Long-term hyperglycemia is related to peripheral nerve changes at a diabetes duration of 4 years. The Wisconsin Diabetes Registry

Assessment of sensory neuropathy in patients with diabetic foot problems

Our aim of this study was to compare the accuracy of three different modalities for testing sensory neuropathy in diabetic patients with and without diabetic foot problems. The three devices used included the pin-prick testing using the Neurotip® (PPT), the Semmes-Weinstein 5.07/10 g monofilament testing (SWMT), and the rapid-current perception threshold (R-CPT) measurements using the Neurometer® testing. Our study population consisted of 54 patients (108 feet) with diabetic foot problems treated at the National University Hospital in Singapore by our multi-disciplinary diabetic foot care team. Our results showed no difference in sensory neuropathy detected by PPT and 5.07/10 g SWMT in both the pathological and normal foot. In the pathological foot, there was significant increase in sensory neuropathy detected by the Neurometer® device at both the big toe and ankle sites as compared to PPT and 5.07/10 g SWMT. In the normal foot, there was a significant increase in sensory neuropathy detected by the Neurometer® device at the big toe site only as compared to PPT and 5.07/10 g SWMT. Finally, the Neurometer® measurements detected a statistically higher proportion of feet with sensory neuropathy as compared to detection by the PPT or 5.07/10 g SWMT.

Increases in central aortic impedance precede alterations in arterial stiffness measures in type 1 diabetes

OBJECTIVE

Increased pulse pressure has been associated with increased cardiovascular risk in individuals with diabetes. Changes in central aortic properties can increase central pulse pressure and may adversely affect microvascular perfusion and cardiac performance. This study was performed to define early changes in central arterial properties in a group of young individuals with type 1 diabetes.

RESEARCH AND DESIGN METHODS

Seventeen individuals with type 1 diabetes and their nondiabetic control subjects who were participating in the Cardio-Diab Study had arterial stiffness and pulsatile hemodynamics measured with calibrated tonometry and pulsed Doppler. Aortic characteristic impedance (Z(c)) was calculated from the ratio of change in carotid pressure and aortic flow in early systole. Pulse wave velocity (PWV) was assessed from tonometry and body surface measurements.

RESULTS

Duration of type 1 diabetes was 15.3 +/- 0.7 (mean +/- SD) years. In type 1 diabetic subjects, central pulse pressure was elevated (45 +/- 11 vs. 36 +/- 10 mmHg in control subjects, P = 0.02), as was peripheral pulse pressure (54 +/- 13 vs. 43 +/- 10 mmHg, P = 0.002). Z(c) was elevated in type 1 diabetes (179 +/- 57 vs. 136 +/- 42 dynes x s/cm5 in control subjects, P = 0.004), whereas PWV was not different (5.9 +/- 0.9 vs. 5.9 +/- 0.7 m/s in type 1 diabetic vs. control subjects, respectively; NS). There was a moderate correlation between Z(c) and urinary albumin excretion (coefficient 0.39, P = 0.02).

CONCLUSIONS

Z(c) appears to be increased early in type 1 diabetes, before elevation of PWV and is associated with higher pulse pressure, which may contribute to renal microvascular damage in diabetes.

Diabetes, aging, and cognitive decline

Type 1 diabetes is associated with cognitive changes in children and adults, but the extent to which cognition declines with increasing age, and increasing duration of diabetes, remains poorly understood. This cross-sectional study assessed neuropsychological performance on 200 diabetic and 175 nondiabetic adults, 18-64 years of age, stratified into five age bands. Similar age-related cognitive declines were seen on measures of problem-solving, learning and memory, and psychomotor speed, but it was only on the latter measure that diabetic and nondiabetic subjects differed significantly. The best predictor of psychomotor slowing was the presence of clinically significant biomedical complications, particularly proliferative retinopathy, peripheral neuropathy, and peripheral vascular disease (PVD). It now appears that psychomotor slowing is the fundamental cognitive deficit associated with diabetes mellitus; why other cognitive skills are relatively unaffected remains poorly understood.

Nerve conduction in children suffering insulin dependent diabetes mellitus

OBJECTIVE

To determine the incidence of peripheral neuropathy in children suffering Insulin Dependent Diabetes Mellitus (IDDM) as well as to determine the relationship between other criteria of the disease and neuropathy.

METHODS

40 children (17 males, mean age 11.9 years) suffering IDDM and receiving insulin therapy involving two injections a day and 30 healthy children (17 males, mean age 11.7 years) were included in the study. They were inquired about their demographical characteristics as well as the presence of neurological symptoms. Their detailed neurological examinations were conducted. Their glycemic control values (Hb A1C) were recorded, and their nerve conduction studies were performed from right upper and lower extremities.

RESULTS

All nerve conduction values of children with IDDM were found to be significantly lower (p<0.0001) as compared to the control group. 60% of diabetic children (n=24) were found to suffer peripheral neuropathy. Statistically significant relationships were found between the glycemic control values and the peroneal, sural, tibial, ulnar and median nerve conduction velocities, and also between the duration of disease and the peroneal, sural, tibial and median nerve conduction velocities.

CONCLUSION

The peripheral neuropathy is rather a frequently observed complication in diabetic children. The duration of disease and impaired glycemic control play an important role in the development of neuropathy. The introduction of new methods designed to ensure better glycemic control will reduce the incidence of the complication.

Local insulin injection improves median nerve regeneration in NIDDM patients with carpal tunnel syndrome

It has been suggested that insulin has an effect on nerve regeneration similar to that of nerve growth factor (NGF). Therefore, we aimed to evaluate the effectiveness of local insulin injection on median nerve in patients with non-insulin-dependent diabetes (NIDDM) mellitus who have mild-to-moderate carpal tunnel syndrome (TS). We carried out a prospective, randomized, double-blind, placebo-controlled study in these patients. At the baseline, 20 mg methylprednisolone was injected directly into the carpal tunnel in all patients [n=43 (62 hands)]. A week after prednisolone, the placebo or NPH insulin (12 U) was injected into the carpal tunnel weekly for 7 weeks. The patients were followed up for 23 weeks. A significant improvement in mean median nerve motor distal latency (MNMDL), median nerve sensory velocity (MNSV), and global symptom score (GSS) occurred in both groups (with the exception of mean MNMDL in the placebo group). A more significant improvement in the mean MNMDL, MNSV, and GSS was observed in the insulin group when compared with the placebo group. This study suggests that local insulin treatment may be of great potential benefit in the improvement of nerve functions in NIDDM patients with mild-to-moderate CTS who opt for conservative treatment.

'Numbness of the feet' is a poor indicator for polyneuropathy in Type 2 diabetic patients

AIMS

To identify neuropathic sensory symptoms associated with a clinical neurological examination (CNE) and to investigate whether these symptoms could be used as a diagnostic or screening tool for diabetic polyneuropathy in general practice.

METHODS

Five hundred and eighty-eight patients with Type 2 diabetes, recruited from 26 general practices in the Netherlands, underwent a CNE and completed a diabetes symptom checklist that included 10 items on neuropathic sensory symptoms. Linear regression analyses were performed to assess the association between neuropathic symptoms and CNE. Receiver operating characteristic (ROC) curves were created to assess the diagnostic properties of neuropathic symptoms.

RESULTS

In this population, with a mean age of 66.8 years, 32% were identified with diabetic polyneuropathy according to the CNE. Variables that showed the strongest association with CNE score were age (beta = 0.41), symptoms of sensory alteration (beta = 0.27), and the item 'numbness of the feet' (beta = 0.35) in particular. ROC curves showed that prediction of diabetic polyneuropathy from these symptoms was unsatisfying. The sensitivity and specificity of daily symptoms of 'numbness of the feet' were 28% and 93%, respectively, in patients <68 years, and 22% and 92%, respectively, in patients > or =68 years.

CONCLUSIONS

Identification of neuropathic sensory symptoms is not useful as a diagnostic or even a screening tool in the assessment of diabetic neuropathy in daily practice. Therefore, the results reported in this paper mandate an annual foot examination by the general practitioner.

Self-efficacy in chronic illness: the juxtaposition of general and regimen-specific efficacy

Changes in lifestyle are difficult for most people but necessary for those with a chronic illness, for whom changes may involve, among other adjustments, learning new behaviours and/or modifying one's lifestyle. The ease with which such changes occur depends on the person's efficacy beliefs and outcome expectations. This paper will discuss the conceptual issues related to self-efficacy: general, domain, and specific. Examples will be drawn from the health-related behaviour changes required to manage diabetes and rheumatoid arthritis. For this paper, regimen-specific or task-specific behaviour refers to the multiple tasks that the person carries out for management of their chronic illness. Confounding the issue of perceived efficacy (general, domain or specific), is the fact that compliance with all aspects of a recommended self-care regimen will not necessarily result in metabolic control for the person with type 1 diabetes mellitus, weight loss for the person with type 2 diabetes mellitus, or pain control for the arthritic person.