[Visual evoked potentials and electroretinogram in pediatrics. Concept methodology and clinical applications]. / Los potenciales evocados visuales y el electrorretinograma en Pediatría. Concepto, metodología y aplicaciones clínicas.

INTRODUCTION: Since the first visual evoked potentials were obtained in the early 1940s, many important technical advances have been developed helping to produce more correct responses. One of the most important has been the incorporation of computers in the 1960s. This allowed the improvement in the relation signal/noise and consequently the responses are much more reliables technically. Also the improvement in the stimulators and electrodes necessaries for this test. However, all this advances introduced the use of the physical and technical concepts and magnitudes that sometimes fall outside the strict field of the medicine. MATERIAL AND METHODS: Therefore we have divided this work into three very different parts. The first part is dedicated to remembering and defining a series of physical concepts and their usefulness in the obtention of VEPs and ERGs specially in the physical process witch the proper use are basic to attain correct responses. In the second part we will discuss VEPs and ERGs in pediatric patients under the age of two years., concentrating basically on the every day specific problems witch appear on treating young patients. Finally we will review briefly their most frequent clinical applications.

Predictive value of brain-stem auditory evoked potentials in children with post-traumatic coma produced by diffuse brain injury.

In the present study, brain-stem auditory evoked potentials (BAEPs) in 31 children in post-traumatic coma with diffuse brain injury were examined. The BAEPs were recorded in the first 72 h after hospital admission and the findings of 29 patients related to the level of neurological recovery at 6 months after head injury. On the basis of the results, children were divided into three groups: the first consisted of children with bilateral and normal BAEPs (n = 19); the second of those with asymmetrical BAEPs (n = 6); and the third of those in whom BAEPs has disappeared or in whom only responses of the seventh cranial nerve and cochlear nucleus were recorded (n = 4). All the patients in the first group presented a good clinical outcome, with excellent recovery in 80%. In the second group three children (42.8%) had a good recovery, two (28.6%) were moderately disabled and one (14.3%) died of extraneurological causes. All the patients in the third group died. Abnormal BAEPs showed a significant correlation with absence of pupillary and/or corneal reflex, but not with the Glasgow Coma Score and anisocoria. Good statistical correlation was observed between normal BAEPs and visualization of basal cisterns on computed tomographic scan. The incidence of increased intracranial pressure was higher in patients with abnormal BAEPs, but the differences were not significant (P = 0.06). Our study confirms the predictive value of BAEPs in children's post-traumatic coma due to diffuse brain injury.

[Chronic encephalopathy in patients with sex-linked agammaglobulinemia]. / Encefalopatía crónica en pacientes con agamaglobulinemia ligada al sexo.

The clinical and neuroradiological findings of two patients with X-linked agammaglobulinemia, who developed a chronic encephalopathy, are presented. The main neurological manifestations in both patients were: progressive spastic tetraparesis, cortico-subcortical type of dementia and seizures. No infectious agent was identified in either patient. A systematic review of the clinical findings of 37 patients reported in the literature with X-linked agammaglobulinemia and chronic encephalopathy allows the distinction of two subgroups of patients according to their form of presentation (acute or insidious). In each subgroup there are significant clinical differences. The clinical-neuroradiological similarities between this complication and the ones derived from the vertically transmitted form of the human immunodeficiency virus are pointed out. Finally, emphasis is made on the need for CSF viral cultures on patients with X-linked agammaglobulinemia as soon as a neurological complication is suspected.

[Walker-Warburg syndrome: cerebro-ocular dysgenesis and congenital muscular dystrophy]. / Síndrome de Walker-Warburg: disgenesia cerebro-ocular y distrofia muscular congénita.

We report the case of an infant with facial dysmorphism, congenital hydrocephalus, severe hypotonia and absence of psychomotor development, with ocular and cerebral malformations consistent with the diagnosis of Walker-Warburg syndrome (WWS). Investigations included a cerebral CT scan indicative of type II lissencephaly and a muscular biopsy which showed findings of muscular dystrophy. The association of hypotonia, developmental delay and seizures with a neuronal migration disturbance and retinal involvement raised the suspicion of a peroxisomal disorder. The pertinent biochemical investigations, however, were negative. The features of this syndrome are reviewed, emphasizing the similarities with other related disorders as cerebro-oculo-muscular syndrome. We suggest that muscle involvement should be investigated in every case of WWS.