Biomedical subjects

Valeria Drago

Publications and source records attributed to Valeria Drago.

7 recordsLinked to original sources

PubMed2007

Asymmetrical alien hands in corticobasal degeneration.

There are several forms of alien limb, but alien limb in corticobasal degeneration (CBD) is not well understood. We studied a patient with CBD who demonstrated two different types of alien limb. With his right hand he demonstrated a tactile avoidance response with levitation. With his left hand, he demonstrated continuous tactile pursuit of the examiner's hand ("tactile mitgehen"). Mitgehen is often associated with frontal dysfunction, but avoidance response and levitation are often associated with parietal dysfunction.

Agnosia↗

PubMed2007

Carbidopa/levodopa-responsive myoclonus.

A 64-year-old right-handed woman's right hand and arm developed spontaneous jerks that eventually involved her trunk. As she had some features of parkinsonism, she was treated with carbidopa/levodopa and her myoclonus dramatically improved. The mechanism accounting for this improvement is unknown.

Antiparkinson Agents↗

PubMed2006

Ipsilateral motor activation during unimanual and bimanual motor tasks.

OBJECTIVE: To test for the presence and possible asymmetry of ipsilateral motor activation during unimanual and bimanual motor tasks. METHODS: Twelve right-handed healthy subjects underwent motor evoked potential (MEP) measurement of one hand (target-hand) while the other hand (task-hand) performed different motor tasks. The target-hand was either at rest (first experiment) or performed a Perdue PegBoard task (second experiment). The task-hand was either at rest, performed a simultaneous pegboard task, or rotated a coin (second experiment). RESULTS: In the first experiment, the motor task resulted in significant increase in MEP area in the target-hand, regardless which hand was the task-hand, with a greater increase when the left hand was the task-hand. In the second experiment, ipsilateral motor activation was not present for either hand, however, when the right hand was the task-hand, performance of continuous coin rotation by the right hand resulted in a significant decrease in the MEP area of the left hand. CONCLUSIONS: Hemispheric asymmetry and task-dependence of ipsilateral motor cortex activation supports the postulate that motor activity may start bilaterally with subsequent interhemispheric inhibition. Furthermore, in right-handers, the left motor cortex is either more active in ipsilateral hand movements or exerts more effective inhibitory control over the right motor cortex than vice versa. SIGNIFICANCE: We suggest that hemispheric asymmetry in ipsilateral motor control is a factor in determining motor dominance in right-handed individuals.

Adult↗

PubMed2006

Lewy body dementia and creativity: case report.

BACKGROUND: We studied a visual artist with Lewy body dementia (LBD) to learn how this disease influenced his paintings during the course of the disease. METHODS: Study 1 evaluated two paintings of the same subject matter, one that the patient painted before his illness and the other after the onset of this disease. Study 2 evaluated a collection of his paintings from the time before he was ill (1994) until the time he stopped painting when he was suffering with LBD (2002). To learn how the onset and progression of LBD affected his paintings we had judges score the following qualities: aesthetic-beauty, closure completeness, evocative impact, novelty, technique and representational quality. RESULTS: In Study 1 we found that the representational ratings for the picture he painted when he had LBD was significantly lower than the picture he painted before he developed LBD. In Study 2, we found that all the artistic qualities measures temporally declined except novelty. We also found that the paintings that were judges as having the highest quality representations were significantly more novel than those that had poorer representations. In addition, we conducted a forward stepwise regression analysis using quality measures as predictor of year. This analysis revealed that only representational quality significantly predicted painting year. CONCLUSIONS: Our results suggest that as LBD progresses, except for novelty there is a gradual degradation of the ability to visually express artistic subject matter. It possible that the preserved ability to paint novel picture is related to relative preservation of frontal lobe function, but the degradation of other artistic qualities might be related to deterioration of the parietal lobes which either impairs the brain's iconic representations or the knowledge needed to portray these representations.

Adult↗

PubMed2006

Ipsilesional attentional-approach neglect or crossover effect.

Patients with ipsilateral neglect (IN) bisect lines toward contralesional space. It has been posited that IN might be induced by an attempt at compensation, as part of the crossover effect, where patients with an ipsilesional bias when bisecting long lines, cross over and develop a contralesional bias on short lines or as a release of an approach (grasp) behavior that might be attentional or intentional. To test these alternative hypotheses we had a patient with IN from a right medial frontal lesion bisect lines that contained no cue, a left-sided cue, a right-sided cue, and bilateral cues. If this patient had ipsilateral neglect (IN) because of a crossover effect or compensation, right-sided cues should have influenced bisection more than left-sided cues. We, however, found that only left-sided cues induced a significant change (left-sided deviation) providing support for the attentional-approach (grasp) hypothesis. Further support of this contralesional attentional grasp hypothesis comes from the observation that this patient also had ipsilesional extinction to simultaneous stimuli.

Attention↗

PubMed2006

Radial character-line bisection.

BACKGROUND AND OBJECTIVES: With conventional solid radially oriented-line bisections (SLB), normal subjects tend to bisect distal to the true midpoint (distal bias). This bias is thought to reflect a distal attentional bias in the radial plane. Whereas the right hemisphere, which mediates distributed-global attention, has a distal bias, the left hemisphere, which mediates focal attention, has a proximal bias. When performing conventional radial-line bisections, participants might primarily use right hemisphere-mediated global-distributed attention and thus develop a distal bias. The character-line bisection (CLB) task consists of strings of target and nontarget characters (letters or symbols) that are linearly aligned, and subjects are required to bisect a character that is closest to the midline. Thus, when performing the CLB subjects must use focal attention and detect symbols and both these activities are mediated by their left hemisphere. This left hemisphere activation might either reduce or reverse the distal bias observed on the SLB. The purpose of this study is to test this hypothesis. METHODS: Fifteen normal subjects performed CLB (letter-line and symbol-line) and SLB tasks. RESULTS: Overall, the subjects revealed a distal bias in both tasks, but the attempted bisections in the CLB tasks were more proximal than those in the SLB tasks. CONCLUSIONS: These result are consistent with the hypothesis that the CLB task, which requires both focal attention and the detection of symbols, activates the left hemisphere that has a greater proximal bias than the right hemisphere, thus reducing the distal bias observed with the SLB task.

Adult↗

PubMed2006

Distribution of attention in normal people as a function of spatial location: right-left, up-down.

The spatial allocation of attention influences estimates of stimulus magnitude, including line length and the line bisection task has been used to assess the asymmetrical allocation of spatial attention. The purpose of this study is to learn if normal subjects' allocation of attention changes as a function of the trunk-head centered spatial position of the line stimuli. Normal subjects were asked to bisect lines placed in five different head-trunk centered special positions (central, right up-distal, left up-distal, right down-proximal, left down-proximal). When compared with the central condition, deviations in the right or left lateral conditions were only significant in the down-proximal conditions, such that the bisection bias significantly shifted direction to the left of the objective midline in left hemispace and to the right of the objective midline in right hemispace, suggesting that stimuli presented in lateral hemispace primarily activate the contralateral hemisphere's attentional systems. The finding that the lines presented in down-proximal lateral hemispace induce a greater spatial bias than lines in up-distal lateral space suggests that the portion of the brain's dorsal visual system, which processes stimuli in down-proximal space, influences the horizontal (right-left) spatial allocation of attention more than does the brain's ventral visual system.

Adult↗