To investigate risk factors for diabetic peripheral polyneuropathy and their correlation with the quantified severity of nerve dysfunction in patients with diabetes mellitus (DM).
A total of 187 diabetic patients with clinically suspected polyneuropathy (PN) were subclassified into 2 groups according to electrodiagnostic testing: a DM-PN group of 153 diabetic patients without electrophysiological abnormality and a DM+PN group of 34 diabetic patients with polyneuropathy. For all patients, age, sex, height, weight, duration of DM, and plasma glycosylated hemoglobin (HbA1c) level were comparatively investigated. A composite score was introduced to quantitatively analyze the results of the nerve conduction studies. Logistic regression analysis and multiple regression analysis were used to evaluate correlations between significant risk factors and severity of diabetic polyneuropathy.
The DM+PN group showed a significantly higher HbA1c level and composite score, as compared with the DM-PN group. Increased HbA1c level and old age were significant predictive factors for polyneuropathy in diabetic patients (odds ratio=5.233 and 4.745, respectively). In the multiple linear regression model, HbA1c and age showed a significant positive association with composite score, in order (β=1.560 and 0.253, respectively).
Increased HbA1c level indicative of a state of chronic hyperglycemia was a risk factor for polyneuropathy in diabetic patients and a quantitative measure of its severity.
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To demonstrate the prevalence and characteristics of subclinical ulnar neuropathy at the elbow in diabetic patients.
One hundred and five patients with diabetes mellitus were recruited for the study of ulnar nerve conduction analysis. Clinical and demographic characteristics were assessed. Electrodiagnosis of ulnar neuropathy at the elbow was based on the criteria of the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM1 and AANEM2). The inching test of the ulnar motor nerve was additionally performed to localize the lesion.
The duration of diabetes, the existence of diabetic polyneuropathy (DPN) symptoms, the duration of symptoms, and HbA1C showed significantly larger values in the DPN group (p<0.05). Ulnar neuropathy at the elbow was more common in the DPN group. There was a statistically significant difference in the number of cases that met the three diagnostic criteria between the no DPN group and the DPN group. The most common location for ulnar mononeuropathy at the elbow was the retrocondylar groove.
Ulnar neuropathy at the elbow is more common in patients with DPN. If the conduction velocities of both the elbow and forearm segments are decreased to less than 50 m/s, it may be useful to apply the AANEM2 criteria and inching test to diagnose ulnar neuropathy.
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To understand the quantitative correlation between the clinical severity and physical examinations along with the electrodiagnostic findings by subjects with carpal tunnel syndrome (CTS) and also the influence of diabetic polyneuropathy (DPN) on physical examinations by subjects with CTS.
Among 200 patients suffering from hand tingling sensations, 68 patients were diagnosed with CTS on at least one hand by nerve conduction tests. Therefore, the Phalen test (PT), hand elevation test (HET), Tinel sign (TS) results were recorded on both hands. The physical examination grades were compared with the electrophysiological CTS grades in 126 hands of 68 patients. Also the comorbidity effect of DPN to CTS was evaluated. For the evaluation of the severity correlations between CTS, PT, HET, and TS, the Spearman analysis was used. An attempt was started to create a formula which could depict the electrophysiological severity of CTS.
Out of the 68 tested subjects, 31 were diagnosed with both DPN and CTS, and 37 with CTS only. Both PT and HET correlated well with the severity of CTS where the correlation of PT was higher than that of HET. The formula were the motor distal latency (MDL)=(72.4-PT)/5.3 and MDL=(76-HET)/7.2. Both PT and HET showed in the presence of DPN a relatively higher relation with CTS without significance.
PT and HET would be useful screening tools for the diagnosis and treatment of CTS as the grade of PT and HET present the severity of CTS well. During this study, a formula was created expecting the severity of nerve conduction study with PT and HET through the time domain value of physical examinations.
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Objective: To evaluate the usefulness of the sural/superficial radial sensory nerve action potential amplitude ratio (SRAR) in the electrodiagnosis of diabetic polyneuropathy.
Method: Nerve conduction study was performed in 80 diabetic patients and 31 normal adults. Standard nerve conduction studies were performed. Sural nerve response was recorded with the active electrode on the posterosuperior margin of the lateral malleolus and stimulation 14 cm proximally. Superficial radial nerve response was recorded with the active on the snuffbox and stimulation 10 cm proximally. Baseline-to-peak sensory nerve action potential (SNAP) amplitudes were measured, and SRAR were obtained. The diabetic group was subdivided into an electrophysiologically normal group (DMNL, n=32) and neuro-
pathy group (DMPN, n=48). SRAR was compared among the control (NORM, n=31), DMNL and DMPN groups.
Results: SRAR was 0.344 in NORM, 0.314 in DMNL and 0.145 in DMPN, respectively. SRAR showed 77.1% sensitivity and 93.8% specificity. Sural SNAP amplitude sensitivity was 85.4% and specificity, 88.7%.
Conclusion: The relatively high specificity of SRAR indicates its usefulness in the diagnosis of diabetic polyneuropathy. However, as the superficial radial sensory SNAP amplitude decreased significantly in the diabetic groups compared to control, the SRAR is not superior to the sural SNAP amplitude in the diagnosis of diabetic polyneuropathy. (J Korean Acad Rehab Med 2002; 26: 147-151)
Objective: To acknowledge whether flexion or extension of wrist joint produces any changes in median nerve conduction of the diabetes with or without polyneuropathy.
Method: With thirty healthy adults selected as control, 33 diabetes with polyneuropathy (Group I) and 21 diabetes without polyneuropathy (Group II) were studied. Before the study, the wrist joint was positioned in flexion or extension for 5 minutes. The variables used for the statistic analysis were mean changes of latencies and amplitudes in the median motor and sensory responses in neutral, flexed, and extended position.
Results: After wrist flexion or extension, there was no significant difference in the mean change of latencies and trans-carpal conduction velocities between Group I and Group II in the median motor and sensory nerve conduction studies, and in the mean change of amplitudes between the two groups in the median motor nerve study. But, there was significant difference in the mean change of amplitude between Group I and Group II in the median sensory nerve study after wrist extension.
Conclusion: We conclude that the change of amplitude in median nerve conduction study in different wrist position may be helpful to detect carpal tunnel syndrome with diabetic polyneuropathy in its early stage.
Objective: To find simple screening method for assessment of patients with diabetic neuropathy by use of brief questionnaire, scored physical examination including vibration perception threshold, and mixed median conduction study.
Method: Subjects were 24 patients with diabetes mellitus. Conventional nerve conduction study was performed in 24 patients and the patients were divided into two groups: 11 patients with polyneuropathy; 13 patients of normal findings. The questionnaires were given for evaluation of sensory function in all the subjects. The questionnaires were followed by physical examination including two point discrimination, vibration perception threshold by using biothesiometer, 10 gram filament test, pin prick test, DTR check, and muscle strength test. Abnormality was determined by the number of positive responses or abnormal clinical findings. Finally, we recorded the conduction velocity and amplitude of median mixed nerve and compared these parameters to values of 20 normal adults.
Results: The questionnaire and physical exam scores were higher in patients with polyneuropathy (p＜0.01). The patients with polyneuropathy showed higher vibration perception threshold values (p＜0.01) and slower conduction velocity and smaller amplitude of median mixed nerve (p＜0.05). In correlation with conventional nerve conduction study, the median mixed nerve conduction velocity had higher kappa value than amplitude in screening for diabetic polyneuropathy.
Conclusion: We suggest the questionnaires, scored physical examination, vibration perception threshold, and median mixed nerve conduction velocity to be a simple screening method for assessment of patients with diabetic plyneuropathy.
Objective: To investigate the regional differences of skin blood flow and to evaluate the effects of foot temperature on the severity of neuropathic pain and to predict the development of plantar foot ulceration by measuring of the temperature variations on the plantar surface of feet in the diabetic patients.
Method: We measured the temperature variations on plantar surface of the feet in controls (n=18) and diabetic patients with(n=20) or without(n=23) polyneuropathy. The surface temperature from the 3rd metatarsal head(MTH), greater toe(GT), heel, medial and lateral longitudinal arch(LA) was measured by Digital Infrared Thermographic Imaging(DITI).
Results: The mean foot temperature of diabetic patients with polyneuropathy was significantly increased compared to controls or diabetic patients without polyneuropathy(p＜0.001). The surface temperature readings of the GT, medial LA and the 3rd MTH tended to be increased in controls and patients with polyneuropathy. The mean plantar surface temperature was significantly increased according to the duration of diabetes mellitus(DM)(p＜0.05).
Conclusion: The results suggest that DITI provides a diagnostic modality in the prediction of neuropathic foot and increased risks of foot ulcer development in the diabetic patients.
Objective: To evaluate the usefulness of cutaneous silent period(CSP) in assessing the pain sensory function mediated by the Aδ fiber in diabetic polyneuropathy and to define the proper CSP parameter and method.
Method: We studied 18 diabetic polyneuropathy patients and 20 age-matched healthy subjects. CSPs were recorded in the abductor pollicis brevis muscle and soleus muscle with the surface electrodes and a painful electrical stimulation was given to the mixed nerves(median and tibial nerve) and cutaneous nerve(ulnar and superficial peroneal nerve). Onset latency, end point and duration of CSP were compared between two groups. CSP parameters correlated with the motor and sensory nerve conduction parameters in diabetic polyneuropathy patients.
Results: CSP onset latency and end point were significantly delayed in diabetic polyneuropathy patients for both mixed nerve and cutaneous nerve stimulations. There was no difference in CSP duration between two groups. CSP onset latency was shortend and duration was prolonged in mixed nerve stimulation due to an antidromic collision, which showed a cutaneous nerve stimulation as the propor method. There was no correlation between the CSP parameters and motor and sensory nerve conduction parameters. In 3 cases, the CSPs were unable to the evoked despite the sensory nerve action potential was normally evoked. This suggests that the CSP would give an information about the Aδ fiber function than the large myelinated fiber.
Conclusion: This study indicates that the CSP is a useful supportive electrophysiologic study to assess the Aδ fiber function in diabetic polyneuropathy. The CSP onset latency and cutaneous nerve stimulation are the useful parameter and method for the CSP.
Residual latency is the difference between the expected and measured terminal latencies in nerve conduction study. The main contributors to the residual latency are the nerve tapering in the hand and fingers and the neuromuscular delay. We measured median motor and sensory residual latencies in the controls and in patients with diabetes mellitus(DM) to establish the normal values, to evaluate the diagnostic value of the residual latency in diabetic polyneuropathy. we studied 50 healthy controls and 100 diabetic patients with or without polyneuropathy.
The normal residual latency values were 1.42⁑0.41 msec(mean⁑SD) in motor part and 0.44⁑0.20 msec in sensory part of median nerve. The standard deviation of residual latency in median motor nerve was decreased by 12% as compared with that of distal latency in the patient with diabetic polyneuropathy. Duration of DM and age were not related to the residual latency of median nerve.
The results suggest that the residual latency of median motor nerve provides a narrower normal range in the diagnosis of diabetic polyneuropathy irrespective of duration of DM or age.
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