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.