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Biomedical subjects

Andrea S Chambers

Publications and source records attributed to Andrea S Chambers.

7 recordsLinked to original sources
PubMed2007

Sex differences in cardiac vagal control in a depressed sample: implications for differential cardiovascular mortality.

Previous studies suggest depression is a risk factor for all cause mortality, with depressed men at greater risk than depressed women. Diminished cardiac vagal control (CVC) in depressed patients has also been found to increase risk of cardiac mortality. Previous research found that depressed women have higher CVC than depressed men suggesting CVC might be related to the discrepancy in mortality rates between depressed men and women. This finding, however, was in the context of a study with several methodological weaknesses. The current study sought to replicate the sex difference in CVC in a sample of 137 medically healthy and clinically diagnosed depressed patients. Main effects of sex and age significantly predicted CVC such that depressed women had greater CVC and CVC decreased with age in the cross-sectional sample. The results suggest greater CVC in depressed women might confer cardioprotective functions, which may partially explain the sex difference in mortality rates in the depressed population.

Adult↗
PubMed2006

Evaluation of guided imagery as treatment for recurrent abdominal pain in children: a randomized controlled trial.

BACKGROUND: Because of the paucity of effective evidence-based therapies for children with recurrent abdominal pain, we evaluated the therapeutic effect of guided imagery, a well-studied self-regulation technique. METHODS: 22 children, aged 5-18 years, were randomized to learn either breathing exercises alone or guided imagery with progressive muscle relaxation. Both groups had 4-weekly sessions with a therapist. Children reported the numbers of days with pain, the pain intensity, and missed activities due to abdominal pain using a daily pain diary collected at baseline and during the intervention. Monthly phone calls to the children reported the number of days with pain and the number of days of missed activities experienced during the month of and month following the intervention. Children with < or = 4 days of pain/month and no missed activities due to pain were defined as being healed. Depression, anxiety, and somatization were measured in both children and parents at baseline. RESULTS: At baseline the children who received guided imagery had more days of pain during the preceding month (23 vs. 14 days, P = 0.04). There were no differences in the intensity of painful episodes or any baseline psychological factors between the two groups. Children who learned guided imagery with progressive muscle relaxation had significantly greater decrease in the number of days with pain than those learning breathing exercises alone after one (67% vs. 21%, P = 0.05), and two (82% vs. 45%, P < 0.01) months and significantly greater decrease in days with missed activities at one (85% vs. 15%, P = 0.02) and two (95% vs. 77%. P = 0.05) months. During the two months of follow-up, more children who had learned guided imagery met the threshold of < or = 4 day of pain each month and no missed activities (RR = 7.3, 95%CI [1.1,48.6]) than children who learned only the breathing exercises. CONCLUSION: The therapeutic efficacy of guided imagery with progressive muscle relaxation found in this study is consistent with our present understanding of the pathophysiology of recurrent abdominal pain in children. Although unfamiliar to many pediatricians, guided imagery is a simple, noninvasive therapy with potential benefit for treating children with RAP.

Abdominal Pain↗
PubMed2006

The many metrics of cardiac chronotropy: a pragmatic primer and a brief comparison of metrics.

This paper focuses on pragmatic issues in obtaining measures of cardiac vagal control, and overviews a set of freely available software tools for obtaining several widely used metrics that putatively reflect sympathetic and/or parasympathetic contributions to cardiac chronotropy. After an overview of those metrics, and a discussion of potential confounds and extraneous influences, an empirical examination of the relationships amongst these metrics is provided. This study examined 10 metrics in 96 unselected college students under conditions of resting baseline and serial paced arithmetic. Intercorrelations between metrics were very high. Factor analyses were conducted on the metrics reflecting variability in cardiac rate, once at baseline and again during mental arithmetic. Factor structure was highly stable across tasks, and included a factor that had high loadings of all variables except Toichi's "cardiac sympathetic index" (CSI), and a second factor that was defined predominantly by the CSI. Although generally highly correlated, the various metrics responded differently under challenge.

Arrhythmia, Sinus↗
PubMed2006

Acupuncture for depression: a randomized controlled trial.

OBJECTIVE: To assess the efficacy of acupuncture as an intervention for major depressive disorder (MDD). METHOD: Acupuncture was examined in 151 patients with MDD (DSM-IV) who were randomly assigned to 1 of 3 groups in a double-blind randomized controlled trial. The specific intervention involved Traditional Chinese Medicine (TCM)-style acupuncture with manual stimulation for depression; the control conditions consisted of (1) a nonspecific intervention using a comparable number of legitimate acupuncture points not specifically targeted to depressive symptoms and (2) a waitlist condition, which involved waiting without intervention for 8 weeks. After 8 weeks, all patients received the depression-specific acupuncture. Each 8-week intervention regimen consisted of 12 acupuncture sessions delivered in an acupuncturist's office in the community. The primary outcome measure was the 17-item Hamilton Rating Scale for Depression. The study was conducted from February 1998 to April 2002. RESULTS: Twenty patients terminated treatment before the completion of the 8-week intervention (13%) but not differentially by study group. Random regression models of the intent-to-treat sample revealed that although patients receiving acupuncture improved more than those awaiting intervention, no evidence of differential efficacy of the depression-specific over nonspecific intervention was found. Response rates in acupuncture-treated patients were relatively low after 8 weeks (22% and 39% for specific and nonspecific intervention groups, respectively), with the response rate after the entire 16-week trial reaching 50%. CONCLUSION: Although TCM manual acupuncture is a well-tolerated intervention, results fail to support its efficacy as a monotherapy for MDD. It can't be ruled out that factors unique to the implementation of acupuncture in this research study may have limited the efficacy of interventions compared to those provided in naturalistic settings. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov identifier NCT00010517.

Acupuncture↗
PubMed2002

Vagal tone as an indicator of treatment response in major depression.

Increased vagal tone has been associated with treatment success using pharmacological agents and cognitive-behavioral treatment in major depression, but not using electroconvulsive therapy. The present study investigated whether increases in vagal tone would be associated with favorable treatment response with nonpharmacological treatment. At baseline and following treatment, 16 subjects were administered the Hamilton Rating Scale for Depression (HRSD) followed by electrocardiographic recording. Those with little change in vagal tone from before to after treatment showed minimal reduction in HRSD score (-4.8); those with larger vagal tone change showed a large decrease in HRSD score (-14.8). Changes in vagal tone are thus related to favorable treatment response in depression, and do not represent anticholinergic pharmacological effects. Future work manipulating vagal tone might prove informative in teasing apart the causal role of vagal tone and depression.

Acupuncture Therapy↗
PubMedDate not supplied

Patients' perception of their depressive illness.

Perception of illness has been described as an important predictor in the medical health psychology literature, but has been given little attention in the domain of mental disorders. The patient's Perception of Depression Questionnaire (PDIQ) is a newly developed measure whose factor structure and psychometric properties were evaluated on a sample of 174 outpatients meeting criteria for major depressive disorder. The clinical utility of the questionnaire was assessed on a sub-sample of 121 participants in a study of acupuncture treatment for depression. The questionnaire has four subscales, each with high internal consistency and high test-retest reliability. These four subscales are: Self-Efficacy, which reflects perceived controllability of the illness, Externalizing, which reflects attributing the illness to external causes, Hopeless/Flawed, which reflect a belief that depression is a personal trait and therefore there is little hope for cure, and Holistic, which reflects a belief in alternative therapies. Although the PDIQ did not predict outcome, its subscales were related to adherence to treatment, treatment preference, expectations, and therapeutic alliance. The subscales have adequate convergent/discriminant validity and are clinically relevant to aspects of treatment provision.

Adult↗