Visual short-term store can compensate for a defective phonological short-term store in patients with apraxia of speech

OBJECTIVE: 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

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

"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

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.

HIV+ 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

Posterior AD-type pathology: cognitive subtypes emerging from a cluster analysis

"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

Neuropsychological features of patients with Parkinson’s disease and impulse control disorders

Impulse 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

Antiretroviral neuropenetration scores better correlate with cognitive performance of HIV-infected patients after accounting for drug susceptibility

The aim of the study was to explore how viral resistance and antiretroviral central nervous system (CNS) penetration could impact on cognitive performance of HIV-infected patients

Cardiovascular risk factors and carotid intima-media thickness are associated with lower cognitive performance in HIV-infected patients

OBJECTIVES: The aim of the study was to investigate the relationship between metabolic comorbidities, cardiovascular risk factors or common carotid intima-media thickness (cIMT) and cognitive performance in HIV-infected patients. METHODS: Asymptomatic HIV-infected subjects were consecutively enrolled during routine out-patient visits at two clinical centres. All patients underwent an extensive neuropsychological battery and assessment of metabolic comorbidities and cardiovascular risk factors. Moreover, cIMT was assessed by ultrasonography. Cognitive performance was evaluated by calculating a global cognitive impairment (GCI) score obtained by summing scores assigned to each test (0 if normal and 1 if pathological). RESULTS: A total of 245 patients (median age 46 years; 84.1% with HIV RNA < 50 copies/mL; median CD4 count 527 cells/μL) were enrolled in the study. Cardiovascular risk factors were highly prevalent in our population: the most frequent were dyslipidaemia (61.2%), cigarette smoking (54.3%) and hypertension (15.1%). cIMT was abnormal (≥ 0.9mm) in 31.8% of patients. Overall, the median GCI score was 2 [interquartile range (IQR) 1-4]; it was higher in patients with diabetes (P = 0.004), hypertension (P = 0.030) or cIMT ≥ 0.9 mm (P < 0.001). In multivariate analysis, it was confirmed that diabetes (P = 0.007) and cIMT ≥ 0.9 mm (P = 0.044) had an independent association with lower cognitive performance. In an analysis of patients on combination antiretroviral therapy (cART), abacavir use was independently associated with a better cognitive performance (P = 0.011), while no association was observed for other drugs or neuroeffectiveness score. CONCLUSIONS: Diabetes, cardiovascular risk factors and cIMT showed a strong association with lower cognitive performance, suggesting that metabolic comorbidities could play a relevant role in the pathogenesis of HIV-associated neurocognitive disorders in the recent cART era

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

<p>HIV+ 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” (<i>p</i> < 0.001) and “task” (Primacy vs Recency) (<i>p</i> < 0.001), but no significant group*task (<i>p</i> = 0.257) interaction. Compared with healthy subjects (<i>p</i> = 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.</p