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E J Colon

Publications and source records attributed to E J Colon.

At least 37 records · Page 2Linked to original sources
PubMed1987

The maturation of the central auditory conduction in preterm infants until three months post term. I. Composite group averages of brainstem (ABR) and middle latency (MLR) auditory evoked responses.

Brainstem (ABR) and middle latency (MLR) auditory evoked responses were obtained sequentially in 49 preterm infants until three months post term date. In addition, the records of 16 preterm infants, obtained at different conceptional age levels, were included. The recording of these responses was performed successively in one procedure, together with auditory cortical evoked responses. The infants were divided into 5 groups according to their gestational age, i.e. the term at birth. Composite group averages were determined, showing the group stable components of the 5 gestational age groups at 8 different conceptional age levels, i.e. term at the time of the recording. The intra group stable components could thus be determined for further study of developmental trends in the responses. The group averages also serve as a reference in the visual analysis of the individual records. The averaged ABRs showed that with increasing conceptional age increasingly better identifiable waveforms were obtained. These were particularly outstanding for peaks I and V ipsilateral to stimulation, and peaks IIc and Vc contralateral to stimulation. This enabled the measurement of the central conduction times. The MLRs were especially remarkable for their latency changes which occurred in peak PO and the troughs Na and Nb. The results indicated that the conduction of the subcortical auditory afferent signals can be measured successfully in groups of very premature infants with ABRs and MLRs.

Audiometry, Evoked Response↗
PubMed1987

The maturation of the central auditory conduction in preterm infants until three months post term. II. The auditory brainstem responses (ABRs).

Auditory evoked brainstem responses (ABRs) were recorded in 65 preterm infants (serially in 55 of them), divided into 5 groups, according to their gestational age (GA). The recording sessions were performed at 8 conceptional age levels (CA = GA + chronological age), of which the last two were about 40 and 52 weeks CA. The number of recording sessions varied from one to seven. A full set of ABR latency and amplitude parameters was analyzed including peaks I, II, IIN, III, V and IIc, IIINc and Vc as well as some interpeak latency differences (IPLDs), and the amplitude ratios. The detectability of the different components in the ABR tests at 70 dB reached 80-100% at about 32 weeks CA. The side of stimulation nor the state of vigilance influences the detectability. The degree of prematurity in the 5 GA groups did not influence the development of the parameters. Neither the side of stimulation nor generally the state of vigilance give rise to different parameter values. The thresholds show an age dependent decrease, which is also determined by central maturation. The differential development of the latency decrease of the ABR parameters with increasing conceptional age can be associated with morphological maturational processes and may add weight to the arguments in the delineation of the sources of the ABR. The ipsi- and contralateral central conduction V-II and Vc-IIc do not show latency differences at any CA level. The components IIc and Vc, however, lagged behind in absolute latency compared with II and V. It is concluded that the ABR is a powerful instrument for the study of the maturation of the human auditory pathway in the brainstem. In view of the variability, the detectability and the complex changes within the ABR during the preterm period, its application for clinical purposes during this period has a limited value.

Analysis of Variance↗
PubMed1987

The contribution of evoked potentials to the diagnosis of demyelinating diseases.

Examination of evoked potentials can be a useful diagnostic tool in the diagnosis and evaluation of patients with Multiple Sclerosis (MS). A description of the most frequently used EPs is given: BAEP, checkerboard VEP and short latency median nerve SSEP, together with an impression of their sensitivity. It is obvious that more clinical trials are necessary to evaluate also the other EP modalities before a balanced conclusion about the usefulness of EPs in MS can be formulated.

Demyelinating Diseases↗
PubMed1986

Some comments on the clinical use of evoked potentials.

In this survey we describe the uses of somatosensory, visual, and auditory evoked potentials (EPs), adding some critical comments on the values and pitfalls of these methods. It must be stressed that the application of EPs is most valuable when combined with a thorough neurological examination. There is general agreement that EP measurement is one of the best techniques for objective, noninvasive study of brain function in humans.

Brain↗
PubMed1986

Neurophysiological studies in the Leigh syndrome.

We performed neurophysiological studies in 12 patients with the Leigh syndrome (6 pathologically confirmed and 6 clinically diagnosed). The results are compared with data derived from a literature survey of 173 Leigh syndrome patients. We found no positive contribution of neurophysiological studies towards the diagnosis of the Leigh syndrome.

Brain Diseases, Metabolic↗
PubMed1986

Long-latency somatosensory evoked potentials.

Theoretically, long-latency somatosensory evoked potentials (SEPs) provide information on the function of somatosensory associative cortical structures. Their potential role in clinical studies and research has been hampered by the lack of standardized methodology in the use of these SEPs. Other factors, such as drugs, simultaneous stimuli, and state of consciousness, also have far-reaching influences on the various parameters of long-latency SEPs. The knowledge of the origin of most SEP components is at best fragmentary; studies on clinical-electrophysiological correlations seem to be hopeful in this respect. As yet, clinical applications of long-latency SEPs are limited; for future research, studies of disturbances of SEPs are most promising, mainly with regard to diseases of the gray matter, the influence of drugs on the cerebral function, and psychopathology.

Adolescent↗
PubMed1986

The central auditory conduction at term date and three months after birth. II. Auditory brainstem response.

This communication describes the results of auditory brainstem responses (ABRs) obtained in 25 healthy mature newborns with a follow-up at 3 months of age. The combination of ipsi- and contralateral recordings, the intensity series and the comparison with the composite group averages are useful for the identification of the separate ABR components. Differences between the records after right or left ear stimulation were not observed. Comparing our data with those obtained by others, we conclude that the interpeak latency differences (IPLDs) offer a more consistent measure of ABR latency values than the peak latencies measured from stimulus onset. The simultaneously recorded ABRs ipsi- and contralateral to stimulation show both at term, and at 3 months, an equal central conduction time. The ABR II-V complex shows contralaterally a significant shift compared with the ipsilateral II-V complex. The significant latency changes observed between term and at 3 months are due mainly to the latency decrease in the II-III IPLD.

Age Factors↗
PubMed1986

The central auditory conduction at term date and three months after birth. III. Middle latency responses (MLRs).

Middle latency responses (MLRs) were obtained in 25 healthy newborns with a follow-up recording at 3 months in all but three. A four-channel recording provided topographic information. Linkage of the ear references reduced the myogenic contamination of the recordings. P0 and Na proved to be the most consistent components in the sinusoidal MLR wave sequence. Topographic differences suggest a generation of P0 and Na contralateral to stimulation. A significant latency decrease was found for P0 and na between term and 3 months. The most important latency and amplitude changes may occur before term date and immediately thereafter. The MLRs are the link between the auditory brainstem responses (ABRs) and the auditory cortical responses (ACRs), and it may be possible to use them for recordings in newborn infants. They provide information about the generation of specific components as well as regarding the auditory afference in the stimulus propagation between the brainstem and the cortical auditory areas.

Auditory Cortex↗
PubMed1986

The central auditory conduction at term date and three months after birth. IV. Auditory cortical responses.

Auditory cortical responses (ACRs) were recorded in 25 healthy mature newborns with a follow-up at 3 months. The waveform, latencies and amplitudes for the ACRs for this time period are studied. Topographic differences between the central and central-temporal derivations and changes between term and 3 months are found with respect to latencies and amplitudes for different peaks and troughs. The ACRs, obtained as a part of a protocol covering the entire auditory afference, offer consistent parameters, which can be used to study developmental neurophysiological properties of audition and which are potential diagnostic tools for the detection of deviant sensory or mental development.

Auditory Cortex↗
PubMed1985

The application of evoked potentials in the diagnosis and follow-up of children with intracranial tumors.

Somatosensory and brainstem auditory evoked potentials (SSEPs and BAEPs) provide sensitive measures of the central conduction functions of the auditory and somatosensory input systems at different levels of the central nervous system. The contribution of SSEPs and BAEPs in the primary diagnosis and follow-up of 26 children with infra- and supratentorial tumors were reviewed. The SSEPs, especially the specific complex, showed a latency increase in patients with supratentorial and brainstem mass lesions involving directly or distantly the somatosensory tracts. The BAEPs were sensitive for supratentorial pressure effects and for local and distant posterior fossa tumor effects. In the follow-up of children, evoked potentials offer a good method of detecting tumor recurrence, whereas neuroradiological procedures may be obscured by surgical or radiation artifacts.

Adolescent↗
PubMed1985

Preliminary note: vertebral-Doppler sonography in near sudden infant death syndrome (NSIDS).

Using vertebral artery sonography, we investigated the influence of the position of the head on the vertebral artery bloodflow in five children, who were admitted because of NSIDS (near sudden infant death syndrome) episodes. Three out of the five children showed blocking of vertebral bloodflow determined by position of the head. This was not observed in five age-matched controls. Our preliminary observations indicate the value of noninvasive ultrasound Doppler techniques in the diagnostic work in the children with NSIDS. In this way one of the risk factors for SIDS might be identified.

Arterial Occlusive Diseases↗
PubMed1985

Benign (nonparoxysmal) familial chorea of early onset: an electroneurophysiological examination of two families.

A nonparoxysmal nonprogressive autosomal dominant choreatic disorder of early onset is described in two families. Laboratory investigations of blood, urine and cerebrospinal fluid were normal. Extensive electroneurophysiological examinations did not reveal evident abnormalities. The contingent negative variation was also normal, except for a P500. These electroneurophysiological data are the opposite of what can be found in cases of Huntington's chorea.

Child↗
PubMed1985

Chronotopographical potential distribution of some SSEP components in cerebrovascular insufficiency.

In 7 patients with symptoms of cerebrovascular diseases a somatosensory evoked potential (SSEP) chronotopogram was constructed after median nerve stimulation of seven different EP components: N20, P25, P45, P100, N140, P200 and P300. We examined only a limited number of patients (and controls) because the methodology is very time-consuming. We analyzed the topography in these patients in order to obtain insight in the effect of this disease on EP distributions and to find arguments in favor of the use of this methodology in clinical examination. These chronotopographical maps were constructed on the basis of the localization of maximal amplitude of the different components and their dipole counterparts (if present). 3 patients showed a delay of the specific components, and in 1 patient most of the non-specific components were delayed. The chronotopographical representation in most patients was abnormal. Relations with clinical state and computer tomography (CT) are described. Focal hypodensity on the CT gives rise to a large extension of the area of the specific component N20, overruling the dipole counterpart P20. Slight cortical atrophy in 4 patients causes abnormalities in the P300/N300 dipole direction. Chronotopograms give new information. Therefore, it seems justified to improve the method and implement it for clinical use in the near future.

Adult↗
PubMed1985

The central auditory conduction at term date and three months after birth. I. Composite group averages of brainstem (ABR), middle latency (MLR) and auditory cortical responses (ACR).

We are investigating the maturation of auditory evoked responses, as a potential diagnostic tool for the neurological examination of premature infants at the Intensive Care Unit for Prematures. In this communication we report the group composite averages of the BMC-ARs in a group of 25 mature and healthy newborns with a follow-up at 3 months of age. The ABRs showed a remarkable variability in wave I latency, with a relatively stable I-V central conduction time (CCT) of the brainstem. The ipsilateral II-V CCT does not differ appreciably from the contralateral II-V CCT. The MLR components NoPoNa and Nb, Nc, Nd are easy to identify in the group averages. Voltage asymmetry between stimulated versus non-stimulated side is slight but persistent in the newborn period as well as at 3 months of age. The group averaged ACRs, show an early complex within the latency reach of 100 ms and a slow W-shaped late complex, most distinct at 3 months. The results indicate that the protocol as applied constitutes a tool for the testing of conduction function of the auditory afference in newborns, even beyond the level of the brainstem. Group averaging offers a method to determine the intragroup stability of evoked potentials under investigation.

Acoustic Stimulation↗
PubMed1984

SSEP chronotopography in patients with multiple sclerosis.

In 10 patients with definite MS, an SSEP chronotopogram was constructed of 7 different, well-defined components: N20, P25, P45, P100, N140, P200 and P300. Chronotopographical maps were constructed on the basis of the localization of maximal amplitudes of the different components and their dipolar counterparts (when present). Most patients showed a delay of different specific as well as aspecific components. The chronotopogram was not much different from normal except for P45. Most generators therefore seem to stay stable. One of the P45 dipole generators vanished, probably due to a slight change in its direction, or more probably as a consequence of loss of association fibres in the cortical white matter. Spatio-temporal mapping provides new, clinically relevant information. The development of automatic methods for this mapping is justified for routine clinical use in neurology.

Adult↗
PubMed1982

Recessively inherited 'pure' spastic paraplegia: case study.

Two brothers with 'pure' spastic paraplegia are presented. Inheritance of their condition probably was autosomal recessive. Clinical onset was in the first decade. Peripheral nerve conduction, visual and brain stem auditory evoked potentials were normal. Somatosensory evoked potentials suggested involvement of the cuneate tract. The relevance of neurophysiological evaluation in familial spastic paraplegia is discussed.

Adolescent↗
PubMed1981

The preselection value of the Doppler LP test for shunt-therapy in patients with normal pressure hydrocephalus.

The results of this study confirm the hypothesis that the simple innocuous Doppler LP test may be useful in obtaining information about CSFP-CBF (cerebrospinal fluid pressure-cerebral blood flow) relationships. The value of this test in predicting the clinical outcome of CSF shunting in patients with normal pressure hydrocephalus (NPH) was studied. Fourteen patients with NPH were examined; eight patients showed a positive and six patients a negative Doppler LP test. Seven of the eight patients with a positive test improved following the shunting procedure, but none of the six patients improved after operation. This study suggests that the Doppler LP test is a useful preoperative selection test in patients with NPH. In addition this study supports the hypothesis that CBF autoregulation may be impaired with NPH.

Adolescent↗