To perform nerve conduction studies of the four branches of the superficial peroneal nerves to determine normal values and anatomic variations in Koreans.
Antidromic sensory nerve conduction studies of the four distal branches were performed on 70 healthy subjects (100 feet). We applied electrical stimulation at the midpoint of medial and lateral malleoli for the medial dorsal cutaneous nerve (MDCN), and at the lateral 1/4 point between the medial and lateral malleoli for the 2 branches of the intermediate dorsal cutaneous nerve (IDCN).
Reference values (mean±SD) of the onset/ peak latency (ms)/ sensory action potential amplitude (µV) for the two branches of the MDCN and for the first branch of the IDCN were 2.2±0.3/2.9±0.3/9.2±3.1, 2.2±0.3/2.8±0.3/9.1±3.0 and 2.3±0.4/2.9±0.3/8.5±2.8, respectively. For the second IDCN branch, the reference values were 2.3±0.4/3.0±0.4/7.1±2.6 but anomalous sural innervation was also found. Three types of IDCN innervations to the fourth interdigital web space were detected. In type I, the fourth interdigital webspace was innervated solely by the IDCN, whereas in type II, it was innervated by both the IDCN and distal sural nerve. In type III, it was solely innervated by the distal sural nerve.
The results of this study show the reference values of the distal sensory branches of the superficial peroneal nerve, and provide information on the variant innervations to the fourth interdigital web space.
Citations
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: To establish the posterior cutaneous nerve of arm (PCNA) conduction technique and set up the reference values.
Method: A PCNA conduction study was performed in 80 nerves of 40 neurologically healthy adult subjects with a mean age of 38 years (range, 20 to 56). Dantec Counterpoint MK2 machine was used. The recording bar electrodes were placed 10 cm distal to the axillary fold on a line connecting the posterior axillary fold and the olecranon. Supramaximal stimulation was applied to the axilla posterior to the brachial artery. Onset latency, baseline to peak amplitude and negative spike duration of sensory nerve action potentials were obtained. Skin temperature was measured in the posterior arm and maintained at 34oC or above.
Results: Compound sensory action potential for the PCNA was recordable in all the subjects. The results were as follows: onset latency, 1.7⁑0.1 msec; baseline to peak amplitude, 4.6⁑1.4μV; negative spike duration, 1.1⁑0.2 msec.
Conclusion: PCNA response is readily obtainable. This study may help to assess the pain or paresthesia in the posterior aspect of the arm, although more studies are required for clinical application.
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.
Objective: To investigate the influence of five different recording electrodes on the various parameters of sensory nerve action potentials (SNAPs).
Method: Median sensory nerve conduction study was performed in 50 normal subjects using different five types of recording electrodes-disc electrode, ring electrode, bar electrode and two kinds of felt-tip bar electrodes (type 1 and 2). The interelectrode distances between active and reference electrodes were set at 4 cm for the disc and ring electrodes. The bar electrode, felt-tip electrodes type 1 and 2 were fixed at interelectrode distances of 3 cm, 3.7 cm and 2.3 cm, respectively. Onset and peak latency, onset to peak amplitude, peak to peak amplitude and duration of negative spike of SNAPs were measured. These parameters were compared using ANOVA test.
Results: Onset and peak latencies of SNAPs recorded from five different electrodes were not different (p＞0.05). Onset to peak and peak to peak amplitudes of SNAPs recorded from felt-tip type 2 electrode were significantly reduced compared to other electrodes (p＜0.05). Onset to peak amplitude of SNAPs was also reduced when the ring electrode was used (p＜0.05). The negative spike durations of SNAPs recorded from felt-tip type 2 and bar electrodes were shorter than other electrodes recording (p＜0.05).
Conclusion: Onset and peak latencies of SNAPs were not affected by the types of electrodes used. Shortening of interelectrode distance may be a main cause of reduction of peak to peak amplitude and negative spike duration of SNAPs.
Objective: To establish the reference values of the sensory conduction for all the digits in the hand, conduction studies were performed using the standard technique.
Method: One hundred hands of fifty neurologically healthy adults with mean age of 45 years (range, 23∼69) were tested. Depending on ages, the 50 adults were devided into three groups: group 1, 20∼45 years old; group 2, 46∼60 years old; group 3, 61∼ years old. Antidromic sensory nerve conduction techniques using a fixed distance were performed. The onset latency and baseline to peak amplitude of the sensory nerve action potentials (SNAPs) were measured. During the test, the skin temperature of the hand was maintained at 34oC or above. These variables from SNAPs were compared according to age, gender, side, and recording digits.
Results: Comparison of the median and ulnar SNAPs between age groups revealed longer onset latency and smaller amplitude in the elderly group. The amplitude of SNAPs was larger in females than in males and the left side than the right side. Comparison of the latencies and amplitudes between the second and third digits showed no significant difference statistically. Also, the latencies and amplitudes of the median and ulnar nerves recorded from the fourth digits showed no significant difference statistically.
Conclusion: Based on these results, the reference values for sensory conductions from all the digits were obtained. These values would be helpful in evaluation of CTS or unspecified finger pain or upper extremity neuropathy.
Objective: To evaluate the usability of near-nerve needle recording techniques in cases of unrecordable sensory nerve action potentials (SNAPs) with a surface electrode and to determine a proper alternative value of the missing latencies.
Method: Twenty six hands of 23 patients with a carpal tunnel syndrome (CTS) and an unobtainable median SNAP by surface electrode were evaluated by the near-nerve needle recording of median SNAPs. Using the nerve conduction data of 113 patients with CTS, we have established 3 alternative values: maximal, 95 percentile and predictive latencies. The alternative values were compared with the mean onset latencies by the near-nerve needle recordings of median SNAPs.
Results: Median SNAPs were obtainable in the 22 out of 26 hands by the near-nerve recording technique. The mean onset latency was 5.51⁑0.36 ms. The alternative values from 113 patients with CTS were as follows: maximum latency, 6.9 ms; 95 percentile latency, 5.6 ms; and predictive latency, 5.52 ms (Y = 0.123* X 5.52491; Y, onset latency; X, amplitude; r2=0.564; p=0.00). The Predictive latency was nearest to the mean onset latency.
Conclusion: To minimize the selection bias and statistical errors, the near nerve recording techniques proved to be a valuable method in cases of unrecordable SNAPs with surface electrode. For compensation of missing data, a proper alternative value can be obtained by the predictive latency calculated from a linear regression.
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.
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