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To identify which combination of motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs) is most reliable for postoperative motor deterioration during spinal cord tumor surgery, according to anatomical and pathologic type.
MEPs and SEPs were monitored in patients who underwent spinal cord tumor surgery between November 2012 and August 2016. Muscle strength was examined in all patients before surgery, within 48 hours postoperatively and 4 weeks later. We analyzed sensitivity, specificity, positive and negative predictive values of each significant change in SEPs and MEPs.
The overall sensitivity and specificity of SEPs or MEPs were 100% and 61.3%, respectively. The intraoperative MEP monitoring alone showed both higher sensitivity (67.9%) and specificity (83.2%) than SEP monitoring alone for postoperative motor deterioration. Two patients with persistent motor deterioration had significant changes only in SEPs. There are no significant differences in reliabilities between anatomical types, except with hemangioma, where SEPs were more specific than MEPs for postoperative motor deterioration. Both overall positive and negative predictive values of MEPs were higher than the predictive values of SEPs. However, the positive predictive value was higher by the dual monitoring of MEPs and SEPs, compared to MEPs alone.
For spinal cord tumor surgery, combined MEP and SEP monitoring showed the highest sensitivity for the postoperative motor deterioration. Although MEPs are more specific than SEPs in most types of spinal cord tumor surgery, SEPs should still be monitored, especially in hemangioma surgery.
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To evaluate whether the combination of muscle motor evoked potentials (mMEPs) and somatosensory evoked potentials (SEPs) measured during spinal surgery can predict immediate and permanent postoperative motor deficits.
mMEP and SEP was monitored in patients undergoing spinal surgery between November 2012 and July 2014. mMEPs were elicited by a train of transcranial electrical stimulation over the motor cortex and recorded from the upper/lower limbs. SEPs were recorded by stimulating the tibial and median nerves.
Combined mMEP/SEP recording was successfully achieved in 190 operations. In 117 of these, mMEPs and SEPs were stable and 73 showed significant changes. In 20 cases, motor deficits in the first 48 postoperative hours were observed and 6 patients manifested permanent neurological deficits. The two potentials were monitored in a number of spinal surgeries. For surgery on spinal deformities, the sensitivity and specificity of combined mMEP/SEP monitoring were 100% and 92.4%, respectively. In the case of spinal cord tumor surgeries, sensitivity was only 50% but SEP changes were observed preceding permanent motor deficits in some cases.
Intraoperative monitoring is a useful tool in spinal surgery. For spinal deformity surgery, combined mMEP/SEP monitoring showed high sensitivity and specificity; in spinal tumor surgery, only SEP changes predicted permanent motor deficits. Therefore, mMEP, SEP, and joint monitoring may all be appropriate and beneficial for the intraoperative monitoring of spinal surgery.
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To establish a supraorbital nerve sensory conduction recording method and assess its usefulness.
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.
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.
We have successfully recorded supraorbital SNAPs. This conduction technique could be quite useful in evaluating patients with supraorbital nerve lesions.
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Although spinal cord injury without radiographic abnormality (SCIWORA) literally refers to the specific type of spinal cord injury, however, some extents of spinal cord injuries can be detected by magnetic resonance imaging (MRI) in most of cases. We introduce an atypical case of spinal cord injury without radiologic abnormality. A 42-year-old male tetraplegic patient underwent MRI and computed tomography, and no specific lesions were found in any segments of the spinal cord. Moreover, the tetraplegic patient showed normal urodynamic function despite severe paralysis and absent somatosensory evoked potentials from the lower limbs.
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Acute transverse myelitis (ATM) is an upper motor neuron disease of the spinal cord, and concomitant association of peripheral polyneuropathy, particularly the axonal type, is rarely reported in children. Our cases presented with ATM complicated with axonal type polyneuropathy. Axonal type polyneuropathy may be caused by acute motor-sensory axonal neuropathy (AMSAN) or critical illness polyneuropathy and myopathy (CIPNM). These cases emphasize the need for nerve and muscle biopsies to make the differential diagnosis between AMSAN and CIPNM in patients with ATM complicated with axonal polyneuropathy.
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To evaluate whether an initial complete impairment of spinal cord injury (SCI) contributes to the functional outcome prediction, we analyzed the relationship between the degree of complete impairment according to the American Spinal Injury Association impairment scale (AIS), the posterior tibial nerve somatosensory evoked potential (PTSEP) and the changes of functional indices.
Sixty subjects with SCI were studied who received rehabilitative management for over 2 months. The degree of completeness on basis of the initial AIS and PTSEP were evaluated at the beginning of rehabilitation. Following treatment, several functional indices, such as walking index for spinal cord injury version II (WISCI II), spinal cord independence measure version III (SCIM III), Berg Balance Scale (BBS), and Modified Barthel Index (MBI), were evaluated until the index score reached a plateau value.
The recovery efficiency of WISCI and BBS revealed a statistically significant difference between complete and incomplete impairments of initial AIS and PTSEP. The SCIM and MBI based analysis did not reveal any significant differences in terms of the degree of AIS and PTSEP completeness.
AIS and PTSEP were highly effective to evaluate the prognosis in post-acute phase SCI patients. BBS and WISCI might be better parameters than other functional indices for activities of daily living to predict the recovery of the walking ability in post-acute SCI.
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To investigate the predictive index of functional recovery after primary pontine hemorrhage (PPH) using the combined motor evoked potential (MEP) and somatosensory evoked potential (SEP) in comparison to the hematoma volume and transverse diameter measured with computerized tomography.
Patients (n=14) with PPH were divided into good- and poor-outcome groups according to the modified Rankin Score (mRS). We evaluated clinical manifestations, radiological characteristics, and the combined MEP and SEP responses. The summed MEP and SEP (EP sum) was compared to the hematoma volume and transverse diameter predictive index of global disability, gait ability, and trunk stability in sitting posture.
All measures of functional status and radiological parameters of the good-outcome group were significantly better than those of the poor-outcome group. The EP sum showed the highest value for the mRS and functional ambulatory category, and transverse diameter showed the highest value for "sitting-unsupported" of Berg Balance Scale.
The combined MEP and SEP is a reliable and useful tool for functional recovery after PPH.
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To investigate the somatosensory findings of pusher syndrome in stroke patients.
Twelve pusher patients and twelve non-pusher patients were enrolled in this study. Inclusion criteria were unilateral stroke, sufficient cognitive abilities to understand and follow instructions, and no visual problem. Patients were evaluated for pusher syndrome using a standardized scale for contraversive pushing. Somatosensory finding was assessed by the Cumulative Somatosensory Impairment Index (CSII) and somatosensory evoked potentials (SEPs) at 1 and 14 weeks after the stroke onset. Data of SEPs with median and tibial nerve stimulation were classified into the normal, abnormal, and no response group.
In the baseline characteristics (sex, lesion character, and side) of both groups, significant differences were not found. The score of CSII decreased in both groups at 14 weeks (p<0.05), but there were no significant differences in the CSII scores between the two groups at 1 and 14 weeks. There were no significant differences in SEPs between the two groups at 1 and 14 weeks after the stroke onset.
It appears that somatosensory input plays a relatively minor role in pusher syndrome. Further study will be required to reveal the mechanism of pusher syndrome.
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To evaluate the prevalence and risk factors of peripheral neuropathy in patients with rheumatoid arthritis (RA) treated with leflunomide (LEF) by quantitative sensory testing (QST).
A total of 94 patients were enrolledin this study, out of which 47 patients received LEF. The other 47 patients received alternative disease-modifying antirheumatic drugs and served as the control group. The demographic characteristics, laboratory findings, concomitant diseases, and medication history were evaluated at the time of QST. The cooling (CDT) and vibratory detection threshold (VDT) as the representative components of QST were measured.
Age, gender, RA duration, ESR, and CRP did not show any significant differences between the two groups. VDT did not demonstrate any significant difference in both groups. However, CDT in LEF group was significantly higher than that of the control group (8.6±2.7 in LEF vs. 5.6±3.8 in control). The proportion of RA patients in the LEF group showing abnormally high CDT was over 2 times greater than that of the control group, but these findings were not statistically significant. Age, RA duration (or LEF medication in LEF group), ESR, and CRP did not show significant correlation with CDT in both groups. VDT significantly correlated with age in both groups.
LEF treatment in patients with RA may lead to abnormal CDT in QST. CDT value was not affected by age, RA duration, disease activity, or LEF duration. It remains to be determined whether QST may be a valuable non-invasive instrument to evaluate the early sensory changes in patients with RA taking LEF.
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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.
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Objective: Intraoperative monitoring using somatosensory evoked potential (SEP) study has been used increasingly to monitor neurological function during scoliosis surgery and other high-risk spinal surgeries. However, there are few studies related to this intraoperative monitoring, particularly in severe spinal deformity surgery, in Korea. So we evaluated the clinical efficacy of intraoperative SEP monitoring and considered the risk factors related to spinal surgery.
Method: We performed a posterior tibial nerve somatosensory evoked potential study for intraoperative monitoring during surgical procedures in 101 patients (male 46, female 55).
Results: Neurologic damage occurred in 16 patients (10 congenital scoliosis cases, 5 tuberculous kyphosis cases, and 1 degenerative spondylosis case) after surgical procedures. Delayed postoperative neurologic damage occurred in 4 patients (2 mild damage cases, 2 severe damage cases) among 85 cases which showed normal responses during surgical procedures. Sensitivity of this study was 75%, and specificity was 95.3%.
Conclusion: Somatosensory evoked potential study for intraoperaive monitoring is a sensitive and very useful method to detect iatrogenic lesions during spinal deformity surgery with satisfactory specificity. However, to improve the sensitivity and specificity of the intraoperative monitoring, combination of motor evoked potentials is recommended.
The purpose of this study was to investigate the maturation characteristics of neonates.
Ninety three neonates underwent a somatosensory evoked potentials(SEPs) testing. Twenty four point seven percent of them were neonates at risks including the neonatal asphyxia, low birth weight under 1500 g, or a suspicious CNS abnormality.
Seventy five point three percent of neonates showed normal median SEPs, and 24.7% of them showed abnormal or a flat response. The mean latency of the first cortical component(N1) was 25.3⁑5.4 msec, duration 16.3⁑5.5 msec and amplitude 1.00⁑1.27 ㄍV.
Thirty one point two percent of neonates showed normal posterior tibial SEPs, and 68.8% showed abnormal or a flat response. The mean latency of the first cortical component(P1) was 44.9⁑5.6 msec, duration 17.5⁑3.9 msec and amplitude 0.47⁑0.38 ㄍV.
This result suggests that the maturation of rostal nervous system develops earlier than the caudal system.
Linear decrease of the cortical latency with post-menstrual age reflects maturation of the central pathway and not merely maturation of the peripheral nerves. But our study showed much less frequency of recordings of the tibial nerve SEPs than the median nerve responses, which suggested that the maturation of spinal cord and lower-limb nerves would be slow, in addition to that the length of pathway was increasing. This result suggests that the maturation of the proximal shorter nervous pathway develops earlier than the distal longer pathway.
Objective: This study was performed to investigate the prognostic value of multi-sensory evoked potentials (MSEPs) in neonatal period for the early diagnosis of delayed motor development, especially cerebral palsy.
Method: The MSEPs studies composed of auditory brainstem evoked potentials (AEPs), visual evoked potentials (VEPs) and somatosensory evoked potentials were taken on 237 neonates, 136 boys and 101 girls, using Viking IVⰒ machine. Follow up MSEPs were repeated in every 4 or more weeks for those who showed abnormal responses in any of the MSEPs. Each neonate was also evaluated for motor development as an outpatient or by telephone interview.
Results: Among 237 neonates, 6.4% showed delayed development, and 4.6% were cerebral palsy: 3.8%, spastic type; 0.8%, athetoid type, and the others revealed normal motor development. AEP was useful method to predict motor development when this was done at 39.7⁑0.4 weeks of postmenstrual age (PMA). VEPs failed to show the validity, but there was the typical waveform change in accordance with increase of the postmenstrual age. Median nerve SEPs were valuable for prediction of motor development which were taken at PMA 40.7⁑0.6 weeks. After 45.3⁑1.5 weeks of PMA, median nerve SEPs did not reflect motor development outcome significantly. However, posterior tibial SEPs significantly reflect motor outcome regardless of the time of examination.
Conclusion: Median and posterior tibial SEPs done before 40weeks of PMA are useful tool to predict motor development outcome. When any of these tests showed abnormal findings, follow up study is recommended and posterior tibial SEP study is thought to be the most useful for its predictability. It is necessary to correlate the AEPs and VEPs with hearing and vision whenever abnormal findings are found.
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 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: We measured current perception threshold (CPT) with transcutaneous electrical nerve stimulation (TENS) to prove the selective increment of the threshold of C sensory fiber and to determine onset time and duration of effect for application of TENS.
Method: TENS were applied to fifteen control volunteers for 20 minutes on hand three times per week for 2 weeks duration. The CPT was tested at the distal interphalangeal joint of the second finger with 5 Hz, 250 Hz, and 2,000 Hz in frequency, respectively. The test was repeated immediately and 30 minutes after cessation of TENS. These tests were performed on the first, eighth, and fifteenth day on application of TENS.
Results: The baseline CPT of C fiber was 32.7⁑6.4 102 mA, Aδ fiber 23.2⁑9.4 102 mA, and Aβ fiber 83.9⁑18.1 102 mA. At 30 minutes after cessation of TENS in the fifteenth day, the CPT of C fiber increased markedly and that of Aδ fiber increased a little. The CPT of Aβ fiber didn't increase for 2 weeks.
Conclusion: With application of TENS, the threshold of C and Aδ fibers selectively increased, especially 30 minutes after removal of TENS application. This effect was outstanding after 2 weeks' application. (J Korean Acad Rehab Med 2002; 26: 161-166)
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.
This prospective study following American Association of Electrodiagnostic Medicine recommended criteria in the diagnosis of Carpal Tunnel Syndrome(CTS) evaluated the sensitivity of multi-electrodiagnostic parameters and usefulness of residual latency in CTS.
In 45 symptomatic hands of 26 patients with clinical diagnosis of CTS, 8 electrodiagnostic parameters-median motor distal latency, median motor residual latency, median sensory onset latency, median sensory peak latency, median to ulnar sensory onset latency difference(digit 4), median to ulnar sensory peak latency difference(digit 4), median to radial sensory onset latency difference(digit 1), median to radial sensory peak latency difference(digit 1)-were compared to the normative data obtained from the age-matched control group.
In 31 CTS hands without polyneuropathy, median to ulnar sensory latency difference(digit 4), median to radial sensory latency difference(digit 1), median sensory peak latency have same sensitivity(71.0%).
In 8 CTS hands with delayed proximal median motor nerve conduction velocity which were indiscernible from polyneuropathy in routine nerve conduction study, residual latency was more sensitive than median to ulnar sensory latency difference and median to radial sensory latency difference.
Sensitivity difference between sensory onset latency and sensory peak latency was negligible in the electrophysiologic diagnosis of CTS.
We concluded that residual latency measurement was a very useful and convenient method in the diagnosis of CTS, especially in the patients with delayed proximal median motor conduction velocity.
The central somatosensory conduction time(CCT) was measured by recording the cerebral and spinal evoked potentials following median nerve stimulation in 24 traumatic brain injury patients. The findings of evoked potential study correlated to the functional independence measure(FIM), mini mental status examination(MMSE) and Glasgow outcome scale(GOS).
The CCT of head injured patients was prolonged compared to that of the controls. The CCT with stimulation of the affected side was significantly prolonged compared to that with non- affected side. Abnormal CCT was related to the poor functional status measured by FIM and GOS. There`s no significant difference between groups of absent evoked potential and prolonged CCT by FIM score.
These results suggest that the CCT correlates with the functional status of head injured patients. Follow up studies are required to evaluate whether the CCT could be a valuable prognostic indicator or not.
Method: Thirty eight complete peripheral nerve injuries, diagnosed by motor and sensory nerve conduction studies (NCS) and needle electromyography (nEMG), were studied. Nerve injuries were grouped into two groups with and without SEP recorded at the time of initial evaluation. Outcome of nerve injuries was graded from 0 to 3 based on the results of NCSs and nEMG, followed up for more than six months. Grade 0 was designated for those with no evidence of recovery, and grade 3 for those with recovery in nEMG and both motor and sensory NCSs.
Results: At the time of initial electrodiagnosis, SEP study showed no response in 25 cases, but SEP could be observed in 13 cases, although they were attenuated or delayed. Recovery of nerve injury was observed in 22 cases, despite the findings compatible with complete injury in initial NCSs and nEMG. The group in which SEPs were recorded showed significantly higher grades of recovery, compared to no re sponse group.
Conclusion: In predicting the prognosis of complete peripheral nerve injuries, SEP study could be useful as a supplementary electrodiagnostic method.
Objective: To obtain normal data of quantitative sensory test (QST) in Korean adult.
Method: The subjects were 85 normal adults aging from 30 to 69 years old, who had no abnormal sensory and neurologic problem. We performed following three QSTs on dominant side and one verbal questionnaire. 1) Semmes-Weinstein monofilament wire system (0.05 G, 0.2 G, 2 G, 4 G, 10 G, 300 G) for touch sensation, 2) Rydel-Seiffer Tuning Fork for vibration sensation, 3) TSA-2001 Thermal sensory analyser for thermal sensation, 4)University of Texas Subjective Peripheral Neuropathy verbal questionnaire.
Results: 1) Touch perception score measured with Semmes-Weinstein monofilament wire system, declined with age (p＜0.01). 2) Vibration perception score measured with the tuning fork, declined with age in foot (p＜0.01). 3) Warm sense and heat pain threshold measured with TSA-2001 thermal sensory analyser increased with age, and cold sense and cold pain threshold declined with age. 4) Weight showed negative correlation with vibration perception score in man's foot.
Conclusion: Normal data of three sensory test obtained from this study could be used for the early detection of peripheral neuropathy or loss of "protective sensation".
Pudendal nerve somatosensory evoked potential(PSEP) study has been utilized for the evaluation of neurogenic dysfunctions of bowel, bladder and sex. However, the reluctance of sexual organ exposure during the study can be a serions limiting factor. Sacral dermatomal somatosensory evoked potential(SDSEP) study stimulating sacral dermatome can be an alternative or a supportive method for the PSEP study.
The purpose of this study is to present the techniques, normal values and clinical significance of SDSEP study in spinal cord injured patients. Thirty control subjects and thirty-five spinal cord injured patients were enrolled for the study. Using ring electrodes, S3 dermatome was stimulated by Nicolet Viking IV EMG/EP system. Evoked responses were recorded at the cortex(Cz'-Fz) by the needle electrodes. The latencies and amplitudes of SDSEP and PSEP responses were obtained and analyzed. In control subjects, the P1 latencies of SDSEP were 34.72⁑2.68 msec for the right and 33.54⁑1.95 msec for the left. The N1 latencies were 43.06⁑2.31 msec for the right and 42.14⁑2.29 msec for the left, respectively. The P1N1 amplitudes of control subjects were 0.73⁑0.40 ㄍV for the right and 0.69⁑0.22 ㄍV for the left. The coincidence of SDSEP and PSEP was 86.7% of the spinal cord injured patients.
In conclusion, SDSEP study could be used for the evaluation of neurogenic dysfunctions of bladder, bowel, and sex in conjunction with the PSEP study.
Objective: The purpose of this study is to evaluate the relationship between cognitive function and findings of evoked potential study in chronic renal failure patients.
Method: Thirty chronic renal failure patients with cognitive dysfunction were recruited, whose mini-mental state examination (MMSE) scores were less than 24 points. According to the underlying diseases of chronic renal failure, we categorized thirty patients into diabetic group (11 patients) and non-diabetic group (19 patients), and the control-group was composed of 15 normal volunteers. Somatosensory evoked potential (SEP) on stimulating median and posterior tibial nerves, and cortical and spinal conduction time of the motor pathways were valuated.
Results: In tibial nerve SEP, N22-P38 interpeak latencies (IPL) were 18.1⁑4.2 msec in the patient group and 15.7⁑1.9 msec in the control group, respectively. In MEP, cortico-lumbar central motor conduction times (CMCT) were 19.5⁑2.7 and 16.5⁑3.0 msec, respectively. CMCT were prolonged in patients than controls (p＜0.05). There was significant correlation between serum creatinine concentration and N22-P38 IPL (r=0.64, p＜0.05), but, there were no correlations between the underlying diseases of chronic renal failure, duration of disease, MMSE score and cortico-lumbar CMCT, N22-P38 IPL (p＞0.05).
Conclusion: Evoked potentials will be helpful in evaluating the patients with cognitive dysfunction in chronic renal failure.
Objective: To evaluate the changes of dermatomal SEP (DSEP) in children with a spastic cerebral palsy (CP) after the selective posterior rhizotomy (SPR).
Method: The subjects were 14 spastic CP children, with the age from 3 to 6 years old, who underwent SPR. DSEPs were studied at the L2-3, L4, L5, S1 dermatomes bilaterally, pre and postoperatively. Postoperative DSEPs were interpreted by the changes of latency, amplitude and waveforms.
Results: 1) All children were spastic diplegia except one who was a spastic hemiplegia. 2) Preoperative DSEPs were flat or severely distorted in 40 of 112 waveforms (34.5%). 3) Postoperative DSEP latencies were no change in 39.3%, improved in 17.9%, and worsened in 25.6% respectively. Amplitudes were no change in 30.8%, improved in 38.5%, and worsened in 13.7% respectively. Waveforms were no change in 64.1%, improved in 22.2%, and worsened in 8.5% respectively. There was no statistical difference of postoperative changes of the 3 categories according to the root levels.
Conclusion: The results showed that the preoperative DSEPs were abnormal in 34.5% suggestive the lesions of CP being more widespread than strictly involving the motor system. This study confirmed that the most SEPs unchanged by the SPR. A further study for the relationship of postoperative DSEP changes and clinical findings such as functional impairment would be needed.
This 32 year-old man sustained crush injury and resultant in paraplegia. Lumbar MRI was taken and revealed fracture and dislocation between L2 and L3 vertebrae bodies. On the day of the injury, he underwent a surgical intervention of posterolateral fixation and bone graft from L1 to L4 vertebrae. He was transferred to Rehabilitation Medicine Department of Asan Medical Center where patient was subsequently found to have an unexpected neurologic finding of decreased sensation below T5 dermatome on right and below T6 on left. Accordingly we took a thoracic MRI which showed features consistent with arachnoiditis at thoracic and lumbar cord segment. A dermatomal somatosensory evoked potential study was performed with finding of abnormal somatosensory pathway below mid thoracic dermatome. We reported an unusual case of thoracic arachnoiditis occurred after the surgical fixation of the lumbar vertebral fracture and dislocation.
This study was designed to verify the validity of bulbocavernosus reflex latency(BCRL) and pudendal somatosensory evoked potential(SEP) in the evaluation of neurogenic erectile dysfunction and to lay out a scheme to uplift the diagnostic accuracy of BCRL and pudendal SEP. Eighty four subjects who were referred to Seoul National University Hospital EMG laboratory for the evaluation of the erectile dysfunction were examined. At first, history taking, physical examination, measurement of serum hormone level, rigiscan with audiovisual sexual stimulation were performed. In the next step, intracorporial papaverine injection, nocturnal penile tumescence test, BCRL and pudendal SEP were performed as indicated. Then the results of BCRL and pudendal SEP were compared to the final diagnosis obtained through additional studies. Psychogenic cause was most common and neurogenic, vascular, and hormonal causes followed. The diagnostic sensitivity of BCRL and pudendal SEP in the discrimination of neurogenic cases from nonneurogenic cases was 89.5% and 93.7%, respectively. The specificity was 89.7% and 64.7% in order. Among twenty seven subjects with abnormal BCRL or pudendal SEP, eight subjects were confirmed as psychogenic impotence at the final diagnosis. But psychogenic impotence was not found among nine subjects who had abnormal BCRL and pudendal SEP. Twenty three subjects with abnormal BCRL were divided into delayed latency group and no response group. Among thirteen subjects of delayed latency group, psychogenic cases were six and among ten subjects of no response group, psychogenic case was not found. In the evaluation of neurogenic impotence, BCRL was a sensitive and specific tool while pudendal SEP was sensitive but less specific. BCRL alone or pudendal SEP alone would be inadequate for the evaluation of neurogenic impotence, especially in discrimination with psychogenic one. To improve diagnostic accuracy in the evaluation of impotence, BCRL and pudendal SEP should be checked out all together. In the situation when only BCRL is available, it is recommendable to take unevokable bulbocavernosus reflex as meaningful.
Polyneuropathy is a common complication of chronic renal failure and usually remains stable or improves with hemodialysis. The purpose of this study was to investigate the usefulness of somatosensory evoked potential(SEP) study for the evaluation of polyneuropathy in chronic renal failure(CRF) patients who were on hemodialysis. The clinical findings, conventional nerve conduction study and SEP study were analyzed and compared in 30 patients with chronic renal failure before and after hemodialysis. Abnormal electrophysiological findings were shown in 25 patients(83.3%) of whom 8 patients showed abnormal somatosensory evoked potential(SEP) study only. Therefore it would be useful to perform both the somatosensory evoked potential(SEP) study and conventional nerve conduction study(NCS) for the evaluation of polyneuropathy. Improvement of somatosensory evoked potential(SEP) finding is correlated well with that of clinical symptoms after hemodialysis.
Therefore, somatosensory evoked potential(SEP) study can be used to monitor with progression of polyneuropathy in patients with chronic renal failure(CRF) who were on hemodialysis.
The effect of electrical nerve stimulation are controversial because of the inconsistent variables of stimulating current and electrophysiologic study. The purposes of this study are to reconfirm the electrophysiolgic changes by electrical stimulation of the peripheral nerve that had been reported in 1993, and to monitor how long they will be maintained. In this study, the following conditioning stimulations were applied to 20 healthy volunteers; interferential current(frequency: 80∼100 Hz, intensity: 27∼34 mA) on the sacral paraspinal area. The H reflex, the F response, and the somatosensory evoked potential(SEP) of the tibial nerve were evaluated as the electrophysiologic study before, immediately after, 30 minutes, 60 minutes, and 120 minutes after the above conditioning stimulation. The following results were obtained;
1) Latencies of the H reflex, the F response and the SEP(P1), and the F wave conduction time, the F wave conduction velocity and the F ratio in the tibial nerve conduction study were increased by conditioning stimulation of the proximal peripheral nerves(P＞0.01).
2) Changes of the amplitude of the H reflex, the H/M ratio, and the amplitude(P1N1) of the tibial SEP were not significant in the same conditioning stimulation(P＞0.05).
3) Prolongations of the latencies of H reflex, F response and P1 SEP of the tibial nerve were the most significant immediately after conditioning stimulation and sustained for 45 minutes after conditioning on average (P＜0.01).
The above results suggest that certain conditional electrical stimulation of the peripheral nerves causes reversible changes in the conduction of the H reflex, the F response and the SEP and they may be inhibitory effect of the proximal conduction via the spinal cord.
Objective: To evaluate the diagnostic values of segmental somatosensory evoked potentials (SEPs) in the unilevel/unilateral lumbosacral radiculopathies.
Method: Thirty-nine radiculopathy patients of whom diagnosis was confirmed by the surgery or selective nerve root injection and 20 subjects with no evidence of radiculopathy were included in the study. Before the treatment, superficial peroneal nerve segmental SEPs and sural nerve segmental SEPs were performed. Sensitivities and specificities were delineated from the several diagnostic criteria.
Results: The analysis of side-to-side mean cortical P1 latency difference (＞2.0 SD) reveals a segmental SEPs sensitivity for L5 radiculopathies of 12.1% and sensitivity for S1 radiculopathies of 0%. The analysis of side-to-side mean percent amplitude difference (2.0 SD) reveals a segmental SEPs sensitivity for L5 radiculopathies of 9.1% and sensitivity for S1 radiculopathies of 0%. The analysis of side-to-side mean cortical P1 latency difference (＞3 ms) and the side-to-side mean amplitude reduction (＞50%) show the similar results. The specificities of L5 radiculopathies and S1 radiculopathies are variable from 40.0% to 93.3%. Sensitivities of segmental SEPs are lower than needle EMG. It is not root specific, even the SEP is not obtainable unilaterally.
Conclusion: The diagnostic values of segmental somatosensory SEPs are questionable in the unilevel/unilateral lumbosacral radiculopathies which are confirmed by the surgery or selective nerve root injection.
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. (J Korean Acad Rehab Med 2003; 27: 480-484)
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.
We report a 13 year-old female child with a idiopathic acute sensory neuronopathy mimicking a sensory form of Guillain-Barré syndrome, identified with electrodiagnosis and spine MRI. Motor conduction results were normal, but sensory nerve action potentials were not evoked in all four extremities. On MRI of the whole spine, the diffuse gadolinium-enhancement of dorsal roots in the spinal canal was detected without evidence of intramedullary lesion. The clinical symptoms and electrodiagnostic abnormalities had persisted for more than 18 months follow-up.
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