Somatosensory Evoked Potentials In Children Research Articles

The Prognostic Value of Somatosensory Evoked Potentials in Children After Cardiac Arrest: The SEPIA Study.

Absent cortical somatosensory evoked potentials (SSEPs) reliably predict poor neurologic outcome in adults after cardiac arrest (CA). However, there is less evidence to support this in children. In addition, targeted temperature management, test timing, and a lack of blinding may affect test accuracy. A single-center, prospective cohort study of pediatric (aged 24 hours to 15 years) patients in which prognostic value of SSEPs were assessed 24, 48, and 72 hours after CA. Targeted temperature management (33-34°C for 24 hours) followed by gradual rewarming to 37°C was used. Somatosensory evoked potentials were graded as present, absent, or indeterminate, and results were blinded to clinicians. Neurologic outcome was graded as "good" (score 1-3) or "poor" (4-6) using the Pediatric Cerebral Performance Category scale 30 days after CA and blinded to SSEP interpreter. Twelve patients (median age, 12 months; interquartile range, 2-150; 92% male) had SSEPs interpreted as absent (6/12) or present (6/12) <72 hours after CA. Outcome was good in 7 of 12 patients (58%) and poor in 5 of 12 patients (42%). Absent SSEPs predicted poor outcome with 88% specificity (95% confidence interval, 53% to 98%). One patient with an absent SSEP had good outcome (Pediatric Cerebral Performance Category 3), and all patients with present SSEPs had good outcome (specificity 100%; 95% confidence interval, 51% to 100%). Absence or presence of SSEP was consistent across 24-hour (temperature = 34°C), 48-hour (t = 36°C), and 72-hour (t = 36°C) recordings after CA. Results support SSEP utility when predicting favorable outcome; however, predictions resulting in withdrawal of life support should be made with caution and never in isolation because in this very small sample there was a false prediction of unfavorable outcome. Further prospective, blinded studies are needed and encouraged.

Multimodality monitoring of transcranial electric motor and somatosensory-evoked potentials during surgical correction of spinal deformity in patients with cerebral palsy and other neuromuscular disorders.

This prospective, descriptive study determined the reliability of transcranial electric motor and posterior tibial nerve somatosensory-evoked potentials in children with neuromuscular scoliosis. To assess the applicability of transcranial electric motor and posterior tibial nerve somatosensory-evoked potentials during surgical correction of neuromuscular scoliosis, particularly with cerebral palsy-related deformity. During corrective spinal surgery for neuromuscular scoliosis, intraoperative multimodality spinal cord monitoring is recommended. There exist conflicting, retrospective studies regarding the reliability of spinal cord monitoring in patients with neuromuscular scoliosis. Transcranial electric motor potentials and posterior tibial nerve somatosensory-evoked potentials were monitored in all patients presenting for spinal fusion between 2000 and 2001. Anesthesia was standardized for all patients. There were 68 patients subdivided into two subject groups. Group I consisted of 39 patients with neuromuscular scoliosis associated with cerebral palsy, and Group II consisted of 29 children with neuromuscular scoliosis due to a disease process other than cerebral palsy. Five of the 68 patients had significant amplitude changes in 1 or both monitoring methods during surgery relative to baseline. Of these, one had permanent neurologic deficit despite standard intervention. Somatosensory-evoked potentials were monitored successfully in 82% of the cerebral palsy and 86% of the noncerebral palsy patients. Transcranial electric motor-evoked potentials, on the other hand, were monitorable in 63% of patients with mild or moderate degrees of cerebral palsy and 39% of those with severe involvement. Eighty-six percent of those with noncerebral palsy-related neuromuscular scoliosis had recordable motor-evoked potentials at baseline. Both transcranial electric motor and posterior tibial nerve somatosensory-evoked potentials can be monitored reliably in most patients with neuromuscular scoliosis. Those with severe cerebral palsy present the greatest challenge to successful neurophysiologic monitoring.

Fiberoptic Intubation And Monitoring Of Somatosensory Evoked Potentials In Children With Mucopolysaccharidoses

The management of children with mucopolysaccharidosis (MPS) is a challenge for the anesthesiologist, primarily because of difficult airways. Furthermore, cert ain types of MPS (I,VI, VII) are at risk for cervical spine compression. Theref ore, we recommend monitoring of somatosensory potentials during intubation and during positioning of these patient for surgery. Two case reports are presented to demonstrate the perioperative management. Water intoxication (restlessness, frothing, retching, tremor and twitching of muscles) was first described by Wier et al. in 1922 (1). In 1998 we are still diagnosing and treating iatrogenic water intoxication described as TURP Syndrome. The presented case describes a typical TURP syndrome, which was diagnosed early, treated aggressively, and which led to a good outcome for the patient. Transurethral resection of the prostate consists of removal of prostatic tissue by means of electro-cautery. The electrocautery wire loop is positioned in the patient’s urethra through a special sheath. The surgical field is visualized through a scope. Irrigation solution is used to distend the bladder, clear the surgical site, and remove blood and resected tissue. Normal saline cannot be used as irrigation solution because the dissemination of the electric current would be dangerous to both, surgeon and patient. A variety of irrigation solutions have been used in the past. 80 min into the case the patient was noted to be markedly hypothermic. This may reflect the large amount of cold solute absorbed by the patient and confirmed by the Na measurement of 109 mEq/L. A decrease in serum Na of 20-30 mEq/L (preoperative Na was 138 mEq/L) implies absorption of 3-4 liters of fluid (dilutional hyponatremia) (2). All other vital signs remained stable. Another clue to a hypervolemic state might be hypertension and reflex bradycardia. Several factors contribute to the rapid volume expansion, namely the intravesicular pressure (governed by the height of the irrigation bag above the prostatic sinuses), the number of prostatic sinuses opened and maybe most important the duration of the surgical procedure. Surgery was terminated at this point and the patient was transferred intubated and sedated to the ICU. Figure 1 Chest X-ray at arrival SICU: Slightly incresed pulmonary vasculature suggesting fluid overload. Fiberoptic Intubation And Monitoring Of Somatosensory Evoked Potentials In Children With Mucopolysaccharidoses 2 of 4 Figure 2 EKG at arrival SICU: Sinus bradycardia of 52 bpm without QTor STabnormalities The patient was still intubated and sedated. Therefore, we were unable to assess his neurological function, but we can assume that secondary to his profound hyponatremia, hypoosmolality and high ammonia levels he would have had some neurological abnormality. Some anesthesiologists and urologists would prefer regional (epidural or spinal anesthesia) compared to general anesthesia in order to early recognize mental changes in their awake patients. Neurologic changes (confusion, agitation, or other mental changes) are among the first clinical signs of water intoxication. Early recognition and early treatment of a TURP syndrome is an extremely important factor in its therapy. Neurological symptoms vary through a spectrum from mild confusion and encephalopathy through to seizures and coma. The neurological effects may result from cerebral edema associated with acute hypotonicity or from toxicity of glycine. If glycine concentrations are 30 times the normal value, visual impairment may occur (2). Visual impairment also ranges across a spectrum from blurred vision through blindness, as glycine is a major inhibitory neurotransmitter in the retina (3). Our patient did exhibit some confusion and agitation after awakening. This resolved completely within 48 hours. No visual impairment was noted. The patient was extubated after 24 hours. The vital signs were stable, the lung clear to bilateral auscultation, and the chest x ray negative for pulmonary edema. Figure 3 Chest X-ray after 24 hours in SICU:

Median nerve middle-long latency somatosensory evoked potentials in children with tactile evoked spikes.

It is known that hand tapping during electroencephalography (EEG) recording evokes centrotemporal spikes in some 4- to 12-year-old children. This phenomenon occurs in both healthy and epileptic children. The same children were reported to show giant middle-long latency evoked potentials (MLSEPs). To study the relationship between tactile evoked spikes (TES) and MLSEPs, we performed a neurophysiologic investigation in 25 children with TES and in 25 children without any EEG abnormality. Such an investigation included a MLSEP study after both electrical and tactile stimulation with simultaneous recording of digital EEG. MLSEPs consistently showed three negative (NI, NII, NIII) and two positive (PI, PII) peaks. Children with TES had MLSEPs of enlarged amplitude. The analysis of MLSEPs and TES characteristics led us to the conclusion that they are the same neurophysiologic event, with NII being the evoked spike and NIII the following slow-wave.

Cotrel-dubousset instrumentation in children using simultaneous motor and somatosensory evoked potential monitoring.

To record prospectively combined motor- and somatosensory-evoked potentials in children during scoliosis surgery using Cotrel-Dubousset instrumentation, without using special anesthetic or muscle relaxant regimens. To determine the outcome of scoliosis surgery guided by a new technique of monitoring motor- and somatosensory-evoked potentials simultaneously. Other techniques used to assess cord function generally are limited by special anesthetic requirements or assess only a limited part of the cord or monitor motor function separately from somatosensory function. Spinal cord function was monitored using epidural leads to record simultaneously the descending motor volley (by transcranial electrical stimulation) and the ascending somatosensory volley (by tibial nerve stimulation) at two spinal levels. Combined motor- and sensory-evoked potentials were recorded successfully in 138 of 160 children (81%). Changes in evoked potential waveforms were seen in eight patients (5%), but resolved or lessened in response to appropriate measures. Curve correction was satisfactory, and there were no new postoperative deficits or worsening of preexisting deficits in any patient. A spinal cord monitoring system is described that is safe, reliable, accurate, and makes it unnecessary to resort to the "wake-up" test.

Short latency somatosensory-evoked potentials in children —part 3. Findings following head injury

Fourteen children aged 3 to 11 years who suffered from coma for at least 6 hours had somatosensory-evoked potential studies performed within 24 hours of neurotrauma. The upper cervical (Cv2) and bilateral cortical somatosensory-evoked potentials were recorded for calculation of the central somatosensory conduction time. Despite the fact that the SEP recordings were performed in the intensive care unit and the patients were receiving opiate and barbiturate therapy, satisfactory somatosensory-evoked potentials were recorded in all patients. Symmetrical short latency cortical somatosensory-evoked potentials were recorded bilaterally in 10 patients. Two patients with hemorrhagic cerebral contusions and unilateral cerebral edema had ipsilateral abnormalties of the cortical somatosensoryevoked potential. These patients all had normal central somatosensory conduction times and all had satisfactory neurological recoveries, although the two patients with abnormal cortical somatosensory-evoked potentials had focal neurological deficits. Two patients whose head injuries were complicated by hypoxia and refractory intracranial hypertension had bilaterally abnormal cortical somatosensory-evoked potentials, and both had vegetative outcomes. There was no correlation between the Glasgow Coma Score and central somatosensory conduction time; however, the number of components to the cortical somatosensory-evoked potential was related to the Glasgow Coma Score. The results suggest that the recording of somatosensory-evoked potentials can provide useful information about the functional status of central and cortical somatosensory pathways in children following major head injury.

Short latency somatosensory-evoked potentials in children —part 4. Findings with cerebral lesions

Cortical somatosensory-evoked potential studies were performed on seven children with unilateral intracerebral lesions. Three patients had neoplasms, and four had hematomas of various etiology. All the lesions involved either directly or indirectly with the thalamocapsular or perirolandic regions of the brain. Patterns of somatosensoryevoked potential asymmetry included abnormality of the primary cortical complex (NI-PI), loss of intermediate and long latency waveform components, and attenuation of the response on the side of the lesion. The most abnormal somatosensory-evoked potentials were seen in patients with major clinical deficits, whereas patients with minimal neurologic signs had minor somatosensory-evoked potential changes. The location, etiology, and duration of the lesion all appeared to influence the somatosensory-evoked potential waveform. The value of somatosensory-evoked potential studies in the diagnosis and localization of cerebral lesions would seem to be limited because of pathophysiologic phenomena related to the primary cerebral lesion.

Short latency somatosensory-evoked potentials in children —part 1 normative data

Spinal, subcortical, and short latency cortical somatosensory-evoked potentials (SEPs) following electrical stimulation of the median or tibial nerve were studied in 100 children aged 4 weeks to 13 years. Standard neurophysiological methods of recording surface SEPs were used in sedated and nonsedated children. The morphology of the SEPs was similar to that obtained in adults; however, the initial components of the cortical SEP following median nerve stimulation did show maturational changes in both interpeak latencies and morphology. The negative peak latencies recorded over Erb's point (N9 equivalent) and the second cervical vertebra (N13 equivalent) following median nerve stimulation, and over the lumbothoracic junction (N14 equivalent) following tibial nerve stimulation were directly related to patient age and limb length. There was no correlation between age and the latencies of either the initial negativity (N18 equivalent) or the initial positivity (P28 equivalent) of the cortical SEPs following respective median and tibial nerve stimulation. The central somatosensory conduction time decreased slowly during the first decade and attained adult values after 8 years of age. The lumbar spine to scalp transit time showed no direct relationship to age. Comparisons of SEPs recorded in the same subject when awake and under general anesthesia showed that the latencies of the subcortical, spinal, and Nl-Pl complex of the cortical SEP are identical; however, the later components of the cortical SEP vary both in latency and amplitude with anesthesia. This study represents normative data against which SEP in children with disorders of the central nervous system may be compared.

Short Latency Somatosensory Evoked Potentials in Children with Congenital Central Nervous System disorders

Short Latency Somatosensory Evoked Potentials in Children with Congenital Central Nervous System disorders