Simplified electrophysiological approach combining a point-of-care nerve conduction device and an electrocardiogram produces an accurate diagnosis of diabetic polyneuropathy.

This study aimed to investigate the diagnostic potential of two simplified tests, a point-of-care nerve conduction device (DPNCheck™) and a coefficient of variation of R-R intervals (CVR-R), as an alternative to traditional nerve conduction studies for the diagnosis of diabetic polyneuropathy (DPN) in patients with diabetes. Inpatients with type 1 or type 2 diabetes (n = 167) were enrolled. The study population consisted of 101 men, with a mean age of 60.8 ± 14.8 years. DPN severity was assessed using traditional nerve conduction studies, and differentiated based on Baba's classification (BC). To examine the explanatory potential of variables in DPNCheck™ and CVR-R regarding the severity of DPN according to BC, a multiple regression analysis was carried out, followed by a receiver operating characteristic analysis. Based on BC, 61 participants (36.5% of the total) were categorized as having DPN severity of stage 2 or more. The multiple regression analysis yielded a predictive formula with high predictive power for DPN diagnosis (estimated severity of DPN in BC = 2.258 - 0.026 × nerve conduction velocity [m/s] - 0.594 × ln[sensory nerve action potential amplitude (μV)] + 0.528In[age(years)] - 0.178 × ln[CVR-R], r = 0.657). The area under the curve in receiver operating characteristic analysis was 0.880. Using the optimal cutoff value for DPN with severer than stage 2, the predictive formula showed good diagnostic efficacy: sensitivity of 83.6%, specificity of 79.2%, positive predictive value of 51.7% and negative predictive value of 76.1%. These findings suggest that DPN diagnosis using DPNCheck™ and CVR-R could improve diagnostic efficiency and accessibility for DPN assessment in patients with diabetes.

Hayashi Y ，Himeno T ，Shibata Y ，Hirai N ，Asada-Yamada Y ，Sasajima S ，Asano-Hayami E ，Motegi M ，Asano S ，Kato M ，Nakai-Shimoda H ，Tani H ，Miura-Yura E ，Morishita Y ，Kondo M ，Tsunekawa S ，Nakayama T ，Nakamura J ，Kamiya H ... -  《-》

Point-of-care nerve conduction device predicts the severity of diabetic polyneuropathy: A quantitative, but easy-to-use, prediction model.

Kamiya H ，Shibata Y ，Himeno T ，Tani H ，Nakayama T ，Murotani K ，Hirai N ，Kawai M ，Asada-Yamada Y ，Asano-Hayami E ，Nakai-Shimoda H ，Yamada Y ，Ishikawa T ，Morishita Y ，Kondo M ，Tsunekawa S ，Kato Y ，Baba M ，Nakamura J ... -  《-》

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

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

Kawai M ，Himeno T ，Shibata Y ，Hirai N ，Asada-Yamada Y ，Asano-Hayami E ，Ejima Y ，Kasagi R ，Nagao E ，Sugiura-Roth Y ，Nakai-Shimoda H ，Nakayama T ，Yamada Y ，Ishikawa T ，Morishita Y ，Kondo M ，Tsunekawa S ，Kato Y ，Nakamura J ，Kamiya H ... -  《-》

Difference in normal limit values of nerve conduction parameters between Westerners and Japanese people might need to be considered when diagnosing diabetic polyneuropathy using a Point-of-Care Sural Nerve Conduction Device (NC-stat®/DPNCheck™).

Studies on a novel point-of-care device for nerve conduction study called DPNCheck have been limited to Westerners. We aimed to clarify Japanese normal limits of nerve action potential amplitude (Amp) and conduction velocity by DPNCheck (investigation I), and the validity of DPNCheck to identify diabetic symmetric sensorimotor polyneuropathy (DSPN; investigation II). For investigation I, 463 non-neuropathic Japanese participants underwent DPNCheck examinations. Regression formulas calculating the normal limits of Amp and conduction velocity (Japanese regression formulas [JRF]) were determined by quantile regression and then compared with regression formulas of individuals from the USA (USRF). For investigation II, in 92 Japanese diabetes patients, 'probable DSPN' was diagnosed and nerve conduction abnormalities (NCA1: one or more abnormalities, and NCA2: two abnormalities in Amp and conduction velocity) were determined. Validity of NCAs to identify 'probable DSPN' was evaluated by determining sensitivity, specificity, reproducibility (kappa-coefficient) and the area under the curve of receiver operating characteristic curves. For investigation I, JRF was different from USRF, and normal limits by JRF were higher than that of USRF. The prevalence of Amp abnormality calculated by JRF was significantly higher than that of USRF. For investigation II, the sensitivity, specificity and reproducibility of NCA1 and NCA2 judged from JRF were 85%, 86% and 0.57, and 43%, 100% and 0.56, respectively. These values of JRF were higher than those of USRF. The area under the curve of JRF (0.89) was larger than USRF (0.82). A significant difference in the normal limits of nerve conduction parameters by DPNCheck between Japanese and USA individuals was suggested. Validity to identify DSPN of NCAs might improve by changing the judgment criteria from USRF to JRF.

Hirayasu K ，Sasaki H ，Kishimoto S ，Kurisu S ，Noda K ，Ogawa K ，Tanaka H ，Sakakibara Y ，Matsuno S ，Furuta H ，Arita M ，Naka K ，Nanjo K ... -  《-》

Assessment of diabetic neuropathy using a point-of-care nerve conduction device shows significant associations with the LDIFLARE method and clinical neuropathy scoring.

Accurate assessment of diabetes polyneuropathy (DPN) is important in the prevention of foot ulcerations and amputations. Simple screening methods including the 10 g monofilament and the 128-Hz tuning fork are not sensitive enough nor intended for detection of early neuropathy, while more confirmatory tests such as nerve conduction studies are not universally available. We evaluated a rapid, low-cost, point-of-care nerve conduction device (POCD; NC-stat®|DPNCheck™) for the assessment of DPN and compared it with the LDIFLARE technique-an established method for early detection of small fibre dysfunction. A total of 162 patients with diabetes (DM) and 80 healthy controls (HC) were recruited. Based on the 10-point Neuropathy Disability Score (NDS), DPN was categorized into none (<2), mild (3-5) moderate (6-7), and severe (8-10). The LDIFLARE was performed in all patients according to previously described methodology. The associations between POCD outcomes and the LDIFLARE within the NDS categories were evaluated using regression analysis. In HC and DM, SNCV measured with the POCD correlated significantly with the LDIFLARE technique (r < 0.90 and r = 0.78, respectively) as did SNAP (r = 0.88 and r = 0.73, respectively); in addition, significance was found in all categories of DPN (r = 0.64 to 0.84; p= ≤ 0.03). ROC curves within each category of DPN showed that the POCD was sensitive in the assessment of DPN. We report highly significant linear relationships between the POCD with both comparators-the LDIFLARE technique and clinical neuropathy scores. Thus, the NC-stat|DPNCheck™ system appears to be an excellent adjunctive diagnostic tool for diagnosing DPN in the clinical setting.

Sharma S ，Vas PR ，Rayman G 《-》