Biomedical subjects

L Pizzamiglio

Publications and source records attributed to L Pizzamiglio.

At least 55 records · Page 3Linked to original sources

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↗

PubMed1992

Pattern of CBF in the rehabilitation of visuospatial neglect.

The CBF was assessed in seven patients before and after rehabilitation for visuospatial neglect. Two months of treatment produced an increased perfusion both in the right posterior and left anterior areas of the brain. However, only the left anterior CBF increase was correlated with the neglect disorders. The left anterior improvement in CBF was inversely correlated with right-left cerebellum asymmetry in pre- and post-treatment. The present data suggest the role of the frontal eye-fields in the mechanism of recovery of visual exploration in patients with severe neglect.

Adult↗

PubMed1991

Disappearance of leftward rapid eye movements during sleep in left visual hemi-inattention.

Contrasting hypotheses have been proposed about the functional equivalence between waking saccades and REMs. Patients with left visual hemi-inattention showed dissociation between the direction of waking saccades and that of REMs. REMs directed toward the left were virtually absent, while waking inspective saccades directed in both lateral directions were present, but confined to the right hemispace. It is concluded that: a) the cortical areas regulating attention are relevant in the production of REMs; b) two separate attentional mechanisms have to be considered in relation to the hemi-inattentive syndrome, one is involved in the cognitive control of visual exploration and plays little or no role in the modulation of REMs, the other deals with REMs during sleep and with reflex-like orienting responses to peripheral stimuli during waking.

Aged↗

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

Effect of optokinetic stimulation in patients with visual neglect.

Three groups of subjects, normal controls, right brain damaged patients with and without heminattention, were required to bisect a line in presence of a fixed or a moving background. The stimulus moving horizontally toward the left or the right induced an optokinetic nystagmus with a slow phase coherent with the direction of the movement: together with the optokinetic nystagmus, a displacement of the subjective midpoint, as compared to the condition with a fixed background, was observed in all three groups of subjects. Within the right brain damaged with heminattention the displacement of the line bisection was great for stimuli moving toward the right, but a significant reduction of the left bias was present. In the same group of patients the effect of the optokinetic stimulation was present in a very large proportion of cases and proved to be relatively stable in a test-retest presentation. Theoretical relevance of these data and their potential importance for rehabilitation are discussed.

Attention↗

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↗

PubMed1987

Imitation of facial movements in brain damaged patients.

The imitation of a large repertoire of upper and lower facial actions was requested from a group of left, right brain damaged and control subjects in order to explore: (1) if a left or right hemispheric focal lesion produces a similar pattern of impairment on this task; (2) if the impairment is associated with oral apraxia. The results show that left and right brain damaged patients score significantly lower than controls but the two pathologic groups do not differ from each other. The imitation of facial movements is not related in any way to oral apraxia and no specific localization of the lesion seems responsible for the impairment in this task. It is suggested that the control of facial movements might have a multiple representation in either hemisphere.

Apraxias↗

PubMed1986

Simultaneous binocular integration of the visual tilt effect in normal and stereoblind observers.

Apparent displacement of an edge from the subjective visual vertical is typically induced by the simultaneous inspection of a large rotating textured background. In the present series of experiments we have tested the binocular integration of such an effect in normal and stereoblind observers in whom inspection of the rotating background and vision of the vertical edge are presented to different eyes. In normal subjects there was no difference between the binocular and the dichoptic viewing condition while in stereoblind subjects there was a clearcut decrease in the strength of the tilt effect under dichoptic conditions. A residual tilt effect, however, was still present in the latter group under dichoptic conditions and this shows that binocular interactions related to visual tilt can be dissociated from those required for stereopsis.

Adolescent↗

PubMed1985

Evidence for sex differences in brain organization in recovery in aphasia.

Ninety-one adult aphasics of both sexes were studied before and after a 3-month period of language therapy. Although no initial sex difference was found in severity of language disorders, females within the global aphasic group showed significantly greater improvement in three tests of language comprehension. It is suggested that more bilateral representation of language functions in the female brain may account for this greater improvement.

Aged↗

PubMed1984

Response of the cortically blind hemifields to a moving visual scene.

Viewing a rotating field induces a counter-rotating tilt of the subjective vertical in normal subjects. A similar, though smaller, effect is observed when only one hemifield is stimulated. This technique was used with 7 hemianopic patients having retrogenicular lesions. It was hypothesized that the stimulation of a moving scene in the blind field produces an additional tilting effect to that produced by the stimulation of the normal hemifield alone. The visual rotation within only the blind field is expected to have a systematic tilting effect. Both predictions were confirmed in all 7 patients having either right or left hemianopic disorders.

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

Hemiretinal differences in the effect of a rotating visual background on the subjective visual vertical.

Sixteen normal subjects were tested for their accuracy in judging the verticality of a visual edge before or during exposure to a moving visual background. All subjects showed a counter-rotation of the subjective visual vertical as a consequence of movement of the visual background. The effect was stronger for binocular than monocular viewing and for nasal than temporal hemiretina stimulation. No hemispheric asymmetries were observed. These results show a predominance of the crossed visual pathways originating from the nasal hemiretinae in a visual effect presumably involving a visual-vestibular interaction.

Adolescent↗