid accrual therein.

Unravelling the Association Between Amyloid-PET and Cerebrospinal Fluid Biomarkers in the Alzheimer's Disease Spectrum: Who Really Deserves an A+?

BACKGROUND: Association between cerebrospinal fluid (CSF)-amyloid-ß (Aß)42 and amyloid-PET measures is inconstant across the Alzheimer's disease (AD) spectrum. However, they are considered interchangeable, along with Aß42/40 ratio, for defining 'Alzheimer's Disease pathologic change' (A+). OBJECTIVE: Herein, we further characterized the association between amyloid-PET and CSF biomarkers and tested their agreement in a cohort of AD spectrum patients. METHODS: We included 23 patients who underwent amyloid-PET, MRI, and CSF analysis showing reduced levels of Aß42 within a 365-days interval. Thresholds used for dichotomization were: Aß42 < 640 pg/mL (Aß42+); pTau > 61 pg/mL (pTau+); and Aß42/40 < 0.069 (ADratio+). Amyloid-PET scans were visually assessed and processed by four pipelines (SPMCL, SPMAAL, FSGM, FSWC). RESULTS: Different pipelines gave highly inter-correlated standardized uptake value ratios (SUVRs) (rho = 0.93-0.99). The most significant findings were: pTau positive correlation with SPMCL SUVR (rho = 0.56, p = 0.0063) and Aß42/40 negative correlation with SPMCL and SPMAAL SUVRs (rho = -0.56, p = 0.0058; rho = -0.52, p = 0.0117 respectively). No correlations between CSF-Aß42 and global SUVRs were observed. In subregion analysis, both pTau and Aß42/40 values significantly correlated with cingulate SUVRs from any pipeline (R2 = 0.55-0.59, p < 0.0083), with the strongest associations observed for the posterior/isthmus cingulate areas. However, only associations observed for Aß42/40 ratio were still significant in linear regression models. Moreover, combining pTau with Aß42 or using Aß42/40, instead of Aß42 alone, increased concordance with amyloid-PET status from 74% to 91% based on visual reads and from 78% to 96% based on Centiloids. CONCLUSION: We confirmed that, in the AD spectrum, amyloid-PET measures show a stronger association and a better agreement with CSF-Aß42/40 and secondarily pTau rather than Aß42 levels.

Aquaporin-4 cerebrospinal fluid levels are higher in neurodegenerative dementia: looking at glymphatic system dysregulation.

Aquaporin-4 (AQP4) is a channel protein that plays a fundamental role in glymphatic system, a newly described pathway for fluid exchange in the central nervous system, as well as a central figure in a fascinating new theory for the pathophysiology of neurodegenerative diseases such as Alzheimer's disease (AD) and frontotemporal dementia (FTD). In this study, cerebrospinal fluid (CSF) concentration of AQP4, amyloid-ß, total tau and P-tau were determined in 103 CSF samples from patients affected by neurodegenerative dementias (AD and FTD) or psychiatric diseases and 21 controls. Significantly higher levels of AQP4 were found in AD and FTD patients compared to subjects not affected by neurodegenerative diseases, and a significant, positive correlation between AQP4 and total tau levels was found. This evidence may pave the way for future studies focused on the role of this channel protein in the clinical assessment of the glymphatic function and degree of neurodegeneration.

A Novel Automated Chemiluminescence Method for Detecting Cerebrospinal Fluid Amyloid-Beta 1-42 and 1-40, Total Tau and Phosphorylated-Tau: Implications for Improving Diagnostic Performance in Alzheimer's Disease.

Recently, a fully automated instrument for the detection of the Cerebrospinal Fluid (CSF) biomarker for Alzheimer's disease (AD) (low concentration of Amyloid-beta 42 (Aß42), high concentration of total tau (T-tau) and Phosphorylated-tau (P-tau181)), has been implemented, namely CLEIA. We conducted a comparative analysis between ELISA and CLEIA methods in order to evaluate the analytical precision and the diagnostic performance of the novel CLEIA system on 111 CSF samples. Results confirmed a robust correlation between ELISA and CLEIA methods, with an improvement of the accuracy with the new CLEIA methodology in the detection of the single biomarkers and in their ratio values. For Aß42 regression analysis with Passing−Bablok showed a Pearson correlation coefficient r = 0.867 (0.8120; 0.907% 95% CI p < 0.0001), T-tau analysis: r = 0.968 (0.954; 0.978% 95% CI p < 0.0001) and P-tau181: r = 0.946 (0.922; 0.962 5% 95% CI p < 0.0001). The overall ROC AUC comparison between ROC in ELISA and ROC in CLEIA confirmed a more accurate ROC AUC with the new automatic method: T-tau AUC ELISA = 0.94 (95% CI 0.89; 0.99 p < 0.0001) vs. AUC CLEIA = 0.95 (95% CI 0.89; 1.00 p < 0.0001), and P-tau181 AUC ELISA = 0.91 (95% CI 0.85; 0.98 p < 0.0001) vs. AUC CLEIA = 0.98 (95% CI 0.95; 1.00 p < 0.0001). The performance of the new CLEIA method in automation is comparable and, for tau and P-tau181, even better, as compared with standard ELISA. Hopefully, in the future, automation could be useful in clinical diagnosis and also in the context of clinical studies.

Distinct patterns of MRI lesions in MOG antibody disease and AQP4 NMOSD: a systematic review and meta-analysis.

BACKGROUND: the distinct MRI features of MOG-antibody disease (MOG-AD) and AQP4-NMOSD are still poorly defined. We performed a systematic review and meta-analysis to identify specific patterns of MRI abnormalities able to discriminate between MOG-AD and AQP4-NMOSD. METHODS: fourteen case-series (1028 patients) were included. Outcomes were MRI lesion patterns in optic nerve (ON), brain and spinal cord (SC) that were selected after a systematic literature review and analysed separately as the event rate for individual MRI lesions in MOG-AD (experimental group) and AQP4-NMOSD (control group) by using a random effect model. RESULTS: MOG-AD showed a higher number of MRI lesions than AQP4-NMOSD patients in the retrobulbar ON (OR=5.67; 95%CI=2.11-15.24; p=0.0006) with ON head swelling (OR=8.20; 95%CI=4.13-16.28; p<0.00001), corpus callosum (OR=2.30; 95%CI=1.11-4.76; p=0.02), pons (OR=2.87; 95%CI=1.45-5.67; p=0.002), and lumbar/conus SC (OR=3.47; 95%CI=1.66-7.24; p=0.0009). Conversely, lesions in the canalicular (OR=0.42; 95%CI=0.18-0.98; p=0.05) and intracranial ON (OR=0.30; 95%CI=0.11=0.84; p=0.02), area postrema (OR=0.12; 95%CI=0.02-0.61; p=0.01), medulla (OR=0.40; 95%CI=0.20-0.78; p=0.007), and cervical SC (OR=0.29; 95%CI=0.09-0.92; p=0.04) were prominent in patients with AQP4-NMOSD. Participants' age was found to be a source of heterogeneity across studies. CONCLUSION: our study provides further evidence that MOG-AD and AQP4-NMOSD have distinct MRI features that may help clinicians for an early differential diagnosis.

Detection of the SQSTM1 Mutation in a Patient with Early-Onset Hippocampal Amnestic Syndrome.

Genetics has a major role in early-onset dementia, but the correspondence between genotype and phenotype is largely tentative. We describe a 54-year-old with familial early-onset slowly-progressive episodic memory impairment with the P392L-variant in SQSTM1. The patient showed cortical atrophy and hypometabolism in the temporal lobes, but no amyloidosis biomarkers. As symptoms/neuroimaging were suggestive for Alzheimer's disease-but biomarkers were not-and considering the family-history, genetic analysis was performed, revealing the P392L-variant in SQSTM1, which encodes for sequestosome-1/p62. Increasing evidence suggests a p62 involvement in neurodegeneration and SQSTM1 mutations have been found to cause amyotrophic lateral sclerosis/frontotemporal dementia. Our report suggests that the clinical spectrum of SQSTM1 variants is wider.

Clinical features and disease course of patients with acute ischaemic stroke just before the Italian index case: Was COVID-19 already there?

Since the end of February 2020, Italy has suffered one of the most severe outbreaks of coronavirus disease 2019 (COVID-19). However, what happened just before the Italian index case has not yet been investigated. To answer this question, we evaluated the potential impact of COVID-19 on the clinical features of a cohort of neurological inpatients admitted right before the Italian index case, as compared to the same period of the previous year. Demographic, clinical, treatment and laboratory data were extracted from medical records. The data collected included all inpatients who had been admitted to the Neurology and Stroke Units of the Ospedale Maggiore Policlinico, Milan, Italy, from December 15, 2018 to February 20, 2019 and from December 15, 2019 to February 20, 2020. Of the 248 patients, 97 subjects (39.1%) were admitted for an acute cerebrovascular event: 46 in the 2018/2019 period (mean [SD] age, 72.3 [15.6] years; 22 men [47.8%]), and 51 in the 2019/2020 interval (mean [SD] age, 72.8 [12.4] years; 24 men [47.1%]). The number of cryptogenic strokes has increased during the 2019-2020 year, as compared to the previous year (30 [58.8%] vs. 18 [39.1%], p = 0.05). These patients had a longer hospitalization (mean [SD] day, 15.7 [10.5] days vs. mean [SD] day, 11.7 [7.2] days, p = 0.03) and more frequent cerebrovascular complications (9 [30.0%] vs. 2 [11.1%]), but presented a lower incidence of cardiocerebral risk factors (18 [60.0%] vs. 14 [77.8%]). Right before the Italian index case, an increase in cryptogenic strokes has occurred, possibly due to the concomitant COVID-19.

Diogenes syndrome in dementia: a case report.

BACKGROUND: Diogenes syndrome is a neurobehavioural syndrome characterised by domestic squalor, hoarding and lack of insight. It is an uncommon but high-mortality condition, often associated with dementia. AIMS: To describe the clinical features and treatment of Diogenes syndrome secondary to behavioural variant frontotemporal dementia (bvFTD). METHOD: We describe a case of bvFTD in a 77-year-old man presenting with Diogenes syndrome. RESULTS: The patient's medical and psychiatric histories were unremarkable, but in recent years he had begun packing his flat with 'art pieces'. Mental state examination revealed confabulation and more structured delusions. Neuropsychological evaluation outlined an impairment in selective attention and letter verbal fluency, but no semantic impairment, in the context of an overall preserved mental functioning. Brain magnetic resonance imaging and positron emission tomography (PET) with fluorodeoxyglucose showed mild bilateral temporo-insular atrophy and hypometabolism in the left-superior temporal gyrus respectively. An amyloid PET scan and genetic analysis covering the dementia spectrum were normal. A diagnosis of bvFTD was made. CONCLUSIONS: The clinical framing of behavioural symptoms of dementia such as hoarding poses a diagnostic challenge. This case illustrates the importance of a deeper understanding of Diogenes syndrome, leading to timelier diagnosis and effective therapeutic strategies.

Parieto-occipital sulcus widening differentiates posterior cortical atrophy from typical Alzheimer disease.

OBJECTIVES: Posterior Cortical Atrophy (PCA) is an atypical presentation of Alzheimer disease (AD) characterized by atrophy of posterior brain regions. This pattern of atrophy is usually evaluated with Koedam visual rating scale, a score developed to enable visual assessment of parietal atrophy on magnetic resonance imaging (MRI). However, Koedam scale is complex to assess and its utility in the differential diagnosis between PCA and typical AD has not been demonstrated yet. The aim of this study is therefore to spot a simple and reliable MRI element able to differentiate between PCA and typical AD using visual rating scales. METHODS: 15 patients who presented with progressive complex visual disorders and predominant occipitoparietal hypometabolism on PET-FDG were selected from our centre and compared with 30 typical AD patients and 15 healthy subjects. We used previously validated visual rating scales including Koedam scale, which we divided into three major components: posterior cingulate, precuneus and parieto-occipital. Subsequently we validated the results using the automated software Brainvisa Morphologist and Voxel Based Morphometry (VBM). RESULTS: Patients with PCA, compared to typical AD, showed higher widening of the parieto-occipital sulcus, assessed both with visual rating scales and Brainvisa. In the corresponding areas, the VBM analysis showed an inverse correlation between the results obtained from the visual evaluation scales with the volume of the grey matter and a direct correlation between the same results with the cerebrospinal fluid volume. CONCLUSIONS: A visually based rating scale for parieto-occipital sulcus can distinguish Posterior Cortical Atrophy from typical Alzheimer disease.

Testing the 2018 NIA-AA research framework in a retrospective large cohort of patients with cognitive impairment: from biological biomarkers to clinical syndromes.

BACKGROUND: According to the 2018 NIA-AA research framework, Alzheimer's disease (AD) is not defined by the clinical consequences of the disease, but by its underlying pathology, measured by biomarkers. Evidence of both amyloid-ß (Aß) and phosphorylated tau protein (p-tau) deposition-assessed interchangeably with amyloid-positron emission tomography (PET) and/or cerebrospinal fluid (CSF) analysis-is needed to diagnose AD in a living person. Our aim was to test the new NIA-AA research framework in a large cohort of cognitively impaired patients to evaluate correspondence between the clinical syndromes and the underlying pathologic process testified by biomarkers. METHODS: We retrospectively analysed 628 subjects referred to our centre in suspicion of dementia, who underwent CSF analysis, together with neuropsychological assessment and neuroimaging, and were diagnosed with different neurodegenerative dementias according to current criteria, or as cognitively unimpaired. Subjects were classified considering CSF biomarkers, and the prevalence of normal, AD-continuum and non-AD profiles in each clinical syndrome was calculated. The positivity threshold of each CSF biomarker was first assessed by receiver operating characteristic analysis, using Aß-positive/negative status as determined by amyloid-PET visual reads. The agreement between CSF and amyloid-PET data was also evaluated. RESULTS: Among patients with a clinical diagnosis of AD, 94.1% were in the AD-continuum, whereas 5.5% were classified as non-AD and 0.4% were normal. The AD-continuum profile was found also in 26.2% of frontotemporal dementia, 48.6% of Lewy body dementia, 25% of atypical parkinsonism and 44.7% of vascular dementia. Biomarkers' profile did not differ in amnestic and not amnestic mild cognitive impairment. CSF Aß levels and amyloid-PET tracer binding negatively correlated, and the concordance between the two Aß biomarkers was 89%. CONCLUSIONS: The examination of the 2018 NIA-AA research framework in our clinical setting revealed a good, but incomplete, correspondence between the clinical syndromes and the underlying pathologic process measured by CSF biomarkers. The AD-continuum profile resulted to be a sensitive, but non-specific biomarker with regard to the clinical AD diagnosis. CSF and PET Aß biomarkers were found to be not perfectly interchangeable to quantify the Aß burden, possibly because they measure different aspects of AD pathology.

Monozygotic Twins with Frontotemporal Dementia Due To Thr272fs GRN Mutation Discordant for Age At Onset.

We report the case of two monozygotic twins with Thr272fs mutation in progranulin gene. Both patients developed frontotemporal dementia with 5 years difference in age at onset (Twin 1:73 years, Twin 2:68 years), with early behavioral, language, dysexecutive, and memory problems. They had the same formal education (5 years), but while Twin 1 dedicated more to social and leisure activity, Twin 2 worked all her life. At neuroimaging (MRI for Twin 1 and CT for Twin 2), they both showed asymmetric atrophy with left predominance. The two were discordant for total tau levels in cerebrospinal fluid, neuropsychological testing, and smoking habits. The description of the twins can help identify environmental factors that influence the onset and phenotype of frontotemporal dementia.