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Biomedical subjects

P Zoccolotti

Publications and source records attributed to P Zoccolotti.

At least 37 records · Page 2Linked to original sources
PubMed1992

Perception of moving and stationary gratings in brain damaged patients with unilateral spatial neglect.

Contrast sensitivity for stationary and drifting sinusoidal gratings of different spatial frequencies was measured in 17 brain damaged patients (five left-brain damaged and 12 right-brain damaged patients, six of whom showed symptoms of spatial hemi-neglect). Twenty-nine combinations of spatio-temporal stimuli were considered in the drifting condition. No specific deficit for the group of patients with neglect symptom in the perception of moving and stationary gratings was observed. Also, no systematic deficit for perceiving the direction of motion--toward the neglect hemispace or away from it--was apparent. A small, selective impairment in the detection of stationary or very slow drifting gratings of low spatial frequency was observed in the presence of unilateral cortical damage, independently from its side (left or right) and from the presence of neglect. Some difficulty to detect the direction of motion was observed in a few individual patients.

Aged↗
PubMed1992

Cognitive rehabilitation of the hemineglect disorder in chronic patients with unilateral right brain damage.

Thirteen patients with a stabilized hemineglect symptomatology due to right-hemisphere lesions were subjected to a rehabilitation training specifically aimed at reducing the scanning deficit. The training consisted of four procedures (visual-spatial scanning, reading and copying training, copying of line drawings on a dot matrix, and figure description) which lasted 40 sessions. By the end of therapy, the patients as a group showed significant improvements on several standard tests of hemineglect. The results on a Semi-structured Scale for the Functional Evaluation of Hemineglect pointed to the extension of exploratory improvements to situations similar to those of daily life. In contrast, patients improved very slightly on a variety of standard visual-spatial tests, indicating the specificity of training in reducing the scanning defect. Seven patients were examined at a follow-up several months after the end of therapy and appeared stable on both standard and functional tests of neglect.

Aged↗
PubMed1992

Good recovery in visual scanning in a patient with persistent anosognosia.

A patient with hemineglect disturbance (N.G.) due to a right hemispheric lesion was admitted to rehabilitative training which featured the use of procedures devised in a previous study (Pizzamiglio et al., 1990) both in a standard way and with the addition of optokinetic stimulation. This latter paradigm produces an automatic reaction which favors the spatial orienting of the patient toward his (left) neglected side. N.G. showed good recovery in visual scanning and, by the end of training, reached a level of recovery similar to other neglect patients. However, his recovery was particularly slow and no change was observed in his attitude toward the visual disturbance. The conclusion is reached that recovery in visual scanning also can be obtained in patients with persistent anosognosic disturbances. Stimulations such as the optokinetic condition which influence patients' behavior at an automatic level may play an important role in this recovery. CBF studies obtained before and after training showed a CBF improvement mainly in the right temporoparietal regions, behind the lesion, and in the left frontal cortex. The implications of these findings on various theoretical interpretations of the hemineglect disturbance are briefly discussed.

Adaptation, Psychological↗
PubMed1991

Semantic processing of unattended parafoveal words.

The influence that a context word presented either foveally or parafoveally, may exert on the processing of a subsequent target word was studied in a semantic decision task. Fourteen subjects participated in the experiment. They were presented with word-nonword pairs (prime). One member of the pair (which the subjects had to attend to) appeared centrally, the other parafoveally. The prime was followed by a target at two inter-stimulus intervals (ISI; 200 and 2000 msec). The word stimulus of the pair could be semantically related or unrelated to the target. The subjects' task was to classify the target as animal or not animal by pressing one of two buttons as quickly as possible. When the target word was semantically associated with the foveal (attended) word the reaction times were faster for both ISIs; when it was associated with the parafoveal (unattended) word in the prime pair, there were facilitatory effects only in the short ISI condition. A second experiment was run in order to evaluate the possibility that the obtained results were due to identification of the parafoveal stimulus. The same prime-target pairs of experiment 1 (without the target stimuli) were used. The prime-target pairs were presented to fourteen subjects who were requested to name the foveal (attended) stimulus and subsequently, if possible, the parafoveal (unattended) one. Even in this condition, percentage of identification of the unattended word was only 15%, suggesting that previous findings were not due to identification of unattended stimuli. Results are discussed in relation to Posner and Snyder's (1975) dual coding theory.

Adult↗
PubMed1990

Contrast sensitivity and low spatial frequency discrimination in hemi-neglect patients.

Contrast sensitivity for sinusoidal gratings of different spatial frequencies and low spatial frequency discrimination of high contrast squarewave gratings were measured in 26 right brain damaged patients, 15 of whom showed symptoms of spatial hemi-neglect. No difference was present between neglect and non-neglect patients in either task. A difference in contrast sensitivity restricted to low spatial frequencies was present between controls and patients, independent of neglect. Overall, results indicated that spatial vision at threshold and suprathreshold levels is not selectively impaired in patients with hemi-neglect, a finding consistent with theories which postulate a post-perceptual locus of impairment in this syndrome.

Aged↗
PubMed1990

Shape, size and relative space position perception in neglect patients.

Shape, size and relative position in space perception were tested in 17 right brain damaged (RBD) patients with neglect symptoms, 10 RBD patients without neglect and 11 controls. Simultaneous pair comparison task in free vision was used. Two arrangements of the visual display were used: side by side and top-bottom. Neglect patients' performance was comparable to RBD and controls in the shape and size test, but was below the other groups in the relative space position test. The selective failure of neglect patients in the position task did not depend on the spatial arrangement of the visual display, which may indicate a general perceptual deficit, rather than a deficit restricted to the neglect hemifield.

Aged↗
PubMed1989

Posed emotional expression in unilateral brain damaged patients.

The facial expressions of six basic emotions were posed by two groups of right (N = 23) and left (N = 34) brain damaged patients and by a control group of normal subjects (N = 28). The posed expressions were examined by means of the Facial Action Coding System (FACS) which provides analytical and objective scoring, as by a subjective scale of appropriateness of expression. Results indicated no difference between controls and patients with a lesion in the right or left hemisphere. These findings are inconsistent with the hypothesis that the right hemisphere plays a specific role in the control of posed facial expression. No relationship was observed between posed emotional expressions and facial paralysis or the presence of oral apraxia.

Affect↗
PubMed1989

Visual neglect for far and near extra-personal space in humans.

The possible dissociation of unilateral neglect in far and near extra-personal space was systematically investigated using a modified version of the Wundt-Jastrow area illusion test. This task, which requires no motor response, has been shown to be sensitive to unilateral neglect. Stimuli were presented at two different distances (near and far) to a group of 70 patients with right hemispheric lesion (18 in acute and 52 in chronic stage). Twenty-eight patients evidenced unilateral neglect; that is, they displayed unexpected (i.e., contrary to the known illusory effect) responses when the stimuli were perceived as oriented toward the left side. However, performances in the two conditions were highly correlated and there were no individual instances of dissociation. These results suggest that the presence of a motor response may be necessary to show behavioral dissociations between different parts of extra-personal space.

Adult↗
PubMed1989

Incidence and evolution of the hemineglect disorder in chronic patients with unilateral right brain damage.

One hundred four patients with a unilateral right hemispheric lesion, consecutively admitted to a rehabilitation clinic, were examined to evaluate: 1. the incidence of patients with severe hemineglect at least two months after the CVA; 2. the role of the length of time from the onset of disease in predicting the severity of the disorder. Estimates of the disorder varied according to the test used, ranging from 26.7% to 52.0%. On the basis of an overall clinical judgment, approximately 20% of patients had very severe hemineglect. Consistent with earlier findings, the severity of the disorder was unrelated to the duration of the disease when examined by means of correlational analyses. However, a subdivision of patients into subgroups according to the length of time from the onset of the disease showed a trend for a moderate reduction of the severity of the deficit starting from the 3-month subgroup for two tests (Barrage Test and Wundt-Jastrow Area Illusion Test).

Adult↗
PubMed1988

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↗
PubMed1988

The Wundt-Jastrow illusion in the study of spatial hemi-inattention.

A new test to detect unilateral neglect was devised using a modified version of the Wundt-Jastrow area illusion. The test was given to three groups of subjects: left brain damaged (LBD), right brain damaged (RBD) patients and controls. Of RBD patients, 40.4% but no LBD patient or control, showed responses inconsistent with the visual illusion when the determinant features of the illusion pointed to the left visual field. These unexpected responses were highly related to a clinical evaluation of the severity of the hemi-inattention disorder. The sensitivity of this test and of other standard measures of hemi-neglect were compared. The possibility of identifying qualitatively different forms of hemi-neglect was also discussed.

Aged↗
PubMed1988

Spontaneous facial expression of emotions in brain-damaged patients.

Spontaneous facial expression of emotion was studied in two groups of right (N = 23) and left (N = 39) brain-damaged patients and in a control group of normal subjects (N = 28). To elicit emotions four short movies, constructed to produce positive, negative or neutral emotional responses, were used. The method used to assess the facial expression of emotions was the Facial Action Coding System. Brain-damaged patients showed less facial responses to emotional stimuli than normal controls, but no difference was observed between subjects with right and left-sided lesions either with global or disaggregated data analyses, inconsistent with the hypothesis of a specialization of the right hemisphere for facial emotional expressions. An unexpected difference was observed in response to the unpleasant movie. Both normal controls and left brain-damaged patients often averted their gaze from the screen when unpleasant material was displayed, whereas right brain-damaged patients rarely showed gaze aversion. This finding suggests that the degree of emotional involvement or manner of coping with stressful input may be reduced as a result of right brain damage.

Affect↗
PubMed1988

The effect of rehearsal on hemispheric processing in a memory recognition task.

The effect of rehearsal on right and left hemisphere performance was investigated in a recognition task in which a lateralized picture probe followed the presentation of two words in central vision. Half the 16 right-handed subjects rehearsed the pair of words vocally and half subvocally. Four different interstimulus intervals (0.5 s, 1.5 s, 3 s and 5 s) between words and picture probes were considered. Results showed no difference between the vocal and subvocal rehearsal conditions, an overall LVF right hemisphere advantage, and a trend in the linear component of the interaction visual field X interstimulus interval, indicating that the LVF advantage decreases as the interstimulus interval increases.

Adult↗
PubMed1983

The independence of face identity and facial expression recognition mechanisms: relationship to sex and cognitive style.

Two tasks, one mapping the recognition of unfamiliar face identity and the other the identification of six facial expressions were unilaterally presented to field dependent and field independent individuals of both genders. Regardless of sex, field independent subjects showed faster-response times (RTs) in the left visual field (LVF) for face identity and for the identification of disgust and fear and faster RTs in the RVF for the identification of anger. A trend toward LVF superiority was found over the whole sample for the facial expression task; this effect was still present when the face identity task was partialled out, indicating the independence of the underlying mechanisms.

Adolescent↗
PubMed1982

Electrodermal responses in patients with unilateral brain damage.

Skin conductance responses (SCR) to emotional and to nonemotional stimuli were measured in 16 right and 16 left unilateral brain-damaged patients. Replicating findings by Morrow, Vrtunski, Kim and Boller (1981), those patients with a lesion in the left hemisphere showed higher SCR's to emotional than to nonemotional stimuli while those with a right lesion showed no difference between them. This pattern of results remained when variance in performance on a Facial Expression Recognition task was partialled out, suggesting that the absence of differentiated arousal in right-brain-damaged patients is unrelated to their impairment in perceptual analysis.

Arousal↗