Effects of anthropometric factors on nerve conduction: an electrophysiologic study of feet

Acute Effects of a Whole Body Vibration Session on the Vibration Perception Threshold in Patients with Type 2 Diabetes Mellitus

BACKGROUND

Type 2 Diabetes Mellitus (T2DM) is a chronic disease that affects millions of people, and according to the International Diabetes Federation, 46.5% of people have undiagnosed diabetes. One of the most common complications of diabetes mellitus is loss of peripheral sensation. Whole Body Vibration (WBV) is a therapy, and it would be interesting to know if it can be considered as a training method to improve the Vibration Perception Threshold (VPT). The aim of the study is to verify whether there are really acute effects on the VPT after a WBV training session in people with T2DM.

METHODS

Ninety people with T2DM (56 men and 34 women) were randomly allocated to two groups: the WBV group and the placebo group. The ninety subjects went through a VPT training test before receiving the assigned intervention, and they performed the VPT test using the Vibratron II device.

RESULTS

After one session of WBV, an increase of the VPT in the WBV group was found, with respect to the placebo group.

CONCLUSIONS

Vibration perception threshold is increased after a WBV training session in people with T2DM, compared to a placebo group.

Test-Retest Reliability of Vibration Perception Threshold Test in People with Type 2 Diabetes Mellitus

BACKGROUND

Diabetes mellitus is a chronic disease characterized by fasting hyperglycemia. It affects approximately 415 million people worldwide and involves a variety of complications. One of them is the loss of sensitivity to peripheral vibration.

OBJECTIVE

Our study aims to discover the test-retest reliability of a procedure for assessing vibration sensitivity in people with type 2 diabetes mellitus.

METHODOLOGY

90 people with type 2 diabetes mellitus (56 men and 34 women) performed the vibration perception threshold (VPT) test using the Vibratron II device. A re-test was completed seven days after the first reading.

RESULTS

The relative reliability of the VPT test result is excellent (intraclass correlation coefficient = 0.96). The same applies to gender and obesity subgroups. Regarding absolute reliability, the standard error of measurement is 8.99%, and the small real difference is 24.94%.

CONCLUSIONS

The relative and absolute reliability results of the vibration perception threshold in people with type 2 diabetes mellitus offer excellent results.

Impaired vibrotactile sense in children and adolescents with type 1 diabetes - Signs of peripheral neuropathy

Objective

To investigate whether multi-frequency vibrometry can identify individuals with elevated vibration perception thresholds (VPTs), reflecting impaired vibrotactile sense, among children and adolescents with type 1 diabetes.

Methods

In 72 pediatric patients with type 1 diabetes, VPTs were evaluated for seven frequencies on two sites of the hand, and five frequencies on two sites of the foot. Z-scores, based on previously collected reference data, were calculated. Perception to light touch was investigated using monofilaments. Subjects’ characteristics were analyzed in comparison to normal and impaired vibrotactile sense.

Results

Subjects’ median age, disease duration and age at disease onset were 12.8, 5.3 and 6.9 years, respectively. A total of 13 out of 72 (18%) subjects had impaired vibrotactile sense on at least one foot site. Impaired vibrotactile sense was more common among subjects treated with multiple daily insulin injections (MDI) compared to subjects treated with continuous subcutaneous insulin infusion (CSII) (p = 0.013). Age at disease onset was higher among subjects with impaired vibrotactile sense (p = 0.046). No significant correlations were found with gender, HbA1c or duration of diabetes.

Conclusions

Impaired vibrotactile sense, mirroring diabetic peripheral neuropathy, was found in 1/5 of the children and adolescents in the study, and was more common in patients treated with MDI than in subjects treated with CSII.

Reproducibility of vibration perception threshold values in children and adolescents with type 1 diabetes mellitus and associated factors

AIMS

To define the reproducibility of vibration perception thresholds (VPTs) and the possible associated factors, as an early index of peripheral diabetic neuropathy (PDN) in type 1 diabetes mellitus (T1DM) children and adolescents.

METHODS

A single examiner studied 118 T1DM subjects (aged 13.5±3.4 years) and 79 controls (aged 12.0±3.07 years). Glycaemic control was assessed with HbA1c levels. VPT was measured twice on upper and lower limbs, using a Biothesiometer. Concordance between the two VPT measurements was evaluated using the Cohen's Weighted Kappa statistic (Kappa=0.41-0.60→moderate concordance, Kappa=0.61-0.80→substantial concordance).

RESULTS

T1DM children had significantly higher VPTs than controls at all sites (p=0.001), but with lower Kappa values (0.64-0.70). VPT values increased in parallel with HbA1c (a.<8%, b. 8-9.5%, c.>9.5%) and T1DM duration (a.<5 years, b.5.1-10, c.>10 years). However, Kappa values were lower in the groups with the poorest control (HbA1c>9.5%) (Kappa=0.54-0.76) or the longest T1DM duration (>10 years) (Kappa=0.49-0.71). Although VPTs increased with stature and male gender, no effect on VPT reproducibility was observed. However, obesity was associated with lower VPT values and poorer concordance.

CONCLUSIONS

These findings suggest that the reproducibility of VPTs is lower in the high-risk patients for early subclinical PDN development, who need a regular follow-up.

Optimizing electrical impedance myography measurements by using a multifrequency ratio: a study in Duchenne muscular dystrophy

OBJECTIVE

Electrical impedance myography (EIM) is an electrophysiological technique for neuromuscular evaluation that is impacted by subcutaneous fat (SF). Exploiting the differing frequency dependences of muscle and fat, we assessed a 2-frequency EIM phase ratio in Duchenne muscular dystrophy (DMD) boys.

METHODS

Twenty-eight DMD boys aged 2-13years underwent EIM and the 6-minute walk test (6MWT). For each subject, 50kHz phase data was input into the numerator while 20-500kHz phase values were input into the denominator. We then performed correlation analyses seeking to identify the denominator frequency that simultaneously optimized SF and 6MWT correlations. This optimized ratio was then tested in 24 healthy boys.

RESULTS

50kHz phase correlated to 6MWT in DMD boys with R=0.52, p=0.0066, and to SF thickness with R=-0.67, p<0.001. An optimized ratio of 50/200kHz phase reduced the correlation of SF thickness to R=-0.075, p=0.45 while improving the relationship to the 6MWT (R=0.60, p=0.001). In normal subjects, the optimization decreased SF correlation from R=0.61 from R=0.16 with 6MWT correlation remaining unchanged.

CONCLUSIONS

The 50/200kHz EIM phase ratio removes the impact of SF while maintaining EIM's association with function.

SIGNIFICANCE

The use of a phase ratio may enhance EIM's application for evaluation of neuromuscular disease.