• Biomedical Science Letters
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• v.11 no.2
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• pp.193-199
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• 2005

The present study was performed to assess peripheral neural involvement by exposure to hand-arm vibration. Segmental sensory nerve conduction in the median and ulnar nerves were measured in shipyard workers exposed to vibration. The subjects were 47 male adults exposed to hand-arm vibration and 7 healthy male controls. The subjects underwent an extensive bilateral neurophysiological examination. Sensory compound nerve action potential (SNAP) of the median and ulnar nerves in palm-finger and wrist-palm segments were measured by antidromic method. And SNAP of the median and ulnar nerves in wrist-proximal finger and wrist-distal finger segments were measured by orthodromic method. Result of sensory nerve conduction study was abnormal in 31 patients $(66\%)$ and normal in 16 patients $(34\%)$ of subjects. The pathological pattern in the hand-arm vibration exposed group was 13 patients $(28\%)$ of carpal tunnel syndrome, 18 patients $(38\%)$ of distal sensory neuropathy, 7 patients $(15\%)$ of multifocal and 1 patient $(2\%)$ of Guyon syndrome. The present study indicates that vibration-induced nerve impairments exist both in the finger-palm and palm-wrist segment of median and ulnar sensory nerves. The results suggest that segmental sensory nerve conduction study would be useful as objective indication of peripheral nerve impairment induced by the hand-arm vibration.

• Journal of Medicine and Life Science
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• v.15 no.2
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• pp.101-104
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• 2018

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy caused by focal compression of the median nerve in the carpal tunnel. However, many patients with CTS, who are diagnosed clinically and confirmed with electrophysiological studies, complain of the sensory symptoms extends to the ulnar nerve territory. The aim of this study was to evaluate whether a dysfunction in sensory fibers of the ulnar nerve was present or not in hands with CTS patients who had extramedian spread of sensory symptoms over the hand. We retrospectively analyzed the recording of the subjects who were diagnosed with CTS within a one-year-period of time. After exclusions, 136 hands recordings of 87 patient were included. We compared the results of median and ulnar nerve sensory conduction studies between normal hands and hands with CTS. We did not detect statistically significant difference on all parameters of ulnar nerve sensory conduction studies between the normal hands and the hands with CTS. The parameters of the obtained in median nerve sensory conduction studies were statistically different between the healthy control and CTS patients. The hands with CTS showed similar rate of ulnar sensory conduction abnormalities compared with the normal hands. In conclusion, our study showed that none of the parameters in ulnar sensory nerve conduction studies differ between two groups. Accordingly, our study revealed that ulnar nerve involvement does not contribute in CTS patients underlying the spread of paresthesia extends to the ulnar nerve territory.

• Annals of Clinical Neurophysiology
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• v.7 no.2
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• pp.97-100
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• 2005

Background: The most distal sensory fibers of the feet are often affected first in polyneuropathy. However, they are not evaluated in routine nerve conduction studies. Thus we evaluated the dorsal sural sensory nerve in patients with sensorimotor polyneuropathy with normal sural response, in order to assess the usefulness in electrodiagnostic practice. Methods: In this study, 53 healthy subjects and 27 patients with clinical evidence of sensorimotor polyneuropathy were included. In all subjects, peripheral motor and sensory nerve studies were performed on the upper and lower limbs including dorsal sural nerve conduction studies. On electrodiagnostic testing, all patients had normal sural responses. Results: The dorsal sural sensory nerve action potentials (SNAPs) mean amplitude was $13.12{\pm}5.68{\mu}V$, mean latency was $3.12{\pm}0.43msec$, and mean sensory conduction velocity (SCV) was $36.50{\pm}3.40m/s$ in healthy subjects. In 7 of 27 patients, the dorsal sural nerve SNAPs were absent bilaterally, and in 20 patients, the mean dorsal sural nerve distal latency was longer($3.40{\pm}0.48ms$, P=0.006), and mean SCV was slower than in healthy subjects($35.08{\pm}4.59$, P=0.043). However, dorsal sural nerve amplitude was not different between the groups (P=0.072). Conclusions: Our findings suggest that dorsal sural nerve conduction studies should be included in the routine electrodiagnostic evaluation of patients with suspected polyneuropathy and normal sural nerve responses.

• Annals of Clinical Neurophysiology
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• v.12 no.1
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• pp.16-20
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• 2010

Background: The medial plantar nerve (MPN) is a distal branch of the posterior tibial nerve, and various methods of nerve conduction study for MPN have been introduced so far. Hemmi et al described a new method (Hemmi's method) for recording medial plantar sensory nerve action potentials (SNAPs), which is considered as a simple and reliable method for measuring medial plantar SNAPs. This study was aimed to establish the normal values for the MPN conduction study among Koreans and to compare the sensitivities of three different methods for MPN conduction study (Hemmi, Oh, and Saeed's method) in detecting evidence of peripheral neuropathy among diabetic patients. Methods: In 27 healthy subjects, MPN conduction study using Hemmi's method was performed and normal values were calculated. In 54 diabetic patients who showed normal routine nerve conduction studies, three different methods for MPN conduction study were performed and diagnostic sensitivity of each method were compared. Results: In normal subjects, the mean medial plantar SNAP amplitude and conduction velocities measured by Hemmi's method were $4.3{\pm}1.0$ uV and $38.3{\pm}6.8$ m/s respectively. Among 54 patients with diabetes who showed normal routine nerve conduction studies, medial plantar SNAP was not obtainable in 28, 31, and 6 patients by Hemmi, Oh and Saeed's method respectively. Conclusions: In terms of the diagnostic sensitivity for detecting diabetic neuropathy, there had been no significant statistical difference between three different methods. Our study suggested that MPN conduction study using Hemmi's method is simple and useful screening test for early diabetic neuropathy, and is comparable with Oh's method.

• Annals of Clinical Neurophysiology
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• v.8 no.2
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• pp.152-157
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• 2006

Background: Meralgia paresthesia (MP) is characterized by sensory impairment in the anterolateral aspect of the thigh and usually caused by a lateral femoral cutaneous nerve (LFCN) lesion. It is well known that several physiologic factors including age, obesity, and sex can affect nerve conduction. This study aimed to determine whether body mass index (BMI) and age can influence on the conduction velocity and action potential amplitude of the LFCN. Methods: Fifty six individuals without any previous neuromuscular disease participated in this study. LFCN was studied orthodromically, distally from the anterior superior iliac spine. The values, such as sensory nerve action potential (SNAP) amplitude and sensory nerve conduction velocity (NCV) were obtained. SNAP of the LFCN were formed on both sides in forty three individuals. Results: No difference of demographic factors was observed between two groups divided according to the presence of SNAP formation. BMI had a significant relationship with SNAP amplitude and NCV of the LFCN. Moreover, Multiple regression analyses of nerve conduction values showed the significant correlation of body mass index and age with nerve conduction velocity. Conclusions: We may suggest that nerve conduction of the LFCN can be affected by age and BMI. Further study to obtain normal nerve conduction data and compare these data with those of meralgia paresthetica patients should be continued.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.3
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• pp.212-215
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• 2005

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy in clinical practice, with a 0.1% life time risk in the general population. Conventional neurophysiological studies have been useful in the diagnosis of this condition, as have a number of more specialized procedures. Therefore, we evaluated the diagnostic sensitivities of several parameters in nerve conduction technique for CTS patients. We analyzed 100 patients (159 hands) who were diagnosed with CTS clinically and electrophysiolosically. Median motor and sensory nerve conduction velocities (MCV and SCV) with wrist, palm, and finger stimulation were performed in traditional methods. Sensitivities of each test were calculated and compared to normal control data. The sensitivities of existing nerve conduction method were noted in terminal latency on median nerve, 2nd finger-wrist segment, 3rd finger-wrist segment, palm-wrist segment and distoproximal ratio, as 72.96%, 92.45%, 94.34%, 94.97%, and 97.48%, respectively. In the early course of CTS, sensory nerve conductions in the median nerve are more valuable than motor nerve conduction. Sensory nerve conductions are usually affected before motor nerve conductions in CTS. In this study, we detected that slowing of median SCV was the most frequent in the distoproximal ratio.

• Annals of Clinical Neurophysiology
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• v.6 no.1
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• pp.14-19
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• 2004

Backgrounds and objectives: POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome is the rare cause of polyneuropathy. Although the polyneuropathy is essential for the diagnosis of the disease, the pattern of electrodiagnostic abnormalities has not been characterized in detail. The purpose of this study was to elucidate the features of nerve conduction abnormalities in POEMS syndrome. Methods: We reviewed the medical records and nerve conduction studies (NCS) of 12 consecutive patients with POEMS. Results: A total of 68 motor and 46 sensory nerves were examined. Compound muscle action potentials (CMAPs) and sensory nerve action potentials were abnormally attenuated or not elicited in majority of motor and sensory nerves (80.88% in motor, and 82.6% in sensory nerves). Frequency of the nerves with no potential was significantly higher in lower limbs than in upper limbs (p<0.01 in both motor and sensory nerves), and CMAP amplitude was more reduced in lower limbs than in upper limbs (p<0.01). Conduction slowing was very frequently observed with 95% and 76% of motor and sensory nerves, respectively, having the abnormally reduced values of conduction velocity. Distal motor latencies were abnormally prolonged in 75% of motor nerves, and terminal latency indices were significantly higher in patients than in normal controls (p < 0.05). Conduction block was observed only in 5% of motor nerves. Conclusions: NCS in POEMS syndrome showed characteristic patterns, in which conduction abnormalities were more frequently and severely affected in the lower limbs, and more predominantly in the intermediate nerve segments than in the distal portions. The recognition of these characteristic patterns may be helpful in early diagnosis of polyneuropathy in POEMS syndrome.

• Annals of Clinical Neurophysiology
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• v.3 no.1
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• pp.15-20
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• 2001

Background : Carpal tunnel syndrome(CTS) is the most common entrapment neuropathy that refers to a group of signs and symptoms resulting from compression of the median nerve at the wrist. The course of CTS in older patients is different from the younger patients. This difference may be the result of different underlying mechanisms. The different nerve conduction studies of CTS may signify different approaches in management. This study was done to assess the differences in nerve conduction study of CTS in younger and older patients. Methods : This study involved 224 patients who visited Gachon Medical School, Gil Medical Center and was diagnosed by nerve conduction study from October 1997 to October 1999. We compared the results of nerve conduction study to age, especially in between those under 60 years and those 60 years or over CTS patients. Nerve conduction study consists of motor studies of both median nerves(terminal latency, compound action potential) and sensory studies(nerve conduction velocity, nerve action potential). And we also evaluated the variables between younger and older patients group. Those variables include sex, symptom period, laterality, abnormal physical findings and radiculopathy. Results : We found that a significant increase of terminal latency(p<0.1), but a decrease in compound motor action potential(p<0.05) in older patient's group. There was no significant differences in sensory nerve conduction velocity and action potential between those under 60 years and those 60 years or even patients. And also there was no significant difference in sex, symptom period, laterality, abnormal physical findings, radiculopathy between older and younger patients. Conclusions : This study showed a significant increase in the terminal latency and a decrease in compound action potential in older patients. The different nerve conduction studies of CTS by age effect may need different approaches in management.

• Annals of Clinical Neurophysiology
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• v.8 no.2
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• pp.146-151
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• 2006

Background: Tarsal tunnel syndrome (TTS) is an entrapment neuropathy of the tibial nerve within fibrous tunnel on the medial side of the ankle. The most common cause of TTS is idiopathic. This is a retrospective study to define the electrophysiological characteristics of idiopathic TTS. Methods: We reviewed the medical and electrophysiological records of consecutive patients with foot sensory symptoms referred to electromyography laboratory. Inclusion of patients was based on clinical findings suggestive of TTS. Among them, patients with any other possible causes of sensory symptoms on the foot were excluded. Control data were obtained from 19 age-matched people with no sensory symptoms or signs. Routine motor and sensory nerve conduction study (NCS) including medial plantar nerve (MPN) using surface electrodes were performed. Result: Twenty one patients (13 women, 8 men, 9 unilateral, 12 bilateral) were enrolled to have idiopathic TTS (total 31 feet). Tinel's sign was positive in 16 feet (51.6%) of TTS and four feet (10.5%) in control group. The statistically significant electrophysiological parameter was difference of sensory conduction velocity (SCV) between sural nerve and MPN. Amplitude of sensory nerve action potential and SCV of MPN were not different significantly between idiopathic TTS feet and controls. Conclusion: Bilateral development in idiopathic TTS was more common. Tinel's sign and difference of SCV between sural nerve and MPN may be helpful for the diagnosis of idiopathic TTS.

• Annals of Clinical Neurophysiology
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• v.7 no.2
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• pp.130-132
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• 2005

Isolated posterior antebrachial cutaneous (PABC) neuropathy is rare. A 62 year-old man presented with hypesthesia over the skin region of PABC nerve territory after an injection at the proximal to the lateral epicondyle. Antidromic sensory nerve conduction studies of PABC nerve was not evoked on the affected side. Our case showed that sensory nerve conduction of PABC nerve can be performed without much difficulty and that this test is useful in confirming PABC neuropathy.