The influence of head position and head position change on spontaneous body posture and motility in full-term AGA and SGA newborn infants.

No consensus exists concerning the influence of head position and head position change on body posture and motility. Especially the existence of an asymmetric tonic neck reflex (ATNR) in full-term newborns is an issue of discussion. Three-hour video recordings were made of 15 full-term appropriate for gestational age (AGA) and 15 full-term small for gestational age (SGA) infants between the third and eight postnatal day. During a playback of the video recording head position, head position change and several movement patterns of the four limbs were fed into a computer using an event-detecting program. Furthermore, spontaneous head turnings were selected and body posture just before, immediately at and 1 min after the head turning were sketched. The data were analyzed concerning: (1) influence of head position on symmetry of movement of the four limbs; (2) the existence of an ATNR and ATNR-related patterns. In both AGA and SGA infants all movement patterns except hand-face and hand-mouth contact showed a symmetrical distribution, independent of head position. Furthermore, the occurrence of an ATNR following a spontaneous head turning in both AGA and SGA infants was rare. From our results it may be concluded that the ATNR is rare in full-term AGA and SGA newborns. Furthermore, this study demonstrates that head position is not a major factor influencing quantitative aspects of spontaneous motor behaviour. The results are of clinical importance as they imply that in the examination of the neurological condition of the full-term newborn infant by means of observation of spontaneous posture and motility, head position is not of major importance.

Quality of spontaneous general movements in full-term small for gestational age and appropriate for gestational age newborn infants.

Quality of spontaneous movements was studied in 15 healthy full-term appropriate for gestational age (AGA) and in 15 full-term small-for gestational age (SGA) newborn infants. All general movements with a minimal duration of 20 seconds were judged on different aspects of movement quality. From the general movements in each group (AGA: n = 106; SGA: n = 187), dominant patterns were isolated. In the AGA Group 3 dominant patterns of general movements were present. In the SGA Group 5 dominant patterns of general movements were found. Three of those were identical to the movement patterns in the AGA group, the remaining two patterns were unique for the SGA infants. Our results indicate that the three different types of general movements which constitute the major part of the normal repertoire of healthy full-term infants can be used as a reference for normal spontaneous motor behaviour. The two different types of general movements in the SGA infants might be used to discriminate between healthy and neurologically suspect newborn infants. The difference in movement pattern between AGA and SGA infants might be explained by the effect of intrauterine malnutrition on CNS development.

Postural behaviour of term SGA and AGA newborn infants.

The authors studied the body posture at rest of 15 healthy term infants with birthweights appropriate for gestational age (AGA) and 15 infants who were small for gestational age (SGA). In both groups, there was wide inter-individual variability in postural behaviour. Apart from a preference for a position with all limbs in abduction between 1 and 90 degrees, independent of the degree of flexion or extension and internal/external rotation, no dominant preference posture could be seen for either group. The SGA infants showed a more flexed position of the arms, compared with the AGA group. One of the factors contributing to this difference might be the influence of intra-uterine malnutrition on the development of the central nervous system.

State profile in low-risk pre-term infants: a longitudinal study of 7 infants from 32-36 weeks of postmenstrual age.

Spontaneous motor behaviour was longitudinally studied in 7 low-risk preterm infants. The object of this study was to determine whether or not certain recognizable behavioural states exist between 32 and 36 weeks postmenstrual age (PMA), in order to have a well defined recognizable pattern of behaviour during which the preterm infant can be clinically examined. The criteria used to define a behavioural state were: eyes open/closed; crying present/absent; gross body movements present/absent; and respiration regular/irregular. A total of 35 videotapes were made (total time, 99 hours and 25 minutes). For analyzing the data, one second and three-minute windows were used. Our data provide convincing evidence that spontaneous behaviour of preterm infants of 32-36 weeks of PMA can be classified into behavioural states. The variables gross body movements and respiration, are not independent ones. The observed states can be used as a defined clinical condition during which the preterm infants can be clinically examined.

Posture of low-risk preterm infants between 32 and 36 weeks postmenstrual age.

The supine posture of 15 low-risk preterm infants was studied to establish whether they have a preferred posture and, if so, whether it changes with age. No over-all preferred posture was found. Almost always one posture was adopted most frequently, but often a great variety of other postures were adopted almost as frequently. There was no correlation between postmenstrual age and preferred posture, the number of different postures, or the duration of longest uninterrupted posture.

Posture during head turning in pre-term infants: a longitudinal study of 15 low-risk infants of 32-36 weeks of conceptional age.

As part of a longitudinal study of spontaneous behaviour from 32-36 weeks of conceptional age, body posture was studied during spontaneous head movements in 15 low-risk pre-term infants. At the moment of an active head position in the midline, the most frequently observed posture was a symmetrical one in which the arms were fully flexed and the legs partly extended. With regard to the arm position no clearly developmental trend was noted. With regard to the leg position an increase of the partly flexed position of the limbs related to conceptional age was found. The observed postures during activity in our study showed a cephalocaudal acquisition of flexor tone. A symmetrical posture, when the head is in the midline, may be a sign of normality in pre-term infants.

Influence of head position and head position-change on body posture in pre-term infants (A.T.N.R.).

Although body posture in pre-term infants is generally studied to describe developmental aspects, no consensus exists in literature about the influence of head position and head position change upon body posture in pre-term infants. In a weekly assessed longitudinal study of 15 healthy pre-term infants we extensively observed and analysed the flexion and extension patterns of the limbs in relation to a "spontaneous" head position turning from 32 to 36 weeks of conceptional age. A significant flexion/extension pattern was only observed with respect to the leg: turning of the head induced extension of the chin leg and flexion of the other leg. This pattern persisted during the total 3 hours observation sessions, occurred at every age and in all states, but rapidly disappeared within maximal 20 seconds after the head-turning. No consequent significant pattern was observed with respect to the other limbs or the various other combinations of limb posture changes analysed. An Asymmetric Tonic Neck Reflex was seen after only 3 percent of the head position changes.

Head position in low-risk premature infants. Impact of nursing routines.

Head position preference in 15 low-risk pre-term infants studied in relation to conceptional age and nursing routines. A head position preference to the right is evident with respect to the head position imposed by the nurse. The observed spontaneous head position preference might be ascribed to the influence of the foregoing imposed head position, the influence of which diminishes with increasing observation time. After several spontaneous head turnings the low-risk pre-term infants show no head position preference anymore.

Ambulatory sleep-wake polygraphy in narcolepsy.

We have presented an ambulatory monitoring and off-line data analysis system for sleep-wake polygraphy and have illustrated its use for the diagnosis of narcolepsy. The advantages over conventional polysomnography have been discussed.

An application of mathematical models in posturography.

The measurement of the horizontal displacements (HD) of the centre of mass of the human body when standing still, is often performed by means of a platform. The resulting measured HD as a function of time, both in the left-right or sinister-dexter and the posterior-anterior direction, are known as stabilograms. Such stabilograms are being more widely used to obtain the so called measured statokinesigram, similar to a Lissajous-figure, by eliminating time from the sinister-dexter stabilogram and the posterior-anterior stabilogram. It is shown that in using mathematical models of the standing person to obtained the stabilograms, the resulting statokinesigram is very different from the measured statokinesigram. It is also shown that the quantity line-integral calculated from a statokinesigram is much smaller when determined from a statokinesigram corrected by means of the mathematical models.

Human cerebral potentials evoked by moving dynamic random dot stereograms.

In 11 normal healthy human subjects an evoked potential was elicited by moving dynamic random dot stereograms. The random dots were generated by a minicomputer. An average of each of 8 EEG channels of the subjects tested was made. The maximum of the cerebral evoked potentials thus found was localized in the central and parietal region. No response earlier than 130--150 msec after the stimulus could be proved. The influence of fixation, the number of dots provided, an interocular interstimulus interval in the presentation of the dots, and lense accommodation movements on the evoked stereoptic potentials was investigated and discussed. An interocular interstimulus interval (left eye leading) in the presentation of the dots caused an increase in latency of the response much longer than the imposed interstimulus interval itself. It was shown that no accommodation was needed to perceive the depth impression, and to evoke the cerebral response with random dot stereograms. There are indications of an asymmetry between the two hemispheres in the handling of depth perception after 250 msec. The potential distribution of the evoked potentials strongly suggests that they are not generated in the occipital region.