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Biomedical subjects

W Linden

Publications and source records attributed to W Linden.

At least 37 records · Page 2Linked to original sources
PubMed1994

Laboratory reactivity models as predictors of ambulatory blood pressure and heart rate.

We attempted to validate the usefulness of the laboratory reactivity paradigm by examining responses to three distinct lab tasks and an overall lab average as predictors for ambulatory blood pressure. Subjects were 126 university students. We assessed ambulatory blood pressure, heart rate and perceived distress during an 8-hr working day. In the lab, all subjects responded to three standardized 5-min tasks: isometric handgrip, mental arithmetic, and a structured discussion of a recent interpersonal conflict situation. The analyses used absolute task levels, change scores, a composite index of reactivity, and a mean value for all obtained lab measures. Task levels correlated significantly with means of the ambulatory cardiovascular indices; the scores ranged from 0.35 to 0.49 for SBP, from 0.45 to 0.58 for DBP, and from 0.57 to 0.65 for HR. Only the DBP change score associated with the discussion task correlated with the ambulatory mean. The correlations between lab task levels and ambulatory measures were strongest for the discussion task and the composite score; the task level for the math task was consistently the weakest predictor of ambulatory activity. When lab resting values were forced into a step-wise multiple regression as step one, only the response to the discussion added significantly (3% each for SBP and DBP) to the variance in ambulatory pressure that was not already explained by resting values. The overall lab mean for SBP was a better predictor of the ambulatory mean than was any combination of resting values and reactivity indices.

Adolescent↗
PubMed1993

Relative importance of psychologic traits and severity of ischemia in causing angina during treadmill exercise. Canadian Amlodipine/Atenolol in Silent Ischemia Study (CASIS) Investigators.

OBJECTIVES: This study was conducted to compare the influence of psychologic traits versus ischemia severity on the occurrence of angina during treadmill exercise. BACKGROUND: Some studies suggest that angina is associated with certain psychologic traits, whereas others show an association with more severe ischemia. The relative influence of these two factors and the extent to which they interact are not known. METHODS: Off-drug treadmill exercise testing and a battery of psychologic tests were performed on 122 patients with known coronary artery disease. Psychologic tests measured sensitivity to physical symptoms, denial and deception, type A behavior, anger, hostility, depression, marital adjustment and amount of external stress. Stepwise logistic regression was used to determine the independent association of psychologic traits, ischemic threshold and exercise tolerance with the occurrence of angina. RESULTS: Angina during treadmill exercise was reported by 66 of 122 patients. On univariate testing, angina was positively associated with sensitivity to physical symptoms (p < 0.001), type A behavior (p = 0.021) and depression (p = 0.032) and was negatively associated with exercise tolerance (p < 0.001) and work load threshold for ischemia (p < 0.01). Multivariate analysis revealed independent and additive associations of angina with sensitivity to physical symptoms (p = 0.003), exercise capacity (p = 0.003) and work load threshold for ischemia (p = 0.018). Once these were included in a logistic model, depression and type A behavior were no longer significant. Other psychologic traits showed no association with angina. CONCLUSIONS: Sensitivity to physical symptoms, ischemic threshold and exercise tolerance are independently associated with angina, with sensitivity to physical symptoms having the stronger influence. The physiologic and psychologic mechanisms underlying symptom perception have an influence on angina that is independent of and additive to the severity of underlying ischemia.

Amlodipine↗
PubMed1993

Sex differences in social support, self-deception, hostility, and ambulatory cardiovascular activity.

The quality of the social network, ambulatory cardiovascular indices, and other health risks were assessed in 129 students. Ss carried an ambulatory monitor for a working day and completed a social support scale, an index of daily stress, and measures of anger expression, hostility, depression, and self-deception. Alcohol intake and skinfold thickness were assessed. Results indicated that quality of social support was related in an inverse manner to ambulatory systolic pressure in women only. Stepwise multiple regression confirmed that social support was an independent predictor of daily systolic pressure for women and was not confounded with subjective stress. For men, tendencies to self-deception and high hostility were independently related to elevated blood pressure and heart rate.

Adolescent↗
PubMed1992

A psychophysiological evaluation of female urethral syndrome: evidence for a muscular abnormality.

This is a preliminary investigation into a recently defined urological disorder occurring in a subgroup of women with "urethral syndrome" suggestive of pelvic floor muscular (PFM) dysfunction. Symptoms include straining to void, urgency, frequency, hesitation, incontinence and/or retention, and subpubic pain. Finding neither bladder nor urological abnormalities, urologists may consider these women emotionally unstable without organic cause for their symptoms. However, their distress may be a consequence rather than a cause of their voiding problems. Sixteen female urological patients were matched with 16 asymptomatic controls to investigate PFM functioning, psychological status, and symptomatology. Results showed heterogeneity of symptomatology and little elevation of depression or anxiety when comparing patients with controls. Hypotheses of muscular abnormality were confirmed. Patients evidence poor control over testing and relaxing PFM, elevations of PFM activity under various conditions, and chronic pain as a prominent symptom. Treatment approaches specifically designed to address PFM dysfunction are discussed.

Adult↗
PubMed1992

Family history of hypertension and cardiovascular changes during high and low affect provocation.

The present study investigated whether subjects with a positive family history of hypertension would display differential responses in blood pressure and heart rate across different laboratory tasks. We also wanted to know whether subjects would display stable within-subject responses across different laboratory tasks. Twenty-three family history positive subjects and 23 with a negative family history participated in three tasks: 1) mental arithmetic, 2) a conversation about the weather (low affect task), and 3) a conversation about a recent upsetting, interpersonal event (high affect task). Positive family history was associated with elevated diastolic resting blood pressure and greater diastolic responsivity overall. For both groups, arithmetic was associated with the greatest heart rate changes, whereas the distressing conversation was accompanied by the greatest diastolic blood pressure response. Stability of cardiovascular activation across different tasks was present only for heart rate; it was weak for diastolic blood pressure, and completely absent for systolic blood pressure.

Adult↗
PubMed1991

Is response adaptation a threat to the high-low reactor distinction among female college students?

Examined cardiovascular-response adaptation patterns in high- versus low-cardioreactive women. Responses to a mental-arithmetic-plus-noise task were compared within trials (3 min each), across trials (three per session), and across two sessions separated by a 4-week interval. Forty-four normotensive women (mean age = 22.5 years) completed the study. Heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were monitored. Analyses of variance were employed to analyze the repeated-measures design and indicated consistent decreases in HR, SBP, and DBP response magnitudes across visits, trials, and minutes. Decreases in HR were greatest from Minute 1 to Minute 2 within each trial and, similarly, from Trial 1 to Trial 2 within each visit. BP responses showed a delayed onset of within-trial adaptation. Reactivity groups were formed for (a) SBP reactivity for HR and DBP analyses and (b) HR reactivity for SBP analyses. Although high reactors (top tercile) showed greater adaptation to task repetition in all responses compared to low reactors (lowest tercile), they also consistently displayed greater responses. Even during the final task, SBP and HR responses discriminated between high and low reactors.

Adolescent↗
PubMed1991

What do arithmetic stress tests measure? Protocol variations and cardiovascular responses.

Three studies tested the effects of the following design/protocol variations in mental arithmetic: 1) Order of task, 2) vocal versus written delivery of responses, 3) effects of different types of superimposed noise distractors, and 4) varying types of mental arithmetic challenges. All studies used the same basic protocol with 20-min adaptation, 5-min task, and 3-min recovery periods; dependent cardiovascular variables were systolic and diastolic blood pressure and heart rate; in Study 2 respiration rate and respiratory amplitude were also assessed. Findings showed that vocal delivery enhanced subjective distress, lowered performance, and enhanced diastolic blood pressure responses. Noise distraction augmented distress but did not affect task performance. Variable noise distraction augmented systolic blood pressure and heart rate responses but only when math equations were presented on a video screen. Autonomic response adaptation was apparent from first to second tasks but not thereafter. The built-in replications strengthened these findings.

Adult↗
PubMed1989

Should we tell them when their blood pressure is up?

We carried out two studies to determine the effects of feedback on subsequent blood pressure and heart rate readings in subjects without significant cardiovascular abnormalities. In both studies the subjects were randomly assigned to be told that their blood pressure was normal or was high or to receive no feedback at all; 3 minutes later another reading was taken and correct feedback provided. Study 1 was done in 114 patients who attended a family practice teaching unit for an office visit; subjects taking cardioactive medication or with chronically elevated blood pressure (diastolic pressure more than 95 mm Hg) or known low pressure (diastolic pressure less than 60 mm Hg) were excluded. Half of the subjects received feedback from a nurse and the other half from a physician. We found no effect of type of feedback or type of practitioner on subsequent readings. No adaptation of diastolic blood pressure or heart rate took place, whereas a similar rest period in the laboratory consistently triggers cardiovascular adaptation. Given the field nature of the study it was not clear whether the intervention was not powerful or whether the practitioner-patient interactions diffused the effects of an otherwise powerful intervention. Therefore, a second study with the same design was carried out in a controlled laboratory setting with 61 university students who believed they were in the adaptation phase of an experimental stress protocol. The subjects did not interact with the experimenter, who provided only the initial feedback, via intercom. The findings replicated those of study 1: type of feedback had no significant effect on subsequent blood pressure levels, and all types of feedback prevented cardiovascular adaptation. We recommend that patients be allowed to rest alone for at least 10 minutes before blood pressure is measured. Our findings suggest that practitioners need not be concerned about telling normotensive or borderline hypertensive patients that their blood pressure is elevated.

Adult↗
PubMed1988

Expectancy and type of activity: effects on pre-stress cardiovascular adaptation.

This study evaluated the effects of expectancy and type of activity on cardiovascular change during a 20 min pre-stress adaptation period. Subjects (N = 115) were randomly assigned to six conditions with three differing types of activity and two different instructions for expectancies. The three activities were (a) resting quietly, (b) reading neutral, entertaining material (i.e., Herman cartoons), or (c) reading stress-relevant questionnaires. Subjects were told to either expect or not expect to participate in a subsequent stress study. The findings clearly indicated that (1) neither the expectancy nor the activity manipulations had significant impact on autonomic resting values at the end of 20 min of adaptation, but (2) subjects consistently reported increased feelings of relaxation and noted differential mood change in the cartoon relative to the stress questionnaire condition. Furthermore, the study revealed that instructions to read stress questionnaires initially delayed heart rate adaptation when contrasted with the resting and cartoon conditions. Implications of these findings for a more comprehensive understanding of the pre-stress adaptation phenomenon are discussed.

Adaptation, Physiological↗
PubMed1987

Repression, hostility, and autonomic recovery from a laboratory stressor.

The current study investigated hostile mood, response style (repression-sensitization [RS]), and cardiovascular (blood pressure and heart rate) as well as endocrine recovery (cortisol, norepinephrine, and epinephrine) from a 10-minute mental task in 57 healthy, adult women. Emphasis was placed on resting levels and recovery from, rather than the more frequently studied initial responses to, mental stress tasks. The task consisted of the "Electrocardiogram Quiz" (shortened version) and mental arithmetic (serial subtraction) of equal length, totaling 10 minutes. Physiological/biochemical samples were collected at the end of a 15-minute adaptation phase (i.e., the designated baseline), at the end of the mental task phase and at 5-minute and 30-minute recovery. R-S and hostility scale scores were not correlated and permitted the creation of four subsamples: 1) repressor-low expressed hostility; 2) repressor-high expressed hostility; 3) sensitizer-low expressed hostility; and 4) sensitizer-high expressed hostility. Results indicated that tonic levels of SBP and DBP were consistently higher in subjects with low expressed hostility. Cortisol level and phasic activity discriminated between high expressed hostility-sensitizers and the other three samples, with the former displaying more cortisol activity at baseline and at 30-minute recovery. Women on birth control pills had consistently elevated levels of cortisol secretion throughout.

Adolescent↗
PubMed1986

Lack of comparability of two automated blood pressure monitors in a hypertensive population.

Two frequently used automated, blood pressure monitors, the Arteriosonde and the Dinamap, were compared with each other and with a standard mercury sphygmomanometer. Fifteen patients with elevated blood pressure were studied: 5 were untreated, 5 received a diuretic alone, and 5 received a beta blocker alone. One hundred and twenty blood pressure measurements were taken from each subject with two different instruments (one on each arm) in a 2 (supine or standing position) X 2 (left or right arm) X 3 (three different sets of pairwise instrument comparisons) X 5 (five one-minute interval measurements per phase) factorial design. A reasonable inter-instrument comparability for systolic blood pressure was found with mean deviations of +1.3 mmHg and -3.8 mmHg from the mercury sphygmomanometer for the Dinamap and Arteriosonde, respectively. Differences between instruments for diastolic pressure however, were significantly larger. The Arteriosonde systematically obtained higher diastolic pressure values (+7.4 mmHg) than the mercury sphygmomanometer or the Dinamap (10.7 mmHg). Diastolic pressure on the Dinamap was on average 5.2 mmHg lower than on the mercury sphygmomanometer. Left/right arm differences and differences for the treatment conditions were not observed. Findings clearly suggest that these two automated blood pressure monitors cannot be used interchangeably with each other or with the mercury sphygmomanometer in either a research or clinical setting. Overall the Dinamap approached mercury sphygmomanometer measures more closely than did the Arteriosonde.

Adrenergic beta-Antagonists↗
PubMed1985

Cardiovascular response as a function of predisposition, coping behavior and stimulus type.

The present study investigated cardiovascular responses to three different laboratory stressors in either low or high heart rate reactors. It was predicted that there would be stimulus specific responses for either a mild pressure pain, mental arithmetic, or projective test stimulus. Mild pain was to reflect a passive coping condition, and mental arithmetic an active one while the projective test was to represent an ambiguous stimulus condition permitting idiosyncratic behavioral responding. Blood pressure and heart rate responses revealed the predicted small response to mild pressure pain and the predicted stress response to mental arithmetic. Low and high heart rate reactors did not differ in response to mild pain or the projective task but differed greatly in response to the arithmetic task. The data further indicated that low heart rate reactors responded with a larger response in blood pressure and heart rate to the projective test than to the mental arithmetic, whereas the high heart rate reactors displayed an inverse pattern. Psychological trait or situational, behavioral variables failed to predict the physiological response.

Adult↗
PubMed1985

A review of physiological prestress adaptation: effects of duration and context.

This review focuses on 3 aspects of experimental designs for prestress, physiological adaptation periods: (1) effects of duration on stabilization of various physiological parameters:(2) effect of type of activity and instruction on prestress physiological adaptation: and (3) definitions of physiological baselines. Analyses of the literature revealed that for many physiological parameters it remains unclear how much time is required for stabilization and that for the remaining variables the necessary duration of prestress adaptation varies greatly, with blood pressure potentially being the slowest variable to stabilize. Effects of type of activity are essentially unknown. Instructions which create certainly about experimental procedures in subjects tend to facilitate adaptation to the laboratory environment. Baseline definitions were remarkably variable with no less than 15 different definitions being used across the 50 studies reviewed. Suggestions for future research and recommendations for prestress experimental designs are put forward in the discussion.

Adaptation, Physiological↗
PubMed1985

The effect of noise interference, type of cognitive stressor, and order of task on cardiovascular activity.

In the search for reliable, easily applicable mental stressors many researchers have investigated the propensity of mental arithmetic and Stroop color discrimination tasks to elicit a physiological stress response; some researchers have added noise interference with the expectation of larger response magnitudes. The present study investigates a number of previously untested questions by directly comparing cardiovascular responses to mental arithmetic or the Stroop task with and without noise interference in a sample of 66 young adults. Half of all subjects were exposed to the additional noise interference, all subjects responded to both types of mental stressors. Blood pressure responses did not discriminate among the stressors but noise interference consistently augmented heart rate responses during mental arithmetic. Response to the second, repeated stressor was associated with highly significant response habituation effects for blood pressure. Furthermore, when mental arithmetic was presented first, both tasks elicited comparable and large responses; when the Stroop test was presented first both tasks triggered smaller responses but of comparable magnitude. Subjective evaluations of the stressors were not predictive of overall physiological response.

Adult↗
PubMed1984

Comparative accuracy of two new electronic devices for the noninvasive determination of blood pressure.

Recent developments in behavioral approaches to cardiovascular disease have called for physiological monitoring devices that reduce experimenter bias, are easy to operate, can be used ambulatorily, and/or provide ongoing, automated monitoring of pertinent cardiovascular functions--i.e., blood pressure and heart rate. Neither the invasive monitoring (via catheterization) nor the standard auscultatory method of blood pressure determination, however, has these characteristics. In the present study, two new methods/devices--(1) a low-weight, low-cost, battery-operated sphygmomanometer (SM), and (2) a more expensive automated electronic SM with electrical pump-are compared with each other and with the more common auscultatory method and a standard mercury SM. Both new devices were also compared with a standard pulse count. Data were derived from 10 readings of 10 healthy subjects each across the three possible comparisons, thus totaling N = 30. Correlation coefficients and average differences were computed and indicated high intercorrelations (between r = .89 and r = .99) between each pairing of the new electronic devices and the mercury SM. Intercorrelations of blood pressure determination with the two new electronic devices, however, were only moderate. Potential reasons for the variability are discussed, and guidelines for the optimal use of the new, easy-to-operate electronic devices are presented.

Adult↗