Chiara Cerami

White Matter Damage in Frontotemporal Lobar Degeneration Spectrum

White matter (WM) tract damage was assessed in patients with the behavioral variant frontotemporal dementia (bvFTD) and the 3 primary progressive aphasia (PPA) variants and compared with the corresponding brain atrophy patterns. Thirteen bvFTD and 20 PPA patients were studied. Tract-based spatial statistics and voxel-based morphometry were used. Patients with bvFTD showed widespread diffusion tensor magnetic resonance imaging (DT MRI) abnormalities affecting most of the WM bilaterally. In PPA patients, WM damage was more focal and varied across the 3 syndromes: left frontotemporoparietal in nonfluent, left frontotemporal in semantic, and left frontoparietal in logopenic patients. In each syndrome, DT MRI changes extended beyond the topography of gray matter loss. Left uncinate damage was the best predictor of frontotemporal lobar degeneration diagnosis versus controls. DT MRI measures of the anterior corpus callosum and left superior longitudinal fasciculus differentiated bvFTD from nonfluent cases. The best predictors of semantic PPA compared with both bvFTD and nonfluent cases were diffusivity abnormalities of the left uncinate and inferior longitudinal fasciculus. This study provides insights into the similarities and differences of WM damage in bvFTD and PPA variants. DT MRI metrics hold promise to serve as early markers of WM integrity loss that only at a later stage may be detectable by volumetric measures.

A Standardized [18F]-FDG-PET Template for Spatial Normalization in Statistical Parametric Mapping of Dementia

Abstract[18F]-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) is a widely used diagnostic tool that can detect and quantify pathophysiology, as assessed through changes in cerebral glucose metabolism. [18F]-FDG PET scans can be analyzed using voxel-based statistical methods such as Statistical Parametric Mapping (SPM) that provide statistical maps of brain abnormalities in single patients. In order to perform SPM, a “spatial normalization” of an individual’s PET scan is required to match a reference PET template. The PET template currently used for SPM normalization is based on [15O]-H2O images and does not resemble either the specific metabolic features of [18F]-FDG brain scans or the specific morphological characteristics of individual brains affected by neurodegeneration. Thus, our aim was to create a new [18F]-FDG PET aging and dementia-specific template for spatial normalization, based on images derived from both age-matched controls and patients. We hypothesized that this template would increase spatial normalization accuracy and thereby preserve crucial information for research and diagnostic purposes. We investigated the statistical sensitivity and registration accuracy of normalization procedures based on the standard and new template—at the single-subject and group level—independently for subjects with Mild Cognitive Impairment (MCI), probable Alzheimer’s Disease (AD), Frontotemporal lobar degeneration (FTLD) and dementia with Lewy bodies (DLB). We found a significant statistical effect of the population-specific FDG template-based normalisation in key anatomical regions for each dementia subtype, suggesting that spatial normalization with the new template provides more accurate estimates of metabolic abnormalities for single-subject and group analysis, and therefore, a more effective diagnostic measure.

Autosomal Dominant Frontotemporal Lobar Degeneration Due to the C9ORF72 Hexanucleotide Repeat Expansion: Late-Onset Psychotic Clinical Presentation

BACKGROUND A hexanucleotide repeat expansion in the first intron of C9ORF72 has been shown to be responsible for a high number of familial cases of amyotrophic lateral sclerosis or frontotemporal lobar degeneration (FTLD). Atypical presentations have been described, particularly psychosis. METHODS We determined the frequency of the hexanucleotide repeat expansions in a population of 651 FTLD patients and compared the clinical characteristics of carriers and noncarriers. In addition, we genotyped 21 patients with corticobasal syndrome, 31 patients with progressive supranuclear palsy, and 222 control subjects. RESULTS The pathogenic repeat expansion was detected in 39 (6%) patients with FTLD (17 male and 22 female subjects); however, it was not detected in any corticobasal syndrome and progressive supranuclear palsy patients or controls. Twenty-four of 39 carriers had positive family history for dementia and/or amyotrophic lateral sclerosis (61.5%), whereas only 145 of 612 noncarriers had positive family history (23.7%; p<.000001). Clinical phenotypes of carriers included 29 patients with the behavioral variant frontotemporal dementia (bvFTD; 5.2% of all bvFTD cases), 8 with bvFTD/motor neuron disease (32% bvFTD/motor neuron disease cases), 2 with semantic dementia (5.9% of patients with semantic dementia), and none with progressive nonfluent aphasia. The presentation with late-onset psychosis (median age = 63 years) was more frequent in carriers than noncarriers (10/33 vs. 3/37, p = .029), as well as the presence of cognitive impairment at onset (15/33 vs. 5/37; p = .0039). CONCLUSIONS The repeat expansion in C9ORF72 is a common cause of FTLD and often presents with late-onset psychosis or memory impairment.

Strategic roadmap for an early diagnosis of Alzheimer's disease based on biomarkers

The diagnosis of Alzheimers disease can be improved by the use of biological measures. Biomarkers of functional impairment, neuronal loss, and protein deposition that can be assessed by neuroimaging (ie, MRI and PET) or CSF analysis are increasingly being used to diagnose Alzheimers disease in research studies and specialist clinical settings. However, the validation of the clinical usefulness of these biomarkers is incomplete, and that is hampering reimbursement for these tests by health insurance providers, their widespread clinical implementation, and improvements in quality of health care. We have developed a strategic five-phase roadmap to foster the clinical validation of biomarkers in Alzheimers disease, adapted from the approach for cancer biomarkers. Sufficient evidence of analytical validity (phase 1 of a structured framework adapted from oncology) is available for all biomarkers, but their clinical validity (phases 2 and 3) and clinical utility (phases 4 and 5) are incomplete. To complete these phases, research priorities include the standardisation of the readout of these assays and thresholds for normality, the evaluation of their performance in detecting early disease, the development of diagnostic algorithms comprising combinations of biomarkers, and the development of clinical guidelines for the use of biomarkers in qualified memory clinics.

Validation of an optimized SPM procedure for FDG-PET in dementia diagnosis in a clinical setting

Diagnostic accuracy in FDG-PET imaging highly depends on the operating procedures. In this clinical study on dementia, we compared the diagnostic accuracy at a single-subject level of a) Clinical Scenarios, b) Standard FDG Images and c) Statistical Parametrical (SPM) Maps generated via a new optimized SPM procedure. We evaluated the added value of FDG-PET, either Standard FDG Images or SPM Maps, to Clinical Scenarios. In 88 patients with neurodegenerative diseases (Alzheimers Disease—AD, Frontotemporal Lobar Degeneration—FTLD, Dementia with Lewy bodies—DLB and Mild Cognitive Impairment—MCI), 9 neuroimaging experts made a forced diagnostic decision on the basis of the evaluation of the three types of information. There was also the possibility of a decision of normality on the FDG-PET images. The clinical diagnosis confirmed at a long-term follow-up was used as the gold standard. SPM Maps showed higher sensitivity and specificity (96% and 84%), and better diagnostic positive (6.8) and negative (0.05) likelihood ratios compared to Clinical Scenarios and Standard FDG Images. SPM Maps increased diagnostic accuracy for differential diagnosis (AD vs. FTD; beta 1.414, p = 0.019). The AUC of the ROC curve was 0.67 for SPM Maps, 0.57 for Clinical Scenarios and 0.50 for Standard FDG Images. In the MCI group, SPM Maps showed the highest predictive prognostic value (mean LOC = 2.46), by identifying either normal brain metabolism (exclusionary role) or hypometabolic patterns typical of different neurodegenerative conditions.

Emotional empathy in amyotrophic lateral sclerosis: a behavioural and voxel-based morphometry study

Abstract Amyotrophic lateral sclerosis (ALS) is a multisystem condition, in which executive and/or behavioural symptoms can occur. Deficits of social cognition, including defective cognitive and emotional empathy, have been recently reported in ALS subjects. The neurostructural correlates of these disorders in ALS are still unknown. The aims of this study were to evaluate two components of empathy in non-demented ALS subjects, and to associate performance with regional grey-matter density using voxel-based morphometry (VBM). Twenty non-demented sporadic probable or definite ALS patients and 56 matched healthy controls (HC) participated in a non-verbal task requiring the attribution of emotional versus cognitive states to identify the correct ending of comic strips, compared with a control condition requiring identifying causal relationships devoid of social components. A subgroup of 14 ALS and 20 HC joined the VBM study. Results demonstrated that, compared with controls, ALS patients showed defective emotional empathy attribution, related with reduced grey-matter density in the anterior cingulate cortex and right inferior frontal gyrus. Our study provided evidence of a specific impairment of emotional empathy in ALS patients, reflecting neural damage in a limbic prefrontal network involved in emotional processing. Social cognition disorders may represent a marker of cognitive dysfunction in ALS.

Microstructural white matter correlates of emotion recognition impairment in Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is associated in about half of the cases with behavioral and cognitive disorders, including impairments in socio-emotional processing, considered as key-features for the diagnosis of the behavioral variant of frontotemporal dementia (bv-FTD). The neurostructural bases of emotional deficits in ALS, however, still remain largely unexplored. Here we aim to assess emotion recognition in non-demented sporadic ALS patients compared with healthy controls, and to explore for the first time its microstructural white-matter correlates. Twenty-two subjects with either probable or definite diagnosis of ALS and 55 age-, gender-, and education-matched healthy controls were recruited in the study. All participants performed the Ekman 60-Faces Test, assessing the recognition of six basic emotions (i.e., anger, disgust, fear, sadness, surprise and happiness). A subgroup of subjects, comprising 19 patients and 20 healthy controls, also underwent a Diffusion Tensor Imaging scanning. Behavioral analysis highlighted a significant decline of emotion recognition skills in patients compared to controls, particularly affecting the identification of negative emotions. Moreover, the Diffusion Tensor Imaging analyses revealed a correlation between this impairment and the alteration of white-matter integrity along the right inferior longitudinal fasciculus and inferior fronto-occipital fasciculus. Our findings indicate the presence of an early emotion recognition deficit in non-demented sporadic ALS patients, associated with microstructural changes in ventral associative bundles connecting occipital, temporo-limbic and orbitofrontal regions in the right hemisphere. These changes may represent a frontotemporal-limbic microstructural marker of socio-emotional impairment in ALS.

From genotype to phenotype: Two cases of genetic frontotemporal lobar degeneration with premorbid bipolar disorder

Frontotemporal lobar degeneration (FTLD) is a common early-onset dementia, which shows highly heterogeneous phenotypic presentations. Although an autosomal dominant transmission can be found only in about 10% cases, familial aggregation is frequently observed in FTLD. Recently, the progranulin gene (GRN) was reported to be involved in the disease pathogenesis. We describe two clinically different, apparently sporadic FTLD cases, sharing the previously described GRN mutation g.11019_11022delCACT (relative to nt1, NCBI NG_007886.1), alias Thr272fs, with a premorbid psychiatric history. Both patients are males and were in their sixties when diagnosed clinically with, respectively, the behavioral variant of frontotemporal dementia (bvFTD) and progressive nonfluent aphasia (PNFA). In both cases, the medical history revealed the presence of bipolar spectrum disorders. Mutations in GRN are considered to be a major cause of FTLD. However, the phenotypes associated with these mutations are highly variable. Our description of two novel FTLD genetic cases confirms the high frequency of the g.11019_11022delCACT mutation in Northern Italy. On this basis, we recommend to consider the presence of this mutation as a possible cause of the disease, particularly in patients with premorbid psychiatric symptoms.

The cognitive and behavioural profile of Amyotrophic Lateral Sclerosis: Application of the consensus criteria

Objective: The study aims to assess the spectrum of cognitive and behavioural disorders in patients affected by Amyotrophic Lateral Sclerosis (ALS) according to the recent consensus criteria [9]. The study also intends to assess the impact of physical disability on cognitive and behavioural abnormalities. Methods: Detailed neurological, neuropsychological and neurobehavioral evaluations were administered to 23 ALS patients, 11 Lower Motor Neuron Disease (LMND) patients and 39 healthy controls. Strong et al.’s criteria [9] were applied to diagnose the presence of cognitive/behavioural impairment. Clinical and neuropsychological scores were used for group comparisons and correlation analyses. Results: In comparison with LMND and controls, a subgroup of ALS patients (∼30%) manifested executive dysfunction, which was severe enough to classify them as cognitively impaired. Action naming difficulties and short-term memory deficits were also observed. Aspontaneity, disorganization and mental rigidity reached clinical relevance in 20% of ALS patients. A small percentage of ALS patients (13%) also had comorbid dementia. The cognitive or behavioural status was not related to the clinical features of ALS. Conclusion: The use of consensus criteria for cognitive and behavioural impairment and the comparison with the LMND group proved useful in defining the spectrum of non-motor manifestations of ALS.

Neural correlates of empathic impairment in the behavioral variant of frontotemporal dementia

Loss of empathy is a symptom of the behavioral variant of frontotemporal dementia (bvFTD), constituting a clue for early diagnosis. In this study, we directly compared two empathy components (intention attribution [IA] and emotion attribution [EA]), correlating them with possible specific patterns of gray‐matter density reduction within the mentalizing network.