Biomedical subjects

L H Epstein

Publications and source records attributed to L H Epstein.

At least 55 records · Page 3Linked to original sources

PubMed1997

Habituation of facial muscle responses to repeated food stimuli.

We have shown in a series of studies that the human salivary response habituates to repeated presentation of gustatory cues. Parallel animal research has shown that mouthing and food acceptance also habituate. Facial expressions represent a complex response pattern in animals and humans that may provide an objective measurement of motivation to eat. The current study assessed whether facial muscles (orbicularis oris region, risorius region, and zygomaticus region) that regulate mouthing habituate to repeated presentations of a small amount (3 kcal) of a pleasant tasting food stimulus. Participants were randomly assigned to groups that received ten presentations of the same or changing taste stimuli. Following these trials all subjects were presented a novel dishabituating stimulus followed by the habituating stimulus. Integrated facial electromyography EMG responses over each region were measured for a 50 second period following the taste stimulus. Results showed differential habituation rates across the two groups, with participants in the repeated taste group showing decreases in contrast to the changing taste group who did not decrease. The participants in the repeated taste group showed dishabituation of these responses. These results systematically replicate basic animal research, and extend the number of responses related to eating in humans that habituate to repeated food presentations.

Adolescent↗

PubMed1997

The effect of dietary fat on salivary habituation and satiation.

This study was designed to explore the effect of dietary fat and carbohydrate on oral habituation. Forty women (18-21 years old) were randomized to 1 of 4 yogurt conditions that varied levels of dietary fat and carbohydrate. Subjects consumed 0.4 g of yogurt per pound per trial until they indicated fullness in up to 15 trials, with salivation, number of trials to fullness, and ratings of hedonics, appetite, and fullness measured. Subjects in the high-fat conditions demonstrated a significantly faster rate of salivary habituation than subjects in the low-fat conditions, and consumed less volume of yogurt but consumed more calories. The rate of habituation was not influenced by carbohydrate content of the yogurt. These findings suggest that oral habituation in humans is sensitive to macronutrient content of food.

Adolescent↗

PubMed1997

Effects of decreasing sedentary behaviors on activity choice in obese children.

In this study, methods of decreasing highly preferred sedentary behaviors were compared and the consequent effects on activity choice were examined. Following free choice of sedentary and physical activities, 34 obese children either were positively reinforced for decreases in high-preference sedentary activity, were punished for high-preference sedentary activity, had access to high-preference sedentary activity restricted, or had no contingencies on activity (control group). Children randomized to reinforcement and punishment were more physically active on intervention days than the control group. Liking for targeted sedentary activity decreased in the reinforcement group, but increased in the restriction and control groups. Results suggest that reinforcing decreases in high-preference sedentary activity can increase physical activity and decrease liking for targeted sedentary activities.

Analysis of Variance↗

PubMed1997

Relationships between TriTrac-R3D vectors, heart rate, and self-report in obese children.

The TriTrac (Professional Products, Inc., Madison, WI) triaxial accelerometer and diary self report were compared with adjusted heart rates to evaluate 3 d of leisure-time activity in 35 8- to 12-yr-old obese children. Adjusted heart rates were calculated by subtracting preexercise resting heart rates from heart rates measured in the field. TriTrac and self-reported data were converted to multiples of resting metabolic rate (METs). Correlations between accelerometer METs and adjusted heart rates (r = 0.71) were significantly higher (P < 0.001) than correlations between adjusted heart rates and self-reported METs (r = 0.36) or accelerometer and self-reported METs (r = 0.38). Self-reported METs had higher mean standard errors in estimating heart rates (13.93 +/- 6.15 beats.min-1) than did accelerometer METs (10.94 +/- 5.62 beats.min-1; P < 0.001), were significantly greater than accelerometer METs (2.50 +/- 1.48 vs 1.80 +/- 1.48; P < 0.05) and systematically overestimated accelerometer METs. The anteroposterior vector accounted for 36%, and the vector magnitude score accounted for 34% of the variance in unadjusted heart rates. The mediolateral vector and vector magnitude score accounted for 69% of the variance in self-reported METs. The vertical vector did not account for variance in either unadjusted heart rates or self-reported METs. It was concluded that the TriTrac yielded a better estimate of activity in obese children than self report. In addition, the vector magnitude composite score of the TriTrac accounted for significantly more variance in both self-reported activity and unadjusted heart rates as compared with the vertical directional vector of the TriTrac.

Child↗

PubMed1997

Allocation of attentional resources during habituation to food cues.

Two experiments were designed to test the hypothesis that habituation to repeated food cues can be inhibited by allocating processing resources to nonfood cues. In two experiments, the salivary response to 10 presentations of lemon yogurt was assessed while subjects engaged in a controlled cognitive search task (demanding attentional resources), an automatic search task (needing fewer attentional resources), or no task. In Experiment 1, the controlled and automatic search tasks differed in the number of memory set items. In Experiment 2, the size of the memory sets was held constant, and individuals were provided practice to stabilize the different search strategies in the task. The automatic search and no task groups habituated to the repeated presentation of food cues in both experiments, but the controlled search group did not. These results support the hypothesis that allocation of attentional resources to external cues can influence the processing of food cues.

Adult↗

PubMed1996

The association of maternal psychopathology and family socioeconomic status with psychological problems in obese children.

In an earlier study we found parental psychiatric symptoms to be a better correlate of behavioral problems in obese children than either child or parental obesity. This study sought to extend this research by assessing the association of general maternal distress, specific maternal psychopathology, family socioeconomic status and child obesity with the psychological problems of 152 children seeking treatment for obesity in two cohorts. Child psychological problems were measured using the Child Behavior Checklist/4-18 (CBCL) in each cohort. In sample 1 maternal general psychiatric symptoms were measured using the Cornell Medical Index (psychiatric subscales) and the Inventory of Interpersonal Problems whereas specific psychopathology was assessed with the Beck Depression Inventory and the Bulimia Test. In sample 2 the Symptom Checklist-90 and Binge Eating Scale provided general and specific measures of psychopathology. In the combined sample, 58% percent of the boys and 44% of the girls met criteria on at least one CBCL behavioral problem scale, with Social Problems the most prevalent problem in both boys and girls. For both samples, child obesity did not account for any variance in child psychosocial problems beyond that accounted for by maternal psychopathology and family SES. Family SES accounted for a significant increment in variance in child behavioral problems in only two scales. This study systematically replicates previous research, adding support for a broader conceptualization of factors that influence psychological problems in obese treatment-seeking children than one which focuses on child obesity.

Adult↗

PubMed1996

Reinforcing value of food in obese and non-obese women.

Food is a powerful reinforcer, and individual differences in the reinforcing efficacy of food may provide a mechanism to explain the excess intake and positive energy balance responsible for obesity. The present study tested the hypothesis that eating palatable food would be more reinforcing than engaging in sedentary activities (e.g. playing computer games) for obese in comparison to non-obese non-dietary restrained female college students. Subjects could choose to eat food or engage in sedentary activities based on their responding in a computer-generated concurrent schedules task. The reinforcement schedule associated with earning access to sedentary activities was held at variable ratio 2 (VR2) while the food reinforcement schedule was set at VR2 in the first trial of the choice task and doubled across the four subsequent trials from VR4 to VR32. Choice and consumption results indicated that eating was significantly more reinforcing than engaging in sedentary activities for obese subjects than non-obese subjects. Hedonics for the activities and foods were not correlated with total food reinforcers earned and did not differ between the groups. These results confirm the hypothesis that eating food is more reinforcing than selected alternative activities to a greater extent for obese than for non-obese young women.

Adult↗

PubMed1996

Changes in taste and satiety in dietary-restrained women following stress.

Stress has been shown to increase food consumption in women with high levels of dietary restraint (restrainers) but decrease consumption in nonrestrainers. The present study was designed to replicate the differential eating pattern following stress and measure physiological and subjective responses to food over repeated taste presentations. Restrained (N = 16) and nonrestrained (N = 16) women were given eight taste presentations of a food followed by an ad lib taste test. Between taste trials, half of the restrainers and nonrestrainers performed a variation of the Stroop stressor while remaining subjects sat quietly. Salivation to the food cue was measured at each trial as well as ratings of food liking, hunger, fullness, and arousal. Results showed significant effects of restraint on food liking and stress condition on hunger. Restrainers increased liking ratings over taste trials whereas ratings for nonrestrainers increased and then decreased to baseline levels by the last trial (p = 0.05). Nonstressed subjects showed an increase in hunger ratings, whereas ratings for stressed subjects did not show any stable directional pattern (p = 0.04). Salivary responses decreased for all groups (p = 0.01). A significant interaction of restraint by stress for intake was found (p = 0.03); restrainers increased consumption following stress whereas nonrestrainers decreased consumption as compared with controls. The data suggest that the Stroop task can influence intake in restrainers, but the changes in intake did not directly correspond to the changes observed during the presentations of the taste cues and stressor.

Adolescent↗

PubMed1996

Exercise in treating obesity in children and adolescents.

This paper reviews the use of exercise programs with obese children and adolescents. Studies included for review met two criteria: 1) children or adolescents were defined as obese using objective criteria for obesity, and 2) obese children or adolescents were provided either different types of exercise programs or an exercise program compared with a no-exercise control condition. Thirteen controlled outcome studies were identified. Experimental design, methods, and outcomes are presented and evaluated for each study. Factors that should be considered in research testing exercise interventions are discussed, including adherence, diet, age, gender, and type of exercise. In addition, the potential for exercise programs in the prevention of obesity in childhood and adolescence is discussed. The results support the continued use of exercise in combination with diet for child and adolescent obesity treatment, but the limited number of controlled studies indicates the need for more research in the area. The potential for exercise programs in the prevention of obesity in childhood and adolescence is discussed.

Adolescent↗

PubMed1996

Determinants of physical activity in obese children assessed by accelerometer and self-report.

Previous research has shown that predictors of activity in adults depend upon the method of measurement. This study is designed to assess the predictors of activity in a sample of 59 obese children. Activity was measured using self-reported and TriTrac accelerometer METs. Self-report and TriTrac accelerometer measures were moderately correlated, r = 0.46, with the self-reported activity (2.3 METs) significantly greater than TriTrac (1.6 METs). Hierarchical regression analysis examined the influence of socioeconomic level, body composition, fitness, hedonics of child and adult activity behaviors, and decisional balance on self-reported and accelerometer-measured activity, controlling for child and parent psychopathology. Child and parent psychological symptoms accounted for 8.3% and 3.4% of the variance in accelerometer and self-reported METs, respectively. The model for accelerometer-measured activity showed socioeconomic level and parent self-report of activity accounted for 14.8% of the incremental variance in child activity. The model for self-report of child activity found that child fitness accounted for 23.5% of the incremental variance in child activity. These results suggest that the predictors of activity level are different based upon the method of measurement, consistent with research in adults.

Activities of Daily Living↗

PubMed1996

Family-based behavioural intervention for obese children.

The family environment can contribute to the development of obesity. Parenting styles may influence the development of food preferences and the ability of a child to regulate intake. Parents and other family members arrange a common, shared environment that may be conducive to overeating or a sedentary lifestyle. Family members serve as models, and reinforce and support the acquisition and maintenance of eating and exercise behaviours. Family-based interventions are needed to modify these variables in treating obese children. We have made significant progress in developing interventions that target obese 8-12 year-old children, completing four 10-year follow-up studies that provide support for two factors that are useful in childhood obesity treatment. First, our research suggests that the direct involvement of at least one parent as an active participant in the weight loss process improves short- and long-term weight regulation. Second, our research suggests that increasing activity is important for maintenance of long-term weight control. Correlational analyses on the 10-year database suggest that family and friend support for behaviour change are related to long-term outcome. Family-based obesity treatment provides interventions for both children and their parents, but children benefit more from treatment than their parents. These positive results provide an encouraging basis for optimism that further development of interventions, based on newer research on family processes and behaviour changes, can be useful in treating childhood obesity.

Adult↗

PubMed1995

Do children lose and maintain weight easier than adults: a comparison of child and parent weight changes from six months to ten years.

Recent research has shown weight maintenance for obese preadolescent children over 60 and 120 month intervals, while studies on adults consistently show they fail to maintain weight loss. This paper is designed to examine differences in percent overweight changes at 6, 60 and 120 months in obese parents and children from 113 families who participated in randomized controlled outcome studies evaluating family-based behavioral treatment. Analyses showed children had significantly greater changes in percent overweight than their parents at each time point. Chi-Square and Logistic Regression analyses showed children were more likely than their parents at each time point to have percent overweight decreases greater than 20%, with over 20% of the children and less than 1% of the parents showing changes this large. The implications of these results for weight control are discussed. These results suggest there may be differences in the efficacy of treating obesity in children versus adults.

Adult↗

PubMed1995

Different methods of assessing nicotine-induced antinociception may engage different neural mechanisms.

Two methods were used to assess nicotine-induced antinociception: tail withdrawal from a hot water bath and hind paw withdrawal from a hotplate. Nicotine doses which produced 75-80% maximum response were 0.75 mg/kg (free base) for tail withdrawal and 0.35 mg/kg for paw withdrawal. The peripheral blocker chlorisondamine (0.1 mg/kg, SC) and the central antagonist, mecamylamine (1 mg/kg, SC) were each effective in blocking nicotine-induced increases in tail withdrawal latencies, suggesting that this effect of nicotine depends on either the action of nicotine at peripheral receptors or the functional integrity of those receptors. In contrast, nicotine-induced increases in paw withdrawal latencies were blocked by mecamylamine but not by chlorisondamine, even at other agonist/antagonist dose combinations. The results indicate that these two effects of nicotine involve at least partially separate pathways and may reflect a different mix of the antinociceptive and motor depressing effects of nicotine.

Analgesia↗

PubMed1995

Gender, dietary restraint, and smoking's influence on hunger and the reinforcing value of food.

Smoking may enhance satiety following meal consumption, thereby reducing subsequent eating (i.e., between-meal snacks), especially in women high in dietary restraint. Female smokers (n = 20, 10 high and 10 low restraint) and male smokers (n = 10) participated in two sessions, involving overnight abstinence from food and smoking (smoking abstinence day) or from food only (smoking day), in a within-subjects design. The reinforcing value of food was determined by the number of responses made to obtain food reinforcers (100-kcal snack portions) vs. money using a concurrent schedules computer task. Subjects were given a small caloric load on each day followed by access to food vs. money. On the smoking day, subjects were allowed to smoke every 30 min during the session as well as ad lib before the session. Self-reported hunger was also assessed upon arrival (after fasting) and following the caloric load during each session. Results indicated no effect of smoking on initial hunger rating, after fasting, but hunger ratings following the caloric load declined significantly more during smoking vs. abstinence days for all subjects, consistent with an enhancement of postmeal satiety due to smoking. There was no overall main effect of smoking on food-reinforced responding. However, responding for food was significantly less during the smoking vs. abstinence days for high-restraint females only and not for low-restraint females or for males. These findings indicate that smoking's acute influence on reducing food intake does not reflect a broad gender difference but may be specific to dietary restraint.

Adolescent↗

PubMed1995

Physiological and subjective responses to food cues as a function of smoking abstinence and dietary restraint.

Dietary restraint is a characteristic associated with greater increase in food intake after smoking cessation, and salivation is a marker of physiological responsiveness to food that may be influenced by cessation. The present study examined the effect of brief smoking abstinence (16 h) vs. no abstinence on salivary and subjective responses to food taste cues in women smokers high vs. low in dietary restraint (n = 10 each). On each of two days (smoking abstinence vs. nonabstinence), salivary volume was assessed during each of 10 trials involving presentation of a small sample of strawberry yogurt. Decline in salivation over trials is indicative of habituation, or reduction in physiological responsiveness to taste cues, and may be a marker of satiety. Subjects also completed self-report measures of hunger, taste liking, desire for cigarette, and emotional arousal during each trial. A 10-min period of ad lib consumption of yogurt ended each session. Results showed significantly elevated salivary response to the first trial of taste exposure in high vs. low restraint women, especially on the smoking day. Moreover, salivary habituation was significantly disrupted by smoking abstinence, especially over the first 5 trials, in high restraint but not low restraint women. High restraint women also reported increasing desire for cigarette and emotional arousal across food taste trials on both days, while low restraint women reported no change in each over trials. There were no differences in ad lib yogurt consumption. These results indicate that brief smoking abstinence attenuates salivary habituation to taste in high restraint women, suggesting a marker for processes responsible for increased food intake after quitting smoking.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1995

Effects of decreasing sedentary behavior and increasing activity on weight change in obese children.

Obese children 8-12 years old from 61 families were randomized to treatment groups that targeted increased exercise, decreased sedentary behaviors, or both (combined group) to test the influence of reinforcing children to be more active or less sedentary on child weight change. Significant decreases in percentage overweight were observed after 4 months between the sedentary and the exercise groups (-19.9 vs. -13.2). At 1 year, the sedentary group had a greater decrease in percentage overweight than did the combined and the exercise groups (-18.7 vs. -10.3 and -8.7) and greater decrease in percentage of body fat (-4.7 vs. -1.3). All groups improved fitness during treatment and follow-up. Children in the sedentary group increased their liking for high-intensity activity and reported lower caloric intake than did children in the exercise group. These results support the goal of reducing time spent in sedentary activities to improve weight loss.

Child↗

PubMed1995

Effects of reinforcing increases in active behavior versus decreases in sedentary behavior for obese children.

This experiment tested the effects of reinforcing obese children lo be more active or less sedentary in their choice of active versus sedentary behaviors. On days I and 5, there were no contingencies for sedentary or active behaviors. During days 2 through 4, children in the Activity group were reinforced for being more active, and they significantly increased their activity and decreased time spent on preferred sedentary activities. Children in the Sedentary group were reinforced for not engaging in preferred sedentary behaviors, and they significantly decreased time spent on these sedentary behaviors, with lime reallocated both to being more active and to substitution of lower preference sedentary behaviors. Children randomized to the Control group were reinforced for attendance and made choices among the alternatives as usual, allocating most or their time during all 5 days for their preferred sedentary behaviors. These laboratory results support the idea that activity can be increased by either reinforcing children for being more active or for reducing lime spent in sedentary activities.

Journal Article↗

PubMed1995

Exercise in the treatment of childhood obesity.

Research on exercise in the treatment of childhood obesity is reviewed. The role of activity or sedentary behaviors in the development of obesity is discussed, with a conceptual model for understanding choice of being sedentary or active presented. Research that assesses the effects of exercise alone and diet plus exercise on child weight control are reviewed, as well as new research on modifying access to sedentary behaviors. Treatment research suggests exercise alone is not sufficient, with the combination of diet plus exercise more effective for long-term than short-term changes. Finally, suggestions for new research are presented.

Adolescent↗