Large-scale ensemble averaging of ambulatory impedance cardiograms

Impedance cardiography has been used increasingly to measure human physiological responses to emotional and mentally engaging stimuli. The validity of large-scale ensemble averaging of ambulatory impedance cardiograms was evaluated for preejection period (PEP), interbeat interval, and dZ/dt_(min) amplitude. We tested whether the average of “classical” 60-sec ensemble averages across periods with fixed activity, posture, physical load, social situation, and location could be accurately estimated from a single large-scale ensemble average spanning these entire periods. Impedance and electrocardiograms were recorded for about 24-h from 21 subjects. Recordings were scored by seven raters, using both methods for each subject. Good agreement (average intraclass correlation coefficient was .91) between both ensemble averaging methods was found for all three cardiac function measures. The results indicate that for unambiguous ambulatory impedance cardiograms, large-scale ensemble averaging is valid, which makes measuring prolonged changes in cardiac sympathetic activity by measuring ambulatory PEP feasible even in large epidemiological samples.     

Estimating the mean effect size in meta-analysis: Bias,precision, and mean squared error of different weighting methods

Although use of the standardized mean difference in meta-analysis is appealing for several reasons, there are some drawbacks. In this article, we focus on the following problem: that a precision-weighted mean of the observed effect sizes results in a biased estimate of the mean standardized mean difference. This bias is due to the fact that the weight given to an observed effect size depends on this observed effect size. In order to eliminate the bias, Hedges and Olkin (1985) proposed using the mean effect size estimate to calculate the weights. In the article, we propose a third alternative for calculating the weights: using empirical Bayes estimates of the effect sizes. In a simulation study, these three approaches are compared. The mean squared error (MSE) is used as the criterion by which to evaluate the resulting estimates of the mean effect size. For a meta-analytic dataset with a small number of studies, theMSE is usually smallest when the ordinary procedure is used, whereas for a moderate or large number of studies, the procedures yielding the best results are the empirical Bayes procedure and the procedure of Hedges and Olkin, respectively.     

Pavlovian eyeblink conditioning in combat veterans with and without post-traumatic stress disorder

Several recent studies have investigated relationships between post-traumatic stress disorder (PTSD) and learning and memory problems. These reports have found in general that not only does PTSD affect trauma-related memories, but when patients with PTSD are compared with similar trauma patients without PTSD, general memory impairments have been found. The present paper reports a study in which associative learning, using Pavlovian eyeblink conditioning, was investigated in combat veterans with and without chronic PTSD, using interstimulus intervals of 500 and 1000 msec in two separate experiments. Although several recent reports suggest that larger-magnitude autonomic conditioned responses occur in patients with PTSD during Pavlovian conditoning, the present study found evidence of impaired Pavlovian eyeblink conditioning in combat veterans with and without PTSD, compared to non-combat veterans. Although these data suggest that combat leads to an impaired associative learning process regardless of whether PTSD is apparent, a group of community-dwelling combat veterans not under medical treatment showed normal conditioning, suggesting that variables other than prior combat must also be involved.     

Body image and self-esteem in adolescent ballet dancers.

Body-image disturbances and low self-esteem have been implicated in the pathogenesis of eating disorders. This study investigated self-perception of body and personality among adolescent ballet dancers in a cross-sectional survey. Two questionnaires assessing "my body right now" and "my personality right now," using semantic differentials were completed by 90 ballet school students and 156 controls. Adolescent female dancers (ages 13 to 17 years) scored higher than age-matched controls and 11- to 12-yr. old peers on Undesirability and Sensitivity for personality and Unattractiveness for body. For both subscales of personality, differences were also found between male and female dancers; female ballet students scored higher. Within the control group a difference could be found only for Sensitivity on which girls scored higher than boys. Male dancers did not differ from controls except for a lower score on the Body mass measure. Adolescent female dancers showed a distinct answering profile for 7 of 16 semantic differentials in each questionnaire implicating less favorable body image and self-esteem. Interventions focused particularly on enhancing self-esteem may be useful in the prevention of psychopathology in adolescent ballet dancers.     

Influences of Marital Conflict on Child Adjustment: Review of Theory and Research

This review summarizes the literature on the relationship between marital conflict and child maladjustment with an emphasis on variables that qualify, explain the association, or both. Following a historical review, the modest findings on the strength of the association between marital conflict and child maladjustment is explored. The definition of marital conflict is clarified through specification of its various dimensions (frequency, intensity, content, resolution). The role of variables that serve to moderate and/or mediate the relationship between marital conflict and child maladjustment are elaborated. Mediating models include exposure theories (Modeling, Cognitive–Contextual effects: appraisal of threat and blame, and Emotional Insecurity) and changes in the parent–child relationship (Spillover). Variables that moderate or qualify the relationship include children's cognitions and behaviors, contextual factors, and demographic differences. A model is presented summarizing these mechanisms. Research recommendations are proposed and the clinical implications of this literature are addressed.     

Association of heart rate and heart-rate variability with scores on the emotion profile index in patients with acute coronary heart disease.

We investigated the link between the eight basic emotions named by Plutchik and heart rate, heart-rate variability in the 114 patients, 86 men and 28 women (M = 53.8 yr., SD = 8.0) with acute coronary heart disease during the initial 24-hr. stay in the coronary care unit and again at hospital discharge. Variability in heart rate was significantly positively associated with scores on Trust (the emotional state acceptance) at hospital admission and discharge in the patients with unstable angina and non-Q-wave infarction, on Aggression in the patients with unstable angina at hospital discharge and at hospital admission in the patients with non-Q-wave infarction. There was inverse relation on Timid (the emotional state fear) and Gregarious (joy) at hospital admission and on Distrust (disgust or rejection), Depressed (sadness), and Dyscontrol (impulsiveness) at hospital discharge in the patient with non-Q-wave infarction. There was no significant association between heart-rate variability and the scores on the Emotion Profile Index in the patients with anterior and posterior myocardial infarction. There was no statistically significant association between heart rate and scores on the Emotion Profile Index in the patients with acute coronary disease at hospital admission and discharge. Our results suggest psychological interventions that enhance emotional states represented by the Trust and Aggression scales and minimize those represented by Depressed, Dyscontrol, Timid, and Distrust scales could have a beneficial effect on cardiovascular function in the patients with unstable angina and non-Q-wave infarction in a hospital setting.     

The existence of comprehension patterns in Broca's aphasia.

Berndt and Caramazza (1999) claim that Grodzinsky, Pi?ango, Zurif, and Drai (1999) were able to show a canonical-noncanonical difference (e.g., actives vs. passives) in the comprehension of Broca's aphasic patients only because of a patient selection bias. We show that the canonical-noncanonical comprehension pattern exists apart from any such bias, and that this pattern bears importantly on our understanding of the neuroanatomical organization of comprehension capacity at the sentence level.     

The medico-legal status of young sex offenders: forensic psychiatric evaluations in Sweden 1988-1995.

Young sex offenders (YSOs) attract significant public and professional concern. YSOs might be perceived as more psychologically deviant or dangerous than other offenders. This study focused on how often YSOs subjected to forensic psychiatric investigation (FPI) were declared medico-legally insane as compared to young non-sex offenders and adult sex offenders. Logistic regression models were applied to data from all major FPIs performed in Sweden between 1988 and 1995 (N=4354) to explore factors affecting the likelihood of receiving a medico-legal insanity declaration. When we adjusted for the statistical effects of age, sex offender status, and psychopathology, YSOs (n=47) were three to four times more likely to be declared insane in the medico-legal sense. The results indicate that YSOs in Sweden constitute a medico-legally distinct subgroup of forensic psychiatric examinees.