The neurophysiological evaluation in 60 patients with Kennedy disease / 中华神经科杂志

Objective:To study the neurophysiological features of Kennedy disease (KD) and to figure out the function of the nervous system.Methods:Subjects were recruited from the outpatient and the ward of Peking University Third Hospital from November 2010 to November 2022. Sixty patients with KD (29 patients with KD alone, 31 KD cases with the complication of diabetes mellitus) and 60 patients with diabetic polyneuropathy (DPN) were included in this study. Electrophysiological tests were performed in all subjects, including electromyogram, nerve conduction study, somaosensory evoked potential (SEP), contact heat evoked potential (CHEP) and triple stimulation technique (TST). Student′s t-tests were conducted to compare differences intra or inter groups of nerve conduction velocity and action potential of nerve conduction study, latency and interphase of SEP, initial peak latency of CHEP and other parameters. Results:Compared with the normative value, the amplitude of the sensory nerve action potential (SNAP) declined by 30%-80% in KD patients [median nerve (0.7±0.4) μV, ulnar nerve (0.8±0.3) μV, sural nerve (1.8±0.1) μV], the amplitude of the median and ulnar nerves was lower than the sural nerves ( t=2.43, P=0.010; t=2.40, P=0.010). The conduction time of peripheral segments of SEP and CHEP was prolonged by 115%-130%, while that of the central segments was prolonged by 104%-115% in SEP. TST test/TST control declined by 40%-60% in 17 patients with KD. The amplitude of SNAP declined by 30%-50% in patients with DPN [median nerve (2.9±0.5) μV, ulnar nerve (2.6±0.6) μV, sural nerve (1.6±0.2) μV], the amplitude of the sural nerves was lower than the median and ulnar nerves ( t=2.52, P=0.006; t=2.47, P=0.007). The conduction time of peripheral segments of SEP and CHEP was prolonged by 75%-112%, while that of the central segments was normal in both SEP and CHEP in DPN patients. Compared with DPN patients, the upper limb SNAP amplitude was lower in KD patients with the complication of diabetes mellitus [median nerve (0.7±0.3) μV, t=3.18, P=0.001; ulnar nerve (0.8±0.4) μV, t=3.20, P=0.001]. Conclusions:Sensory nerve is involved in patients with KD, including the large fiber and the small one. The central segments was abnormal in the deep sensory pathway, and the pyramid tract may be involved besides the anterior horn cell.

Somatosensory evoked potentials in clinical practice: a review / Potenciais evocados somatossensitivos na prática clínica: uma revisão

Abstract The authors present a review of the current use of somatosensory evoked potentials (SSEPs) in neurological practice as a non-invasive neurophysiological technique. For this purpose we have reviewed articles published in English or Portuguese in the PubMed and LILACS databases. In this review, we address the role of SSEPs in neurological diseases that affect the central nervous system and the peripheral nervous system, especially in demyelinating diseases, for monitoring coma, trauma and the functioning of sensory pathways during surgical procedures. The latter, along with new areas of research, has become one of the most important applications of SSEPs.

Resumo Os autores apresentam uma revisão do uso atual do potencial evocado somatossensitivo (PESS) na prática neurológica como uma técnica neurofisiológica não invasiva. Revisamos artigos publicados em Inglês ou Português nas bases de dados PubMed e LILACS. Nesta revisão abordamos o papel do PESS nas doenças neurológicas que atingem o sistema nervoso central e o sistema nervoso periférico, especialmente, nas doenças desmielinizantes, no monitoramento do coma, do trauma e da função das vias sensitivas durante os procedimentos cirúrgicos, que se tornou uma de suas aplicações mais importantes, assim como novas áreas de pesquisa.

Initial absence of N20 waveforms from median nerve somatosensory evoked potentials in a patient with cardiac arrest and good outcomes

A 34-year-old male was brought to the hospital with a chest gunshot wound. Pulseless upon arrival, blood pressure was absent for 10 minutes. A thoracotomy resulted in return of spontaneous circulation. On hospital day 5, with brainstem reflexes present, he was unresponsive to call or pain, exhibited generalized hyperreflexia and bilateral Babinskys. Median nerve somatosensory evoked potentials (mSSEPs) and brainstem auditory evoked potentials were obtained. International Federation of Clinical Neurophysiology recommendations for mSSEPs and brainstem auditory evoked potentials were followed. Despite absence of the N20 responses from cortical mSSEPs no withdrawal from care was agreed upon. After awaking on day 7, mSSEPs were repeated and present. The patient survived and was discharged with minor deficits. Bilateral absence of N20 responses from mSSEPs performed beyond 48 hours after resuscitation from cardiac arrest is highly associated with bad neurological outcomes. However, variation due to hypothermia, noisy signals, medications, and brain hypo-perfusion must be taken into account.

Trigeminal somatosensory evoked potential test as an evaluation tool for infraorbital nerve damage

BACKGROUND: Neurosensory changes are frequently observed in the patients with mid-face fractures, and these symptoms are often caused by infraorbital nerve (ION) damage. Although ION damage is a relatively common phenomenon, there are no established and objective methods to evaluate it. The aim of this study was to test whether trigeminal somatosensory evoked potential (TSEP) could be used as a prognostic predictor of ION damage and TSEP testing was an objective method to evaluate ION injury. METHODS: In this prospective TSEP study, 48 patients with unilateral mid-face fracture (only unilateral blow out fracture and unilateral zygomaticomaxillary fracture were included) and potential ION damages were enrolled. Both sides of the face were examined with TSEP and the non-traumatized side of the face was used as control. We calculated the latency difference between the affected and the unaffected sides. RESULTS: Twenty-four patients recovered within 3 months, and 21 patients took more than 3 months to recover. The average latency difference between the affected side and unaffected side was 1.4 and 4.1 ms for the group that recovered within 3 months and the group that recovered after 3 months, respectively. CONCLUSION: Patients who suffered ION damage showed prolonged latency when examined using the TSEP test. TSEP is an effective tool for evaluation of nerve injury and predicting the recovery of patients with ION damage.

Clinical and electrophysiological value of sensory tricks in cervical dystonia / 中华神经科杂志

Objective To investigate demography of sensory tricks in cervical dystonia (CD),and to discuss the relationship between sensory tricks and the function of sensorimotor integration of cerebral cortex,meanwhile to explore potential worthiness using sensory tricks in the management of CD.Methods We recruited 75 patients (23 male,52 female,male female ratio:1:2.26;aged 19-72 years,mean (42.45 ± 13.09) years) admitted to the Dystonia Clinic Center of the First Affiliated Hospital of Dalian Medical University from March 2016 to April 2013.Standardized questionnaire on sensory tricks was used to investigate the sensory tricks first recognized in 75 patients retrospectively.Median nerve somatosensory evoked potential via multipoint recording was measured in 43 CD patients who manifested as simple rotation of neck.Bilateral amplitudes of P22/N30 derived from F (3,4) were compared.Results Frequency of sensory tricks in CD was 85.53％ (64/75) in our research.As disease progressed,the type of sensory tricks used by patients may transform from one to another or even disappear.No statistically significant differences were found in ages among patients using classic sensory tricks,forcible tricks and patients without sensory tricks,whereas the complexity of the disease showed increased tendency among the three groups.Bilateral P22/N30 amplitudes of patients with classic sensory tricks showed no significant differences.P22/N30 amplitudes contralateral to the head turn were significantly higher than ipsilateral in patients using forcible tricks ((3.16 ± 1.71) μV vs (2.47 ± 1.28) μV,t =2.243,P=0.038) and patients without sensory tricks ((3.62 ±1.58) μV vs (2.73 ±1.14) μV,t=2.893,P=0.023).Tsui scores among patients using classic sensory tricks (9.36 ± 3.52) and forcible tricks (12.67 ± 5.00) or patients without sensory tricks (15.18 ± 4.07) had statistically significant differences (classic sensory tricks vs forcible tricks,t =-3.020,P =0.004;classic sensory tricks vs patients without sensory tricks,t =-4.452,P =0.000).Conclusions Types of sensory tricks used by patients are associated with severity of the disease.Different types of sensory tricks may reflect status of adaptive compensatory mechanism of the cerebral cortex.

Efficacy of regional cerebral oxygen saturation combined with neuroelectrophysiological monitoring in guiding intraoperative blood pressure management in elderly patients undergoing carotid endar-terectomy / 中华麻醉学杂志

Objective To evaluate the efficacy of regional cerebral oxygen saturation(rSO2) combined with neuroelectrophysiological monitoring in guiding intraoperative blood pressure management in elderly patients undergoing carotid endarterectomy. Methods Thirty patients of both sexes, aged 65-80 yr, of American Society of Anesthesiologists physical statusⅡorⅢ, scheduled for elective carotid endar-terectomy, were divided into 2 groups(n=15 each)using a random number table: control group(group C)and rSO2combined with neuroelectrophysiological monitoring group(group M). During occlusion of carotid artery, the vasoactive drugs were used to make systolic blood pressure(SBP)increase by 20%-30% of the baseline value in group C and to make rSO2not less than 20% of the baseline value, the ampli-tude of somatosensory evoked potential P40 not less than 50% of the baseline value and the amplitude of e-lectroencephalogram voltage not less than 50% in group M. SBP and rSO2were recorded immediately after intubation(T1), at 5 min after anesthesia induction(T2), at 5 min after blocking the carotid artery (T3), at 5 min after opening the carotid artery(T4)and immediately after extubation(T5). Decrease in rSO2≥20% of the baseline value was recorded. The carotid artery occlusion time, myocardial oxygen con-sumption and consumption of vasoactive drugs during occlusion were recorded. Results Compared with group C, SBP was significantly decreased at T3, and the consumption of vasoactive drugs and myocardial oxygen consumption were reduced in group M(P<0.05), and no significant change was found in rSO2at each time point in group M(P>0.05). Decrease in rSO2≥20% of the baseline value was not found in two groups. Conclusion rSO2combined with neuroelectrophysiological monitoring provides guidance for intra-operative blood pressure management in patients undergoing carotid endarterectomy.

Application of intraoperative neurophysiological monitoring in cervical intraspinal tumor surgery / 中华骨科杂志

Objective To investigate the efficiency of intraoperative neurophysiological monitoring in cervical spinal tumor surgery.Methods Retrospective case-control study comparing 23 cervical spinal tumor patients received surgery under neurophysiological monitoring (case) and 23 cases without neurophysiological monitoring (control).Results All of 46 cases,there were no significant differences of age,gender and preoperative neurological function.Duration of operation and estimated blood loss in the IONM cohort was less than the control group with significant difference.The preoperative JOA score of IONM group and control group were 12.0±2.4 and 12.7±2.1,with no significant difference.The postoperative JOA score of each group were 15.0±1.5 and 15.2±1.7,with no significant difference.The rate of cervical cord neurological improvement of IONM group was higher than control group,but there was no significant difference.In the IONM cohort,abnormal signal appeared in 8 cases,with 1 case developed new postoperative deficit,and the sensitivity and specificity of SEP were 100％ and 77.3％,the sensitivity and specificity of MEP were 100％ and 86.4％.Compared with preoperative SEP,4 cases showed major improvement (baseline increase ＞ 40％),2 cases showed moderate improvement (baseline increase:15％-40％).The coincidence rate of the SEP improvement and the AISA grade was 66.7％.Conclusion IONM could reduce the duration of operation and intraoperative blood loss.Changes of IONM were correlated with postoperative neurological function improvement.

The study and application of intraoperative neurophysiological monitoring in oblique lateral interbody fusion combined with posterior transpedicle internal fixation / 中华骨科杂志

Objective To investigate a reliable and practicable model of intraoperative neurophysiological monitoring (IONM) in oblique lateral interbody fusion (OLIF) combined with posterior transpedicle internal fixation.Methods A total of 34 consecutive patients who underwent OLIF combined with posterior transpedicle internal fixation with IONM at the SRRSH from November 2014 to July 2016 were collected and follow-up at least for 3 months postoperative.The intraoperative somatosensory evoked potentials (SEP),motor evoked potentials (MEP),dermatomal somatosensory evoked potential (DSEP) and spontaneous electromyography (sEMG) were used and evaluated,besides,triggered electromyography (tEMG) was used to monitor the implantation of pedicle screws,the possible reasons and treating procedures of monitoring alerts were summarized.Results A total of 34 cases of patients were effectively monitored during OLIF combined with posterior transpedicle internal fixation.SEP monitoring was successful in all patients,and no abnormal SEPs were observed in all cases.DSEP monitoring was successful in 20 cases (58.8％),and no abnormal DSEPs were observed in these patients.MEP was successfully monitored in all cases,eliminating the anesthesia factor,no abnormal MEPs were observed in all cases.The sensitivity and positive predictive value of SEP,MEP,DSEP were 0％.3 cases had abnormal sEMG reactions during the channel establishment which disappeared after adjustment of channel,and 2 cases which appeared abnormal wave recovered after brief observation.Among the 5 patients with abnormal wave,one case got numbness,one patient felt pain in front of the thigh postoperative.Among the other 29 patients without abnormal wave during channel establishment,one case appeared numbness.These 3 patients with neurologic symptoms recovered in 3 months after conservative treatment.The sensitivity and specificity of sEMG was 66.7％ and 90.3％ respectively,negative predictive value and positive predictive value were 96.6％ and 40％ respectively.6 screws got tEMG response after tapping even the intensity was less than 10mA,which showed broken codex of pedicle according to postoperative CT scan.Cornclusion Intraoperative application of sEMG monitoring in OLIF can obviously reduce the incidence of the neurological deficit,which was an effective method,tEMG monitoring during lumbar pedicle screw fixation can detect the mal-positioned screws and protect the nerve roots.SEP,MEP and DSEP did not seem well suited for OLIF.

Application of descending neurogenic evoked potentials monitoring during spinal deformity surgery / 中华骨科杂志

Objective To elevate the efficacy and safety of descending neurogenic evoked potentials (DNEP) monitoring during severe rigid spinal deformity surgery.Methods All of 108 patients (43 males,65 females) who underwent surgical treatment for spinal deformity in our spinal center from July 2010 to August 2013 were retrospectively reviewed.The average age (17.5±5.8) ys(range 12-50 ys),the average following period is 38.6 months(range 24-52 months).Combined monitoring of SEP,MEP and DNEP model were used during surgery.All subjects with no neurological deficits preoperatively and got satisfied outcomes.Respectively evaluate the results of neurophysiological intraoperative monitoring (IOM).Data were collected to elevate the efficacy and safety of DNEP monitoring.Results All of 108 patients,15 patients (13.9％,15/108) showed significant changes of neurophysiological parameters,of which 9 cases (60％,9/15) were identified as true positive and 6 cases (40％,6/15) were identified as false positive.During the following-up period,2 patients developed permanent neurological deficit,and 3 patients showed transient neurological deficit who got fully recovered within 6 months after operation.DNEP showed alert in all 5 patients with truepositive alarm,of which 2 patients developed permanent neurological dysfunction and 3 cases showed postoperative short nerve dysfunction that got fully recovery within 6 months after operation.The sensitivity and specificity of SEP+MEP and DNEP were 100％ and 97.98％,100％ and 98.99％,respectively.Conclusion Combining use of MEP+SEP+DNEP monitoring during surgical treatment of spinal deformities presented to be a highly reliable method for the detection and prevention of iatrogenic injury.The results confirmed a high efficacy and safety of DNEP monitoring during spinal surgery.

Predicting the prognosis for comatose patients: somatosensory evoked potentials combined with event-related potentials / 中华神经科杂志

Objective To explore the effectiveness of using somatosensory evoked potentials (SEPs) combined with event-related potentials (ERPs) to predict the prognosis of comatose patients in neurologic intensive care units (N-ICU).Methods A prospective cohort study was conducted in 53 comatose patients enrolled from the Department of Neurology,Xuanwu Hospital of Capital Medical University from January 2011 to June 2014.Short-latency somatosensory evoked potentials (SLSEP),middle-latency somatosensory evoked potentials (MLSEP),N100,and mismatch negative (MMN) were recorded in these comatose patients in N-ICU within one week after coma onset.All patients were evaluated with Glasgow Outcome Scale (GOS) in 3 months after onset.GOS grades 3 to 5 were considered the good outcome; while GOS grades 1 and 2 were considered poor.SLSEP,MLSEP,N100 and MMN were also recorded in 30 healthy controls.The consistency between SLSEP,MLSEP,N100,MMN,and prognosis,as well as the prognostic authenticity of SLSEP,MLSEP,N100 and MMN were analyzed.Results The amplitude was smaller and the latency became longer in comatose patients,compared with healthy controls.The latency of N20,N60,N100 and MMN in patients with good outcome was (21.73 ±2.91) ms,(68.67 ±7.60) ms,(114.81 ±21.60) ms and (194.10 ±55.31) ms,respectively.And the latency of N20,N60,N100 and MMN in patients with poor outcome was (20.74 ±2.05) ms,(64.20 ±5.29) ms,(109.74 ±21.30) ms and (181.00 ± 50.32) ms,respectively.The consistency between poor outcome and absence of evoked potentials for N20,N60,N100 and MMN was satisfactory (x2 =14.60,10.59,14.46,18.12 respectively,all P ＜ 0.05).When combined SEPs with ERPs,the sensitivity was 85.2％,specificity was 74.2％,and general correct rate was 86.8％,respectively,for good outcome; the sensitivity was 74.2％,specificity was 85.2％,and general correct rate was 86.8％,respectively,for poor outcome.Conclusions The bilateral absence of N20 has a good power for predicting the poor outcome in comatose patients,while the bilateral existence of N60,N100 and MMN has a good power for predicting the good outcome.The combined use of SEPs and ERPs in evaluating and predicting the outcomes in comatose patients is suggested.

Variations on nerve regeneration microenvironment and motor function of rat models of spinal cord injury under mild hypothermia / 中国组织工程研究

BACKGROUND:Clinical studies have demonstrated that systemic mild hypothermia could significantly reduce the disability and mortality rate of patients with severe traumatic brain injury. In recent years, the researches about the treatment of spinal cord injury by mild hypothermia have been successively carried out. OBJECTIVE:To investigate the effects of mild hypothermia on nerve regeneration microenvironment after spinal cord injury and explore the possible underlying mechanism of nerve regeneration and functional recovery after spinal cord injury in rats. METHODS:Twenty out of sixty-seven rats were randomly selected as the sham group, and other rats were used to establish spinal cord injury models in T9 segment using modified Alen's method. Three rats were excluded for failure in spinal cord injury induction and four rats for death during modeling. The rest 40 rats were randomly and evenly divided into the spinal cord injury and mild hypothermia groups (n=20 rats/group). The rats in the sham and spinal cord injury groups were placed in the operating table with normal temperature, making their rectal temperature at 37.0±0.5℃ for 72 hours. The rats in the mild hypothermia group were placed on ice blanket machine, making their rectal temperature at 34.0±0.5℃ for 72 hours, then the temperature was naturaly rewarmed. RESULTS AND CONCLUSION:Compared with spinal cord injury group, the apoptosis index and the level of aquaporin 4/9 mRNA and protein expression in spinal cord injury tissue were al decreased, somatosensory evoked potential latency and amplitude were recovered, and the motor functional scores were increased in the mild hypothermia group. These results indicate that mild hypothermia play its protective effect on spinal cord injury through attenuating apoptosis of neural cels and decreasing aquaporin 4/9 mRNA and protein expression levels.

Potencial evocado somatossensitivo transoperatório na malformação de Chiari: relato de caso e argumentação / Somatosensory evoked potential intraoperatively in malformation Chiari. Case report and discussion

Os autores relatam o caso uma mulher de 23 anos, sintomática pela malformação de Chiari, submetida à descompressão cirúrgica da fossa posterior do crânio, com o transoperatório monitorizado por meio de potencial evocado somatossensitivo que auxiliou no resultado satisfatório obtido. É sugerido que as cirurgias para tratamento da malformação de Chiari sejam sempre monitorizadas por esse método.

The authors report the case of a woman 23 years, symptomatic for Chiari malformation, that underwent surgical decompression of the cranium posterior fossa, with intraoperative monitored by evoked potential somatosensitivo, who assisted in the satisfactory outcome. It is suggested that the surgical treatment of Chiari malformation are always monitored by this method.

Impact of mild hypothermia on changes of somatosensory evoked potential and synaptophysin mRNA level following traumatic brain injury / 中华创伤杂志

Objective To investigate effect of mild hypothermia on changes of somatosensory evoked potential (SEP) and synaptophysin mRNA level after traumatic brain injury (TBI) and determine hypothermia-induced neuroprotection.Methods Forty-five SD rats were allocated into mild hypothermia group,TBI group and sham operation group with 15 rats per group according to the random number table.Left-side fluid percussion impact was performed to induce models of TBI.Rats were exposed to hypothermia environment (32-35℃) for 6 hours in mild hypothermia group after TBI.Rats in sham operation group were treated by only drilling on left side of the head,rather than hitting.To evaluate function outcome,modified neurological severity score (mNSS),SEP and synaptophysin mRNA level were measured at 6 hours,24 hours and 7 days postinjury.Results The mNSS in mild hypothermia group lowered compared with TBI group,especially at 24 hours and 7 days (P ＜ 0.05).SEP in mild hypothermia group was significantly shortened at 6 and 24 hours compared with TBI group (P ＜ 0.05),but SEP revealed no significant difference among the 3 groups at 7 days (P ＞ 0.05).Level of synaptophysin mRNA in mild hypothermia group increased at 6 hours postinjury compared with TBI group [(0.08 ± 0.02) vs (0.12 ±0.04)],with further increase at 7 days postinjury[(0.06 ± 0.01) vs (0.33 ± 0.10)] (P ＜0.05).Conclusion The shortage of nerve conduction time of the injured side and promotion of nerve regeneration suggest the neuroprotective role of mild hypothermia following TBI.

Animal models of spinal cord injury：application and research progress of evoked potentials / 中国组织工程研究

BACKGROUND:With the development of industrial society and traffic, the incidence of spinal cord injury has gradualy increased. In addition to radiological laboratory examinations, the neurophysiological test also becomes an effective way of auxiliary examination. Due to the high accuracy and easy operating, neurophysiological test is widely used and the evoked potentials play a role in this project. OBJECTIVE:To summarize the application of somatosensory evoked potentials and motor evoked potentials in rabbits of spinal cord injury. METHODS:A computer-based online research of CNKI and PubMed databases was performed with the key words of “spinal cord injury; evoked potentials; animal models” in Chinese and English. Finaly 33 articles were included in the analysis according to the inclusion and exclusion criteria. RESULTS AND CONCLUSION:The operational approach, waveform analysis, application value, influencing factor of somatosensory evoked potentials and motor evoked potentials were determined in details, the correlation between evoked potentials and prognosis assessment in animals was also detected. Somatosensory evoked potentials is a good indicator for the evaluation of dorsal funiculus of spinal cord, it is easy to operate and reflects the changes of sensory functions. Motor evoked potentials can provide sensitive diagnosis of spinal cord diseases, and they wil be used as a means to assess the spinal cord injury during rehabilitation. The combination of the two can provide a more accurate result.

Mouse nerve growth factor injection via different ways for treatment of peripheral nerve injury / 中国组织工程研究

BACKGROUND:Mouse nerve growth factor can promote the repair and regeneration of injured nerves, but current experimental research shows that the effects of different treatment methods are stil controversial. OBJECTIVE:To evaluate the effect of mouse nerve growth factor injection via different ways on the treatment of peripheral nerve injury. METHODS:Total y 52 patients with peripheral nerve injury were randomly assigned into two groups:experimental group (local injection of mouse nerve growth factor, n=27) and control group (systemic administration of mouse nerve growth factor, n=25). The treatment was performed once a day, and lasted for 4 weeks. Then, the clinical efficacy and recovery of neurological function were compared. RESULTS AND CONCLUSION:The good and effective rates were 85%(n=23) and 93%(n=25) in the experimental group, while 72%(n=18) and 84%(n=21) in the control group, respectively, which were significantly better in the experimental group than the control group (P<0.05). In the experimental group, 13 cases developed transient pain at injection site, including one case of remission undergoing oral analgesics;in the control group, 12 cases had transient pain at injection site, without any treatment. The results suggest that both local and total body injection of mouse nerve growth factor are safe and effective for treatment of peripheral nerve injury, but local injection is superior to systemic administration.

Changes of somatosensory evoked potentials and quantitative electroencephalogram in response to mild hypothermia following traumatic brain injury in rats / 中华创伤杂志

Objective To investigate the effect of mild hypothermia on neuroprotection and prognosis prediction of rats with traumatic brain injury (TBI) by dynamically monitoring the somatosensory evoked potentials (SEP) and quantitative electroencephalogram (QEEG).Methods Forty healthy adult male SD rats were randomly divided into four groups according to random number table,ie,normal control group (with no intervention),sham operation group (fenestration only,without drilling),TBI group (fluid percussion was used to produce moderate to severe TBI),and mild hypothemia group (ice blanket was used immediately after TBI for continuous physical cooling and rectal temperature was maintained at 32-35℃ and rewarmed to 37℃ 6 hours after the initiation of cooling),with 10 rats per group.Changes of SEP and QEEG in all groups were monitored at 6,24 hours,and 7 days after TBI.Results (1) Compared with TBI group,the latency of SEP waves (P1 and N1) on the injured side in mild hypothemia group began to shorten at 24 hours(P ＜ 0.05) and were close to that in the sham operation group at 7 days.(2) Except for normal control group and sham operation group,QEEG in TBI group showed decrease of α rhythm,increase of reactivity slow waves,and decrease or disappearance of QEEG relative power spectral values at all time points.In mild hypothermia group,the reactivity slow waves were decreased with a small amount of α wave; QEEG relative power spectral values were increased at 24 hours and 7 days (especially at 24 hours),but werc still lower than those in normal control group (P ＜ 0.05).Conclusion Mild hypothermia exerts neuroprotective effect through reducing SEP latency,raising relative power spectral values of QEEG,and improving the nerve conduction and brain electrical activity of the injured side.

Effect of ketamine on sensory processing of thalamocortical circuits in rats / 中华麻醉学杂志

Objective To investigate the effect of ketamine injected into the ventral posteromedial nucleus (VPM) of the thalamus on sensory processing of thalamocortical circuits in rats.Methods Twenty-four SpragueDawley rats in which the neurophysiological model was successfully established,aged 2 months,weighing 280-350g,were randomly divided into 4 groups (n=6 each):control group (group C),specific inhibitor of NMDA receptors AP-5 group (group A) and two different concentrations of ketamine groups (K1 and K2 groups).Normal saline 1 μl,AP-5 5 μg/μl and ketamine 12.5 and 25.0 μg/μl were injected into the VPM in A,AP-5,K1 and K2groups,respectively.Somatosensory-evoked potentials (SEPs) in the primary somatosensory cortex (S1) of the rat was recoded at 4 time periods:300 s before administration-immediately after administration (baseline,T0),immediately after administration-300 s after administration (T1),300-600 s after administration (T2),600-900 s after administration (T3).Results Compared with the baseline value at T0,there was no significant difference in the peak amplitude of SEPs at T1-3 in group C (P ＞ 0.05),and the peak amplitude of SEPs was significantly decreased at T1-3 in A,K1 and K2 groups (P ＜ 0.05).Compared with group C,the peak amplitude of SEPs was significantly decreased at T1-3 in A,K1 and K2 groups (P ＜ 0.05).Compared with group A,the peak amplitude of SEPs was significantly increased at T3 in group K1 (P ＜ 0.05).There was no significant difference in the peak amplitude of SEPs between A and K2 groups,K1 and K2 groups (P ＞ 0.05).Conclusion Ketamine results in damage to the integrity of sensory processing of thalamocortical circuits and reduction of incoming sensory information,and the mechanism may be related to blockade of NMDA receptors in VPM of the thalamus.

The roles of the contact heat evoked potential in evaluating the small nerve fibers of cranial and spinal in elderly diabetic patients / 中华老年医学杂志

Objective To study the roles of the contact heat evoked potential (CHEP) in evaluating the small nerve fibers of cranial and spinal in elderly diabetic patients,and to analyze the feature of the small fibers in order to provide scientific foundations for early diagnosis of diabetic neuropathy (DN).Methods Totally 50 diabetic patients and 40 healthy subjects were included in this study.The diabetic patients were divided into the normal nerve conduction group (n=17) and the abnormal nerve conduction group (n=33).CHEP was determined and thermal stimuli was given to the area of eyelid,forearm and peroneal.Sensory and motor nerve conduction velocity in the upper and lower limbs were tested in all diabetic patients.Results Compared with the healthy group,the N wave latencies were prolonged and the N-P amplitudes were reduced in the area of eyelid,forearm and peroneal in diabetic patients (all P＜0.01).Compared with the healthy group,the logarithm of N-P amplitudes were reduced in areas of forearm and peroneal [(1.70±0.10) vs.(1.60±0.14),(1.65±0.078) vs.(1.54±0.15),both P＜0.05] and N wave latencies were prolonged in eyelid area [(343.1±18.2) ms vs.(385.4±26.5) ms,P＜0.05] in normal nerve conduction group.Compared to group with normal nerve conduction velocity,the logarithm of N-P amplitudes was reduced in peroneal area [(1.54±0.15) vs.(1.44±0.15),P＜0.05] in abnormal nerve conduction group.Conclusions CHEP can detect the early impairment of the small fibers in elderly diabetic patients.The early smallfiber impairments in diabetic neuropathy may be axon-oriented in spinal nerves and myelin-oriented in cranial nerves.

The study of somatosensory evoked potential of the upper limbs in subacute combined degeneration / 中华神经科杂志

Objective To analyze the features of the latency and interval in somatosensory evoked potentials (SEP) of the upper limbs in subacute combined degeneration(SCD),and evaluate the SEP of the upper limbs in the diagnosis of SCD.Methods Thirty-four defined SCD patients and 22 healthy controls were included in this study.The patients underwent the SEP test and the magnetic resonance imaging(MRI)of spinal cord.The SEP results of the patients were compared with those of the controls.The results of the SEP,which were divided into the peripheral part and central part to be evaluated,were also compared with the related results of the SEP and MRI.Results Compared with the controls,the N9 ((10.80 ± 1.07) ms vs (10.23 ± 0.64) ms,t =3.223),P14 ((17.28 ± 2.56) ms vs (14.62 ± 0.84) ms,t =6.643),N9-P14 ((6.48±2.27) ms vs(4.40-0.58) ms,t =5.951) in the upper limbs and N9((12.11 ±0.83) ms vs (10.93±0.56) ms,t=5.690),P30((36.96±5.56) ms vs(30.37±2.20) ms,t=7.217),P38 ((46.94 ±5.83) ms vs(39.80 ±2.54) ms,t =7.353) in the lower limbs of SCD patients were prolonged (all P ＜0.01),however,the P14-N20 was prolonged without statistical significance.The abnormality of SEP was 80.9％ (110/136),in which the abnormality of the upper limbs was 85.3％ (58/68)while that of the lower limbs was 76.5％ (52/68).N9-P14 had the highest abnormality rate which was 72.1％ (49/68).The patients with SCD with normal N9 had prolonged N9-P14 ((5.98 ± 1.90) ms vs(4.40 ± 0.58) ms,t =5.267,P ＜ 0.01).Conclusions Subacute combined degeneration can involve not only the peripheral part of the somatosensory pathway but also the central part including the brainstem and brain.In the SEP of upper limbs,N9-P14 has the highest abnormality rate which suggests that the part from cervical spinal cord to the brainstem may be the most vulnerable in SCD.The test of SEP in the upper limbs may provide evidence for the damage in the central part in SCD.

Comparison of accuracy of jugular venous oxygen saturation, somatosensory evoked potentials and motor evoked potentials in estimation of occurrence of intraoperative cerebral ischemia in patients undergoing clipping of intracranial aneurysm / 中华麻醉学杂志

Objective To compare the accuracy of jugular venous oxygen saturation (SjvO2),somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) in estimation of the occurrence of intraoperative cerebral ischemia in patients undergoing clipping of intracranial aneurysm.Methods Forty-three ASA Ⅰ or Ⅱ patients of both sexes,aged 18-64 yr,with a body mass index of 20-25 kg/m2,undergoing clipping of intracranial aneurysm,were studied.Anesthesia was induced with sufentanil,rocuronium and propofol.The patients were tracheal intubated and mechanically ventilated.Anesthesia was maintained with remifentanil and propofol.Blood samples were taken from the jugular bulb for detection of SjvO2 before aneurysm clipping or temporary occlusion of parent artery and at 1,3,10,20 and 30 min after clipping aneurysm or temporary occlusion of parent artery.The amplitude and latency of SSEPs and MEPs were recorded simultaneously.The occurrence of cerebral ischemia estimated by SjvO2,SSEPs and MEPs was recorded.The condition of nerve defect was recorded within 3 days after operation and the gold standard of cerebral ischemia was defined as the occurrence of nerve defect.Results Among 43 patients,14 cases were diagnosed as having brain ischemia.The sensitivity and specificity of SjvO2 in estimation of the occurrence of intraoperative brain ischemia were 71％ and 93％,respectively (P ＜ 0.01).The sensitivity and specificity of SSEPs in estimation of the occurrence of intraoperative brain ischemia were 71％ and 62％,respectively (P ＜ 0.05).When the diagnostic criterion of cerebral ischemia was defincd as a decrease in the amplitude of MEPs or prolongation of the latency MEPs,the sensitivity and specificity of MEPs in estimation of the occurrence of intraoperative brain ischemia were 79 ％ and 52 ％,respectively (P ＞ 0.05).When the diagnostic criterion of cerebral ischemia was defined as a loss of the amplitude of MEPs,the sensitivity and specificity of MEPs in estimation of the occurrence of intraoperative brain ischemia were 57％ and 93％,respectively (P ＜0.05).Conclusion The sensitivity of SjvO2 and SSEPs in estimation of the occurrence of intraoperative brain ischemia is higher,however,the specificity of SjvO2 and MEPs is higher,indicating that SjvO2 is a reliable criteria for estimation of the occurrence of intraoperative brain ischemia in patients undergoing clipping of intracranial aneurysm.