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Biomedical subjects

H F Prechtl

Publications and source records attributed to H F Prechtl.

At least 73 records · Page 4Linked to original sources
PubMed1986

The blood flow velocity waveform in the fetal descending aorta; its relationship to behavioural states in the growth-retarded fetus at 37-38 weeks of gestation.

In 12 patients with intrauterine growth retardation (IUGR), the relationship between the blood flow velocity waveform at the lower thoracic level of the fetal descending aorta and fetal behavioural states at 37-38 wk of gestation was studied. A significant inverse relationship (P less than 0.001) was established between pulsatility index (PI) and fetal heart rate (FHR) in state 1F and 2F. The PI as a measure of peripheral vascular resistance, demonstrated a marked increase compared to normal pregnancy. There is a virtual overlap of PI values originating from state 1F and 2F according to the classification by Nijhuis et al. (J.G. Nijhuis, H.F.R. Prechtl, C.B. Martin, Jr. and R.S.G.M. Bots (1982) Early Hum. Dev. 6, 177-195). The peripheral vasoconstriction present in IUGR seems to overrule state dependent PI fluctuations. The marked rise in PI, particularly at lower FHR and the constancy of PI in relation to fetal behavioural states can be considered vascular adaptations, which are instrumental in the centralization of the fetal circulation, with the aim of favouring blood supply to the brain, heart and adrenals during IUGR.

Aorta, Thoracic↗
PubMed1986

Developmental transformations of spontaneous movements in early infancy.

One component of the major transformation of neural functions at the end of the second postnatal month is concerned with a change in the appearance of general movements. These endogenously generated complex movements lose their writhing character and are replaced by a transient form, termed 'fidgety' movements. There are individual differences in the age of onset and duration as revealed by longitudinal observations. It is speculated that 'fidgety' movements may be related to a postnatal calibration of the proprioceptive system.

Aging↗
PubMed1986

Abnormal fetal behavioural state regulation in a case of high maternal alcohol intake during pregnancy.

In the near term human fetus disturbed behavioural state organization has been found in cases of intra-uterine growth retardation or maternal type-1-diabetes. The present case report describes abnormal fetal behavioural state organization found in combination with maternal alcohol abuse during pregnancy. The abnormalities included frequent interruptions of the periods of concordant association of 2F-parameters, reflected by a high proportion of no-coincidence, and spontaneous awakenings (State 4F), always following stable periods of State 1F. The latter phenomenon was not found thus far by us or others, neither in normal nor in complicated pregnancies. After birth normal state organization was found. It is suggested that the abnormalities in fetal behaviour might have been due to maternal alcohol abuse, whereas a possible withdrawal effect might have occurred in utero.

Adult↗
PubMed1985

The relationship between fetal activity and behavioral states and fetal breathing movements in normal and growth-retarded fetuses.

The incidence of fetal breathing was studied during the course of behavioral state observations on 28 low-risk fetuses between 32 and 40 weeks' gestational age and on 12 growth-retarded fetuses between 36 and 40 weeks. Real-time ultrasound scanners were used to detect fetal eye, body, and breathing movements, and the fetal heart rate was recorded continuously. The mean duration of the observation sessions was 110 minutes. The mean incidence of fetal breathing was greater during periods of fetal activity (body and eye movements present, greater heart rate variability) than during quiescence (body and eye movements absent, narrowed heart rate variability) at all gestational ages studied in both low-risk and growth-retarded fetuses. During periods when one of the state variables (body movements, eye movements, heart rate pattern) was in its active condition while the other two were quiet, or the reverse, the incidence of fetal breathing was intermediate between those found when all three state variables were in agreement. After behavioral states had developed, at 38 and 40 weeks, the mean incidence of fetal breathing in the low-risk fetuses was greater during active states than during the quiet state. There was no apparent increase in the degree of linkage between fetal breathing and other expressions of fetal activity after the emergence of behavioral states.

Eye Movements↗
PubMed1985

The emergence of fetal behaviour. II. Quantitative aspects.

In a longitudinal study of 12 healthy nulliparous women the developmental course of specific fetal movement patterns was investigated in the first half of gestation, using real-time ultrasound. The rate of occurrence of all movement patterns emerging during this period is presented. There were large differences in incidence between the various movements. In most of them a developmental trend was found, either a gradual increase in incidence as the fetus grew older (breathing movements, head rotations, jaw openings, sucking and swallowings), an increase in incidence until a plateau was reached (general movements, isolated arm movements), or an increase in incidence followed by a decrease (startles, hiccups, hand/face contacts, retroflexions of the head). In a few infrequently occurring movements no developmental trends could be observed (isolated leg movements, anteflexions of the head, yawns, stretches) whereas in some of the more frequently occurring movements a lower limit of the normal range could be defined. A few movement patterns were found to be generated at a more or less regular interval: hiccups occurred with a preference interval of one to three seconds and isolated arm movements with an interval of about 1 s. Breathing movements showed a clear developmental shift in preference interval. Between 10 and 19 weeks this changed from 2 to 3 s to less than 1 s. The majority of movements, however, seemed to occur at no regular interval or the regularity was missed because the burst length was too short. Quantification of fetal quiescence showed that in between 8 and 19 weeks total absence of movements never lasted longer than 13 min.

Arm↗
PubMed1985

Behavioural states in the fetuses of nulliparous women.

Behavioural state observations were carried out serially on the fetuses of 14 low risk nulliparae. They were observed serially at 2-weekly intervals between 32 weeks gestational age and delivery at term. Two real-time ultrasound B-scanners were used to visualize fetal body, eye and breathing movements. Fetal heart rate patterns were recorded simultaneously by means of a clinical fetal monitor. States appeared to be present transiently in three fetuses at 34 weeks. States were definitely present in five of 13 fetuses studied at 38 weeks and six of seven observed at 40 weeks. In comparison to the fetuses of low risk multiparae studied earlier, the fetuses in the present study showed a somewhat lower proportion of quiescence (coincidence 1F) and higher percentage of activity (coincidence 2F); however, most of these differences were not statistically significant. In the fetuses which showed states, the distribution and durations of the states at 38 and 40 weeks were not different from those found previously in the fetuses of multiparae. We conclude that the development of behavioural states is generally similar in the fetuses of low risk nulliparae and multiparae, but that states appear at a somewhat later gestational age in the fetuses of nulliparae.

Eye Movements↗
PubMed1985

The blood flow velocity waveform in the fetal descending aorta: its relationship to fetal behavioural states in normal pregnancy at 37-38 weeks.

In 13 normal pregnancies, the relationship between the blood flow velocity waveform at the lower thoracic level of the fetal descending aorta and fetal behavioural states at 37-38 weeks of gestation was studied. The pulsatility index (PI), as a measure of peripheral vascular resistance, was significantly lower during state 2F compared to state 1F according to the classification by Nijhuis et al. (Nijhuis, J.G. et al. (1982) Early Hum. Dev., 6, 177-195), suggesting an increased perfusion of the fetal skeletal musculature to meet the energy demand needed for the raised muscular activity during state 2F; A significant inverse relationship (P less than 0.001) was established between PI and FHR in state 2F; this was mainly determined by a significant rise in end-diastolic flow velocity (P less than 0.02). Both the behavioural state and FHR should be taken into account when evaluating flow velocity waveforms in the fetal descending aorta during the latter weeks of pregnancy.

Aorta↗
PubMed1985

Motor behaviour in the growth retarded fetus.

In ten growth retarded fetuses (IUGR) a qualitative and quantitative analysis was made of various movement patterns. The results were compared with those of ten matched appropriate-for-gestational age fetuses (AGA). The aim of the study was to see whether malnourished, growth retarded fetuses move differently to well nourished, normal fetuses. The real-time ultrasound recordings were of one hour's duration and the analysis of motility was carried out during replay of video recordings. The qualitative analysis of each separate general movement was performed with 'Gestalt perception' describing the speed, force and amplitude of each movement as well as the variability of these descriptors. Interobserver agreement was evaluated by displaying general movements of both groups to 8 observers. There was an overall interobserver agreement of 89%. The IUGR fetuses moved less, but in individual cases an overlap existed with control fetuses. There was a reduction of both number and duration of general movements in the IUGR group. Furthermore the markedly reduced incidence of startles, twitches and isolated limb movements was striking. The qualitative analysis of general movements revealed a reduction of the quicker components leading to slow and monotonous movement patterns. There was also a marked reduction of variability of speed and intensity within each movement pattern. We speculate that the reduced variability of motor patterns may find its origin in a change of central neural function, just as the reduced heart rate variability and decreased breathing irregularity found in IUGR fetuses.

Adult↗
PubMed1985

Abnormal motor behaviour in anencephalic fetuses.

In eight anencephalic fetuses ultrasound observations of movement patterns were made and correlated with the morphological findings at postmortem. In all fetuses the movements were qualitatively abnormal: they were forceful, jerky in character and of large amplitude. In some of the most defective cases classification of the movements was hardly possible as they showed little similarity to those observed in normal fetuses. In these cases movements tended to occur in burst-pause patterns in contrast to being scattered over the record. Excessive activity occurred also only in the more defective cases. In fetuses with no evident cervical cord present isolated arm movements were observed. Fetal lung hypoplasia occurred as early as 16 weeks and in a fetus which showed both hiccups and breathing movements. It is concluded that with a severely defective fetal central nervous system, already in the first half of pregnancy movement patterns are abnormal. This abnormality mainly concerns the quality of the different movements. Secondly, movements can occur despite severe reduction in the amount and alteration in the organisation of the fetal central nervous system.

Anencephaly↗
PubMed1985

Behavioural states in growth-retarded human fetuses.

Behavioural state observations were carried out on 12 fetuses which subsequently had birthweights below the 10th percentile. Their gestational ages at the time of study ranged from 32 to 40 weeks. Real-time ultrasound scanning was used to detect fetal body and eye movements, and the fetal heart rate was continuously recorded using a clinical fetal monitor. None of these fetuses was severely acidemic or depressed at birth. Findings in the growth-retarded fetuses were compared with those obtained in the fetuses of 14 low risk nulliparae and 14 low risk multiparae by means of the same techniques (van Vliet et al. (1985) Early Hum. Dev., 12, 121-135.; Nijhuis et al. (1982) Early Hum. Dev., 6, 177-195). The appearance of states seemed to be delayed in the growth-retarded fetuses. States were present in only three of eight growth-retarded fetuses studied at 40 weeks, whereas only one of 16 low risk fetuses did not show states at this age. Also at 40 weeks, the proportion of discordant association of the state variables was increased in the growth-retarded fetuses in comparison to the low risk group. There were no consistent differences between the two groups in the occurrence of defined combinations of parameters of the state variables at earlier ages. The growth-retarded fetuses showed differences in the quality and quantity of somatic motility in comparison to low risk fetuses of equivalent gestational age. These observations suggest that some aspects of central nervous system function are disturbed in growth-retarded fetuses, even in the absence of fetal distress.

Birth Weight↗
PubMed1983

Eye movements in the human fetus and newborn.

The human oculomotor system becomes active long before birth. At about 16 weeks (post-menstrual age) the first slow changes of eye position can be observed with the aid of real time ultrasonography. At 18-20 weeks more rapid eye movements are detectable. There is a gradual decline in the percentage of time spent in rapid and slow eye movements from 32-40 weeks. These eye movements are organized in episodes of activity, divided by episodes of quiescence which are at first unrelated to cyclical changes in other variables (such as breathing movements, body movements and fetal heart rate patterns). At about 36 weeks gestation, REM and non-REM episodes become linked with other changes and then represent behavioural states identical to those seen in the newborn infant. This organization of behavioral states in the fetus is identical with that found in preterm infants of comparable age. Opening of eyelids is difficult to see before birth but the existence of episodes of wakefulness seems most probable. Hence fetal eye movements will be in part related to wakefulness. In the newborn at term, the interval distributions of REMs during sleep and of scanning eye movements during wakefulness are statistically different.

Eye Movements↗
PubMed1982

Are there behavioural states in the human fetus?

The aim of this study was to search for the existence of behavioural states in the human fetus and to describe their developmental course. In a longitudinal study, 14 low-risk fetuses were studied at 2-week intervals from 32 weeks of gestation onward. Fetal body movements as well as fetal eye movements, visualized by means of real-time ultrasonic imaging, and fetal heart rate patterns, recorded by means of a cardiotocograph, were used as state variables. At 38 and 40 weeks, four distinct behavioural states, named states 1F through 4F and corresponding respectively to states 1 through 4 of the neonate, could be identified. That these constellations of parameters represented true behavioural states was demonstrated by the stability of association of parameters for prolonged periods and by the simultaneity of change of parameters at state transitions. There is evidence for episodes of wakefulness in the fetus. Before 36 weeks, cycles were present in each of the state variables and combinations of parameters typical of particular states were observed. However, the relatively short durations of these combinations and the lack of simultaneity of change in the three state variables support the conclusion that these periods of coincidence occurred by chance and did not represent organized behavioural states.

Activity Cycles↗
PubMed1981

Human fetal eye movements: detection in utero by ultrasonography.

Eye movements of the human fetus were detected in utero by means of real-time B-scan and M-mode ultrasonography. In 14 low-risk fetuses studied between 32 weeks menstrual age and term either rapid or slow eye movements or a mixture of both types were detected in 60 +/- 10% (mean +/- SD) of 558 2 min scoring epochs. A comparison of direct echoscopic detection of eye movements in a 3-day-old neonate confirmed that the movements observed in the orbital region with the real-time scanner corresponded well with eye movements seen directly. Thus eye movements can be added to the list of phenomena which can be observed noninvasively for the study of human fetal behaviour.

Age Factors↗
PubMed1980

Heart rate as an indicator of the behavioral state. Studies in the newborn infant and prospects for fetal heart rate monitoring.

Term healthy newborn infants underwent polygraphy between days 4 and 6 of life. Behavioral states were determined according to Prechtl's criteria. The neonatal heart rate was analyzed for the various behavioral states, with the use of quantitative indices for long-term and short-term irregularity. The applied indices were, respectively, the long-term irregularity index (LTI index) and the interval difference index (ID index). During state 1 the R-R interval length was longer (p less than 0.01), the LTI index lower (p less than 0.01), and the ID index higher (p less then 0.02) than in the immediately preceding or following state 2. For nonconsecutive states 1 and 2 a maximum separation was obtained with the discriminant function 0.0159 RR - 0.065 LTI + 0.062 ID - 7.49. This discriminant function gave a total percentage of correct classification of states 1 and 2 epochs of 93%. The data are discussed with respect to the presence of cycling sleep states in the newborn infant as well as in the fetus. Prospects for fetal antepartum heart rate monitoring are considered.

Behavior↗