Eye-Hand-Mouth Coordination in the Human Newborn.

BACKGROUND: There have been several studies concerning rudimentary coordination of the eyes, hands, and mouth in the human newborn. The author attempted to clarify the ontogenetic significance of the coordination during the earliest period of human life through a systematic review. The neural mechanism underlying the coordination was also discussed based on the current knowledge of cognitive neuroscience. METHODS: Searches were conducted on PubMed and Google Scholar from their inception through March 2017. RESULTS: Studies have demonstrated that the coordination is a visually guided goal-directed motor behavior with intension and emotion. Current cognitive research has proved that feeding requires a large-scale neural network extending over several cortices. CONCLUSION: The eye-hand-mouth coordination in the newborn can be regarded as a precursor of subsequent self-feeding, and the coordination is very likely mediated through the underdeveloped but essentially the same network interconnecting cortices as in the adult.

Eye-Mouth Associated Movement in the Human Newborn and Very Young Infant.

BACKGROUND: The aim of this study is to demonstrate that goal-directed eye-mouth associated movement exists in the newborn and very young infant. METHODS: The participants were 17 healthy term newborns or very young infants whose ages at the time of the first examination ranged from 1 to 24 days. The examiner held the tip of an index finger 20 to 30 cm in front of a participant's mouth, then suddenly moved it directly toward the mouth. Thirteen of the participants were also examined with the examiner's palm as the visual stimulus. The response was judged to be positive if clear mouth opening was elicited as the fingertip or palm was approaching the mouth. RESULTS: In the examinations using a fingertip, the frequency of a positive response as to the total number of examinations in the different age groups within the first two months of life ranged between 43.9% and 48.8%, and precipitously decreased to 6.3% at two months of age. A positive response was not elicited from age three months. On the other hand, in the examinations using a palm, the frequency of a positive response was 5.0% in the newborns, and 6.7% in the infants aged between seven days and one month. A positive response was never obtained from two months of age. CONCLUSION: This study demonstrated that visually guided mouth opening toward an approaching target exists in the human newborn. The eye-mouth associated movement may be controlled through rudimentary but functional visuomotor circuits in the brain interconnecting different cortices.

The babkin reflex in infants: clinical significance and neural mechanism.

BACKGROUND: There have been very few studies concerning the Babkin reflex-opening of the mouth and flexion of the arms in response to stimulation of the palms. We attempted to clarify the clinical significance and neural mechanism of the reflex through systematic review. METHODS: Searches were conducted on Medline, Embase, and Google Scholar from their inception through August 2012. RESULTS: In normal term infants, the Babkin reflex can be elicited from the time of birth, becomes increasingly suppressed with age, and disappears in the great majority by the end of the fifth month of age. A marked response in the fourth or fifth month of age and persistence of the reflex beyond the fifth month of age are generally regarded as abnormal. On the other hand, because there are some normal infants showing no response during the neonatal period or early infancy, the absence of the response during these periods is not necessarily an abnormal finding. CONCLUSIONS: Infants with these abnormal findings should be carefully observed for the appearance of neurological abnormalities including cerebral palsy and mental retardation. It is most likely that the Babkin reflex is mediated by the reticular formation of the brainstem, which receives inputs from the nonprimary motor cortices. On the basis of the hand-mouth reflex, more adaptive movement develops as control of the nonprimary motor cortices over the reflex mechanism in the reticular formation increases. Soon it evolves into the voluntary eye-hand-mouth coordination necessary for food intake as the control of the prefrontal cortex over the nonprimary motor cortices becomes predominant.

The grasp reflex and moro reflex in infants: hierarchy of primitive reflex responses.

The plantar grasp reflex is of great clinical significance, especially in terms of the detection of spasticity. The palmar grasp reflex also has diagnostic significance. This grasp reflex of the hands and feet is mediated by a spinal reflex mechanism, which appears to be under the regulatory control of nonprimary motor areas through the spinal interneurons. This reflex in human infants can be regarded as a rudiment of phylogenetic function. The absence of the Moro reflex during the neonatal period and early infancy is highly diagnostic, indicating a variety of compromised conditions. The center of the reflex is probably in the lower region of the pons to the medulla. The phylogenetic meaning of the reflex remains unclear. However, the hierarchical interrelation among these primitive reflexes seems to be essential for the arboreal life of monkey newborns, and the possible role of the Moro reflex in these newborns was discussed in relation to the interrelationship.

Neural mechanism and clinical significance of the plantar grasp reflex in infants.

The plantar grasp reflex can be elicited in all normal infants from 25 weeks of postconceptional age until the end of 6 months of corrected age according to the expected birth date. This reflex in human infants can be regarded as a rudiment of responses that were once essential for ape infants in arboreal life. The spinal center for this reflex is probably located at the L(5)-S(2) levels, which, however, are controlled by higher brain structures. Nonprimary motor areas may exert regulatory control of the spinal reflex mechanism through interneurons. In infants, this reflex can be elicited as the result of insufficient control of the spinal mechanism by the immature brain. In adults, lesions in nonprimary motor areas may cause a release of inhibitory control by spinal interneurons, leading to a reappearance of the reflex. The plantar grasp reflex in infants is of high clinical significance. A negative or diminished reflex during early infancy is often a sensitive indicator of spasticity. Infants with athetoid type cerebral palsy exhibit an extremely strong retention of the reflex, and infants with mental retardation also exhibit a tendency toward prolonged retention of the reflex.

Neurodevelopmental outcome in children with intraventricular hemorrhage.

To clarify the neurodevelopmental outcome in children with intraventricular hemorrhage, a follow-up study was performed for a consecutive group of 335 subjects in one tertiary center born between 1981 and 1999. Their mean gestation and birth weight were 28.1 weeks and 1162.2 gm, respectively. The follow-up period ranged from 3 to 20 years (mean: 7.5 years). The neurodevelopmental outcomes were normal in 188 (56.1%), cerebral palsy in 75 (22.4%), mental retardation in 34 (10.2%), and borderline intelligence in 38 (11.3%). There were statistically significant differences in the outcomes among the groups with different grades of intraventricular hemorrhage. Approximately 70% of the children with intraventricular hemorrhage grade 1 were normal, whereas only 15.4% of the children with intraventricular hemorrhage grade 4 were normal. Cerebral palsy was associated with as high as 71.2% in the patients with intraventricular hemorrhage grade 4. The overall incidence of epilepsy was 39/335 (11.6%). This study has not demonstrated clear improvement of the outcome in children with intraventricular hemorrhage between the 1980s and 1990s.

Neurodevelopmental outcome in children with posthemorrhagic hydrocephalus.

To determine the factors affecting the neurodevelopmental outcome in children with posthemorrhagic hydrocephalus, 78 children with intraventricular hemorrhage grade 3 or 4 were analyzed concerning the outcome in relation to the grade of intraventricular hemorrhage and intervention (surgical, medical, or no intervention) by means of a follow-up study. The mean age of the subjects at the last follow-up was 9.8 years. In children with intraventricular hemorrhage grade 4 with parenchymal hemorrhage, the outcomes in the group not requiring intervention were better than those in the groups requiring intervention, whereas in children with intraventricular hemorrhage grade 3 without parenchymal hemorrhage, there were no differences in the outcomes among the three groups with and without intervention. For the subjects who had undergone the same intervention, the outcomes in children with intraventricular hemorrhage grade 4 were worse than those in children with intraventricular hemorrhage grade 3. The outcomes in the children with surgical intervention only correlated with the grade of intraventricular hemorrhage. From these findings, we concluded that the outcomes in children with posthemorrhagic hydrocephalus were far more affected by the existence or extent of parenchymal hemorrhage than by the hydrocephalic process, which was suggested to be effectively controlled by the intervention.

Quantitative follow-up analysis by computed tomographic imaging in neonatal hydrocephalus.

We sought a simple and accurate method to monitor neonatal hydrocephalic infants using standard computed tomographic scans. Volume measurements were made by means of pixel counting using a personal computer and a drawing device, as a graphic tablet system, over computed tomographic scans of six infants with neonatal hydrocephalus and four age-matched control infants. The mean value (763.9 +/- 83.3 cm(3)) of the volume of the cranium in the hydrocephalic group was two times higher than that in the age-matched control infants (360.4 +/- 41.4 cm(3)), P < 0.00001. Sequential changes of the ventricular/intracranial volume ratio steadily decreased after cerebrospinal fluid diversion by means of a "two-step procedure" as early in postnatal life as feasible. The mean value (0.67 +/- 0.12) of the lateral ventricle/intracranial volume ratio at birth improved to 12 months of age (0.26 +/- 0.14), P < 0.05. This study has documented, by means of quantitative analysis of serial scans, a statistically significant increase in the neonatal hydrocephalic brain volume after cerebrospinal fluid shunting.

Neurodevelopmental outcome in children with fetal hydrocephalus.

Thirty-eight children with fetal hydrocephalus treated surgically during the neonatal period were analyzed concerning their neurodevelopmental outcome by means of a follow-up study. The mean gestation at diagnosis was 31.1 weeks, and the mean postconceptual age at the first operation was 36.3 weeks. The ages of the patients at the last follow-up ranged from 3.8 to 11.8 years (mean = 7.4 years of age). During the follow-up period, they underwent neurologic examinations and were also evaluated to determine the developmental quotient or intelligence quotient. The relationships between age at diagnosis or the first operation for hydrocephalus and neurodevelopmental outcome, and between the lateral ventricular width/hemispheral width ratio at diagnosis and age at diagnosis or the first operation, and neurodevelopmental outcome were statistically evaluated. The neurodevelopmental outcome in the patients was normal in three patients, borderline intelligence in one patient, mental retardation in seven patients, and motor disturbance in 27 patients (five of whom were intellectually normal). The etiology was a major determinant of the outcome in the children with early postnatal surgical treatment of fetal hydrocephalus. Furthermore, an early onset and a high lateral ventricular width/hemispheral width ratio at diagnosis of hydrocephalus were significantly correlated with a poor intellectual outcome.

[Disclosure of a diagnosis of childhood autism and parents' acceptance of the disability].

Mothers of 14 children (10 boys, 4 girls) with childhood autism answered the self-report questionnaire regarding the disclosure of a diagnosis of autism and their acceptance of the disability. The children's mean age at the study was 8.6 years, and their ages at the time of the disclosure and acceptance were 4.0 and 5.2 years, respectively. The age at acceptance exhibited a statistically significant positive correlation with the age of disclosure indicating that early disclosure was related to early acceptance. The results obtained in the questionnaire suggested that the increased understanding of autistic behavior, the accumulated experience as to how to communicate with their own child and the existence of a self-care group to support the parents were important factors for the acceptance of the disability. The significance of the professionals' sympathetic manner at the time of disclosure, full explanation of the disability, instruction as to how to cope the disability and providing the information on social resources available in the local district was also discussed in relation to the acceptance of the disability.