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Biomedical subjects

P Salzarulo

Publications and source records attributed to P Salzarulo.

At least 19 recordsLinked to original sources
PubMed1992

Post-natal development of sleep organization in man: speculations on the emergence of the 'S process'.

We outline the development during the first year of life of both sleep-wake patterns and internal sleep organization (sleep states, quiet sleep-paradoxical sleep cycles, and slow-wave sleep), and raise the issue of the emergence of the 'S process'. The consolidation of sleep in episodes of longer duration takes place during the night; the ability to maintain sleep after sleep onset decreases during the day in infants older than 6 months. The main contribution to the increase of longest nocturnal sleep episode duration comes from the quiet sleep, the number of quiet sleep-paradoxical sleep cycles being of minor importance. The temporal analysis of infant sleep structure showed a difference between the first and the following cycles, not only for slow wave activity in infants older than five months, but also for younger infants and for other individual physiological activities (EEG activity, respiratory and cardiac rates): is the early development of these peculiar features a sketch of the 'S Process' described in the adult?

Child Development↗
PubMed1992

Recall of mental sleep experience with or without prior verbalization.

We investigated whether verbalization of contents of mental sleep experience (MSE), just after awakening provoked during rapid eye movement (REM) sleep, facilitates subsequent recall in the morning. Twelve subjects were awakened four times in each of two experimental nights and alternately asked to recall, with or without concurrent verbalization, MSE contents preceding the awakening. In the morning, the subjects were asked to report MSEs both verbalized and nonverbalized during the night. If subjects were unable to provide a spontaneous morning report, they were prompted using a probe, which was the title given by the subjects to each MSE at the end of its verbalization or covert recall at night. Frequencies of spontaneous reports were high, regardless of whether MSEs had been previously verbalized or not. The proportions of spontaneous and probed reports were similar for verbalized and nonverbalized MSEs, but spontaneous morning reports were longer than probed ones, regardless of their previous verbalization. Spontaneous and probed morning reports corresponding to night reports shared similar linguistic structures (i.e., length of sentences and proportions of waking-related utterances, which are indicative of difficulty of retrieval for MSE contents) and had similar percentages of contents common to night and morning reports. These findings support the hypothesis that verbalization does not directly influence the further accessibility of MSE contents.

Adult↗
PubMed1991

Oxygen consumption during sleep in children under continuous and cyclic nutrition.

The present study investigated the effects of two modalities of parenteral nutrition (continuous nutrition over the 24-hour period vs. cyclic nutrition, i.e., administered only during the night) on O2 consumption during sleep in children affected by severe gastrointestinal diseases. In both feeding modalities O2 consumption was always highest in REM sleep, intermediate in stage 2 and lowest in SWS. The trends during the night of O2 consumption (an increase from the second to the third part of the night) for different sleep stages were comparable in both feeding modalities. These results suggest that O2 consumption is not affected by the feeding modalities investigated, but is dependent on both sleep stages and time of night.

Cerebral Cortex↗
PubMed1991

The distribution of slow-wave sleep across the night: a comparison for infants, children, and adults.

This study describes the temporal distribution of slow-wave sleep (SWS) (defined as the visually scored stages 3 + 4) across the night for 16 infants aged between 20 weeks and 1 year, 17 children between 1 and 6 years, and 17 adults between 20 and 36 years. In all three groups the amounts of SWS peaked during the first nonrapid eye movement (NREM) episode. SWS decreased across the night for adults and children, but not for infants. In infants the amounts of SWS remained at a fairly constant level from the second cycle onward, although many cycles were observed with zero SWS. The latter was evident from the very low tendency for SWS to appear in consecutive NREM/REM cycles. Rather, SWS was observed in alternate cycles. In children this phenomenon was less prominent but still well visible, and the tendency for SWS to appear in consecutive cycles had increased. In adults SWS occurred predominantly in consecutive cycles. The results suggest that whereas REM recurrence time increases twofold from infancy to adulthood, SWS recurrence time remains of similar length in infants, children, and adults.

Adult↗
PubMed1990

Developmental changes in the clustering pattern of sleep rapid eye movement activity during the first year of life: a Markov-process approach.

Findings are presented in support of the hypothesis that the tendency of sleep rapid eye movement (REM) activity to group into burst structures changes with age during the first year of life in normal infants. Specifically, by assuming a markovian model for the generation of 1 sec long units of REM activity, it is shown that the propensity of those units to develop a sustained clustering pattern may increase during the first 2 months, possibly reaching a plateau at about 4 months. On the other hand, the overall density of REM activity units may continue to increase beyond that point in time.

Age Factors↗
PubMed1989

Effect of early human malnutrition on waking and sleep organization.

In order to evaluate the effect of early human malnutrition (EHM) on waking and sleep organization, a group of 12 infants malnourished (M) from birth were investigated in their first year of life through 24-h polygraphic recordings. The same infants were recorded again after nutritional rehabilitation (R). A group of 12 age-paired normal infants served as controls (C). Both young (less than 4 months) and older (greater than or equal to 4 months) M infants showed a distribution of classes of waking duration different from that of C while the trend with age of the longest sustained waking (LSW) is similar in M and in C infants. The durations distribution of sleep episodes does not differ between M and C infants, while the longest sustained sleep (LSS) is significantly shorter in M than in C infants. The LSW is less clearly located in the day-time and the LSS is less clearly located in the night-time in M infants as compared to C infants. The quiet sleep-paradoxical sleep cycles are significantly shorter in older M infants because of the reduction of quiet sleep. Nutritional rehabilitation tends to improve waking and sleep organization.

Child, Preschool↗
PubMed1989

Decrease of slow-wave sleep in children with prolonged absence of essential lipids intake.

Sleep measures of eight children fed by total parenteral nutrition (TPN) without essential lipids were compared to those of seven children fed by TPN receiving a daily supplementation of essential lipids. Slow wave sleep (SWS) is significantly decreased in the former group, particularly in the second half of the night, thus suggesting that lipids could be involved in sleep regulation.

Adolescent↗
PubMed1989

Interserial and intraserial interference processes in morning recall of mental sleep experience.

This study investigated ways in which predictions from interference theory might explain partial or total failure in the morning recall of mental sleep experience (MSE) episodes reported after provoked night awakening. Interference could take place either between the contents of one MSE episode (intraserial interference) or between the contents of different MSE episodes (interserial interference) and would be more likely to affect morning recall where similar (i.e., interrelated) contents in MSEs are involved. If interference were mainly intraserial, in the morning there would be no change in the difficulty of retrieving interrelated contents, whereas, if it were mainly interserial, there would be increased difficulty in the retrieval of such contents. All the possible pairs of reports obtained by awakening 8 subjects four times in REM sleep during each of four experimental nights spaced at weekly intervals were scored for interrelated contents, using Clark's (1970) system of analysis of paired units, which operates by matching linguistic features. Results showed that interrelations in morning report pairs are as frequent as in night report pairs, maintaining the same linguistic characteristics and with little transfer of contents from one MSE to another. Overall these findings are compatible with the hypothesis that interference is primarily intraserial rather than interserial. It is consequently suggested that morning recall failure may be due to temporary blocking of retrieval.

Adult↗
PubMed1988

Time course of night sleep EEG in the first year of life: a description based on automatic analysis.

The aim of this study is to describe the time course of night sleep in the first year of life. Forty-eight infants aged between 1 and 54 weeks were polygraphically recorded for 1 night. The central occipital EEG derivation was processed with a lab computer in order to obtain every 30 sec an EEG parameter value. The parameter is based on the joint frequency-amplitude distribution of the EEG and displays fluctuations between 2 extreme levels, high voltage low frequency (HVLF) and low voltage high frequency (LVHF). The range of the fluctuations between HVLF and LVHF increases from the period of 1-6 weeks to the period of 7-14 weeks. A further increase of the parameter range occurs after 24 weeks, which remains restricted to the first half of the night. The recurrence time of LVHF and HVLF episodes (possibly corresponding to quiet sleep paradoxical sleep cycles) is about 56 min and does not change with age in the first year of life.

Brain↗
PubMed1988

24-hour behavioural states distribution in continuously fed infants.

This study compared the 24-h sleep states distribution in infants fed orally with separate meals with that in infants continuously fed from birth. Sleep was polygraphically recorded for 24 h in 12 infants (aged between 6 weeks and 14 months) continuously fed since birth through an intracaval catheter, and in 12 age-paired control infants. The amount of sleep states in each six 4-h epoch of the 24-h day was evaluated. A clear decrease of the sleep amount, concerning both Paradoxical Sleep and Quiet Sleep, was observed during the day-time in infants older than 4 months, independently from the feeding condition. This result does not support the role of feeding rhythm upon the early development of sleep pattern circadian distribution.

Circadian Rhythm↗
PubMed1987

The thematic continuity of mental sleep experience in the same night.

It has been found that the contents of mental sleep experience (MSE) in rapid eye movement (REM) sleep are often interrelated. The aim of this study was to see whether this interrelatedness is better accounted for by the hypothesis that the mental sleep experience interrupted by provoked awakening is resumed when the subject returns to sleep (resumption), or by the hypothesis that the same contents are elaborated repeatedly throughout the night (iterative processing). We also aimed to gain some information as to the processes by which contents previously stored in memory are retrieved and inserted into the current MSE. Ten subjects were awakened 4 times on each of 4 nights after 9 min of REM sleep, and the contents of all the possible pairings of reports were scored and compared with respect to the factors "night" (same/different), "report continguity" (contiguous/noncontinguous reports), "unit interrelated" (lexical/propositional), and "interrelationship" (paradigmatic/syntagmatic). Both the occurrences and the frequencies of interrelations were greater for same night pairs than for different night pairs, but without significant differences between contiguous and noncontiguous pairs: these data provide support for the iterative processing hypothesis. The units interrelated in pairs of reports are more frequently at a lexical than a propositional level and show more paradigmatic than syntagmatic interrelationships: these data suggest that the reelaboration of contents of previous MSEs occurs mainly at a local level, making for the coherence, rather than the thematic, progression of the MSE narrative.

Adult↗
PubMed1985

Spontaneous awakening from sleep in infants.

Spontaneous awakenings from sleep were studied in a group of 20 infants whose sleep-waking patterns were recorded polygraphically for 24 h. While 10 infants were orally fed the other 10 underwent continuous feeding for various gastrointestinal diseases. Spontaneous awakening from sleep was analysed with regard to the prior sleep state, age and feeding condition. Infants awoke preferentially out of REM sleep and less often out of non-REM sleep. The feeding condition had no significant influence on the distribution of awakenings. The propensity for REM awakenings was significantly greater than would have been expected according to the REM sleep amount. This tendency was more pronounced for younger (less than or equal to 3 months) than for older (greater than or equal to 4 months) infants. REM sleep episodes which were interrupted by awakenings were significantly shorter than uninterrupted ones, since awakenings occurred predominantly shortly after REM sleep onset. It is proposed that the specific pattern of brain activity during REM sleep facilitates the transition from sleep into the waking state, particularly in the youngest infants.

Brain↗
PubMed1985

Spontaneous non-nutritive sucking in continuously fed infants.

In order to investigate the effects of a deprivation of the nutritive sucking (NS) on the activity of non-nutritive sucking (NNS), we examined 8 infants (ages 1-13 months) continuously fed by intracaval catheter. They had no NS experience at all from birth. Eight age-matched normally fed infants served as controls. The infants were examined for a full 24-h period by polygraphic recordings and behavioural observation. The amount of NNS was computed for the whole 24-h period and separately for each behavioural state (waking, quiet sleep, paradoxical sleep and ambiguous sleep). All the continuously fed infants showed a typical pattern of NNS. There were no differences in amount of NNS between continuously fed and control infants in any behavioural state. These results suggest that NS does not contribute to the long term maintenance of the NNS activity.

Child Behavior↗
PubMed1985

Long term continuously fed infants do not develop heart rate circadian rhythm.

Heart rate (HR) was studied separately for three behavioral states (waking, paradoxical sleep, quiet sleep) at four periods of the nycthemeron, in 8 infants continuously fed from birth. Continuously fed infants show no significant differences for each of the three behavioural states between the HR values of the four periods of the nycthemeron, while controls show a clear decrease during the night-time. Differences between term behavioral states exist both in continuously fed infants and in controls. Long term continuous nutrition does not allow for the establishment of the circadian modulation of HR.

Analysis of Variance↗
PubMed1983

REM latency: development in the first year of life.

The development of REM latency in the first year of life was investigated in two groups of 10 infants each. While 10 infants were normal, the other 10 underwent continuous feeding for various gastrointestinal diseases. Each infant was continuously recorded polygraphically for 24 h. While younger infants (less than or equal to 3 months) manifested predominantly shorter REM latencies (less than or equal to 8 min), older infants (4-13 months) produced a mixed distribution of short and long REM latencies. The total distribution of the REM latencies appears to be bimodal with latencies either shorter than 8 min or longer than 16 min. It is only in the group of older infants that the temporal distribution of REM latencies constitutes a diurnal rhythm, with the longest latencies in the interval between 12:00 and 16:00 and the shortest between 4:00 and 8:00. In the group of older infants, REM latency also depends on the duration of prior wakefulness. Long REM latencies are significantly more often preceded by long episodes of wakefulness than are short REM latencies. The different feeding conditions had only a minor effect on REM latency.

Humans↗
PubMed1983

Sinus pauses in early human malnutrition during waking and sleeping.

7 malnourished infants were studied before and after nutritional rehabilitation through long term polygraphic recordings during waking and sleeping. High amounts of sinus pauses (R-R interval comprised between 20 and 90% of the preceding interval) have been found in malnourished infants, mainly during quiet sleep. After the nutritional rehabilitation there is a dramatic reduction. The high amount of sinus pauses in infants suffering from severe malnutrition may reflect a disturbance of neurovegetative regulation, which is enhanced by sleep.

Arrhythmia, Sinus↗