Categoría: Papers con abstracts

The vegetative state (VS) is characterized by the absence of awareness of self or the environment and preserved autonomic functions. The diagnosis relies critically on the lack of consistent signs of purposeful behavior in response to external stimulation. Yet, given that patients with disorders of consciousness often exhibit fragmented movement patterns, voluntary actions may go unnoticed. Here we designed a simple motor paradigm that could potentially detect signs of purposeful behavior in VS patients with mild to severe brain damage by examining the neural correlates of motor preparation in response to verbal commands. Twenty-four patients who met the diagnostic criteria for VS were recruited for this study. Eleven of these patients showing preserved auditory evoked potentials underwent functional magnetic resonance imaging (fMRI) to test for basic speech processing. Five of these patients, who showed word related activity, were included in a second fMRI study aimed at detecting functional changes in premotor cortex elicited by specific verbal instructions to move either their left or their right hand. Despite the lack of overt muscle activity, two patients out of five activated the dorsal premotor cortex contralateral to the instructed hand, consistent with movement preparation. Our results may reflect residual voluntary processing in these two patients. We believe that the identification of positive results with fMRI using this simple task, may complement the clinical assessment by helping attain a more precise diagnosis in patients with disorders of consciousness.

The emerging impact of social neuroscience on neuropsychiatry and clinical neuroscience. Autores Mendez MF, Manes F.  Año 2011 Journal  Mendez MF, Manes F.  Volumen 6(5-6): 415-419 Abstract   Otra información    

This article provides a classification of primary progressive aphasia (PPA) and its 3 main variants to improve the uniformity of case reporting and the reliability of research results. Criteria for the 3 variants of PPA–nonfluent/agrammatic, semantic, and logopenic–were developed by an international group of PPA investigators who convened on 3 occasions to operationalize earlier published clinical descriptions for PPA subtypes. Patients are first diagnosed with PPA and are then divided into clinical variants based on specific speech and language features characteristic of each subtype. Classification can then be further specified as «imaging-supported » if the expected pattern of atrophy is found and «with definite pathology » if pathologic or genetic data are available. The working recommendations are presented in lists of features, and suggested assessment tasks are also provided. These recommendations have been widely agreed upon by a large group of experts and should be used to ensure consistency of PPA classification in future studies. Future collaborations will collect prospective data to identify relationships between each of these syndromes and specific biomarkers for a more detailed understanding of clinicopathologic correlations.

When context is hard to integrate: cortical measures of congruency in schizophrenics and healthy relatives from multiplex families. Autores Ibanez A, Riveros R, Aravena P, Vergara V, Cardona JF, Garcia L, Hurtado E, Martin-Reyes M, Barutta J, Manes F.  Año 2011 Journal  Ibanez A, Riveros R, Aravena P, Vergara V, Cardona JF, Garcia L, Hurtado E, Martin-Reyes M, Barutta J, Manes F.  Volumen 126(1-3): 303-305 Abstract   Otra información    

To investigate the presence of apathy symptoms in adolescents and adults with ADHD as a behavioral manifestation of underlying motivational deficits and to determine whether apathy symptoms were associated with a specific neuropsychological profile. METHOD: A total of 38 ADHD participants (28 of the combined subtype [ADHD/C] and 10 of the inattentive subtype [ADHD/I]) and 30 healthy controls (Ctrl) were assessed on two measures of apathy administered to subjects and informants. As well, ADHD participants completed a comprehensive neuropsychological battery. RESULTS: ADHD participants presented elevated scores on measures of apathy relative to controls (ADHD/I > ADHD/C > Ctrl). Informant-based ratings of apathy correlated significantly with behavioral measures of inattention. Apathy measures correlated significantly with executive tests, working memory, verbal fluency, and general intellectual abilities, only in the inattentive sample. CONCLUSIONS: This study stresses the relevance of motivational deficits in adult ADHD as a significant clinical dimension closely linked to inattention and executive difficulties.

OBJECTIVES: Bipolar Disorders are among the ten leading causes of morbity and lithium is considered first-line treatment and the most cost-effective. Nevertheless, its use takes a back seat to other treatment options less effective, safe and more expensive; and the reasons for this remains unclear. The present study investigates clinical concepts related to its underutilization. METHOD: An anonymous questionnaire concerning different aspects of lithium clinical use (compared efficacy, adverse effects, practical aspects regarding its use, use in special populations) was administered during the XXV Congress of the Argentinean Psychiatrist Association. RESULTS: 164 questionnaires were analyzed. Less than one-third of the sample referred lithium as their most frequent treatment option, although almost 60% qualified it as effective. Almost two-thirds considered its utilization as more complex and ill-ascribed adverse effects to it. One third referred not to use it in youth and senior populations. CONCLUSIONS: contrary to current recommendations, lithium is under utilized. This is the first report on the possible causes leading to such phenomena, which can be related to ill concepts regarding its safety, clinical use and adverse effects; although not to its effectiveness.

Over a 100 years have passed since Pick’s description of what is now termed frontotemporal lobar degeneration (FTLD). FTLD is a topic of intense current research interest yet some relevant contributions by non-English speaking authors have received little attention, which makes the history of FTLD research incomplete. In the hopes of filling some of the gaps in the history of FTLD research, the present article introduces fundamental work carried out in Argentina during the first half of the 20th century by Christfried Jakob and Braulio A. Moyano. Jakob’s neurophilosophy, as well as his empirical descriptions on dementia and theoretic insights into the role of the frontal lobes are highlighted. Moyano’s works on frontotemporal dementia (FTD), specifically concerning language deficits and the concept of focal pathology in Alzheimer disease presenting with progressive aphasia are introduced. These early contributions are examined in the light of the current knowledge on FTLD, highlighting some of the authors’ early original contributions, as well as their misconceptions. These authors remain largely unknown despite the fact that their contributions were fundamental in kindling interest in behavioral neurology in Latin America, which continues to this day.

Over the past five to ten years, neuroimaging capability for neurodegenerative diseases has made remarkable progress. However, debate remains as to the true clinical utility of these advanced and costly investigations. Not only is the place of these tests in diagnostic algorithms unclear, but the access to them varies both within and between countries. We sought to gather informed opinion from recognized leaders in the field who can combine both an academic and a clinical perspective on the use of neuroimaging in their own countries. Opinion is presented from Scotland, Argentina, the Czech Republic, France, the USA and Australia. The emerging consensus was one of ongoing caution. While in most countries there was a sense that the use of more advanced imaging techniques was growing, their hour has not yet cometh. However, these techniques, rather than falling from the Ivory Tower, should descend slowly step by step onto fertile and receptive clinics from where better clinical guidelines will emerge.

Postural deformities are frequent and disabling complications of Parkinson’s disease (PD) and atypical parkinsonism. These deformities include camptocormia, antecollis, Pisa syndrome, and scoliosis. Recognition of specific postural syndromes might have differential diagnostic value in patients presenting with parkinsonism. The evidence to date suggests that postural deformities have a multifactorial pathophysiology. Contributing factors include muscular rigidity; axial dystonia; weakness caused by myopathy; body scheme defects due to centrally impaired proprioception; and structural changes in the spine. The relative contribution of these different factors varies between patients and across specific syndromes. Improved understanding of the mechanisms underlying postural deformities in PD might ultimately lead us to more effective management strategies for these disabling and drug-refractory complications.

Previous research on semantic dementia (SD) has demonstrated a link between conceptual representations and ability on a range of ´non-semantic´ tasks, both verbal and nonverbal. In all cases, SD patients perform well on items that conform to the underlying statistical ´surface´ structure of the domain in question but poor performance on items that are atypical with respect to these statistics. For such items, there is a strong tendency for the patients´ erroneous responses to reflect the more typical pattern. To date, most research on this topic has been conducted with English-speaking patients, and where extended to non-English languages, directly comparable aspects of each language have been probed. In this study we tested the generalisation of this theory by probing performance on an aspect of Spanish with no analogue in English (grammatical gender). As predicted, Spanish SD patients provided the correct gender to high frequency words or where the phonology of the noun strongly predicted the gender. For low frequency, atypical nouns, however, the patients made many more errors (preferring the statistically typical gender). As expected, performance on nouns with atypical grammatical gender was strongly correlated with the degree of semantic impairment across the case-series of SD patients.

The results not only provide another example of the critical relationship between semantic memory and ´non-semantic´ cognition, but also indicate that this theoretical framework generalises to novel aspects of non-English languages – suggesting that the phenomenon is based on brain-general mechanisms.