Brainstem auditory and somatosensory evoked potentials: a methodological study to evaluate the reproducibility of two devices.

We aimed to determine whether statistical significant differences exist between the sets of results obtained from two devices used in our department for measuring brainstem auditory evoked potentials (BAEPs) and somatosensory evoked potentials (SEPs). We obtained BAEP and median and posterior tibial nerve SEP values bilaterally in ten healthy subjects. The tests were performed on the same subject using two devices consecutively. The equipment consisted of a Nicolet Viking-IV (Nicolet, Madison, WI, USA) and a Viking Select (Viasys Healthcare, Madison, WI, USA), and the same recording electrodes and stimulator (auditory and electrical) were used without modifying any postural position of the subject. The stimuli and recording parameters were the same for both devices. We obtained 20 sets of data for each type of test. The Bland­Altman plots as well as the one-sample t-test or Wilcoxon signed rank test were used to compare data between the two groups of data sets. We found no significant differences between the sets of values obtained with the two devices. Our analysis indicates that the two devices are equal in recording all different variables of BAEP and SEP, which allows us to combine the BAEP and SEP data obtained from the two devices for follow-up studies involving quantitative statistical methods. This study received institutional approval (protocol number PRAG-154/2013).

Do multimodal evoked potentials add information to MRI in clinically isolated syndromes?

The role of multimodal evoked potentials (MMEPs) in establishing multiple sclerosis (MS) diagnosis and prognosis has diminished nowadays. The objective of this article is to evaluate whether MMEPs add information to MRI in identifying patients with higher risk of relapse or development of disability after a clinically isolated syndrome (CIS). Patients who underwent visual, somato-sensory and brainstem auditory evoked potentials (EPs) were identified from a cohort of consecutive CIS. Patients also underwent brain MRI within 3 months of first attack. We analysed time to second attack and to Expanded Disability Status Scale (EDSS) score of 3.0 according to number of Barkhof criteria and number of abnormal MMEPs. A complete study was performed in 245 patients who were followed for a mean of 76.4 months (interquartile range: 61 to 96). Seventy-one patients (29%) had the three EPs normal, 115 patients (47%) had one abnormal EP; 40 patients (16%) had two; and 19 patients (8%) had three abnormal EPs. Baseline MRI determined the risk for converting to clinically definite MS and correlated with disability according to previous studies. EPs individually did not modify the risk of conversion or disability. However, the presence of three abnormal EPs increased the risk of reaching moderate disability (hazard ratio 7.0; 1.4-34.9) independently of baseline MRI. In conclusion, in the presence of three abnormal EPs could help identify CIS patients with a higher risk of developing disability, independently of MRI findings. However, the utility of MMEPs is limited by the low percentage of CIS patients having the three abnormal at baseline.

[Detection of episodes of ischemic tissue hypoxia by means of the combined intraoperative neurophysiologic monitoring with the tissue oxygenation monitoring in aneurysm surgery]. / Detección de episodios de hipoxia tisular isquémica mediante la monitorizaciónneurofisiológica intraoperatoria combinada con la monitorización de la oxigenacióntisular en la cirugía aneurismática.

INTRODUCTION: Intraoperative neuromonitoring in aneurysm surgery can be very useful to determine inadequate positions of the vascular clip that cause partial or complete compromise of the cerebral sanguineous flow in the vascular territories irrigated by the arteries related to aneurysm. The direct visualization of these arteries after the application of the surgical clip can be insufficient in detecting this potentially detrimental situation. Knowing this circumstance on the onset would allow the neurosurgeon to correct it and to avoid, therefore, cerebral ischemic tissue hypoxia. We show the utility of the intraoperative monitoring of the oxygen tissue pressure (PtiO2) and the somatosensorial evoked potential (SSEP) for the detection of these situations with the example of a clinical case. CLINICAL CASE: We present the case of a 62 year-old woman, that presented with subarachnoid hemorrhage of aneurysmal origin. The cerebral arteriography demonstrated the existence of an aneurysm of the posterior communicating artery that was treated initially by endovascular procedure with partial exclusion of the aneurysm. For this reason it was decided to complete the treatment with a programmed surgery. The patient was put on an intraoperative monitoring system with a PtiO2 sensor located in the risk area and with SSEP. After positioning the surgical clip the partial oxygen pressure decreased rapidly, as well as the amplitude of the cortical potential of the left posterior tibial nerve. The knowledge of this situation allowed the detection of a trapped posterior communicating artery. After correcting this situation by replacing the surgical clip, both variables recovered to their basal values. CONCLUSIONS: The intraoperative PtiO2 monitoring, combined with neurophysiologic monitoring during aneurysm surgery offers a fast and trustworthy form of early detection of ischemic phenomena caused by bad positioning of the surgical clip.

Detección de episodios de hipoxia tisular isquémica mediante la monitorización neurofisiológica intraoperatoria combinada con la monitorización de la oxigenación tisular en la cirugía aneurismática / Detection of episodes of ischemic tissue hypoxia by means of the combined intraoperative neurophysiologic monitoring with the tissue oxygenation monitoring in aneurysm surgery

Introducción. La neuromonitorización intraoperatoria en la cirugía aneurismática puede ser de gran utilidad para determinar posiciones inadecuadas del clip que ocasionen un compromiso parcial o completo del flujo sanguíneo cerebral en los territorios vasculares irrigados por las arterias relacionadas con el aneurisma. La visualización directa de estas arterias tras la aplicación del clip quirúrgico puede ser insuficiente para detectar esta situación potencialmente deletérea. El conocimiento precoz de esta circunstancia permitiría al neurocirujano corregirla y evitar así la hipoxia tisular cerebral isquémica. Mostramos, con el ejemplo de un caso clínico, la utilidad de la monitorización intraoperatoria de la presión tisular de oxígeno (PtiO2) y de los potenciales evocados somato sensoriales (PESS) para la detección de estas situaciones. Caso clínico. Presentamos el caso de una mujer de 62 años de edad, que debutó con una hemorragia subaracnoidea de origen aneurismático. La arteriografía cerebral demostró la existencia de un aneurisma de la arteria comunicante posterior izquierda que fue tratado inicialmente por vía endovascular con exclusión parcial del aneurisma. Por este motivo se decidió completar el tratamiento mediante cirugía programada. La paciente fue monitorizada intraoperatoriamente con un sensor de PtiO2 situado en el área de riesgo y con PESS. Tras la colocación del clip se produjo una rápida caída de la presión parcial de oxígeno, así como disminución de la amplitud del potencial cortical del nervio tibial posterior izquierdo. El conocimiento de esta situación, permitió detectar un atrapamiento de la arteria comunicante posterior. Tras corregir esta situación reposicionando el clip quirúrgico, ambas variables recuperaron sus valores basales. Conclusiones. La monitorización intraoperatoria dela PtiO2 combinada con la monitorización neurofisiológica durante la cirugía aneurismática ofrece, de una forma rápida y fiable, la detección precoz de fenómenos isquémicos ocasionados por mal posicionamiento del clip quirúrgico

Introduction. Intraoperative neuromonitoring in aneurysm surgery can be very useful to determine inadequate positions of the vascular clip that cause partial or complete compromise of the cerebral sanguineous flow in the vascular territories irrigated by the arteries related to aneurysm. The direct visualization of these arteries after the application of the surgical clip can be insufficient in detecting this potentially detrimental situation. Knowing this circumstance on the onset would allow the neurosurgeon to correct it and to avoid, therefore, cerebral ischemic tissue hypoxia. We show the utility of the intraoperative monitoring of the oxygen tissue pressure (PtiO2) and the somato sensorial evoked potential (SSEP) for the detection of these situations with the example of a clinical case. Clinical case. We present the case of a 62 year-old woman, that presented with subarachnoid hemorrhage of aneurysmal origin. The cerebral arteriography demonstrated the existence of an aneurysm of the posterior communicating artery that was treated initially by endovascular procedure with partial exclusion of the aneurysm. For this reason it was decided to complete the treatment with a programmed surgery. The patient was put on an intraoperative monitoring system with a PtiO2 sensor located in the risk area and with SSEP. After positioning the surgical clip the partial oxygen pressure decreased rapidly, as well as the amplitude of the cortical potential of the left posterior tibial nerve. The knowledge of this situation allowed the detection of a trapped posterior communicating artery. After correcting this situation by replacing the surgical clip, both variables recovered to their basal values. Conclusions. The intraoperative PtiO2 monitoring, combined with neurophysiologic monitoring during aneurysm surgery offers a fast and trustworthy form ofearly detection of ischemic phenomena caused by bad positioning of the surgical clip

Bilateral optic nerve atrophy in myotonic dystrophy.

PURPOSE: To document a case of bilateral optic atrophy in a patient with myotonic dystrophy. Myotonic dystrophy is an autosomal dominant disorder, genetically resulting from an expansion of an unstable CTG repeat in the 3'-untranslated region of a protein kinase gene (DMPK) on chromosome 19q13.3. METHODS: Case report, clinical examination, fundus photographs, visual fields, visual evoked potentials, electroretinograms, and genetic studies of a 56-year-old woman clinically diagnosed with myotonic dystrophy. RESULTS: The patient experienced decreased vision consisting of light perception with the right eye and 20/25 with the left. Fundus examination showed bilateral pallor of the optic disks. Intraocular pressure was normal. Visual field testing, visual evoked potentials, and electroretinogram were abnormal. A pathologic CTG expansion in the myotonic dystrophy gene was found. CONCLUSIONS: In a patient with myotonic dystrophy, confirmed with genetic molecular diagnosis, bilateral optic atrophy was present. Optic atrophy should be considered a possible complication of myotonic dystrophy.

Ophthalmologic findings in a patient with cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy.

PURPOSE: To determine the ophthalmologic findings in a 39-year-old woman with the Boucher-Neuhäuser syndrome, which is a disorder of autosomal recessive inheritance characterized by the triad of spinocerebellar ataxia, chorioretinal dystrophy, and hypogonadotropic hypogonadism. METHODS: The patient underwent clinical and electrophysiologic examinations and fluorescein angiography. RESULTS: The main clinical findings were extensive areas of retinal pigment epithelial and choriocapillaris atrophy affecting the posterior pole and midperiphery of both eyes. Results of electroretinographic examination showed subnormal photopic and scotopic responses. CONCLUSIONS: The Boucher-Neuhäuser syndrome should be included in the differential diagnosis of patients with chorioretinal degeneration, particularly if there are neurologic or endocrinologic manifestations.

[Developmental study of the paroxysmal tracing in the full term neonate (author's transl)]. / Etude évolutive du tracé paroxystique chez le nouveau-né a terme.

The development of the paroxysmal trace was studied in 13 full term neonates having presented with severe neonatal anoxia. The paroxysmal tracings according to the definition given by by Monod and Dreyfus-Brisac changed between the 10th and 15th days, the bursts of waves being more polymorphic and closer together but the paroxysmal component persisted. Further groups of anterior slow waves symmetrical and limited to the mid temporal region appeared. These patterns disappeared between the 2nd and 3rd month to make way for generalised spikes and resembling hypsarrhythmia beyond the third month.