Introduction to forum on impact factors.
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Bibliometrics↗
Biomedical subjects
H A Buchtel
Publications and source records attributed to H A Buchtel.
Left and right hemisphere contributions to physiognomic and verbal discrimination.
The relative contributions of the right- and left-temporal lobes in rapid recognition of faces and letters were studied in patients with anterior right- or left-temporal lobe excisions and a matched control group. On the basis of findings in patients with unilateral and bilateral brain damage, it was hypothesized that left hemisphere damage would not change the reaction time of letters analyzed by the right hemisphere and that right hemisphere damage would not change the reaction time of faces analyzed by the left hemisphere. The hypothesis was supported for letters but not for faces. Patients in the right-temporal group, particularly those with large hippocampal removals, were slow to recognize faces in both visual fields. Two possible explanations for the findings with faces are explored: One holds that right hemisphere mechanisms are involved even when a face is presented to the left hemisphere for rapid recognition; the other holds that specialized encoding is carried out by the right hemisphere during learning, with the encoded template then being used by each hemisphere independently.
Adult↗
Presurgery expectations, postsurgery satisfaction, and psychosocial adjustment after epilepsy surgery.
PURPOSE: The medical benefits of epilepsy surgery are well documented, but the psychosocial consequences of surgery have received less attention. This is especially true of the roles of expectations and satisfaction in postsurgery functioning. The present study was designed to examine the relationships between expectation, satisfaction with surgery, and psychosocial functioning in patients and their significant others before and after epilepsy surgery. METHODS: The neuropsychology findings of 79 patients undergoing epilepsy surgery were examined from assessments made before, 2 months after, and 1 year after anterior temporal lobectomy (ATL) was performed. The Minnesota Multiphasic Personality Inventory (MMPI) and the Washington Psychosocial Seizure Inventory (WPSI) were used to assess psychosocial functioning. A subset of 32 patients and their significant others were followed prospectively with an additional semistructured interview to assess expectations for and satisfaction with surgery outcome. RESULTS: Before surgery, patients showed considerable problems with psychosocial adjustment. After surgery, patients in the seizure-free group showed improvements on the psychosocial measures at both follow-ups, whereas patients with continued seizures showed improvement at the 2-month follow-up and then a decline to baseline or worse at the time of the 1-year follow-up. Subjects who were studied prospectively had high presurgery expectations for seizure elimination. After surgery, subjects whose expectations were met reported high satisfaction whereas subjects whose expectations were not met reported low satisfaction. Satisfaction with surgery was associated with better psychosocial functioning. CONCLUSIONS: Such data help elucidate the ways in which successful epilepsy surgery results in improved psychosocial functioning. The results identify ways to increase the likelihood that both patients who are seizure-free and those with reduced seizure frequency may benefit from surgery.
Adaptation, Psychological↗
Absence of normal activation of the left anterior fusiform gyrus during naming in left temporal lobe epilepsy.
Patients with left temporal lobe epilepsy (TLE) often have impaired naming. We studied 13 patients with left TLE and 10 healthy control subjects with [(15)O]H2O PET during visual confrontation naming. Statistical mapping detected multiple regions of significant cerebral blood flow increases within individuals. The left fusiform gyrus was activated in nine healthy subjects, but only in two patients with TLE (a significant difference, p < 0.001). Other activation sites were more variable in healthy subjects and those with TLE. Impaired naming ability may be associated with a lack of increased cerebral blood flow in the left fusiform gyrus in TLE.
Adolescent↗
Electrocerebral recovery during the intracarotid amobarbital procedure: influence of interval between injections.
PURPOSE AND METHODS: During the intracarotid amobarbital procedure (IAP) at the University of Michigan, continuous scalp EEG monitoring guides the timing for presentation of memory items and postinjection testing. Most of our patients have undergone bilateral injections. The interval between injections varied from 22 to 60 min, depending on the test and recovery time, as well as the time to catheterize the second side. After noting a trend toward prolonged electrographic recovery following the second injection, we tested our clinical impression that recovery of the second hemisphere may be influenced by (a) the time between injections and (b) which hemisphere is injected first (epileptogenic or nonepileptogenic). To study these questions, we analyzed EEG recovery data from 48 consecutive IAPs. Approximately half the patients had the epileptogenic side injected first. RESULTS: We found that (a) electrographic recovery after the second injection is prolonged if the interval between bilateral injections is less than 40 minutes and (b) electrographic recovery is more rapid after injection of the epileptogenic hemisphere. CONCLUSIONS: We now recommend waiting at least 45 min between injections. The pathophysiology of more prolonged amobarbital effect on the nonepileptogenic hemisphere than on the epileptogenic hemisphere remains unclear.
Amobarbital↗
How gender affects psychological adjustment one year after coronary artery bypass graft surgery.
This research investigated gender differences in psychological adjustment among patients (112 males, 39 females) one year after coronary artery bypass graft surgery (CABG). Information regarding post-CABG depression, non-cardiac chronic conditions, and socioeconomic variables were obtained from a survey. Additional cardiac, surgical, and demographic data were retrieved from a hospital computer database. Women were more likely than men to experience postoperative depression, attributable to their poor health. Depression one year post-CABG was predicted by non-cardiac chronic illnesses, postoperative fatigue and shortness of breath and socioeconomic status.
Adaptation, Psychological↗
Effects of stimulus source and intensity on covert orientation to auditory stimuli.
Normal subjects showed costs and benefits of informative auditory spatial cues with auditory targets in RT tasks when stimulus intensity was low, or when the stimuli were presented monaurally through headphones. These findings imply that attention to auditory stimuli, like attention to visual or tactile stimuli, can be shifted spatially in detection tasks, and that covert orienting to auditory stimuli occurs in conditions favoring the intention to orient the head to a sound source. According to this view, orienting of attention to auditory stimuli, as well as to visual and tactile stimuli, is linked functionally to mechanisms controlling overt orienting movements that increase stimulus identification.
Adolescent↗
Tactile rod bisection: hemispheric activation and sex differences.
Blindfolded subjects estimated with either hand the center of rods positioned in either left or right hemispace. In one condition, they also performed a concurrent verbal task. Bias and variability of bisection settings were the dependent variables. Bisections performed in left hemispace were biased to the left of true center, more so when the left hand was used. In contrast, bisections performed in right hemispace were biased rightward, more so when the right hand was used. There were no significant differences in variability of bisections in any condition. Interactions of hand with hemispace in which the task was performed differed for the two sexes. Moreover, the secondary verbal task had no effect on either measure. We conclude that of several factors that may underlie bisection biases, attention was the most relevant.
Adult↗
Advance directives: making them more available to hospitals patients.
This article details methods developed to facilitate patients' understanding and execution of an advance directive (e.g., living will, treatment preferences, and durable power of attorney for healthcare). The approach takes advantage of the computerization of patient records, using automatically generated e-mail messages sent to an advance directives consultation team.
Advance Directives↗
Language mapping in epilepsy patients undergoing dominant hemisphere anterior temporal lobectomy.
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Brain Mapping↗
Verbal fluency and positron emission tomographic mapping of regional cerebral glucose metabolism.
Impairment in verbal fluency (VF) has been a consistently reported clinical feature of focal cerebral deficits in frontal and temporal regions. More recent behavioral activation studies with healthy control subjects using positron emission tomography (PET), however, have noted a negative correlation between performance on verbal fluency tasks and regional cortical activity. To see if this negative relationship extends to steady-state non-activation PET measures, thirty-three healthy adults were given a VF task within a day of their 18F-2-fluoro-2-deoxy-D-glucose PET scan. VF was found to correlate positively with left temporal cortical region metabolic activity but to correlate negatively with right and left frontal activity. VF was not correlated significantly with right temporal cortical metabolic activity. Some previous studies with normals using behavioral activation paradigms and PET have reported negative correlations between metabolic activity and cognitive performance similar to that reported here. An explanation for the disparate relationships that were observed between frontal and temporal brain areas and VF might be found in the mediation of different task demands by these separate locations, i.e., task planning and/or initiation by frontal regions and verbal memory by the left temporal area.
Adult↗
Cerebral control of directed visual attention and orienting saccades.
The object of this experiment was to identify the contribution of the frontal and parietal lobes to the control of visual attention and voluntary saccades. A symbolic spatial cue (arrow) was used to indicate validly or invalidly the location of a visual target located to the left or right of the cue. Manual reaction time and reaction time to initiate a saccade to the target were measured. Patients with damage to the left frontal lobe (n = 6), right frontal lobe (n = 7) and right parietal lobe (n = 7) were compared with normal control subjects (n = 20). A sex difference was found for the right cerebral hemisphere patients in the manual reaction time data. Right parietal males and right frontal females showed an overall elevation in manual reaction time, reflecting an inability to maintain a normal level of visual arousal and/or motor activation. Conversely, right frontal males and right parietal females were not influenced significantly by cue validity, suggesting that they were unable to direct visual attention in a covert manner. All subjects showed a normal effect of cue validity on saccade reaction time. Thus the cortical areas studied do not appear to be necessary for directing visual attention with a saccade. Cue validity, however, affected saccade amplitude, especially in the left visual field of patients with right hemisphere damage. The cue validity effect depended both on the sex of the subject and the anterior/posterior location of damage in the right hemisphere. Damage to the right frontal lobe resulted in an 'under' reaction to the spatial cues, especially in the male patients. Saccades were smaller than normal following the valid cues, but larger than normal following the invalid cues. The effect was opposite following damage to the right parietal lobe. In this case, saccade amplitude reflected an 'over' reaction to the spatial cues, especially in the female patients. Saccades were larger than normal following valid cues and smaller than normal following invalid cues.
Analysis of Variance↗
Spatial attentional shifts: further evidence for the role of polysensory mechanisms using visual and tactile stimuli.
Normal subjects performed simple reaction time responses to lateralized visual target stimuli (Experiment 1) and lateralized tactile target stimuli (Experiment 2). In each experiment, the lateralized targets were preceded at one of four intervals by a visual or tactile cue located on the same (valid cue), or opposite (invalid cue) side, or on both sides (neutral cue). The validity of the visual and tactile cues influenced the speed of response to either target stimulus. These findings, together with those previously reported (Buchtel and Butter, Neuropsychologia 26, 499-509, 1988), are consistent with the view that intra- and inter-modal spatial cueing is effective with modalities that are linked to orienting systems in which movements of the sensory array serve to improve sensory analysis.
Adult↗
Auditory agnosia: apperceptive or associative disorder?
Neuropsychological testing of a patient with auditory agnosia showed that certain difficulties in the initial analysis of sounds may be the cause of his inability to understand spoken words and other sounds. Abnormalities included a slow reaction time to brief auditory stimuli (but not to equally brief visual stimuli or to longer auditory stimuli) and the need for approximately 1/4 sec of silence between two tones before the patient was able to hear them as separate. He could identify words and word associations if he was able to view the object whose name or word associate he was hearing. The findings imply that this patient's deficit in comprehending speech was probably apperceptive rather than associative in origin.
Agnosia↗
Positron emission tomographic scan investigations of Huntington's disease: cerebral metabolic correlates of cognitive function.
Fifteen drug-free patients with early to mid-stage Huntington's disease (HD) were evaluated with positron emission tomographic (PET) scans of 18F-2-fluoro-2-deoxy-D-glucose uptake and quantitative measures of neurological function, learning, memory, and general intelligence. In comparison with a group of normal volunteers, the HD patients showed lower metabolism in both caudate (p less than 0.001) and putamen (p less than 0.001) on PET scans. A significant and positive relationship was found between neuropsychological measures of verbal learning and memory and caudate metabolism in the patient group but not in the normal group. Visual-spatial learning did not reflect a similar pattern, but performance intelligence quotient was positively related to both caudate and putamen metabolism in the HD group. Vocabulary level was unrelated to either brain structure. Discussion focuses on these and other observed brain-behavior relationships and on the implications of these findings for general behaviors such as those involved in coping and adaptation.
Adult↗
Spatial attentional shifts: implications for the role of polysensory mechanisms.
Simple reaction times to lateralized visual (Experiment 1) or auditory (Experiment 2) targets were studied in normal subjects. The targets were preceded by a visual or auditory cue located on the same (valid cue), or opposite (invalid cue) side as the subsequent target, or on both sides (neutral cue), with one of four cue target intervals. The validity of visual and auditory cues influenced the speed of response to the visual target but not to the auditory target. It is hypothesized that cross-modal cueing of spatial position works only with modalities for which a movement (e.g. saccade) leads to improved sensory analysis.
Adult↗
Long-lasting memory deficits in children recovered from Reye's syndrome.
Twenty-six children, ages 7-18 years, were tested for possible memory impairments following Reye's syndrome (RS). The RS group was matched to a normal control group on race, age, SES, and estimated IQ. The Wechsler Memory Scale (with delayed recall) and two depth-of-processing tests were administered. For the control group, the mean MQ-IQ difference was +2, while the MQ-IQ difference for the RS group was -14. This proved to be highly significant. Short-term memory and long-term memory scores were significantly lower for the RS group, with verbal memory tasks being most affected.
Adolescent↗
Impairments in orienting to visual stimuli in monkeys following unilateral lesions of the superior sulcal polysensory cortex.
Monkeys were tested for head and eye orientation to illuminated lamps in a hemisphere before and after serial, unilateral lesions of the polysensory superior temporal cortex (STS) or control lesions. Following STS lesions they were impaired in orienting to contralateral lamps; this impairment was more severe and persistent when a ipsilateral stimulus in the mirror-image position was simultaneously presented. These findings, together with deficits in manual reaching and grasping observed following STS lesions, support the view that the STS is part of a polysensory system controlling attention and exploratory movements.
Animals↗