No abstract

To estimate the allele frequency of C9orf72 (G 4 C 2 ) repeats in amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), Alzheimer disease (AD), and Parkinson disease (PD).Design: The number of repeats was estimated by a 2-step genotyping strategy. For expansion carriers, we sequenced the repeat flanking regions and obtained APOE genotypes and MAPT H1/H2 haplotypes.Setting: Hospitals specializing in neurodegenerative disorders. Subjects:We analyzed 520 patients with FTLD, 389 patients with ALS, 424 patients with AD, 289 patients with PD, 602 controls, 18 families, and 29 patients with PD with the LRRK2 G2019S mutation.Main Outcome Measure: The expansion frequency.Results: Based on a prior cutoff (Ͼ30 repeats), the expansion was detected in 9.3% of patients with ALS, 5.2% of patients with FTLD, and 0.7% of patients with PD but not in controls or patients with AD. It was significantly Author Affil the end of th Author Affiliations are listed at the end of this article.

Recent frameworks in cognitive neuroscience and behavioral neurology underscore interoceptive priors as core modulators of negative emotions. However, the field lacks experimental designs manipulating the priming of emotions via interoception and exploring their multimodal signatures in neurodegenerative models. Here, we designed a novel task that involves interoceptive and control-exteroceptive priming conditions followed by post-Intero and post-Extero facial emotion recognition (FER). We recruited 114 participants, including healthy controls (HCs) as well as patients with behavioral variant frontotemporal dementia (bvFTD), Parkinson's disease (PD), and Alzheimer's disease (AD). We measured online EEG modulations of the heart-evoked potential (HEP), and associations with both brain structural and resting-state functional connectivity patterns. Behaviorally, post-Intero negative FER was enhanced in HCs but selectively disrupted in bvFTD and PD, with AD presenting generalized disruptions across emotion types. Only BvFTD presented impaired interoceptive accuracy. Increased HEP modulations during post-Intero negative FER was observed in HCs and AD, but not in bvFTD or PD patients. Across all groups, post-Intero negative FER correlated with the volume of the insula and the anterior cingulate cortex. Also, negative FER was associated with functional connectivity along the (a) salience network in the post-Intero condition, and along the (b) executive network in the post-Extero condition. These patterns were selectively disrupted in bvFTD (a) and PD (b), respectively.Our approach underscores the multidimensional impact of interoception on emotion, while revealing a specific pathophysiological marker of bvFTD. These findings inform a promising theoretical and clinical agenda in the fields of interoception, emotion, allostasis, and neurodegeneration.

Alzheimer's disease (AD) and frontotemporal dementia (FTD) are the most common neurodegenerative early-onset dementias. Despite the fact that both conditions have a very distinctive clinical pattern, they present with an overlap in their cognitive and behavioral features that may lead to misdiagnosis or delay in diagnosis. The current review intends to summarize briefly the main differences at the clinical, neuropsychological, and behavioral levels, in an attempt to suggest which aspects would facilitate an adequate diagnosis in a clinical setting, especially in Latin American and low-and middle-income countries, where the resources needed for a differential diagnosis (such as MRI or biomarkers) are not always available. A timely diagnosis of AD and FTD have significant implications for the medical management and quality of life of patients and careers.