Citations
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.
Citations
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.
Citations
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.
Citations
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.
Citations
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.
Citations
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.
Citations
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.
Citations
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)
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.
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)
Method: Nerve conduction studies were performed in 23 patients with chronic renal failure. We not only measured distal latencies, amplitudes, and conduction velocities of median and ulnar motor nerves but also measured same parameters of radial sensory nerves at both upper limbs. In case of pateints with suspected peripheral polyneuropathy, we checked peripheral nerves at one lower limb. The results of nerve conduction studies and the frequency of cubital tunnel syndrome or carpal tunnel syndrome were compared between arteiovenous fistula side and non-arteiovenous fistula side.
Results: The amplitudes of median motor, ulnar motor nerves and radial sensory nerve in arteiovenous fisula side are statistically lower than those in non-arteiovenous fisula side (p＜0.05). In the 14 patients with peripheral polyneuropathy, the difference is also statistically significant between two sides (p＜0.05). Compared arteiovenous fisula side with non-arteiovenous fisula side, the frequency of cubital tunnel syndrome or carpal tunnel syndrome was not different between two sides.
Conclusion: Arteiovenous fisula may damage to the peripheral nerve in patients with chronic renal failure. (J Korean Acad Rehab Med 2003; 27: 85-89)
Method: Prospectively, total 40 patients with non-insulin dependent diabetes mellitus were included in the study. NCS was performed on median, ulnar, posterior tibial, deep peroneal, superficial peroneal, and sural nerves. Distal latency and conduction velocity (CV) of compound muscle action potential (CMAP), distal latency and amplitude of sensory nerve action potential (SNAP) were used as parameters of NCS. Multiple linear regression analysis were used to analyze the relations of HbA1c and parameters of NCS, after adjustment for age, height, weight, and disease duration of diabetes mellitus.
Results: HbA1c level had an inverse relation to CV of median motor nerve (β=1.272, p＜0.01), ulnar motor nerve (β=1.287, p＜0.01), posterior tibial nerve (β=0.982, p＜0.05), and deep peroneal nerve (β=1.449, p＜0.05).
Conclusion: This study indicates that HbA1c level was inversely related to motor nerve CV, and that sustained hyperglycemia may be involved in demyelination of motor nerves. Analysis of motor nerve CV related to HbA1c is expected to be useful in the follow-up or efficacy study of diabetes mellitus neuropathy as baseline data. (J Korean Acad Rehab Med 2003; 27: 80-84)
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)
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