Neuroretinal dysfunction revealed by a flicker electroretinogram correlated with peripheral nerve dysfunction and parameters of atherosclerosis in patients with diabetes

AIMS/INTRODUCTION

Diabetic polyneuropathy (DPN) develops in the early stage of diabetes. However, no common diagnostic protocol has yet been established. Here, to verify that the flicker electroretinogram using a hand-held device can detect the early dysfunction of the peripheral nervous system in patients with diabetes, we investigated the correlation between the progression of DPN and neuroretinal dysfunction.

MATERIALS AND METHODS

In total, 184 participants with type 1 or 2 diabetes underwent a flicker electroretinogram (ERG) using a hand-held device RETeval™ and nerve conduction study. Participants were also evaluated for intima-media thickness, ankle-brachial index, toe brachial index and brachial-ankle pulse wave velocity. Parameters of the nerve conduction study were used to diagnose the severity according to Baba's classification. A multiple regression analysis was used to examine the associations of ERG parameters with the severity of DPN categorized by Baba's classification. Diagnostic properties of the device in DPN were evaluated using a receiver operating characteristic curve.

RESULTS

A multiple regression model to predict the severity of DPN was generated using ERG. In the model, moderate-to-severe DPN was effectively diagnosed (area under the receiver operating characteristic curve 0.692, sensitivity 56.5%, specificity 78.3%, positive predictive value 70.6%, negative predictive value 66.1%, positive likelihood ratio 2.60, negative likelihood ratio 0.56). In the patients without diabetic retinopathy, the implicit time and amplitude in ERG significantly correlated with the parameters of the nerve conduction study, brachial-ankle pulse wave velocity and intima-media thickness.

CONCLUSIONS

Electroretinogram parameters obtained by the hand-held device successfully predict the severity of DPN. The device might be useful to evaluate DPN.

Validity and reliability of a point-of-care nerve conduction device in diabetes patients

AIMS/INTRODUCTION

Although nerve conduction study (NCS) using a standard electromyography system (EMGS) is considered to be the gold standard in evaluating diabetic polyneuropathy, this examination requires expensive equipment and well-trained technicians. We aimed to validate a point-of-care device, NC-stat/DPNCheck™, that has been developed for widespread use of NCS in diabetic polyneuropathy.

MATERIALS AND METHODS

Diabetes patients underwent two kinds of NCS: DPNCheck™ and electromyography system. Inter-/intrarater reliability of DPNCheck™ were also determined by the intraclass correlation coefficient.

RESULTS

A total of 57 patients were evaluated. The parameters of NCS between the two methods correlated well (r = 0.7734 for the sural nerve conduction velocity, r = 0.6155 for the amplitude of sural nerve action potential). The intraclass correlation coefficients were excellent (intrarater: the velocity 0.767, the amplitude 0.811; interrater: the velocity 0.974, the amplitude 0.834).

CONCLUSIONS

The point-of-care device has excellent reproducibility and good agreement with standard electromyography system. The device might be useful to evaluate diabetic polyneuropathy.