Biomedical subjects

Blaine Ditto

Publications and source records attributed to Blaine Ditto.

At least 19 recordsLinked to original sources

PubMed2006

Asthma self-efficacy, high frequency heart rate variability, and airflow obstruction during negative affect in daily life.

BACKGROUND: Emotional stress has been considered an important asthma trigger for years, though the mechanisms by which stress may exacerbate asthma remain poorly understood. The stress-asthma morbidity association could occur through cognitive-behavioral pathways, such as decreased asthma self-efficacy and disorganized self-care, or through the more direct physiological effects of stress on autonomic (parasympathetic) nervous system activity. No study has examined how these two mechanisms may interact to contribute to greater airflow obstruction during emotional stress in daily life. This study investigated associations between peak expiratory flow rate (PEFR) and high frequency heart rate variability (HFHRV) during periods of negative affect and physical activity in daily life in patients with higher versus lower asthma self-efficacy scores. METHODS: Fifty-three patients with mild to moderate asthma completed the Asthma Self-Efficacy Scale (ASES) and underwent a 15 h ambulatory assessment of daytime HFHRV and PEFR, while completing self-report diaries of their physical activities and affect. RESULTS: In patients with lower asthma self-efficacy scores, increased levels of negative affect during daily life were associated with higher levels of HFHRV and decreased PEFR relative to patients with higher asthma self-efficacy scores. Increased levels of physical activity were associated with decreased levels of HFHRV irrespective of asthma self-efficacy scores. CONCLUSIONS: Findings suggest that lower asthma self-efficacy may be associated with increased parasympathetic activity and airflow obstruction during periods of negative affect during daily life.

Activities of Daily Living↗

PubMed2006

The effects of applied tension on symptoms in French-speaking blood donors: a randomized trial.

Blood-donation-related symptoms such as dizziness and weakness discourage people from participating in this important health-related activity. Four hundred sixty-seven young adult, French-speaking blood donors were randomly assigned to (a) a condition in which they learned a possible preventive technique called applied tension and were asked to practice it from the time they got on the donation chair until they were just about to get up, (b) a placebo condition in which they learned applied tension and were asked to practice it from the time they got on the chair until the insertion of the donation needle, or (c) a no-treatment control condition. Donors assigned to the treatment condition reported significantly fewer blood-donation-related symptoms than did donors assigned to the other conditions and rated their likelihood of returning to give blood again as greater than did those in the no treatment condition. Among donors whose chairs were not reclined, participants in the treatment condition had significantly smaller heart rate reactions to blood donation than did those in the other conditions.

Adult↗

PubMed2006

Vasovagal symptoms mediate the relationship between predonation anxiety and subsequent blood donation in female volunteers.

BACKGROUND: Although not universal, a certain amount of predonation anxiety is common and not surprising among inexperienced blood donors. Variations in predonation anxiety, however, may influence the donor's experience in several respects and might be related to the likelihood of subsequent donation even among those who do not report particularly high levels of anxiety. STUDY DESIGN AND METHODS: A total of 671 inexperienced blood donors (zero or one prior donation) enrolled in a treatment study and completed questionnaires assessing anxiety before and after giving blood. Ratings of pain and blood donation-related symptoms were obtained after giving blood, as well as information from the nurses about the blood donation procedure. Follow-up information on number of additional visits to a blood collection clinic during the subsequent year was also obtained for most participants. RESULTS: Predonation anxiety was positively related to ratings of blood donation-related symptoms and chair reclining by the nurses and negatively related to the donor's rating, obtained at the end of the procedure, of the likelihood that he or she would give blood again. Women, but not men, with higher predonation anxiety were significantly less likely to return to a blood clinic in the following year. The results of mediation analyses suggest that this was due to the association between anxiety and donation-related symptoms. CONCLUSION: The results do not indicate whether or not it is feasible or useful to modify predonation anxiety, but highlight the relationships between the emotional state of inexperienced donors and several aspects of the donation experience, including subsequent donor return. Further study of the psychosocial aspects of blood donation and examination of related research (e.g., treatment of dental anxieties) may be worthwhile.

Anxiety↗

PubMed2006

Neuropsychological characteristics of adolescent boys differing in risk for high blood pressure.

BACKGROUND: Individuals with established hypertension have been found to display deficits in a number of neuropsychological abilities. In general, these are probably due to structural changes in the brain produced by sustained high blood pressure. However, a potentially important line of research suggests that some of these deficits may extend to younger individuals with less severe elevations of blood pressure, perhaps even children, and thus be related more to risk for hypertension than hypertension per se. PURPOSE: The objective was to examine the relationships between neuropsychological function and risk for hypertension in children. METHODS: Measurements of blood pressure and parental history of hypertension were obtained in 88 French-Canadian 14-year-old boys and used to predict performance on a neuropsychological battery. RESULTS: Boys at greater risk of hypertension by virtue of having a parental history of high blood pressure and normatively elevated systolic blood pressure had significantly lower scores on a verbal learning factor score compared to boys at lower risk. Boys with normatively elevated systolic blood pressure also had significantly lower scores on a spatial learning and memory factor score compared to boys with lower blood pressure. The results could not be attributed to differences in family socioeconomic status. CONCLUSIONS: Using a younger sample than typically employed in the area, the results support previous suggestions that some of the neuropsychological characteristics displayed by hypertensive individuals may predate the development of clinically elevated blood pressure and could be associated with risk for the disorder.

Adolescent↗

PubMed2006

Short-term autonomic and cardiovascular effects of mindfulness body scan meditation.

BACKGROUND: Recent research suggests that the Mindfulness-Based Stress Reduction program has positive effects on health, but little is known about the immediate physiological effects of different components of the program. PURPOSE: To examine the short-term autonomic and cardiovascular effects of one of the techniques employed in mindfulness meditation training, a basic body scan meditation. METHODS: In Study 1, 32 healthy young adults (23 women, 9 men) were assigned randomly to either a meditation, progressive muscular relaxation or wait-list control group. Each participated in two laboratory sessions 4 weeks apart in which they practiced their assigned technique. In Study 2, using a within-subjects design, 30 healthy young adults (15 women, 15 men) participated in two laboratory sessions in which they practiced meditation or listened to an audiotape of a popular novel in counterbalanced order. Heart rate, cardiac respiratory sinus arrhythmia (RSA), and blood pressure were measured in both studies. Additional measures derived from impedance cardiography were obtained in Study 2. RESULTS: In both studies, participants displayed significantly greater increases in RSA while meditating than while engaging in other relaxing activities. A significant decrease in cardiac pre-ejection period was observed while participants meditated in Study 2. This suggests that simultaneous increases in cardiac parasympathetic and sympathetic activity may explain the lack of an effect on heart rate. Female participants in Study 2 exhibited a significantly larger decrease in diastolic blood pressure during meditation than the novel, whereas men had greater increases in cardiac output during meditation compared to the novel. CONCLUSIONS: The results indicate both similarities and differences in the physiological responses to body scan meditation and other relaxing activities.

Adult↗

PubMed2006

What is worse for asthma control and quality of life: depressive disorders, anxiety disorders, or both?

BACKGROUND: The high burden of asthma appears to be related to poor asthma control. Although previous studies have reported associations between depressive disorders (DDs) and anxiety disorders (ADs) and worse asthma control and quality of life, the relative impact of these disorders on asthma control and quality of life has not been explored. This study evaluated the relative impact of having a DD and/or AD on asthma control and quality of life. METHOD: Five hundred four consecutive adults with confirmed, physician-diagnosed asthma underwent a brief, structured psychiatric interview using the Primary Care Evaluation of Mental Disorders. Asthma control and asthma-related quality of life were assessed using the Asthma Control Questionnaire (ACQ) and the Asthma Quality of Life Questionnaire (AQLQ). All patients underwent standard spirometry. RESULTS: Thirty-one percent of patients (n = 157) met the diagnostic criteria for one or more psychiatric disorders (8% had DD only, 12% had AD only, and 11% had both). Analyses revealed independent effects for DDs on total ACQ scores (p < 0.01), and for DDs and ADs on total AQLQ scores and all four AQLQ subscales (p < 0.05). There were no interaction effects. CONCLUSIONS: Results suggest that DDs and ADs are associated with worse asthma-related quality of life, but only DDs are associated with worse asthma control. Interestingly, having both a DD and an AD did not confer additional risk for worse asthma control or quality of life. Physicians may want to consider the differential impact of negative mood states when assessing levels of asthma control and quality of life.

Adult↗

PubMed2005

Higher BMI is associated with worse asthma control and quality of life but not asthma severity.

Asthma and obesity tend to co-occur, but relatively few studies have linked obesity, measured using body mass index (BMI), to clinically relevant measures of asthma morbidity. This study assessed BMI in a Canadian sample of asthma outpatients, and evaluated associations between BMI and levels of asthma severity, asthma control, and asthma-related quality of life. A total of 382 adult asthma patients underwent demographic and medical history interviews on the day of their clinic visit. Patients' self-reported height and weight were used to calculate BMI (kg/m(2)). Asthma severity was classified according the GINA (2002) guidelines. Patients completed the Asthma Control (ACQ) and Asthma Quality of Life (AQLQ) Questionnaires and underwent standard pulmonary testing (spirometry). A total of 139 (36%) patients had a normal BMI; 149 (39%) patients were overweight; and 94 (25%) patients were obese. There was no relationship between BMI and asthma severity when controlling for age and sex. Patients with higher BMI scores had higher ACQ and lower AQLQ scores, independent of age, sex and asthma severity. Results identify higher BMI and obesity as potential behavioral factors related to worse asthma control and quality of life, but not asthma severity, and suggest important avenues for asthma management and control initiatives.

Adult↗

PubMed2005

Are psychiatric disorders associated with worse asthma control and quality of life in asthma patients?

BACKGROUND: Achieving good asthma control has become the major goal of asthma treatment. Studies have reported a high rate of psychiatric disorders among asthma patients, though the impact of these disorders on asthma control and quality of life remains unexplored. This study evaluated the prevalence of psychiatric disorders in 406 adult asthma patients, and associations between psychiatric status, levels of asthma control, and asthma-related quality of life. METHODS: Consecutive asthma patients presenting to the asthma clinic underwent a brief, structured psychiatric interview, completed the Asthma Control Questionnaire (ACQ) and Asthma Quality of Life Questionnaire (AQLQ), and reported the frequency of bronchodilator use in the past week. All patients underwent standard pulmonary function testing. RESULTS: A total of 34% (n=136) of patients had one or more psychiatric diagnosis, including major depression (15%), minor depression (5%), dysthymia (4%), panic disorder (12%), generalized anxiety disorder (5%), and social phobia (4%). Though there were no differences in pulmonary function, patients with versus without psychiatric disorders had worse ACQ and AQLQ scores and reported greater bronchodilator use, independent age, sex and asthma severity. CONCLUSIONS: Results suggest that psychiatric disorders are prevalent among asthmatics and are associated with worse asthma control and quality of life. Physicians should be aware of the potential risk of poorer asthma control and functional impairment in this population.

Adult↗

PubMed2005

Airflow and autonomic responses to stress and relaxation in asthma: the impact of stressor type.

The impact of stress on respiratory airflow in asthmatics is unclear. Part of the uncertainty may spring from the different physiological effects of different stressors. Given their potential to elicit increases in parasympathetic vagal activity, stressful situations that present few opportunities for coping (passive coping stressors) may be particularly problematic for people with asthma. Thirty-one adult asthmatics participated in a protocol including a widely used passive coping stressor (the cold pressor test), an active coping stressor (mental arithmetic), an interview about an upsetting asthma-related incident (viewed as a potential passive coping stressor given the exposure to unpleasant memories), and progressive muscle relaxation. Repeated measurements of airflow (via peak expiratory flow), vagal tone (via heart rate variability), and other variables were obtained. The cold pressor test, asthma interview and progressive muscle relaxation produced significant decreases in airflow compared to the baseline period. The cold pressor test and progressive muscle relaxation produced significant, complementary increases in vagal tone. These results suggest that passive coping stressors and other stimuli (e.g., certain forms of relaxation) that elicit increased vagal tone may be associated with poorer asthma control, a view consistent with a significant negative correlation between the participant's mean vagal tone response to the tasks and score on a measure of asthma self-efficacy.

Adult↗

PubMed2004

Mild reactions to blood donation predict a decreased likelihood of donor return.

A growing body of evidence suggests that episodes of fainting can deter volunteer blood donors from returning to donate in the future. In contrast, relatively little is known about the effect of significantly more common mild reactions (e.g., faintness, dizziness, lightheadedness) on donor retention. In the present study, 1052 volunteer blood donors completed a standardized measure of subjective physiological reactions immediately after blood donation (Blood Donation Reactions Inventory), and individual scores were used to predict repeat donation behavior during a one-year follow-up. Results of a logistic regression analysis indicated that higher scores on the Blood Donation Reactions Inventory were associated with a significantly lower likelihood of repeat donation, and that novice donors who scored highest on the scale were less than half as likely to have returned to donate in the following year. These findings suggest that the Blood Donation Reactions Inventory is an effective method of assessing reactions that predict donor non-return, and therefore may be a useful addition to future studies aimed at enhancing donor satisfaction and retention.

Adult↗

PubMed2003

Adolescent pain sensitivity is associated with cardiac autonomic function and blood pressure over 8 years.

Low pain sensitivity has been reported in hypertensive subjects as well in groups deemed to be at increased risk of development of the disorder. However, it is uncertain whether individual differences in pain sensitivity are associated prospectively with increases in blood pressure. In the current study, 24-hour blood pressure and heart rate variability were recorded in 110, 22-year-old men previously assessed at age 14 years for casual blood pressure and pain sensitivity (mechanical finger pressure). Significant correlations were observed between pain tolerance in 14-year-olds and current 24-hour systolic blood pressure (r=0.37, P<0.01) and diastolic blood pressure (r=0.36, P<0.01). Hierarchical multiple regression analyses indicated that information regarding pain tolerance improved prediction of systolic and diastolic blood pressure at age 22 years beyond that afforded by differences in blood pressure, parental history of hypertension, and body mass index at age 14 years. Similar analyses revealed that average pain sensitivity at age 14 was also associated with 24-hour high-frequency heart rate variability (r=0.28, P<0.01) and low-frequency/high-frequency heart rate variability at age 22 (r=-0.35, P<0.01), suggesting increased sympathetic and reduced parasympathetic tone among individuals less sensitive to pain. These results provide further evidence that blood pressure related hypoalgesia might be related to processes involved in blood pressure regulation as well as in the development of sustained high blood pressure.

Adolescent↗

PubMed2003

Sweet taste and blood pressure-related analgesia.

To test the prediction that sweet taste modifies responses to cold induced pain, 72 young adults held sweet, bitter and water solutions in their mouths, in counterbalanced order, before and during a cold pain stimulus. To test whether or not blood pressure interacts with sweet taste analgesia, measurements of resting blood pressure were also obtained. A significant main effect of taste on pain tolerance was observed, as well as a significant interaction between resting mean arterial pressure (MAP) and taste on tolerance. Sweet taste was associated with a prolongation of tolerance compared to the bitter and water conditions. When participants were split along the median for MAP, sweet taste was associated with an 18.1% increase in pain tolerance compared with water for those with lower MAP. No significant impact of taste on pain sensitivity was observed among participants with higher MAP. Groupwise comparisons revealed a significant difference in pain tolerance between participants with higher and lower MAP in the water condition but not in the sweet condition, replicating previous findings of a reduced sensitivity to pain among those with higher blood pressure. The analgesic effects of sweet tasting solutions seen previously in human infants and children may also be present in adults. Individuals with higher blood pressure may not be as sensitive to the presumably opioid-mediated analgesic effects of sweet taste, perhaps due to opioid dysregulation.

Adult↗

PubMed2003

On-site training in applied muscle tension to reduce vasovagal reactions to blood donation.

Vasovagal reactions significantly complicate the blood collection process and, more importantly, discourage people who might otherwise donate blood many times from returning. Applied muscle tension is a simple behavioral technique that may reduce vasovagal reactions by maintaining blood pressure. It has been successfully used to treat patients with blood and injury phobias, but has not been applied in the more general, time-limited context of blood collection clinics. Thirty-seven inexperienced blood donors (maximum number of prior donations = 2) attending mobile blood collection clinics were asked to practice applied tension after watching a 2-min instructional video presented on a notebook computer. They were compared with 94 untreated donors with similar donation experience and 47 more experienced blood donors. Treatment reduced the number of symptoms reported on a postdonation questionnaire. It also significantly reduced the amount of medical treatment required (chair reclining) among those who practiced applied tension for the entire period they were in the donation chair.

Adult↗

PubMed2003

Reducing reactions to blood donation with applied muscle tension: a randomized controlled trial.

BACKGROUND: Unpleasant blood donation-related symptoms may discourage otherwise healthy, altruistic individuals from becoming repeat donors. This study examined a behavioral technique called applied muscle tension (AMT) that might reduce reactions. STUDY DESIGN AND METHODS: A total of 605 donors at mobile clinics were assigned to either an AMT treatment condition, a no-treatment control condition, or a placebo control condition. AMT involves repeated tensing of major muscles and was taught using an instructional video. Participants in the placebo control group watched the same video but were told to practice the technique only from the time they got on the donation chair until insertion of the needle, without being told that reactions are unlikely during this period. RESULTS: There were no differences between men assigned to the three conditions. Women donors assigned to the AMT condition reported significantly fewer donation-related symptoms, required less chair reclining for reactions, and were more likely to produce a full unit of blood than women in both the no-treatment and placebo control conditions. Women in the AMT condition also said they would be more likely to recommend it to a friend who was going to give blood, but there were no significant effects of AMT on the rated probability of giving blood again or blood pressure change. CONCLUSIONS: Although it was not universally effective and the mechanisms of its effects are unclear, AMT is a simple behavioral technique that may be useful in reducing reactions to blood donation.

Adult↗

PubMed2003

Familiality of heart rate and cardiac-related autonomic activity in five-month-old twins: the Québec newborn twins study.

The familiality of infant sleeping heart rate (HR) and cardiac-related autonomic activity, as indexed by spectral analysis of HR variability (HRV) and response to postural change, was investigated in 322 5-month-old twin pairs. The postural change elicited only minor changes in cardiovascular activity. As a result, analyses focused on supine cardiovascular activity. Multivariate genetic modeling indicated that individual differences in sleeping HR and high frequency (HF) HRV were determined by unique environmental and distinct additive genetic factors. These variables, along with low frequency (LF) HRV, were also affected by overlapping familial environmental influences. Familial influences in HF HRV were more pronounced for baby girls than boys. Estimates of relative LF and HF HRV were determined by common (familial) and unique environmental factors; familial influences on these estimates did not overlap with familial influences on sleeping HR.

Algorithms↗

PubMed2003

On reversible deafness, generalized anxiety disorder, and the motoric brain: a psychophysiological perspective.

Electromyographic (EMG) recording during presentation of loud sounds revealed central motor inhibition in a rare case of conversion disorder with deafness. Two subjects in whom hypnotic deafness was induced resembled the patient. In contrast, patients with generalized anxiety disorder (GAD) showed a significantly delayed return of EMG to baseline, compared with normals and schizophrenics following administration of auditory startle stimuli. Blood pressure (BP) of GAD patients was also slower to return to baseline than that of normals and schizophrenics. BP recorded continuously during seven consecutive tests revealed a striking difference between GAD patients and controls. While the controls' BP generally decreased during the session, pressure of the GAD patients remained at their initial levels. These data are interpreted in relation to allodynamic autonomic regulation as affected by vagal blockade, which appeared to decrease in controls while remaining undiminished in GAD patients. It is suggested that intrusions of uncontrollable worry in GAD patients, and their consequent overuse of certain rostral neural pathways involved in preparation for action prolonged their vagal blockade. A GAD case with typically high frontalis EMG is presented. Frontalis EMGs may provide an exceptionally sensitive indication of neural activity of relevance to GAD. EMG gradients in normal subjects draw attention to Sperry's motoric brain concept, whose influence is strong throughout the paper. Sperry's principle states that the main function of the brain is that of moving the animal in ways that are advantageous for satisfying basic needs and avoiding dangers. Also, with a focus on the motoric brain, some discoveries resulting from brain-recording experiments in freely moving rats are described.

Acoustic Stimulation↗

PubMed2002

Exaggeration of blood pressure-related hypoalgesia and reduction of blood pressure with low frequency transcutaneous electrical nerve stimulation.

Reduced pain perception has been observed in hypertensive individuals and normotensive individuals at risk for high blood pressure and may involve increased endogenous opioid release or receptor sensitivity. The present study examined the issue by administering two subjectively similar but physiologically different forms of the pain-reducing procedure transcutaneous electrical nerve stimulation (TENS). Men varying in resting blood pressure and parental history of hypertension participated in three testing sessions during which was presented (a) high-frequency (100 Hz) TENS; (b) low-frequency (2 Hz) TENS, the type believed to elicit endogenous opioid activity; or (c) no-TENS stimulation. Measurements of blood pressure (BP) and other physiological variables were obtained during this period. Afterwards, two pain stimuli were presented: a series of electric shocks and 5 min of arm ischemia. There was a significant negative association between pain and resting systolic blood pressure (SBP), and pain and parental history of hypertension in the no-TENS and high-frequency TENS conditions that was significantly strengthened by administration of low-frequency TENS. As well, low-frequency TENS produced a modest but significant acute reduction in SBP, especially among those with higher resting levels. These results provide further evidence that opioid mechanisms are involved in blood pressure-related hypoalgesia and blood pressure regulation.

Adult↗

PubMed2002

A longitudinal study of pain sensitivity and blood pressure in adolescent boys: results from a 5-year follow-up.

A growing literature has observed a significant reduction in pain sensitivity among hypertensive animals and humans. It is uncertain whether a reduced sensitivity to pain can be observed in nonnotensive individuals who go on to develop high blood pressure. Blood pressure (BP) was reassessed in one hundred fifteen 19-year-old boys initially tested at age 14, when they were also presented with a pain stimulus (mechanical finger pressure). Hierarchical regression analyses indicated that information regarding pain tolerance improved prediction of changes in systolic and diastolic blood pressure beyond that afforded by differences in BP at age 14, parental history of hypertension, and body mass index. These analyses suggest that pain sensitivity may be associated with physiological processes involved in the development of sustained high blood pressure.

Adolescent↗