To investigate the analgesic effect of transcranial direct current stimulation (tDCS) over the primary motor (M1), dorsolateral prefrontal cortex (DLPFC), and sham tDCS in patients with painful diabetic polyneuropathy (PDPN).
Patients with PDPN (n=60) were divided randomly into the three groups (n=20 per group). Each group received anodal tDCS with the anode centered over the left M1, DLPFC, or sham stimulation for 20 minutes at intensity of 2 mA for 5 consecutive days. A blinded physician rated the patients' pain using a visual analog scale (VAS), Clinical Global Impression (CGI) score, anxiety score, sleep quality, Beck Depression Inventory (BDI), and the pain threshold (PT) to pressure.
After the tDCS sessions, the M1 group showed a significantly greater reduction in VAS for pain and PT versus the sham and DLPFC groups (p<0.001). The reduction in VAS for pain was sustained after 2 and 4 weeks of follow-up in the M1 group compared with the sham group (p<0.001, p=0.007). Significant differences were observed among the three groups over time in VAS for pain (p<0.001), CGI score (p=0.01), and PT (p<0.001). No significant difference was observed among the groups in sleep quality, anxiety score, or BDI score immediately after tDCS.
Five daily sessions of tDCS over the M1 can produce immediate pain relief, and relief 2- and 4-week in duration in patients with PDPN. Our findings provide the first evidence of a beneficial effect of tDCS on PDPN.
Citations
Method: The subjects were 26 patients with asymptomatic diabetic neuropathy and 40 healthy adults as control group. All subjects underwent electrodiagnostic evaluation of the following motor nerves: median, ulnar, tibial, and peroneal. Sensory nerves included: median, ulnar, radial, superficial peroneal, sural, lateral dorsal cutaneous branch of the sural nerve (LDSN) and medial plantar. And other studies were the sural/radial amplitude ratio, LDSN/sural amplitude ratio, peroneal and tibial F-responses, and H-reflex recorded from the soleus muscle. The frequency of abnormal parameters in the patients with asymptomatic diabetic neuropathy was obtained by comparison with the normative limits obtained from the control group.
Results: The most frequent abnormal electrodiagnostic parameters were the LDSN onset latency and the amplitude ratio of LDSN/sural (84.6%, respectively) followed by the LDSN peak latency, LDSN amplitude, and medial plantar onset and peak latency (80.8%, respectively).
Conclusion: We concluded that the LDSN and medial plantar nerve conduction studies are useful for early detection of neuropathy in diabetes mellitus. (J Korean Acad Rehab Med 2003; 27: 75-79)
Objective: To assess the axonopathy and demyelination neuropathy according to the electrophysiologic severity in diabetic neuropathy.
Method: Electrophysiologic data of 246 patients who had been diagnosed with diabetic neuropathy was obtained and classified into suspected, possible, and definite groups by the criteria of our laboratory. Nerve conduction study was performed in the median, ulnar motor and sensory nerves, peroneal and tibial motor nerves, and sural nerve. Statistics were done with the results from the median motor and sensory, tibial motor and sural nerves. According to the severity of diabetic neuropathy, correlation and Chi-square analysis between amplitudes and latencies were performed.
Results: Frequencies of diabetic neuropathy according to
electrophysiologic severity were as follows: 24 cases of suspected, 141 cases of possible, and 81 cases of definite neuropathy. The correlation ratios between amplitude and latency were 0.41∼0.79 (p＜0.05) in the definite group of all the nerves examined, and below 0.3 in the suspected and possible groups. By Chi-square analysis, amplitude reduction was the predominant finding in the suspected and possible groups.
Conclusion: In the early stage of diabetic neuropathy, axonopathy might be the preceding pathogenesis, while with progression of diabetic neuropathy, axonopathy and demyelination may coexist. (J Korean Acad Rehab Med 2002; 26: 50-54)
Objective: The purpose of this study is to find out whether amplitude ratio and area ratio have correlation with nerve conduction velocity in the diabetes mellitus patients.
Method: Median and deep peroneal motor nerve conduction study was performed in thirty-five normal control group and sixty diabetes mellitus patients group. The motor conduction velocity, amplitude ratio, and area ratio of the compound muscle action potential (CMAP) were measured. The experimental subjects were divided into 6 subgroups (in median nerve: M1, M2, M3, in peroneal nerve: P1, P2, P3) according to the median value of conduction velocity of each nerve; group M1 (n=35) and P1 (n=30): normal control group, group M2 (n=25) and P2 (n=30): below the median value of motor nerve conduction velocity in diabetes mellitus patients, group M3 (n=23) and P3 (n=29): above the median value of motor nerve conduction velocity in diabetes mellitus patients.
Results: There was no significant difference of area ratio between the each subgroups in both median and peroneal nerves. There was a significant difference of amplitude ratio between the M1 and M2 subgroups. There was a significant difference of amplitude ratio between the P1 and P2, P3 subgroups.
Conclusion: According to above results, the decrease of amplitude of compound muscle action potential along with the decrease of conduction velocity seems to be helpful in the electrophysiologic diagnosis of diabetic neuropathy.
Objective: Sural nerve conduction study is known to be one of the sensitive tests for detecting neuropathies. In peripheral neuropathy, the distal sural nerve, lateral dorsal cutaneous branch of sural nerve (LDCBSN), may be more easily affected than proximal portion of the sural nerve. To evaluate the clinical application of LDCBSN conduction study and amplitude comparison between sural nerve and LDCBSN in peripheral neuropathy.
Method: Antidromic conduction studies were performed for sural nerve and LDCBSN and amplitude between two nerve responses were obtained in 30 controls (mean age, 46) and 30 patients with diabetic neuropathy (mean age, 54), but obtainable sural sensory response. The active recording electrodes were placed were placed over the dorsolateral surface at the midpoint of the fifth metatarsal for LDCBSN and posterior aspect of lateral malleolus for sural nerve. The stimulating electrodes were placed 12 cm proximal to the active electrodes in both nerves.
Results: LDCBSN response was obtainable in all controls and not obtainable in 7 diabetic patients in whom the amplitude of sural response was less than 5 uV. The amplitude of LDCBSN to sural nerve was approximately 35% in controls and 22% in diabetic patients, which was statistically significant (p=0.00).
Conclusion: LDCBSN conduction study is sensitive test to detect peripheral neuropathies and amplitude ratio of LDCBSN to sural nerve can be used in the evaluation of peripheral neuropathies.
Objective: The purpose of this study was to evaluate therapeutic effect of local steroid injection in carpal tunnel syndrome, and to make a comparison between therapeutic effect in patients with and without diabetic neuropathy.
Method: 30 patients (40 hands) with carpal tunnel syndrome diagnosed clinically and electrophysiologically were injected with 40mg of methylprednisone. Patients were evaluated with the visual analogue scale after 4 weeks and 8 weeks. According to the therapeutic responses, the patients were grouped into: excellent; good; poor; failed; recurrent.
Results: After 4 weeks, symptom relief was noted in the 95% of all cases: 100% of the patients without diabetic neuropathy; 82% of the patients with diabetic neuropathy. After 8 weeks, symptom relief was noted in the 82.5% of all cases: 86% of the patients without diabetic neuropathy; 73% of the patients with diabetic neuropathy. There was no statistically significant difference between the patients with and without diabetic neuropathy (p＞0.05).
Conclusion: We concluded that local steroid injection in carpal tunnel syndrome was an effective therapeutic modality for a short term and local steroid injection in the carpal tunnel syndrome with diabetic neuropathy diagnosed by palmar test also had a good effect.
Objective: To investigate the reliability of distoproximal latency ratio of median sensory nerve as a diagnostic criterion of carpal tunnel syndrome (CTS) in patients with diabetic polyneuropathy.
Subject: Electrophysiologic study was performed in 264 hands of 208 patients with diabetes. Forty eight hands (24 subjects) without diabetes mellitus or CTS were included as a normal control group. Another 48 hands having CTS without diabetes mellitus were also included as a CTS control group.
Method: Clinical and electrophysiologic findings were included to detect carpal tunnel syndrome in patients with diabetic neuropathy. Sensitivity and specificity of various electrodiagnostic parameters to confirm clinical CTS were obtained.
Results: Diabetic neuropathy was diagnosed in 66.3%, and median neuropathy was diagnosed in 52.7%. CTS was found in 32.2% as determined by the distoproximal latency ratio. The sensitivity of distoproximal latency ratio as a diagnostic tool for CTS was the highest (95.1%) and the specificity was the second highest (51.3%) among 5 different electrodiagnostic criteria of CTS.
Conclusion: The results suggest that distoproximal latency ratio is an important parameter with high sensitivity in determining CTS in the patients with diabetic polyneuropathy.
Objective: The purpose of this study was to determine the relationship of abnormal parameters in commonly tested peripheral nerves and clinical findings in diabetic neuropathy.
Method: Parameters in tested peripheral nerves are all 18 as follows; Distal latency and amplitude of median motor, median sensory, ulnar motor, ulnar sensory, tibial motor, peroneal motor, and sural sensory (14) plus conduction velocity of median motor, ulnar motor, peroneal motor, and tibial motor (4). Person who had at least one abnormal parameter out of 18 parameters counted as abnormal group and then it was divided 3 groups depending on numbers of abnormal parameter as follows; one to two abnormal parameters as mild group, three to five as moderate group, and more than 6 as severe group.
Results: The factors which were correlated with number of abnormal parameters on nerve conduction study (NCS) were 1) duration of diabetes mellitus and 2) age of patients but not the level of HbA1c (p＜0.05). The involved nerves in the order of frequency were sural sensory (49.7%), peroneal motor (43.2%), median sensory (32.7%), ulnar sensory (31.2%), median motor (29.6%), and ulnar motor (23.1%). In persons having mild grade on NCS, amplitude of sensory nerve action potential (SNAP) was more frequently involved than distal latency of SNAP. Among the parameters, amplitude of median compound muscle action potential (CMAP), amplitude of ulnar CMAP, distal latency of ulnar SNAP and the amplitude and distal latency of tibial CMAP seemed to be less affected in diabetic neuropathy.
Conclusion: The amplitude of SNAP seemed to be valuable parameter in detection of early diabetic neuropathy.
Objective: To determinate the reference values of residual latencies of motor nerves and to evaluate the early diagnostic value of residual latency.
Method: The subjects were 129 diabetes mellitus patients and 60 controls with no known neurological disorders. The patients were divided into two groups based on the conventional nerve conduction study: Group 1, 75 patients without neuropathy; Group 2, 54 patients with neuropathy. The group 2 patients were subdivided into 4 sub- groups on the basis of conduction velocity and residual latency of the median nerve. Residual latencies were measured in all subjects and glycosylated hemoglobin percentages (HbA1c) were measured in the diabetes patients. In group 2, each nerve conduction parameter was correlated with the duration of diabetes and HbA1c. The duration of diabetes, HbA1c, and amplitude of median nerve response were compared between the subgroups of group 2 patients.
Results: Motor residual latencies obtained from the controls were 1.93⁑0.28 msec, 1.53⁑0.24 msec, 2.46⁑0.43 msec, 2.21⁑0.53 msec in median, ulnar, deep peroneal and posterior tibial nerves, respectively. In group 1, motor residual latencies of median & deep peroneal nerves were significantly delayed compared with those of the controls. In group 2, motor residual latencies of median, ulnar, deep peroneal and posterior tibial nerves were significantly delayed more than those of the controls and group 1.
In group 2, increased HbA1c correlated to the decreased conduction velocities of median, deep peroneal, posterior tibial nerves but not to the residual latencies.
In the subgroup of group 2 (2-D), the nerve involved more distally showing lower compound muscle action potential and higher HbA1c.
Conclusion: Residual latency measurement can be a useful diagnostic method for the early detection of diabetic neuropathy.
Objective: This study aims the electrophysiological documentation of possible neurological abnormalities in diabetic patients with or without neuropathy symptoms.
Method: Forty five diabetic patients, 15 male and 30 female, were included in this study. They were divided into symptomatic and asymptomatic groups and received various electrophysiologic studies including a nerve conduction study, F-wave study and median and tibial SSEP study. The clinical parameters were the clinical symptom and sign of neuropathy, disease duration, complications, HbA1c, and fasting blood sugar. Statistical significances of the parameters were observed between symptomatic and asymptomatic groups.
Results: The most sensitive electrophysiologic parameter was the tibial SSEP. For the documentation of diabetic neuropathy, the electrophysiologic study of posterior tibial, median, superficial peroneal and sural nerves were most useful. F-wave study did not reflect the early involvement of proximal nerve segment in diabetic patients.
Conclusion: Multimodal neurophysiological approaches including a tibial SSEP study rather than the conventional nerve conduction studies can depict a broader and more complete map of the possible abnormalities of diabetic neuropathy.
Objective: The purposes of this study were to obtain the reference values of latency and amplitude of the medial plantar sensory nerve action potential(SNAP) in normal controls and to evaluate the diagnostic sensitivity of medial plantar sensory nerve conduction study(NCS) in diabetic neuropathy.
Method: Thirty healthy controls(mean age, 48.7 years; range, 38∼59 years) and 33 diabetic patients(mean age, 50.8 years; range, 37∼64 years) were included in this study. The inclusion criteria for diabetic patients were subjects with the normal peroneal and tibial compound muscle action potentials, obtainable sural SNAPs and intact pressure-perception to Semmes-Weinstein monofilamentⰒ 5.07.
Results: The medial plantar sensory nerve action potentials were obtainable in all control subjects and the reference values of onset latency and peak to peak amplitude were 4.29⁑0.49 msec and 3.1⁑1.34 ㄍV, respectively.
All 33 diabetic patients showed the normal latency and 3 of them showed the low amplitude in sural SNAPs. The medial plantar SNAPs were obtainable in 24 diabetic patients. Among 9 patients with unobtainable medial plantar SNAPs, 6 showed the normal sural SNAPs and 3 showed the low sural SNAPs. The sensitivities of medial plantar SNAPs to sural nerve and sural SNAPs to medial plantar sensory nerve were 100%(3/3) and 27.3%(3/11) respectively.
Conclusion: We concluded that medial plantar sensory NCS was more valuable in the early diagnosis of diabetic neuropathy than the sural NCS and Semmes-Weinstein monofilamentⰒ(North Coast Medical Inc, USA).
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