| Name | Dario |
| Surname | Grossi |
| Institution | Università degli Studi della Campania Luigi Vanvitelli |
| dario.grossi@unicampania.it | |
| Address | Villa Camaldoli Foundation Clinic, Naples, Italy; Department of Psychology, University of Campania "Luigi Vanvitelli", Napoli, Italy |
We report the case of a patient affected by a subcortical lesion of the right non-dominant hemisphere, and demonstrate that he had selective constructional disorders by comparing his post-stroke performances with those assessed 18 months before the stroke. A detailed analysis was made of the visuospatial, perceptual, representational and executive competences involved in drawing tasks at one, two and six months post-stroke. Neuropsychological follow-up revealed the progressive recovery of all visuospatial abilities. This study provides some interpretative elements for constructional disorders and, in particular, for the closing-in phenomenon observed only during the subacute phase.
A patient with selective auditory phonological coding defect is described. He also showed a defective auditory verbal short-term memory but could learn lists of words flawlessly, thus closely resembling patients with pure short-term memory defects. We argue that the patient's functional defect could be conceived as a capacity limitation of the phonological short-term store. An experimental evaluation of his verbal short- and long-term memory performances allows a discussion of the interaction of phonological and lexical coding processes in verbal short-term memory and learning.
The present study aimed at controlling two variables that may affect the visuospatial short-term memory of Alzheimer patients: visuospatial coding efficiency and response modality. Thirty patients affected by Alzheimer-type dementia with relatively spared visuo-perceptual functions were tested under three conditions, all of which employed the same kind of stimuli (visuospatial patterns). At all memory tasks, patients achieved scores significantly lower than those of 30 age- and education-matched normal subjects. Patients did not benefit from longer presentation time, nor did their performance improve with pointing response modality, although they performed perceptual pattern recognition as well as did controls. These data confirm that visuospatial immediate memory capacity is reduced in dementia.
The purpose of the present study was to investigate the imagery ability of 8 "probable" Alzheimer disease patients using a standard task sensitive to the disruption of the imagery system. These patients were selected based on their good performance on a prerequisite clock-setting task, and with 8 matched control subjects were then required to compare the angles made by the hands on clock faces using only imagined stimuli. There were no significant differences between patients and controls in performance on the clock-imagery task. These data are consistent with models of information processing which postulate the relationships between visual imagery and a short-term memory store and include a central executive system for allocation of cognitive resources.
Corsi's block-tapping task was given to 30 normal subjects and 38 Alzheimer-type demented patients following two different procedures. The first is the most widely standardized (scoring criterion: 3 correct reproductions out of 5 sequences), while the second is more lenient since it does not require subjects to replicate a certain performance three times. Demented patients' scores were lower than those of controls in both conditions, and scores on the two tasks were significantly correlated for patients and controls. However, the requirement of replicating the visuospatial memory performances was more detrimental for demented patients than for controls so the two procedures cannot be considered equivalent.
A critical, clinical review of single-case reports and group studies on visual mental imagery deficits is offered. Neuropsychological findings demonstrate that mental imagery relies upon dissociable processes which are localized in left-hemisphere posterior areas. Imagery defects thus may often be associated with visual recognition and naming impairments. On the other hand, the right hemisphere seems to play an analogous role in imagery and perception. Current theoretical models of imagery do not appear fully capable of accounting for available clinical data.
We report an Italian patient affected by slowly progressive aphasia (SPA) lasting since four years when he first came to our observation. During the successive four years, we documented a progressive language decline resembling transcortical sensory aphasia, associated with a reading disorder corresponding to surface dyslexia, a form extremely rare in patients with native transparent language. His performance at standard intelligence tasks remained in the normal range, without any variation. CT scan showed left temporal atrophy. We emphasize the heterogeneity of the syndrome of SPA and suggest that it can represent one of the pictures of focal cortical degenerative disease, with variable onset, progression, and evolution.
Immediate memory for visuospatial information was assessed in patients affected by Alzheimer-type dementia but with unimpaired visuo-perceptual functions. Patients were given two tasks: one was a traditional visuospatial memory task (Corsi's block tapping test), the second explored specifically immediate memory for visuospatial patterns. The experiment was conducted in two parallel groups of patients in Italy and the United States, each with its own appropriate sample of normal control subjects. Results showed a specific deficit of visual working memory in demented patients, even in a task in which control subjects achieved error-free performance. These data are interpreted in the light of the Working Memory Model, and suggest that in dementia the functions of the Visuospatial Scratchpad, unlike the functions of the verbal subsystems, may be impaired.
We aimed to ascertain whether non-apraxic, focal brain-damaged patients used abnormal constructional procedures. We tested a series of consecutive patients, classified according to lesion locus and side against a matched sample of normal volunteers. Subjects had to copy the Rey-Osterreith Figure, a complex and structured item that explores copying strategies. We used special testing and scoring methods to analyze different steps of the copy. Unlike the controls, the patients did not choose the central elements of the figure as guiding structures. All patient groups followed an equivalent "pathological", "piecemeal" procedure.
A case is reported of an associative visual agnosic patient who could not draw from memory objects he could recognize, even though he could copy drawings flawlessly. His ability to generate mental visual images was found to be spared, as was his ability to operate upon mental images. These data suggest that the patient could generate mental images but could not draw from memory because he did not have access to stored knowledge about pictorial attributes of objects. A similar functional impairment can be found in some other visual agnosic patients and in patients affected by optic aphasia. The present case allows a discussion of relationships among drawing from memory, imagery, and copying procedures.