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Biomedical subjects

Stephan Arndt

Publications and source records attributed to Stephan Arndt.

At least 19 recordsLinked to original sources
PubMed2006

Neuropsychological performance is associated with vascular function in patients with atherosclerotic vascular disease.

OBJECTIVE: We previously reported preliminary data (N=14) demonstrating a significant and positive relationship between forearm vascular function and neuropsychological performance in individuals with atherosclerotic vascular disease (AVD). The current study was conducted to confirm and extend those findings in a much larger, nonoverlapping sample. METHODS AND RESULTS: Participants were 82 individuals with AVD, with no history of stroke, cardiac surgery, or dementia. Forearm vascular function was measured before and after brachial artery infusion of vasoactive agents (acetylcholine, nitroprusside, verapamil). Neuropsychological functioning was assessed with the Repeatable Battery for the Assessment of Neuropsychological Status. Statistical analysis included multiple regression and partial correlations, controlling for education. Vascular function was significantly and positively associated with neuropsychological performance [R2 change = 0.116, F change (3,74) = 3.72, P = 0.015]. Follow-up analyses indicated that smooth muscle function was the aspect of vascular function most strongly associated with neuropsychological performance. Individual vascular risk factors were not significantly associated with neuropsychological performance when controlling for vascular function. CONCLUSIONS: Better vascular function is significantly associated with better neuropsychological performance in individuals with AVD. It is possible that this relationship exists in healthy elderly individuals as well, although this cannot be determined based on the existing data, because a healthy comparison group was not studied. With additional research, measures of vascular function might be useful in the early identification of individuals who are at greatest risk for developing vascular cognitive impairment.

Aged↗
PubMed2006

Co-morbid health conditions at mid-life in the Iowa adoptees.

Adverse health effects due to alcohol and illicit drug abuse and dependence have been well documented. This study examines the effect of substance misuse on five major groups of health conditions using a sample of well characterized adoptees. The sample consisted of 742 adoptees interviewed in the last wave of the Iowa Adoption Studies. Death rate analyses included an additional 34 participants who had died prior to the last follow-up. Substance use patterns and medical history were assessed using the SSAGA-II (Bucholz, K. K., Cadoret, R. J., Cloninger, C. R., Dinwiddie, S. H., Hesselbrock, V. M., Nurnberger, J. L., Jr., et al. (1994). A new, semi-structured psychiatric interview for use in genetic linkage studies: a report on the reliability of the SSAGA. Journal of Studies on Alcohol, 55 (2), 149-158). Subjects were divided into three groups according to DSM-IV diagnostic criteria, controls, alcohol abuse or dependence only (alcohol only), and the Alcohol-Drug group (abuse or dependence diagnosis on at least one illicit substance with or without alcohol diagnosis). Incidence rates of various diseases were measured using logistic regression. Survival analyses were used to examine whether substance abusers developed cardiovascular or metabolic disease at an earlier age than control subjects. Diagnostic grouping made no difference in the incidence rates or age of onset of health conditions. The amount of alcohol consumed by males significantly predicted higher number of overall health complaints as well as higher incidence rates of cardiovascular disease. The amount of illicit drug exposure did not predict an earlier age of diagnosis for cardiovascular or metabolic disease. Individuals in the Alcohol-Drug group had an increased incidence of deaths than either the alconly or the control groups.

Adoption↗
PubMed2006

Probabilistic index: an intuitive non-parametric approach to measuring the size of treatment effects.

Effect sizes (ES) tell the magnitude of the difference between treatments and, ideally, should tell clinicians how likely their patients will benefit from the treatment. Currently used ES are expressed in statistical rather than in clinically useful terms and may not give clinicians the appropriate information. We restrict our discussion to studies with two groups: one with n patients receiving a new treatment and the other with m patients receiving the usual or no treatment. The standardized mean difference (e.g. Cohen's d) is a well-known index for continuous outcomes. There is some intuitive value to d, but measuring improvement in standard deviations (SD) is a statistical concept that may not help a clinician. How much improvement is a half SD? A more intuitive and simple-to-calculate ES is the probability that the response of a patient given the new treatment (X) is better than the one for a randomly chosen patient given the old or no treatment (Y) (i.e. P(X > Y), larger values meaning better outcomes). This probability has an immediate identity with the area under the curve (AUC) measure in procedures for receiver operator characteristic (ROC) curve comparing responses to two treatments. It also can be easily calculated from the Mann-Whitney U, Wilcoxon, or Kendall tau statistics. We describe the characteristics of an ideal ES. We propose P(X > Y) as an alternative index, summarize its correspondence with well-known non-parametric statistics, compare it to the standardized mean difference index, and illustrate with clinical data.

Clinical Trials as Topic↗
PubMed2006

Perception of socially relevant stimuli in schizophrenia.

To examine whether patients with schizophrenia have deficits in the appraisal of socially relevant stimuli, we tested 20 patients and 14 healthy volunteers equated for parental socioeconomic status on recognition of gender stimuli, emotional people stimuli, and emotional scenes. Patients with schizophrenia showed deficits in discrimination of subtle gender differences and in the identification of emotion from human shapes and body motion. Patients showed no impairment on measures of hedonic appraisal of emotional scenes and recognition of emotional expression in human face stimuli. Across tasks, subjects with schizophrenia showed poorer identification of happiness, anger, and fear. The findings point towards circumscribed domains of impaired social cognition in schizophrenia and suggest specific further hypotheses about the neural dysfunction that may underlie them.

Adult↗
PubMed2006

Aggressive behavior in patients with stroke: association with psychopathology and results of antidepressant treatment on aggression.

OBJECTIVE: To examine, in a post hoc analysis of an antidepressant treatment trial, correlates of irritability and aggression after stroke and changes in irritability scores associated with antidepressant treatment. DESIGN: Aggressive patients (n=23) were compared with nonaggressive patients (n=69) on numerous measures of psychopathology, poststroke impairment, and neuroimaging findings. SETTING: All patients were hospitalized at the time of the initial evaluation for acute stroke or for rehabilitation therapy. PARTICIPANTS: Ninety-two patients from the Iowa City Stroke Study were classified as aggressive or nonaggressive, based on symptoms elicited by the Present State Examination (PSE) and from family or caretaker reports. INTERVENTION: All patients were randomized to receive nortriptyline, fluoxetine, or placebo using a double-blind methodology. MAIN OUTCOME MEASURE: The change in aggression score as elicited by the PSE at the beginning and the end of a 12-week treatment trial. RESULTS: Twenty-five percent (23/92) of patients reported irritability or aggression. Irritable and aggressive patients had higher total PSE scores, Hamilton Depression Rating Scale scores, Hamilton Anxiety Rating Scale (HAMA) scores, and lower Mini-Mental State Examination scores. They also had lesions that were more proximal to the frontal pole. Stepwise regression analysis showed that HAMA scores and proximity of lesion to the frontal pole were significant independent predictors of irritability. Among irritable and aggressive patients with depression who responded to antidepressants, there was a significantly greater reduction in irritability after treatment, compared with patients whose depression did not lessen with treatment. CONCLUSIONS: Several factors, such as severity of impairment, other psychopathology, and neurobiologic factors, appear to contribute to irritable and aggressive behavior in stroke patients. If depression accompanies aggression, the results of this small study suggest that successful treatment of depression may reduce aggressive behavior.

Aged↗
PubMed2006

Characteristics of admissions for primary stimulant dependence during 2001.

The production and consumption of synthetic stimulants has been increasing in recent years accompanied by an increase in the number of individuals seeking treatment for synthetic stimulant "abuse."1 The misuse of stimulants is occurring at younger ages and primarily in the context of polysubstance use. This article examines the characteristics of admissions entering treatment centers that received some form of public funding in 2001 as compiled in the Treatment Episodes Data Set produced by the Substance Abuse Mental Health Services Administration, Office of Applied Studies. It compares those admissions indicating stimulants as a primary substance of use with those admissions not listing stimulants. Findings indicated that stimulant primary admissions were younger, more frequently Caucasian, and more frequently female than nonstimulant admissions. Additionally, stimulant primary admissions had fewer prior treatment episodes and substance use referrals than the nonstimulant admissions but were more commonly referred by the criminal justice system, raising the concern that adequate screening for stimulant misuse is not occurring in health care settings.

Adult↗
PubMed2006

Concurrent tracking of alcohol use and bipolar disorder symptoms.

OBJECTIVES: Alcohol use disorders (AUDs) are common co-occurring conditions in patients with bipolar disorder (BD), but it is unclear whether or not AUD and BD symptoms are temporally correlated. The primary aim of this analysis was to examine concurrent symptom tracking and how the relative onsets of AUD and BD influence the concurrent tracking of symptoms. METHODS: Participants met DSM-IV criteria for bipolar I disorder, manic or mixed, with no prior hospitalizations and minimal treatment. Patients were rated for alcohol use and bipolar symptom severity on a weekly basis for up to 7 years. For analysis purposes, patients were placed into groups with no AUD (BD Only; n = 21), onset of AUD either concurrent with or after the onset of bipolar symptoms (BD First; n = 32), and onset of AUD at least 1 year before the onset of bipolar symptoms (AUD First; n = 18). RESULTS: None of the patient groups demonstrate consistent positive or negative temporal correlations between alcohol use and affective symptoms. However, there were significant between-group differences on the relationship of symptom tracking and age of BD onset. For the AUD First group, the correlation between age of BD onset and symptom tracking was positive 0.41. However, for the BD First and BD Only groups the correlations were negative (-0.32 and -0.41, respectively). Moreover, for patients whose BD onset was < or =18 years old, the correlation between age of onset and tracking was -0.47. CONCLUSIONS: These findings suggest that although there is no direct temporal correlation of AUD and BD symptoms in subgroups of BD patients, age at illness onset contributes to the complex relationship between BD and AUD. For younger patients there may be a greater likelihood that alcohol use and bipolar symptoms increase or decrease in unison.

Adolescent↗
PubMed2005

Using a brief intervention to improve decisional capacity in schizophrenia research.

Studies have shown that individuals with psychiatric or general medical illness can benefit from interventions designed to enhance decisional capacity for research informed consent. In some cases, interventions have been rather lengthy or complex. The current study was designed to determine whether a brief intervention could improve decisional capacity in people with schizophrenia. Thirty individuals with schizophrenia and 30 healthy comparison participants were presented with a hypothetical research scenario. Decisional capacity was assessed with the MacArthur Competence Assessment Tool-Clinical Research version. Those with schizophrenia received a brief intervention aimed at improving understanding of the research protocol, after which decisional capacity was reassessed. A neuropsychological battery and symptom rating scales were also administered. At baseline, the schizophrenia group earned significantly lower scores than the comparison group on 2 aspects of decisional capacity (understanding, appreciation). At follow-up, the schizophrenia group had improved significantly on understanding and was no longer significantly different from the comparison group on any of the 4 dimensions of decisional capacity. Follow-up analyses also showed a significant effect of the intervention on a subset of the schizophrenia group who had performed most poorly at baseline. Participants with schizophrenia earned significantly lower scores than those in the comparison group across multiple neuropsychological domains. These findings add to the existing literature indicating that brief interventions can improve decisional capacity in individuals with schizophrenia, despite the fact that the illness typically causes significant cognitive dysfunction. The use of such interventions will enable a larger number of people with schizophrenia to make informed decisions regarding research participation.

Adult↗
PubMed2005

Clozapine-induced weight gain associated with the 5HT2C receptor -759C/T polymorphism.

Weight gain has been documented as a significant adverse effect associated with many of the atypical antipsychotic medications. Several recent reports have linked a -759C/T polymorphism of the 5HT2C receptor gene and obesity as well as chlorpromazine, risperidone, and clozapine induced to weight gain. This aim was to determine the association between changes in body mass index (BMI) during clozapine treatment and the -759C/T polymorphism of the 5HT2C receptor gene. This study included 41 patients with treatment-refractory schizophrenia (DSM-IV) who were followed prospectively during treatment with clozapine. Weight and height measurements were obtained prior to starting clozapine and after 6-months of treatment. Genomic DNA was isolated from a whole blood sample and analyzed for the -759C/T polymorphism of the 5HT2C receptor gene. A chi(2) analysis comparing whether or not the subjects carried a -759T allele in subjects grouped as having an increase of more or less than 7% of their baseline BMI during treatment with clozapine found that the presence of the -759T allele was significantly higher in subjects with less than or equal to a 7% increase in baseline BMI compared to those with a greater than 7% increase in BMI. A multiple linear regression analysis showed that both baseline BMI and the presence or absence of the -759T allele had significant effects on 6-month BMI. The T allele may have a protective function in preventing significant weight gain from clozapine. Subjects without the -759T variant allele were at a greater risk for weight gain from clozapine over 6-months compared to those with the -759T allele.

Adult↗
PubMed2005

More powerful two-sample tests for differences in repeated measures of adverse effects in psychiatric trials when only some patients may be at risk.

Common adverse effect measures in psychiatric trials are typically analysed with repeated measures ANOVA, despite having distributions which violate key assumptions of that method; moreover, some adverse effects may be concentrated in vulnerable subgroups of participants. For testing treatment differences in adverse effects, we propose use of Kendall's taub as a summary measure of within-participant trends in adverse events, in conjunction with a weighted modification of a rank test proposed by Conover and Salsburg. Data on extrapyramidal side effects from a controlled clinical trial conducted in persons with treatment resistant schizophrenia was used to compare the proposed analysis to repeated measures ANOVA using mixed models and alternate tests for treatment differences in taub trend scores.

Antipsychotic Agents↗
PubMed2005

Alcohol misuse and mood disorders following traumatic brain injury.

CONTEXT: Alcohol abuse and/or dependence (AA/D) and mood disturbance are co-occurring conditions among patients who have had a traumatic brain injury (TBI). However, the relationship between these disorders has not been extensively studied. OBJECTIVE: To examine the relationship of AA/D and post-TBI mood disorders and the effect of these conditions on psychosocial outcome. DESIGN: Prospective, case-control surveillance study conducted during the first year following trauma. Settings University hospital level I trauma centers and specialized rehabilitation units. Patients One hundred fifty-eight TBI patients with closed head injury with and without a history of AA/D. METHODS: We prospectively compared psychiatric, neuropsychological, and psychosocial outcomes among the patients, who were evaluated at baseline and at 3, 6, and 12 months after trauma. Psychiatric diagnosis was made using a structured clinical interview and DSM-IV criteria. Neuropsychological testing results and quantitative magnetic resonance images were obtained at the 3-month follow-up. RESULTS: A history of AA/D was significantly more frequent among patients who developed mood disorders during the first year following TBI. There was also a significantly higher frequency of mood disorders among patients with alcohol abuse relapse. Patients with a history of AA/D had significantly reduced frontal gray matter volumes than did patients without a history of alcohol abuse. In addition, patients who resumed alcohol abuse had decreased medial frontal gray matter volumes and impaired performance in executive tasks. Both AA/D and mood disorders following TBI were associated with a poor vocational outcome. CONCLUSIONS: Previous alcohol abuse increases the risk of developing mood disorders after TBI, and emotional disturbance, in turn, increases the risk of alcohol abuse relapse. Alcohol's neurotoxic effects and TBI likely interact to produce greater disruption of the neural circuits that modulate reward, mood, and executive function. Patients with a history of AA/D who also developed mood disorders following TBI had major difficulties resuming a productive life.

Adult↗
PubMed2005

Assessing intimate partner violence in incarcerated women.

The purpose of this study to assess the psychometric qualities of a screening instrument for intimate partner violence, the Index of Spouse Abuse (ISA), for use with incarcerated women. Principal components factor analysis was conducted on data collected from 149 incarcerated women. The ISA demonstrated excellent internal consistency with this population and appears to be a psychometrically sound instrument that can be given in a short period of time.

Adult↗
PubMed2005

Older admissions to substance abuse treatment in 2001.

OBJECTIVE: The number of older people with substance abuse problems is expected to increase over the next decade. Given the expected growth in the number of elderly clients needing substance abuse treatment, the authors provide a description of admissions of patients age 55 years and over to facilities receiving some public funds. METHODS: The Treatment Episode Data Set (TEDS), a public-use data-set, contained information on 58,073 admissions to substance treatment (age 55+) and 1,043,910 admissions age 30-54 years. RESULTS: Older admissions listed only one substance-daily use of alcohol. Admission record notations indicated that these admissions were more frequently associated with income, insurance, and marriage or divorce than younger admissions. As in younger admissions, criminal justice was a major source of referral to treatment. Older patients' admissions records indicated fewer previous treatment experiences. Older male and female admissions were similar in many regards, but differed in their treatment history. The current treatment admission was more often the first for female admissions. Older female admissions were likely to be more educated than their male counterparts, with a later age at onset. CONCLUSIONS: Older admissions to substance abuse treatment differed in important ways from younger adult admissions. The older admissions tended to come from a more stable environment (income, insurance, marriage). Despite their very high frequency and amount of drinking, few of these admissions were referred to treatment by healthcare workers.

Accidents, Traffic↗
PubMed2005

Predictive values of neurocognition and negative symptoms on functional outcome in schizophrenia: a longitudinal first-episode study with 7-year follow-up.

OBJECTIVE: The relationship between cognition and outcome in people with schizophrenia has been established in studies that, for the most part, examined chronic patients and were cross-sectional in design. The purpose of this study was to analyze the relationships between neurocognitive variables assessed at illness onset and functional outcome in a longitudinal design. An additional area of interest was whether the severity of negative symptoms would predict outcome independently from neurocognitive variables or whether there would be an overlap in their predictive power. METHOD: The authors administered a comprehensive cognitive battery and clinical assessments to 99 subjects who were in their first episode of illness and analyzed the relationship of cognition and symptom severity at intake with community outcome after an average follow-up period of 7 years. RESULTS: Verbal memory, processing speed and attention, and the severity of negative symptoms at intake were related to subsequent outcome. Global psychosocial functioning was predicted by negative symptoms and attention. Verbal memory was the significant predictor of the degree of impairment in recreational activities. Impairment in relationships was predicted by negative symptoms and memory, whereas attention and negative symptoms were predictive of work performance. There was an overlap in the variance in outcome explained by cognitive variables and negative symptoms. CONCLUSIONS: Verbal memory and processing speed and attention are potential targets for psychosocial interventions to improve outcome. Results from cross-sectional or chronic patient studies do not necessarily correspond to the findings of this prospective first-episode study in which cognition appears to explain less of the variance in outcome.

Adaptation, Psychological↗
PubMed2005

Informed consent in medication-free schizophrenia research.

OBJECTIVE: The authors' goal was to determine whether people with schizophrenia experience changes in decisional capacity when their antipsychotic regimens are discontinued for research purposes. METHOD: Capacity for informed consent for research, neuropsychological performance, and psychiatric symptoms were assessed before and after discontinuation of antipsychotic medication in 10 individuals with schizophrenia. RESULTS: Overall, participants showed minimal change on most measures during the medication-free interval, although their reasoning ability declined significantly. All participants who demonstrated adequate understanding of study procedures at enrollment retained this capacity throughout the study. CONCLUSIONS: Participants in medication-free schizophrenia research do not show a major decline in decisional capacity. However, the apparent decline in reasoning ability found in this study is of concern and underscores the need for both additional research on this topic and the development of remediational interventions aimed at enhancing this aspect of decisional capacity.

Adult↗
PubMed2004

Validity of symptom assessment in psychotic disorders: information variance across different sources of history.

BACKGROUND: Factors such as poor insight, amotivation, suspiciousness, disorganized speech and attentional problems may interfere with the ability of acutely ill individuals with psychotic disorders to provide a valid account of their symptoms. This study was designed to determine the degree to which history provided by such subjects is consistent with that obtained from other sources. METHOD: Fifty-five subjects presenting with psychotic disorders were multiply evaluated with a semi structured interview, the Comprehensive Assessment of Symptoms and History (CASH), which includes the Scales for the Assessment of Negative and Positive symptoms (SANS and SAPS). One interviewer assessed the severity of the patient's symptoms in the previous month based solely on information provided by the patient. A second rater made symptom ratings based on information obtained from a "best informant". Following this, a consensus rating was established based on an extensive evaluation and review of all sources of information. An item-by-item comparison of the three sets of symptom ratings was then quantified by paired t-tests, simple and multiple correlations. RESULTS: Positive and negative symptoms ratings based on the subjects' report were significantly lower than the corresponding consensus ratings. However, those based on the informants' report did not differ from consensus ratings for negative symptoms. Information obtained from subjects and from informants together accounted for a majority of the variance of the consensus ratings. CONCLUSIONS: These findings demonstrate that assessment limited to patients' own reports are likely to underestimate psychopathology in acutely ill patients with psychotic disorders. Obtaining corroborative history from a family member may substantially improve the validity of the assessment of negative symptoms.

Adult↗
PubMed2004

Repetitive transcranial magnetic stimulation as treatment of poststroke depression: a preliminary study.

BACKGROUND: Depression has a significant impact on poststroke recovery and mortality. There are a proportion of patients with poststroke depression (PSD) who do not respond to antidepressants. Repetitive Transcranial Magnetic Stimulation (rTMS) might be a safe and effective alternative in these refractory cases. METHODS: We conducted a randomized, parallel, double-blind study of active versus sham left prefrontal rTMS in patients with refractory PSD. After discontinuing antidepressants, patients were randomly assigned to receive 10 sessions of active (10 Hz, 110% of the motor threshold, 20 trains of 5 seconds duration) or sham left prefrontal rTMS. Efficacy measures included HAM-D scores, response and remission rates. Patients completed a neuropsychological battery at baseline and after completing the protocol. RESULTS: When compared with sham stimulation, 10 sessions of active rTMS of the left dorsolateral prefrontal cortex were associated with a significant reduction of depressive symptoms. This reduction was not influenced by patient's age, type or location of stroke, volume of left frontal leukoaraiosis or by the distance of the stimulating coil to the prefrontal cortex. However, there was a significant positive correlation between the percentage of reduction of Ham-D scores and frontal gray and white matter volumes. There were no significant changes in cognitive functioning between the active and the sham stimulation groups. In addition, there were few and mild adverse effects that were equally distributed among groups. CONCLUSIONS: Taken together, these preliminary findings suggest that rTMS may be an effective and safe treatment alternative for patients with refractory depression and stroke.

Aged↗