Localization of irritative zones in epilepsy with thermochromic silicone.

BACKGROUND: During epilepsy surgery, the gold standard to identify irritative zones (IZ) is electrocorticography (ECoG); however, new techniques are being developed to detect IZ in epilepsy surgery and in neurosurgery in general, such as infrared thermography mapping (ITM), and the use of thermosensitive/thermochromic materials. METHODS: In a cohort study of consecutive patients with focal drug-resistant epilepsy of the temporal lobe treated with surgery, we evaluated possible adverse effects to the transient placement of a thermochromic/thermosensitive silicone (TTS) on the cerebral cortex and their postoperative evolution. Furthermore, we compared the precision of TTS for detecting cortical IZ against the gold standard ECoG and with ITM, as proof of concept. RESULTS: We included 10 consecutive patients, 6 women (60%) and 4 men (40%). Age ranges from 15 to 56 years, mean 33.2 years. All were treated with unilateral temporal functional lobectomy. The mean hospital stay was 4 days. There were no immediate or late complications associated with the use of any of the modalities described. In the 10 patients, we obtained consistency in locating the IZ with ECoG, ITM, and the TTS. CONCLUSION: The TTS demonstrated biosecurity in this series. The accuracy of the TTS to locate IZ was similar to that of ECoG and ITM in this study. More extensive studies are required to determine its sensitivity and specificity.

[Uncertainty, dynamic systems, principles of quantum mechanics and their relationship to the health-disease process (analysis proposal).] / Incertidumbre, sistemas dinámicos, principios de mecánica cuántica y su relación con el proceso salud-enfermedad (propuesta de análisis).

The purpose of this work is to discuss the importance and possible application of some foundations of quantum mechanics in the health-disease process, considering for this, that the laws and foundations of atomic theory are the same that govern displacement in space and time in human beings. Based on the impossibility of determining the displacement of subatomic particles in a given space and time, as a consequence of not having measuring instruments for said microscales, we propose feasible that the same happens with the uncertainty generated by the times and movements of human beings in really large spaces, reason why the analysis of the temporo-spatial location of a moving subject, in a certain time and space is impossible, fact that we consider, could represent the behavior in Pandemics. The foundations of quantum mechanics that have been considered for this purpose are dynamic systems, the Schrödinger cat paradox, the Heisenberg uncertainty principle, the law of gases, times and movements, and the Maxwell-Boltzmann entropy. On the other hand, it is proposed to consider the adaptation of measurement ecis ecisión statistical procedures (decisión tree and set theory) and finally the implementation of a unitary probabilistic cube is proposed, which allows locating a subject immersed in the health process disease through three axes developed considering the definition of health stipulated by the WHO.

El presente trabajo tuvo como finalidad discutir la importancia y la posible aplicación de algunos fundamentos de la mecánica cuántica en el proceso de salud-enfermedad, considerando para esto que las leyes y fundamentos de la teoría atómica son los mismos que rigen los desplazamientos en el espacio y el tiempo en los seres humanos. Con base en la imposibilidad de determinar el desplazamiento de las partículas subatómicas en un espacio y tiempo determinado, como consecuencia de no contar con instrumentos de medición para dichas microescalas, consideramos factible que lo mismo suceda con la incertidumbre generada por los tiempos y movimientos de los seres humanos en espacios realmente grandes, por lo que el análisis de la ubicación temporo-espacial de un sujeto en movimiento, en un tiempo y en un espacio determinado, es imposible. Creemos que este hecho podría representar el comportamiento en las pandemias. Los fundamentos de la mecánica cuántica que se han considerado con dicho fin son: los sistemas dinámicos; la paradoja del gato de Schrödinger; el principio de incertidumbre de Heisenberg; la ley de gases, tiempos y movimientos; la entropía de Maxwell-Boltzmann. Por otra parte, se propone considerar la adaptación de herramientas de medición basadas en procedimientos estadísticos (árbol de decisiones y teoría de conjuntos) y, finalmente, se propone la implementación de un cubo probabilístico unitario, el cual permita ubicar a un sujeto inmerso en el proceso de salud-enfermedad mediante tres ejes desarrollados según la definición de salud estipulada por la Organización Mundial de la Salud.

[Evaluation of cisplatin ototoxicity by the audiometric curve in retinoblastoma]. / Evaluación de la ototoxicidad del cisplatino por el área bajo la curva audiométrica en retinoblastoma.

BACKGROUND: To evaluate hearing loss severity according to Brock's gradient and to compare it with the audiometric curve during cisplatin treatment in children with retinoblastoma. METHODS: This was an observational retrospective and retrolective study. Twenty children with the diagnosis of retinoblastoma under cisplatin treatment were included. Audiometric testing was performed before treatment, after the second and fourth doses, and after the final dose. RESULTS: Decreased audition was observed in 100% of the cases. Ototoxicity can be observed with cumulative doses of 240 mg/m(2) and higher. No improvement in audition was observed and the audition loss progressed from high to medium frequencies; 15% of the patients showed a grade II loss of high frequencies at the end of the second dose. This level was observed in 95% of the cases at the end of treatment. Two years after completion of therapy, no patient showed auditory recovery. Area below the curve showed higher sensitivity to identify initial auditory loss. CONCLUSIONS: Evaluation of audition with Brock's gradient can be performed. The area under the curve is a useful method to identify minor changes in serial conventional audiometry.

[Utility of the guinea pig like model of audiology studies and proposal of surgical accesses to the ear and neck]. / Utilidad del cobayo como modelo de estudios audiológicos y propuesta de accesos quirúrgicos al oído y cuello.

We discuss the utility of the guinea pig model in audiology research and describe the different surgical accesses to the middle and inner ear in order to use these techniques for the production of experimental deafness. In addition, we describe a surgical technique for laryngeal denervation. Finally, we discuss the auditory-evoked potentials obtained in newborn and mature animals, in whom experimental deafness was produced. Our purpose was to confirm the use of the guinea pig as an ideal model for audiologic studies and for neck surgery.

[Sleep alterations in childhood victims of sexual and physical abuse]. / Alteraciones del sueño en niños víctimas de abuso físico o sexual.

INTRODUCTION: The abused child syndrome is related to a variety of emotional disorders, among which are the "post-traumatic stress syndrome" and the phenomena "re-experience," which is related to disturbances of the normal sleep-wake cycle. OBJECTIVE: To determine the polysomnographic characteristics of the abused child syndrome and compare them with paired healthy children. MATERIAL AND METHODS: After two-night habituation, all-night video-digital polygraphic recordings following recommendations of the International Federation of Clinical Neurophysiology were performed in 15 abused child syndrome and 15 healthy controls. RESULTS: In the abused child syndrome patients, the main sleep changes were decreased sleep efficiency, decreased sleep onset sleep latency, increased wakefulness, decreased REM sleep and total sleep time. CONCLUSIONS: The abused child syndrome have abnormal sleep patterns, independent of the type of abuse, age or sex. Sleep alterations are a new characteristic of the abused child syndrome, not previously described.

Distortion product otoacoustic emissions test is useful in children undergoing cisplatin treatment.

BACKGROUND: Cisplatin is a widely used chemotherapy agent that has several adverse effects, such as ototoxicity. Evaluation of hearing loss due to cisplatin therapy in children is difficult. The purpose of this study was to compare the validity of distortion product otoacoustic emissions (DPOAEs) with pure tone audiometry (PTA) in assessing hearing loss in children under cisplatin therapy. METHODS: We reviewed the files of 26 children aged between 2 and 15 years; 14 were girls. All were under treatment with cisplatin for malignancy. PTA and DPOAEs were obtained at the same session. Three subjects were studied twice; thus, there were 29 sets of studies. RESULTS: Determining a cut-off point at 45 dB HL for PTA and 4 dB SPL difference for DPOAEs, diagnostic specificity for the latter was 0.97 while sensitivity was 0.57. CONCLUSIONS: DPOAEs represent a highly valuable test for evaluating hearing loss due to cisplatin treatment. DPOAEs is a quick and objective hearing assessment method not requiring much cooperation from children.

[Effects of Cisplatin on Auditory Function in Children with cancer. Otoacoustic Emission Evaluation]. / Efectos del cisplatino en la función auditiva en niños con cáncer. Evaluación por emisiones otoacústicas.

This study was done to ascertain prospectively whether distortion product-evoked otoacoustic emissions (DP-EOAE) might detect changes in specific frequencies damaged in inner ear function earlier, before they become permanent after cisplatinum exposure for cancer treatment in children. Sixteen children treated with cisplatinum for various types of cancer were repeatedly evaluated after each chemotherapy session; results were compared to 44 controls. We observed a progressive damage in auditory function. In second assessment 50% of DP-EOAE studies were abnormal; in the third study, 66% were abnormal, and in the fourth test 71% were abnormal. Our results suggest that DP-EOAE are useful tests for earlier auditory changes induced by cisplatinum therapy; higher frequencies are the most affected, and we propose that DP-EOAE be a mandatory test before treatment and during cisplatinum therapy to detect or diagnose early hearing loss.

[Use and production of biomedical models in the field of audiology]. / Producción y uso de modelos animales en el campo de la audiología.

Presently paper mentions the importance that has the use and the production of animal models in scientific research, the relevance that has its use to be able to make a good pursuit in the research, highlighting as well as to facilitate the reproductive of the study in question. Lastly it is mentioned the models more used in the field of the audiology.

[Communication and auditory behavior obtained by auditory evoked potentials in mammals, birds, amphibians, and reptiles]. / Comunicación y comportamiento auditivo obtenidos por medio de los potenciales evocados auditivos en mamíferos, aves, anfibios y reptiles.

ANIMALS: amphibians, Frog catesbiana (frog bull, 30 animals); reptiles, Sceloporus torcuatus (common small lizard, 22 animals); birds: Columba livia (common dove, 20 animals), and mammals, Cavia porcellus, (guinea pig, 20 animals). With regard to lodging, all animals were maintained at the Institute of Human Communication Disorders, were fed with special food for each species, and had water available ad libitum. Regarding procedure, for carrying out analysis of auditory evoked potentials of brain stem SPL amphibians, birds, and mammals were anesthetized with ketamine 20, 25, and 50 mg/kg, by injection. Reptiles were anesthetized by freezing (6 degrees C). Study subjects had needle electrodes placed in an imaginary line on the half sagittal line between both ears and eyes, behind right ear, and behind left ear. Stimulation was carried out inside a no noise site by means of a horn in free field. The sign was filtered at between 100 and 3,000 Hz and analyzed in a computer for provoked potentials (Racia APE 78). RESULTS: In data shown by amphibians, wave-evoked responses showed greater latency than those of the other species. In reptiles, latency was observed as reduced in comparison with amphibians. In the case of birds, lesser latency values were observed, while in the case of guinea pigs latencies were greater than those of doves but they were stimulated by 10 dB, which demonstrated best auditory threshold in the four studied species. Last, it was corroborated that as the auditory threshold of each species it descends conforms to it advances in the phylogenetic scale. CONCLUSIONS: Beginning with these registrations, we care able to say that response for evoked brain stem potential showed to be more complex and lesser values of absolute latency as we advance along the phylogenetic scale; thus, the opposing auditory threshold is better agreement with regard to the phylogenetic scale among studied species. These data indicated to us that seeking of auditory information is more complex in more evolved species.

[Perioperative lesions in lower extremity peripheral nerves]. / Lesiones perioperatorias en nervios periféricos de extremidades inferiores.

OBJECTIVE: To review the actual concepts concerning perioperative nerve injuries during surgical or anesthetic procedures. MATERIAL AND METHODS: A summary of published medical literature from Medline search files and published reviews. CONFLICT IF INTEREST: We have not conflicts of interest. RESULTS: Perioperative nerve injuries during surgical and anesthetic procedures of the lower extremities are the most common. Many possible etiologies have been proposed to explain perioperative nerve injury and include stretch, compression, and ischemia. Commonly this injuries are under recognition and an important aspect of perioperative nerve injuries is that they can occur for multiple reasons. It is necessary to have a good communication among surgeons, neurologists and clinical neurophysiologists, so it can lead to a more detailed neurological assessment with transoperative procedures that may prevent such injuries.

Propuesta para la determinación del cambio de velocidad, velocidad instantánea y aceleración con base en el puntaje APACHE II en pacientes en estado crítico / Proposal for the determination of velocity change, instantaneous velocity and aceleration from the APACHE II score in critically ill patients / Proposta para a determinação da mudança de velocidade, velocidade instantânea e aceleração baseada no escore APACHE II em pacientes críticos

Resumen: Las herramientas de evaluación de la gravedad en el enfermo grave proporcionan información objetiva intra e interobservador relacionada con la gravedad de la enfermedad, su evolución en relación al tiempo y la estratificación de riesgo son parte fundamental en la toma de decisiones. El objetivo de este trabajo es presentar una nueva propuesta de la evaluación del APACHE II basada en un modelo matemático de cambio en el tiempo/velocidad, velocidad instantánea y aceleración.

Abstract: The illness severity scoring systems provide objetive measures for inter and intra comparisons with time, provide useful information for comparing the severity of illness are an essencial part of the improvment in clinical decisions and in stratifying patients. Appropiated application of these models helps in decision making at the right time. The aim of this paper is to submit a proposal for the evaluation of the APACHE II score based on a vectorial mathematical model of chance in time/velocity, instant velocity and aceleration.

Resumo: Os instrumentos de avaliação da gravidade do paciente grave fornecem informações objetivas intra e interobservadores relacionadas à gravidade da doença, sua evolução em relação ao tempo, estratificação de risco são fundamentais para tomada de decisão. O objetivo deste trabalho é apresentar uma nova proposta para a avaliação do APACHE II baseada em um modelo matemático de mudança de tempo/velocidade, velocidade instantânea e aceleração.

Neurophysiological monitoring in spinal cord surgery.

BACKGROUND: Intraoperative neurophysiological monitoring (IOM) during spine surgery consists of several functional tests including somatosensory evoked potentials (SSEPs), motor evoked potentials (MEPs), dermatomal potentials (DPs) and EMG (electromyography). Permanent neurological damage after spine surgery performed without intraoperative neurophysiological monitoring is frequent and often very costly. The main goal of IOM is the immediate detection, prevention and correction of neurological damage during surgery, which may go unnoticed without using these tests. METHODS: A total of 351 clinical files of patients with spinal surgery and continuous neurophysiological monitoring were transversally and descriptively reviewed from 2007 to 2008. RESULTS: There were 135 male patients (38.46%) and 216 female patients (61.54%); 82% of the cases were osteodiscal pathology with or without medullar involvement, 12% were patients with traumatic injuries, 4% with scoliosis and 2% had medullary tumors. Regarding localization, 62.1% were lumbar, 33% cervical, 4.3% thoracic and 0.5% sacral involvement; 12.4% of our cases showed significant improvement of the basal responses on SSEPs, and 56.8% showed no significant change during the procedure. In 28.4% of the cases, the surgical team had to be advised of potential neurological damage and in 2.4% there was absence of neurophysiological responses. No patient showed complete loss of any neurophysiological response. All patients reported clinical improvement after hospital discharge. CONCLUSIONS: Intraoperative neurophysiological monitoring may help avoid certain neurological risks during spine surgery, which may go unnoticed without the use of this technique.

Vigilancia neurofisiológica transoperatoria multimodal en cirugía de columna / Neurophysiological monitoring in spinal cord surgery

Introducción: La vigilancia neurofisiológica durante la cirugía de columna vertebral y de la médula espinal consiste en pruebas de potenciales evocados somatosensoriales, potenciales motores musculares, potenciales dermatomales y electromiografía. El riesgo de daño neurológico permanente después de una cirugía medular sin monitorización es significativo y el costo alto. El objetivo de la vigilancia neurofisiológica es identificar, prevenir y corregir de forma inmediata el daño neurológico que puede pasar inadvertido durante la cirugía de columna vertebral y médula espinal. Material y métodos: Estudio transversal, observacional y descriptivo de los pacientes sometidos a cirugía de columna entre 2007 y 2008 con vigilancia neurofisiológica transoperatoria. Resultados: La muestra estuvo integrada por 351 pacientes, 135 del sexo masculino (38.46 %) y 216 del femenino (61.54 %); 82 % correspondió a patología osteodiscal con o sin afectación medular, 12 % a etiología traumática, 4 % a corrección de escoliosis y 2 % a tumores medulares; por localización, 62.1 % a patología lumbar, 33 % a cervical, 4.3 % a nivel dorsal y 0.5 % a nivel sacro. El 12.4 % de los pacientes presentó mejoría de la respuesta basal de sus potenciales evocados somatosensoriales; 56.8 % los mantuvo similares a sus controles prequirúrgicos, 28.4 % requirió llamada de alerta al cirujano por riesgo de daño y 2.4 % caída severa de respuesta. En ningún caso hubo pérdida permanente. Conclusiones: La vigilancia neurofisiológica constituye una herramienta de gran valor que evita daños que pueden producirse durante esta cirugía.

BACKGROUND: Intraoperative neurophysiological monitoring (IOM) during spine surgery consists of several functional tests including somatosensory evoked potentials (SSEPs), motor evoked potentials (MEPs), dermatomal potentials (DPs) and EMG (electromyography). Permanent neurological damage after spine surgery performed without intraoperative neurophysiological monitoring is frequent and often very costly. The main goal of IOM is the immediate detection, prevention and correction of neurological damage during surgery, which may go unnoticed without using these tests. METHODS: A total of 351 clinical files of patients with spinal surgery and continuous neurophysiological monitoring were transversally and descriptively reviewed from 2007 to 2008. RESULTS: There were 135 male patients (38.46%) and 216 female patients (61.54%); 82% of the cases were osteodiscal pathology with or without medullar involvement, 12% were patients with traumatic injuries, 4% with scoliosis and 2% had medullary tumors. Regarding localization, 62.1% were lumbar, 33% cervical, 4.3% thoracic and 0.5% sacral involvement; 12.4% of our cases showed significant improvement of the basal responses on SSEPs, and 56.8% showed no significant change during the procedure. In 28.4% of the cases, the surgical team had to be advised of potential neurological damage and in 2.4% there was absence of neurophysiological responses. No patient showed complete loss of any neurophysiological response. All patients reported clinical improvement after hospital discharge. CONCLUSIONS: Intraoperative neurophysiological monitoring may help avoid certain neurological risks during spine surgery, which may go unnoticed without the use of this technique.

Emisiones otoacústicas y audiometrìa tonal en niños en tratamiento con citoplastino / otoacustic emissions and tonal audiometry in children under cisplatin treatment

Objetivo: Comparar la validez de las emisiones otoacústicas (EOA) por producto de distorsión (EOAsPD) con la audiometría tonal, en niños que reciben cisplatino. Material y Método: Se revisaron expedientes de 25 sujetos, con edades de 2 años 6 meses a 15 años de edad, de los cuales 14 eran niñas, todos con tratamiento a base de cisplatino. Los estudios de EOA y la audiometría tonal se realizaron el mismo día en cada niño; 3 sujetos participaron con 2 estudios, por lo que el total de parejas de estudios analizados fue de 29. Resultados: Estableciendo el punto de corte en 45 dB HL en la audiometría tonal y diferencia 4 dB-SPL en las emisiones otoacústicas, la especificidad diagnóstica de las EOAsPD es de 0.97 y la sensibilidad es de 0.57. Conclusión: Las EOAsPD son altamente específicas y medianamente sensibles; el procedimiento es rápido, objetivo y no requiere de mucha cooperación del paciente. Esto hace a las EOAsPD un buen medio diagnóstico de tamizaje para identificar la pérdida auditiva en pacientes bajo tratamiento con ototóxicos

Estimulación magnética transcraneal y trauma acústico / Transcranial magnetic stimulation and acoustic trauma

La estimulación magnética transcortical (TCMS) es un método no invasivo para el estudio de la función motora en humanos, sin embargo, existen algunos autores que sugieren que causa daño auditivo (coclear). Se estudiaron 15 pacientes (edades entre 11 meses y 16 años, con una media de 6.8 años) con potenciales evocados auditivos de tallo cerebral (PEATC), emisiones otoacústicas (EOAs), reflejo estapedial (RE) y audiometría convencional cuando fue posible, antes y después de TCMS para estudios de conducción central en enfermedades neurológicas diferentes. Los pacientes no tuvieron protección auditiva ni historia de crisis convulsivas. Los potenciales evocados motores fueron registrados de los músculos abductores breves y primer interóseo dorsal en reposo y durante la contracción voluntaria cuando esto fue posible. Un promedio de 18 estímulos fue aplicado con intensidades entre 50 y 75 por ciento (11.5 Teslas de intensidad). Los PEATC, EOAs, RE y audiometrías fueron practicados antes y después de la estimulación, dos semanas después y dos meses después cuando fue posible. La distribución logarítmica natural tuvo disposición normal. No existieron diferencias significativas en las pruebas de función auditiva. Por tanto, es un procedimiento seguro para la integridad de la vía auditiva.

Enfermedad cerebrovascular: doce años de experiencia en el tratamiento quirúrgico de la obstrucción carotídea / Cerebrovascular disease: a 12 year experience in the surgical treatment of carotid obstruction

Introducción: se consideró prudente revisar el tema y la casuística de doce años por los autores en pacientes con infarto cerebral por enfermedad carotídea, por la elevada morbilidad y mortalidad así como la frecuencia de secuelas incapacitantes.Material y método: presentamos nuestra experiencia en el Hospital ABC de junio de 1988 a junio del 2000, en el tratamiento quirúrgico de la obstrucción carotídea en 63 pacientes (33 Fem. y 30 Masc.), con edad promedio de 70 años, que requirieron 68 endarterectomías. Sus factores de riesgo incluían: hipertensión arterial 40 Ptes., tabaquismo 40, cardiopatía isquémica 22, neumopatía 12 y diabetes m. 10. Fueron 40 endarterectomías izquierdas y 28 derechas; 61 por estenosis sintomática y 7 asintomáticas. Los principales síntomas fueron: ataques de isquemia cerebral transitoria 39, infarto cerebral previo 13 y amaurosis fugax 9. El porcentaje promedio de estenosis en las lesiones sintomáticas fue de 86.47 por ciento y en las asintomáticas de 82 por ciento. Resultados: todos los pacientes fueron operados bajo anestesia general endotraqueal, con protección cerebral farmacológica, monitorización electroencefalográfica y de potenciales evocados somatosensoriales. Nueve casos (13.23 por ciento) requirieron la colocación de una derivación (shunt) transoperatoria. El tiempo promedio de pinzamiento carotídeo fue en los pacientes sin derivación 35.8 minutos y con derivación 4 minutos. Siete casos, todos del sexo femenino, requirieron arteriorrafia con parche; 4 con dacrón, 2 con PTFE y 1 con vena safena. El tiempo promedio de cirugía fue de 2 horas 37 minutos. Mortalidad operatoria 1 caso (1.47 por ciento) por fibrilación ventricular secundaria a infarto agudo del miocardio. Morbilidad neurológica central 1 caso. Morbilidad neurológica periférica 2 casos por lesión neuropráxica del recurrente laríngeo y del facial con recuperación completa. Morbilidad no neurológica 9 casos (13.23 por ciento): HTA postoperatoria 4, hipotensión arterial postoperatoria 3, hematoma 1 e IAM 1.El tiempo promedio de estancia hospitalaria fue de 4.52 días. Discusión: los resultados de esta serie de endarterectomías carotídeas con pacientes cuya edad promedio fue la 8a. década de la vida, con ASA III en 47 por ciento de los casos, donde 89.7 por ciento presentaba estenosis sintomáticas de 86.47 por ciento promedio, muestran baja mortalidad operatoria y morbilidad neurológica central, equiparables a los resultados de los estudios NASCET y ACAS.

Potenciales evocados / Evoked potentials

Los potenciales evocados (P.E.) son la respuesta eléctrica del cerebro ante um estímulo sensorial que puede ser auditivo, visual o eléctrico. Se describe la técnica de promediación y registro y la utilidad clínica de cada una de las modalidades

Diagnóstico electroencefalográfico / Electroencephalographic diagnosis

El electroencefalograma (EEG) es el registro de la actividad elétrica cerebral obtenido por electrodos colocados sobre el cráneo. Se describe la técnica, la actividad electroencefalográfica normal, la actividad anormal, principalmente en el paciente epiléptico haciendo especial hincapié en las crisis generalizadas, focales y del recién nacido. Se menciona los cambios que puede sufrir el EEG en las diferentes fases de la enfermedad y el valor pronóstico del mismo

Potenciales evocados auditivos de latencia tardía / Auditory evoked potentials of late latency

Los potenciales evocados auditivos de latencia tardía aparecen de los 50 mseg. en adelante y parecen representar la activación de la corteza cerebral primaria y secundaria. También se les conoce como endógenos o relacionados con el evento; esto se debe a que aparecen cuando el sujeto pone atención en el estímulo y este último es informativo para el sujeto. Existen numerosos componentes tardíos: P165, N2, P290, P3a, P3b o P300 o P3, Onda lenía y el P4. Estos componentes se encuentran en experimentación. El que más se ha estudiado y en la actualidad ya tiene una aplicación clínica es el P300. Este componente está relacionado con procesos de percepciones y conocimientos, y se altera en sujetos con demencia o desarrollo intelectual bajo

Estudio poligráfico del sueño y sus trastornos / Polygraphic study of the sleep and its disorders

Es evidente que hay gran variedad de síndromes clínicos y la prevalencia de los trastornos del sueño en la población general son muy altos. Los mayores adelantos en el conocimiento de la fisiología normal y patológica del sueño se han realizado desde la primera mitad del siglo XX y esto ha llevado a la creación de grandes centros de investigación y al desarrollo de una tecnología para la obtención de mejores registros. En este artículo se revisarán los elementos básicos de la fisiología normal del sueño y se hará referencia de aquellos síndromes comunes, bien definidos y que requieren de un estudio polisonográfico para su diagnóstico (hipersomnia, síndrome de apnea durante el sueño, narcolepsia, parasomnias, insomnio)