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Biomedical subjects

S Della Sala

Publications and source records attributed to S Della Sala.

At least 19 recordsLinked to original sources
PubMed2003

How many camels are there in Italy? Cognitive estimates standardised on the Italian population.

OBJECTIVE: We provided the standardisation of a new Cognitive Estimation Task (CET). PARTICIPANTS: the test was administered to 175 healthy subjects. RESULTS: performance on the Cognitive Estimation Task (CET) is associated with gender (where women show poorer performance than men) and education (where more highly educated individuals show better performance compared to individuals with lower levels of education). However,CET performance is not associated with age. DISCUSSION: the lack of age effects on the CET may be explained by the task dependence on "crystallised intelligence", which is less affected by healthy adult ageing than "fluid intelligence".

Adolescent↗
PubMed2002

Gait apraxia after bilateral supplementary motor area lesion.

OBJECTIVES: The study aimed at addressing the issue of the precise nature of gait apraxia and the cerebral dysfunction responsible for it. METHODS: The case of a patient, affected by a bilateral infarction limited to a portion of the anterior cerebral artery territory is reported. The patient's ability to walk was formally assessed by means of a new standardised test. RESULTS: Due to an anomaly within the anterior cerebral artery system, the patient's lesion was centred on the supplementary motor regions of both hemispheres. He presented with clear signs of gait apraxia that could not be accounted for by paresis or other neurological deficits. No signs of any other form of apraxia were detected. CONCLUSIONS: The clinical profile of the patient and the analysis of 49 cases from previous literature suggest that gait apraxia should be considered a clinical entity in its own right and lesions to the supplementary motor areas are responsible for it.

Apraxias↗
PubMed2002

Object recognition and object orientation in Alzheimer's disease.

There are a wide variety of neuropsychological deficits in Alzheimer's disease (AD), among which are disorders of visual perception and spatial cognition. The present study investigated the ability of 20 mildly to moderately deteriorated patients with AD (and 174 age- and education-matched controls) on tasks that required them to visually identify, provide the canonical orientation of, and mentally rotate common objects. Some 85% of the AD patients performed poorly on all tasks. The authors were able to identify a small number of individual patients whose pattern of performance represented double dissociations between recognizing objects and knowing their canonical orientation. These findings are interpreted in the context of previous findings, especially as to whether information relating to an object's orientation and identity is independently coded.

Adult↗
PubMed2001

Memory-driven movements in limb apraxia: is there evidence for impaired communication between the dorsal and the ventral streams?

Memory-driven reaching and grasping movements were analysed in patients with left cerebral hemispheric damage and impaired gesture imitation. The dorsal and ventral streams of the visual pathway model of Milner and Goodale (Milner and Goodale, The Visual Brain in Action, 1995) are thought to operate relatively independently. However, cross-connections between the areas of each pathway are likely to enable interactions essential for higher-level praxis. Apraxic errors such as seen in gesture imitation can possibly be understood as arising from a disconnection of the two visual pathways. If the integrated action of the perceptual and visuomotor systems in patients with apraxia is compromised, then we would expect to find indications of impaired motor programming and misreaching in these patients when making movements driven by stored representations. Such a pattern, however, was not found in our sample of apraxic patients. Patients with limb apraxia produced normal movement kinematics and normal end-point accuracy when making memory-driven reaching movements with or without visual guidance of movement. Furthermore, perceptual information about object size and object distance were incorporated as normal in memory-driven grasping movements of these patients.

Aged↗
PubMed2000

Cognition in action: testing a model of limb apraxia.

Assessment of limb apraxia is still suffering from Liepmann's legacy and performance in gesture-processing tests is generally rendered by classifying patients' profile according to the classic clinical labels of ideomotor and ideational apraxia. At odds with other cognitive functions, interpretation of apraxia has suffered from a lack of a reliable model which does justice to its complexity. Recently such a model has been proposed (Rothi et al., 1991, 1997). In this article a modified version of this model is presented and predictions are made according to its functional architecture. Five different patterns of impairment of gesture processing are postulated. To validate the predicted performance profiles, 19 left-hemisphere-damaged patients were assessed by means of an ad hoc battery of four praxis tests. Four of the five predicted apraxia patterns were observed, the fifth being more equivocal. These results support the need to overcome the simplistic dichotomous view of apraxia and confirm the fruitfulness of a model of normal gesture processing in order to understand dissociations in apraxia.

Aged↗
PubMed2000

Perceiving left and imagining right: dissociation in neglect.

Signor Piazza, a patient with a left parieto-occipital haemorrhage and a right thalamic stroke, showed severe right personal neglect (e.g. touching own body parts) and right perceptual neglect in tasks with (e.g. cancelling tasks) or without (e.g. description of a complex picture) motor response. He had also right-sided neglect dyslexia (including single words), without language impairments. However, the patient also presented with a clear left-sided deficit in the representational domain (e.g. imagery tasks). Signor Piazza's pattern of performance suggests dissociation between imagery and perception within the neglect syndrome.

Aged↗
PubMed2000

Nurturing syndrome: a form of pathological bereavement with delusions in Alzheimer's disease.

We report the history and neuroimaging profile of two patients, CS and KC who developed an unusual bereavement reaction with delusions following the deaths of their husbands. Their neuropsychological profiles met criteria for dementia of Alzheimer type. The delusions about their husbands' existence were persistent despite a considerable passage of time after their deaths. SPECT investigation showed reduction of blood flow in the frontal area in both patients when compared with demented controls and in particular a significant reduction in perfusion was observed in the right frontal regions. We argue that this significant reduction of blood flow in the right frontal area, in the context of severe cognitive deterioration, might be responsible for their delusional reaction to bereavement which we interpret as result of reality monitoring and episodic memory failure.

Aged↗
PubMed2000

Intrusion errors in numerical transcoding by Alzheimer patients.

The errors made by brain-damaged patients when they attempt numerical transcoding tasks have recently been considered as a possible aid to early diagnosis of the disease. The transcoding errors of 20 Alzheimer's disease patients are described, and the incidence of each kind of error compared with norms from healthy subjects. Tegnér and Nybäck (Tegnér R, Nybäck H. "To hundred and twenty4our": a study of transcoding in dementia. Acta Neurologica Scandinavia 1990; 81: 177-178) reported that Alzheimer patients often express numerical information in a mixture of verbal and digital codes and Kessler and Kalbe (Kessler J, Kalbe E. Written numerical transcoding in patients with Alzheimer's disease. Cortex 1996; 32: 755-761) suggested that such intrusions of the source code into the target code may not only be largely absent from the responses of the healthy population, but also from the transcoding operations of patients with other kinds of brain damage, such as aphasia. It was found that intrusion errors occurred much more frequently in the transcoding protocols of some of the Alzheimer patients than they do in those of healthy subjects. On the other hand, they were entirely absent from the protocols of other Alzheimer patients. The implications of the findings for the early diagnosis of Alzheimer's disease are discussed, and the phenomenon of intrusion errors is considered in terms of some of the models of arithmetical processing that have been proposed.

Aged↗
PubMed2000

Prospective and retrospective memory in normal ageing and dementia: a questionnaire study.

Frequency of prospective memory and retrospective memory failures was rated on a 16-item questionnaire by 862 volunteers, from five groups: patients with Alzheimer Disease (rated by carers), carers of Alzheimer Disease patients, elderly, young, and a group of married couples. Reported memory failures were highest for Alzheimer Disease patients, and lowest for carers, with elderly and young controls in between. More prospective memory than retrospective memory failures were reported in all groups, although the difference was small for Alzheimer Disease patients who were rated near ceiling for both. Prospective memory failures of Alzheimer Disease patients were reported as more frustrating for carers than retrospective memory failures; prospective memory and retrospective memory failures frustrated Alzheimer Disease patients equally. Data from the couples indicated that there were no biases resulting from rating on behalf of someone else. These results suggest that: (1) normal ageing has no greater effect on self-reported retrospective memory than prospective memory failures, (2) the relatively small number of memory failures reported by carers may result from comparing themselves with the Alzheimer Disease patients in their care, and (3) prospective memory failures have a greater impact on the lives of the carers and are therefore more likely to be reported as early indicants of the disease.

Adolescent↗
PubMed2000

Visual similarity effects in immediate verbal serial recall.

The role of visual working memory in temporary serial retention of verbal information was examined in four experiments on immediate serial recall of words that varied in visual similarity and letters that varied in the visual consistency between upper and lower case. Experiments 1 and 2 involved words that were either visually similar (e.g. fly, cry, dry; hew, new, few) or were visually distinct (e.g. guy, sigh, lie; who, blue, ewe). Experiments 3 and 4 involved serial recall of both letter and case from sequences of letters chosen such that the upper- and lower-case versions were visually similar, for example Kk, Cc, Zz, Ww, or were visually dissimilar, for example Dd, Hh, Rr, Qq. Hence in the latter set, case information was encoded in terms of both the shape and the size of the letters. With both words and letters, the visually similar items resulted in poorer recall both with and without concurrent articulatory suppression. This visual similarity effect was robust and was replicated across the four experiments. The effect was not restricted to any particular serial position and was particularly salient in the recall of letter case. These data suggest the presence of a visual code for retention of visually presented verbal sequences in addition to a phonological code, and they are consistent with the use of a visual temporary memory, or visual "cache", in verbal serial recall tasks.

Adult↗
PubMed2000

Lung cancer risk in Venice: a population-based case-control study.

Populations resident in the historical town of Venice and in the inland industrial city of Mestre are at different risk of exposure to environmental pollutants. This case-control study compares the risk of developing lung cancer in the two populations in relation to known risk factors for this neoplasm. A retrospective study of 305 incident cases of lung and 447 frequency-matched population controls was conducted through a standard questionnaire on main risk factors for lung cancer. Completeness of cases was checked against the Venetian Cancer Registry files. The results indicate that lung cancer risk associated with tobacco smoking was high in both areas, although more elevated in Venice islands among heavy smokers. An elevation of risk was associated with housing without a heating system, possibly suggesting a role of worse hygienic conditions. An increased risk associated with exposure to occupational carcinogens was detected in the inland area. In conclusion, lung cancer risk due to tobacco smoking largely affects both the populations, while other risks such as occupation or housing conditions appear to be more population-specific.

Adult↗
PubMed1999

Working memory and vigilance: evidence from normal aging and Alzheimer's disease.

Both single unit recording and neuroradiological studies suggest that frontal and executive processes are necessary for visual maintenance rehearsal. This observation is linked to the classic vigilance literature by the proposal that vigilance decrement is found when the subject is required to maintain a representation over a brief delay. Vigilance performance was therefore studied in a sample of elderly subjects who were tested over a 40-min period involving perceptual or memory-based tasks which were matched for initial level of performance. There was a significant interaction between task and delay, with only the memory-based task showing decrement. A second study used the same two tasks to investigate vigilance performance in patients suffering from probable Alzheimer's Disease. Over a 15-min delay period, an equivalent interaction effect occurred, again indicating substantially greater decrement for the memory-based task. The results are interpreted as consistent with a role for the executive processes of working memory in both visual rehearsal and vigilance performance.

Aged↗
PubMed1999

Neglect without extinction.

A patient, AB, is reported who showed clear signs of neglect but no extinction (N+ E-). Several hypotheses proposed to account for this dissociation were put to the test. The postulated association between motor neglect and extinction did not hold good, nor did the possibility that the N+ E- dissociation may be traced back to the difference in test requirements and therefore observed only in patients with object-centred neglect. Likewise, manipulating the physical features of the stimuli (relative size, exposure time, presentation synchrony) did not elicit extinction. However, when the task demands were modified by asking the patient to perform a further spatial analysis of the stimuli, rather than simply detect them, extinction emerged. Since AB performed well on several neglect tasks requiring parallel processing, while failing all tasks calling for serial processing, the hypothesis is put forward that AB's N+ E- dissociation could be interpreted within the parallel/serial distinction framework.

Aged↗