Assessment of the motivation to use artificial sweetener among individuals with an eating disorder
Eating disorders are associated with a range of abnormalities in eating behavior. Some individuals consume large amounts of non-caloric artificial sweeteners, suggesting abnormalities in appetitive responding. The current study aimed to quantify hedonic and motivating effects of artificial sweetener in individuals with and without an eating disorder. Two laboratory studies were conducted. Hedonic preference was estimated using the number of artificial sweetener packets (0-10) added to unsweetened cherry flavored Kool-Aid (study 1). Motivation to obtain sweetener was assessed by a progressive ratio (PR) work task (study 2). Ninety-three participants (25 anorexia nervosa restricting type (AN-R), 23 AN binge/purge type (AN-B/P), 20 bulimia nervosa (BN), and 25 normal controls (NC)) completed the study. No significant difference in hedonic preference was found among participant groups. Work completed at the PR task ranged from 0 to 9500 key-board presses. The AN-B/P group had a significantly higher breakpoint and performed significantly more work for sweetener compared to the BN and NC groups. Among AN-B/P and AN-R participants, the preferred number of Equal packets was significantly correlated with the breakpoint and total work. The increased amount of work for sweetener among individuals with AN-B/P supports an enhanced reward value of sweet taste in this population, and suggests that the characteristic food avoidance in AN cannot be accounted for by decreased reward value of all taste-related stimuli. This study also supports the novel application of a PR ratio task to quantify the motivating effect of sweet taste among individuals with an eating disorder.
Measurement of fidgeting in patients with anorexia nervosa using a novel shoe-based monitor
OBJECTIVE: To objectively assess seated non-exercise physical activity in patients with anorexia nervosa (AN) relative to healthy controls (HCs) and examine the associations between this physical activity, eating disorder pathology, and levels of anxiety and depression. METHOD: Eleven inpatients with AN and 10 HCs wore a shoe-based accelerometer (SmartShoe) at three time points: a) while eating lunch, b) filling out questionnaires, and c) watching television for 1h. RESULTS: Across all three tasks, patients with AN were significantly more active than HCs, thereby engaging in a greater degree of restless or fidgeting behavior. Degree of physical activity was positively correlated with eating disorder psychopathology in the sample with AN, and a trend towards a positive association between physical activity and levels of depression and anxiety was also found in this sample. Among individuals with AN, physical activity was not significantly correlated with BMI, duration of illness, or number of days since hospital admission. DISCUSSION: Use of a minimally invasive, shoe-based monitor revealed patients with AN engaged in a greater degree of fidgeting relative to HCs during quiet, seated tasks and this heightened activity was related to measures of pathology. Non-exercise physical activity, including fidgeting, may warrant further clinical attention in this patient population.
The reinforcing effect of exercise in anorexia nervosa: Clinical correlates and relationship to outcome
The purpose of the current study was to examine the relative reinforcing effect of exercise compared to a non-monetary alternative reinforcer (leisure activity), and to money, before and after weight restoration in an inpatient population with anorexia nervosa (AN). Sixty-two inpatients with AN completed a progressive ratio (PR) task to earn exercise, leisure activities, or cash at low weight and after weight restoration. Measures of pathology and motivation to exercise were completed and post-treatment discharge weights were collected. Patients worked harder for exercise at low weight than after weight restoration (df = 46, t = 5.50, p < .001). PR task performance was weakly associated with a measure of commitment to exercise (low weight: r = 0.31, weight restored: r = 0.36, p < .05), but not with other clinical measures or follow-up weights. Contrary to prior suggestions, measurement of the reinforcing value of exercise among individuals with AN via a PR task does not appear valuable in assessing clinical severity or outcome. Other, simpler, self-report measures of commitment to exercise may have greater value in assessing these outcomes.
Physical activity and post-treatment weight trajectory in anorexia nervosa
OBJECTIVE: This study compared an objective measurement of physical activity (PA) in individuals with anorexia nervosa (AN) at low-weight, weight-restored, and post-treatment time points, and also compared PA in AN with that of healthy controls (HC). METHOD: Sixty-one female inpatients with AN wore a novel accelerometer (the IDEEA) which measured PA at three time points: a) low-weight, b) weight-restored, and c) one month post-hospital discharge. Twenty-four HCs wore the IDEEA at one time point. RESULTS: Inpatients with AN became more physically active than they were at low-weight at weight restoration and following treatment discharge. Post-treatment patients with AN were more physically active than HCs during the day and less active at night, which was primarily accounted for by amount of time spent on feet, including standing and walking. Greater time spent on feet during the weight-restoration time point of inpatient treatment was associated with more rapid decrease in BMI over the 12 months following treatment discharge. Fidgeting did not differ between patients and controls, did not change with weight restoration, and did not predict post-treatment weight change. DISCUSSION: Use of a novel accelerometer demonstrated greater PA in AN than in HC. PA following weight restoration in AN, particularly time spent in standing postures, may contribute to weight loss in the year following hospitalization. (c) 2015 Wiley Periodicals, Inc. (Int J Eat Disord 2015).
Assessment of fat taste in individuals with and without anorexia nervosa
OBJECTIVE: Avoidance of dietary fat is a highly characteristic eating behavior of individuals with anorexia nervosa (AN). To date, no study has determined whether these individuals are better able to perceive the fat content of foods than individuals without AN. The goal of this study was to compare blinded taste ratings of fat-free, low fat, and regular cream cheese in patients with AN and in normal controls (NC). METHOD: AN (n = 25) and control (NC; n = 25) participants were presented with a series of nine cream cheese samples of three differing fat contents and asked to taste and rate each sample from very low to very high fat. RESULTS: Repeated measures ANOVA found no significant main effect of fat content and no interaction between fat content and diagnosis; however, a significant three-way interaction between fat content, diagnosis, and trial was observed. Post hoc analysis revealed a significant fat content by trial interaction within the AN group, suggesting a significant trial effect for the fat-free samples only with improving ability to detect fat-free samples over repeated trials. DISCUSSION: The current study suggests that individuals with AN do not have a markedly greater ability to taste fat than NC, and that; therefore, fat avoidance is likely primarily based on cognitive factors.
Android TWEETY - A wireless activity monitoring and biofeedback system
Validation of two novel monitoring devices to measure physical activity in healthy women
Piscataway : IEEE Press Books, 2014
Adipose tissue distribution after weight restoration and weight maintenance in women with anorexia nervosa
BACKGROUND: Body image distortions are a core feature of anorexia nervosa (AN). We, and others, previously reported abnormalities in adipose tissue distribution after acute weight restoration in adult women with AN compared with body mass index-matched healthy control women. Whether these abnormalities persist over time remains unknown. OBJECTIVES: We aimed to 1) replicate previous findings that showed preferential central accumulation of adipose tissue in recently weight-restored AN women compared with control subjects, 2) describe the change within patients with longer-term (1-y) weight maintenance, and 3) compare adipose tissue distribution after 1-y maintenance with that of control subjects. DESIGN: Body composition and adipose tissue distribution were assessed by whole-body magnetic resonance imaging in women with AN shortly after weight normalization (n = 30) and again 1 y after hospital discharge (n = 16) and in 8 female control subjects at 2 time points. RESULTS: With acute weight restoration, AN patients had significantly greater visceral and intermuscular adipose tissue compared with control women [visceral: 0.75 +/- 0.26 compared with 0.51 +/- 0.26 kg in AN patients and controls, respectively (P = 0.02); intermuscular: 0.46 +/- 0.17 compared with 0.29 +/- 0.13 kg in AN patients and controls, respectively (P = 0.01)]. With maintenance of normal weight for approximately 1 y, visceral adipose tissue distribution in AN patients was not different from that in healthy control subjects. CONCLUSIONS: In adult women with AN, normalization of weight in the short term is associated with a distribution of adipose tissue that is consistent with a central adiposity phenotype. This abnormal distribution appears to normalize within a 1-y period of weight maintenance. This research was registered at clinicaltrials.gov as NCT 00271921 and NCT 00368667.
Relative reinforcing value of exercise in inpatients with anorexia nervosa: model development and pilot data
OBJECTIVE: This study sought to quantify, among patients hospitalized for the treatment of anorexia nervosa (AN), the reinforcing value of exercise, defined as the amount of work a patient would expend for the opportunity to exercise. METHOD: Sixteen inpatients with AN performed a computerized progressive ratio (PR) task for the opportunity to exercise for either 15 or 30 min, or a monetary voucher. Exercise "breakpoint" was calculated and compared with clinical measures. RESULTS: Patients performed an average of 1134.4 (+/-751.2) button presses for exercise. Exercise breakpoint was significantly correlated with the Beck Depression Inventory (BDI; r = .728, p = .001), and there was a trend toward a correlation with the Commitment to Exercise Scale (CES; Davis, 1993; r = .490, p = .054). CONCLUSION: Results support the feasibility and potential utility of this novel application of the PR task to quantify the reinforcing value of exercise in AN. The association between exercise and depression is consistent with some prior studies in AN. The trend toward an association with CES scores suggests that breakpoint captures an aspect of the motivation for exercise in this population.
Physical activity and cortisol in anorexia nervosa
Elevated physical activity is commonly observed among patients with Anorexia Nervosa (AN) and can manifest in several forms. While elevated physical activity may play a key role in the pathophysiology of this disorder, much remains unknown about it, including the relationship among its various manifestations, and their underlying mechanism(s). The purposes of the current study were to (1) quantify locomotor activity in inpatients with AN using an accelerometer, (2) determine the association between locomotor activity and exercise history and (3) determine the association between urinary cortisol and physical activity. Thirty-six women hospitalized with AN wore activity armbands for 48 h during the first 2 weeks of hospitalization, collected 24-h urine to measure cortisol, and completed rating forms. Activity counts varied more than four-fold among individuals but were consistent within individuals over the 2 monitoring days (p<0.001). Averaged 24-h activity counts were positively correlated with pre-hospitalization attitude towards exercise as measured by the Commitment to Exercise Scale (CES; p=0.032). Forty-two percent of women reported "high" exercise in the 3 months before hospitalization; compared to non-high-exercising patients, these women demonstrated a higher CES score (p<0.001) and a trend toward greater activity counts (p=0.059). Urinary cortisol was positively associated with activity counts (p=0.044) and CES score (p=0.018). These data suggest that some women with AN have a higher "drive" for physical activity that persists into early hospitalization. HPA axis abnormalities may be associated with this state.