Dual-task paradigm: a means to examine the central executive.
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Aged↗
Biomedical subjects
C Papagno
Publications and source records attributed to C Papagno.
Improvement of left visuo-spatial hemineglect by left-sided transcutaneous electrical stimulation.
The effects of transcutaneous electrical stimulation on left visuo-spatial hemineglect, assessed by a visuo-motor exploratory task (letter cancellation), were investigated in patients with right hemisphere lesions. In Experiment 1 left neck stimulation temporarily improved the deficit in 13 out of 14 patients (93%), while stimulation of the right neck had no positive effects, worsening exploratory performance in nine patients (64%). Experiment 2 showed that left neck stimulation temporarily improved neglect also when head movements were prevented by a chin-rest. In Experiment 3, stimulation of both the left hand and left neck had comparable positive effects on visuo-spatial hemineglect. These results are interpreted in terms of: (1) non-specific activation of the right hemisphere, contralateral to the stimulation side; (2) specific directional effects of left somatosensory stimulation on the egocentric co-ordinates of extra-personal space, which in neglect patients are distorted towards the side of the brain lesion.
Adult↗
Transient left-sided alien hand with callosal and unilateral fronto-mesial damage: a case study.
A patient who showed a transient left alien hand after a subarachnoid haemorrhage, due to a ruptured aneurysm of the anterior communicating artery, is described. No left agraphia and left apraxia could be found. A CT-scan including coronal sections showed a right medial frontal hypodensity and different ischaemic lesions in the anterior part of the corpus callosum. The possible anatomic site of the lesion responsible for the permanent form of alien hand is discussed.
Adult↗
Vestibular stimulation, spatial hemineglect and dysphasia, selective effects.
The selectivity of the effects of vestibular stimulation was investigated in a left brain-damaged patient suffering from right visuo-spatial hemineglect and severe dysplasia. Vestibular stimulation temporarily improved the former but not the latter disorder. These results support the view that this treatment improves hemineglect by a specific effect, running counter the rightward distortion of egocentric co-ordinates, rather than by a general hemispheric activation.
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Verbal short-term memory and vocabulary learning in polyglots.
Polyglot and non-polyglot Italian subjects were given tests assessing verbal (phonological) and visuo-spatial short-term and long-term memory, general intelligence, and vocabulary knowledge in their native language. Polyglots had a superior level of performance in verbal short-term memory tasks (auditory digit span and nonword repetition) and in a paired-associate learning test, which assessed the subjects' ability to acquire new (Russian) words. By contrast, the two groups had comparable performance levels in tasks assessing general intelligence, visuo-spatial short-term memory and learning, and paired-associate learning of Italian words. These findings, which are in line with neuropsychological and developmental evidence, as well as with data from normal subjects, suggest a close relationship between the capacity of phonological memory and the acquisition of foreign languages.
Adult↗
Memory for context but not for content: a neuropsychological follow up.
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Preserved vocabulary acquisition in Down's syndrome: the role of phonological short-term memory.
We report the study of a 23-year-old Italian girl, FF, with Down's syndrome (trisomy 21). FF showed a remarkably good developmental acquisition of Italian language and vocabulary and was able to learn English and French, although the latter with less proficiency. FF showed an entirely preserved function of the phonological short-term store and articulatory rehearsal components of verbal short-term memory. By contrast, she was impaired in a wide range of tasks assessing verbal and non-verbal reasoning, visuo-spatial perception and memory, and verbal long-term memory. These findings, in line with evidence from brain-damaged patients, normal subjects and children, suggest that phonological short-term memory plays a crucial role in vocabulary acquisition, which may occur in the presence of substantial deficits of general intelligence and episodic memory.
Adult↗
Ideomotor apraxia without aphasia and aphasia without apraxia: the anatomical support for a double dissociation.
This study aimed to verify the existence of a double aphasia/apraxia dissociation. Apraxic patients without aphasia and aphasic patients without apraxia were included in a consecutive series of patients with cortical or subcortical CT documented vascular lesions in the left hemisphere. Of 699 patients, 10 were found to be apraxic but not aphasic and 149 aphasic but not apraxic. These findings indicate an aphasia/apraxia double dissociation. This suggests that praxis and language make use of two different, partly overlapping networks.
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Long-term recency effects and phonological short-term memory. A neuropsychological case study.
Long-term recency effects were investigated in a left brain-damaged patient, PV, who had a pathologically low auditory-verbal span and a lack of the normal recency effects in immediate free recall of auditorily presented lists of words, attributed to the abnormally reduced capacity of the phonological short-term store component of memory (Vallar and Papagno, 1986). In a task requiring the delayed free recall of a list of anagram solutions the patient showed both a recall performance level and a long-term recency effect comparable to the control group. These findings dissociate long and short-term recency phenomena, which would reflect the operation of different memory components. A collateral finding was PV's difficulty in anagram solving, which may be traced back to the defective function of her phonological short-term store.
Adult↗
Parkinson's disease patient's behaviour in a covered maze learning task.
A computerized maze task was constructed that allowed only partial vision of the maze structure and produced measurements for separate analysis of cognitive processes described as impaired in Parkinson's disease. Eighteen patients suffering from mild Parkinson's disease and 18 individually matched normal controls were investigated. Baseline task response times were found to be identical for both groups. Differences between patients' and controls' performance could be related to (a) a response bias in Parkinson patients that favoured repetition of the previous action and slowed down shifting and (b) an impairment of multistep plan generation. It is speculated that the response bias reflects the disinhibition of cortico-thalamo-cortical reverberation loops which results from striatal dopamine depletion.
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Language and verbal memory after right hemispheric stroke: a clinical-CT scan study.
The performances on language and verbal memory tests of 26 right-hemisphere damaged subjects (RHD) have been compared with normal controls and 11 non-aphasic left-hemisphere damaged subjects. While phonological and syntactic performance was unimpaired, a small subgroup of RHD patients, with CT scan evidence of subcortical lesion, was mildly impaired in naming tasks. The performance of RHD patients on free recall was characterized by a reduced recency effect. The implications of these findings for theories about the participation of the right hemisphere in linguistic functions are discussed.
Adult↗
Dissociations of language functions in aphasics with speech automatisms (recurring utterances).
The linguistic performance of 27 aphasics with frequent production of non-lexical speech automatisms (recurrent utterances; e.g. do-do-do...) in spontaneous speech was investigated. Of the 26 patients examined with the Aachen aphasia test (AAT), 24 cases suffered from global aphasia, one from Broca's aphasia, and one was not classifiable but most resembled the fluent types as Wernicke's or conduction aphasia. While most patients were severely impaired in language comprehension, a subgroup showed impairments on a moderate level. In four cases clear dissociations between oral and written output performance were found. Only one patient, and very rarely so, interspersed his written output with his speech automatism. Analysis of written output within the theoretical framework of the logogen model provided evidence for the possibility of a partially intact phonological system in patients with speech automatisms. Results are interpreted as supporting a sub-phonemic hypothesis of the generation of non-lexical speech automatisms.
Adult↗
A case of amnesia after excision of the septum pellucidum.
Tumours of the septum pellucidum (SP) are rare and seldom associated with memory impairment either before or after operation. A patient is described who developed amnesia after transcallosal excision of a tumour of the SP. Radiology did not show any major lesion of the brain areas traditionally associated with amnesia. Because septal nuclei could have been damaged during surgery their possible role in memory functions is discussed.
Adult↗
Patterns of lateralization and performance levels for verbal and spatial tasks in congenital androgen deficiency.
The effects of congenital deficiency of gonadal hormones on verbal and spatial performance and on the establishment of hemispheric asymmetries were investigated in a group of patients with idiopathic hypogonadotropic hypogonadism. The patients showed a left hemispheric advantage for verbal material and were mildly impaired, mainly on tasks involving a short-term memory load, in comparison with a matched control group. These results do not indicate a specific role of gonadal hormones on the establishment of hemispheric asymmetries. Lack of exposure during brain development results in a decrease in memory functions which is not specific for verbal or spatial material.
Adolescent↗
Crossed aphasia: functional studies with single photon emission computerized tomography.
The correlation between clinical picture, CT scan and regional cerebral blood flow (rCBF) assessed by single photon emission computerized tomography (SPECT) was investigated in two patients with crossed aphasia. The presence and degree or right hemisphere dysfunction, beyond the areas affected by CT, closely paralleled the time course of language disturbances in both patients: transient aphasia in case 1 was associated with temporary reduction of perfusion in the right hemisphere, while in case 2 persistent aphasia and apraxia were found along with severe right hemisphere hypoperfusion three year after the onset of stroke.
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Verbal and spatial immediate memory span: normative data from 1355 adults and 1112 children.
Norms are provided for verbal and visuo-spatial immediate memory span, two tasks widely used in the clinical assessment of short-term memory and its neurological disorders. Data have been collected from 1355 male and female adult subjects, with various educational backgrounds and a 20-99 years age range. Span shows a major decrement after the late sixties and is affected by educational level. Male subjects score better on the spatial task. Data collected from 1112 male and female children, 4-to-10 year-old, show that span increases with age and boys score better on the spatial test.
Adult↗
Balint syndrome: a case of simultanagnosia.
We describe a patient with a bilateral posterior lesion, who showed optic ataxia, gaze apraxia and the symptom which most authors call the inability to see more than one thing at a time. We discuss the last feature and the term simultanagnosia sometimes used to indicate it. Furthermore we stress the unusual localization of the lesion in this patient.
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