Patterns of Nerve Conduction Abnormalities in Patients with Type 2 Diabetes Mellitus According to the Clinical Phenotype Determined by the Current Perception Threshold

Abstract

BackgroundClinical manifestations of diabetic peripheral neuropathy (DPN) vary along the course of nerve damage. Nerve conduction studies (NCS) have been suggested as a way to confirm diagnoses of DPN, but the results have limited utility for evaluating clinical phenotypes. The current perception threshold (CPT) is a complementary method for diagnosing DPN and assessing DPN symptoms. We compared NCS variables according to clinical phenotypes determined by CPT measurements.MethodsWe retrospectively enrolled patients with type 2 diabetes mellitus who underwent both NCS and CPT tests using a neurometer. CPT grades were used to determine the clinical phenotypes of DPN: normoesthesia (0 to 1.66), hyperesthesia (1.67 to 6.62), and hypoesthesia/anesthesia (6.63 to 12.0). The Michigan Neuropathy Screening Instrument (MNSI) was used to determine a subjective symptom score. DPN was diagnosed based on both patient symptoms (MNSI score ≥3) and abnormal NCS results.ResultsA total of 202 patients (117 men and 85 women) were included in the final analysis. The average age was 62.6 years, and 71 patients (35.1%) were diagnosed with DPN. The CPT variables correlated with MNSI scores and NCS variables in patients with diabetes. Linear regression analyses indicated that hypoesthesia was associated with significantly lower summed velocities and sural amplitudes and velocities, and higher summed latencies, than normoesthesia. Sural amplitude was significantly lower in patients with hyperesthesia than in patients with normoesthesia.ConclusionNCS variables differed among patients with diabetes according to clinical phenotypes based on CPT and decreased sural nerve velocities was associated with hyperesthesia.

The relationship between exacerbated diabetic peripheral neuropathy and metformin treatment in type 2 diabetes mellitus

“…Electrophysiological nerve conduction studies (NCS) can confirm that the diagnosis of DPN and the sural nerve is the most applicable to correlating with the severity of DPN 22 . However, NCS does not generally distinguish early changes of neuronal damage and some DPN patients give negative results in the clinical assessment 23 . Our study intends to distinguish the serum level of cobalamin, methylmalonic acid and homocysteine changes in Metformin-treated diabetics (MTD) and to evaluate the connection between the severity of DPN and the long-term utilization of metformin.…”

Association between Sleep Quality and Painless Diabetic Peripheral Neuropathy Assessed by Current Perception Threshold in Type 2 Diabetes Mellitus

“…Still, although NCS is recommended as the test to confirm DPN, quantitative sensory test (QST) like CPT also has been widely used as a method of assessing DPN [43][44][45][46]. Furthermore, since CPT assesses the function of three major types of sensory fibers by using different impulse frequencies, it has been used as a tool of early detection of DPN including its painless type, which is required in current study design [47][48][49][50]. We also used CPT subscale tests which were not performed in the previous studies on DPN and poor sleep quality.…”

γ-Linolenic Acid versus α-Lipoic Acid for Treating Painful Diabetic Neuropathy in Adults: A 12-Week, Double-Placebo, Randomized, Noninferiority Trial

“…After completion of the MNSIQ, trained technicians examined the subjects for deformities, dry skin, callus, infections, ulcerations, vibration senses on the interphalangeal joints of both great toes, muscle strength reflexes using a hammer at the Achilles tendon on both ankles, and the monofilament test at the dorsum of both great toes [22]. The CPT was assessed as previously described [23]. Briefly, small electrodes were taped to the test sites (index fingers and great toes) and the responses to three different stimuli (2,000, 250, and 5 Hz) were recorded with increasing currents at each frequency.…”