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Biomedical subjects

C C Duncan

Publications and source records attributed to C C Duncan.

At least 19 recordsLinked to original sources
PubMed1998

Sex differences in seasonal variations in P300.

Previous reports of seasonal variations in P300 were based on cross-sectional observations of subjects tested at different times of the year. In this study, we tested three groups of subjects in each of two seasons: winter and spring, spring and summer, and summer and winter. We found winter or spring maxima in auditory and visual P300 and visual slow wave. This pattern of results, with the amplitude of P300 being inversely related to the amount of sunlight in a season, supports the hypothesis that the allocation of processing resources varies across the seasons. Our results also suggest a trend for an increased sensitivity of women, as compared with men, to seasonal influences on P300. Although our findings do not provide strong evidence that P300 varies systematically as a function of season, seasonal factors appear to affect cognitive processing (as indexed by P300) differentially in men and women.

Adolescent↗
PubMed1998

Minimal head trauma in children revisited: is routine hospitalization required?

OBJECTIVE: Children with a question of occult head injury are routinely hospitalized despite having both normal central nervous system (CNS) and computed tomographic (CT) scan examinations. We determined the incidence of significant CNS morbidity after occult head injury to determine whether or not hospital admission was necessary in children after minimal head trauma. METHODS: We reviewed the records of children admitted to a level I trauma center with a question of closed head injury, an initial Glasgow Coma Scale equal to 15, a normal neurologic exam, and a normal head CT scan. Children with associated injuries requiring admission were excluded. The endpoints were deterioration in CNS exam, new CT findings, and the need for a prolonged hospital stay. RESULTS: Sixty-two patients were studied with a mean age of 7 years (range, 1 month to 15 years), and 65% were male. The primary mechanisms of injury were fall (45%) and vehicular crash (23%). The mean injury severity score was 4 +/- 2. The mean length of stay was 1.2 days (range, 1 to 3 days). Prolonged hospitalization occurred in 9 patients (15%). No child developed significant CNS sequelae warranting hospital admission. Total charges for these hospitalizations were $177 874. CONCLUSIONS: Children undergoing emergency department work-up of occult head injury, who have a normal CNS exam and a normal head CT scan, do not seem to be at risk for significant CNS sequelae. These patients can be discharged home with parental supervision and avoid unnecessary and costly hospitalization.

Adolescent↗
PubMed1996

Circadian profiles of cortisol, prolactin, and thyrotropin in seasonal affective disorder.

To determine whether circadian profiles of various plasma hormones are abnormal in patients with winter seasonal affective disorder (SAD), we obtained 24-hour profiles of plasma cortisol, prolactin, and thyrotropin in subsets of a sample of 22 depressed patients with SAD on and off light therapy and in subsets of a sample of 24 normal controls. Cortisol levels did not differ between patients and controls, and levels in patients were not affected by light therapy. Prolactin levels were lower in patients than in controls throughout the day (p < 0.03) but were unaffected by light therapy. Independent of patient vs. control status, prolactin levels were higher in women than in men throughout the day (p < 0.003). Thyrotropin levels were no different in patients and controls, but levels in patients were lower following light therapy (p < 0.05).

Adult↗
PubMed1996

Three cases of symptom change in Tourette's syndrome and obsessive-compulsive disorder associated with paediatric cerebral malignancies.

OBJECTIVE: To correlate behaviour manifestations with tumour location in three children who had Gilles de la Tourette's syndrome (GTS), obsessive-compulsive disorder (OCD), and primary cerebral malignancies. METHOD: Cases were ascertained from a chart review in a GTS and OCD specialty clinic. For each case the temporal progression of change in neuropsychiatric symptoms was qualitatively correlated with radiographic documentation of tumour progression. RESULTS: The change in symptom severities during tumour progression and treatment, together with prior neurobiological studies of GTS, suggest that the ventral striatum, corpus callosum, thalamus, and midbrain are potentially important neural substrates in the formation or modulation of tic symptoms. The limbic system, including the hypothalamus and cingulate, and the caudate nucleus, seem to be important in the neurobiology of OCD. All structures are neuroanatomically and functionally related to the corticostriato-thalamocortical circuitry that is thought to subserve symptom generation in both GTS and OCD. CONCLUSION: Although the malignancies were not likely to have caused the tic and OCD symptoms in these children, the locations of these intracranial lesions provide important clues in identifying brain regions that may contribute to the determination of tic and OCD severities.

Brain↗
PubMed1996

Neurodevelopmental outcome at 36 months' corrected age of preterm infants in the Multicenter Indomethacin Intraventricular Hemorrhage Prevention Trial.

OBJECTIVES: Low-dose indomethacin has been shown to prevent intraventricular hemorrhage (IVH) in very low birth weight neonates, and long-term neurodevelopmental follow-up data are needed to validate this intervention. We hypothesized that the early administration of low-dose indomethacin would not be associated with adverse cognitive outcome at 36 months' corrected age (CA). METHODS: We enrolled 431 neonates of 600 to 1250 g birth weight with no IVH at 6 to 12 hours in a randomized, prospective trial to determine whether low-dose indomethacin would prevent IVH. A priori, neurodevelopmental follow-up examinations, including the Stanford-Binet Intelligence Scale and Peabody Picture Vocabulary Test-Revised, and standard neurologic examinations were planned at 36 months' CA. RESULTS: Three hundred eighty-four of the 431 infants survived (192 [92%] of 209 infants receiving indomethacin versus 192 [86%] of 222 infants receiving saline), and 343 (89%) children were examined at 36 months' CA. Thirteen (8%) of the 166 infants who received indomethacin and 14 (8%) of 167 infants receiving the placebo were found to have cerebral palsy. There were no differences in the incidence of deafness or blindness between the two groups. For the 248 English-monolingual children for whom IQ data follow, the mean gestational age was significantly younger for the infants who received indomethacin than for those who received the placebo. None of the 115 infants who received indomethacin was found to have ventriculomegaly on cranial ultrasound at term, compared with 5 of 110 infants who received the placebo. The mean +/- SD Stanford-Binet IQ score for the 126 English-monolingual children who had received indomethacin was 89.6 +/- 18.92, compared with 85.0 +/- 20.79 for the 122 English-monolingual children who had received the placebo. Although maternal education was strongly correlated with Stanford-Binet IQ at 36 months' CA, there was no difference in educational levels between mothers of the infants receiving indomethacin and the placebo. CONCLUSIONS: Indomethacin administered at 6 to 12 hours as prophylaxis against IVH in very low birth weight infants does not result in adverse cognitive or motor outcomes at 36 months' CA.

Cerebral Hemorrhage↗
PubMed1995

Antenatal steroids, delivery mode, and intraventricular hemorrhage in preterm infants.

OBJECTIVE: The relationship between antenatal steroids, delivery mode, and early-onset intraventricular hemorrhage was examined in very-low-birth-weight infants. STUDY DESIGN: A total of 505 preterm infants (birth weight 600 to 1250 gm) were enrolled in a multicenter, prospectively randomized, controlled trial evaluating the efficacy of postnatal indomethacin to prevent intraventricular hemorrhage. All infants had echoencephalography between 5 and 11 hours of life. RESULTS: Seventy-three infants had intraventricular hemorrhage within the first 5 to 11 hours (mean age at echoencephalography 7.5 hours). Four hundred thirty-two infants did not have early intraventricular hemorrhage. There was less antenatal steroid treatment (19% vs 32%, p = 0.03) and more vaginal deliveries (71% vs 45%, p < 0.0001) in the group with early intraventricular hemorrhage. Of 152 infants who received antenatal steroids, those delivered by cesarean section had significantly less early-onset intraventricular hemorrhage than did those delivered vaginally (4% vs 17%, p = 0.02). Of the 353 not exposed to antenatal steroids, 10% of infants delivered by cesarean section and 22% delivered vaginally had early intraventricular hemorrhage (p = 0.003). CONCLUSION: These data are the first to suggest that both antenatal steroids and cesarean section delivery have an important and independent role in lowering the risk of early-onset intraventricular hemorrhage.

Cerebral Hemorrhage↗
PubMed1995

Neuroendoscopic laser-assisted ventriculostomy of the third ventricle.

Hydrocephalus is caused by an imbalance between the production and absorption of cerebrospinal fluid. Ventriculostomy of the third ventricle now is an acceptable treatment alternative for this problem. This procedure reduces costs over the course of the illness because the patient does not require subsequent shunt revisions throughout his or her life. The specialized care and the fear associated with the dependency on mechanical hardware also are eliminated if shunt placement is avoided. Postoperative complications may include increased intracranial pressure, bleeding, infection, and pain.

Child↗
PubMed1995

Diagnosis-related group refinement with diagnosis- and procedure-specific comorbidities and complications.

Diagnosis-related groups have been revised through more refined uses of secondary diagnoses. Under the refined diagnosis-related groups, patients are distinguished with respect to classes of secondary diagnoses that are disease- and procedure-specific. Each class represents a different level of utilization for a given principal diagnosis or surgical procedure. The refined system was evaluated with national data from the Medicare program. Estimates of hospital costs and utilization based on refined diagnosis-related groups were more precise than those based on unrefined diagnosis-related groups. This approach to diagnosis-related group refinement does not represent a radical departure from the current diagnosis-related group framework and does not require new data collection efforts. Moreover, a payment system based on the refined model is less affected by the ordering of the diagnoses than under the existing diagnosis-related group system. How the refined diagnosis-related group framework can accommodate future refinements at all levels of the classification scheme is also discussed.

Adult↗
PubMed1995

Costs of potential complications of care for major surgery patients.

We examined computerized hospital discharge abstract data from 372,680 major surgery patients admitted to 404 California acute care hospitals in 1988 to identify potential complications of care. At least one potential in-hospital complication occurred for 10.8% of patients. Patients with complications were older and more likely to die in-hospital (9.4% compared to 1.0%, P < 0.0001). On average, patients with complications had longer stays (13.5 versus 5.4 days, p < 0.0001) and higher total charges ($30,896 versus $9,239, p < 0.0001). After adjusting for demographic, clinical, and hospital factors, patients with potential complications averaged $16,023 higher total hospital charges than uncomplicated patients. Complications were associated with 96.6% (95% confidence interval = 95.2%, 98.0%) higher hospital charges after adjusting for these factors. Across all patients, complications were related to over $647 million in additional total hospital charges for these major surgery patients.

California↗
PubMed1994

Sleep in fall/winter seasonal affective disorder: effects of light and changing seasons.

Disturbances of sleep are a hallmark of seasonal affective disorders (SAD), as they are of other mood disorders. Fall/winter SAD patients most often report hypersomnia. Among responses of 293 SAD patients on a symptom questionnaire, complaints of winter hypersomnia (80%) greatly exceeded insomnia (10%), hypersomnia plus insomnia (5%), or no sleep difficulty (5%). Increased sleep length in fall/winter is not unique to SAD. Among 1571 individuals across four latitudes surveyed at random from the general population, winter sleep increases of < or = 2 hr/day relative to summer were reported by nearly half. However, hypersomnia had a low correlation (r = 0.29) with the total number of other SAD symptoms that were reported in this sample. Ten SAD patients kept daily sleep logs across 1 yr that showed increases in fall and winter (sleeping most in October; least in May) whose maximum averaged 2.7 hr per day more weekend sleep than in spring and summer. These winter increases might have been somewhat attenuated since most received light therapy during part of the winter. Nocturnal EEG recordings of depressed SAD patients in winter showed decreased sleep efficiency, decreased delta sleep percentage, and increased REM density (but normal REM latency) in comparison with recordings: (1) from themselves in summer; (2) from themselves after > or = 9 days of light therapy; or (3) from age- and gender-matched healthy controls. Thus, the extent of fall/winter oversleeping recorded by our SAD patients did not differ dramatically from that reported by the general population, but sleep complaints of our SAD patients have been accompanied by features of sleep architecture that are different from healthy controls and are reversed by summer or by bright-light therapy.

Adult↗
PubMed1994

Season, gender, and P300.

Light therapy in patients with seasonal affective disorder has been reported to enhance visual P300 amplitude. This findings raises the possibility that variations in P300 occur naturally in nonpatients as a function of seasonal variation in sunlight. In the present investigation, P300 was studied in a sample of psychiatrically screened normal subjects who were tested at different times of the year. P300 was larger in women than men and varied in relation to season. This pattern is relevant to studies in which subjects are tested under varying sunlight conditions, such as different seasons. In addition, variations in P300 in normal subjects may be relevant to an understanding of the effectiveness of light therapy for patients with seasonal affective disorder.

Adult↗
PubMed1994

Event-related potential abnormalities correlate with structural brain alterations and clinical features in patients with chronic schizophrenia.

Patients with schizophrenia appear to have abnormalities in both brain structures and information processing. Several recent reports have suggested that correlations exist between such measures. We examined the volume of several brain regions using magnetic resonance imaging (MRI), and also assessed both information processing, using brain event-related potentials (ERPs), and clinical symptomatology in sixteen medicated patients with schizophrenia. Subjects were tested using auditory and visual discrimination tasks. From the ERPs elicited by stimuli presented with relative probabilities of 0.1, the N100, N200, and P300 components were identified and measured. All subjects also had MRI scans that included 12 contiguous coronal sections, each 1 cm thick. From these scans, the following structures were identified and the volume or area quantified: third ventricle, lateral ventricles (partial), amygdala and hippocampus (one slice), partial brain volume (in one slice through the parietal lobe), and total prefrontal and temporal lobe gray and white matter in both cortical regions. Significant correlations were found between hippocampal area and the amplitude of the auditory and visual N200, and between the right hippocampus and the visual P300. Lower but significant correlations were seen between auditory P300 and measures of left temporal lobe structures. Auditory P300 amplitude correlated inversely with positive symptoms of schizophrenia. These preliminary results suggest that the ERP abnormalities in patients with schizophrenia are associated with temporal lobe pathology.

Adult↗
PubMed1994

Low-dose indomethacin and prevention of intraventricular hemorrhage: a multicenter randomized trial.

OBJECTIVES: Parenchymal involvement of intraventricular hemorrhage (IVH) is a major risk factor for neurodevelopmental handicap in very low birth weight neonates. Previous trials have suggested that indomethacin would lower the incidence and severity of IVH in very low birth weight neonates. METHODS: We enrolled 431 neonates of 600- to 1250-g birth weight with no evidence for IVH at 6 to 11 hours of age in a prospective, randomized, placebo-controlled trial to test the hypothesis that low-dose indomethacin (0.1 mg/kg intravenously at 6 to 12 postnatal hours and every 24 hours for two more doses) would lower the incidence and severity of IVH. Serial cranial ultrasound examinations and echocardiographs were performed. RESULTS: There were no differences in the birth weight, gestational age, sex, Apgar scores, and percent of neonates treated with surfactant between the indomethacin and placebo groups. Within the first 5 days, 25 (12%) indomethacin-treated and 40 (18%) placebo-treated neonates developed IVH (P = .03, trend test). Only one indomethacin-treated patient experienced grade 4 IVH compared with 10 placebo-treated neonates (P = .01). Sixteen indomethacin-treated neonates and 29 control neonates died (P = .08); there was a difference favoring indomethacin with respect to survival time (P = .06). Eighty-six percent of all neonates had a patent ductus arteriosus on the first postnatal day; indomethacin was associated with significant ductal closure by the fifth day of life (P < .001). There were no differences in adverse events attributed to indomethacin between the two treatment groups. CONCLUSIONS: Low-dose prophylactic indomethacin significantly lowers the incidence and severity of IVH, particularly the severe form (grade 4 IVH). In addition, indomethacin closes the patent ductus arteriosus and is not associated with significant adverse drug events in very low birth weight neonates.

Cerebral Hemorrhage↗
PubMed1994

Using administrative data to screen hospitals for high complication rates.

Medicare's Peer Review Organizations (PROs) now are required to work with hospitals to improve patient outcomes. Which hospitals should be targeted? We used 1988 California discharge data to identify hospitals with higher-than-expected rates of complications in six adult, medical-surgical patient populations. Relative hospital complication rates generally were correlated across clinical areas, although correlations were lower between medical and surgical case types. Higher relative rates of complications were associated with larger size, major teaching facilities, and provision of open heart surgery, as well as with coding more diagnoses per case. Complication rates generally were not related significantly to hospital mortality rates as calculated by the Health Care Financing Administration. Different hospitals may be chosen for quality review depending on the method used to identify poor outcomes.

Aged↗
PubMed1993

Intraventricular hemorrhage and prematurity.

Intraventricular hemorrhage or hemorrhage into the germinal matrix tissues of the developing brain with possible rupture into the ventricular system and parenchyma remains a major problem of preterm neonates and is believed to be attributed to alterations in cerebral blood flow to a damaged germinal matrix capillary bed. Topics discussed in this article include germinal matrix anatomy and physiology, neuropathology, risk of hemorrhage, diagnostic imaging techniques, clinical manifestations, posthemorrhagic hydrocephalus, treatment, and outcomes.

Cerebral Hemorrhage↗
PubMed1992

Risk factors for early intraventricular hemorrhage in low birth weight infants.

Because earlier studies suggested that preterm infants with germinal matrix hemorrhage or intraventricular hemorrhage or both (GMH/IVH) present within the first 12 postnatal hours are at greatest risk for the development of high-grade hemorrhage and neurodevelopmental disability, we examined the risk factors for this insult among 229 neonates of 600 to 1250 gm birth weight in a multicenter study. All had echoencephalography (ECHO) within the first 11 hours and serially for the next 20 days; risk factor data were collected prospectively. Forty-three infants had GMH/IVH within the first 5 to 11 hours (mean age at ECHO 7.7 hours): 18 GMH and 21 grade II, 1 grade III, and 3 grade IV IVH. One hundred eighty-six infants did not have GMH/IVH at a mean age of 7.9 hours. Both groups of infants were similar in birth weight, gestational age, maternal risk factors, cord pH values, and surfactant therapy before ECHO. The group with early IVH had more vertex presentations than the group without early IVH (79% vs 55%, p = 0.043), less maternal tocolytic use (42% vs 60%, p = 0.029), and more vaginal deliveries (67% vs 44%, p = 0.005). In the first 21 days, severe IVH developed in 12 infants with early IVH and in 6 infants without early IVH (p < 0.001). There were more neonatal deaths (16% vs 6%, p = 0.035) and more deaths at any time during the primary hospitalization (23% vs 9%, p = 0.010) among the early IVH group than among the group without early IVH. Multivariate analysis indicated that the mode of delivery, fetal presentation, and birth weight were important and independent prognostic indicators of IVH.

Birth Weight↗