OBJECTIVETo investigate the role of short-latency somatosensory evoked potential (SSEP) in the diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP).

METHODSA total of 48 children with a confirmed or suspected CIDP and 40 healthy children were enrolled. Nerve electrophysiological examination and/or SSEP examination was performed (the children in the healthy control group only underwent SSEP examination). Four-lead electromyography was used for nerve electrophysiological examination, including at least 4 motor nerves and 2 sensory nerves. N6 (elbow potential), N13 (cervical cord potential), and N20 (cortex potential) of the median nerve and N8 (popliteal fossa potential), N22 (lumbar cord potential), and P39 (cortex potential) of the tibial nerve were observed by SSEP examination.

RESULTSAmong the 48 children with CIDP, 35 had demyelination in both motor and sensory nerves, 8 had demyelination in sensory nerves, and 5 had axonal degeneration. SSEP examination showed that 7 had conduction abnormality in the trunk of the brachial plexus and/or the posterior root and 33 had damage in the lumbosacral plexus and/or the posterior root. The 40 children with abnormal findings of SSEP examination included 8 children with affected sensory nerves and 5 children with secondary axonal degeneration who did not meet the electrophysiological diagnostic criteria for CIDP. Compared with the healthy control group, the CIDP group had significantly prolonged latency periods of N13 and N22 (P<0.05).

CONCLUSIONSSSEP can be used for the auxiliary diagnosis of CIDP, especially in CIDP children with affected sensory nerves or secondary axonal degeneration.

Axons ; physiology ; Child ; Child, Preschool ; Evoked Potentials, Somatosensory ; Female ; Humans ; Male ; Polyradiculoneuropathy, Chronic Inflammatory Demyelinating ; diagnosis ; physiopathology ; Reaction Time

OBJECTIVETo investigate the effect of electrical stimulation to sacral spinal nerve 3 (S₃ stimulation) on gastrointestinal dysfunction after spinal cord injury (SCI).

METHODSSix rabbits were taken as normal controls to record their gastrointestinal multipoint biological discharge, colon pressure and rectoanal inhibitory reflex. Electrodes were implanted into S₃ in another 18 rabbits. Then the model of SCI was conducted following Fehling's method: the rabbit S₃ was clamped to induce transverse injury, which was claimed by both somatosensory evoked potential and motion evoked potential. Two hours after SCI, S₃ stimulation was conducted. The 18 rabbits were subdivided into 3 groups to respectively record their gastrointestinal electric activities (n=6), colon pressure (n=6), and rectum pressure (n=6). Firstly the wave frequency was fixed at 15 Hz and pulse width at 400 μs and three stimulus intensities (6 V, 8 V, 10 V) were tested. Then the voltage was fixed at 6 V and the pulse width changed from 200 μs, 400 μs to 600 μs. The response was recorded and analyzed. The condition of defecation was also investigated.

RESULTSAfter SCI, the mainly demonstrated change was dyskinesia of the single haustrum and distal colon. The rectoanal inhibitory reflex almost disappeared. S₃ stimulation partly recovered the intestinal movement after denervation, promoting defecation. The proper stimulus parameters were 15 Hz, 400 μs, 6 V, 10 s with 20 s intervals and 10 min with 10 min intervals, total 2 h.

CONCLUSIONS₃ stimulation is able to restore the intestinal movement after denervation (especially single haustrum and distal colon), which promotes defecation.

Animals ; Disease Models, Animal ; Electric Stimulation ; Electrodes, Implanted ; Evoked Potentials, Motor ; physiology ; Evoked Potentials, Somatosensory ; physiology ; Gastrointestinal Tract ; physiopathology ; Rabbits ; Sacrum ; innervation ; Spinal Cord Injuries ; physiopathology

BACKGROUNDThe brain death confirmation tests occupy a different position in each country's diagnostic criteria (or guideline); the choices of tests are also different. China brain death criteria include clinical judgment and confirmation tests. This study aimed to confirm the preferred confirmatory test and complementary confirmatory tests.

METHODSWe did a clinical brain death determination on deep coma patients, and then divided them into brain death group and non-brain death group. According to the Chinese standards for determining brain death, both the groups accepted confirmatory tests including electroencephalograph (EEG), somatosensory evoked potentials (SEP), and transcranial Doppler (TCD). The sensitivity, specificity, false positive rate, and false negative rate were calculated to evaluate the accuracy of the confirmatory tests.

RESULTSAmong the 131 cases of patients, 103 patients met the clinical criteria of brain death. Respiratory arrest provocation test was performed on 44 cases and 32 cases (73%) successfully completed and confirmed that they have no spontaneous breathing. Of the three confirmation tests, EEG had the highest completion rate (98%) and good sensitivity (83%) and specificity (97%); TCD had followed completion rate (54%) and not good sensitivity (73%) and specificity (75%); SEP had the lowest completion rate (49%), good sensitivity (100%), and not good specificity (78%). After the combination of SEP or TCD with EEG, the specificity can increase to 100%.

CONCLUSIONSThe completion rate of respiratory arrest provocation test remains a problem in the clinical diagnosis of brain death. If the test cannot be completed, whether to increase a confirmatory test is debatable. SEP had an ideal sensitivity, and the specificity will reach 100% after combining with TCD or EEG. When a confirmed test was uncertain, we suggest increasing another confirmatory test.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Brain Death ; diagnosis ; physiopathology ; Evoked Potentials, Somatosensory ; physiology ; Female ; Humans ; Male ; Middle Aged ; Ultrasonography, Doppler, Transcranial ; Young Adult

PURPOSE: To evaluate whether intraoperative neurophysiologic monitoring (IONM) with combined muscle motor evoked potentials (mMEPs) and somatosensory evoked potentials is useful for more aggressive and safe resection in intramedullary spinal cord tumour (IMSCT) surgery. MATERIALS AND METHODS: We reviewed data from consecutive patients who underwent surgery for IMSCT between 1998 and April 2012. The patients were divided into two groups based on whether or not IONM was applied. In the monitored group, the procedures were performed under IONM using 75% muscle amplitude decline weaning criteria. The control group was comprised of patients who underwent IMSCT surgery without IONM. The primary outcome was the rate of gross total excision of the tumour on magnetic resonance imaging at one week after surgery. The secondary outcome was the neurologic outcome based on the McCormick Grade scale. RESULTS: The two groups had similar demographics. The total gross removal tended to increase when intraoperative neurophysiologic monitoring was used, but this tendency did not reach statistical significance (76% versus 58%; univariate analysis, p=0.049; multivariate regression model, p=0.119). The serial McCormick scale score was similar between the two groups (based on repeated measure ANOVA). CONCLUSION: Our study evaluated combined IONM of trans-cranial electrical (Tce)-mMEPs and SEPs for IMSCT. During IMSCT surgery, combined Tce-mMEPs and SEPs using 75% muscle amplitude weaning criteria did not result in significant improvement in the rate of gross total excision of the tumour or neurologic outcome.
Adult ; Evoked Potentials, Motor/physiology ; Evoked Potentials, Somatosensory/*physiology ; Female ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Spinal Cord Neoplasms/*surgery

The recent developments of new devices and advances in anesthesiology have greatly improved the utility and accuracy of intraoperative neurophysiological monitoring (IOM). Herein, we review the basic principles of the electrophysiological methods employed under IOM in the operating room. These include motor evoked potentials, somatosensory evoked potentials, electroencephalography, electromyography, brainstem auditory evoked potentials, and visual evoked potentials. Most of these techniques have certain limitations and their utility is still being debated. In this review, we also discuss the optimal stimulation/recording method for each of these modalities during individual surgeries as well as the diverse criteria for alarm signs.
Electroencephalography ; Electromyography ; Evoked Potentials, Motor/physiology ; Evoked Potentials, Somatosensory/physiology ; Humans ; Intraoperative Neurophysiological Monitoring ; Muscle, Skeletal/*physiology ; Spinal Cord/*physiology

PURPOSE: Subacute combined degeneration (SCD) involves progressive degeneration of the spinal cord, optic nerve, and peripheral nerves. Vitamin B12 (VB12) is a co-factor in myelin synthesis. Because each cell that constitutes the myelin component in the central nervous system and peripheral nervous system is different, it is improbable that these cells undergo simultaneous degeneration. However, the sequence of degeneration in SCD has not been established. MATERIALS AND METHODS: In this study, we analysed medical records and electrophysiological data of patients who showed neurological symptoms and whose serum VB12 levels were lower than 200 pg/mL. RESULTS: We enrolled 49 patients in this study. Their mean VB12 level was 68.3 pg/mL. Somatosensory evoked potential (SEP) study showed abnormal findings in 38 patients. Of the 40 patients who underwent visual evoked potential (VEP) study, 14 showed abnormal responses. Eighteen patients showed abnormal findings on a nerve conduction study (NCS). In this study, abnormal posterior tibial nerve SEPs only were seen in 16 patients, median nerve SEPs only were seen in 3 patients, abnormal VEPs only in two, and abnormal NCS responses in one patient. No patient complained of cognitive symptoms. CONCLUSION: In SCD, degeneration appears to progress in the following order: lower spinal cord, cervical spinal cord, peripheral nerve/optic nerve, and finally, the brain.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Evoked Potentials, Somatosensory/physiology ; Female ; Humans ; Male ; Middle Aged ; Subacute Combined Degeneration/*blood/metabolism/*physiopathology ; Vitamin B 12/blood ; Vitamin B 12 Deficiency/blood/complications ; Young Adult

Acute sensorimotor polyneuropathy that resembles Guillain-Barre syndrome (GBS) is rarely accompanied with nephrotic syndrome, and its underlying immunological mechanisms are unclear. A 56-year-old man presented with simultaneous acute progressive symmetric sensorimotor polyneuropathy and proteinuria. A kidney biopsy revealed focal segmental glomerulosclerosis. Serial electrophysiologic studies showed only a transient proximal conduction block in the median nerve, stimulated somatosensory evoked potential and prolonged terminal latencies of the median and peroneal nerves. The patient's neurologic deficits and kidney dysfunction recovered with corticosteroid treatment. Our case showed that somatosensory evoked potential study can be an important objective tool in the diagnosis of acute polyneuropathy with normal distal nerve conduction and that corticosteroids should be considered in the initial treatment of GBS-resembling polyneuropathy associated with nephrotic syndrome.
Evoked Potentials, Somatosensory/physiology ; Humans ; Male ; Middle Aged ; Nephrotic Syndrome/*diagnosis/*physiopathology ; Polyneuropathies/*diagnosis/*physiopathology

BACKGROUNDParoxysmal kinesigenic dyskinesia (PKD) is characterized by recurrent brief episodes of chorea and dystonia induced by sudden movement. Whether the central nervous system is hyper- or hypoexcitable in PKD remains undetermined. The aim of our study was to compare the somatosensory evoked potential (SEP) recovery cycle, a marker of somatosensory system excitability, in PKD patients and controls.

METHODSTwenty-four PKD patients (mean age of (20.0±5.3) years; 21 males, 3 females) and 18 control age-matched subjects (mean age of (22.0±5.0) years; 17 males, 1 female) were studied. The stimuli were delivered to the median nerve in the affected dominant arm in patients and in the dominant arm in controls. The change in SEP amplitude was measured after paired electrical stimulation at interstimulus intervals (ISIs) of 5, 20, and 40 ms. The SEPs evoked by S2 (test stimulus) were calculated by subtracting the response to S1 (the conditioning stimulus) from the response to a pair of stimuli (S1+S2), and their amplitudes were compared with those of the control response (S1) at each ISI. Analysis of variance (ANOVA) or equivalent was used for non-parametric data.

RESULTSIn patients, the P27 amplitude after the single stimulus (S1) was significantly larger than that after the control stimulus. The (S2/S1)×100 ratio for P14 and N30 SEPs did not differ significantly between PKD patients and normal subjects at ISI of 5 ms but were significantly higher in patients at ISIs of 20 and 40 ms (P<0.05).

CONCLUSIONSSomatosensory system disinhibition takes place in PKD. The finding of reduced suppression of different SEPs, each thought to have a different origin, suggests an abnormality of intracortical and subcortical inhibitory circuits.

Adolescent ; Adult ; Case-Control Studies ; Dystonia ; physiopathology ; Evoked Potentials, Somatosensory ; physiology ; Female ; Humans ; Male ; Young Adult

OBJECTIVETo investigate the value of somatosensory evoked potential (SEP) in the diagnosis of congenital scoliosis (CS) with intraspinal malformation.

METHODSFrom September 2001 to September 2007 posterior tibial nerve SEP were performed on 187 operatively treated CS patients. There were 85 male and 102 female, and the average age was 13.8 years (range from 30 to 22 years). Patients with intraspinal malformations were diagnosed by MRI. Absence of SEP waveforms, prolongation of peek latency or asymmetrical peek latency were defined as pathological change. The incidence of pathological SEP and clinical characteristics were compared between patients with and without intraspinal malformations.

RESULTSOf 187 patients, intraspinal malformations were diagnosed in 32 patients (17.1%). The incidence of intraspinal malformations was higher in type III (30.8%) than in type I and II CS patients (P < 0.05). The mean Cobb angle of scoliosis in patients with intraspinal malformations was greater than without intraspinal malformations, but there was no difference in kyphosis between the two groups. The ratio of abnormal SEP in patients with intraspinal malformations was 75.0% (24/32), while it was 38.7% (60/155) in patients without intraspinal malformations, and it showed significant difference between the two groups (χ(2) = 4.70, P < 0.05).

CONCLUSIONSSEP is a reliable tool for assessment of spinal cord function in patients with congenital scoliosis. It could be helpful for the diagnosis of intraspinal malformations, and also might provide an important reference for assessment and treatment of intraspinal malformations in congenital scoliosis.

Adolescent ; Child ; Child, Preschool ; Evoked Potentials, Somatosensory ; physiology ; Female ; Humans ; Male ; Preoperative Care ; Scoliosis ; complications ; diagnosis ; physiopathology ; Spinal Cord ; abnormalities ; Young Adult

OBJECTIVETo assess the changes of somatosensory evoked potentials (SEPs) during spinal cord ischemia and reperfusion injury and the value of SEP monitoring in evaluating neurological functions in this setting.

METHODSSpinal cord ischemia-reperfusion injury was induced in 28 rabbits by clamping the infrarenal aorta for 45 min, and the SEPs were monitored before and at 5, 10, and 15 min after ischemia, and at 15, 30, and 60 min and 2, 24 and 48 h after reperfusion. The neurological function score (NFS) of the rabbits was evaluated at 6, 12, 24 and 48 h after reperfusion, and the pathological changes of the spinal cord were observed 48 h after reperfusion.

RESULTSSEPs P1-wave latency significantly increased 5 min after ischemia (P<0.01) and the wave amplitude decreased 8 min after ischemia (P<0.01). SEPs disappeared 10 min after ischemia and recovered 15 min after reperfusion, but the P1-wave latency still remained longer and P1-wave amplitude lower than the measurements before ischemia (P<0.01). P1-wave amplitude became normal 15 min after the reperfusion (P>0.05), and the P1-wave latency gradually recovered 30 min after reperfusion, but still significantly longer than the preischemic value (P<0.01). P1-wave amplitude decreased again at 24 and 48 h after reperfusion (P<0.01). The NFS gradually increased at 24 and 48 h after the reperfusion (P<0.01). The changes in P1-wave amplitude at 24 and 48 h after reperfusion showed an obvious correlation to NFS (r=-0.881 and -0.925, respectively, P<0.01). Hemorrhage, swelling, and degeneration and neutrophil infiltration occurred in the spinal cord tissue 48 h after the reperfusion.

CONCLUSIONThe changes of SEP P1-wave amplitude can better reflect the spinal cord function than the wave latency during spinal cord ischemia-reperfusion injury, and SEP monitoring provides reliable evidence for prognostic evaluation of the neurological function.

Animals ; Evoked Potentials, Somatosensory ; physiology ; Female ; Ischemia ; physiopathology ; Male ; Monitoring, Physiologic ; methods ; Rabbits ; Reperfusion Injury ; physiopathology ; Spinal Cord ; blood supply