L-serine treatment in patients with GRIN-related encephalopathy: a phase 2A, non-randomized study.

GRIN-related disorders are rare developmental encephalopathies with variable manifestations and limited therapeutic options. Here, we present the first non-randomized, open-label, single-arm trial (NCT04646447) designed to evaluate the tolerability and efficacy of L-serine in children with GRIN genetic variants leading to loss-of-function. In this phase 2A trial, patients aged 2-18 years with GRIN loss-of-function pathogenic variants received L-serine for 52 weeks. Primary end points included safety and efficacy by measuring changes in the Vineland Adaptive Behavior Scales, Bayley Scales, age-appropriate Wechsler Scales, Gross Motor Function-88, Sleep Disturbance Scale for Children, Pediatric Quality of Life Inventory, Child Behavior Checklist and the Caregiver-Teacher Report Form following 12 months of treatment. Secondary outcomes included seizure frequency and intensity reduction and EEG improvement. Assessments were performed 3 months and 1 day before starting treatment and 1, 3, 6 and 12 months after beginning the supplement. Twenty-four participants were enrolled (13 males/11 females, mean age 9.8 years, SD 4.8), 23 of whom completed the study. Patients had GRIN2B, GRIN1 and GRIN2A variants (12, 6 and 5 cases, respectively). Their clinical phenotypes showed 91% had intellectual disability (61% severe), 83% had behavioural problems, 78% had movement disorders and 58% had epilepsy. Based on the Vineland Adaptive Behavior Composite standard scores, nine children were classified as mildly impaired (cut-off score > 55), whereas 14 were assigned to the clinically severe group. An improvement was detected in the Daily Living Skills domain (P = 0035) from the Vineland Scales within the mild group. Expressive (P = 0.005), Personal (P = 0.003), Community (P = 0.009), Interpersonal (P = 0.005) and Fine Motor (P = 0.031) subdomains improved for the whole cohort, although improvement was mostly found in the mild group. The Growth Scale Values in the Cognitive subdomain of the Bayley-III Scale showed a significant improvement in the severe group (P = 0.016), with a mean increase of 21.6 points. L-serine treatment was associated with significant improvement in the median Gross Motor Function-88 total score (P = 0.002) and the mean Pediatric Quality of Life total score (P = 0.00068), regardless of severity. L-serine normalized the EEG pattern in five children and the frequency of seizures in one clinically affected child. One patient discontinued treatment due to irritability and insomnia. The trial provides evidence that L-serine is a safe treatment for children with GRIN loss-of-function variants, having the potential to improve adaptive behaviour, motor function and quality of life, with a better response to the treatment in mild phenotypes.

Multidimensional inhibitory signatures of sentential negation in behavioral variant frontotemporal dementia.

BACKGROUND: Processing of linguistic negation has been associated to inhibitory brain mechanisms. However, no study has tapped this link via multimodal measures in patients with core inhibitory alterations, a critical approach to reveal direct neural correlates and potential disease markers. METHODS: Here we examined oscillatory, neuroanatomical, and functional connectivity signatures of a recently reported Go/No-go negation task in healthy controls and behavioral variant frontotemporal dementia (bvFTD) patients, typified by primary and generalized inhibitory disruptions. To test for specificity, we also recruited persons with Alzheimer's disease (AD), a disease involving frequent but nonprimary inhibitory deficits. RESULTS: In controls, negative sentences in the No-go condition distinctly involved frontocentral delta (2-3 Hz) suppression, a canonical inhibitory marker. In bvFTD patients, this modulation was selectively abolished and significantly correlated with the volume and functional connectivity of regions supporting inhibition (e.g. precentral gyrus, caudate nucleus, and cerebellum). Such canonical delta suppression was preserved in the AD group and associated with widespread anatomo-functional patterns across non-inhibitory regions. DISCUSSION: These findings suggest that negation hinges on the integrity and interaction of spatiotemporal inhibitory mechanisms. Moreover, our results reveal potential neurocognitive markers of bvFTD, opening a new agenda at the crossing of cognitive neuroscience and behavioral neurology.

[Multidisciplinary care and therapeutic advances in amyotrophic lateral sclerosis]. / Manejo multidisciplinario y avances terapéuticos en la esclerosis lateral amiotrófica.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that mainly affects the motor system, resulting in progressive weakness and muscle wasting. Despite the tremendous advances in physiopathological and clinical characterization, we do not have a curative treatment yet. The progressive and fatal course of ALS makes its management particularly complex and challenging given the diversity of symptoms presenting during the disease progression. The main goal in the treatment of ALS patients is to minimize morbidity and maximize the quality of life. Currently, a series of therapeutic interventions improve the quality of life and prolong survival, including multidisciplinary care, respiratory management, and disease-modifying therapy. Within the supportive interventions, weight maintenance through nutritional and metabolic support is critical. In addition, the management of neuropsychiatric manifestations and preservation of communicative capacity before speech loss are also crucial. Lastly, early palliative care intervention is essential to optimize symptomatic management. Anticipatory guidelines to face the inevitable patient deterioration should be devised. This article updates the main therapeutic strategies used in these patients, including evolving clinical trials with promising novel therapies.

Paradigmatic De Novo GRIN1 Variants Recapitulate Pathophysiological Mechanisms Underlying GRIN1-Related Disorder Clinical Spectrum.

BACKGROUND: GRIN-related disorders (GRD), the so-called grinpathies, is a group of rare encephalopathies caused by mutations affecting GRIN genes (mostly GRIN1, GRIN2A and GRIN2B genes), which encode for the GluN subunit of the N-methyl D-aspartate (NMDA) type ionotropic glutamate receptors. A growing number of functional studies indicate that GRIN-encoded GluN1 subunit disturbances can be dichotomically classified into gain- and loss-of-function, although intermediate complex scenarios are often present. METHODS: In this study, we aimed to delineate the structural and functional alterations of GRIN1 disease-associated variants, and their correlations with clinical symptoms in a Spanish cohort of 15 paediatric encephalopathy patients harbouring these variants. RESULTS: Patients harbouring GRIN1 disease-associated variants have been clinically deeply-phenotyped. Further, using computational and in vitro approaches, we identified different critical checkpoints affecting GluN1 biogenesis (protein stability, subunit assembly and surface trafficking) and/or NMDAR biophysical properties, and their association with GRD clinical symptoms. CONCLUSIONS: Our findings show a strong correlation between GRIN1 variants-associated structural and functional outcomes. This structural-functional stratification provides relevant insights of genotype-phenotype association, contributing to future precision medicine of GRIN1-related encephalopathies.

Inside minds, beneath diseases: social cognition in amyotrophic lateral sclerosis-frontotemporal spectrum disorder.

OBJECTIVE: To compare social cognition performance between patients with amyotrophic lateral sclerosis (ALS) and those patients with behavioural variant frontotemporal dementia (bvFTD). METHODS: We included 21 participants with ALS, 20 with bvFTD and 21 healthy controls who underwent a comprehensive cognitive battery, including the short version of the Social Cognition and Emotional Assessment (Mini-SEA), which comprises the faux pas test and Facial Emotion Recognition Test (FERT); Mini-Mental State Examination; Frontal Assessment Battery; lexical fluency (F-A-S), category fluency (animals/minute), digit span (direct and backwards) tests and the Hayling test. A post hoc analysis was conducted with the patients with ALS divided into two subgroups: patients without cognitive impairment (ALScn; n=13) and patients with cognitive impairment (ALSci; n=8). RESULTS: No significant difference was noted between participant groups in terms of the age, sex and education. ALS-total group and patients with bvFTD had similar disease durations. Patients with ALSci performed poorly when compared with controls with regard to the FERT (p<0.001), the faux pas (p<0.004) and the Mini-SEA (p<0.002) total scores. Moreover, patients with bvFTD performed poorly in comparison with controls in executive and social cognition tests. The performance of patients with ALSci was similar to that of patients with bvFTD, while the performance of patients with ALScn was similar to that of controls. DISCUSSION: Our findings support a cognitive continuum between ALS and bvFTD and shed light on the cognitive heterogeneity of ALS, expanding its possible neuropsychological profiles.

GERO Cohort Protocol, Chile, 2017-2022: Community-based Cohort of Functional Decline in Subjective Cognitive Complaint elderly.

BACKGROUND: With the global population aging and life expectancy increasing, dementia has turned a priority in the health care system. In Chile, dementia is one of the most important causes of disability in the elderly and the most rapidly growing cause of death in the last 20 years. Cognitive complaint is considered a predictor for cognitive and functional decline, incident mild cognitive impairment, and incident dementia. The GERO cohort is the Chilean core clinical project of the Geroscience Center for Brain Health and Metabolism (GERO). The objective of the GERO cohort is to analyze the rate of functional decline and progression to clinical dementia and their associated risk factors in a community-dwelling elderly with subjective cognitive complaint, through a population-based study. We also aim to undertake clinical research on brain ageing and dementia disorders, to create data and biobanks with the appropriate infrastructure to conduct other studies and facilitate to the national and international scientific community access to the data and samples for research. METHODS: The GERO cohort aims the recruitment of 300 elderly subjects (> 70 years) from Santiago (Chile), following them up for at least 3 years. Eligible people are adults not diagnosed with dementia with subjective cognitive complaint, which are reported either by the participant, a proxy or both. Participants are identified through a household census. The protocol for evaluation is based on a multidimensional approach including socio-demographic, biomedical, psychosocial, neuropsychological, neuropsychiatric and motor assessments. Neuroimaging, blood and stool samples are also obtained. This multidimensional evaluation is carried out in a baseline and 2 follow-ups assessments, at 18 and 36 months. In addition, in months 6, 12, 24, and 30, a telephone interview is performed in order to keep contact with the participants and to assess general well-being. DISCUSSION: Our work will allow us to determine multidimensional risks factors associated with functional decline and conversion to dementia in elderly with subjective cognitive complain. The aim of our GERO group is to establish the capacity to foster cutting edge and multidisciplinary research on aging in Chile including basic and clinical research. TRIAL REGISTRATION: NCT04265482 in ClinicalTrials.gov. Registration Date: February 11, 2020. Retrospectively Registered.

Deficits in Emotion Recognition as Markers of Frontal Behavioral Dysfunction in Amyotrophic Lateral Sclerosis.

OBJECTIVE: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with prominent motor symptoms. Patients with ALS may also manifest frontal behavior symptoms and cognitive decline, including impairment in facial emotion recognition. The authors aimed to investigate whether deficits in emotion recognition were associated with frontal behavior symptoms in ALS. METHODS: Participants were patients with probable or definite sporadic ALS (N=21; male:female ratio, 11:10; median age, 62 years; median disease duration, 3 years) and age-matched and education-matched healthy control subjects (N=25; male:female ratio, 14:11; median age, 61 years). The Facial Emotion Recognition Test (FERT) was administered to all participants. Patients with ALS were assessed using the Cambridge Behavior Inventory-Revised and were classified into two groups according to the presence of frontal behavioral symptoms: ALS with no behavioral symptom (ALSns; N=9) and ALS with at least one behavioral symptom (ALSbs; N=12). RESULTS: Apathy and mood symptoms were the most frequent neuropsychiatric symptoms in the patient group. Patients with ALS performed worse than control subjects in the recognition of sadness (p<0.004). There were no differences between control subjects and patients in the ALSns group in all FERT scores, but the ALSbs group had lower performance than control subjects in sadness (p<0.003). CONCLUSIONS: Emotion recognition deficit may be a marker of frontal behavior in ALS.

Cognitive and Behavioral Symptoms in ALSFTD: Detection, Differentiation, and Progression.

Brief screening tools that detect and differentiate patients with amyotrophic lateral sclerosis and frontotemporal dementia (ALSFTD) from those more subtle cognitive or behavioral symptoms (ALS plus) and motor symptoms only (ALS pure) is pertinent in a clinical setting. The utility of 2 validated and data-driven tests (Mini-Addenbrooke's Cognitive Examination [M-ACE] and Motor Neuron Disease Behavioral Scale [MiND-B]) was investigated in 70 ALS patients (24 ALSFTD, 19 ALS plus, and 27 ALS pure). More than 90% of patients with ALSFTD scored at or below the cutoff on the M-ACE, whereas this was seen in only about 20% of ALS patients without dementia. The MiND-B differentiated between ALS pure and ALS plus diagnostic categories. Rasch modeling of M-ACE and MiND-B items revealed early cognitive (fluency, memory recall) and behavioral (apathy) symptoms in ALSFTD. The combined use of the M-ACE and MiND-B detects patients with ALSFTD, differentiates along the ALS continuum, and offers insight into the progression of nonmotor symptomatology in ALSFTD.

[Overlapping features of frontotemporal dementia and amyotrophic lateral sclerosis]. / Manifestaciones neuropsiquiátricas y cognitivas en demencia frontotemporal y esclerosis lateral amiotrófica: dos polos de una entidad común.

Recent genetic and neuropathologic advances support the concept that frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are overlapping multisystem disorders. While 10-15% of ALS patients fulfil criteria for FTD, features of motor neuron disease appear in approximately 15% of FTD patients, during the evolution of the disease. This overlap has been reinforced by the discovery of Transactive Response DNA Binding Protein 43 kDa (TDP43) inclusions as the main neuropathologic finding in the majority of ALS cases and almost a half of FTD cases. Also, an expansion in the intron of C9ORF72 (chromosome 9p21) has been identified in families affected by ALS, ALS-FTD and FTD. This review provides an update on the recent genetic and neuropathologic findings of ALS and FTD and a characterization of their clinical presentation forms, based on the current diagnostic criteria. Finally it underscores the importance of having a national registry of patients with ALS and FTD, to provide an earlier diagnosis and a multidisciplinary care.

Incidence of amyotrophic lateral sclerosis in Chile.

OBJECTIVE: This study aimed to estimate amyotrophic lateral sclerosis (ALS) incidence and survival rates in the Metropolitan region of Chile. METHODS: We conducted a cohort study of ALS cases in the Metropolitan Region from 2016 to 2019. A total of 219 ALS patients were recruited from Corporación ELA-Chile registry, in collaboration with neurologists from Sociedad de Neurología, Psiquiatría y Neurocirugía de Chile. We calculated incidence rates by sex and age and determined median survival from onset and diagnosis. Survival analysis used the Kaplan-Meier statistic, estimating hazard ratios for age, sex, time from symptom onset and from diagnosis using a Weibull regression model. All analyses were done using R 4.1.0. RESULTS: Overall, ALS diagnosis incidence was 0.97 cases per 100,000 inhabitants, peaking in the 70-79 age group and declining thereafter. The male-to-female ratio was 1.23. The median time to death from diagnosis was 2.3 years (95% confidence interval [CI]: 1.9-2.5), and from the first symptom, it was 3.1 years (95% CI: 2.8-3.5). CONCLUSIONS: This is the first population-based study reporting ALS incidence and survival rates in Chile's Metropolitan region. Incidence resembled other Latin American studies. Median survival from diagnosis and from the first symptom were in line with previous findings. Our results corroborated lower ALS rates in Latin America, consistent with prior research.

LAENALS: epidemiological and clinical features of amyotrophic lateral sclerosis in Latin America.

OBJECTIVE: The Latin American Epidemiologic study of ALS (LAENALS) aims to gather data on ALS epidemiology, phenotype, and risk factors in Cuba, Chile, and Uruguay, to understand the impact of genetic and environmental factors on ALS. METHODS: A harmonized data collection protocol was generated, and a Latin-American Spanish language Register was constructed. Patient data were collected in Uruguay in 2018, in Chile from 2017 to 2019, and in Cuba between 2017 and 2018. Statistical analysis was performed using SPSS 25.0.0 software. Crude cumulative incidence, standardized incidence, and prevalence were calculated in the population aged 15 years and older. RESULTS: During 2017-2019, 90 people with ALS from Uruguay (55.6% men), 219 from Chile (54.6% men), and 49 from Cuba (55.1% men) were included. The cumulative crude incidence in 2018 was 1.73/100,000 persons in Uruguay, 1.08 in Chile and 0.195 in Cuba. Crude prevalence in 2018 was 2.19 per 100,000 persons in Uruguay, 1.39 in Chile and 0.55 in Cuba. Mean age at onset was 61.8 ± 11.96 SD years in Uruguay, 61.9 ± 10.4 SD years in Chile, and 60.21 ± 12.45 SD years in Cuba (p = 0.75). Median survival from onset was 32.43 months (21.93 - 42.36) in Uruguay, 24 months (13.5 - 33.5) in Chile, and 29 months (15 - 42.5) in Cuba (p = 0.006). CONCLUSIONS: These preliminary data from LAENALS confirm the lower incidence and prevalence of ALS in counties with admixed populations. The LAENALS database is now open to other Latin American countries for harmonized prospective data collection.

Assessing subjective cognitive decline in older adults attending primary health care centers: what question should be asked?

INTRODUCTION: Subjective Cognitive Decline (SCD) refers to a self-perceived experience of decreased cognitive function without objective signs of cognitive impairment in neuropsychological tests or daily living activities. Despite the abundance of instruments addressing SCD, there is no consensus on the methods to be used. Our study is founded on 11 questions selected due to their recurrence in most instruments. The objective was to determine which one of these questions could be used as a simple screening tool. METHODS: 189 participants aged 65 and over selected from Primary Care centers in Santiago de Chile responded to these 11 questions and were evaluated with the MiniMental State Examination (MMSE), the Free and Cued Selective Reminding Test (FCSRT), the Pfeffer functional scale, and the Geriatric Depression Scale (GDS). An Item ResponseTheory (IRT) method was performed to assess the contribution of each of the 11 questions to the SCD latent trait and its discrimination ability. RESULTS: Based on the results of the exploratory factor analysis showing very high/low saturation of several questions on the factors, and the high residual correlation between some questions, the IRT methods led to select one question ("Do you feel like your memory has become worse?") which revealed to be the most contributive and discriminant. Participants who answered yes had a higher GDS score. There was no association with MMSE, FCSRT, and Pfeffer scores. CONCLUSION: The question "Do you feel like your memory has become worse?" may be a good proxy of SCD and could be included in routine medical checkups.

The "when" matters: Evidence from memory markers in the clinical continuum of Alzheimer's disease.

OBJECTIVE: Cognitive assessment able to detect impairments in the early neuropathological stages of Alzheimer's disease (AD) is urgently needed. The visual short-term memory binding task (VSTMBT) and the Free and Cued Selective Reminding Test (FCSRT) have been recommended by the neurodegenerative disease working group as promising tests to aid in the early detection of AD. In this study, we investigated their complementary value across the clinical stages of the AD continuum. METHOD: One hundred and seventeen older adults with subjective cognitive complaint (SCC), 79 with mild cognitive impairment (MCI), 31 patients with AD dementia (ADD), and 37 cognitively unimpaired (CU) subjects, underwent assessment with the VSTMBT and the picture version of the Spanish FCSRT. RESULTS: After controlling for multiple comparisons, significant differences were found across groups. The VSTMBT was the only test that "marginally" differentiated between CU and SCC (d = 0.47, p = .052). Moreover, whereas the FCSRT showed a gradient (CU = SCC) > MCI > ADD, the VSTMBT gradient was CU > SCC > (MCI = ADD) suggesting that conjunctive binding deficits assessed by the latter may be sensitive to the very early stages of the disease. CONCLUSIONS: Our results suggest that the VSTMBT and the FCSRT are sensitive to the clinical continuum of AD. Whereas the former detects changes in the early prodromal stages, the latter is more sensitive to the advanced prodromal stages of AD. These novel tests can aid in the early detection, monitor disease progression and response to treatment, and thus support drug development programs. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Moral Emotions and Their Brain Structural Correlates Across Neurodegenerative Disorders.

BACKGROUND: Although social cognition is compromised in patients with neurodegenerative disorders such as behavioral variant frontotemporal dementia (bvFTD) and Alzheimer's disease (AD), research on moral emotions and their neural correlates in these populations is scarce. No previous study has explored the utility of moral emotions, compared to and in combination with classical general cognitive state tools, to discriminate bvFTD from AD patients. OBJECTIVE: To examine self-conscious (guilt and embarrassment) and other-oriented (pity and indignation) moral emotions, their subjective experience, and their structural brain underpinnings in bvFTD (n = 31) and AD (n = 30) patients, compared to healthy controls (n = 37). We also explored the potential utility of moral emotions measures to discriminate bvFTD from AD. METHODS: We used a modified version of the Moral Sentiment Task measuring the participants' accuracy scores and their emotional subjective experiences. RESULTS: bvFTD patients exhibited greater impairments in self-conscious and other-oriented moral emotions as compared with AD patients and healthy controls. Moral emotions combined with general cognitive state tools emerged as useful measures to discriminate bvFTD from AD patients. In bvFTD patients, lower moral emotions scores were associated with lower gray matter volumes in caudate nucleus and inferior and middle temporal gyri. In AD, these scores were associated with lower gray matter volumes in superior and middle frontal gyri, middle temporal gyrus, inferior parietal lobule and supramarginal gyrus. CONCLUSION: These findings contribute to a better understanding of moral emotion deficits across neurodegenerative disorders, highlighting the potential benefits of integrating this domain into the clinical assessment.

Heterogeneous factors influence social cognition across diverse settings in brain health and age-related diseases.

Aging may diminish social cognition, which is crucial for interaction with others, and significant changes in this capacity can indicate pathological processes like dementia. However, the extent to which non-specific factors explain variability in social cognition performance, especially among older adults and in global settings, remains unknown. A computational approach assessed combined heterogeneous contributors to social cognition in a diverse sample of 1063 older adults from 9 countries. Support vector regressions predicted the performance in emotion recognition, mentalizing, and a total social cognition score from a combination of disparate factors, including clinical diagnosis (healthy controls, subjective cognitive complaints, mild cognitive impairment, Alzheimer's disease, behavioral variant frontotemporal dementia), demographics (sex, age, education, and country income as a proxy of socioeconomic status), cognition (cognitive and executive functions), structural brain reserve, and in-scanner motion artifacts. Cognitive and executive functions and educational level consistently emerged among the top predictors of social cognition across models. Such non-specific factors showed more substantial influence than diagnosis (dementia or cognitive decline) and brain reserve. Notably, age did not make a significant contribution when considering all predictors. While fMRI brain networks did not show predictive value, head movements significantly contributed to emotion recognition. Models explained between 28-44% of the variance in social cognition performance. Results challenge traditional interpretations of age-related decline, patient-control differences, and brain signatures of social cognition, emphasizing the role of heterogeneous factors. Findings advance our understanding of social cognition in brain health and disease, with implications for predictive models, assessments, and interventions.

Amyotrophic lateral sclerosis and frontotemporal dementia: A behavioural and cognitive continuum.

Our objective was to compare the cognitive and behavioural profile of patients with amyotrophic lateral sclerosis (ALS) and behavioural variant frontotemporal dementia (bvFTD), and to explore the continuum between these disorders according to neuropsychological and behavioural performance using novel methods of testing and analysis. Twenty patients with ALS, 20 bvFTD patients and 20 healthy controls completed a neuropsychiatric and neuropsychological assessment including cognitive screening, working memory, inhibitory control, decision making and emotion recognition. The resulting neuropsychological and behavioural data were analysed by Rasch analysis. ALS patients showed a similar profile to bvFTD patients on tests of working memory, inhibitory control and behavioural measures. Nine ALS patients (45%) had cognitive impairment and five (25%) met criteria for bvFTD. Even in a subset of MND patients with no impairment on the ACE-R, subtle impairment of inhibitory control together with moderate to severe apathy, were found. The Rasch analysis confirmed that all patients could be ranked on the same continuum, based on their neuropsychological performance and behaviour. Thus, the cognitive and behavioural profiles of ALS mirror those seen in bvFTD. Impaired inhibitory control and behavioural changes suggest subtle orbitofrontal dysfunction in ALS. The Rasch analysis revealed a clear overlap between bvFTD and ALS.

Caregiver burden in amyotrophic lateral sclerosis is more dependent on patients' behavioral changes than physical disability: a comparative study.

BACKGROUND: Behavioral changes in patients with amyotrophic lateral sclerosis (ALS) mirror those found in frontotemporal dementia (FTD). Considering the high rate of neuropsychiatric symptoms found in ALS patients, this paper examines whether caregiver burden is associated with behavioral changes over and above the physical disability of patients with ALS, and if the presence of caregivers' depression, anxiety and stress also impacts on caregiver burden. METHODS: 140 caregivers of patients with ALS participated in a postal survey investigating patients' neuropsychiatric symptoms (Cambridge Behaviour Inventory Revised CBI-R), motor function (Amyotrophic Lateral Sclerosis Functional Rating Scale Revised - ALSFRS-R), caregiver burden (Zarit Burden Interview), and caregiver mood (Depression, Anxiety and Stress Scale- DASS21). Seventy four percent of them were caregivers of patients with limb onset and 25.7% were caregivers of patients with bulbar onset. RESULTS: Moderate to severe behavioral changes were reported in 10-40% of patients with ALS. The levels of depression, anxiety and stress in the caregivers reached 20%. Burden was high in 48% of the caregivers. The strongest predictor of high caregiver burden was ALS patients' abnormal behavior rather than physical disability, with an odds ratio of 1.4, followed by caregivers' stress. CONCLUSIONS: Our study has identified that behavioral changes (e.g. disinhibition, impulsivity) and caregiver stress have greater impact on caregiver burden than level and pattern of physical disability.

Sensitivity of revised diagnostic criteria for the behavioural variant of frontotemporal dementia.

Based on the recent literature and collective experience, an international consortium developed revised guidelines for the diagnosis of behavioural variant frontotemporal dementia. The validation process retrospectively reviewed clinical records and compared the sensitivity of proposed and earlier criteria in a multi-site sample of patients with pathologically verified frontotemporal lobar degeneration. According to the revised criteria, 'possible' behavioural variant frontotemporal dementia requires three of six clinically discriminating features (disinhibition, apathy/inertia, loss of sympathy/empathy, perseverative/compulsive behaviours, hyperorality and dysexecutive neuropsychological profile). 'Probable' behavioural variant frontotemporal dementia adds functional disability and characteristic neuroimaging, while behavioural variant frontotemporal dementia 'with definite frontotemporal lobar degeneration' requires histopathological confirmation or a pathogenic mutation. Sixteen brain banks contributed cases meeting histopathological criteria for frontotemporal lobar degeneration and a clinical diagnosis of behavioural variant frontotemporal dementia, Alzheimer's disease, dementia with Lewy bodies or vascular dementia at presentation. Cases with predominant primary progressive aphasia or extra-pyramidal syndromes were excluded. In these autopsy-confirmed cases, an experienced neurologist or psychiatrist ascertained clinical features necessary for making a diagnosis according to previous and proposed criteria at presentation. Of 137 cases where features were available for both proposed and previously established criteria, 118 (86%) met 'possible' criteria, and 104 (76%) met criteria for 'probable' behavioural variant frontotemporal dementia. In contrast, 72 cases (53%) met previously established criteria for the syndrome (P < 0.001 for comparison with 'possible' and 'probable' criteria). Patients who failed to meet revised criteria were significantly older and most had atypical presentations with marked memory impairment. In conclusion, the revised criteria for behavioural variant frontotemporal dementia improve diagnostic accuracy compared with previously established criteria in a sample with known frontotemporal lobar degeneration. Greater sensitivity of the proposed criteria may reflect the optimized diagnostic features, less restrictive exclusion features and a flexible structure that accommodates different initial clinical presentations. Future studies will be needed to establish the reliability and specificity of these revised diagnostic guidelines.

Standardization and diagnostic utility of the Frontal Assessment Battery for healthy people and patients with dementia in the Chilean population.

The Frontal Assessment Battery (FAB) is a screening test that measures executive functions. Although this instrument has been validated in several countries, its diagnostic utility in a Chilean population has not been studied yet. Objectives: This study aimed to (1) adapt FAB in a Chilean population; (2) study the psychometric properties of the FAB in a Chilean population; (3) assess the sociodemographic influence in the performance of the FAB in a sample of healthy controls (HC); and (4) develop normative data for this healthy group. Methods: A HC (n=344) and a group of patients with dementia (n=156) were assessed with the Chilean version of FAB. Results: FAB showed good internal consistency (Cronbach's alpha=0.79) and acceptable validity based on the relationship with other variables. Factor analysis showed the unidimensionality of the instrument. Significant differences were found in the total FAB value between the HC and dementia groups. With the matched sample, the established cutoff point was 13.5, showing a sensitivity of 80.8% and a specificity of 90.4%. Regression analysis showed that education and age significantly predicted FAB performance in the healthy group. Finally, normative data are provided. Conclusions: This study shows that FAB is a useful tool to discriminate between healthy people and people with dementia. However, further studies are needed to explore the capacity of the instrument to characterize the dysexecutive syndrome in people with dementia in the Chilean population.

A Bateria de Avaliação Frontal (FAB) é um teste de rastreio que mede as funções executivas. Embora esse instrumento tenha sido validado em vários países, sua utilidade diagnóstica em uma população chilena ainda não foi estudada. Objetivos: (1) Adaptar a FAB para uma população chilena; (2) estudar as propriedades psicométricas da FAB em uma população chilena; (3) avaliar a influência sociodemográfica no desempenho da FAB em uma amostra de controles saudáveis; e (4) desenvolver dados normativos para este último grupo. Métodos: Um grupo controle saudável (n=344) e um grupo de pacientes com demência (n=156) foram avaliados com a versão chilena da FAB. Resultados: A FAB apresentou boa consistência interna (alfa de Cronbach=0,79) e validade aceitável com base na relação com outras variáveis. A análise fatorial mostrou a unidimensionalidade do instrumento. Diferenças significativas foram encontradas no valor total da FAB entre os grupos controle saudável e demência. Com a amostra pareada, o ponto de corte estabelecido foi de 13,5, que apresentou sensibilidade de 80,8% e especificidade de 90,4%. A análise de regressão mostrou que a escolaridade e a idade predisseram significativamente o desempenho da FAB no grupo saudável. Finalmente, os dados normativos são fornecidos. Conclusões: O presente estudo mostrou que a FAB é uma ferramenta útil para discriminar entre pessoas saudáveis e aquelas com demência. No entanto, mais estudos são necessários para explorar a capacidade do instrumento para caracterizar a síndrome disexecutiva em pessoas com demência na população chilena.