Biomedical subjects

S Arndt

Publications and source records attributed to S Arndt.

At least 55 records · Page 3Linked to original sources

PubMed1999

Cognitive outcome in children and adolescents following severe traumatic brain injury: influence of psychosocial, psychiatric, and injury-related variables.

Previous studies of childhood traumatic brain injury (TBI) have emphasized injury-related variables rather than psychiatric or psychosocial factors as correlates of cognitive outcomes. We addressed this concern by recruiting a consecutive series (N = 24) of children age 5 through 14 years who suffered a severe TBI, a matched group who sustained a mild TBI, and a second matched group who sustained an orthopedic injury. Standardized intellectual, memory, psychiatric, family functioning, family psychiatric history, neurological, and neuroimaging assessments were conducted at an average of 2 years following injury. Severe TBI, when compared to mild TBI and orthopedic injury, was associated with significant decrements in intellectual and memory function. A principal components analysis of independent variables that showed significant (p < .05) bivariate correlations with the outcome measures yielded a neuropsychiatric factor encompassing severity of TBI indices and postinjury psychiatric disorders and a psychosocial disadvantage factor. Both factors were independently and significantly related to intellectual and memory function outcome. Postinjury psychiatric disorders added significantly to severity indices and family functioning and family psychiatric history added significantly to socioeconomic status in explaining several specific cognitive outcomes. These results may help to define subgroups of children who will require more intensive services following their injuries.

Adolescent↗

PubMed1999

Polarity sequence, depression, and chronicity in bipolar I disorder.

Five independent studies show that polarity sequence is associated with prognosis in bipolar I disorder. Episodes in which major depression precedes mania (DMI) lead to higher morbidity than biphasic episodes which begin with mania (MDI). However, little is known about the prognostic significance of polarity sequence for long-term outcome. This study examined polarity sequence across multiple episodes among 165 bipolar I patients followed prospectively for up to 15 years as part of the NIMH Collaborative Study of Depression. Episodes beginning with major depression were significantly longer than those beginning with mania for the first three prospectively observed episodes when pooling all episode types-monophasic, biphasic, and polyphasic. Furthermore, affective polarity at onset for the first prospectively observed episode was associated with polarity at onset for the remaining three episodes. Patients whose first prospectively observed episode began with depression had higher overall morbidity during the entire follow-up period.

Adult↗

PubMed1999

Conjugal loss and syndromal depression in a sample of elders aged 70 years or older.

OBJECTIVE: The goal of this study was to describe the association between conjugal loss and both syndromal depression and depressive symptoms in a prospective cohort study of people aged 70 years or older. METHOD: A measure of syndromal depression, the shortform Composite International Diagnostic Interview (CIDI), and a revised version of the Center for Epidemiologic Studies--Depression Scale (CES-D Scale) were administered to a group of 5,449 elders in a longitudinal cohort study. The authors compared the rates of syndromal depression (CIDI diagnosis) and depressive symptoms (six CES-D Scale symptoms) in married participants and those who lost spouses between the first and second waves of assessment. RESULTS: The rate of syndromal depression in the newly bereaved was nearly nine times as high as the rate for married individuals, and the rate of depressive symptoms was nearly four times as high. The percentage of the bereaved respondents who had scores above threshold on the revised CES-D Scale was higher for those interviewed up to 2 years after loss of a spouse than for married respondents. Age, sex, prior psychiatric history, and the expectedness of the death did not differ between depressed and nondepressed newly bereaved subjects. CONCLUSIONS: Recent bereavement is a significant risk factor for syndromal depression in the elderly. Some widows and widowers experienced high levels of depressive symptoms up to 2 years after the loss of their spouses. Neither demographic variables nor variables concerning the nature of the spouse's death predicted bereavement-related depression.

Age Factors↗

PubMed1999

Impaired glucose tolerance and abnormal movements in patients with schizophrenia.

OBJECTIVE: Diabetes mellitus has been implicated as a risk factor for tardive dyskinesia. The authors examined the association between abnormal movements and impaired glucose metabolism, which often precedes the development of overt diabetes, in patients with schizophrenia. METHOD: Twenty-one patients with DSM-IV schizophrenia receiving neuroleptic medication were given oral glucose tolerance tests involving serial glucose and insulin levels. These values were analyzed in relationship to abnormal involuntary movement ratings. RESULTS: Patients with impaired glucose tolerance had higher mean abnormal movement scores than those without glucose intolerance, but this difference was not statistically significant. There was, however, an association between the magnitude of the fasting insulin level and abnormal movements after the authors controlled for fasting glucose level. Additionally, the fasting glucose level predicted abnormal movements after the authors controlled for age. CONCLUSIONS: Hyperinsulinemia and hyperglycemia associated with insulin resistance may potentially contribute to the pathogenesis of tardive dyskinesia. Findings from this small cross-sectional study suggest a possible relationship that requires clarification through larger, longitudinal studies.

Age Factors↗

PubMed1999

Change in basal ganglia volume over 2 years in patients with schizophrenia: typical versus atypical neuroleptics.

OBJECTIVE: For many years, it has been assumed that medications affect brain chemistry and physiology but not structure. Recent reports suggest that neuroleptic medication changes basal ganglia volume. To explore this possibility, the authors assessed for basal ganglia volume change in individuals who had their basal ganglia structures delineated and measured on magnetic resonance scans at the beginning and end of a 2-year period and who received neuroleptic medication during this time. METHOD: The basal ganglia volumes of 23 male patients with schizophrenia spectrum disorders were measured from manual traces delineating the caudate and lenticular nucleus on magnetic resonance images at admission and 2 years later. Patients' neuroleptic exposure was calculated over the 2 years by using a dose-year formula. RESULTS: During the 2-year period, mean basal ganglia volume of patients receiving predominantly typical neuroleptics increased, while the opposite was observed for patients receiving mostly atypical neuroleptics. Correlation analysis for the entire group showed a positive relationship between the 2-year exposure to typical neuroleptic medication and change in basal ganglia volume and the reverse for exposure to atypical neuroleptics. CONCLUSIONS: In this group, basal ganglia volume increased following exposure to typical neuroleptics and decreased following exposure to atypical neuroleptics.

Adult↗

PubMed1999

Longitudinal study of cognitive function in first-episode and recent-onset schizophrenia.

OBJECTIVE: Whether cognitive function in schizophrenia deteriorates, improves, or remains stable is a crucial question. Few studies have examined the longitudinal stability of cognitive function and the relationship between cognitive performance and clinical symptoms over time in a cohort of well-treated patients with schizophrenia. METHOD: In the present study, 54 patients with first-episode and recent-onset schizophrenia completed a comprehensive cognitive test battery and were rated on symptom measures at index hospitalization and again after 5 years. RESULTS: Performance IQ and full-scale IQ significantly improved, whereas verbal IQ did not change. Group performance improved on some of the neuropsychological tests, including the Circle A letter-cancellation task, free recall of logical memory test score, and the Wisconsin Card Sorting Test. Mean finger-tapping performance worsened over time, whereas performance on other neuropsychological tests did not change. Negative, psychotic, and disorganized symptoms significantly improved over the time period. Changes in negative symptoms were correlated with performance changes in verbal IQ and full-scale IQ but not performance IQ. Improvement in verbal cognition was observed when negative symptoms improved. Psychotic and disorganized symptom dimensions were not correlated with any IQ measure. CONCLUSIONS: These results indicate that in a cohort of young patients receiving neuroleptic treatment early in their illness, cognitive performance does not deteriorate--and may improve. Only one of the three symptom dimensions--negative--was associated with change in cognitive performance. This study supports the view that negative symptoms are associated with a poor long-term cognitive outcome and may be closely related to the primary cognitive deficit in schizophrenia.

Adult↗

PubMed1999

[An online information system "LEITLINIEN-IN-FO"--a contribution to quality management in health care].

An online-information service contianing clinical practice guidelines ("LEITLINIEN-INFO"--available via) based on similar programs from Scotland and Canada--was developed by the German Guidelines Clearinghouse (Agency for Quality in Medicine, Cologne). The service focuses on continuing medical education regarding guideline methodology and tools for critical appraisal of guidelines. It contains guideline appraisal reports developed in cooperation with the German Cochrane-Center. Special importance is given to a hyperlink collection of German and international guideline-data-bases. Backgrounds, aims, and structures of the information program are discussed.

Canada↗

PubMed1999

[The guideline clearing programme of the self-governmental bodies in the German health care system--a project to promote quality assurance in medicine].

Within the German health system guidelines are increasing considered as a meaningful and necessary aid to decision making. In this context the effectiveness of guidelines essentially depends on their methodical quality. Because of the fact that most of the German-language guidelines introduced within the past years show obvious methodological defects, the Agency for Quality in Medicine developed within the last two years the following programme for quality-assurance and promotion of guidelines: 1. Definition of quality policies for clinical practice guidelines in Germany 2. Establishment of quality demands for guidelines 3. Methods and instruments for quality promotion of guideline programmes 4. Measures to promote and check the quality of guidelines ("German Guidelines Clearinghouse") The following article reports on background, aims, instruments, method development and acceptance of the programme.

Delivery of Health Care↗

PubMed1999

The cerebellum plays a role in conscious episodic memory retrieval.

The cerebellum has traditionally been considered to be primarily dedicated to motor functions. Its phylogenetic development and connectivity suggest, however, that it also may play a role in cognitive processes in the human brain. In order to examine a potential cognitive role for the cerebellum in human beings, a positron emission tomography (PET) study was conducted during a "pure thought experiment": subjects intentionally recalled a specific past personal experience (consciously retrieved episodic memory). Since there was no motor or sensory input or output, the design eliminated the possibility that cerebellar changes in blood flow were due to motor activity. During silent recall of a consciously retrieved episodic memory, activations were observed in the right lateral cerebellum, left medial dorsal thalamus, medial and left orbital frontal cortex, anterior cingulate, and a left parietal region. These activations confirm a cognitive role for the cerebellum, which may participate in an interactive cortical-cerebellar network that initiates and monitors the conscious retrieval of episodic memory.

Adult↗

PubMed1998

Relationship between patient variables and plasma clozapine concentrations: a dosing nomogram.

BACKGROUND: Previous work has suggested factors such as gender, smoking behavior, dose, and age affect the amount of drug a patient requires to achieve a desired plasma concentration of clozapine. Plasma clozapine concentrations ranging from 350 to 504 ng/mL in treatment-refractory schizophrenics and schizoaffective patients produce response rates ranging approximately 55-80%. Without the aid of clozapine plasma concentration monitoring, 3-6 months are recommended for a therapeutic clozapine trial. Data suggest that the lag time to response can be reduced by administering a dose that produces a therapeutic clozapine concentration. METHODS: To generate a clozapine dosing nomogram to predict clozapine steady-state plasma concentrations, a cohort of 71 patients was collected via retrospective chart review and/or patient interview. Clozapine steady-state plasma concentrations and demographic variables were obtained. Multiple-linear regression was utilized to examine the relationship between the plasma clozapine concentration and the independent variables. RESULTS: The dosing model that optimally predicted steady-state clozapine plasma concentrations included the variables dose (mg/day), smoking (yes = 0 and no = 1), gender, and a dose-gender interaction variable. The model explained 47% of the variance in the clozapine concentrations (F = 14.42, p < .001, r2 = .47). Two equations, one for male subjects, i.e., clozapine (ng/mL) = 111 (smoke) + 0.464 (dose) + 145, and one for female subjects, i.e., clozapine (ng/mL) = 111 (smoke) + 1.590 (dose)-149, were derived to predict clozapine steady-state plasma concentrations to serve as a clozapine dosing guide for clinicians. CONCLUSIONS: A clozapine dosing nomogram was constructed as a clinical aid to facilitate clozapine dosing.

Adult↗

PubMed1998

Corpus callosum shape and size in male patients with schizophrenia.

BACKGROUND: Corpus callosum (CC) morphology has recently been investigated in schizophrenia using refined imaging and analytic techniques; however, methodological problems and small sample sizes have led to inconsistent findings. METHODS: This study used a large sample of male schizophrenics (n = 79) and male controls (n = 65) to investigate size and shape of the CC on midsagittal magnetic resonance images. Size was determined by tracing the area of the CC, and shape was determined using a landmark-based analysis. In addition, the relationship between CC morphology and phenomenologic variables such as age of onset, length of illness, exposure to medications, and symptom severity was explored. RESULTS: After controlling for age, height, and parental socioeconomic status, there was a main effect of diagnosis on CC size (F = 5.05, df = 1,139, p < .03), with patients' CCs being significantly smaller. No difference was found between patients and controls in CC shape (F = 1.07, df = 18,125, p > .38) or orientation (F = 0.79, df = 18,125, p > .70), using a landmark-based technique. Finally, there was a significant inverse correlation between size of CC and severity of negative symptoms. CONCLUSIONS: These findings support previous studies that have found a decrease in size of the CC in patients with schizophrenia. Moreover, the decrement in volume is generalized, not regional, and is related to the severity of negative symptoms.

Adult↗

PubMed1998

An efficient procedure for permutation tests in imaging research.

Recent interest in hypothesis testing on functional imaging data has spurred the development of several statistical techniques. The purpose of this paper is to provide a method to reduce the computational intensity associated with randomization tests of positron emission tomography imaging data. We discuss the advantages and disadvantages of traditional distributional hypothesis testing versus the advantages and disadvantages of randomization tests. A method for reducing the computational intensity of randomization uses a conjunction of updating and sequenching and results in significantly reduced processing. The running times of randomization methods are compared.

Algorithms↗

PubMed1998

Adaptive functioning following traumatic brain injury and orthopedic injury: a controlled study.

OBJECTIVE: To study adaptive functioning after severe traumatic brain injury (TBI). DESIGN: Case-control study. SETTING: A university hospital and three regional and four community hospitals. SUBJECTS: A consecutive series (n=24) of children age 5 through 14 years who suffered severe TBI were individually matched to subjects who sustained a mild TBI and to a second group who sustained an orthopedic injury with no evidence of TBI. MAIN OUTCOME MEASURES: Standardized adaptive functioning, intellectual, psychiatric, and neuroimaging assessments were conducted on average 2 years after injury. RESULTS: Severe TBI was associated with significantly (p < .05) lower Vineland Adaptive Behavior composite, communication, and socialization standard scores and lower Child Behavior Checklist parent-rated social competence scores compared with children with orthopedic injury. Severe TBI and mild TBI subjects were significantly (p < .05) more impaired than orthopedic subjects on teacher-rated adaptive function. Family functioning, psychiatric disorder in the child, and IQ were significant variables, explaining between 22% and 47% of the variance in adaptive functioning outcomes. CONCLUSIONS: Severe TBI is associated with significant deficits in child adaptive functioning. This association appears to be mediated by family dysfunction, child psychiatric disorder, and intellectual deficits.

Activities of Daily Living↗

PubMed1998

Morphometry in schizophrenia revisited: height and its relationship to pre-morbid function.

BACKGROUND: Morphometry, the measurement of forms, is an ancient practice. In particular, schizophrenic somatology was popular early in this century, but has been essentially absent from the literature for over 30 years. More recently, evidence has grown to support the notion that aberrant neurodevelopment may play a role in the pathophysiology of schizophrenia. Is the body, like the brain, affected by abnormal development in these patients? METHODS: To evaluate global deficit in development and its relationship to pre-morbid function, height was compared in a large group (N = 226) of male schizophrenics and a group of healthy male controls (N = 142) equivalent in parental socio-economic status. Patients in the lower quartile of height were compared to those in the upper quartile of height. RESULTS: The patient group had a mean height of 177.1 cm, which was significantly shorter than the mean height of the control group of 179.4 (P < 0.003). Those in the lower quartile had significantly poorer pre-morbid function as measured by: (1) psychosocial adjustment using the pre-morbid adjustment scales for childhood and adolescence/young adulthood, and (2) cognitive function using measures of school performance such as grades and need for special education. In addition, these measures of pre-morbid function correlated significantly with height when analysed using the entire sample. CONCLUSIONS: These findings provide further support to the idea that abnormal development may play a key role in the pathophysiology of schizophrenia. Furthermore, this is manifested as a global deficit in growth and function resulting in smaller stature, poorer social skills, and deficits in cognitive abilities.

Adolescent↗

PubMed1998

No difference in hippocampus volume detected on magnetic resonance imaging in autistic individuals.

Neuropathological and animal studies have implicated the hippocampus as having a potential role in autism. Current imaging methods are well suited to the detailed measurement of the volume of the hippocampus, which has received little attention in previous imaging studies in autism. We report the results of a magnetic resonance imaging (MRI) study of 35 autistic and 36 control subjects. Detailed (1.5 mm) MRI did not reveal differences in the volume of the hippocampus in autistic individuals.

Adolescent↗

PubMed1998

The Neuropsychiatric Rating Schedule: reliability and validity.

OBJECTIVE: To evaluate reliability and validity for the Neuropsychiatric Rating Schedule (NPRS) interview designed to permit diagnosis of organic personality syndrome (OPS) or personality change due to a general medical condition (PC). METHOD: Subjects from prospective (n = 50) and retrospective (n = 72) studies of traumatic brain injury were aged 6 through 18 years. Parents and children were informants for the NPRS. Convergent and discriminant validity of subtypes of OPS/PC were assessed against standard scales completed by parents and teachers. Interrater reliability data (n = 20), test-retest reliability data (n = 42), as well as sensitivity-to-change data (n = 37) were collected. RESULTS: All subtypes of OPS/PC were diagnosed, but apathy and paranoia subtypes were rare. Rating scale data supported convergent validity of OPS/PC subtypes generated with the NPRS. Affective instability, rage/aggression, and inappropriate social judgment were moderately to highly correlated, but apathy and paranoia could be discriminated from each of these subtypes. Interrater agreement for NPRS items was fair to excellent for all but one item (paranoia). Test-retest reliability was fair to good, and sensitivity to change was demonstrated. CONCLUSION: The NPRS generated reliable and valid diagnoses of the common subtypes of OPS/PC.

Adolescent↗

PubMed1998

Psychiatric disorders in children and adolescents after severe traumatic brain injury: a controlled study.

OBJECTIVE: To study psychiatric and behavioral morbidity associated with severe traumatic brain injury (TBI). METHOD: A consecutive series (n = 24) of children aged 5 through 14 years who suffered a severe TBI were matched to subjects who sustained a mild TBI and to a second matched group who sustained an orthopedic injury with no evidence of TBI. Standardized psychiatric, behavioral, and neuroimaging assessments were conducted on average 2 years after injury. RESULTS: Severe TBI was associated with a significantly higher rate of current "novel" psychiatric disorders (15/24; 63%) compared with children with mild TBI (5/24; 21%) and orthopedic injury (1/24; 4%). Higher effect sizes were evident for child and adolesent self-report of internalizing symptoms rather than externalizing symptoms, for parents' report of overall behavior and internalizing symptoms rather than externalizing symptoms, and for teachers' reports of overall behavior and externalizing symptoms rather than internalizing symptoms. CONCLUSIONS: Severe TBI is a profound risk factor for the development of a psychiatric disorder. Survivors should be assessed for organic personality syndrome, which is the most common psychiatric disorder after this type of injury.

Adolescent↗

PubMed1998

Attention-deficit hyperactivity symptomatology after traumatic brain injury: a prospective study.

OBJECTIVE: To study prospectively the course of attention-deficit hyperactivity (ADH) symptomatology in children and adolescents after traumatic brain injury (TBI). It was hypothesized that ADH symptomatology would be significantly related to severity of injury. METHOD: Subjects were children (n = 50) aged 6 to 14 years at the time they were hospitalized after TBI. The study used a prospective follow-up design. Assessments of preinjury psychiatric, behavioral, socioeconomic, family functioning, and family psychiatric history status were conducted. Severity of injury was assessed by standard clinical scales, and neuroimaging was analyzed. RESULTS: The main finding of this study was that change in ADH symptomatology in the first 2 years after TBI in children and adolescents was significantly related to severity of injury. Overall ADH symptomatology during the study was significantly related to a measure of family dysfunction when family psychiatric history, socioeconomic status, and severity of injury were controlled. CONCLUSION: The presence of a positive "dose-response" relationship between severity of injury and change in ADH symptoms, present from the 3-month assessment, was consistent with an effect directly related to brain damage.

Adolescent↗