Self-monitoring cognitive performance during sleep deprivation: effects of modafinil,d-amphetamine and placebo

Self-monitoring refers to the ability to assess accurately one's own performance in a specific environment. The present study investigated the effects of the stimulating drugs modafinil (300 mg) and d-amphetamine (20 mg) on the ability to self-monitor cognitive performance during 64 h of sleep deprivation (SD) and sustained mental work. Two cognitive tasks were investigated: a visual (perceptual) judgment task and a complex mental addition task. Subjects in the placebo condition displayed marked circadian and SD effects on cognitive task performance but their self-monitoring was substantively undisturbed by SD. Subjects performing under the influence of d-amphetamine likewise displayed highly proficient self-monitoring throughout the SD period. In contrast, modafinil had a disruptive effect on self-monitoring, inducing a reliable «overconfidence» effect (i.e. an overestimation of actual cognitive performance), which was particularly marked 2–4 h post-dose. Although modafinil has proven to be a safe and effective countermeasure to the effects of extensive SD on cognitive task performance, we encourage a more comprehensive understanding of the relation between its subjective and performance enhancing effects before the drug is recommended as a viable fatigue countermeasure.     

Effectiveness of a Self-Monitoring Quality of Life Intervention For Patients with Cancer Receiving Palliative Care: A Randomized Controlled Clinical Trial

Background: Use of patient-reported outcome measures in routine clinical practice has important benefits forpatients with cancer. To examine the effect of a self-monitoring quality of life (QOL) intervention on global QOL andphysical and emotional function in patients with cancer receiving palliative care. Methods: Prospective randomizedstudy had been undertaken at Toshima Hospital, Japan. This study compared an intervention group that completed theshortened Care Notebook booklet versus a control group that received usual care. The primary outcome was global QOLand secondary outcomes were physical and emotional function. Participants completed the European Organization forResearch and Treatment of Cancer Quality of Life Questionnaire Core 15 Palliative at baseline, and at 1 and 3 weeks.The effects of the intervention were evaluated with a linear mixed-effects model. Results: Forty-three patients wererandomized. One patient in each group could not receive the allocated intervention, leaving 41 patients for inclusionin the modified intention-to-treat (ITT) analysis for the primary outcome. Twenty-seven patients were analyzed for thesecondary outcomes using per protocol set (PPS). The ITT analysis showed no significant overall effect on global QOL(P=0.285), but the PPS analysis showed a significant overall effect on global QOL (P=0.034) and physical function(P=0.047) for group difference over time in the linear mixed-effects model. Conclusions: Use of the Care Notebookmight have beneficial effects. The results could be interpreted as the effectiveness of the intervention of the CareNotebook for with cancer receiving palliative care.     

Blood glucose monitoring by children at home: A comparison of methods

Abstract The accuracy of measurements of blood glucose performed at home by the index children and/or parents was compared using the Boehringer Mannheim reagent strips, Ames Visidex-2 strips, an Ames Glucometer and a Boehringer Mannheim Reflolux reflectance meter.
Capillary plasma samples, collected simultaneously, were later analysed by a Beckman glucose oxidase analyser. The coefficent of correlation between the self-monitored results (SMR) and the laboratory-analysed results (LAR) ranged from 0.59 to 0.92, the composite being 0.74. The mean difference between the SMR and the LAR was 1.0 mmol/l.
The occurrence of potential errors of management due to incorrect SMR results was determined. On four occasions, the SMR was greater than 6 mmol/l when the LAR was less than 3 mmol/l, and on 36 occasions a discrepancy greater than 50% occurred between the two values, without resulting hypoglycaemia.     

The ability to self-monitor performance when fatigued

The present study aimed to systematically investigate the effects of elevated fatigue levels on the ability to self-monitor performance. Eighteen participants, aged 19-26 y, remained awake for a period of 28 h. Neurobehavioural performance was measured at hourly intervals using four tests from a standardized computer test battery. From these four tests, six measures of performance were obtained: grammatical reasoning (accuracy and response latency); vigilance (accuracy and response latency); simple sensory comparison and tracking. In addition, before and after each test, participants completed visual analogue scales which required them to rate their alertness level and the speed and accuracy of their performance. Individual test results for both self-ratings and neurobehavioural performance were converted to z-scores. Planned comparison analysis indicated that scores on four of the six performance measures decreased significantly as hours of wakefulness increased. Similarly, predicted performance scores for all six measures of performance decreased significantly. Analysis revealed moderate correlations between predicted and actual performance for the four parameters affected by fatigue. Furthermore, moderate to high correlations were found between all six performance parameters and their respective post-test self-ratings. In addition, moderate to high correlations were found between predicted performance and alertness. Taken together, these findings suggest that as fatigue levels increase, subjects globally assess performance decrements. Results suggest that subjective alertness may in part mediate an individual's global assessment of performance.     

Accuracy of the CONTOUR® blood glucose monitoring system

Objective

The aim of the study was to assess the accuracy of the CONTOUR® blood glucose monitoring system (BGMS) according to the International Organization for Standardization''s International Standard 15197 (ISO 15197:2003) guidelines and to more stringent criteria.

Method

Finger stick blood samples from 105 subjects with diabetes (25 with type 1, 77 with type 2, and 3 with type unknown) were tested using the CONTOUR BGMS and YSI glucose analyzer.

Results

99.3% of results were within ISO 15197:2003 criteria (±15 mg/dl of YSI results at glucose concentrations <75 mg/dl and ±20% at glucose concentrations ≥75 mg/dl). Additionally, 96.7% of results were accurate according to more stringent criteria (±15 mg/dl of YSI results for glucose concentrations <100 mg/dl and ±15% for glucose concentrations ≥100 mg/dl). Error grid analysis showed that 99.3% and 0.7% of results were within zones A and B, respectively.

Conclusion

The CONTOUR BGMS exceeded both the minimum acceptable accuracy based on ISO 15197:2003 and the more stringent accuracy criteria.     

Hematocrit compensation in electrochemical blood glucose monitoring systems

Background

Hematocrit (Hct) is a common interferent in test strips used by diabetes patients to self-monitor blood glucose (BG), resulting in measurement bias. Described is an electrochemical BG monitoring system (OneTouch^® Verio™) that uses a cofacial sensor design, soluble enzyme chemistry, and multiphasic waveform to effectively correct for patient Hct, delivering an accurate reading for whole BG.

Methods

The test strip comprises thin-film gold and palladium electrodes arranged cofacially and spatially separated with a thin spacer. Soluble glucose-sensing reagents are located on the lower palladium electrode and are hydrated on sample application. Blood glucose is oxidized by flavoprotein glucose dehydrogenase, with electron transfer via (reduced) potassium ferrocyanide mediator at the palladium electrode. Hematocrit levels are estimated by measuring oxidation of mediator diffusion to the upper gold electrode during the first portion of the assay. The Hct-corrected glucose levels are determined by an on-meter algorithm.

Results

In performance testing of blood samples at five glucose levels (30–560 mg/dl) and five Hct levels (19–61%), using 12 test meters and 3 test strip lots, 100% of results (N = 2700) met International Organization for Standardization accuracy criteria (within ± 15 mg/dl and ± 20% of reference results at glucose levels of <75 and ≥75 mg/dl, respectively). Furthermore, 99.9% (2698 of 2700) of results were within ±12 mg/dl and ± 15% of reference values at glucose levels <80 and ≥80 mg/dl, respectively.

Conclusions

The technology used in this system provides accurate BG measurements that are insensitive to Hct levels across the range 20–60%.     

Analysis Article on the Performance Analysis of the OneTouch? UltraVue? Blood Glucose Monitoring System

In this issue of Journal of Diabetes Science and Technology, Chang and colleagues present the analytical performance evaluation of the OneTouch® UltraVue™ blood glucose meter. This device is an advanced construction with a color display, used-strip ejector, no-button interface, and short assay time. Accuracy studies were performed using a YSI 2300 analyzer, considered the reference. Altogether, 349 pairs of results covering a wide range of blood glucose concentrations were analyzed. Patients with diabetes performed a significant part of the tests. Obtained results indicate good accuracy of OneTouch UltraVue blood glucose monitoring system, satisfying the International Organization for Standardization recommendations and thereby locating >95% of tests within zone A of the error grid. Results of the precision studies indicate good reproducibility of measurements. In conclusion, the evaluation of the OneTouch UltraVue meter revealed good analytical performance together with convenient handling useful for self-monitoring of blood glucose performed by elderly diabetes patients.     

New Approaches to Display of Self-Monitoring of Blood Glucose Data

Background

There is a need for improved methods for display and analysis of self-monitoring of blood glucose (SMBG) data to facilitate identification of clinical problems, assist the clinician in the interpretation of daily patterns and longitudinal trends, serve as a guide to locating the most important segments of logbook data, and permit rapid analysis of the patient''s pattern of glucose monitoring.

Methods

We developed prototype software to display SMBG data in a two-dimensional color-coded array: Time of day is displayed on the horizontal axis; date or sequential day is displayed on the vertical axis. Each glucose value is shown by a color-coded symbol categorizing it as “very high,” “high,” “within target range,” “low,” or “very low.” The number of categories and their ranges can be defined by the user, and different target ranges and limits for the categories can be used for different times of day. Placing the cursor over any observation activates a “pop-up box” showing the date, day of week, time of day, glucose value, and ancillary information. Several options and variations are available.

Results

This new type of display is compact, serves as a guide to assist the physician in locating the most important segments of the logbook, and permits display of glucose data from 90 or more days in a chart as small as 4 by 4 inches. This analysis permits rapid identification of measurements that are above or below the target range and facilitates rapid evaluation of patterns observed on different days or days of the week.

Conclusion

These new approaches complement other popular graphical displays by conveying information efficiently and effectively to the physician, other health care providers, the patient, and family caregivers in a new and novel, concise, standardized yet flexible format.