OBJECTIVEWe aimed to determine the corneal confocal microscopy (CCM) parameter that best identifies diabetic sensorimotor polyneuropathy (DSP) in type 1 diabetes and to describe its performance characteristics.RESEARCH DESIGN AND METHODSConcurrent with clinical and electrophysiological examination for classification of DSP, CCM was performed on 89 type 1 diabetic and 64 healthy subjects to determine corneal nerve fiber length (CNFL), density, tortuosity, and branch density. Area under the curve (AUC) and optimal thresholds for DSP identification in those with diabetes were determined by receiver operating characteristic (ROC) curve analysis.RESULTSDSP was present in 33 (37%) subjects. With the exception of tortuosity, CCM parameters were significantly lower in DSP case subjects. In ROC curve analysis, AUC was greatest for CNFL (0.88) compared with fiber density (0.84, P = 0.0001), branch density (0.73, P < 0.0001), and tortuosity (0.55, P < 0.0001). The threshold value that optimized sensitivity and specificity for ruling in DSP was a CNFL of ≤14.0 mm/mm2 (sensitivity 85%, specificity 84%), associated with positive and negative likelihood ratios of 5.3 and 0.18. An alternate approach that used separate threshold values maximized sensitivity (threshold value ≥15.8 mm/mm2, sensitivity 91%, negative likelihood ratio 0.16) and specificity (≤11.5 mm/mm2, specificity 93%, positive likelihood ratio 8.5).CONCLUSIONSAmong CCM parameters, CNFL best discriminated DSP cases from control subjects. A single threshold offers clinically acceptable operating characteristics, although a strategy that uses separate thresholds to respectively rule in and rule out DSP has excellent performance while minimizing unclassified subjects. We hypothesize that values between these thresholds indicate incipient nerve injury that represents those individuals at future neuropathy risk.
Development of corneal confocal microscopy may need to focus on the measurement of corneal nerve fibre length, as it appears to have superior reliability in comparison with other parameters, and as evidence exists for its potential as a clinical biomarker of early diabetic sensorimotor polyneuropathy.
OBJECTIVEPeripheral nerve imaging by portable ultrasound (US) may serve as a noninvasive and lower-cost alternative to nerve conduction studies (NCS) for diagnosis and staging of diabetic sensorimotor polyneuropathy (DSP). We aimed to examine the association between the size of the posterior tibial nerve (PTN) and the presence and severity of DSP.RESEARCH DESIGN AND METHODSWe performed a cross-sectional study of 98 consecutive diabetic patients classified by NCS as subjects with DSP or control subjects. Severity was determined using the Toronto Clinical Neuropathy Score. A masked expert sonographer measured the cross-sectional area (CSA) of the PTN at 1, 3, and 5 cm proximal to the medial malleolus.RESULTSFifty-five patients had DSP. The mean CSA of the PTN in DSP compared with control subjects at distances of 1 (23.03 vs. 17.72 mm2; P = 0.004), 3 (22.59 vs. 17.69 mm2; P < 0.0001), and 5 cm (22.05 vs. 17.25 mm2; P = 0.0005) proximal to the medial malleolus was significantly larger. Although the area under the curve (AUC) for CSA measurements at all three anatomical levels was similar, the CSA measured at 3 cm above the medial malleolus had an optimal threshold value for identification of DSP (19.01 mm2) with a sensitivity of 0.69 and a specificity of 0.77 by AUC analysis.CONCLUSIONSThis large study of diabetic patients confirms that the CSA of the PTN is larger in patients with DSP than in control subjects, and US is a promising point-of-care screening tool for DSP.
OBJECTIVE -The diagnosis of diabetic sensorimotor polyneuropathy using objective electrophysiological tests is hindered by limited access to the specialized laboratories and technicians that perform and interpret them. We evaluated the performance characteristics of a novel portable and automated point-of-care nerve conduction study device, which can be operated by nontechnical personnel, and compared it with conventional nerve conduction studies performed in a specialist setting.RESEARCH DESIGN AND METHODS -Seventy-two consecutive patients with diabetes (8 type 1, 64 type 2) from a diabetes and a neuropathy outpatient clinic were evaluated concurrently with conventional nerve conduction studies (the reference standard) and the pointof-care device for sural nerve function (sural nerve amplitude potentials in microvolts [V]).RESULTS -Sural nerve amplitude potentials measured by the point-of-care device shared very strong correlation with the reference standard (Spearman's correlation coefficient 0.95, P Ͻ 0.001). The Bland and Altman method yielded agreement despite a small systematic underestimation by the point-of-care device of 1.2 Ϯ 3.4 V. Despite this small systematic bias, the sensitivity and specificity of normal and abnormal sural nerve amplitude potentials measured by the point-of-care device for the detection of diabetic sensorimotor polyneuropathy defined by standard clinical and electrophysiological criteria were 92 and 82%, respectively.CONCLUSIONS -A novel point-of-care device has excellent diagnostic accuracy for detecting electrophysiological abnormality in the sural nerve of patients who have diabetes. This automated device represents an alternative to conventional nerve conduction studies for the diagnosis of diabetic sensorimotor polyneuropathy. Diabetes Care 29:2023-2027, 2006D iabetic sensorimotor polyneuropathy is by far the most common neurological complication of diabetes, as it imparts a lifetime risk of up to 50% (1,2). It represents an insidious and progressive process that begins with a long asymptomatic stage during which identification and management is challenging (3,4). It is important to identify neuropathy early in the course of its development, even in the asymptomatic stages, because the disease process predictably progresses to produce extreme morbidity (2,5) and health care costs (6,7) that arise from pain, imbalance, foot deformity, and the late-stage consequences of infection, ulceration, and amputation. Many of these consequences are thought to be preventable if appropriate clinical management (the combination of early identification, intensification of glycemic control, and surveillance for foot complications) is instituted (8 -10).Clinical practice guidelines for the care of people who have diabetes recommend annual screening for diabetic sensorimotor polyneuropathy using simple tools such as the 10-g Semmes-Weinstein monofilament or the 128-Hz vibration tuning fork (11,12). These simple tests predict the presence of neuropathy defined by electrophysiological criteria (n...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.