Ultrasound for evaluation of fetal neurobehavioural development: from 2-D to 4-D ultrasound

From Traditional to Cutting-Edge: A Review of Fetal Well-Being Assessment Techniques

The birth of a new life, which should be a blessing to everyone, is regrettably not always the case. According to the latest data, the worldwide rate of stillbirths in 2022 stood at 13.9 stillbirths per 1,000 total births. This translates to one stillborn baby for every 72 total births, occurring at a frequency of one every 17 seconds. This article reviews antenatal fetal monitoring techniques that can help patients and healthcare providers recognize and intervene in a timely manner to prevent conditions that threaten fetal well-being. Various fetal well-being assessment methods have been explored. The most used techniques include the non-stress test, contraction stress test, and biophysical profile that encompass both fetal movement and fetal heart rate. This review delves into technologies used for antenatal diagnostic methods, ranging from traditional methods to contemporary advancements. The presented categories serve as a guide, recommending techniques tailored to specific pregnancy stages and observational purposes.

Developmental Roots of Human Self-consciousness

Human consciousness is considered in the perspective of early development. Infants and young children remind us that at its core, the problem of consciousness is primarily a problem of identity, in particular a problem of self-identity with others in mind. It is about how we feel and construe ourselves as an entity among other entities. It is about becoming co-conscious: Aware of oneself through the evaluative eyes of others. This development unfolds in the first 18 months of life, following major steps that are described, and arguably considered as a human trademark.

Ultrasound imaging based recognition of prenatal anomalies: a systematic clinical engineering review

For prenatal screening, ultrasound (US) imaging allows for real-time observation of developing fetal anatomy. Understanding normal and aberrant forms through extensive fetal structural assessment enables for early detection and intervention. However, the reliability of anomaly diagnosis varies depending on operator expertise and device limits. First trimester scans in conjunction with circulating biochemical markers are critical in identifying high-risk pregnancies, but they also pose technical challenges. Recent engineering advancements in automated diagnosis, such as artificial intelligence (AI)-based US image processing and multimodal data fusion, are developing to improve screening efficiency, accuracy, and consistency. Still, creating trust in these data-driven solutions is necessary for integration and acceptability in clinical settings. Transparency can be promoted by explainable AI (XAI) technologies that provide visual interpretations and illustrate the underlying diagnostic decision making process. An explanatory framework based on deep learning is suggested to construct charts depicting anomaly screening results from US video feeds. AI modelling can then be applied to these charts to connect defects with probable deformations. Overall, engineering approaches that increase imaging, automation, and interpretability hold enormous promise for altering traditional workflows and expanding diagnostic capabilities for better prenatal care.

Can 3-dimensional cranial ultrasound be used to successfully reconstruct a 2-dimensional image without compromising on image quality in a neonatal population?

BACKGROUND

Cranial ultrasound is frequently performed in neonatal intensive care units and acquiring 2-dimensional (D) images requires significant training. Three-D ultrasound images can be acquired semi-automatically.

OBJECTIVE

This proof-of-concept study aimed to demonstrate that 3-D study image quality compares well with 2-D. If this is successful, 3-D images could be acquired in remote areas and read remotely by experts.

MATERIALS AND METHODS

This was a prospective study of 20 neonates, who underwent both routine 2-D and 3-D cranial ultrasounds. Images were reconstructed into standard views extracted from the 3-D volume and evaluated by three radiologists blinded to the acquisition method. The radiologists assessed for the presence of anatomical landmarks and overall image quality.

RESULTS

More anatomical structures were identified in the 3-D studies (P<0.01). There was a trend that 3-D ultrasound demonstrated better image quality in the coronal plane, and 2-D in the sagittal plane, only reaching statistical significance for two coronal views and two sagittal views.

CONCLUSION

Overall, this study has demonstrated that 3-D cranial ultrasound performs similarly to 2-D and could be implemented into neonatal practice.

Fetal brain activity and the free energy principle

OBJECTIVES

To study whether the free energy principle can explain fetal brain activity and the existence of fetal consciousness via a chaotic dimension derived using artificial intelligence.

METHODS

In this observational study, we used a four-dimensional ultrasound technique obtained to collect images of fetal faces from pregnancies at 27-37 weeks of gestation, between February and December 2021. We developed an artificial intelligence classifier that recognizes fetal facial expressions, which are thought to relate to fetal brain activity. We then applied the classifier to video files of facial images to generate each expression category's probabilities. We calculated the chaotic dimensions from the probability lists, and we created and investigated the free energy principle's mathematical model that was assumed to be linked to the chaotic dimension. We used a Mann-Whitney test, linear regression test, and one-way analysis of variance for statistical analysis.

RESULTS

The chaotic dimension revealed that the fetus had dense and sparse states of brain activity, which fluctuated at a statistically significant level. The chaotic dimension and free energy were larger in the sparse state than in the dense state.

CONCLUSIONS

The fluctuating free energy suggests consciousness seemed to exist in the fetus after 27 weeks.

Artificial intelligence to understand fluctuation of fetal brain activity by recognizing facial expressions

OBJECTIVE

To examine whether artificial intelligence can achieve discoveries regarding fetal brain activity.

METHODS

In this observational study, the authors collected images of fetal faces using a four-dimensional ultrasound technique obtained from singleton pregnancies of outpatients in routine practice at 27 to 37 weeks of gestation between February 1 and December 31, 2021. The authors developed an artificial intelligence classifier to recognize seven facial expressions of fetuses, then applied it to video files of fetal facial images to generate the probabilities, as confidence scores, of each expression category. Discrete Fourier transform and chaotic analysis were used to investigate the scores. Mann-Whitney test, t test, variance test, and one-way analysis of variance were used for statistical analysis.

RESULTS

Facial expression changes were observed in cycles averaging 66 to 73 s. The power spectrum showed that mouthing and neutral expressions were the most prevalent. There was a difference between categories for the spectrum (p = 0.004). Two different states--dense and sparse--of confidence scores were discovered. The correlation dimension was 1.19 ± 0.22 and 1.33 ± 0.27 for dense and sparse, respectively (p = 0.047).

CONCLUSION

This method objectively and quantitatively demonstrated fetal brain activity and may provide insight into how the fetus spends its time in utero.

Automatic measurements of fetal intracranial volume from 3D ultrasound scans

Three-dimensional fetal ultrasound is commonly used to study the volumetric development of brain structures. To date, only a limited number of automatic procedures for delineating the intracranial volume exist. Hence, intracranial volume measurements from three-dimensional ultrasound images are predominantly performed manually. Here, we present and validate an automated tool to extract the intracranial volume from three-dimensional fetal ultrasound scans. The procedure is based on the registration of a brain model to a subject brain. The intracranial volume of the subject is measured by applying the inverse of the final transformation to an intracranial mask of the brain model. The automatic measurements showed a high correlation with manual delineation of the same subjects at two gestational ages, namely, around 20 and 30 weeks (linear fitting R2(20 weeks) = 0.88, R2(30 weeks) = 0.77; Intraclass Correlation Coefficients: 20 weeks=0.94, 30 weeks = 0.84). Overall, the automatic intracranial volumes were larger than the manually delineated ones (84 ± 16 vs. 76 ± 15 cm3; and 274 ± 35 vs. 237 ± 28 cm3), probably due to differences in cerebellum delineation. Notably, the automated measurements reproduced both the non-linear pattern of fetal brain growth and the increased inter-subject variability for older fetuses. By contrast, there was some disagreement between the manual and automatic delineation concerning the size of sexual dimorphism differences. The method presented here provides a relatively efficient way to delineate volumes of fetal brain structures like the intracranial volume automatically. It can be used as a research tool to investigate these structures in large cohorts, which will ultimately aid in understanding fetal structural human brain development.

Tail movements by late-term fetal pitvipers resemble caudal luring: prenatal development of an ambush predatory behaviour

With the advent of powerful imaging instruments, the prenatal behaviour of vertebrates has been discovered to be far more complex than previously believed, especially concerning humans, other mammals and birds. Surprisingly, the fetal behaviour of squamate reptiles (lizards, snakes and amphisbaenians), a group of over 11 000 extant species, are largely understudied. Using ultrasonography, 18 late-term pregnant copperhead snakes (Agkistrodon contortrix) from a single population were inspected for fecundity (number of fetuses). Unexpectedly, during the ultrasound procedure that involved 97 fetuses, we observed sinusoidal tail movements in 11 individuals from eight different copperhead mothers. These movements were indistinguishable from caudal luring, a mimetic ambush predatory strategy which is exhibited by newborn copperheads and other snakes. Caudal luring is initiated shortly after birth and is employed to attract susceptible vertebrate prey. Using the same ultrasound equipment and methods, we tested for this behaviour in two species of rattlesnakes (genus Crotalus) not known to caudal lure and none of the late-term fetuses showed any type of tail movements. Prenatal movements in humans and other vertebrates are known to be important for musculoskeletal and sensorimotor development. The fetal behaviours we describe for copperheads, and possibly other snakes, may be similarly important and influence early survival and subsequent fitness.

Recognition of facial expression of fetuses by artificial intelligence (AI)

OBJECTIVES

The development of the artificial intelligence (AI) classifier to recognize fetal facial expressions that are considered as being related to the brain development of fetuses as a retrospective, non-interventional pilot study.

METHODS

Images of fetal faces with sonography obtained from outpatient pregnant women with a singleton fetus were enrolled in routine conventional practice from 19 to 38 weeks of gestation from January 1, 2020, to September 30, 2020, with completely de-identified data. The images were classified into seven categories, such as eye blinking, mouthing, face without any expression, scowling, smiling, tongue expulsion, and yawning. The category in which the number of fetuses was less than 10 was eliminated before preparation. Next, we created a deep learning AI classifier with the data. Statistical values such as accuracy for the test dataset and the AI confidence score profiles for each category per image for all data were obtained.

RESULTS

The number of fetuses/images in the rated categories were 14/147, 23/302, 33/320, 8/55, and 10/72 for eye blinking, mouthing, face without any expression, scowling, and yawning, respectively. The accuracy of the AI fetal facial expression for the entire test data set was 0.985. The accuracy/sensitivity/specificity values were 0.996/0.993/1.000, 0.992/0.986/1.000, 0.985/1.000/0.979, 0.996/0.888/1.000, and 1.000/1.000/1.000 for the eye blinking, mouthing, face without any expression, scowling categories, and yawning, respectively.

CONCLUSIONS

The AI classifier has the potential to objectively classify fetal facial expressions. AI can advance fetal brain development research using ultrasound.

Clinical pointers from developing self-awareness

Seven typical developmental steps are described as cardinal changes leading children from implicit embodied self-awareness at birth, self-consciousness by 2 years, and the adoption of an ethical stance toward others by the preschool years (3-5y). This development may be a useful benchmark for clinicians. In this review, some clinical pointers are outlined in relation to each developmental step, but with a particular focus on the testing of self-awareness in children with developmental disorders, including autism spectrum disorder, cerebral palsy, and intellectual disability. WHAT THIS PAPER ADDS: There are seven major steps in early self and social awareness. Clinical pointers related to each of the seven steps are provided.

Change in fetal behavior in response to vibroacoustic stimulation

Objective To assess fetal behavioral changes in response to vibroacoustic stimulation (VAS) in normal singleton pregnancies using four-dimensional (4D) ultrasound. Methods Ten types of fetal movements and facial expressions in 68 healthy pregnant women between 24 and 40 weeks were studied using 4D ultrasound for 3 min before and after 3-s VAS. The frequencies of mouthing, yawning, tongue expulsion, back arch, jerky arm movement, startle movement, smiling, scowling, hand-to-face movement, and blinking were evaluated. The fetuses were subdivided into four gestational age groups (24-27, 28-31, 32-35, and ≥36 weeks). Comparison of the frequencies of the fetal behaviors before and after the stimulation in each gestational age group was conducted to detect the response to stimulation with advancing gestation. Results There were no significant differences in the frequency of each fetal behavior before and after VAS at 24-27, 28-31, and 32-35 weeks of gestation. However, the frequencies of blinking and startle movements were significantly higher after VAS in the 36-40 gestational age group (P < 0.05). Conclusion The age of 36 weeks of gestation might represent an advanced stage of brain and central nervous system development and maturation as the response to stimuli is prominent at this age compared with earlier gestation.

Self-Unity as Ground Zero of Learning and Development

Contrary to the suggestion that we are born in a state of confusion and primordial state of a-dualism with the environment, infancy research of the past 40 years shows that from the outset, infants are objective perceivers guided by rich evolved survival values of approach and avoidance in relation to specific resources in the environment such as faces, food, or smell. This starting-state competence drives and organizes their behavior. Evidence-based ascription of self-unity at birth is discussed. Selected findings are presented suggesting that self-unity is a primordial human experience, the main organizer of behavior from the outset. Self-unity is the necessary ground zero enabling the rapid learning and development taking place early in human life.

Effect of psychotropic drugs on fetal behavior in the third trimester of pregnancy

AIM

To assess the effect of psychotropic drugs on fetal behavior using four-dimensional (4D) ultrasound in the third trimester of pregnancy.

METHODS

Fetal behavior was assessed using Kurjak's antenatal neurodevelopmental test (KANET) using 4D ultrasound between 28 and 36 weeks of gestation. Thirty healthy (control group) and 10 psychotropic-drug-administered pregnant (case group) women were studied. The total value of the KANET score and values of each parameter (eight parameters) were compared between the two groups.

RESULTS

The total KANET score was normal (except for one fetus in the case group: total score of 9) in both groups, and there was no significant difference in the total KANET score. When individual KANET parameters were compared, no significant differences were noted in any of the eight parameters.

CONCLUSION

Our results showed that there is no difference in fetal behavior between fetuses of normal pregnant women and those of psychotropic-drug-administered pregnant women in the third trimester of pregnancy. These results suggest that psychotropic drugs may not affect fetal behavioral development in utero. However, the data and their interpretation in the present study should be taken with some degree of caution because of the small number of subjects studied. Further studies involving a larger sample size are needed to assess the effect of psychotropic drugs on fetal neurobehavior during pregnancy.

Effects of maternal anxiety and depression on fetal neuro-development

BACKGROUND

Fetal development is affected by maternal mental health with research indicating that maternal anxiety and depression are co-morbid; nevertheless differential effects on the fetus have been found. This study examines, prenatally, effects of maternal stress, anxiety and depression on fetal eye-blink reactions to experimental sound and light stimulation.

METHODS

Two groups of singleton fetuses (mean 32-weeks gestation) were examined using 4D ultrasound: a control group (N = 14, 7 female) with no stimulation and an experimental group (N = 21, 13 female) exposed to experimental sound, light and cross-modal stimulation. For both groups ultrasound scans were performed and fetal eye-blink was assessed. Mothers completed the Hospital-Anxiety-and-Depression Scale and the Perceived-Stress Scale. Analysis was carried out using Poisson mixed effects modelling.

RESULTS

Fetal eye-blink rate during experimental stimulation was significantly and differentially associated with maternal mental health with a 20% increase of fetal eye-blink rate for each unit increase in anxiety score (p = 0.02) and a decrease of 21% of eye blink rate for each unit of increase in depression score (p = 0.02). Sound stimulation but not light stimulation significantly affected blink-rate with fetuses habituating to the stimuli (p < 0.001).

LIMITATIONS

Limitations are the relatively small number of fetuses and that a follow up after birth is essential to establish potential long-term effects.

CONCLUSIONS

Of clinical importance is the finding that although fetuses are affected by maternal mental health in general here we demonstrate, using eye-blink-rate during stimulation as measure of neuro-development, that fetuses are differentially affected by maternal anxiety and depression with anxiety increasing and depression decreasing fetal reactivity significantly.

Clinical study of fetal neurobehavior by the KANET test

Fetal neurology is evolving as an area of great interest in prenatal diagnosis and fetal medicine. The identification and diagnosis of brain damage prenatally has been a great challenge in obstetrics for many years. Investigations of fetal behavior in comparison with morphological studies led to the conclusion that fetal behavioral patterns directly reflect developmental and maturational processes of the fetal central nervous system (CNS). Four-dimensional (4D) ultrasound has greatly improved the assessment of the quality of the fetal spontaneous movements, and enabled a better evaluation of fetal behavior. The assessment of normal neurobehavioral development by 4D ultrasound provided the opportunity to investigate functional characteristics of the fetus that could predict neurological developmental dysfunction. Some studies have already been carried out to evaluate this new methodology in the observation of fetal behavior during different stages of gestation, in an attempt to better understand the relationships between the maturation of the CNS of the fetus and its implications on its behavior pattern. We present a review of literature on fetal behavior by 4D ultrasound.

Species-specific Posture of Human Foetus in Late First Trimester

The ontogeny associated with the arm-hanging posture, which is considered ape-specific, remains unknown. To examine its ontogeny, we measured foetal movements of 62 human foetuses aged 10-20 gestation weeks using four-dimensional sonography. We observed that the first-trimester foetuses show this particular species-specific posture. After 11 weeks of gestation, all foetuses showed the arm-hanging posture, and the posture was most frequently observed at 14-16 weeks of gestation. Moreover, this posture often involved extension of both arms and both legs, indicating that it is not myogenic but neurogenic. Furthermore, early ontogeny suggests that it originates because of subcortical activity. Such posture extension bias and persistence indicates that vestibulospinal tract maturation involves the ontogeny of arm-hanging posture during 14-16 weeks of gestation.

4D ultrasound study of fetal movement early in the second trimester of pregnancy

AIM

To assess the frequency of fetal movement and reproducibility of fetal movement counting in normal singleton pregnancies early in the second trimester using four-dimensional (4D) ultrasound.

METHODS

Twenty-nine singleton pregnancies were studied for 15 min employing 4D ultrasound at 14-16 (19 cases) and 17-19 (10 cases) weeks of gestation. The frequencies of eight fetal movements (head anteflexion, head retroflexion, body rotation, hand to face movement, general movement, isolated arm movement, isolated leg movement and mouthing movement) were evaluated.

RESULTS

The most frequent fetal movements were isolated arm movements at 14-16 and 17-19 weeks' gestation. There was a significant difference only in the frequency of mouthing movement between 14-16 and 17-19 weeks' gestation (P<0.05). All fetal movements showed intra- and inter-class correlation coefficients greater than 0.87, with good intra- and inter-observer agreements.

CONCLUSION

The difference in the frequency of mouthing movement at 14-16 and 17-19 weeks' gestation may be due to increasing fetal swallowing because of the increasing amniotic fluid early in the second trimester of pregnancy. To the best of our knowledge, this is the first study on the reproducibility assessment of fetal movement counting using 4D ultrasound. However, the data and their interpretation in the present study should be taken with some degree of caution because of the small number of subjects studied. Further studies involving a larger sample size are needed to assess the reproducibility of fetal movement counting using 4D ultrasound.

Fetal face as important indicator of fetal brain function

Fetuses show various facial expressions, such as blinking, yawning, sucking, mouthing, tongue expulsion, scowling, and smiling, assessed by four-dimensional ultrasound from the early second trimester of pregnancy. Moreover, some fetuses demonstrate emotion-like behaviors as noted in infants, children, and adults. Selective fetal responses to stimuli indicate a high degree of brain development, which is reflected in the facial reactions. The fetal face with its movements and expressions can mirror the fetal brain function and development during different stages of the fetus in utero. The fetal face might represent the key to opening the box containing the secrets of fetal brain function and development. Four-dimensional ultrasound may be an important modality in current and future research on fetal facial expressions and assist in the evaluation of the fetal brain function.

4D ultrasound study of fetal facial expressions in the third trimester of pregnancy

OBJECTIVE

To evaluate the frequencies of fetal facial expressions in the third trimester of pregnancy, when fetal brain maturation and development are progressing in normal healthy fetuses.

METHODS

Four-dimensional (4 D) ultrasound was used to examine the facial expressions of 111 healthy fetuses between 30 and 40 weeks of gestation. The frequencies of seven facial expressions (mouthing, yawning, smiling, tongue expulsion, scowling, sucking, and blinking) during 15-minute recordings were assessed. The fetuses were further divided into three gestational age groups (25 fetuses at 30-31 weeks, 43 at 32-35 weeks, and 43 at ≥36 weeks). Comparison of facial expressions among the three gestational age groups was performed to determine their changes with advancing gestation.

RESULTS

Mouthing was the most frequent facial expression at 30-40 weeks of gestation, followed by blinking. Both facial expressions were significantly more frequent than the other expressions (p < .05). The frequency of yawning decreased with the gestational age after 30 weeks of gestation (p = .031). Other facial expressions did not change between 30 and 40 weeks. The frequency of yawning at 30-31 weeks was significantly higher than that at 36-40 weeks (p < .05). There were no significant differences in the other facial expressions among the three gestational age groups.

CONCLUSIONS

Our results suggest that 4D ultrasound assessment of fetal facial expressions may be a useful modality for evaluating fetal brain maturation and development. The decreasing frequency of fetal yawning after 30 weeks of gestation may explain the emergence of distinct states of arousal.

Current status of fetal neurodevelopmental assessment: Four-dimensional ultrasound study

With the latest advent of four-dimensional (4-D) ultrasound, fetal neurobehavioral or neurodevelopmental assessment can be easily and readily performed. Using this technique, typical fetal movements and behavioral patterns have become apparent in all three trimesters of pregnancy. In twin pregnancy, 4-D ultrasound facilitates the precise evaluation of inter-twin contact and intra-pair stimulation. New fetal neurobehavioral assessment tests, such as Kurjak's Antenatal Neurodevelopmental Test and the Fetal Observable Movement System, may reflect the normal and abnormal neurological development of the fetus, and will facilitate more precise assessments of fetal neurobehavior or neurodevelopment, and fetal brain and central nervous system functions. In this review article, I also discuss interesting topics regarding maternal and fetal stress, fetal pain, and fetal consciousness. Four-dimensional ultrasound has opened the door to new scientific fields, such as 'fetal neurology' and 'fetal psychology,' and fetal neurobehavioral science is at the dawn of a new era. Knowledge on fetal neurobehavior and neurodevelopment will be advanced through fetal behavioral research using this technique.

HDlive and 4D Ultrasound in the Assessment of Fetal Facial Expressions

Four-dimensional (4D) sonographic assessment of fetal facial expressions is considered to reflect normal and abnormal fetal neurological developments, and may be an important clue to predict the fetal brain function and well-being before and after birth. HDlive is a new surface-rendering mode, which uses an adjustable light source that facilitates the ability to create lighting and shadowing effects, thereby increasing depth perception. This technique facilitates extraordinarily realistic imaging of the fetal face, making it almost impossible to differentiate between actual photographs and HDlive images. In this article, we discuss recent topics regarding fetal facial expressions assessed by 4D ultrasound and HDlive, focusing on mouthing, sucking, yawning, blinking, tongue expulsion, scowling (pain/distress), and smiling. Moreover, we consider possibility of the existence of fetal emotion or awareness.

How to cite this article

Hata T, Kanenishi K, Hanaoka U, Marumo G. HDlive and 4D Ultrasound in the Assessment of Fetal Facial Expressions. Donald School J Ultrasound Obstet Gynecol 2015;9(1):44-50.

HDlive Study of Fetal Development and Behavior

We present the latest HDlive studies of fetal development and behavior during pregnancy. Marked changes of embryonic and fetal development and movement with advancing gestation were noted in the first trimester of pregnancy. Various realistic facial expressions (or facial movements) were recognized in the second and third trimesters. In particular, blinking, mouthing, swallowing, yawning, tongue expulsion, and sucking were clearly depicted. Moreover, various extraordinarily realistic features of fetal emotion-like behavior were identified. HDlive observation of fetal behavior and facial expressions may reflect the normal and abnormal neurological development of the fetus. HDlive may become an important modality in future research on fetal neurobehavioral development and assist in evaluation of the fetal brain function.

How to cite this article

Hata T, Kanenishi K, Hanaoka U, Uematsu R, Marumo G, Tanaka H. HDlive Study of Fetal Development and Behavior. Donald School J Ultrasound Obstet Gynecol 2014;8(3):250-265.

Can healthy fetuses show facial expressions of "pain" or "distress"?

BACKGROUND

With advances of research on fetal behavioural development, the question of whether we can identify fetal facial expressions and determine their developmental progression, takes on greater importance. In this study we investigate longitudinally the increasing complexity of combinations of facial movements from 24 to 36 weeks gestation in a sample of healthy fetuses using frame-by-frame coding of 4-D ultrasound scans. The primary aim was to examine whether these complex facial movements coalesce into a recognisable facial expression of pain/distress.

METHODOLOGY/FINDINGS

Fifteen fetuses (8 girls, 7 boys) were observed four times in the second and third trimester of pregnancy. Fetuses showed significant progress towards more complex facial expressions as gestational age increased. Statistical analysis of the facial movements making up a specific facial configuration namely "pain/distress" also demonstrates that this facial expression becomes significantly more complete as the fetus matures.

CONCLUSIONS/SIGNIFICANCE

The study shows that one can determine the normal progression of fetal facial movements. Furthermore, our results suggest that healthy fetuses progress towards an increasingly complete pain/distress expression as they mature. We argue that this is an adaptive process which is beneficial to the fetus postnatally and has the potential to identify normal versus abnormal developmental pathways.

Four-dimensional HDlive rendering image of fetal facial expression: a pictorial essay

BACKGROUND

Our objective was to present our experience of fetal facial expressions reconstructed employing the four-dimensional (4D) HDlive rendering mode.

METHODS

A total of 23 normal fetuses at 18-36 weeks' gestation were studied using the 4D HDlive rendering mode.

RESULTS

The 4D HDlive rendering mode provided extraordinarily realistic features of the fetal face. In particular, blinking, mouthing, swallowing, yawning, tongue expulsion, and sucking were clearly noted. Moreover, various realistic fetal emotional expressions such as smiling-like and crying-like movements were recognized. The 4D HDlive rendered images of fetal facial expressions seem to be more readily discernible than those obtained by conventional 4D ultrasonography.

CONCLUSION

Observation of facial expressions using the 4D HDlive rendering mode is considered to reflect the normal and abnormal neurological development of the fetus. Therefore, the 4D HDlive rendering mode may assist in evaluation of fetal brain function, and offer potential advantages relative to conventional 4D ultrasonography.

Neurobehavior in fetal life

Assessment fetal behavior gave a promising opportunity to understand the hidden function of the developmental pathway of the fetal central nervous system. After the assessment of normal neurobehavioral development by four-dimensional (4D) ultrasound, attempts have been made to identify functional characteristics of the fetus that predict a range of subsequent developmental dysfunction. These attempts resulted in producing the Kurjak Antenatal Neurodevelopmental Test (KANET). Assessment of fetal behavior by 4D ultrasound and application of KANET scoring test has been recently published in several journals and summarized results are presented in this review.

Development of fetal yawn compared with non-yawn mouth openings from 24-36 weeks gestation

Background

Although some research suggests that fetuses yawn, others disagree arguing that is it simple mouth opening. Furthermore there is no developmental account of fetal yawning compared with simple mouth opening. The aim of the present study was to establish in a repeated measures design the development of fetal yawning compared with simple mouth opening.

Methodology/Findings

Video recordings were made of the fetal face and upper torso visualized by means of 4D full frontal or facial profile ultrasound recordings. Fifteen healthy fetuses were scanned four times at 24, 28, 32 and 36 weeks gestation. Yawning was distinguished from non-yawning in terms of the length of time it took to reach the apex of the mouth stretch, with yawns being defined as more than 50% of the total time observed. To assess changes in frequency, a Poisson mixed effects model was fitted to the count of number of yawn and simple mouth opening events with age and gender as fixed effects, and person as a random effect. For both yawns and simple mouth openings a smooth varying age effect was significant. The number of yawns observed declined with age from 28 weeks gestation, whereas simple mouth openings were less frequent and the decline was observed from 24 weeks. Gender was not significant either for yawn and simple mouth openings.

Conclusions/Significance

Yawning can be reliably distinguished from other forms of mouth opening with the potential of using yawning as an index of fetal healthy development.

Three- and four-dimensional HDlive rendering images of normal and abnormal fetuses: pictorial essay

BACKGROUND

Our objective is to present our experience of normal embryonic development and fetal anatomy and fetal anomalies reconstructed employing the three-dimensional (3D) and four-dimensional (4D) HDlive rendering mode.

METHODS

A total of 18 normal embryos and fetuses and 21 abnormal fetuses (one case each of thoracic meningocele, thickened nuchal translucency, multicystic dysplastic kidney, gastroschisis, omphalocele, and ovarian cyst, five of hydrops fetalis, three of skeletal abnormality, three of chromosome abnormality, two of cystic hygroma, and two of amniotic band syndrome) at 7-36 weeks' gestation were studied using the 3D/4D HDlive rendering mode.

RESULTS

In normal fetuses, marked embryonic development with advancing gestation was clearly shown in the first trimester of pregnancy, and various realistic facial expressions were noted in the second and third trimesters. In abnormal fetuses, anatomically realistic features such as gross specimens were obtained. In particular, 3D/4D HDlive provides new, realistic sensations for the diagnosis of amniotic band syndrome, skeletal abnormalities, and facial abnormalities.

CONCLUSION

3D/4D HDlive rendering images seem to be more readily discernible than those obtained by conventional 3D/4D sonography. 3D/4D HDlive may be an important modality in future embryonic research, fetal neurobehavioral assessment, and the evaluation of fetal anomalies.

4D Sonography in Assessment of Fetal Neurobehavior

‘Observation of fetal behavior reflects the functioning of the central nervous system, and behavioral assessment of the fetus enables the function of the brain to be examined’.1 The introduction of four-dimensional (4D) sonography techniques would facilitate fetal behavioral assessment in three dimensions in real time during pregnancy. We describe the latest 4D sonographic studies on fetal neurobehavior in all three trimesters of pregnancy. 4D sonography also facilitated the evaluation of interhuman contact and intrapair stimulation in twin pregnancies in utero. This novel technique may assist in the evaluation of fetal neurobehavior and intertwin contact and intrapair stimulation and offer potential advantages relative to conventional two-dimensional sonography. 4D sonography may become an important modality in future research on fetal neurobehavioral development and the prenatal identification of severely brain-damaged infants.

How to cite this article

Hata T, Sato M, Kanenishi K, Hanaoka U, Tanaka H. 4D Sonography in Assessment of Fetal Neurobehavior. Donald School J Ultrasound Obstet Gynecol 2012;6(2):121-131.

Fetal reflex movement in twin pregnancies late in the first trimester: 4-D sonographic study

The objective of this study was to evaluate reactions to touch in utero between twin fetuses using 4-D sonography late in the first trimester of pregnancy. Six monochorionic diamniotic (MD) and eight dichorionic diamniotic (DD) pregnancies were studied for 30 min with transabdominal 4-D sonography at 12-13 weeks' gestation. The frequencies of no reaction (twins appear to touch each other but there is no clear reaction) and reaction (twins appear to touch each other and there is a clear reaction by the co-twin) movements were evaluated. There was no significant difference in the rate of reaction movements between MD (median, 33.6%) and DD (median, 33.9%) twins. The median rate of reaction movements in all 14 twins was 33.9% (range, 27 to 64.1%). Our findings suggest that the incidence of reflex movement of the co-twin on being touched by the other twin late in the first trimester is more frequent than that assessed by conventional 2-D ultrasound.

An Attempt to Standardize Kurjak's Antenatal Neurodevelopmental Test: Osaka Consensus Statement

Analysis of the dynamics of fetal behavior in comparison with morphological studies has led to the conclusion that fetal behavioral patterns are directly reflecting developmental and maturational processes of fetal central nervous system (CNS). Four-dimensional ultrasound (4D US) offers a practical means for assessment of both the brain function and structure. The visualization of fetal activity in utero by 4D US could allow distinction between normal and abnormal behavioral patterns which might make possible the early recognition of fetal brain impairment. That new technology enabled introduction of Kurjak's antenatal neurodevelopmental test (KANET) in low- and high-risk pregnancies. In order to make the test reproducible, the standardization of the test was proposed in Osaka, Japan, during the International Symposium on Fetal Neurology of International Academy of Perinatal Medicine.

The KANET should be performed in the 3rd trimester from 28th to 38th week of gestation. The assessment should last from 15 to 20 minutes, and the fetuses should be examined when awake. If the fetus is sleeping, the assessment should be postponed for 30 minutes or for the next day between 14 and 16 hours. In cases of definitely abnormal or borderline score, the test should be repeated every two weeks till delivery. New modified KANET test should be used with eight instead of 10 parameters: Facial and mouth movements are combined in one category, isolated hand movements and hand to face movements are combined in one category. The score should be the same for abnormal fetuses 0 to 5, borderline score is from 6 to 13 and normal score is 14 or above.

After 4D US assessment of behavioral patterns in the fetuses from high-risk pregnancies, it is very important to continue with follow-up after delivery in infants who were borderline or abnormal as fetuses. Postnatal assessment of neonates includes initial neurological assessment according to Amiel-Tison's methodology (Amiel-Tison Neurological Assessment at Term, ATNAT) in the early neonatal period and every two weeks in preterm infants till discharge and at the postmenstrual age (PMA) between 37 and 40 weeks. If ATNAT is borderline or abnormal, initial assessment of general movements at the age of 36 to 38 weeks of PMA should be performed, than at writhing age (between 46 and 52 weeks), and at the fidgety age after 54 weeks of PMA. If the finding of fidgety movements is mildly abnormal or definitely abnormal, then one more assessment should be done in 2 to 4 weeks till PMA of 58 weeks. Brain ultrasonography should be performed in the first week of life and every 2 weeks afterward till discharge. In severely affected infants with grade 3 and above intraventricular hemorrhage, and those highly suspicious of hypoxic ischemic brain damage, magnetic resonance (MR) should be done if available. Infants should be followed until the age of at least 24 months when diagnosis of disabling or nondisabling cerebral palsy can be ultimately made. Infants with CP should be reassessed at the age of 6 years.

Four-dimensional Ultrasound Evaluation of Fetal Neurobehavioral Development

The introduction of four-dimensional (4D) ultrasound techniques would facilitate fetal behavioral assessment in three-dimensions in realtime during pregnancy. We describe the latest 4D sonographic studies on fetal behavior, especially fetal whole-body movements and facial expressions in all three trimesters of pregnancy and the continuation of behavior from the fetal to neonatal period. Moreover, we introduce a new scoring system (KANET, Kurjak Antenatal Neurological Test) for assessment of the fetal neurological status using 4D ultrasound. 4D ultrasound also facilitated the evaluation of inter-human contact in twin pregnancies in utero. This novel technique may assist in the evaluation of fetal behavior and inter-twin contact, and offer potential advantages relative to conventional two-dimensional ultrasound. 4D ultrasound should become an important modality in future research on fetal neurobehavioral development and the prenatal identification of severely brain-damaged infants. Further studies involving a larger sample size are needed to ascertain the role of 4D ultrasound in the evaluation of fetal neurobehavioral development.