Inhibitory control of attention declines more than working memory during normal aging.

Changes in frontostriatal systems are believed to reduce the efficiency of executive cognitive functions during normal aging, especially the inhibitory control of attentional and behavioral responses. To characterize changes during normal aging in sensorimotor, working memory and inhibitory attentional systems, we tested 20 healthy elderly subjects (age 65-80) and 28 young adults (age 18-34) using oculomotor paradigms. Visually guided saccades of elderly subjects showed decreased peak velocity and increased reaction time, but not reduced accuracy, indicating selective age-related declines in sensorimotor systems. In an oculomotor working memory task, memory for spatial location information in elderly subjects was as accurate as in young adults. In contrast, elderly subjects demonstrated a significantly reduced ability to voluntarily inhibit eye movements toward flashed targets on an antisaccade task. These findings indicate changes in frontostriatal systems during normal aging that adversely affect volitional inhibitory processes but spare encoding and retrieval components of spatial working memory.

Cortical networks subserving pursuit and saccadic eye movements in humans: an FMRI study.

High-field (3 Tesla) functional magnetic resonance imaging (MRI) was used to investigate the cortical circuitry subserving pursuit tracking in humans and compare it to that for saccadic eye movements. Pursuit performance, relative to visual fixation, elicited activation in three areas known to contribute to eye movements in humans and in nonhuman primates: the frontal eye field, supplementary eye field, and intraparietal sulcus. It also activated three medial regions not previously identified in human neuroimaging studies of pursuit: the precuneus and the anterior and posterior cingulate cortices. All six areas were also activated during saccades. The spatial extent of activation was similar for saccades and pursuit in all but two regions: spatial extent was greater for saccades in the superior branch of the frontal eye field and greater for pursuit in posterior cingulate cortex. This set of activations for smooth pursuit parallels the network of oculomotor areas characterized in nonhuman primates and complements recent studies showing that common cortical networks subserve oculomotor functions and spatial attention in humans.

Dorsal cortical regions subserving visually guided saccades in humans: an fMRI study.

Neurophysiological studies in non-human primates have identified saccade-related neuronal activity in cortical regions including frontal (FEF), supplementary (SEF) and parietal eye fields. Lesion and neuroimaging studies suggest a generally homologous mapping of the oculomotor system in humans; however, a detailed mapping of the precise anatomical location of these functional regions has not yet been achieved. We investigated dorsal frontal and parietal cortex during a saccade task vs. central fixation in 10 adult subjects using functional magnetic resonance imaging (fMRI). The FEF were restricted to the precentral sulcus, and did not extend anteriorly into Brodmann area 8, which has traditionally been viewed as their location in humans. The SEF were located in cortex along the interhemispheric fissure and extended minimally onto the dorsal cortical surface. Parietal activation was seen in precuneus and along the intraparietal sulcus, extending into both superior and inferior parietal lobules. These findings localize areas in frontal and parietal cortex involved in saccade generation in humans, and indicate significant differences from the macaque monkey in both frontal and parietal cortex. These differences may have functional implications for the roles these areas play in visuomotor processes.

Marking of verb transitivity by Hebrew-speaking children.

The study examines children's command of transitivity permutations in Hebrew, where a change in verb-argument syntax entails a change in verb-morphology. 30 children aged two, three and eight were required to produce existing and novel Hebrew verbs differing in transitivity. Younger children showed a good grasp of the syntax and semantics, but not the morphological marking of transitivity, three-year-olds did much better, and eight-year-olds produced mainly adult-like responses. Results were higher on existing verbs than on novel forms. Direction of change had little effect with existing verbs, but with novel verbs success was much higher in changing intransitive to transitive forms than the converse. Some alternations proved easier than others, e.g. intransitive activity verbs in the basic pa'al verb-pattern yielded more causative hif'il forms than intransitive inchoative verbs in the nif'al pattern. Findings throw light on the development of derivational morphology, item-based versus class-based learning, and the impact of lexical productivity and language-particular properties on acquisition.

Severity of illness and the teaching hospital.

In the current environment of cost containment pressures on health care providers, teaching hospitals are facing increased financial risks that could jeopardize their special role in the health care delivery system. One of these risks is that the Medicare prospective payment system does not adequately account for severity of illness. Whether teaching hospitals treat a case mix of patients with more severe illness than do nonteaching hospitals was tested in the study reported here using two severity measures, Horn's severity of illness index and Gonnella's "disease staging." Teaching hospitals were found to treat a significantly greater proportion of severely ill patients than community hospitals, especially when measured by the severity of illness index. Differences in case mix of severity of illness among hospitals can have a significant impact on patient care costs, which may not be adequately met by a reimbursement system based on diagnosis related groups. Hospital managers can use severity of illness measures to assess the resource needs of patients and the practice patterns of physicians. If severity of illness measures help describe the special burden of treatment that teaching hospitals bear, they should be used to establish the case for adequate financial support.

Delayed pulmonary dysfunction in head-injured patients.

Intracranial pressure (ICP), cardiopulmonary function, and the degree of neurological dysfunction were measured in 13 patients with serious head injury to determine the relationship of these indices to the development of delayed pulmonary dysfunction. All patients had serious isolated head injury with Glasgow Coma Scale scores of 7 or less 6 hours after injury and elevated ICP at the time of admission to the protocol. Three patients developed arterial pO2 of less than or equal to 80 torr despite the initiation of elevated inspired oxygen fraction (FIO2 greater than or equal to 0.5) and positive end expiratory pressure (greater than or equal to 5 cm H2O. One of these three patients had a decline in neurological function, quantified by the Albany Head-Injury Watch Sheet, associated with hypoxemia. The only patients who developed intrapulmonary shunt fractions of more than 15% were five patients who had increased pulmonary vascular resistance (PVR) and elevated or increasing cardiac index, suggesting persistent perfusion to areas of the lung which normally are hypoperfused due to hypoxic pulmonary vasoconstriction. This mismatching of the distribution of ventilation and perfusion was confirmed using the multiple inert gas elimination technique in two patients with an increased shunt fraction. Unperfused gas exchange units were also found to be present, as confirmed by an abnormal multiple inert gas elimination techniques, high PVR and dead space/tidal volume ratio (VD/VT), and low extravascular lung water. Abnormalities of ICP and cerebral perfusion pressure could not be correlated with changes in any of the cardiopulmonary functions studied.

Systemic thermotherapy (whole body hyperthermia).

This is an article reviewing the literature and our experience to date (six months) in the treatment of cancer using whole body hyperthermia in the first 60 patients. WBHT is an effective method of treating cancer. Patients were treated for a total of eight hours, 180 degrees F for two hours. WBHT was induced by means of two high-flow water filled blankets. Toxicity included fatigue, nausea, diarrhea and first degree burns. There was no evidence of visceral damage. There were no mortalities during the procedure. Objective responses were 50%, subjective responses were 65%. The literature demonstrates and our study confirms that under closely monitored conditions, WBHT is a feasible, safe and active anti-cancer therapy. WBHT may be safely used as an adjunct to other active cancer therapies including X-ray therapy and chemotherapy.