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Biomedical subjects

G Geminiani

Publications and source records attributed to G Geminiani.

16 recordsLinked to original sources
PubMed1998

Dopaminergic stimulation in unilateral neglect.

OBJECTIVE: To explore the hypothesis that dopaminergic circuits play a part in the premotor components of the unilateral neglect syndrome, the effects of acute dopaminergic stimulation in patients with neglect were studied. METHODS: Two tasks were evaluated before and after subcutaneous administration of apomorphine and placebo: a circle crossing test and a test of target exploration (a modified version of the bell test), performed both in perceptual (counting) and in perceptual-motor (pointing) conditions. SUBJECTS: Four patients with left neglect. RESULTS: After dopaminergic stimulation, a significant improvement was found compared with placebo administration and baseline evaluation, in the performance of the two tests. Three of the patients had a more marked improvement in the perceptual-motor condition (pointing) of the task than the perceptual condition (counting). CONCLUSIONS: The findings suggest that dopaminergic neuronal networks may mediate, in different ways, both perceptive and premotor components of the unilateral neglect syndrome.

Acute Disease↗
PubMed1996

Cabergoline in Parkinson's disease complicated by motor fluctuations.

Cabergoline is a long-acting D2 dopamine (DA) agonist. We conducted an open study to investigate the effectiveness and tolerability of cabergoline, administered once a day orally, in 50 consecutive patients with Parkinson's disease complicated by motor fluctuations and dyskinesias. In 15 patients cabergoline replaced another direct DA agonist. Evaluation after 6 months of treatment (also including patients who dropped out during this period), showed an improvement in off or on hours, or both, in excess of 50% in 27 patients, comprising 20 of the 35 patients (57%) previously untreated with DA agonists and seven of the 15 patients (47%) already on DA agonists when the study began. Of the 22 patients who received the treatment for 1 year, the improvement was maintained up to final evaluation in the patients not on DA agonists at admission (n = 16), whereas a slight deterioration in clinical condition was observed in the patients already on DA agonists at admission (n = 6). Only six patients showed a detectable increase in dyskinesias. The most common side effects were gastric upset (n = 12), orthostatic hypotension (n = 3), and ankle edema (n = 3), all mild; also observed were two cases of pleural effusion/pulmonary fibrosis. Twenty patients (40%) failed to complete the treatment; of these, five (10% of total) dropped out because of adverse effects. It is concluded that once-daily administrations of cabergoline are useful for treating patients with Parkinson's disease with motor fluctuations and may advantageously substitute other DA agonists. The side effects of the drug are generally mild, although two cases involving pleuropulmonary complications did emerge.

Aged↗
PubMed1995

Analogical representation and language structure.

Severe impairment of the analogue of mental representation is not compensated for by putative language-based cognitive processes in non-dysphasic brain-damaged patients. This undermines the hypothesis of an independent role for language in the generation of thought. Against this view it may be contended that there seems to be no obvious way in which analogical mental representation can decide between alternative syntactical structures available for the expression of thought. We performed a visual imagery experiment in which we asked 40 subjects to imagine visual scenes representing the meanings of simple utterances presented to them. The subjects then had to indicate the relative position, in each visual image, of two objects mentioned in each utterance. Series of utterances were presented differing syntactically (active or passive phrase) and semantically (specifying in different ways the spatial and temporal relations between the objects mentioned). The results of this mental imagery experiment indirectly support the hypothesis that syntactical structures can be represented in a nonlinguistic analogue medium.

Adult↗
PubMed1994

Anatomical correlates of visual and tactile extinction in humans: a clinical CT scan study.

The anatomical correlates of tactile and visual extinction with double simultaneous stimulation were investigated in a series of 159 patients with right brain damage caused by stroke. Forty six patients showed extinction (22 tactile, 14 visual, 10 tactile and visual). Over 50% of the patients with extinction had deep lesions, which were found in about 25% of the patients with visuospatial neglect not associated with extinction. In the patients with extinction and cortico-subcortical damage the paraventricular occipital white matter and the dorsolateral frontal cortex were most often involved. By contrast, when neglect was also present, the lesions clustered in the inferior parietal lobule. These data suggest, from an anatomical perspective, that partly different neural mechanisms may underlie neglect and extinction. The comparatively high frequency of subcortical lesions involving the ascending pathways may be a neural correlate of a sensory component of extinction.

Adolescent↗
PubMed1991

Early-onset Parkinson's disease.

The study was conducted on 120 patients (76 men and 44 women) affected by idiopathic Parkinson's disease (IPD) responsive to L-dopa and observed for many years. Sixty had clinical onset between the ages of 20-40, representing 10.2% of our PD population; in the others the symptoms began after the 40th birthday. The two groups were matched for sex and length of illness. In all patients a diagnosis of IPD depended on history and clinical and neuroradiological findings. Clinical, pharmacological, evolutive, and epidemiological data were collected on all patients. Thirty-six patients from each group performed motor dexterity tests (reaction time to expected and unexpected stimuli) and cognitive tests (Wechsler Adult Intelligence Scale. Benton, Short tale, and Zazzo's speed and accuracy test). To assess the prevalence of dementia and the severity of psychiatric side effects of L-dopa administration, the 60 patients with early-onset PD were compared with 134 consecutive unselected PD patients. Five percent of early-onset PD patients had a family history of the disorder. Our study showed that early-onset PD does not differ fundamentally from the late-onset form except that the former is characterized by a more rapid establishment of the full-blown parkinsonian clinical picture and deterioration of the therapeutic efficacy of L-dopa, with an earlier appearance of side effects. The results of our neuropsychological investigations suggest that early-onset PD may be a "pure" form of extrapyramidal compromise with exclusively motor manifestations.

Adult↗
PubMed1991

Interobserver reliability between neurologists in training of Parkinson's disease rating scales. A multicenter study.

A multicenter study has been conducted to determine the interobserver reproducibility of four of the most frequently used rating scales for Parkinson's disease: the Columbia University Rating Scale (CURS) and the Webster Rating Scale (WRS), both for assessing clinical signs; the Northwestern University Disability Scale (NUDS); and the Hoehn and Yahr staging. Four resident neurologists, inexperienced in the use of the four scales, independently examined 48 parkinsonian patients. The extent to which their assessments agreed was determined by calculating the Cohen k index after the scores had been recodified. The physicians' scores agreed substantially for the CURS and the Hoehn and Yahr scale, while those for the NUDS and the WRS agreed only moderately. Analysis of individual item scores within the scales suggests improvements that would offer greater interobserver consistency.

Disability Evaluation↗
PubMed1991

Visual and nonvisual neglect after unilateral brain lesions: modulation by visual input.

A spatial exploratory task was given to 110 patients with unilateral brain lesions [66 right brain-damaged (RBD) patients and 44 left brain-damaged (LBD) patients] in two conditions, with and without the aid of vision. Exploratory deficits mainly involved the contralesional half-space and were most frequently associated with right brain damage. A double dissociation was found between the visual and the nonvisual conditions of the task; selective impairments in the visual and in the nonvisual condition were associated with the presence and the absence of visual field deficits, respectively. The suggestion is made that discrete "visual" and "tactile-kinesthetic" spatial representational systems are involved in exploration of extrapersonal space. A further distinction is made between input and output spatial system. The association between visual field deficits and visual neglect is explained in terms of the impairment of an input visuospatial component, which feeds an output component involved in spatial exploration. Finally, the ambiguous nature of the visual field deficits in neglect patients is discussed and the suggestion is made that an attentional modality-specific nonsensory component may be present.

Brain Damage, Chronic↗
PubMed1990

Topographic disorientation--a case report.

Topographical disorientation can be dissociated in two levels, agnosic and amnesic. A case of topographical disorientation due to a glioma of the splenium of corpus callosum illustrates the dissociation between the topographical memory impairment and the normal performances on the perceptual topographic tests.

Aged↗
PubMed1990

Variation of therapeutic response in Parkinson's disease: a retrospective study.

A retrospective study of variations of therapeutic response (dyskinesia and on-off phenomenon) in Parkinson's disease was conducted on 278 patients treated with levodopa for at least 6 months and hospitalized at National Neurological Institute "C. Besta" of Milan between 1974 and 1984. Variations of therapeutic response (TRV) were present in 105 of 278 patients; in this group, age at illness onset was significantly lower, while duration of levodopa treatment and also duration of illness were longer than in the group of patients without TRV. Multiple logistic regression analysis showed that the most important variables were age at illness onset and duration of treatment, but they were only modestly predictive. Other factors connected with progression of disease must also contribute to the TRV.

Age Factors↗
PubMed1990

Perceptual and premotor factors of unilateral neglect.

Right-brain-damaged patients showing unilateral neglect underwent a specifically devised line-bisection task that allowed uncoupling of the direction of visual attention from that of hand movement. This made it possible to isolate and separately assess perceptual and premotor factors of the disorder. Comparison of experimental and radiologic data suggested that premotor factors were more pronounced in patients with lesions involving the frontal lobes than in patients with lesions confined to postrolandic areas. The technique employed is compatible with bedside examination and provides data useful for standard assessment of neglect symptomatology for both clinical and experimental purposes.

Adult↗
PubMed1989

Influence of response modality on perceptual awareness of contralesional visual stimuli.

Visual extinction on double simultaneous stimulation was investigated in left and right brain-damaged patients in two response conditions: verbal and motor. In right brain-damaged patients contralesional detection was significantly worse when monitored by motor rather than by verbal responses in condition of single as well as of double stimulation. Previous research in normal subjects had shown that the left hemisphere is selectively involved in choice reactions such as those occurring in the motor condition of the present experiment in brain-damaged patients. The results of the latter are interpreted using as a basis the findings of that research and Kinsbourne's hemisphere activation hypothesis concerning unilateral neglect of space.

Analysis of Variance↗
PubMed1989

[Current approaches in the treatment of Parkinson disease].

The latest improvements in Parkinson's disease therapy are reviewed with particular emphasis on the management of long-term treatment syndrome, which has become the chief problem for Parkinson patients since the introduction of levodopa. Current research is directed at overcoming this effect by 1) combining levodopa with new dopamine agonists such as cabergoline or terguride, which have useful pharmacological properties; 2) administering the drugs in different ways to improve their bioavailability (intravenous or subcutaneous infusion); 3) understanding the neurobiological implications of cellular brain grafting; 4) safely transferring the surgical procedure from the experimental to the clinical field.

Delayed-Action Preparations↗
PubMed1988

Relationship between motor and cognitive disorders in Huntington's disease.

Akinesia and mental decline appear to be more appropriate criteria than hyperkinesia for the evaluation of the stage and progression of Huntington's disease (HD). In order to establish the relationship between motor and cognitive impairment in the disease, 20 non-demented HD patients were compared with 44 control subjects with respect to motor and cognitive performance. HD patients were significantly impaired in almost all cognitive functions in comparison with controls. Reaction time (RT) and movement time (MT) were considerably slower in HD patients when compared with controls and with patients with parkinsonism. Hyperkinesias did not correlate with cognitive impairment, but there was a good correlation between RT, MT and cognitive functions. Therefore, it seems that akinesia evaluated by RT and MT is an important sign in HD and proceeds at the same rate as mental decay.

Adult↗
PubMed1988

Role of motor performance in cognitive processes of parkinsonian patients.

Sixty-seven parkinsonian patients and 44 control subjects were tested for cognitive function and motor performance, using reaction times and movement times. Parkinsonian subjects did significantly worse in tests that required visuoperceptual and perceptual motor abilities, such as Object Assembly, Block Design, and Zazzo's test. Analysis of covariance of test scores showed that Block Design and Object Assembly scores were not significantly different between patients and controls when adjusted for reaction and movement times. Also, reaction and movement times were more delayed in parkinsonian patients than in controls. These results stress the main role of motor dysfunction in visuospatial and perceptual motor impairment.

Cognition↗