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Biomedical subjects

D Samson-Dollfus

Publications and source records attributed to D Samson-Dollfus.

At least 37 records · Page 2Linked to original sources

[Slow-wave paradoxical sleep during the 1st year of life].

A typical aspect of the EEG during Paradoxical Sleep (PS) was noted in 76% of 68 infants, 3 to 11 months old. This consisted in delta waves of high amplitude recorded during PS. These waves were seen from the beginning to the end of the first year of life; they could occupy all or part of each stage of PS and were seen at any time during the night. Few works have been published by other authors on the same subject. However, Tanguay et al. (1974) have observed that high delta waves in PS were present until four and a half year of age and that the relative delta power in PS decreased slowly between the first and fifth year of life. The problem consisted in finding out whether this type of tracing was related to the immaturity of some brain structures.

Child Development↗

[Gastro-esophageal reflux and nocturnal sleep in the adult: method and results obtained in healthy subjects].

Esophageal pH has been studied at night in six healthy subjects. A pH electrode was placed 5 cm above the low esophageal sphincter and sleep state was monitored. The subjects were connected to the recording devices during two nights, but the recording was performed only during the second night. A pH drop superior to 2 units and lasting longer than 30 sec was estimated as a gastro-esophageal reflux (GER). GER episodes were determined from beginning of sleep to definite waking. Ten GER appeared in four of the six subjects. They occurred both during transient arousals or complete wakefulness, but never in NREM or REM sleep. These results are consistent with those previously reported in normal subjects. On the contrary, GER were reported during REM sleep or NREM sleep in 'near miss' sudden infant death infants and in asthmatic children. Thus, the dysfunction of the esophagus might be considered either as the origin of the diseases, or as one of their consequences.

Adult↗

[Electroretinogram and chronic poisoning by synthetic antimalarials].

Electroretinograms (ERG) obtained before and during chloroquine therapy have been compared. The results showed an increase in the amplitude of A, X and B waves. These results are in contradiction with those of other authors having reported that A and/or B waves decreased in cases of lesions of the retina due to the chloroquine. Such discrepancies may be due to the fact that ERG were recorded at different stages of impregnation of the retina by the chloroquine, and perhaps, because of a specific and early impregnation of the ganglion cells. It seems absolutely necessary to record the ERGs regularly in order to detect when the waves begin to decrease, since this may be the threshold of a real intoxication.

Chloroquine↗

[Topographic aspects of visual evoked potentials recorded after flash-pattern stimulation in normal subjects].

Visual evoked responses have been recorded on 14 leads placed on the scalp. They were localised on the central, parietal, temporal and occipital regions. The common reference was linked-ears. The stimulus consisted of a flash pattern. The size of the pattern and of each square was respectively of 20 degrees and 30 min. The stimulation of the total visual field had evoked two families of curves. One of these types of curves was posterior (occipital, temporal and parietal) and consisted in a positive, negative, positive wave (100, 136, 200 msec on average) and the second type was localised on the central leads and much more rhythmic than the posterior response. The initial complex (negative, positive, negative, positive: 70, 92, 120, 178 msec) was followed by a slow after-discharge. The half-field stimulation evoked a P100 component on the contralateral posterior leads, but this P100 was less prominent on the ipsilateral posterior leads. The modifications were particularly evident at the level of the temporal posterior electrodes. This P100 component was the only wave to be modified by half-field visual stimulation. The posterior N136 and P200 wave and all the rhythmic central response were exactly the same with half or total visual field stimulation. The results have obviously shown that the different waves of the visual evoked responses are not coming from the same sources. The interpretation of multichannel evoked recordings was therefore very difficult.

Adult↗

[Methodology, limitations and value of mapping in electroencephalography].

Data processing is mandatory for EEG mapping. After having used a correct filter and ADC, spectral analysis is completed by interpolating between the spectral values obtained on each recording point to allow a sufficient number of values to be expressed in a grey or color scale on the skull projection plane. The obtention of valid results implies extreme care in data recording and processing. Transitory events (paroxysmal bursts) cannot be detected by spectral analysis. Nevertheless, EEG spectral data mapping is a very good technique to show abnormal EEG focuses in neurology, to study all sorts of neuropsychological reactivities, to follow the evolution of tracings during normal or abnormal aging, metabolic diseases or drug effects.

Aging↗

[Development of a criterion for the automatic detection of sleep spindles in the infant].

The authors present a model for automatic detection of spindles during the different sleep stages. Baseline spindle-free EEG was modelized on a 10 sec recording using an autoregressive model. Spindles were thereafter detected using the quadratic error from this baseline model on successive 1 sec periods. This automatic detection is in a 95.7% agreement with visual analysis.

Computers↗

Positive rolandic sharp waves and periventricular leukomalacia in the newborn.

Four cases of periventricular ischemia without hemorrhage in premature infants are described in which positive rolandic sharp waves (PRSW) were predominant in the electroencephalogram (EEG). These findings suggest the relationship of PRSW to periventricular ischemia rather than to intraventricular hemorrhage, per se, as has been considered by most investigations in the past. These PRSW can provide an early indication of periventricular leukomalacia.

Electroencephalography↗

The value of serum IgE assay in milk aspiration and the sudden infant death syndrome.

Global serum levels of IgE (PRIST, Phadebas) and specific anti-cow's milk IgE (RAST) were measured in populations of infants with a history of one or more episodes of milk aspiration (n = 12), victims of the sudden infant death syndrome (SIDS) (n = 18), "near miss" SIDS infants (n = 23), siblings of a SIDS victim ((n = 21) and control infants (n = 38). Only the infants with a past history of milk aspiration had significantly raised global and specific IgE. The absence of raised specific IgE in the subjects who died from SIDS argues against the hypothesis of sensitisation to cow's milk proteins during a previous episode of aspiration. Nasopharyngeal reflux is frequently seen in near-miss infants. This reflux is more often responsible for reflex apnoea due to stimulation of the laryngeal chemo-receptors than to a fatal aspiration.

Animals↗

Sudden infant death syndrome in a twin: a comparison of sibling histories.

To determine possible characteristics of infant victims of sudden death, we examined 114 items related to the pre- and postnatal histories of 42 pairs of twins one of whom died of sudden infant death syndrome (SIDS) leaving a surviving sibling. Interviews with the parents were conducted after the occurrence of SIDS, and the data were checked with records held by gynecologists and pediatricians. To evaluate the specificity of any factors, we studied a control group of 42 age- and sex-matched pairs of twins, both of whom survived the first year of life. Only 11 of 114 characteristics were significantly related to SIDS: future victims had a smaller weight and height at birth, stayed longer in the nursery, and followed a moving object with their eyes, had head control, and smiled at a later age than their surviving siblings. They also fatigued more often during feeding (11/42) and had reduced arm and neck tonus (9/42). They were described as longer sleepers than their surviving siblings. During sleep, some SIDS twins, but no surviving twin, were found to be cyanotic at least once or pale (4/42) and were repeatedly covered with abundant sweat (8/42). In the control group of normal twins, the occurrence of most of these characteristics was found with a frequency comparable to that seen in the SIDS infants; the specificity of these characteristics is thus considered doubtful. The mean birth weight and height were significantly greater in the control group, and no control infant had an episode of cyanosis or pallor or repeated episodes of profuse sweating observed during their sleep.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Height↗

[Flash-pattern visual evoked potentials and limited lesions of the occipital lobe].

Four patients with restricted lobe lesions and one patient with large occipital lesions were selected for VEP studies to full-field and half-field flash pattern stimuli. The abnormalities of the responses were more important with full-field stimuli. In three patients with inner side occipital lobe damage, the P100 component disappeared ipsilaterally to the lesion, but N140 remained normal on bilateral occipital leads. In one patient with outer side occipital lobe damage, P100 was normal on bilateral occipital leads, but N140 disappeared ipsilaterally to the lesion. In one patient with large occipital lesion, P100 and N140 both disappeared ipsilaterally to the lesion. It appears that the P100 component is related to the inner and that N140 is related to the outer area of the occipital lobe.

Adult↗

[EEG recorded during the 1st 48 hours after a cerebral vascular accident as a result of carotid stenosis].

This article describes the principal EEG abnormalities noted during the first 48 hours of cerebro-vascular ischemic accidents due to carotid artery obstruction. No instances of slow delta waves were seen in the 60 cases of transient ischemic accident. In the 162 cases of cerebro-vascular accidents, all EEG abnormalities were correlated with the level of consciousness and thus add little to the clinical data with respect to the prediction of short-term mortality. However, in the 135 patients who presented a cerebro-vascular accident with no alterations of consciousness, the appearance of polymorphic delta waves or spikes (focalized or diffuse) within the first 48 h does significantly predict short-term mortality.

Brain Ischemia↗

Analysis of background activity.

Analysis of EEG background activity in epilepsy has been much less used than automatic detection of paroxysmal figures. However, it would be useful to study the background activity with precision. The techniques used can belong to the time domain or the frequency domain. They make it possible to study the variations of EEG background activity as a function of the drug therapy and the type of epilepsy; some prognostic indices can then be derived for different kinds of epilepsy. It seems probable that topographic displays of background frequency bands will be very interesting in the near future. Finally, automatic analysis of sleep recordings in epileptic patients also makes it possible to test drug effects and modifications of sleep stages, as a function of the type of epilepsy.

Action Potentials↗

A critical comparison of the history of sudden-death infants and infants hospitalised for near-miss for SIDS.

To determine whether significant historical differences distinguish the near-miss for Sudden Infant Death from the infants who died of SIDS, we analysed the histories and clinical data from two groups of infants seen in our University Hospital and from collaborative research group. The data were obtained with the use of a standardised questionnaire and consultation of all available medical data. Sixty-five infants were identified as near-miss for SIDS after they had suffered a severe cardiorespiratory incident during sleep for which no cause could be found despite a complete medical examination. After an autopsy had failed to reveal a cause for the unexpected death 95 cases of SIDS were retained in the study. A series of 353 variables were collected from the parents, the gynaecologists, neonatologists and attending physicians. After statistical analysis, only 15 of the 353 items studied significantly differentiated between the two groups. A step-wise discriminant analysis performed on these items led to the identification of six independent variables: the time of the incident; the circumstances leading to the observation of the child; the child's sleep position; previous minor intestinal problems; the size of the family and the mother's coffee consumption. Most variables indicate that the near-miss infants were discovered and rescued earlier than the infants who died. No other historical information appeared significantly to differentiate between the two groups of infants. These data need confirmation from a prospective epidemiological survey.

Family Characteristics↗

Electroencephalograms in basilar artery migraine.

Nine cases of 'basilar artery migraine' (BAM) have been recorded. In 8 cases, excess of beta activity was observed during the attacks and disappeared in less than 3 days. The inter-ictal EEGs were normal. Drug ingestion was excluded each time. These EEG patterns are different from those which have been reported in the literature, i.e., transitory posterior abnormal slow waves. However, case no.1 is in agreement with the literature. The expression 'BAM' probably covers different syndromes which are further discussed.

Adolescent↗

[Dissociation of visual evoked responses to hemi-field or full-field flash-checkerboard stimulation].

Unexpected visual evoked responses (VERs) were recorded in 5 subjects with tumoral, ischemic or hemorrhagic lesions of the retrochiasmatic visual pathways. The flash pattern stimulation was always binocular and involved full-field and half-field stimuli. In these 5 cases, the total field VER was asymmetrical with anomalies on the affected occipital region. However half-field VERs P100 contralateral to the stimulus were noted both on the normal and on the affected occipital region. One can ask if this is not an electrophysiological equivalent of the clinical relative hemianopsia.

Adult↗

Sudden unexpected infant death in a French county.

We report a study of sudden unexpected infant death (SUID) in a French county (Seine-Maritime) between 1978 and 1981 (rate of 2.71 per 1000 live births). The results agree with those of previous studies concerning sex ratio, seasonal variation, and peak age of death. No relation between gestational age and age of death was found. A comparison with matched living control infants was performed for 136 of the 207 total deaths for whom computerised medical data were available. Significant differences were found between these two groups in gestational age, birthweight, admission to a paediatric ward at birth, and proportion of single mothers. In analysing birthweight and gestational age separately, the birthweights of SUID cases were significantly lower than those of controls, whatever the gestational age. The converse was not true, however: in classifying infants by birthweight, a significant difference between the gestation period of SUID victims and controls was found only for low birthweight infants (less than 2500 g). It is considered that it may be possible to identify infants at particular risk of SUID within the group of babies admitted to hospital at birth for major problems, and a study is currently underway among infants born in Seine-Maritime in 1982.

Age Factors↗