Reappraisal of Supraorbital Sensory Nerve Conduction Recordings: Orthodromic and Antidromic Techniques

OBJECTIVE: To establish a supraorbital nerve sensory conduction recording method and assess its usefulness. METHODS: Thirty-one healthy subjects without a history of trauma or neurological disease were recruited. For the orthodromic procedure, the recording electrode was attached immediately superior to the supraorbital notch. The stimulation electrode was placed on points along the hairline which evoked the largest sensory nerve action potentials (SNAPs). The antidromic sensory response was recorded after switching the recording and stimulating electrodes. The measured parameters were onset latency, peak latency, and baseline to peak amplitude of the SNAPs. The electrophysiological parameters of the bilateral supraorbital nerves were compared. We also recruited two patients who had sensory deficits on one side of their foreheads because of laceration injuries. RESULTS: The parameters of orthodromically recorded SNAPs were as follows: onset latency 1.21±0.22 ms (range, 0.9-1.6 ms), peak latency 1.54±0.23 ms (range, 1.2-2.2 ms), and baseline to peak amplitude 4.16±1.92 µV (range, 1.4-10 µV). Those of antidromically recorded SNAPs were onset latency 1.31±0.27 ms (range, 0.8-1.7 ms), peak latency 1.62±0.29 ms (range, 1.3-2.2 ms), and baseline to peak amplitude 4.00±1.89 µV (range, 1.5-9.0 µV). There was no statistical difference in onset latency, peak latency, or baseline to peak amplitude between the responses obtained using the orthodromic and antidromic methods, and the parameters also revealed no statistical difference between the supraorbital nerves on both sides. CONCLUSION: We have successfully recorded supraorbital SNAPs. This conduction technique could be quite useful in evaluating patients with supraorbital nerve lesions.

Anatomical Considerations of Lateral and Medial Antebrachial Cutaneous Nerves

OBJECTIVE: To evaluate the anatomic course of the lateral antebrachial cutaneous nerve (LABCN) and medial antebrachial cutaneous nerve (MABCN) in the forearm. METHOD: We dissected 29 upper extremities of 16 cadavers for LABCN and 20 upper extremities of 15 cadavers for the MABCN. We measured the distance (BT_L) between the biceps tendon (BT) and LABCN on the intercondylar line. The BT is the point at which biceps tendon crosses intercondylar line. The distance (L12) between LABCN and the point of 12 cm distal to BT on the line between BT and radial artery at wrist was measured. The distance (ME_M) between MABCN and medial epicondyle on the intercondylar line was measured. M8 and M10 are the distances between MABCN and the points 8 cm and 10 cm distal to BT on the line from BT to mid-point of flexor carpi radialis and palmaris longus at the wrist respectively. RESULTS: BT_L and L12 were 1.4+/-3.7 mm and 4.4+/-3.7 mm respectively. ME_M, M8 and M10 were 28.6+/-6.9 mm, 18.9+/-8.9 mm and 18.3+/-8.2 mm respectively. The thickness of LABCN and MABCN was 19.1+/-4.9 mm and 13.2+/-4.2 mm respectively. CONCLUSION: The LABCN was emerge just lateral to biceps tendon at the elbow and ran down to radial artery. The anatomic course of MABCN was variable at the elbow and forearm.

Abductor Digiti Minimi and First Dorsal Interosseous Recordings for the Localization of Ulnar Neuropathy at the Elbow

OBJECTIVE: To compare abductor digiti minimi (ADM) recording with first dorsal interosseous (FDI) recording for the localization of ulnar neuropathy at the elbow. METHOD: The subjects were consisted of 28 patients of ulnar neuropathy at the elbow. The subjects were divided into 3 groups: focal demyelination; focal demyelination and axonal degeneration; axonal degeneration. Compound muscle action potentials were recorded from both ADM and FDI muscles and ulnar nerve was stimulated at the wrist, 2 cm distal and 8 cm proximal to the medial epicondyle. Focal demyelination were analyzed into conduction block and/or conduction slowing. RESULTS: Conduction block was observed in 13 out of 28 patients (46%) with FDI recording and 11 out of the 28 patients (39%) with ADM recording. Conduction block was found solely with FDI recording in 3 patients, whereas 1 patient showed conduction block with ADM recording only. Concomitant segmental motor conduction slowing was observed in 11 out of 13 patients with FDI recording and in 6 out of 11 patients with ADM recording. CONCLUSION: Measurements to the FDI had a higher yield of abnormality than the ADM. In some patients, only one recording muscle showed abnormal findings. Therefore, it may be useful to record from both muscles to localize ulnar neuropathy at the elbow.

Frequency of Carpal Tunnel Syndrome acoording to the Severity of Diabetic Neuropathy

OBJECTIVE: To investigate the frequency of carpal tunnel syndrome (CTS) according to the severity of diabetic polyneuropathy. METHOD: Electrophysiologic study was performed in 456 patients (male 222, female 233, average age 58) with diabetes mellitus. Electrophysiologically diagnosed diabetic neuropathy was classified as suspected, probable or definite. CTS was also diagnosed both in cases with and without underlying diabetic peripheral neuropathy. The ANOVA test was used for statistical analysis. RESULTS: Out of 456 diabetic patients, 228 patients were diagnosed as diabetic peripheral neuropathy. The patients with diabetic neuropathy consisted of 107 cases (23.5%) of sus pected group, 95 cases (20.8%) of probable group and 26 cases (5.7%) of definite group. The frequencies of concomitant CTS were 49 cases (21.5%) in 228 diabetic patients without diabetic polyneuropathy, 31 cases (29%) in suspected group and 30 cases (31.6%) in probable group. These were statistically significant. However, only one case showed concomitant CTS in 26 cases of definite group. CONCLUSION: The frequency of CTS was higher in probable group compared to suspected group. However the frequency decreased in definite group because there is a difficulty in the differential diagnosis of two disease in the cases of advanced peripheral neuropathy.

Dorsal Ulnar Cutaneous Nerve Conduction Study in Entrapment Ulnar Neuropathy at the Elbow

OBJECTIVE: To evaluate the electrophysiologic findings of the dorsal ulnar cutaneous nerve (DUCN) in ulnar neuropathy at the elbow and to correlate the sensory nerve action potential (SNAP) amplitude of DUCN to those of ulnar compound muscle action potential (CMAP) and SNAP. METHOD: The subjects were 39 patients diagnosed as ulnar neuropathy at the elbow. Electrophysiologic classification consisted of 3 groups: conduction block (CB); conduction block and axonal degeneration (CBAD); axonal degeneration (AD). Findings of DUCN conduction study were evaluated according to the electrophysiologic classification. The amplitude of DUCN was correlated to those of CMAP and SNAP. RESULTS: The DUCN conduction study was normal in all cases of CB (4 cases), but was abnormal in 21 cases of CBAD (23 cases) and in 10 cases of AD (12 cases). Even in the cases with AD, 4 cases showed normal DUCN potentials. Correlations of DUCN to ulnar SNAP and CMAP were r=0.48, (p<0.01) and r=0.33, (p<0.05), respectively. CONCLUSION: Findings of DUCN may be related to the fascicular involvement of the ulnar nerve at the elbow. Although it is possible for the DUCN to be spared in ulnar neuropathy at the elbow, electrophysiologic measurement of the DUCN response remains useful, but only in those cases where it is abnormal, which suggests the lesion to be at a more proximal site.

Follow-up Study of Carpal Tunnel Syndrome with Conduction Block: Comparison between Operative and Non-operative Management

OBJECTIVE: To compare the degree of improvement of conduction block in carpal tunnel syndrome (CTS) between the patients who received operation and those who received conservative treatment. METHOD: Subjects included 33 hands of 27 CTS patients who received operation (operation group) and 20 hands of 17 patients who were managed conservatively (non-operation group). Median antidromic sensory responses were recorded with wrist and palm stimulation. The criterion for conduction block was more than 50% drop of baseline to negative peak amplitude of sensory nerve action potential with wrist stimulation compared to palm stimulation. The degree of conduction block was measured before and aftertreatment, and the improvement of conduction block was compared between the two groups. RESULTS: The degrees of conduction block were 59.9+/-14.3% in operation group and 60.5+/-14.5% in the non-operation group at initial evaluation. The improvements of conduction block were 32.1+/-15.1% (5~58.9%) in operation group and 7.8+/-19.8% (-27.3~36.7%) in non-operation group after treatment and the difference was statistically significant. CONCLUSION: The results suggest that operative treatment may be useful even in patients with carpal tunnel syndrome with conduction block.

Influence of Reflex Sympathetic Dystrophy on Functional Outcomes of the Upper Extremity in Stroke Patients

OBJECTIVE: To assess the influence of reflex sympathetic dystrophy (RSD) on functional status and recovery of the hemiplegic upper extremity in stroke patients. METHOD: Retrospective chart review was performed in 561 patients. Among 561 stroke patients, 116 subjects were recruited and classified into two groups: patient group, 43 cases with RSD; control group, 73 cases without RSD. Upper extremity function was assessed based on feeding, dressing and personal hygiene scores of the modified Barthel index at the beginning of rehabilitation treatment and at the time of discharge. Causes of stroke and length of stay were recorded. Median nerve-somatosensory evoked potential studies were performed and assessed. RESULTS: The incidence of RSD was 7.7% and the time to development of RSD was 62.3+/-34.1 days after the onset of stroke. There was no significant difference in functional status between two groups at initial and final evaluation. The upper extremity function had improved in both groups although the length of stay was longer in patient group. SSEP abnormalities were more frequent in the patient group. CONCLUSION: The presence of well-managed RSD affected neither the functional status nor the functional recovery of upper extremity in stroke patients.

Clinical Usefulness of Somatosensory Evoked Potentials in Patients with Stroke

OBJECTIVE: To assess the usefulness of the somatosensory evoked potentials in correlating with various clinical features and in predicting the functional outcome in patients with stroke. METHOD: The subjects were 57 patients with first stroke. Somatosensory evoked potential study was performed at the time of transfer to the rehabilitation department. Data of somatosensory evoked potential with median and tibial nerve stimulations were obtained and classified as normal (group 1), abnormal (group 2), and no response group (group 3). Modified Barthel index (MBI), motor and sensory functions were evaluated at the time of transfer and discharge. RESULTS: MBI score was statistically different among the 3 groups based on the findings of median and tibial nerve SSEP at the time of transfer, but not different at the time of discharge. Motor function was statistically different among the 3 groups at the time of transfer and discharge. Sensory function was statistically different among the 3 groups at the time of transfer, but not different at the time of discharge. CONCLUSION: Even though SSEP study reflects the functional status of the patients and correlates well with the findings of brain image, it has limitation in predicting outcome of the patients with stroke.

Clinical Status and Prognosis of Patients with Basal Ganglia Hemorrhage in Traumatic Brain Injury

OBJECTIVE: To assess the frequency of traumatic basal ganglia hemorrhage (TBGH) and its functional recovery in traumatic brain injury (TBI). METHOD: Three hundred two patients with TBI were retrospectively analyzed via the medical records and radiologic findings. The subjects were divided into 4 groups according to the brain lesions: extraaxial lesion (subdural hemorrhage, epidural hemorrhage, subarachnoid hemorrhage), intraaxial lesion (diffuse axonal injury, white matter hemorrhage, gray matter hemorrhage), mixed lesion, and TBGH. Statistical comparison of cause, severity and prognosis between groups. RESULTS: Mean age was 41.6 years old. The most common lesion of TBI was extraaxial lesion. The most common cause was falls (47.5%). The incidence of TBGH group was 4.7%. Although TBGH group was of longer duration of hospital stay and lower GCS than the other brain lesions, there was no significant difference in GOS score. TBGH with extraaxial or mixed lesion was of lower GCS and GOS score compared with TBGH itself or TBGH with intraaxial lesion. CONCLUSION: The associated cerebral lesion, but not TBGH itself, could be considered to be an important factor in determining severity and recovery of TBI.

Short Segment Conduction Study of Median and Ulnar Nerves in the Diagnosis of Carpal Tunnel Syndrome

OBJECTIVE: To compare the latency difference of median and ulnar sensory nerves through the wrist-palm short segment in patients with carpal tunnel syndrome (CTS). METHOD: Subjects included 68 hands of 36 carpal tunnel syndrome patients and 97 hands of 53 healthy adults with no electrophysiologic evidence of CTS. The median and the ulnar sensory responses were recorded on the third and the fifth digit using bar recording electrode, respectively. Both nerves were stimulated just proximal to the distal wrist crease and 5 cm distal to the proximal stimulation point. The latency differences between the 2 stimulation points were obtained. RESULTS: The transcarpal short segment conduction times in the control group were 1.0+/-0.1 msec and 0.9+/-0.1 msec for the median and ulnar nerves, respectively. The transcarpal short segment conduction times in the patients with CTS were 1.9+/-0.5 msec and 1.0+/-0.3 msec for the median and ulnar nerves, respectively. The transcarpal short segment conduction time difference between the median and ulnar nerves were 0.13+/-0.12 msec in the control group and 0.88+/-0.50 msec in the CTS group. The difference of transcarpal conduction of two nerves was statistically significant in comparison with the two groups. CONCLUSION: Wrist-palm short segment study of median and ulnar sensory nerve may be used adjunctively in diagnosis of mild CTS.

Comparison of Sural Nerve Amplitude and Sural/Radial Amplitude Ratio in the Electrodiagnosis of Diabetic Neuropathy

OBJECTIVE: To evaluate the usefulness of the sural/superficial radial sensory nerve action potential amplitude ratio (SRAR) in the electrodiagnosis of diabetic polyneuropathy. METHOD: Nerve conduction study was performed in 80 diabetic patients and 31 normal adults. Standard nerve conduction studies were performed. Sural nerve response was recorded with the active electrode on the posterosuperior margin of the lateral malleolus and stimulation 14 cm proximally. Superficial radial nerve response was recorded with the active on the snuffbox and stimulation 10 cm proximally. Baseline-to-peak sensory nerve action potential(SNAP) amplitudes were measured, and SRAR were obtained. The diabetic group was subdivided into an electro physiologically normal group (DMNL, n=32) and neuro pathy group (DMPN, n=48). SRAR was compared among the control (NORM, n=31), DMNL and DMPN groups. RESULTS: SRAR was 0.344 in NORM, 0.314 in DMNL and 0.145 in DMPN, respectively. SRAR showed 77.1% sensitivity and 93.8% specificity. Sural SNAP amplitude sensitivity was 85.4% and specificity, 88.7%. CONCLUSION: The relatively high specificity of SRAR indicates its usefulness in the diagnosis of diabetic polyneu ropathy. However, as the superficial radial sensory SNAP amplitude decreased significantly in the diabetic groups compared to control, the SRAR is not superior to the sural SNAP amplitude in the diagnosis of diabetic polyneuropathy.

Electrophysiologic Assessement of Axonopathy and Demyelination in Diabetic Neuropathy according to the Severity

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.si 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.

Anatomical Evaluation of Ulnar Nerve according to the Elbow Position

OBJECTIVE: To investigate the anatomy of the ulnar nerve according to the degree of elbow flexion and to obtain optimal elbow position for ulnar nerve conduction study. METHODS: Eleven elbows in nine cadavers were dissected. We estimated the 10 cm elbow segment to be the distance between 2 points, 4 cm distal and 6 cm proximal to the center of the cubital tunnel, which was determined to be the halfway point between the medial epicondyle and olecranon with elbow position in extension and 45o, 90o, 135o flexion. Anatomical measurements of the actual length of ulnar nerve, distance between medial epicondyle and ulnar nerve, and distance between medial epicondyle and olecranon were obtained in each position. The actual length of the ulnar nerve was measured between two points of the ulnar nerve closest to the landmarks of the estimated 10 cm with flexible ligature. RESULTS: The actual lengths of ulnar nerve were 10.23 cm, 10.00 cm, 9.44 cm, and 9.08 cm in elbow extension, and 45o, 90o, 135o flexion, respectively. The difference between actual length and estimated lengths were least in 45o elbow flexion (p=0.0001). The distance between medial epicondyle and olecranon increased with increasing elbow flexion (p=0.0001). However, there was no difference in the distance between medial epicondyle and ulnar regardless of the elbow position. As a result, the ulnar nerve seemed to have migrated anteriorly in the cubital tunnel with increasing elbow flexion. CONCLUSION: This study suggest that the optimal angle in ulnar nerve conduction study would be 45o flexion, under the condition that the distance measurement is through the halfway point between the medial epicondyle and olecranon.

Posterior Cutaneous Nerve of Arm Conduction Study in Healthy Adults: Reference Value

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 34 degrees C 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+/-1.4 microvolt; 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.

Comparison of Sensory Nerve Action Potential Parameters Using Different Recording Electrodes

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.

Clinical Pictures of Stroke Patients

OBJECTIVE: The present study evaluated the characteristics and natural history of stroke patients. METHOD: Seven hundred and sixty seven consecutive patients admitted through acute care facility were reviewed. All medical records including age, case fatality, risk factors and radiological findings including CT or MRI were reviewed. To investigate the activities of daily living (ADL) of stroke patients, follow-up study was done in 303 patients through telephone interview or direct contact. Stroke was subdivided into cerebral infarct, intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH). RESULTS: The proportion of stroke subtypes were infarct (45.9%), ICH (34.7%) and SAH (19.4%). The recurrence rate of stroke was higher in the infarct patient. Higher percentage of fatality was noted in the SAH patient. Higher incidence of hemorrhage was still observed compared to western country. Hypertension is the major risk factors for all stroke subtypes. But among hypertensive individuals, only 29% patients controlled the hypertension. Fifty-eight percent of stroke patients regained independent ADL. CONCLUSION: The result of this study shows the clinical pictures of stroke patients. Further research was needed to investigate the trends of stroke and control of risk factors and attention must be paid to the patients who is dependent in ADL.

Serial Electrodiagnostic Evaluation after Carpal Tunnel Release

OBJECTIVE: Patients with carpal tunnel syndrome are often refered for electrophysiologic evaluation of postoperative residual symptoms. We performed this prospective study to assess changes of the electrophysiological parameters after carpal tunnel release. METHOD: Fifty-four hands of 29 patients with electrodiagnostically confirmed carpal tunnel syndrome underwent surgical release of the transverse carpal ligament. Serial electrophysiological evaluation of the median nerve performed at 2 weeks, and 1, 3, 6 months after surgery in all patients. All the tests were performed by one electromyographer using Dantec Counterpoint machine. Median motor and sensory responses were obtained from abductor pollicis brevis and 3rd digit respectively. Repeated measure ANOVA test was done to observe the changes in each parameter on serial examination. RESULTS: The median motor latency (ML), motor amplitude (MA), sensory latency (SL) and sensory amplitude (SA) were as follows: preoperative ML (6.1 0.2 ms), MA (7.3 0.5 mV), SL (5.1 0.2 ms), SA (6.8 1.0 uV); postoperative week 2, ML (5.5 0.2 ms), MA (6.9 0.5 mV), SL (4.5 0.2 ms), SA (11.4 1.3 uV); postoperative month 1, ML (5.1 0.2 ms), MA (7.1 0.5 mV), SL (4.1 0.2 ms), SA (13.0 1.3 uV); month 3, ML (4.6 0.1 ms), MA (7.2 0.1 mV), SL (3.8 0.2 ms), SA (15.4 1.4 uV); month 6, ML (4.6 0.2 ms), MA (7.4 0.5 mV), SL (3.5 0.1 ms), SA (16.5 1.4 uV). CONCLUSION: Improvement was gradually seen up to the postoperative 3 months. However, the least amount of improvement was observed in the postoperative 3 to 6 month period.

Electronic Filter Setting Effects on Parameters of Nerve Conduction Studies

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 34degrees C 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 (p0.01). 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.

Amplitude Comparison between Sural and Distal Sural Nerves in 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.

Quantitative Motor Unit Analysis in Patients with Post-Polio Syndrome

OBJECTIVE: To investigate the clinical feature and quantitative electromyographic (QEMG) findings in the patients with post-polio syndrome (PPS). METHOD: Eleven patients who had clinical evidences of antecedent poliomyelitis were evaluated with standardized clinical history, physical examination and QEMG study. If a patient had fulfilled provisional criteria for PPS, he was regarded as PPS and six patients had fulfilled the criteria. Other patients were treated as control group with stable poliomyelitis. Manual muscle testing and needle EMG study including quantitative motor unit analysis was performed at the tibialis anterior and vastus medialis muscles. The existence of abnormal spontaneous activity and parameters of quantitative motor unit analysis, mean duration and amplitude of motor unit action potentials (MUAPs), were compared between PPS and control groups. The correlation between the muscle strength and parameters of QEMG was investigated. RESULTS: Abnormal spontaneous activities were noted in 4 out of 11 patients (36.4%) and three of these 4 patients were PPS. Mean duration and amplitude of MUAPs of tibialis anterior and vastus medialis muscles were not different significantly between the PPS and stable poliomyelitis group (p>0.05). The parameters of MUAPs were poorly correlated with muscle strength. CONCLUSION: Distribution of abnormal spontaneous activities and parameters of QEMG study were not different in PPS and stable poliomyelitis patients. QEMG study may not have additional benefit in differentiating PPS from stable poliomyelitis.