RESUMEN
ABSTRACT In 1951, the physiologist George Duncan Dawson presented his work with the averaging of the signal in the evoked potentials (EPs), opening a new stage in the development of clinical neurophysiology. The authors present aspects of Professor Dawson's biography and a review of his work on the EPs and, mainly, the article reveals the new technique in detail that would allow the growth of the clinical application of the visual, auditory, and somatosensory EPs.
RESUMO Em 1951 o fisiologista George Duncan Dawson apresentou seu trabalho com a promediação de sinal nos potenciais evocados, abrindo uma nova etapa no desenvolvimento da neurofisiologia clínica. Os autores apresentam aspectos da biografia do professor Dawson e uma revisão de seus trabalhos sobre os potenciais evocados, principalmente do artigo que mostrava a nova técnica, que viria a permitir o crescimento da aplicação clínica dos potenciais evocados visual, auditivo e somatossensitivo.
Asunto(s)
Humanos , Historia del Siglo XX , Invenciones , Neurofisiología/métodos , Potenciales Evocados , Potenciales Evocados Somatosensoriales , Potenciales Evocados VisualesRESUMEN
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.
Asunto(s)
Humanos , Potenciales Evocados Motores , Potenciales Evocados SomatosensorialesRESUMEN
BACKGROUND AND PURPOSE: We aimed to determine the effectiveness of intraoperative neurophysiological monitoring focused on the transcranial motor-evoked potential (MEP) in patients with medically refractory temporal lobe epilepsy (TLE). METHODS: We compared postoperative neurological deficits in patients who underwent TLE surgery with or without transcranial MEPs combined with somatosensory evoked potential (SSEP) monitoring between January 1995 and June 2018. Transcranial motor stimulation was performed using subdermal electrodes, and MEP responses were recorded in the four extremity muscles. A decrease of more than 50% in the MEP or the SSEP amplitudes compared with baseline was used as a warning criterion. RESULTS: In the TLE surgery group without MEP monitoring, postoperative permanent motor deficits newly developed in 7 of 613 patients. In contrast, no permanent motor deficit occurred in 279 patients who received transcranial MEP and SSEP monitoring. Ten patients who exhibited decreases of more than 50% in the MEP amplitude recovered completely, although two cases showed transient motor deficits that recovered within 3 months postoperatively. CONCLUSIONS: Intraoperative transcranial MEP monitoring during TLE surgery allowed the prompt detection and appropriate correction of injuries to the motor nervous system or ischemic stroke. Intraoperative transcranial MEP monitoring is a reliable modality for minimizing motor deficits in TLE surgery.
Asunto(s)
Humanos , Electrodos , Epilepsia del Lóbulo Temporal , Potenciales Evocados Somatosensoriales , Extremidades , Monitorización Neurofisiológica Intraoperatoria , Monitoreo Intraoperatorio , Músculos , Sistema Nervioso , Accidente Cerebrovascular , Lóbulo TemporalRESUMEN
We report two cases of subacute combined degeneration (SCD) caused by nitrous oxide (N₂O) gas intoxication, which is rarely reported in Korea. Two patients recreationally inhaled N₂O gas daily for several months. They presented with paresthesia of limbs, voiding difficulty, and gait disturbance. The initial vitamin B₁₂ levels were normal or decreased, but homocysteine levels of the two patients were increased. Magnetic resonance imaging of the cervical spine showed T2-weighted hyperintensity in the bilateral dorsal columns of the cervical spinal cord. Electromyography and somatosensory evoked potential tests for both patients suggested posterior column lesion of the spinal cord combined with sensorimotor polyneuropathy. According to these findings, we concluded that the two patients had SCD. The patient’s symptoms partially improved after cessation of N₂O gas inhalation and the receiving of vitamin B₁₂ supplementation therapy. As the incidence of recreational N₂O gas inhalation is increasing in Korea, physicians must be alert to the N₂O induced SCD in patients presenting with progressive myelopathy.
Asunto(s)
Humanos , Médula Cervical , Electromiografía , Potenciales Evocados Somatosensoriales , Extremidades , Marcha , Homocisteína , Incidencia , Inhalación , Corea (Geográfico) , Imagen por Resonancia Magnética , Óxido Nitroso , Parestesia , Polineuropatías , Recreación , Médula Espinal , Enfermedades de la Médula Espinal , Columna Vertebral , Degeneración Combinada Subaguda , Vitamina B 12 , VitaminasRESUMEN
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.
Asunto(s)
Humanos , Potenciales Evocados Somatosensoriales , Métodos , Fracturas Orbitales , Estudios Prospectivos , Traumatismos del Nervio TrigéminoRESUMEN
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.
Asunto(s)
Adulto , Humanos , Masculino , Presión Sanguínea , Encéfalo , Tronco Encefálico , Resultados de Cuidados Críticos , Potenciales Evocados Auditivos del Tronco Encefálico , Potenciales Evocados Somatosensoriales , Paro Cardíaco , Hipotermia , Nervio Mediano , Enfermedades del Sistema Nervioso , Neurofisiología , Pronóstico , Reflejo , Reflejo Anormal , Resucitación , Toracotomía , Tórax , Heridas por Arma de FuegoRESUMEN
Intraoperative monitoring (IOM) utilizes electrophysiological techniques as a surrogate test and evaluation of nervous function while a patient is under general anesthesia. They are increasingly used for procedures, both surgical and endovascular, to avoid injury during an operation, examine neurological tissue to guide the surgery, or to test electrophysiological function to allow for more complete resection or corrections. The application of IOM during pediatric brain tumor resections encompasses a unique set of technical issues. First, obtaining stable and reliable responses in children of different ages requires detailed understanding of normal ageadjusted brain-spine development. Neurophysiology, anatomy, and anthropometry of children are different from those of adults. Second, monitoring of the brain may include risk to eloquent functions and cranial nerve functions that are difficult with the usual neurophysiological techniques. Third, interpretation of signal change requires unique sets of normative values specific for children of that age. Fourth, tumor resection involves multiple considerations including defining tumor type, size, location, pathophysiology that might require maximal removal of lesion or minimal intervention. IOM techniques can be divided into monitoring and mapping. Mapping involves identification of specific neural structures to avoid or minimize injury. Monitoring is continuous acquisition of neural signals to determine the integrity of the full longitudinal path of the neural system of interest. Motor evoked potentials and somatosensory evoked potentials are representative methodologies for monitoring. Free-running electromyography is also used to monitor irritation or damage to the motor nerves in the lower motor neuron level : cranial nerves, roots, and peripheral nerves. For the surgery of infratentorial tumors, in addition to free-running electromyography of the bulbar muscles, brainstem auditory evoked potentials or corticobulbar motor evoked potentials could be combined to prevent injury of the cranial nerves or nucleus. IOM for cerebral tumors can adopt direct cortical stimulation or direct subcortical stimulation to map the corticospinal pathways in the vicinity of lesion. IOM is a diagnostic as well as interventional tool for neurosurgery. To prove clinical evidence of it is not simple. Randomized controlled prospective studies may not be possible due to ethical reasons. However, prospective longitudinal studies confirming prognostic value of IOM are available. Furthermore, oncological outcome has also been shown to be superior in some brain tumors, with IOM. New methodologies of IOM are being developed and clinically applied. This review establishes a composite view of techniques used today, noting differences between adult and pediatric monitoring.
Asunto(s)
Adulto , Niño , Humanos , Anestesia General , Antropometría , Neoplasias Encefálicas , Encéfalo , Nervios Craneales , Electromiografía , Potenciales Evocados Auditivos del Tronco Encefálico , Potenciales Evocados Motores , Potenciales Evocados Somatosensoriales , Neoplasias Infratentoriales , Monitorización Neurofisiológica Intraoperatoria , Estudios Longitudinales , Monitoreo Intraoperatorio , Neuronas Motoras , Músculos , Neurofisiología , Neurocirugia , Nervios Periféricos , Estudios ProspectivosRESUMEN
Intraoperative monitoring (IOM) utilizes electrophysiological techniques as a surrogate test and evaluation of nervous function while a patient is under general anesthesia. They are increasingly used for procedures, both surgical and endovascular, to avoid injury during an operation, examine neurological tissue to guide the surgery, or to test electrophysiological function to allow for more complete resection or corrections. The application of IOM during pediatric brain tumor resections encompasses a unique set of technical issues. First, obtaining stable and reliable responses in children of different ages requires detailed understanding of normal ageadjusted brain-spine development. Neurophysiology, anatomy, and anthropometry of children are different from those of adults. Second, monitoring of the brain may include risk to eloquent functions and cranial nerve functions that are difficult with the usual neurophysiological techniques. Third, interpretation of signal change requires unique sets of normative values specific for children of that age. Fourth, tumor resection involves multiple considerations including defining tumor type, size, location, pathophysiology that might require maximal removal of lesion or minimal intervention. IOM techniques can be divided into monitoring and mapping. Mapping involves identification of specific neural structures to avoid or minimize injury. Monitoring is continuous acquisition of neural signals to determine the integrity of the full longitudinal path of the neural system of interest. Motor evoked potentials and somatosensory evoked potentials are representative methodologies for monitoring. Free-running electromyography is also used to monitor irritation or damage to the motor nerves in the lower motor neuron level : cranial nerves, roots, and peripheral nerves. For the surgery of infratentorial tumors, in addition to free-running electromyography of the bulbar muscles, brainstem auditory evoked potentials or corticobulbar motor evoked potentials could be combined to prevent injury of the cranial nerves or nucleus. IOM for cerebral tumors can adopt direct cortical stimulation or direct subcortical stimulation to map the corticospinal pathways in the vicinity of lesion. IOM is a diagnostic as well as interventional tool for neurosurgery. To prove clinical evidence of it is not simple. Randomized controlled prospective studies may not be possible due to ethical reasons. However, prospective longitudinal studies confirming prognostic value of IOM are available. Furthermore, oncological outcome has also been shown to be superior in some brain tumors, with IOM. New methodologies of IOM are being developed and clinically applied. This review establishes a composite view of techniques used today, noting differences between adult and pediatric monitoring.
Asunto(s)
Adulto , Niño , Humanos , Anestesia General , Antropometría , Neoplasias Encefálicas , Encéfalo , Nervios Craneales , Electromiografía , Potenciales Evocados Auditivos del Tronco Encefálico , Potenciales Evocados Motores , Potenciales Evocados Somatosensoriales , Neoplasias Infratentoriales , Monitorización Neurofisiológica Intraoperatoria , Estudios Longitudinales , Monitoreo Intraoperatorio , Neuronas Motoras , Músculos , Neurofisiología , Neurocirugia , Nervios Periféricos , Estudios ProspectivosRESUMEN
Background@#Brain death is the irreversible cessation of the function of the brain including the brainstem. In 2013, the Brain Injury Evaluation Quality Control Centre (BQCC) of the National Health and Family Planning Commission issued criteria and practical guidelines for the determination of brain death. This study aimed to evaluate whether the institutions have adopted these guidelines and to make suggestions for the improvement of the current criteria and practical guidelines for brain death determination in China.@*Methods@#Consecutive brain death cases from 44 hospitals were evaluated for summary statistics for the following data: the performance of BQCC criteria and practical guidelines, clinical examination, apnea testing, ancillary testing, and the number of examinations as well as the waiting periods between examinations and details of who determined brain death. Data analysis was conducted from January 2013 to December 2017.@*Results@#A total of 550 cases were obtained. All patients were determined to have deep coma and met the prerequisites for clinical testing. The performance rates of four brainstem reflex examinations (except cough reflex) ranged from 97.5% to 98.0%, and the completion rate as well as the coincidence rate were both 100.0%. The 238 cases (50.7%) completed apnea testing, and 231 cases (42.0%) had to stop apnea testing during the examination because of instability. The performance rates of the three ancillary tests, including electroencephalogram, short-latency somatosensory evoked potential, and transcranial Doppler, were 89.5%, 67.5%, and 79.5%, respectively; furthermore, the coincidence rates were 98.6%, 96.5%, and 99.5%, respectively. The combination of two ancillary tests was more accurate than one single ancillary test. A total of 401 (72.9%) cases successfully underwent two separate examinations to determine brain death with at least a 12-h waiting period. All brain death cases were determined by at least two qualified physicians.@*Conclusion@#This study might provide suggestions for brain death determination in China.
Asunto(s)
Humanos , Muerte Encefálica , Diagnóstico , Electroencefalografía , Potenciales Evocados Somatosensoriales , Ultrasonografía Doppler TranscranealRESUMEN
Herpes zoster is characterized by vesicular eruption and rash of the skin in the affected dermatomes. Sensory symptoms such as pain and hypesthesia are often accompanied in patients with herpes zoster. While motor paralysis is uncommon, abdominal paralysis can result in rare complications such as abdominal wall pseudohernia. In the present report, we discuss the case of a 62 year-old man who presented with abdominal wall protrusion after herpes zoster infection involving the right T10-T12 dermatomes. Magnetic resonance imaging findings were not specifically correlated with abdominal wall protrusion. Needle electromyography revealed abnormal spontaneous activity in the right paraspinal muscles at the T10-T12 levels, rectus abdominis, and external oblique muscles. Dermatomal somatosensory evoked potentials (SEPs) exhibited prolonged latency in the right T10 and T12 dermatomes. These findings suggest that herpes zoster infection can affect both motor and sensory nerves.
Asunto(s)
Humanos , Pared Abdominal , Electromiografía , Potenciales Evocados Somatosensoriales , Exantema , Herpes Zóster , Hipoestesia , Imagen por Resonancia Magnética , Músculos , Agujas , Parálisis , Músculos Paraespinales , Paresia , Recto del Abdomen , PielRESUMEN
The nerve electrophysiological tests may differentiate the treatment of primary premature ejaculation (PPE) in our previous studies. However, no study verifies if the results will be affected by abstinence time. From January to December in 2016, fifty PPE patients ejaculated within 2 min and 28 control subjects were enrolled. The nerve electrophysiological tests, including dorsal nerve somatosensory evoked potential (DNSEP), glans penis somatosensory evoked potential (GPSEP), and penile sympathetic skin response (PSSR), were recorded before and immediately after ejaculation. The abstinence day was not correlated with the latencies of SEPs or PSSR neither in PE group (P = 0.170, 0.064, and 0.122, respectively) nor in control group (P = 0.996, 0.475, and 0.904, respectively). No statistically differences were found in the latencies of SEPs and PSSR before and after ejaculation in PE patients (P = 0.439, 0.537, and 0.576, respectively) or control subjects (P = 0.102, 0.198, and 0.363, respectively). Thus, abstinence time does not interfere with the nerve electrophysiological test, which is stable in determining the nerve function of PPE patients.
Asunto(s)
Adulto , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , Eyaculación , Estimulación Eléctrica , Fenómenos Electrofisiológicos , Potenciales Evocados Somatosensoriales , Pene/fisiopatología , Eyaculación Prematura/fisiopatología , Estudios Prospectivos , Abstinencia Sexual , Piel/inervación , Sistema Nervioso Simpático/fisiopatologíaRESUMEN
Spinal cord stimulation (SCS) is a common therapeutic technique for treating medically refractory neuropathic back and other limb pain syndromes. SCS has historically been performed using a sedative anesthetic technique where the patient is awakened at various times during a surgical procedure to evaluate the location of the stimulator lead. This technique has potential complications, and thus other methods that allow the use of a general anesthetic have been developed. There are two primary methods for placing leads under general anesthesia, based on 1) compound muscle action potentials and 2) collisions between somatosensory evoked potentials. Both techniques are discussed, and the literature on SCS lead placement under general anesthesia using intraoperative neurophysiological mapping is comprehensively reviewed.
Asunto(s)
Humanos , Potenciales de Acción , Anestesia General , Potenciales Evocados Somatosensoriales , Extremidades , Neurofisiología , Estimulación de la Médula Espinal , Médula EspinalRESUMEN
PURPOSE: To evaluate the efficacy and safety of cerebral monitoring by transcranial Doppler ultrasonography (TCD) for the detection of cerebral ischemia during carotid endarterectomy (CEA). METHODS: From August 2004 to December 2013, 159 CEAs were performed in a tertiary hospital. All procedures were performed under general anesthesia. Intraoperative TCD was routinely used to detect cerebral ischemia. Of the 159 patients, 102 patients were included in this study, excluding 27 patients who had a poor transtemporal isonation window and 30 patients who used additional cerebral monitoring systems such as electroencephalography or somatosensory evoked potentials. When mean flow velocity in the ipsilateral middle cerebral artery decreased by >50% versus baseline during carotid clamping carotid shunting was selectively performed. The carotid shunt rate and incidence of perioperative (<30 days) stroke or death were investigated by reviewing medical records. RESULTS: Carotid shunting was performed in 31 of the 102 patients (30%). Perioperative stroke occurred in 2 patients (2%); a minor ischemic stroke caused by embolism in one and an intracerebral hemorrhage in the other. Perioperative death developed in the latter patient. CONCLUSION: TCD is a safe cerebral monitoring tool to detect cerebral ischemia during CEA. It can reduce use of carotid shunt.
Asunto(s)
Humanos , Anestesia General , Isquemia Encefálica , Hemorragia Cerebral , Constricción , Electroencefalografía , Embolia , Endarterectomía Carotidea , Potenciales Evocados Somatosensoriales , Incidencia , Registros Médicos , Arteria Cerebral Media , Accidente Cerebrovascular , Centros de Atención Terciaria , Ultrasonografía Doppler TranscranealRESUMEN
OBJECTIVE: To investigate the feasibility of a knee proprioception evaluation using a dynamometer as a tool for evaluating proprioception of the lower extremities in patients with incomplete spinal cord injury (SCI), and to explore its usefulness in predicting the ambulatory outcome. METHODS: A total of 14 SCI patients (10 tetraplegic, 4 paraplegic; all AIS D) were included in this study. The passive repositioning error (PRE) and active repositioning error (ARE) were measured with a dynamometer, along with tibial somatosensory evoked potential (SSEP) and abductor hallucis motor-evoked potential (MEP). Ambulatory capacity was assessed with the Walking Index for Spinal Cord Injury II (WISCI-II), both at the time of the proprioception test (WISCI_i) and at least 6 months after the test (WISCI_6mo). RESULTS: The PRE showed a negative correlation with WISCI_i (r=-0.440, p=0.034) and WISCI_6mo (r=-0.568, p=0.010). Linear multiple regression showed the type of injury, lower extremities motor score, MEP, and PRE accounted for 75.4% of the WISCI_6mo variance (p=0.080). CONCLUSION: Proprioception of the knee can be measured quantitatively with a dynamometer in patients with incomplete SCI, and PRE was related to the outcome of the ambulatory capacity. Along with the neurological and electrophysiological examinations, a proprioception test using a dynamometer may have supplementary value in predicting the ambulatory capacity in patients with incomplete SCI.
Asunto(s)
Humanos , Potenciales Evocados Somatosensoriales , Rodilla , Extremidad Inferior , Propiocepción , Traumatismos de la Médula Espinal , Médula Espinal , CaminataRESUMEN
OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.
Asunto(s)
Humanos , Potenciales Evocados Motores , Potenciales Evocados Somatosensoriales , Hemangioma , Monitorización Neurofisiológica Intraoperatoria , Fuerza Muscular , Complicaciones Posoperatorias , Sensibilidad y Especificidad , Neoplasias de la Médula Espinal , Médula EspinalRESUMEN
<p><b>OBJECTIVE</b>To investigate the clinical features and surgical strategy for pediatric intractable epilepsy due to posterior quadrantic cortical dysplasia and to assess the surgical outcomes.</p><p><b>METHODS</b>The clinical features and preoperative evaluation results of 14 children with intractable epilepsy due to posterior quadrantic cortical dysplasia were retrospectively analyzed. The localization values of video-electroencephalography and intraoperative monitoring and the indications, advantages and disadvantages of temporoparietooccipital disconnection were evaluated.</p><p><b>RESULTS</b>The 14 children had different seizure types, of which spasm was the most common one. The lesions of cortical dysplasia involved the central cerebral region in 2 cases. After temporoparietooccipital disconnection in 14 patients, 13 cases were seizure-free; only one case still had seizures, but the frequency dropped by more than 50%.</p><p><b>CONCLUSIONS</b>Temporoparietooccipital disconnection is a safe and effective surgical procedure for children with intractable epilepsy due to posterior quadrantic cortical dysplasia.</p>
Asunto(s)
Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Electroencefalografía , Epilepsia , Cirugía General , Potenciales Evocados Somatosensoriales , Malformaciones del Desarrollo CorticalRESUMEN
STUDY DESIGN: Prospective cohort study. PURPOSE: This study was to investigate interside asymmetries of three lower extremity somatosensory evoked potentials (SSEPs) in anesthetized patients with unilateral lumbosacral radiculopathy. OVERVIEW OF LITERATURE: Although interside asymmetry is an established criterion of abnormal SSEP, little is known which of the lower SSEPs is more sensitive in detecting interside asymmetry in anesthetized patients. METHODS: Superficial peroneal nerve SSEP (SPN-SSEP), posterior tibial nerve SSEP (PTN-SSEP), and sural nerve SSEP were obtained in 31 lumbosacral surgery patients with unilateral lumbosacral radiculopathy, and compared with a group of 22 control subjects. RESULTS: The lumbosacral group showed significant larger interside asymmetry ratios of P37 latencies in SPN-SSEP and PTN-SSEP, and significant larger interside asymmetry ratio of P37-N45 amplitude in SPN-SSEP, when comparing with the control group. Within the lumbosacral group but not the control group, SPN-SSEP displayed significant larger interside asymmetry ratio in P37 latency. When referencing to the control group, more patients in the lumbosacral group displayed abnormal interside SPN-SSEP latency asymmetries which corroborated the symptom laterality. CONCLUSIONS: The data suggested that SPN-SSEP was more sensitive in detecting interside latency asymmetry in anesthetized patients.
Asunto(s)
Humanos , Estudios de Cohortes , Potenciales Evocados Somatosensoriales , Extremidad Inferior , Nervio Peroneo , Estudios Prospectivos , Radiculopatía , Nervio Sural , Nervio TibialRESUMEN
<p><b>OBJECTIVE</b>To investigate the role of short-latency somatosensory evoked potential (SSEP) in the diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP).</p><p><b>METHODS</b>A 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.</p><p><b>RESULTS</b>Among 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).</p><p><b>CONCLUSIONS</b>SSEP can be used for the auxiliary diagnosis of CIDP, especially in CIDP children with affected sensory nerves or secondary axonal degeneration.</p>
Asunto(s)
Niño , Preescolar , Femenino , Humanos , Masculino , Axones , Fisiología , Potenciales Evocados Somatosensoriales , Polirradiculoneuropatía Crónica Inflamatoria Desmielinizante , Diagnóstico , Tiempo de ReacciónRESUMEN
ABSTRACT Objective The evaluation of selective activation of C-fibers to record evoked potentials using the association of low-power diode laser (810 nm), tiny-area stimulation and skin-blackening. Method Laser-evoked potentials (LEPs) were obtained from 20 healthy young subjects. An aluminum plate with one thin hole was attached to the laser probe to provide tiny-area stimulation of the hand dorsum and the stimulated area was covered with black ink. Results The mean intensity used for eliciting the ultra-late laser-evoked potential (ULEP) was 70 ± 32 mW. All subjects showed a clear biphasic potential that comprised a negative peak (806 ± 61 ms) and a positive deflection (1033 ± 60 ms), corresponding to the ULEP related to C-fiber activation. Conclusion C-fiber-evoked responses can be obtained using a very low-power diode laser when stimulation is applied to tiny areas of darkened skin. This strategy offers a non-invasive and easy methodology that minimizes damage to the tissue.
RESUMO Objetivo Avaliação da ativação de fibras C para o registro de potenciais evocados utilizando-se laser de baixa potência, áreas pequenas de estimulação e escurecimento da pele. Método Potenciais evocados foram obtidos de 20 sujeitos. Uma placa de alumínio com uma pequena abertura foi acoplada à ponteira do laser para estimular área escurecida do dorso da mão. Resultados A intensidade média utilizada para estimulação foi de 70 ± 32 mW. Todos os sujeitos apresentaram respostas claras compreendendo dois picos um negativo (806 ± 61 ms) seguido por outro positivo (1033 ± 60 ms), correspondendo ao potencial evocado tardio por estimulação de fibras C. Conclusão Respostas de fibras C podem ser obtidas utilizando-se laser de baixa potência quando a estimulação é aplicada a pequenas áreas de pele escurecida. Esta estratégia oferece uma metodologia não invasiva que minimiza danos teciduais.
Asunto(s)
Humanos , Masculino , Femenino , Adulto , Nociceptores/efectos de los fármacos , Potenciales Evocados Somatosensoriales/efectos de la radiación , Láseres de Semiconductores , Fibras Nerviosas/efectos de la radiación , Tiempo de ReacciónRESUMEN
OBJECTIVE: The aim of this study was to investigate frontal N30 status in Parkinson's disease (PD) and to examine the correlation between the amplitude of frontal N30 and the severity of motor deficits. METHODS: The frontal N30 was compared between 17 PD patients and 18 healthy volunteers. Correlations between the amplitude of frontal N30 and the Unified Parkinson's Disease Rating Scale (UPDRS) motor score of the more severely affected side was examined. RESULTS: The mean latency of the N30 was not significantly different between patients and healthy volunteers (p = 0.981), but the mean amplitude was lower in PD patients (p < 0.025). There was a significant negative correlation between the amplitude of N30 and the UPDRS motor score (r = -0.715, p = 0.013). CONCLUSIONS: The frontal N30 status indicates the motor severity of PD. It can be a useful biomarker reflecting dopaminergic deficits and an objective measurement for monitoring the clinical severity of PD.