The Free Association Task: Proposal of a Clinical Tool for Detecting Differential Profiles of Semantic Impairment in Semantic Dementia and Alzheimer's Disease.

: It is widely agreed that patients suffering from Alzheimer's disease (AD) and patients suffering from semantic dementia (SD) might fail clinically administered semantic tasks due to a different combination of underlying cognitive deficits: namely, degraded semantic representations in SD and degraded representations plus executive control deficit in AD. However, no easy administrable test or test battery for differentiating the semantic impairment profile in these populations has been devised yet. : In this study, we propose a new easy administrable task based on a free association procedure (F-Assoc) to be used in conjunction with category fluency (Cat-Fl) and letter fluency (Lett-Fl) for quantifying pure representational and pure control deficits, thus teasing apart the semantic profile of SD and AD patients.

Implicit prototype learning in patients with memory deficit: Evidence from a study with Alzheimer's disease patients.

Objective: In a previous study (Zannino et al., 2012), it was demonstrated that individuals with amnestic mild cognitive impairment (MCI) were unimpaired on a new prototype learning task consisting of morphed faces (face prototype learning task [FPLT]). This paradigm was devised to improve on the classical dot pattern task by ruling out any reliance on residual episodic memory or working memory resources.

Articulatory suppression delays processing of abstract words: The role of inner speech.

Compared to concrete concepts, like "book," abstract concepts expressed by words like "justice" are more detached from sensorial experiences, even though they are also grounded in sensorial modalities. Abstract concepts lack a single object as referent and are characterised by higher variability both within and across participants. According to the Word as Social Tool (WAT) proposal, owing to their complexity, abstract concepts need to be processed with the help of inner language.

Visuo-verbal distinction revisited: new insights from a study on temporal lobe epilepsy patients in the debate over the lateralization of material-specific and process-specific aspects of memory.

: The automatic interaction between a cue and a memory trace can give rise to the vivid recollection of a purely sensory past experience. But are humans able to reach back intentionally to purely sensory experiences in the absence of any exogenous or endogenous cue? In the present study, we propose an alternative hypothesis, claiming that the retrieval of associated semantic memories, stored in the left hemisphere and acting as endogenous cues, is a prerequisite for intentionally recollecting sensory experience stored in the right hemisphere during mental time travels (MTT). : To investigate this issue, we administered an MTT task to 26 epileptic patients (16 males and 10 females) who had undergone right or left temporal lobectomy and to 28 age and education matched controls.

The attribute priming effect in patients with Alzheimer's disease.

Experiments with semantic priming (SP) paradigms have documented early hypopriming in patients with AD when concepts are used as primes and attribute concept features as targets, suggesting that concept attributes are vulnerable to damage very early in the disease course. The aims of this study were to confirm early priming reduction in the attribute condition in patients with AD and to determine which of several semantic indexes (such as the level of distinctiveness, correlation or feature dominance of concept features) best predicts the priming effect size in AD. We administered an SP attribute condition paradigm to 20 mildly demented patients with AD and to 10 NCs.

Associative Agreement as a Predictor of Naming Ability in Alzheimer's Disease: A Case for the Semantic Nature of Associative Links.

We aimed to address the long-standing issue of the nature of the relationships that link a cue word to words associated with it. In keeping with a recently proposed neuropsychological model of semantic memory (Zannino et al., 2015), we provide support for the hypothesis that associative links are semantic in nature and not lexical.

Exploring classical conditioning for strengthening the links between semantic and lexical representations in pure anomia: Preliminary findings from a single case study.

The same language symptom might arise at different functional loci in people with aphasia. Therefore, it is plausible that different therapeutic interventions should be adopted to approach the same difficulties in different patients. Although this point of view is still widely accepted, recently the focus has shifted from the functional locus of a rehabilitative intervention to the mechanisms of action underlying the relearning process.

The contribution of neurodegenerative diseases to the modelling of semantic memory: A new proposal and a review of the literature.

This paper provides a focused review of the literature on semantic impairment in semantic dementia (SD) and Alzheimer's disease (AD). An attempt is made to interpret the most relevant phenomena in the light of a new model of semantic memory. This model comprises a language-based component (disrupted in SD and AD), which supports our ability to establish reliable token vs.

Semantic similarity between old and new items produces false alarms in recognition memory.

In everyday life, human beings can report memories of past events that did not occur or that occurred differently from the way they remember them because memory is an imperfect process of reconstruction and is prone to distortion and errors. In this recognition study using word stimuli, we investigated whether a specific operationalization of semantic similarity among concepts can modulate false memories while controlling for the possible effect of associative strength and word co-occurrence in an old-new recognition task. The semantic similarity value of each new concept was calculated as the mean cosine similarity between pairs of vectors representing that new concept and each old concept belonging to the same semantic category.

The special status of verbal knowledge in semantic memory: evidence from performance of semantically impaired subjects on verbalizable and non-verbalizable versions of the object decision task.

According to the semantic hub hypothesis, a supramodal semantic hub is equally needed to deal with verbal and extraverbal "surface" representations. Damage to the supramodal hub is thought to underlie the crossmodal impairment observed in selective semantic deficits. In the present paper, we provide evidence supporting an alternative view: we hold that semantic impairment is not equal across domains but affects verbal behavior disproportionately.

Letters persistence after physical offset: visual word form area and left planum temporale. An fMRI study.

Iconic memory is a high-capacity low-duration visual memory store that allows the persistence of a visual stimulus after its offset. The categorical nature of this store has been extensively debated. This study provides functional magnetic resonance imaging evidence for brain regions underlying the persistence of postcategorical representations of visual stimuli.

Performing prototype distortion tasks requires no contribution from the explicit memory systems: evidence from amnesic MCI patients in a new experimental paradigm.

Evidence shows that amnesic patients are able to categorize new exemplars drawn from the same prototype as in previously encountered items. It is still unclear, however, whether this ability is due to a spared implicit learning system or residual explicit memory and/or working memory resources. In this study, we used a new paradigm devised expressly to rule out any possible contribution of episodic and working memory in performing a prototype distortion task.

Alzheimer's disease and semantic deficits: a feature-listing study.

Objective: The aim of the present study was to investigate the qualitative characteristics of semantic impairment in patients with mild to moderate Alzheimer's disease (AD). In particular, we wanted to verify if subordinate and distinctive concept features are affected earlier than superordinate or shared ones and whether sensory features are more vulnerable than nonsensory ones. Also, we investigated if feature correlation and level of feature occurrence in concept description (dominance) influence the resilience of concept features to degenerative damage.

Spared structural knowledge in a case of semantic dementia: implications for models of object recognition, semantic memory and structural description.

Most models of visual object recognition assume that items belonging to known categories are represented in long-term memory in terms of both structural descriptions and semantic representations. The former specify the visual appearance of category members and the latter allow recognising them as meaningful objects. Nevertheless, the format of these two kinds of representations and their relationships are still a matter of debate.

Semantic priming for coordinate distant concepts in Alzheimer's disease patients.

Semantic priming paradigms have been used to investigate semantic knowledge in patients with Alzheimer's disease (AD). While priming effects produced by prime-target pairs with associative relatedness reflect processes at both lexical and semantic levels, priming effects produced by words that are semantically related but not associated should reflect only semantic activation processes. This study was aimed at further investigating automatic semantic priming effects in AD patients when semantically related concepts with little to no lexical association are used.

Compound heterozygosity of 2 novel MAPT mutations in frontotemporal dementia.

Intronic MAPT mutations altering exon 10 splicing lead mainly to an increase of 4Rtau. The objective of this study is to report clinical, genetic, and neuropathological data of an apparently sporadic early onset frontotemporal dementia (FTD) case associated with 2 novel intronic MAPT gene mutations IVS10+4A > C and IVS9-15T > C that increase 3Rtau. Methods and subjects used are clinical, neuroradiological, and neuropathological examination; molecular genetics of MAPT, PGRN, and other relevant genes.

The neural correlates of object familiarity and domain specificity in the human visual cortex: an FMRI study.

Ventral occipito-temporal cortex is known to play a major role in visual object recognition. Still unknown is whether object familiarity and semantic domain are critical factors in its functional organization. Most models assume a functional locus where exemplars of familiar categories are represented: the structural description system.

Erosion of telomeric 3'-overhangs in white blood cells of aged subjects with high frequency of very short telomeres.

After extended proliferation, cells enter a state of replicative quiescence that is probably due to progressive telomere shortening. It is supposed that changes in telomere structure eventually expose the chromosome ends to undesired recombination events and thus promote cell senescence. The telomeric 3'-overhang is crucial for efficient chromosome capping, but its specific role in telomere shortening and in triggering the senescence program is uncertain.

Manipulating color and other visual information influences picture naming at different levels of processing: evidence from Alzheimer subjects and normal controls.

There is now a large body of evidence suggesting that color and photographic detail exert an effect on recognition of visually presented familiar objects. However, an unresolved issue is whether these factors act at the visual, the semantic or lexical level of the recognition process. In the present study, we investigated this issue by having Alzheimer's patients and normal controls name figures in four presentation displays (PDs): black and white and colored line drawings, and black and white and color photographs.

Amblyopic dyslexia: a little investigated reading disorder.

We present a case of a little investigated reading disorder we call 'amblyopic dyslexia'. The reading impairment in this patient resulted from a left extrastriate and white matter lesion causing a scotomatic area of partial deficit within the right visual field. The visual deficit was consistent with cerebral amblyopia, that is, reduced form, colour, and light sensitivity without a complete loss of vision.

Telecommunications technology in cognitive rehabilitation.

Cognitive disorders are a common long-term consequence of many forms of acquired neurological damage of different aetiology. The already high prevalence of diseases causing cognitive deficits (in particular stroke) is expected to increase in the near future, leading to a greater need for cognitive rehabilitation. The impact of cognitive impairment on daily functioning may be even greater than that of physical limitations in affected patients, contributing to the high cost of brain disorders.

Visual and semantic processing of living things and artifacts: an FMRI study.

We carried out an fMRI study with a twofold purpose: to investigate the relationship between networks dedicated to semantic and visual processing and to address the issue of whether semantic memory is subserved by a unique network or by different subsystems, according to semantic category or feature type. To achieve our goals, we administered a word-picture matching task, with within-category foils, to 15 healthy subjects during scanning. Semantic distance between the target and the foil and semantic domain of the target-foil pairs were varied orthogonally.

Do confabulators really try to remember when they confabulate? A case report.

Since Korsakoff's (1889/1955) first descriptions of confabulation at the end of the 19th century, all attempts to understand this neuropsychological disorder have focused on memory dysfunctions. Although the precise mechanisms underlying confabulation are still a matter of debate, the prevalent view is that confabulation is the output of a faulty recollective process. In the present paper we raise doubts about this undemonstrated assumption, arguing that confabulators are not necessarily attempting to recall when they confabulate.

Category-specific naming deficit in Alzheimer's disease: the effect of a display by domain interaction.

A category-specific naming effect penalizing living things has often been reported in patients suffering from Alzheimer's disease (AD) and in other brain damaged populations, while the opposite dissociation (i.e., lower accuracy in naming nonliving than living things) is much rarer.

Analysis of the semantic representations of living and nonliving concepts: A normative study.

Current feature-based semantic memory models assume that the semantic representations of concepts differ systematically across living and nonliving categories and that such differences account for the emergence of category-specific semantic deficits in brain-damaged people. To assess some of the different models' main assumptions about structural differences at the semantic feature level in the two major semantic domains, we administrated a feature-listing task to normal young volunteers on 64 concepts drawn from living and nonliving semantic categories. We investigated whether feature correlation, a variable with a crucial role in the emergence of category-specific deficits, should be computed as a concept-dependent or as a concept-independent measure, and we chose the former.