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Annalena Venneri

Publications and source records attributed to Annalena Venneri.

At least 19 recordsLinked to original sources
PubMed2005

The age of acquisition of words produced in a semantic fluency task can reliably differentiate normal from pathological age related cognitive decline.

This study examined differences in the characteristics of words produced by healthy elderly controls and by patients with Alzheimer's disease (AD) in a semantic fluency task (generating words from the categories of animals and fruit). Ninety-six AD patients (MMSE 13-29) and 40 controls matched for age and socio-cultural background completed a semantic fluency task. Length, frequency, typicality and age of acquisition (AoA) values were obtained for each word generated. In comparison with controls, AD patients generated fewer items, and their items were higher in frequency, shorter in length, more typical and earlier in AoA. Discriminant function analysis showed that AoA was the best predictor of group membership (patient/control). The mean AoA of words generated correctly classified 95% of controls and 88% of patients.

Age of Onset↗
PubMed2005

Empirical evidence of neuroprotection by dual cholinesterase inhibition in Alzheimer's disease.

Brain grey matter density changes were quantified using voxel based morphometry in 26 patients with minimal to mild Alzheimer's disease (AD) treated with three cholinesterase inhibitors over 20 weeks. Patients whose drug treatment also inhibited butyrylcholinesterase did not show the widespread cortical atrophic changes in parietotemporal regions invariably reported in untreated AD patients, and which were detectable in the subgroups treated with selective acetylcholinesterase inhibition. This finding is the first empirical evidence that dual cholinesterase inhibition may have neuroprotective potential in AD.

Aged↗
PubMed2005

Different neuronal pathways support the generation of general and specific mental images.

The aim of this functional magnetic resonance imaging (fMRI) study was to investigate the neural correlates associated with the generation of general (i.e., prototypical) and specific (i.e., exemplar) visual mental images from concrete nouns. The fMRI paradigm included a non-imagery baseline, and two activation conditions requiring the generation of either general or specific images. Image generation times and brain activation were recorded. Analysis of the behavioral results showed that generating general images took less than the specific ones. The comparison of each activation condition with the baseline showed significant increase in brain activation in left frontal areas in both kinds of images, with the additional involvement of the posterior cingulate cortex during the generation of specific images. When the two activation conditions were contrasted with each other and masked for their respective comparison with baseline, significant activation was found in right frontal areas for general mental images, whereas a significant increase in activation in the left superior frontal region and the right thalamus was detected during the generation of specific mental images. These findings suggest that general and specific mental images are generated with the support of two different neural pathways. The generation of general images seems to involve brain areas associated with the formation of global gestalt-like images (areas in the right hemisphere), while the generation of specific mental images appears to require additional support from areas involved in the retrieval of visual details (i.e., the right thalamus).

Adult↗
PubMed2004

The evolution of dysgraphia in Alzheimer's disease.

Evidence from recent studies suggests that writing may be an aspect of cognition capable of identifying impairments specific to patients with Alzheimer's Disease (AD). The precise nature and progression of the writing disorder, however, remains unclear. The current study assessed the central and peripheral aspects of writing among a sample of minimal, mild and moderate AD patients and a group of healthy elderly controls on a narrative description task. Comparisons of the two groups indicated that AD patients suffer from a primary impairment at the semantic level. Even those in the minimal stages of the disease could be differentiated from controls on measures of word finding and information conveyed. This semantic impairment was coupled with a secondary milder impairment in phonological processing. The prevalence of phonological errors increased, but no shift in error type (plausible/implausible) was identified as the disease progressed. In addition to the central impairments, patients evinced damage at the peripheral level. In the more severe stages, patients experienced more problems with letter formation and stroke placement and tended to rely upon the more simplistic writing form of print. The writing impairment in AD is multi-componential in nature and follows the pattern of cortical deterioration reported in the brains of AD patients.

Aged↗
PubMed2004

Belief and awareness: reflections on a case of persistent anosognosia.

Persisting anosognosia after acute lesions is relatively rare, and no case studies to date have reported functional scanning investigation of this disorder. This is a case report of an 85-year-old right-handed Scottish woman, EN, who showed persistent anosognosia for hemiplegia following a haemorrhagic stroke. Extensive damage in the right hemisphere caused left upper and lower limb flaccid hemiplegia and severe left-sided neglect. Lack of awareness for her deficits was still present 2 years after the stroke, when neurological, neuropsychological, and SPECT examinations were performed. Testing revealed severe left unilateral neglect and poor performance on verbal fluency tasks. EN had age normal memory performance, and her object recognition and praxic abilities were preserved. She showed no global reasoning or language problems apart from her abnormal beliefs. EN believed that she was able to walk and carry out several activities, in a context of other disorders of belief. SPECT scan showed marked hypoperfusion in the right parietotemporal cortex and this extended to the associative cortex in the right frontal regions. The persistence of anosognosia in this patient cannot be explained by memory impairments or global cognitive decline. A possible account might be that alteration in awareness was maintained by contingent right frontal and/or parietal dysfunction causing a suspension or change in the ability to monitor and check the 'real' and especially to assess the veracity of mental contents.

Aged↗
PubMed2004

Modified Card Sorting Test: normative data.

The Modified Card Sorting Test (MCST), a shortened version of the Wisconsin Card Sorting Test, proposed by Nelson in 1976 is a neuropsychological test that is widely used in clinical settings for the evaluation of executive functions in patients with focal, traumatic and degenerative brain diseases. Despite its frequent use, normative data for the MCST are scant. The aim of this study was to collect normative data for the MCST on a sample including 248 healthy individuals ranging from 20 to 90 years of age and equally distributed for education level and sex (124 males and 124 females). Performance on the MCST was scored by computing the number of categories achieved by a participant, and the number of perseverative errors. Multiple regression analyses revealed a significant effect of age and education on the number of categories and perseverative errors but no effect of sex. Cut-off scores were then determined and equivalent scores computed for both the number of categories and the perseverative errors. The availability of normative data for the MCST will be very valuable in clinical settings for testing patients with focal, traumatic and degenerative brain diseases. The use of reference norms will permit a better characterisation of a patient's impaired and spared abilities.

Adult↗
PubMed2003

A case for case: handling letter case selection in written spelling.

This study reports the unusual writing performance of a 72-year-old woman, Pp, who was unable to maintain her writing within a particular case, and made numerous case mixing errors (e.g. insTEAd). Her oral spelling was flawless, but when tested using a written spelling task (including words and non-words), a picture description task, a sentence writing task and a transcription task (from upper case to lower case, and vice versa), she showed a high proportion of case mixing errors, though spelling per se was correct. The problem, although less severe, was also present when spelling with letter cards. Despite a spared ability to select the correct letters in the stimulus, specify the correct number of letters and place them in the correct order, she had a specific problem in selecting the appropriate case. This impairment is indicative of peripheral dysgraphia. She appeared to have intact orthographic representations, but selection of the appropriate allographic codes for upper and lower case was impaired. Her longitudinal neuropsychological profile and MRI evidence suggest that Pp suffers from mild vascular dementia with more severe impairments in attentional functions. Her writing deficits may be accounted for by a model that incorporates an inhibitory mechanism, which is responsible for maintaining the appropriate case and inhibiting the inappropriate one, subsequent to case selection in writing. Failure of this mechanism would explain the pattern of case mixing shown by Pp.

Aged↗
PubMed2003

Brain activation and the phonological loop: the impact of rehearsal.

Brain activation studies offer valuable techniques for exploring human cognition to complement behavioral measures and several studies report a wide range of neuroanatomical networks activated during verbal immediate memory. Behavioral investigations have shown use of multiple cognitive strategies across and within individuals, although aggregate data appear to reflect a common cognitive function. Variation in cognitive strategies could result in aggregate activation patterns that are relatively widespread and difficult to interpret. Imaging data (fMRI) from six participants instructed to use subvocal rehearsal showed significant left hemisphere activation in the inferior parietal gyrus and inferior and middle frontal gyri, a pattern of activation more clearly focused than in previous brain activation studies of immediate verbal serial ordered recall. Our results should be relatively free of the influence of other mental operations, and emphasise the importance of considering which cognitive strategies might give rise to focused or to diverse patterns of brain activation.

Adult↗
PubMed2003

Intra-individual measures of association in neuropsychology: inferential methods for comparing a single case with a control or normative sample.

Performance on some neuropsychological tests is best expressed as an intra-individual measure of association (such as a parametric or non-parametric correlation coefficient or the slope of a regression line). Examples of the use of intra-individual measures of association (IIMAs) include the quantification of performance on tests designed to assess temporal order memory or the accuracy of time estimation. The present paper presents methods for comparing a patient's performance with a control or normative sample when performance is expressed as an IIMA. The methods test if there is a significant difference between a patient's IIMA and those obtained from controls, yield an estimate of the abnormality of the patient's IIMA, and provide confidence limits on the level of abnormality. The methods can be used with normative or control samples of any size and will therefore be of particular relevance to single-case researchers. A method for comparing the difference between a patient's scores on two measures with the differences observed in controls is also described (one or both measures can be IIMAs). All the methods require only summary statistics (rather than the raw data from the normative or control sample); it is hoped that this feature will encourage the development of norms for tasks that use IIMAs to quantify performance. Worked examples of the statistical methods are provided using data from a clinical case and controls. A computer program (for PCs) that implements the methods is described and made available.

Adult↗
PubMed2003

Arithmetic difficulties in children with visuospatial learning disability (VLD).

Eighteen children with visuospatial learning disability (VLD) were compared to normal control children on a series of numerical and calculation tasks. Oral and written (dictated) calculation was assessed and operations differed not only in terms of the type of number processing requirements but also in terms of their visuospatial demand. The aim was to disentangle errors due to visuospatial processing failure from those deriving from incorrect knowledge of calculation procedures. Results showed that all children had relatively good knowledge of numerical facts and there was no statistical difference between the groups. No group difference was found in the overall performance in oral calculation, but a significant difference was present when the children were required to complete the operations in writing, with the VLD group achieving poorer performance than the controls. Furthermore, VLD children had greater difficulties when operations required borrowing or carrying; this was particularly problematic in subtractions. The results indicate that VLD children do not have a generalised problem with calculation per se or number manipulation in general. Rather their problems concern dealing with some processes that govern calculation especially those loading on visuospatial abilities.

Analysis of Variance↗
PubMed2003

Upper and lower face and ideomotor apraxia in patients with Alzheimer's disease.

INTRODUCTION: Apraxia of face movement in Alzheimer's disease (AD) has been rarely investigated. This study aimed at investigating the frequency of lower (mouth, tongue and throat) and upper (eyes and eyebrows) face apraxia, in AD and its relationship with limb apraxia and severity of dementia. METHODS: Fifty seven patients with AD were tested with a new standardised test of face apraxia including upper and lower face movements, which uses an item-difficulty weighted scoring procedure, the IMA test, a test of ideomotor apraxia and the M.O.D.A., a means to assess dementia severity. RESULTS: Thirteen (23%) and 19 (33%) participants were below cut-off respectively on the upper and lower face apraxia test. Both sections of the Face Apraxia Test correlated significantly with the Ideomotor Apraxia Test. However, double dissociations between different types of apraxia were observed. Both the upper and lower face apraxia tests correlated significantly with the measure of dementia severity. CONCLUSIONS: The finding show that a proportion of AD patients fails face apraxia tests. Their face apraxia is interlinked with ideomotor limb apraxia, although dissociations are possible. Severity of dementia deterioration accounts for a good proportion of the variability of AD patients' performance on face apraxia tests.

Aged↗
PubMed2003

A preliminary study of the cognitive mechanisms supporting time estimation.

Evidence from neuropsychological studies has suggested that verbal and visuospatial abilities might be differentially involved in time perception and that, because there is specialised competence, the two brain hemispheres might play different roles in time-keeping mechanisms. Reported are results of three experiments in which the time estimates of normal adults were tested using a prospective paradigm while they were engaged in concurrent secondary tasks requiring visuospatial or verbal memory and attention. Analysis showed no convincing evidence in support of a differential role of either verbal or visuospatial abilities in time estimation. The greatest disruption in time accuracy was detected when participants performed the time estimation tasks concurrently with secondary working memory tasks. These findings emphasize the importance of the involvement of specific cognitive systems rather than cognitive domains in the processing of temporal information.

Adult↗