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To examine the usefulness of the second lumbrical-interosseous (2L-INT) distal motor latency (DML) comparison test in localizing median neuropathy to the wrist in patients with absent median sensory and motor response in routine nerve conduction studies.
Electrodiagnostic results from 1,705 hands of patients with carpal tunnel syndrome (CTS) symptoms were reviewed retrospectively. All subjects were evaluated using routine nerve conduction studies: median sensory conduction recorded from digits 1 to 4, motor conduction from the abductor pollicis brevis muscle, and the 2L-INT DML comparison test.
Four hundred and one hands from a total of 1,705 were classified as having severe CTS. Among the severe CTS group, 56 hands (14.0%) showed absent median sensory and motor response in a routine nerve conduction study, and, of those hands, 42 (75.0%) showed an abnormal 2L-INT response.
The 2L-INT DML comparison test proved to be a valuable electrodiagnostic technique in localizing median mononeuropathy at the wrist, even in the most severe CTS patients.
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To verify the utility of the lateral femoral cutaneous nerve (LFCN) ultrasound-guided conduction technique compared to that of the conventional nerve conduction technique.
Fifty-eight legs of 29 healthy participants (18 males and 11 females; mean age, 42.7±14.9 years) were recruited. The conventional technique was performed bilaterally. The LFCN was localized by ultrasound. Cross-sectional area (CSA) of the LFCN and the distance between the anterior superior iliac spine (ASIS) and the LFCN was measured. The nerve conduction study was repeated with the corrected cathode location. Sensory nerve action potential (SNAP) amplitudes of the LFCN were recorded and compared between the ultrasound-guided and conventional techniques.
Mean body mass index of the participants was 23.7±3.5 kg/m2, CSA was 4.2±1.9 mm2, and the distance between the ASIS and LFCN was 5.6±1.7 mm. The mean amplitude values were 6.07±0.52 µV and 6.66±0.54 µV using the conventional and ultrasound-guided techniques, respectively. The SNAP amplitude of the LFCN using the ultrasound-guided technique was significantly larger than that recorded using the conventional technique.
Correcting the stimulation position using the ultrasound-guided technique helped obtain increased SNAP amplitude.
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To understand various morphologic types and locations of the sural nerve (SN) that are important for nerve conduction studies or nerve grafting procedures. The aim of this study was to describe the course and variations of the SN based on ultrasonographic findings for an adequate nerve conduction study.
A total of 112 SNs in 56 volunteers with no history of trauma or surgery were examined by ultrasonography. The location and formation of the SNs in relation to the medial and lateral sural cutaneous nerve were investigated. We measured the horizontal distance between the SNs and the midline of the calf at the level of 14 cm from the lateral malleolus, and the distance between the SNs and the most prominent part of the lateral malleolus.
SN variants was classified into four types according to the medial and lateral sural cutaneous nerve; type 1 (73.2%), type 2 (17.9%), type 3 (8.0%), and type 4 (0.9%). The mean distance between the SN and the midline of the calf was 1.02±0.63 cm, the SN and the most prominent part of the lateral malleolus was 2.14±0.15 cm.
Variations in the location and formation of the SN was examined by ultrasonography, and the results of this study would increase the accuracy of the SN conduction study.
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To evaluate each digital branch of the median sensory nerve and motor nerves to abductor pollicis brevis (APB) and 2nd lumbrical (2L) according to the severity of carpal tunnel syndrome (CTS).
A prospective study was performed in 67 hands of 41 patients with CTS consisting of mild, 23; moderate, 27; and severe cases, 17. Compound muscle action potentials (CMAPs) were obtained from APB and 2L, and median sensory nerve action potentials (SNAPs) were recorded from the thumb to the 4th digit. Parameters analyzed were latency of the median CMAP, latency difference of 2L and first palmar interosseous (PI), as well as latency and baseline to peak amplitude of the median SNAPs.
The onset and peak latencies of the median SNAPs revealed significant differences only in the 2nd digit, according to the severity of CTS, and abnormal rates of the latencies were significantly lower in the 2nd digit to a mild degree. The amplitude of SNAP and sensory nerve conduction velocities were more preserved in the 2nd digit in mild CTS and more affected in the 4th digit in severe CTS. CMAPs were not evoked with APB recording in 4 patients with severe CTS, but obtained in all patients with 2L recording. 2L-PI showed statistical significance according to the severity of CTS.
The branch to the 4th digit was mostly involved and the branch to the 2nd digit and 2L were less affected in the progress of CTS. The second digit recorded SNAPs and 2L recorded CMAPs would be valuable in the evaluation of severe CTS.
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To identify the optimal distal stimulation point for conventional deep peroneal motor nerve (DPN) conduction studies by a cadaveric dissection study.
DPN was examined in 30 ankles from 20 cadavers. The distance from the DPN to the tibialis anterior (TA) tendon was estimated at a point 8 cm proximal to the extensor digitorum brevis (EDB) muscle. Relationships between the DPN and tendons including TA, extensor hallucis longus (EHL), and extensor digitorum longus (EDL) tendons were established.
The median distance from the DPN to the TA tendon in all 30 cadaver ankles was 10 mm (range, 1-21 mm) at a point 8 cm proximal to the EDB muscle. The DPN was situated between EHL and EDL tendons in 18 cases (60%), between TA and EHL tendons in nine cases (30%), and lateral to the EDL tendon in three cases (10%).
The optimal distal stimulation point for the DPN conduction study was approximately 1 cm lateral to the TA tendon at the level of 8 cm proximal to the active electrode. The distal stimulation site for the DPN should be reconsidered in cases with a weaker distal response but without an accessory peroneal nerve.
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To derive normative values for ulnar nerve conduction study of the active recording electrode on the first dorsal interosseous muscle (FDI) and the reference electrode on the proximal phalanx of the thumb.
Ulnar nerve motor conduction study with FDI and abductor digiti minimi muscle (ADM) recording was performed in 214 hands of 107 healthy subjects. Ulnar NCS was performed with 2 different recording electrode montages (ADM-base of 5th finger; FDI-thumb) and differences in latency and amplitude were compared. Using this technique, the initial positivity of ulnar compound muscle action potential (CMAP) was not observed in any response with FDI recording.
The maximal values for distal motor latency to the ADM and FDI muscle were 3.8 ms and 4.4 ms, respectively. The maximal difference of distal motor latency between the bilateral FDI recordings was 0.6 ms. The maximal ipsilateral latency difference between ADM and FDI was 1.4 ms.
Placement of the reference electrode on the thumb results in a CMAP without an initial positivity and the normative values obtained may be useful in the diagnosis of ulnar neuropathy at the wrist.
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To understand the neural generator of double-peak potentials and the change of latency and amplitude of double peaks with aging.
In 50 healthy subjects made up of groups of 10 people per decade from the age of 20 to 60, orthodromic sensory nerve conduction studies were performed on the median nerves using submaximal stimulation. Various stimulus durations and interstimulation distances were used to obtain each double peak in the different age groups. The latency and amplitude of the second peak were measured. Statistical analyses included one-way ANOVA and correlation tests. p-values<0.05 were considered significant.
When the cathode moved in a proximal direction, the interpeak intervals increased. Second peak amplitudes decreased, and second peak latencies were delayed with aging (p<0.05). In some older people, second peaks were not obtained.
Our experiments indicate that the double-peak response represented the two stimulation sites under the cathode and anode. The delayed latency and decreased amplitude of the second peak that occurs with aging represented peripheral nerve degeneration in aging, which starts at the distal nerve.
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Objective: Electrophysiologic study and 24 hours urine study were analysed in patients with diabetes mellitus in order to assess the correlation between the severity of the diabetic neuropathy and degree of microalbuminuria.
Method: Two hundreds forty one patients with diabetic neuropathy were included and divided into 3 groups - mild, moderate and severe groups. The latency and amplitude of the peroneal motor nerve, median and sural sensory nerves, F-wave of the peroneal nerve and H-reflexes were measured. Microalbuminuria and creatinine clearance with 24 hours urine were studied. The results of the nerve conduction study and the degree of microalbuminuria were evaluated for the correlation between the two signs.
Results: The degree of microalbuminuria significantly increased in accordance with the electrophysiologic severity of neuropathy (p＜0.05). The latencies and amplitudes of the peroneal motor, median and sural sensory nerves had significant correlation with the degree of microalbuminuria (p＜0.05).
Conclusion: The degree of microalbuminuria was significantly correlated with the electrophysiologic severity of diabetic neuropathy. The results suggest that pathogenesis of the neuropathy and nephropathy in patients with diabetes seem the same as microvascular and biochemical basis. (J Korean Acad Rehab Med 2002; 26: 555-561)
Objective: To investigate the influence of electronic filter setting change on the parameters of motor and sensory nerve conduction studies.
Method: Median motor and sensory nerve conduction studies were performed in 25 neurologically healthy adult subjects with a mean age of 29 years (range, 20∼50). Compound muscle action potentials (CMAPs) and sensory nerve action potentials (SNAPs) were recorded after fixing the low frequency filter cutoff value of 1 Hz, 10 Hz, 100 Hz and 300 Hz and by changing high frequency filter cutoff level from 10 KHz to 0.5 KHz. Onset and peak latency, amplitude of CMAPs and SNAPs were measured and the area of CMAPs were also recorded. Dantec Counterpoint MK2 machine was used. Skin temperature was maintained at 34oC or above.
Results: As the high frequency filter was changed from 10 KHz to 0.5 KHz, the mean amplitude of SNAPs and CMAPs decreased by 33.5%, 3.3%, respectively. Onset and peak latency prolonged significantly below the high frequency filter level of 2 KHz (p＜0.01). When the low frequency filter was varied form 1 Hz to 300 Hz, large differences were seen in amplitude (69.7%) and area (86.5%) of CMAPs and amplitude of SNAPs (36.6%) (p＜0.01), but onset latency was not changed. Peak latency of CMAPs decreased by 20.8%, however, the peak latency of SNAPs reduced slightly (1.4%) (p＞0.01).
Conclusion: Significant alterations in parameters of CMAPs and SNAPs were produced by modification of filter setting. Optimum filter setting is recommended in nerve conduction study and filter parameters must remain constant when determining normal values and when performing serial studies on patients.
The diagnostic value of nerve conduction study of spinal stenosis is far limited due to its deeply located lesion and its very short length of diseased nerve compared to the relatively long length of total conduction distance. Recently it became possible to stimulate the deep sited spinal nerve roots non-invasively with magnetic stimulation. The authors made a new method to calculate the motor nerve conduction time of lumbar spinal root using magnetic stimulation and planned to verify the delayed conduction time in patients with spinal stenosis who didn't show any abnormalities in the conventional electrophysiologic studies(peripheral nerve conduction velocity, F-wave and needle EMG).
Three steps of magnetic stimulation were applied to vertex(transcortical stimulation), T12 spinous process(thoracic stimulation) and S1 spinous process(sacral stimulation), and three channel recording were performed at rectus abdominis(RA), right and left abductor hallucis(AH) simultaneously. Central motor conduction time(CMCT) was calculated by time difference between vertex and spinal stimulation at RA and AH. Lumbar-segment motor conduction time(LMCT) was defined as conduction time by subtracting CMCT of RA from CMCT of AH. The results as follows;
LMCT was delayed in the group of patients with spinal stenosis(5.36⁑2.11 msec) compared to the normal control group(4.05⁑1.23 msec), but the range of LMCT was not quite different individually. Dividing the patients group into multi-level and single-level spinal stenosis group, LMCT in the multi-level spinal stenosis group was 6.12⁑1.95 msec which was significantly different from that of single-level(4.48⁑1.96 msec). The authors conclude that LMCT, the short segmental motor nerve conduction study of lumbosacral nerve root, is useful to confirm the entrapment of spinal nerve root across the lumbosacral spinal canal and is also non- invasive, simple and applicable to any other spinal nerve roots.
Objective: To compare the degree of change of current perception threshold (CPT) results with the degree of nerve conduction study (NCS) change and evaluate the effectiveness of the CPT in following up patients who went through operation for carpal tunnel syndrome (CTS).
Method: Twenty hands with CTS were examined with CPT and NCS, before, 2 weeks after and 2 months after operation. In the CPT, the threshold of the median nerve was measured, in the NCS, amplitude and latency of the median nerve was measured. Subjects were divided into 3 groups according to the severity by NCS results and into 2 groups according to the subjective perception of improvement.
Results: The subjects mean age was 51.4. Changes of NCS results in amplitude and latency showed no statistical relevance. CPT study result changes demonstrated to be statistically significant. Improvement of CPT results seen in the period of 2 weeks and 2 months and the initial first 2 weeks showed no difference. Change of CPT results showed correlation not in accordance with the severity of the NCS study, but with the symptomatic improvement of the patients.
Conclusion: CPT can be an effective tool in evaluating the improvement of symptoms and may be used as a follow up tool in patients with CTS. (J Korean Acad Rehab Med 2002; 26: 414-419)
Objective: High body temperature may alter nerve conduction in demyelinated neurons. This study was designed to investigate the changes in nerve conduction parameters in response to the heat applied over the wrist in the patients with carpal tunnel syndrome (CTS).
Method: 16 hands of CTS patients and 16 hands of normal subjects were involved in this study. Motor and sensory nerve responses were measured at 32oC and 42oC in all the subjects. Infrared was applied on the wrist to warm the skin to 42oC. Changes of relative amplitude, duration, and latency of evoked potentials in median sensory and motor nerves of CTS patients were compared with those of the normal subjects. Correlation between the latency measured at 32oC and changes of amplitude of motor and sensory nerve responses after warming to 42oC was evaluated in CTS group.
Results: Relative reduction in duration of motor responses in CTS group was significantly greater than in normal group. Relative reduction of motor and sensory amplitude, and sensory latency were greater in CTS. There was no significant relation between motor and sensory latency at 32oC and relative amplitude reduction in motor and sensory responses at 42oC.
Conclusion: Increase in temperature may increase the number of blocked nerve fibers in patients with CTS than in normal subjects.
Objective: To determine whether there is a difference in nerve conduction studies depend on the body mass index (BMI) of subjects
Method: Twenty normal healthy volunteers were enrolled for the study. A routine usual sensory and motor nerve conduction study and a sensory nerve conduction study using the near nerve needle technique were performed. BMI was calculated as weight (kg) divided by height (m) squared. In order to evaluate the effect of BMI on the various measurements of the nerve conduction study, one-way analysis of variance (ANOVA) was used.
Results: The sensory nerve amplitudes of median, ulnar and sural nerves correlated significantly (p＜0.05) with BMI. However, no correlation was noted between BMI and sensory nerve amplitude by near nerve needle technique. There was no statistical differences noted in the measurements of latency of examined motor and sensory nerves neither the velocity of examined motor nerves.
Conclusion: In clinical practice, the effect of BMI should be taken into account when the interpretation of abnormal sensory nerve study has to be soli. (J Korean Acad Rehab Med 2002; 26: 316-320)
Method: Subjects were 22 patients with AVF in patients with CRF and 10 controls without AVF in patients with CRF. We studied nerve conductions, and compared the findings in the arms with fistula and without fistula, and the arms in controls.
Results: In ulnar motor nerve conduction study, the amplitude in fistula side was lower than non-fistula side, but the conduction velocity in non-fistula side was lower than fistula side. In radial motor nerve conduction study, the distal latency in non-fistula side was more delayed than that in fistula side. There were no statistical significancies between fistula side and non-fistula side in the other nerve conduction study parameters in arms. And there was no statistically different incidences of carpal tunnel syndrome in both sides. Comparing with controls, conduction velocities of ulnar and radial motor nerves and peak latencies of ulnar and radial sensory nerves were more delayed in both sides.
Conclusion: There were no significant local effects of arteriovenous fistula on nerve conductions in patients with chronic renal failure. (J Korean Acad Rehab Med 2003; 27: 912-916)
Objective: To compare current perception threshold with nerve conduction study, we measured current perception threshold (CPT) in healthy control and patients with carpal tunnel syndrome (CTS).
Method: Twenty control subjects and twenty patients with CTS were included. Latency and amplitude of median and ulnar motor and sensory nerves were measured. The sensory current perception threshold was measured at the distal interphalangeal joint of third and fifth fingers and the palm with electrical current of 5 Hz, 250 Hz, and 2,000 Hz in frequency. We compared the results of the nerve conduction study with the data of the CPT.
Results: We found that measuring of the sensory threshold might detect carpal tunnel syndrome, especially with 2,000 Hz and 250 Hz stimulation and that CPT data correlated to sensory latency and amplitude of the median nerve.
Conclusion: The sensory threshold test might be useful for diagnosis and follow up test in carpal tunnel syndrome.
Objective: To determine the reference values for the diagnosis of isolated entrapment neuropathies of medial and lateral plantar nerve and inferior calcaneal nerve distal to the tarsal tunnel.
Method: The subjects were neurologically healthy 30 adults (15 males, 15 females). Distal motor nerve conduction study of medial and lateral plantar nerves and inferior calcaneal nerve was performed. The recording muscles for medial and lateral plantar nerves and inferior calcaneal nerve were flexor hallucis brevis, flexor digiti minimi brevis, and abductor digiti minimi pedis, respectively. The stimulation was done at distal and proximal to the tarsal tunnel to differentiate the tarsal tunnel syndrome and the entrapment neuropathy of distal to the tarsal tunnel. The distance of recording and distal stimulation site was fixed to 10 cm for medial and lateral plantar nerves. The skin temperature was maintained 33oC or above. The proximal latency, distal latency, peak to peak amplitude, conduction velocity and residual latency were measured. The reference values were obtained by 95 percentile values.
Results: The reference values for the diagnosis of isolated entrapment neuropathies of medial plantar nerve, lateral plantar nerve and inferior calcaneal nerve distal to tarsal tunnel are as follows.
1) Medial plantar nerve: distal latency, ＞ 4.3 msec; side to side difference, ＞ 0.7 msec
2) Lateral plantar nerve: distal latency, ＞ 4.1 msec; side to side difference, ＞ 0.6 msec
3) Latency difference of medial and lateral plantar nerve: ＞ 0.7 msec
4) Inferior calcaneal nerve: distal latency, ＞ 4.3 msec; distal peak latency, ＞ 7.2 msec; side to side difference of distal onset latency, ＞ 1.5 msec; side to side difference of distal peak latency, ＞ 0.8 msec; residual latency, ＞ 3.0 msec
Conclusion: The distal motor nerve conduction method used in this study and the reference values could be used to differentiate entrapment neuropathies of medial and lateral plantar nerve and inferior calcaneal nerve distal to the tarsal tunnel from tarsal tunnel syndrome.
Method: Ulnar motor nerve conduction studies were performed bilaterally in twenty healthy adult volunteers. For each limb, nerve conduction study was carried out in two different positions. In the first position, shoulder were abducted, elbow and wrist flexed to 90o. For the second position, all joints were kept constant except for the wrist where it was extended. Routine conduction study was performed in both wrist positions. All data were statistically analyzed.
Results: The average conduction velocities in the wrist flexed position were 61.6 m/sec for the forearm segment and 62.3 m/sec across elbow. With the wrist extended, the average was 62.6 m/sec and 64.1 m/sec, respectively. The differences in conduction velocities between two different wrist positions were statistically significant (p＜0.05). In the wrist flexed position, the average measured latencies were 2.3 msec with wrist, 5.4 msec below elbow, and 7.4 msec above elbow stimulation, compared to wrist extended which showed 2.4, 5.4 and 7.2 msec, respectively. The difference of latencies at wrist between the two wrist positions was statistically significant (p＜0.05).
Conclusion: The authors conclude that wrist position affect ulnar nerve conduction velocity.
Objective: The dorsomedial cutaneous nerve (DMCN) to the great toe is a branch of the medial dorsal cutaneous nerve, which originates from the superficial peroneal nerve. The objective of this study is to standardize the electrodiagnostic technique, and to investigate the usefulness of dorsomedial cutaneous nerve (DMCN) conduction study in patients with peripheral neuropathy.
Method: Sixty two legs in 31 normal adults and 56 legs in 28 patients with the clinical signs and symptoms as well as electrodiagnostic evidences of peripheral neuropathy were evaluated with the DMCN conduction study. The stimulating electrode was placed over the lateral 1/3 between medial and lateral malleoli and the active electrode was placed over 12 mm medial and 10 mm proximal to the extensor hallucis longus tendon over the 1st metatarsophalangeal joint.
Results: The mean values of DMCN conduction study in normal adults were 2.95⁑0.47 msec for onset latency, 3.58⁑0.43 msec for peak latency, 6.67⁑2.87μV in amplitude, and 12.96⁑1.17 cm for distance from active electrode to stimulation point. There were statistically significant differences between normal and patients groups in all parameters except the distance.
Conclusion: A method for DMCN conduction study was introduced which could be used as a valuable technique for the early evaluation of peripheral 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.
Leprosy is an infectious disease caused by Mycobacterium leprae and characterized by dermal and peripheral nerve lesions. The facial nerve is also frequently involved in leprosy. There are a few electrophysiologic studies on the facial nerve involvement in leprosy patients, but there is no electrophysiologic study on the facial nerve involvement in cured leprosy patitents. So we performed facial nerve conduction study and Blink reflex study in 19 cured leprosy patients who have been managed with Dapsone for a long time. Facial motor latencies were prolonged in 11 patients(57.9%).: 10 of 15 patients in lepromatous type; 1 of 4 patients in tuberculoid type. Prolonged latencies were shown in temporal branch, zygomatic branch, buccal branch, and mandibular branch in 9(47.4%), 6(31.6%), 5(26.3%), and 3(15.8%), respectively. Blink reflex study suggests combined facial nerve and trigeminal nerve lesion in 2 patients.
Objective: To evaluate the clinical findings and the results of an electrophysiological study in seven patients with a systemic necrotizing vasculitis and neuropathy.
Method: Clinical and electrophysiological studies were performed in seven patients of whom three had a polyarteritis nodosa, other three a Churg-Strauss syndrome, and one an overlapping syndrome.
Results: In the electrophysiological study, five patients presented an overlapping multiple mononeuropathy, one a multiple mononeuropathy and the other one a distal symmetric polyneuropathy. The neuropathies were mainly axonopathies with a decreased amplitude of compound motor action potential and sensory nerve action potential; however one patient showed the conduction blocks in the tested nerves. In electromyography, the most prominent feature was a neurogenic pattern with fibrillation potentials and reduced recruitments. No patient had a myopathic pattern.
Conclusion: The most prominent features of the systemic necrotizing vasculitis patients with neuropathy were the axonopathic findings in the nerve conduction studies and neurogenic pattern in the electromyographic studies. Electrodiagnostic study was helpful for the diagnosis of vasculitic neuropathy, however further studies would be necessary to clarify the characteristics of the neuropathy of polyarteritis nodosa and the Churg-Strauss syndrome.
Objective: To investigate the character of peripheral neuropathy associated with end-stage liver disease and the effect of liver transplantation on peripheral neuropathy.
Method: Twenty five patients admitted for a liver transplantation were involved in this study. All patients underwent nerve conduction study before liver transplantation and 6 months after liver transplantation. Based on results of this study, motor amplitude (MAS), motor velocity (MVS), sensory amplitude (SAS), and sensory velocity score (SVS) were calculated. Neuropathy symptom score (NSS), and neuropathy disability score (NDS) were estimated. The scores from the nerve conduction study were compared with NSS and NDS to find out the correlation between them. The changes in nerve conduction study, NSS and NDS after liver transplantation were evaluated.
Results: All patients had abnormalities on their nerve conduction study preoperatively, but 10 patients (40%) showed normal findings 6 months after transplantation. Only SAS disclosed significant correlation with NDS preoperatively. SAS, SVS, and MVS showed significant correlation with NDS after transplantation. SAS and MVS substantially increased after transplantation.
Conclusion: Nerve conduction study showed the improvement both in sensory and motor nerve after liver transplantation. The correlation between the nerve conduction study and clinical estimates after liver transplantation was closer than before the transplantation.
Objective: To evaluate the characteristics of peripheral nervous system involvement in patients with mucopolysaccharidoses (MPS).
Method: Electrophysiologic studies were performed in 26 children with MPS confirmed by semiquantitative MPS study, high resolution electrophoresis and enzyme assay. The age distribution of the patients were 2 to 18 year old (mean 8.2 year old).
Results: Of the 26 children, 21 children (80.8%) showed abnormal electrophysiologic finding. Eighteen children had median entrapment neuropathy at wrist level (carpal tunnel syndrome), 3 children had demyelinating peripheral polyneuropathies dominant in motor nerves.
Conclusion: The most prominent features of the peripheral nervous system involvement in MPS patients were entrapment neuropathy at wrist but concomittent peripheral polyneuropathy. Further studies would be necessary to clarify the characteristics of the peripheral polyneuropathy in MPS.
Sixteen legs in eight cadavera were dissected to observe the anatomic course of the superficial peroneal nerve around the ankle and the superficial peroneal sensory conduction study was performed in twenty-eight normal subjects. The anatomic course of the superficial peroneal nerve around the ankle was in two types, type I and type II. Type I was 13 cases(81%) and type II was 3 cases(19%). In type I, the nerve penetrated the crural fascia and became subcutaneous at 8.8⁑1.1 cm proximal to the ankle joint and divided into two major branches at 2.6⁑1.1 cm proximal to the ankle. Medial and intermediate dorsal cutaneous nerves were located at 47%(⁑3.4%) and 35%(⁑4.9%) of the intermalleolar distance from lateral malleolus, respectively. In type II, the medial and intermediate dorsal cutaneous nerve arose seperately from the superficial peroneal nerve at 8.0⁑0.9 cm proximal to the ankle joint. Medial and intermediate dorsal cutaneous nerves were located at 49%(⁑5.6%) and 33%(⁑4.0%) of the intermalleolar distance from the lateral malleolus, respectively. Superficial peroneal sensory conduction study was performed based on the findings of type I. The mean distal latencies and amplitudes were 3.21⁑0.35 msec, 12.1⁑3.37 ㄍV and 3.17⁑0.37msec, 14.54⁑4.60 ㄍV in medial and intermediate dorsal cutaneous nerves, respectively.
Objective: To investigate the possibility of volume conduction in the superficial radial sensory nerve conduction study in patients with a complete radial nerve injury.
Method: In patients with a complete radial neuropathy, a superficial radial sensory nerve conduction study was carried out by an antidromic and orthodromic methods. Antidromic technique was carried out by increasing stimulus intensity gradually. Median palmar cutaneous nerve conduction study was also carried out by an antidromic method.
Results: When the stimulus intensity was significantly higher than the optimal technique, a median palmar cutaneous nerve action potential was evoked instead of the superficial radial nerve action potential. This is a volume conducting potential which occurrs following a high intensity stimulus.
Conclusion: Superficial radial sensory conduction study must be carried out by an optimal stimulus intensity and an orthodromic method to eliminate the effect of volume conduction.
Objective: The aim of present study is to obtain the reference values of motor and sensory nerve conduction study (NCS) of the median nerve and to re-assess the values of criteria for abnormal findings in the electrophysiological diagnosis of Carpal tunnel syndrome (CTS).
Method: Median and ulnar NCS were performed in 62 neurologically healthy adults as controls and 142 patients with CTS. Reference values of the median and ulnar NCS were obtained from the controls and the criteria for the diagnosis of CTS were made. Sensitivities of diagnostic criteria were calculated.
Results: The criteria included 7 items: (1) A 5-cm short segment study through carpal tunnel, ≥1.3 msec; (2) median motor latency (8 cm), ≥4.0 msec; (3) median sensory latency (14 cm, onset), ≥3.0 msec; (4) median sensory nerve action potential amplitude (baseline to peak), ≤20 uV; (5) ratio of median to ulnar motor latency, ≥1.5; (6) ratio of median to ulnar sensory latency, ≥1.2; (7) ratio of median to ulnar sensory amplitude, ≤0.6. The order of the highest to lowest sensitivity were as follows: a 5-cm short segment study, median sensory latency, median motor latency, ratio of median to ulnar sensory latency, and ratio of median to ulnar motor latency. Approximately 65% of the patients met all the 7 diagnostic criteria and 95% of the patients met 3 or more.
Conclusion: The criteria proposed in this study would enhance the diagnostic sensitivity for the CTS.
Objective: To explore the diagnostic value of the nerve conduction study in the dorsal nerve of penis before and after erection.
Method: Nineteen subjects with a confirmed psychogenic impotence were studied for the superficial peroneal and sural sensory nerve conductions, bulbocavernous reflexes (BCR), tibial and pudendal somatosensory evoked potentials (SEP), and conduction studies of the dorsal nerve of penis. Sixteen subjects with normal findings had repeat studies after an injection of Prostaglandin E1.
Results: Erection helped to obtain a dorsal penile sensory potentials in 18.8% of the 16 subjects. The mean conduction velocity of the dorsal nerve of penis increased significantly from 33.8⁑9.3 m/sec to 48.4⁑12.8 m/sec. The mean sensory amplitude of the dorsal nerve of penis increased significantly from 1.7⁑1.0 ㄍV to 2.8⁑1.4 ㄍV. There was no significant difference in the BCR latency and the pudendal SEP (latency and amplitude) before and after erection.
Conclusion: Erection helps to obtain the sensory potentials of the dorsal nerve of penis when it is technically difficult to obtain and increases the conduction velocity as well as amplitude of the dorsal nerve of penis. However it does not affect the BCR latency and pudendal SEP.
Method: The subjects were 50 healthy adults (mean age, 45.6 years) without the clinical signs and symptoms of peripheral neuropathy. All subjects underwent electrodiagnostic evaluation of the following sensory nerves in lower limbs: superficial peroneal, sural, proximal sural, lateral dorsal cutaneous branch of sural nerve (LDSN), and medial plantar. Examined late responses included: tibial F-wave, peroneal F-wave, and H-reflex recorded from the soleus muscle.
Results: No response rates of sensory nerve conduction studies such as superficial peroneal, sural, proximal sural, LDSN, and medial plantar nerves were 2%, 0%, 0%, 24%, and 18%, respectively. No response rates of late responses such as tibial F-wave, peroneal F-wave, and H-reflex were 0%, 2%, and 8%, respectively. And no response rates were significantly correlated with age (p＜0.05).
Conclusion: No response rate of sensory and late responses of lower limbs are relevant to age increments, the results should be considered for an early diagnosis of peripheral neuropathy in the lower limbs of old population. (J Korean Acad Rehab Med 2003; 27: 220-223)
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 find out the incidence of reduced median conduction velocity of forearm (MNCV-F) in carpal tunnel syndrome (CTS) and to compare clinical and electrophysiologic characteristics of CTS with reduced MNCV-F and to observe the changes of reduced MNCV-F after carpal tunnel release.
Method: One hundred and fifty nine hands with CTS are divided into two groups; MNCV-F of 50 m/sec and above as group I and that of below 50 m/sec as group II. For the electrophysiologic comparison, median sensorimotor distal latency, peak-to-peak amplitudes and abnormal spontaneous activity of abductor pollicis brevis were observed and for clinical comparison, sensorimotor symptoms, Phalen and Tinel sign were observed. Twenty four hands which had successful carpal tunnel release were examined for the changes of MNCV-F.
Results: The hands with reduced MNCV-F were 29 among 159 hands. Sensorimotor distal latency were significantly prolonged and sensorimotor amplitudes also significantly reduced in group II. Sensory change and Phalen signs were more frequently observed in group II. MNCV-F in group I had not changed after carpal tunnel release, but MNCV-F in group II was improved significantly. The changes MNCV-F in group II were much delayed than the improvement of parameters of distal conduction studies.
Conclusion: The incidence of reduced MNCV-F in CTS was 18.24%. Patients with reduced MNCV-F had more severe CTS both electrophysiologically and clinically. Reduced MNCV-F had improved significantly, but there was significant time gap between the electrophysiologic improvements of distal and proximal portions of nerve. This findings may suggest that retrograde degeneration may play a partial role in reduced forearm motor nerve conduction velocity of the median nerve in CTS.
Objective: To evaluate the clinical usefulness of current perception threshold (CPT) test in diagnosing the diabetic neuropathy.
Method: We have recorded the neuropathic symptom score (NSS), CPT and the parameters of nerve conduction study (NCS) in 45 patients with diabetes. NSS was calculated according to the clinical symptom and signs, and the score more than 3 was regarded as abnormal (neuropathic). CPT was measured at the 2nd finger and 1st toe delivering the three different frequencies (2000, 250 and 5 Hz) of current and conventional NCS were performed at the median, peroneal motor and sural nerves. All the patients were assigned to three groups according to the result of NSS and NCS; group A, abnormal NSS and NCS; group B, abnormal NSS only; group C, normal NSS and NCS. CPT was compared between groups, and we investigated the correlation between CPT and NSS, and parameters of NCS. Also the sensitivity and specificity of CPT test were calculated.
Results: The mean CPT was significantly increased in the entire diabetic groups as compared with control group (p＜0.05). CPTs measured by 2000 Hz stimulation at the finger and toe were positively correlated with the most parameters of NCS (p＜0.05), and CPT was more highly correlated with NCS (p＜0.05) than NSS. The sensitivity and specificity of the CPT were 94.1% and 10.7%, respectively.
Conclusion: The CPT test may have added value in diagnosing the diabetic neuropathy as a screening.
Slowing in forearm median nerve conduction in patients with carpal tunnel syndrome(CTS) has been described. But the cause of slowing is still unclear whether it is related to a technical artifact on electrodiagnostic approach or pathophysiologic changes in the proximal segment of median nerve. To investigate the possible retrograde degeneration of median nerve in the forearm segment(wrist to elbow) in patients with known carpal tunnel syndrome, the median nerve conduction studies were performed in 23 normal persons as control and 25 patients with carpal tunnel syndrome. To evaluate the median nerve conductions in the forearm, the recording bar-electrode were placed at the volar aspect of the wrist and stimulating electrodes were applied at the elbow area. The mixed nerve action potentials and conduction velocities were measured.
The median mixed nerve action potential(FNAP) amplitudes recorded at the wrist and motor nerve conduction velocity(MMCV) in patients with carpal tunnel syndrome patients were significantly reduced compared to those of control group(p<0.05). However, the median mixed nerve conduction velocity(FNCV) was not reduced significantly. The median mixed nerve action potential amplitudes demonstrated positive correlation with the decrease of motor and sensory action potential amplitudes and velocities.
This result suggests that the retrograde degeneration progresses as the carpal tunnel syndrome progresses and the retrograde degeneration may play a major role in reduced motor nerve conduction velocity of the median nerve in the forearm. We propose that FNAP amplitude and MMCV might be used to evaluate the severity of retrograde degeneration in patients with carpal tunnel syndrome.
Objective: To determine the effect of exercise in the early phase of reinnervation after sciatic nerve injuries in the rat.
Method: Thirty six rats, Sprague-Dawley (weight, 200 to 220 g), were divided into the normal control and experimental groups. Using a haemostatic forceps, crushing injuries to the bilateral sciatic nerves were induced in the experimental group. The experimental group was further divided into exercise groups by the duration of daily swimming and initiation (duration since injury) of exercise after nerve injury (A, 2 hours/day and day 1; B, 30 minutes/day and day 1; C, 2 hours/day and week 2; D, 30 minutes/day and week 2) and non-exercise group (E). After completion of 5-week program the test results were evaluated by 1) sciatic nerve motor conduction study recorded at the gastro-soleus muscles, 2) measurement of soleus muscle tension, and 3) hematoxylin-eosin stain & alkaline ATPase stain (pH 9.4) of the soleus muscles.
Results: Nerve conduction study revealed significantly prolonged latency in group C and decreased amplitude in the group C, D. Peak twich tension decreased significantly in group C, D & E. Maximal tetanic tension was increased significantly in the group A compared to C. Both type I and II muscle fibers atrophied significantly in all the experimental groups compared to the normal control group with no changes of the composition of two muscle fibers.
Conclusion: Swimming applied from the early phase after sciatic nerve injury may be beneficial in early recovery of muscle tension. Overexercise in the early stage of reinnervation, however, may hamper the functional return of the damaged muscle by nerve injury.
Objectives: The current literature gives confusing advice on the position of the elbow in ulnar nerve conduction study. The purpose of this study was to determine the appropriate position of elbow flexion for a segmental ulnar nerve conduction study and to attain the basic information for an evaluation of ulnar neuropathy.
Methods: Segmental ulnar motor and sensory nerve conduction studies were performed bilaterally on 40 healthy korean adults(20 men and 20 women) with the age range from 19 to 56 years(mean age：29.86). The ulnar nerve was stimulated at 7 cm & 10 cm proximal to the active recording electrode respectively and 5 cm distal, and poximal to the medial epicondyle of the humerus for motor and sensory nerves at each elbow flexion position of 0o, 45o, 90o, and 135o. The segmental distances were measured in each position.
Results: The segmental nerve conduction velocity(NCV) of the elbow segment increased with the degree of elbow flexion, and it was faster than the forearm segment at 90o and 135o of elbow flexion. The NCV showed no statistical difference in each elbow position.
Conclusion: We conclude that the degree of elbow flexion should be maintained 90o or above in an ulnar nerve conduction study.
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