Blood glucose discrimination training in insulin-dependent diabetes mellitus (IDDM) patients

Self-management of insulin-dependent diabetes mellitus (IDDM) is dependent on a negative feedback loop of blood glucose (BG) fluctuations, which in turn directs treatment decisions to maintain normal BG. Although this feedback is typically accomplished by self-monitoring of blood glucose (SMBG), SMBG has limitations, and patients often rely on what their BG feels like. Two studies were performed to evaluate whether patients could learn to more accurately feel/discriminate their BG on the basis of internal cues or internal plus external BG cues. In Study I, BG Awareness Training significantly improved pre- to posttreatment BG estimation accuracy, relative to a control group. Study II replicated BG Awareness Training efficacy in improving BG estimation accuracy. Improvement in estimation accuracy was related only to initial accuracy; those who were initially less accurate improved the most. This improvement was represented in a 31% reduction in dangerous BG estimation errors and a 9% increase in accurate estimates. Resulting estimations were, however, still significantly less accurate than SMBG at the end of training.This research was supported by NIH grants AM282880, AM24177, AM22125, and RR00847 and by the Ames Company. The authors express their appreciation for the contribution made by trainers Leslie Butterfield and Linda Zimbelman, by the nursing staff at the University of Virginia's Clinical Research Center and the Diabetes and Nutrition Unit, and by Dr. James May from the Medical College of Virginia in soliciting subjects. We would also like to thank Andrea Snyder for her assistance.     

Accuracy of subjective blood glucose estimation by patients with insulin-dependent diabetes

A between-groups design using a baseline, treatment, follow-up procedure was used to investigate the accuracy of 20 patients with insulin-dependent diabetes when subjectively estimating their blood glucose levels. Patients were encouraged to attend to their mood for cues when making estimates of their blood glucose. Their capacity for reducing estimation errors when given immediate or delayed feedback of actual blood glucose was examined. The results showed that neither delayed nor immediate feedback produced a significant improvement in the mean estimation accuracy of these groups of patients or in their ability to predict whether their blood glucose was in the acceptable or unacceptable range. Patients were particularly inaccurate in detecting Low [less than 4.0 mmol/L (less than 72.0 mg/dl)] and Very High [greater than 16.0 mmol/L (greater than 288.0 mg/dl)] blood glucose levels. Examination of mood-blood glucose relationships revealed consistent patterns for individual subjects and considerable differences between subjects.     

Evaluating the Accuracy of Modern Glucose Meters

Background: Self-mmonitoring of blood glucose (SSMBG) is important for all patients with diabetes, as it provides valuable feedback on the effects of diet, exercise, and medications. To maximize the potential benefits of SMBG, clinicians must have confidence in the accuracy of their patients' glucose meters.Objective: The aim of this article is to review several issues related to glucose meter accuracy and ways that accuracy can be enhanced.Methods: A MeDLINE search of English-language articles using the terms SMBG, glucose meter,and accuracy as an initial screen was performed. After articles describing the use of outdated technologies or vague methodologies were excluded, appropriate articles that analyzed various aspects regarding meter accuracy were selected.Results: Glucose meter accuracy studies are complicated by issues related to the reference method, the sample being assayed, nd he ay n which accuracy s reported. error rid analysis ives linicians a means to valuate the clinical importance of meter error. Modern glucose meters have many technological improvements and enhanced clinical accuracy; however, the accuracy of readings depends not only on the instrument but also on patient technique and other aspects of the overall testing process.Conclusions: SMBG has proven to be a valuable tool for the management of diabetes whether it is used to guide insulin dosing, provide feedback on the effect of meals, or detect hypoglycemia. Accuracy of SMBG can be optimized by patient education and continued improvements in meter technology.     

Accuracy of subjective blood glucose estimation by patients with insulin-dependent diabetes

A between-groups design using a baseline, treatment, follow-up procedure was used to investigate the accuracy of 20 patients with insulin-dependent diabetes when subjectively estimating their blood glucose levels. Patients were encouraged to attend to their mood for cues when making estimates of their blood glucose. Their capacity for reducing estimation errors when given immediate or delayed feedback of actual blood glucose was examined. The results showed that neither delayed nor immediate feedback produced a significant improvement in the mean estimation accuracy of these groups of patients or in their ability to predict whether their blood glucose was in the acceptable or unacceptable range. Patients were particularly inaccurate in detecting Low [<4.0 mmol/L (<72.0 mg/dl)] and Very High [>16.0 mmol/L (>288.0 mg/dl)] blood glucose levels. Examination of moodblood glucose relationships revealed consistent patterns for individual subjects and considerable differences between subjects.The authors wish to thank the consultant physician Dr. J. D. Ward, and Drs. G. Knight and A. J. M. Boulton from the Royal Hallamshire Hospital, Sheffield, for referring the patients who took part in the study. The research was funded by NIH Grant number AM28196 to Dr. C. Bradley.     

Blood glucose discrimination training in patients with type II diabetes

This study was designed to determine whether patients with Type II diabetes could be taught to discriminate blood glucose after experiencing a variety of blood glucose levels and receiving feedback on the accuracy of their estimates. Thirty-six subjects (18 on oral agents and 18 on insulin) were randomly assigned to one of two feedback conditions: (1) current feedback, which received accurate information regarding their blood glucose levels, (2) noncurrent feedback, which received blood glucose levels from the preceding session. Subjects were exposed to a wide range of blood glucose values in six training sessions by ingesting drinks with three different caloric loads. In pre/post comparisons using several indices of accuracy, both groups showed significant improvement in estimating blood glucose levels. However, feedback on current blood glucose levels did not produce greater improvement than noncurrent. Accuracy was unrelated to the degree to which subjects reported associating internal sensations to their estimates. Failure to find differences between the two feedback conditions may have been due to the noncurrent feedback group's receiving fairly accurate information, to the difficulty of the discrimination task, and to the limited number of training trials.     

Blood glucose discrimination training in patients with Type II diabetes

This study was designed to determine whether patients with Type II diabetes could be taught to discriminate blood glucose after experiencing a variety of blood glucose levels and receiving feedback on the accuracy of their estimates. Thirty-six subjects (18 on oral agents and 18 on insulin) were randomly assigned to one of two feedback conditions: (1) current feedback, which received accurate information regarding their blood glucose levels, (2) noncurrent feedback, which received blood glucose levels from the preceding session. Subjects were exposed to a wide range of blood glucose values in six training sessions by ingesting drinks with three different caloric loads. In pre/post comparisons using several indices of accuracy, both groups showed significant improvement in estimating blood glucose levels. However, feedback on current blood glucose levels did not produce greater improvement than noncurrent. Accuracy was unrelated to the degree to which subjects reported associating internal sensations to their estimates. Failure to find differences between the two feedback conditions may have been due to the noncurrent feedback group's receiving fairly accurate information, to the difficulty of the discrimination task, and to the limited number of training trials.The authors thank Marsha D. Marcus, Ph.D., for her contributions to this study.     

Relationship between diurnal glucose levels and HbA1c in type 2 diabetes.

AIMS AND METHODS: Study results still conflict on the contribution of diurnal blood glucose (BG) values to Hb (A1c) in type 2 diabetes. We investigated the relationship between Hb (A1c) and diurnal BG obtained under standardized conditions - before breakfast, two hours after breakfast, before lunch, two hours after lunch, before dinner, two hours after dinner, and at 10 PM, 12 midnight and 3 AM in 68 type 2 diabetic patients before and after optimizing glycemic control. The areas under the curve above fasting BG (AUC1) and above 5.6 mmol/l (AUC2) were calculated for further evaluation. Hb (A1c) was measured at baseline and after a mean of 89 (74 to 108) days. RESULTS: Each BG value at baseline and after treatment optimization significantly correlated with baseline and follow-up Hb (A1c), respectively. The pre-breakfast BG showed the closest correlation with Hb (A1c). The relative contribution of postprandial BG concentrations (AUC1) to overall hyperglycemia (AUC2) decreased with poorer glycemic control. However, treatment optimization mainly resulted in improved blood glucose values in patients with the poorest glycemic control at baseline. Multiple regression analysis demonstrated that fasting (AUC2-AUC1) and postprandial (AUC1) hyperglycemia independently determined Hb (A1c) or the change in Hb (A1c) after treatment optimization. CONCLUSIONS: Our findings indicate that intensive blood glucose monitoring during fasting and postprandial states is important for glycemic control, and is therefore an essential part of good clinical practice.     

Blood glucose discrimination training with insulin-dependent diabetics: a clinical note

Two insulin-dependent diabetic adults were exposed to a blood glucose discrimination training program. Following baseline, during which subjects estimated their blood glucose levels twice daily, subjects received immediate feedback regarding the accuracy of their estimates. The procedure resulted in a large increase in accuracy of blood glucose level estimation. The implications of the findings were discussed.     

Studies of growth hormone secretion in juvenile diabetes.

To further investigate the GH secretion in juvenile diabetics, blood glucose (BG) and plasma growth hormone (GH) were determined during controlled exercise performed in basal condition and under glucose infusion, in 7 controls and 22 juvenile diabetics aged 12--35 years, 10 of them with fundal vascular lesions. In controls, glucose infusion significantly lowered the exercise induced GH rise observed under basal conditions. In diabetics, under basal conditions, diabetics with low basal BG (BG less than 100 mg/100ml) had higher GH secretion than those with high basal BG (BG greater than 140 mg/100 ml; p less than 0.05). Under glucose infusion, diabetics with normal BG peak values (not different from controls: BG = 284 +/- (SK) 45 mg/100 ml) had significantly higher plasma GH levels than controls (p less than 0.01). In contrast, in diabetics with BG peak value higher than controls (BG greater than 374 ng/100 ml), plasma GH levels were not different from control values. This study indicates that exercise induced GH secretion in diabetics is mainly related to actual BG levels. Furthermore, we found no relation between the magnitude of GH secretion and the presence of retinopathy in diabetics.     

Various Blood Glucose Parameters that Indicate Hyperglycemia after Intravenous Thrombolysis in Acute Ischemic Stroke Could Predict Worse Outcome

Background

Hyperglycemia is common after stroke, and it is well known to worsen its outcome. However, it is important to consider that blood glucose (BG) levels can undergo dynamic changes during the acute stage of ischemic stroke. We sought to investigate the clinical significance of various glucose parameters within first 24 hours in acute ischemic stroke (AIS). The study focused on hyperacute stage patients who underwent IVT and investigated which parameters of glucose demonstrated to be helpful for predicting outcome.

Methods

This was a retrospective study of consecutive patients with AIS at a single stroke center. Patients were consecutively enrolled if they were treated with IV-tPA within 3 hours of symptom onset. BG was measured immediately upon arrival in ER, after IVT and every 6–8 hours during the first 24 hours after IVT. The various parameters of BG were the following: BG before IVT, BG after IVT, mean BG (mBG), maximal BG (max BG), standard deviation of BG (sdBG), and standard deviation of mean BG (sdmBG).

Results

207 patients (127 men and 80 women) were included in this study. Seventy seven of 207 patients had favorable outcomes at 3 months. High BG after IVT, mBG and max BG were independently associated with mRS>2 at 3 months (adjusted by age, NIHSS, and atrial fibrillation). Several parameters of BG were also independently associated with early mortality within 3 months (BG after IVT, mBG, and max BG). BG after IVT and mBG over 180 mg/dL were independently associated with early mortality within 3 months.

Conclusion

Serial measurements of BG might be a better predictor of clinical outcome in patients with AIS treated with IVT than single BG measurements before IVT. Therefore, these results suggest that variable parameters of BG could be important for the prediction of clinical outcome in AIS treated with IVT.     

Blood glucose discrimination training with insulin-dependent diabetics: A clinical note

Two insulin-dependent diabetic adults were exposed to a blood glucose discrimination training program. Following baseline, during which subjects estimated their blood glucose levels twice daily, subjects received immediate feedback regarding the accuracy of their estimates. The procedure resulted in a large increase in accuracy of blood glucose level estimation. The implications of the findings were discussed.The authors thank Joe Quattrini, Maria Bohnert, Jenifer Dale, Kathy Cogan, and Ruth Tarlow for their help in conducting this study. This research was supported in part by Grant AM 30840 from the National Institutes of Health.     

Glycated Albumin at 4 Weeks Correlates with A1C Levels at 12 Weeks and Reflects Short-Term Glucose Fluctuations

Objective: Evaluate the performance of glycated albumin (GA) monitoring by comparing it to other measures of glycemic control during intensification of antidiabetic therapy.Methods: This 12-week, prospective, multicenter study compared the diagnostic clinical performance of GA to glycated hemoglobin A1C (A1C), fructosamine corrected for albumin (FRA), fasting plasma glucose (FPG), and mean blood glucose (MBG) estimated from self-monitoring of blood glucose (SMBG) and continuous glucose monitoring (CGM) in 30 patients with suboptimally controlled type 1 or 2 diabetes.Results: Mean A1C decreased from 9.5% to 8.1%. Mean SMBG correlated closely with CGM (Pearson r = 0.783 for daily estimates and r = 0.746 for weekly estimates, P<.0001). Both GA and FRA levels significantly correlated with changes from baseline in A1C and mean weekly SMBG (P<.001). The lowest observed median GA occurred at 4 weeks, followed by a small increase and then a slight reduction, mirroring changes in overall mean SMBG values. The median A1C fell throughout the treatment period, failing to reflect short-term changes in SMBG. A ≥1% reduction in GA at 4 weeks was significantly associated with a ≥0.5% change in A1C at 12 weeks (odds ratio &lsqb;OR] = 19.0, 95% confidence interval &lsqb;CI]: 1.4, 944, P = .018).Conclusion: In patients receiving glucose-lowering therapy, changes in GA at 4 weeks were concordant with changes in A1C at 12 weeks, and both GA and FRA more accurately reflected short-term blood glucose fluctuations than A1C.Abbreviations: A1C = glycated hemoglobin A1C ARIC = Atherosclerosis Risk in Communities CGM = continuous glucose monitoring FPG = fasting plasma glucose FRA = fructosamine corrected for albumin GA = glycated albumin MBG = mean blood glucose OR = odds ratio SMBG = self-monitoring of blood glucose     

Glycemic Control with use of Insulin Glargine after Cardiothoracic Surgery: A Retrospective Study

ObjectivePerioperative glycemic control in critically ill cardiothoracic surgery patients may improve postsurgical outcomes. The objective of the study was to compare outcomes before and after the implementation of a protocol using subcutaneous (SC) glargine at transition from intravenous insulin infusion (IVII).MethodsIn August 2006, the Cleveland Clinic began using glargine and supplemental rapid-acting sliding scale insulin (SSI) at transition from IVII (glargine-SSI group). Before August 2006, only supplemental insulin was used (SSI-only group). The primary outcome was first blood glucose (BG1) after discontinuation of IVII. Secondary outcomes included the absolute difference between the last glucose before discontinuation of IVII (BG0) and BG1, mean glucose in the first 24 hours after discontinuation of IVII (BG24), need for SSI, and hypoglycemia.ResultsMean BG0, BG1, and BG24, and the difference between BG1 and BG0 and between BG24 and BG0 were not significantly different between groups. Diabetes mellitus (DM) patients who had received glargine had a lower mean difference between BG1 and BG0 and a lower mean BG24 than those who had not received glargine (14.6 mg/dL vs. 33.1 mg/dL; P = .20, and 163.8 mg/dL vs. 177.9 mg/dL; P = .29, respectively). A higher proportion of DM patients needed SSI than did non-DM patients (82% vs. 36%; P<.001).ConclusionGlargine administered at the cessation of IVII enabled less SSI coverage in diabetic patients subsequent to transition from IVII. However, there was no significant difference in BG control between the glargine-SSI and SSI-only groups. Prospective studies involving more patients are needed to show possible clinically significant benefits of this intervention. (Endocr Pract. 2013;19:485-493)     

Dicrimination of systolic blood pressure

The ability of humans to discriminate systolic blood pressure (BP) was investigated in two experiments. In Experiment 1, 14 normal subjects were asked to make estimates of their systolic BP while performing both BP-elevating and BP-lowering tasks. They were given intermittent feedback throughout all 10 45-min sessions. Results indicated significant correlations and small absolute differences between estimated and measured BP for all subjects in almost all sessions. Experiment 2, undertaken 6 months after Experiment 1, assessed whether estimation accuracy by subjects who had available both external and interoceptive cues surpassed that of subjects which access to external cues only. Three subjects from the original group who showed consistently high motivation, and who improved in accuracy across the 10 sessions in the previous experiment, made estimates of BP while performing novel tasks with no feedback. Correlations between estimated and measured BP remained high for 2 of the 3. These results were compared with the accuracy of control subjects (3 for each experimental subject) who were asked to estimate experimental subjects' BP using only the cognitive information available to the experimental subjects. Control subjects also had high correlations between their estimates and the experimental subjects' measured BP but at lower levels than two experimental subjects. These findings are discussed in relation to subjects' possible use of interoceptive information.     

Using Meal-Based Self-Monitoring of Blood Glucose as a Tool to Improve Outcomes in Pregnancy Complicated By Diabetes

ObjectiveTo review the importance of controlling blood glucose levels and the role of self-monitoring of blood glucose (SMBG) in the management of pregnancy complicated by diabetes.MethodsThis report describes the relationship between hyperglycemia and maternal and neonatal complications, reviews the utility of meal-based SMBG in modifying food choices and adjusting insulin doses, and proposes an algorithm to achieve normoglycemia in pregnancies complicated by diabetes.ResultsThe risk of diabetes-related complications in pregnancy is more strongly associated with 1-hour post-prandial plasma glucose concentrations than with fasting plasma glucose levels. SMBG strategies that incorporate postprandial glucose testing provide better glycemic control and greater reductions in risk of complications than does preprandial glucose testing alone. Although the optimal timing and frequency of SMBG remain controversial, available clinical evidence supports testing 4 times per day (before breakfast and 1 hour after each meal) in women with gestational diabetes managed by medical nutrition therapy only and 6 times per day (before and 1 hour after each meal) in pregnant women treated with insulin.ConclusionMeal-based SMBG is a valuable tool for improving outcomes in pregnancy complicated by diabetes. The lessons learned in this setting should have relevance to the general population of patients with diabetes, in whom microvascular and macrovascular complications are the outcomes of importance. (Endocr Pract. 2008; 14:239-247)     

A pilot study to stabilize normoglycemia during an educational camp for children and adolescents with type 1 diabetes mellitus

Background: Children and adolescents with type 1 diabetes mellitus (DM) who participate in diabetes camps do not often achieve stable, normoglycemic control, largely because changes in the campers' activity levels and food options necessitate adjustments to their insulin use and nutritional therapies. It would seem logical, with the abundance of diabetes education and professional consultation freely available at these camps, that the glycemic levels of these young campers could approach normal values.Objective: This informal study was designed to explore the feasibility of safely achieving stable, short-term normo-glycemic control in children and adolescents with recent-onset type 1 DM attending a diabetes camp.Methods: A multidisciplinary team worked with children and adolescents 6 to 18 years of age during a residential 3-day/2-night diabetes camp. Demographic data were compiled from the application forms completed by the campers and signed by the campers and their parents. The staff functioned in 2 distinct roles: as managers (securing time, task, technique, and territory boundaries) and as consultants (addressing participants' educational, social, and emotional needs). The staff supported the campers in their attempts to quickly and safely achieve tight normoglycemic control (ie, 71–99 mg/dL) and stability (ie, an estimated mean amplitude of glycemic excursion [eMAGE] score ≤95) through their firsthand experience with self-directed learning methods, basal-bolus insulin analogue therapy, and a diet low in concentrated carbohydrates (CHOs). Campers chose foods from meal buffets, calculated preprandial and complementary doses of ultra-rapid insulin, and participated in physical exercise and self-monitoring of blood glucose (SMBG) at will. SMBG values retained in each camper's combined glucose/ketone monitor furnished statistical data. Initial and final glycosylated hemoglobin values were not measured because 3 days of glycemic control—at any BG level—would not be expected and have not been reported to produce significant changes. No follow-up of the campers was planned or possible.Results: Six boys and 3 girls (aged 8–17 years; mean [SD] age, 11.8 [2.6] years; mean duration of diabetes, 1.62 [0.88] years) agreed to participate in the study. All but 1 of the campers were preadolescents. Mean BG levels on arrival and departure were 209 (101.5) and 81 (12.8) mg/dL, respectively (P < 0.003). The mean 3-day BG level was 95 (21.2) mg/dL. The 3-day mean eMAGE score (66.5 [28.1]) indicated stable glycemic control. Seven of the 9 campers (78%) returned to the camp the following year (2007).Conclusions: Combining self-directed educational methods for learning diabetes self-management with insulin analogues in a basal-bolus therapy regimen, ad libitum physical activity and SMBG, and a diet low in concentrated CHOs, campers rapidly established routinely normal daily mean BG levels and glycemic stability.     

Effect of canagliflozin on renal threshold for glucose, glycemia, and body weight in normal and diabetic animal models

Background

Canagliflozin is a sodium glucose co-transporter (SGLT) 2 inhibitor in clinical development for the treatment of type 2 diabetes mellitus (T2DM).

Methods

¹⁴C-alpha-methylglucoside uptake in Chinese hamster ovary-K cells expressing human, rat, or mouse SGLT2 or SGLT1; ³H-2-deoxy-d-glucose uptake in L6 myoblasts; and 2-electrode voltage clamp recording of oocytes expressing human SGLT3 were analyzed. Graded glucose infusions were performed to determine rate of urinary glucose excretion (UGE) at different blood glucose (BG) concentrations and the renal threshold for glucose excretion (RT_G) in vehicle or canagliflozin-treated Zucker diabetic fatty (ZDF) rats. This study aimed to characterize the pharmacodynamic effects of canagliflozin in vitro and in preclinical models of T2DM and obesity.

Results

Treatment with canagliflozin 1 mg/kg lowered RT_G from 415±12 mg/dl to 94±10 mg/dl in ZDF rats while maintaining a threshold relationship between BG and UGE with virtually no UGE observed when BG was below RT_G. Canagliflozin dose-dependently decreased BG concentrations in db/db mice treated acutely. In ZDF rats treated for 4 weeks, canagliflozin decreased glycated hemoglobin (HbA1c) and improved measures of insulin secretion. In obese animal models, canagliflozin increased UGE and decreased BG, body weight gain, epididymal fat, liver weight, and the respiratory exchange ratio.

Conclusions

Canagliflozin lowered RT_G and increased UGE, improved glycemic control and beta-cell function in rodent models of T2DM, and reduced body weight gain in rodent models of obesity.     

Real-Time Continuous Glucose Monitoring Shows High Accuracy within 6 Hours after Sensor Calibration: A Prospective Study

Accurate and timely glucose monitoring is essential in intensive care units. Real-time continuous glucose monitoring system (CGMS) has been advocated for many years to improve glycemic management in critically ill patients. In order to determine the effect of calibration time on the accuracy of CGMS, real-time subcutaneous CGMS was used in 18 critically ill patients. CGMS sensor was calibrated with blood glucose measurements by blood gas/glucose analyzer every 12 hours. Venous blood was sampled every 2 to 4 hours, and glucose concentration was measured by standard central laboratory device (CLD) and by blood gas/glucose analyzer. With CLD measurement as reference, relative absolute difference (mean±SD) in CGMS and blood gas/glucose analyzer were 14.4%±12.2% and 6.5%±6.2%, respectively. The percentage of matched points in Clarke error grid zone A was 74.8% in CGMS, and 98.4% in blood gas/glucose analyzer. The relative absolute difference of CGMS obtained within 6 hours after sensor calibration (8.8%±7.2%) was significantly less than that between 6 to 12 hours after calibration (20.1%±13.5%, p<0.0001). The percentage of matched points in Clarke error grid zone A was also significantly higher in data sets within 6 hours after calibration (92.4% versus 57.1%, p<0.0001). In conclusion, real-time subcutaneous CGMS is accurate in glucose monitoring in critically ill patients. CGMS sensor should be calibrated less than 6 hours, no matter what time interval recommended by manufacturer.     

Positioning Accuracy in Otosurgery Measured with Optical Tracking

Objectives

To assess positioning accuracy in otosurgery and to test the impact of the two-handed instrument holding technique and the instrument support technique on surgical precision. To test an otologic training model with optical tracking.

Study Design

In total, 14 ENT surgeons in the same department with different levels of surgical experience performed static and dynamic tasks with otologic microinstruments under simulated otosurgical conditions.

Methods

Tip motion of the microinstrument was registered in three dimensions by optical tracking during 10 different tasks simulating surgical steps such as prosthesis crimping and dissection of the middle ear using formalin-fixed temporal bone. Instrument marker trajectories were compared within groups of experienced and less experienced surgeons performing uncompensated or compensated exercises.

Results

Experienced surgeons have significantly better positioning accuracy than novice ear surgeons in terms of mean displacement values of marker trajectories. The instrument support and the two-handed instrument holding techniques significantly reduce surgeons’ tremor. The laboratory set-up presented in this study provides precise feedback for otosurgeons about their surgical skills and proved to be a useful device for otosurgical training.

Conclusions

Simple tremor compensation techniques may offer trainees the potential to improve their positioning accuracy to the level of more experienced surgeons. Training in an experimental otologic environment with optical tracking may aid acquisition of technical skills in middle ear surgery and potentially shorten the learning curve. Thus, simulated exercises of surgical steps should be integrated into the training of otosurgeons.     

Ultradian, Circadian and Circannual Rhythms of Blood Glucose and Injected Insulins Documented in Six Self-Controlled Adult Diabetics

The aim of the study was to document during one to two years individual rhythmic patterns in blood glucose and injected insulin in self-controlled insulin dependent (C-peptide negative) diabetics with home blood glucose monitoring. Two females and four males with diurnal activity from 0700 to 2300 self-determined their blood glucose three to six times a day over a period of 12-27 months. Circadian and ultradian rhythms were analysed for each subject on a monthly basis to document annual rhythms. Blood glucose (BG) estimated circadian acrophases were located between 2200 and 0300 for all patients and months with few exceptions. A correlation was found between circadian mesors and amplitudes of BG in four subjects. Annual changes in BG were validated for each subject with large interindividual differences in peak times. The individual mean of injected insulin (II) varied from 40 to 80 iU with annual changes validated for each subject. A group pattern was observed with a peak time either in the autumn (four patients) or in the summer (two patients). A circadian rhythm of II was detected in almost all monthly means and for all patients. Locations of computed peak time φ of II exhibited a great stability for a given individual but large interindividual differences. Thus the rather constant φ location of BG for all subjects contrasted with interindividual differences in φ locations of II. These results suggest that rhythmic changes in BG and II should be recognized when forming a realistic strategy for timing and dosing time(s) of insulin.