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Visual short-term store can compensate for a defective phonological short-term store in patients with apraxia of speech
No full textOBJECTIVE:
The aim of the study was to investigate whether, within the phonological short-term memory (STM) system, speech articulation disorders primarily due to cortical damage are associated with deficits in the phonological recoding of visual-verbal material, and whether the visual short-term store (STS) can compensate for inefficient access to the phonological STS, as suggested in previous reports.
METHOD:
Two patients (AE and TM) with apraxia of speech due to atrophic cerebral damage were administered a battery of tasks devised to explore the organization of the phonological STM.
RESULTS:
AE's span was normal and TM's span was markedly reduced. Phonological similarity and word-length effects: Both patients showed the effects in visual presentation; the effect was less evident in verbal presentation. This suggests a phonological STS disorder and preserved rehearsal/phonological recoding, consistently with involvement of the left parietal regions, which was documented by the MRI in both patients. Unexpectedly, TM had a longer span for similar than for dissimilar words in visually presented stimuli. Silent phonology (on written material): At variance with controls, stress assignment improved during unattended speech both in AE and TM, while in both patients and controls a detrimental effect of unattended speech was documented in the initial sound task.
CONCLUSIONS:
To account for this unusual pattern of results, we hypothesized that whenever possible, AE and TM adopt the strategy that takes advantage of the visual STM store to compensate for a defective phonological STS
Posterior AD-type pathology: cognitive subtypes emerging from a cluster analysis
No full text"BACKGROUND:
"Posterior shift" of the neuropathological changes of Alzheimer's disease (AD) produces a syndrome (posterior cortical atrophy) (PCA) dominated by high-level visual deficits.
OBJECTIVE:
To explore in patients with AD-type pathology whether a data-driven analysis (cluster analysis) based on neuropsychological findings resulted in the emergence of different subgroups of patients; in particular to find out whether it was possible to identify patients with visuospatial deficits consistent with the hypothesis that PCA is a "dorsal stream" syndrome or, rather, whether there were subgroups of patients with different types of impairment within the high-level visual domain.
METHODS:
23 PCA and 16 DAT patients were studied. By a principal component analysis performed on a wide range of neuropsychological tasks, 15 variables were obtained that loaded onto five main factors (memory, language, perceptual, visuospatial, and calculation) which entered a hierarchical cluster analysis.
RESULTS:
Four clusters of cognitive impairment emerged: visuospatial/perceptual, memory, perceptual/calculation, and language. Only in the first cluster a visuospatial deficit clearly emerged. conclusions: AD pathology produces not only variants dominated by memory (DAT) and, to a lesser extent, visuospatial deficit (PCA), but also other distinct syndromic subtypes with disorders in visual perception and language which reflect a different vulnerability of specific functional networks
Posterior AD-Type Pathology: Cognitive Subtypes Emerging from a Cluster Analysis
Get PDF"Posterior shift" of the neuropathological changes of Alzheimer's disease (AD) produces a syndrome (posterior cortical atrophy) (PCA) dominated by high-level visual deficits. To explore in patients with AD-type pathology whether a data-driven analysis (cluster analysis) based on neuropsychological findings resulted in the emergence of different subgroups of patients; in particular to find out whether it was possible to identify patients with visuospatial deficits consistent with the hypothesis that PCA is a "dorsal stream" syndrome or, rather, whether there were subgroups of patients with different types of impairment within the high-level visual domain. 23 PCA and 16 DAT patients were studied. By a principal component analysis performed on a wide range of neuropsychological tasks, 15 variables were obtained that loaded onto five main factors (memory, language, perceptual, visuospatial, and calculation) which entered a hierarchical cluster analysis. Four clusters of cognitive impairment emerged: visuospatial/perceptual, memory, perceptual/calculation, and language. Only in the first cluster a visuospatial deficit clearly emerged. conclusions: AD pathology produces not only variants dominated by memory (DAT) and, to a lesser extent, visuospatial deficit (PCA), but also other distinct syndromic subtypes with disorders in visual perception and language which reflect a different vulnerability of specific functional networks
Cognitive impairment and cardiovascular disease related to alexithymia in a well-controlled HIV-infected population
No full text: Both cognitive diseases and alexithymia may be associated with HIV. Moreover, alexithymia has been linked to cardiovascular (CV) diseases. Our aim was to explore the prevalence of alexithymia and its associations with neurocognitive disorders (HAND) and CV risk factors in a well-controlled HIV-positive population. We consecutively enrolled 140 HIV-positive individuals on antiretroviral therapy and 35 healthy subjects matched for age, education and gender. In all participants alexithymia was explored by the 20-item Toronto Alexithymia Scale. For HIV-positive subjects also data about CV risk factors were collected, and a comprehensive neuropsychological examination was administered; HAND was defined according to Frascati criteria. Patients and controls did not differ in the proportion of alexithymic status (10% vs. 11%; p=0.761). Among HIV-positive patients, alexithymic participants presented a higher prevalence of diabetes (21% vs. 3%, p=0.035) and hypertension (36% vs. 13%, p= 0.037) compared to non-alexithymic. About 30% (n=41) of HIV-positive patients met criteria for asymptomatic HAND. Alexithymia was not independently associated with a higher risk of HAND (p=0.189). Analyzing each cognitive domain, alexithymia showed an independent association with an abnormal performance (OR 1.08; p=0.037) only in psychomotor speed. In conclusion, in the context of a well-controlled HIV infection, we found a low prevalence of alexithymia comparable to healthy controls. Alexithymia was linked to higher risk of CV disease in the HIV-positive population, but with a rate similar to that previously estimated in the HIV-negative alexithymic. Finally, alexithymia was clearly associated to cognitive impairment only in the psychomotor speed domain, suggesting a common fronto-striatal system dysregulation
Neuropsychological features of patients with Parkinson’s disease and impulse control disorders
No full textImpulse control disorders (ICDs) are frequent in Parkinson’s disease (PD). Aim of the present study was to investigate cognition and behaviour in PD patients with and without ICDs, in order to identify potential early clinical features which might be associated to the development of ICDs. We recruited 17 PD patients with ICDs and 17 without ICDs, matched for several clinical variables, without clinically significant cognitive deficits. Assessments included behavioural scales and a neuropsychological battery, including the Iowa Gambling Task (IGT). In patients with ICDs, the total score of the BIS and the Motor Impulsivity subscore were significantly higher than in patients without ICDs. In patients with ICDs, we observed only statistical trends towards a worse performance on neuropsychological tasks (go-no-go subtest of the Frontal Assessment Battery, oral verb naming task, copying of drawings with landmarks) sensitive to frontal
lobe dysfunction (FLD) and on the IGT (loss of a greater amount of money, more risky choices). As compared to patients without ICDs, they reported a more than threefold number of errors on the interference subtest of Stroop test, which is also sensitive to FLD. Although this study did not show any significant difference between PD patients presenting ICDs as compared with patients without ICDs on neuropsychological variables, some preliminary evidence was detected suggesting a trend toward a worse performance of the PD-ICD group on few neuropsychological tasks which are at least partially sensitive to frontal lobe dysfunction, including tasks sensitive to dysfunction of ventral fronto-striatal loops
Effects of stimulation of the subthalamic nucleus on naming and reading nouns and verbs in Parkinson's disease
No full textAn impairment for verbs has been described in patients with Parkinson's disease (PD), suggesting that a disruption of frontal-subcortical circuits may result in dysfunction of the neural systems involved in action-verb processing. A previous study suggested that deep brain stimulation (DBS) of the subthalamic nucleus (STN) during verb generation may affect the ability to select from many competing lexical alternatives. In this study, 12 PD patients who had undergone bilateral STN DBS and completed an 8-year follow-up and 14 matched normal controls were administered action and object naming tasks and verb and noun reading tasks. Their responses were recorded using a microphone, resulting in a signal that marked the onset of the verbal response and allowed to measure response times (RTs). Accuracy was scored manually. RESULTS: Overall performance in naming (independently of stimulation): In naming task controls were faster and more accurate than PD patients. In both groups, performance (accuracy and RTs) was worse on action naming than object naming. PD patients were significantly slower than controls in naming actions. Effect of stimulation: Compared with the OFF stimulation condition, in ON stimulation condition PD patients showed improved performance on object and action naming tasks (increased accuracy, faster RTs), with a decreased number of semantic errors. Some evidence also emerged that action naming in the ON stimulation condition improved more than object naming. On noun and verb reading tasks, although accuracy was at ceiling in both groups and no significant difference was observed in RTs for nouns and verbs, PD patients were slower than controls. CONCLUSIONS: Our findings suggest that STN DBS may improve lexical search in PD patients. We hypothesize that STN stimulation may facilitate the motor components involved in naming and reading tasks (increased speed of speech onset), resulting in shorter RTs in both naming and reading and, to some extent, in increased accuracy in naming due to fewer omissions (no response within the 7500ms time limit). However, to account for greater accuracy in naming due to decreased number of semantic errors in the ON stimulation condition, we hypothesize that STN stimulation restores the activity of the corticostriatal circuits involved in selection processes of a target word among different alternatives
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Verbal list learning and memory profiles in HIV-infected adults, Alzheimer's disease, and Parkinson's disease: An evaluation of the "cortical hypothesis" of NeuroAIDS.
No full textHIV+ population is getting older because of progress in treatments. Yet, there are concerns that Older HIV+ individuals (OHIV+) may be more vulnerable for developing a "cortical" dementia such as Alzheimer Disease (AD). Our aim was to explore the hypothesis that the cognitive deficit extends to ''cortical'' functions in OHIV+ by comparing serial position effects (SPE) in different groups of participants affected by "cortical" or "subcortical" damage. We enrolled a total of 122 subjects: 22 OHIV+ (≥60 years of age), 31 Younger HIV+ (YHIV+) (<60 years of age), 18 participants with AD, 23 subjects with Parkinson Disease (PD), and 28 healthy subjects. All subjects performed verbal learning tasks (VLT) to explore SPE. Factorial analysis of covariance showed a significant effect of "group" (p < 0.001) and "task" (Primacy vs Recency) (p < 0.001), but no significant group*task (p = 0.257) interaction. Compared with healthy subjects (p = 0.003), AD had the most severe reduction of Primacy, confirming a primary "encoding deficit," while PD confirmed a "frontal pattern." OHIV+ showed a memory profile similar to that of PD with a worsening of the cognitive performance in comparison with YHIV+. In conclusion, we did not confirm the "cortical" hypothesis in OHIV+, at least in terms of learning and memory functions
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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