The Polar Vantage XL heart rate monitor provides an ambulatory, inexpensive method of continuously measuring heart rate. To examine the validity of the Polar monitor for measuring heart rate during resting periods and while engaging in two stressful tasks, 30 students participated in a 1-hour laboratory session. Heart rates were measured simultaneously using the Polar monitor and electrocardiography (ECG) during a hand grip exercise and a mental arithmetic task, each preceded by a 4-min resting period. Within-subject correlations between the two devices were significant (mean r = 0.98, P < .001). All correlations, except for three participants, exceeded r = 0.90. Between-task correlation analyses revealed high correlations (i. e., rs ≥ 0.98) between the Polar monitor and ECG. The Polar monitor obtained readings that were slightly, though significantly higher than readings obtained using ECG. The correspondence between observed mean heart rates from the Polar monitor and ECG suggest that the Polar monitor provides a valid measure of heart rate during stationary laboratory tasks.
Three functional assessment methods were conducted with four adults with severe to profound mental retardation who exhibited stereotypic behavior. We compared the results of an informant assessment using the MAS, an A-B-C direct observation assessment, and a functional analysis in which variables were manipulated in four experimental conditions. The results of the A-B-C observations and the MAS indicated a sensory function of the stereotypic behavior for all subjects. The functional analysis results were more ambiguous, with a different pattern of results for each subject. These results are discussed with regard to the practicality and utility of each functional assessment procedure conducted in an applied setting.
To examine the utility of blood pressure (BP) habituation within and across multiple clinic visits and patientdetermined home BP monitoring for detecting white coat (WCE) and reverse white coat effects (RWCE) commonly observed in medical settings, 54 patients undergoing evaluation for hypertension in an internal medicine group practice were categorized according to the magnitude of differences between systolic BP (SBP) and diastolic BP (DBP) obtained in the clinic and through ambulatory BP monitoring. BPs were measured four times during three separate clinic visits, during a 1-week home BP monitoring period, and during a single 24-h ambulatory monitoring period. Patients whose mean clinic and average daytime BPs were within 75 mm Hg were categorized as having stable BP; patients whose clinic BPs were 45 mm Hg of their daytime BPs were categorized as showing a WCE and patients whose average daytime BPs were 45 mm Hg of their clinic BPs were categorized as showing a RWCE. Results revealed that degree of habituation occurring between the first and third clinic visits significantly predicted magnitude of both the WCE and RWCE for SBP, with greater habituation being associated with the WCE and lesser habituation associated with the RWCE. Greater SBP habituation within clinic visits was associated with the WCE for SBP and greater DBP habituation within clinic visits was associated with the WCE for DBP. Lesser DBP habituation within clinic visits was associated with the RWCE for both SBP and DBP. Home BP monitoring did not contribute to predicting either WCE or RWCE.
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