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Biomedical subjects

D Bowers

Publications and source records attributed to D Bowers.

At least 73 records · Page 4Linked to original sources
PubMed1987

Reduction in cerebral activation after right hemisphere stroke.

Destruction or disconnection of specific neuronal structures or failure to activate those structures may impair brain function. Because the right hemisphere seems dominant for mediating arousal, which is an important determinant of the capacity for cerebral activation, we predicted that subjects with right hemisphere damage would have a greater reduction in the capacity for cerebral activation than subjects with left hemisphere damage. A paradigm requiring that two simple tasks be performed singly and simultaneously was used to assess the capacity for activation. Subjects with right hemisphere damage had significantly greater impairment in the capacity for cerebral activation than subjects with left hemisphere damage. This impairment may partly explain the associations between right hemisphere damage and decreased ability to perform certain analytic and linguistic tasks.

Adult↗
PubMed1987

Auditory P3 correlates of phonemic and semantic processing.

Auditory evoked potentials were recorded in twelve healthy subjects using phonemic and semantic word tasks. The late positive component (P3), analogous to tonal P300, varied as a function of cognitive task with increased latency and amplitude associated with semantic processing. These data are consistent with levels of processing theories in which semantic analysis is associated with a greater elaboration of stimulus evaluation.

Adult↗
PubMed1986

Hypometria with hemispatial and limb motor neglect.

A patient with a haemorrhage in the right mesial frontal lobe exhibited hypokinesia, bradykinesia and a hypometric movement disorder of his contralateral limbs. This movement disorder was characterized by reduced amplitude of otherwise normally formed movements (hypometria). In addition, the left limb hypokinesia improved with placement of the left forelimb into right hemispace (hemispatial motor neglect). We postulate that the hypokinesia, bradykinesia and hypometria were induced by reduction in activation of forebrain dopaminergic and basal ganglion motor systems, which in conjunction with the supplementary motor area are critical for setting the activational level for motor output.

Analysis of Variance↗
PubMed1986

The right hemisphere: neuropsychological functions.

In the past two to three decades, clinicians and neuroscientists have been studying the functions of the right hemisphere. Neither hemisphere seems to be dominant in the absolute sense. Each appears to be specialized and is dominant for different functions. However, most functions require the cooperation of both hemispheres. When one is damaged, the other can often compensate for the damaged one. Lesions of the left hemisphere are associated with language (speech, reading, and writing) and praxic disorders, and lesions of the right hemisphere can result in visuospatial, attentional, and emotional disorders. The authors review some of the major behavior disorders associated with right hemisphere dysfunction and concentrate on three major types of disorders--visuospatial, attentional, and emotional. Although not all the behavioral defects associated with right hemisphere damage can be subgrouped under these three types, they are the ones most often associated with right hemisphere lesions.

Agnosia↗
PubMed1985

Preinduction cervical ripening with prostaglandin E2 (Prepidil) gel.

The effect of preinduction cervical ripening with Prepidil, a commercially prepared prostaglandin E2 gel (0.5 mg), on the outcome of induction of labor with intravenous oxytocin was investigated. Fifty-nine pregnant women were randomized either to receive intracervical application of the gel or to undergo sham application. Compared to control subjects, patients in the group given Prepidil had significant increases in cervical Bishop scores, shorter induction-to-delivery intervals, lower maximum doses of oxytocin, and fewer days of induction. Systemic side effects were minimal, but 37% (11 of 30) of the gel-treated patients experienced labor prior to receiving oxytocin and 20% (six of 30) were actually delivered during the 12-hour ripening period. No differences in route of delivery or fetal outcome were found between the two groups.

Adult↗
PubMed1985

Processing of faces by patients with unilateral hemisphere lesions. I. Dissociation between judgments of facial affect and facial identity.

In this study, right-hemisphere-damaged (RHD) subjects performed significantly worse than LHD and NHD controls across a series of seven facial identity and facial affect tasks. Even when the patient groups were statistically equated on a measure of visuoperceptual ability, the RHD group remained impaired on three emotional tasks--naming, picking, and discriminating emotional faces. These findings suggest that the defects shown by RHD patients on facial affect tasks cannot be solely attributed to defects in visuoperceptual processing and that the right-hemisphere superiority for processing facial affect exists above and beyond its superiority for processing facial identity.

Affect↗
PubMed1985

Aneurysms of the abdominal aorta: a 20-year study.

One hundred and eighty-eight patients in whom the diagnosis of aneurysm of the abdominal aorta (AAA) was established after 1 January 1960 were followed until their deaths or to 31 December 1979. By the actuarial method, the cumulative 5-year risk of an intact aneurysm progressing to rupture was 35%; the observed 5-year survival rate for patients who had medical management for intact AAA was 30%, for patients who had elective surgery for AAA 74%, for patients who had emergency surgery for ruptured AAA 35%, and for those who did not have surgery for ruptured AAA 0%. Comparison of the non-operated and electively-operated groups of patients showed that the former was disproportionately weighted with older higher-risk patients, suggesting that the difference in survival rates for the two groups might be a reflection of patient selection rather than of surgical intervention. Comparison of the cumulative 5-year risk of rupture of an intact AAA with the cumulative 5-year mortality rate associated with elective surgery for intact AAA showed that elective surgery for intact AAA might be expected to result in a reduction in the cumulative 5-year mortality rates of patients with intact AAA.

Aged↗
PubMed1985

Directional hypokinesia: prolonged reaction times for leftward movements in patients with right hemisphere lesions and neglect.

Patients with hemispatial neglect perform activities poorly in the hemispace contralateral to the lesion. We postulate that hemispatial neglect induced by right hemisphere lesions may be associated with a directional hypokinesia: initiation of movements toward the hemispace contralateral to the lesion is affected more than movements toward the lesion. We tested 6 patients with hemispatial neglect caused by right hemisphere damage, 7 with left hemisphere damage and no neglect, and 12 controls. Patients with left hemispatial neglect initiated responses to left hemispace more slowly than toward right hemispace.

Adult↗
PubMed1984

Dissociation between the processing of affective and nonaffective faces: a case study.

In this report we describe a patient with a right-hemisphere lesion who showed a dissociation between the processing of affective and nonaffective faces. Although he performed normally on neutral facial tasks, he was impaired in naming and pointing to facial expressions. This dissociation is discussed in terms of four possible mechanisms: (a) a high-level visuoconfigurational defect; (b) an associative agnosic type of defect for facial expressions; (c) a specific "activation" defect; and (d) a visual-verbal disconnection resulting in an anomic type of defect for facial expressions.

Affect↗
PubMed1984

Pseudoneglect in a patient with partial callosal disconnection.

Each hemisphere may not only be responsible for processing stimuli from the contralateral sensory systems and for programming movements of the contralateral hand, but may also be important for mediating attention-intention within the contralateral hemispace. If each hemisphere mediates attention-intention within contralateral hemispace, both hemispheres must work in concert especially when an arm is crossed and used in opposite hemispace. If both hemispheres did not work together, the directional bias of each hemisphere would become manifest and induce the contralateral extremity to err toward its own hemispace, inducing pseudoneglect . To test this hypothesis, we examined a patient who had a partial callosal disconnection. In trying visually and somaesthetically to bisect lines with her left hand in right hemispace, the patient made systematic errors to the left; in bisecting lines in left hemispace with her right hand, she made systematic errors to the right. The patient also made less dramatic systematic errors even when a hand was used in its own hemispace, which suggests that each hemisphere mediates attention-intention within and towards the contralateral hemispace.

Adolescent↗
PubMed1984

Comprehension of affective and nonaffective prosody.

We studied patients with damage of either the right (RHD) or left hemisphere (LHD) and control subjects to determine whether the RHD patients had a global or limited prosodic defect. Compared with LHD patients and controls, RHD subjects had decreased comprehension of emotional prosody. Both LHD and RHD groups had more impaired comprehension of propositional prosody than controls, but the RHD and LHD groups did not differ. The right hemisphere, therefore, seems to be dominant for comprehending emotional prosody but not propositional prosody.

Adult↗
PubMed1983

Performance on hemispatial pointing task by patients with neglect syndrome.

Five patients with left hemispatial neglect and five aphasic control subjects were given a hemispatial pointing task. They were instructed to point to an imaginary point in space perpendicular to the midline of the chest. Right hemisphere-damaged subjects with neglect deviated more into the hemispace ipsilateral to the lesion than left hemisphere-damaged controls. This task did not require sensory input from left hemispace, and the defective performance cannot be attributed to sensory inattention or to impaired gaze or memory. The finding is compatible with hemispatial akinesia.

Adult↗
PubMed1983

Wrist dimensions: correlation with median sensory latencies.

A serendipitous observation that many individuals with carpal tunnel syndrome have square wrists led to this study which correlates wrist dimensions with median sensory latencies. Results suggest that the squarer the wrist the longer the latencies.

Adult↗