Fetal handedness and head position preference: a developmental study

Hand-head contacts were observed by means of serial ultrasound recordings in 10 healthy fetuses from 12 to 38 weeks of gestational age. Contacts were distinguished as being unimanual or bimanual, and if unimanual, whether they were made with the right or left hand. Both types of contact and ones made unimanually with the right or left hand were identified at each age as to whether they were associated with a preferential head position. A strong unimanual bias was evident at each age except for Week 36. At this age, there was a bimanual bias. Unimanual contacts did not develop a lateralized preference, and neither type of contact established a stable relationship with head position. Furthermore, there was no evidence to support the suggestion that hand contact and head position codevelop to form a preferred ipsilateral synergy. Findings are discussed relative to contradictory evidence from other fetal and neonatal studies.

Muscle power in "high-risk" preterm infants at 12 and 24 weeks corrected age: a measure for early detection

A group of 72 "high-risk" preterm infants was studied at the corrected ages of 12 and 24 wk. Only infants with a high risk for developmental deviance with gestational ages below 32 wk and/or birthweights of less than 1500 g were included in the study. In addition, the infants were categorized according to their medical history, as confirmed by the "Neonatal Medical Index" (NMI I to V), with category I describing infants with few medical problems and V characterizing those with the most serious complications. In this study we included only "high-risk" infants as categorized in NMI III to V, since infants with a "low risk" have been described earlier. Apart from the standard paediatric follow-up, an age-adequate neurological assessment was made, with special emphasis on the relationship between active and passive muscle power. When development is optimal, these two components of muscle power should be in balance in order to create a stable posture and fluent motility. We compared muscle power at the corrected ages of 12 and 24 wk to determine whether the method employed to assess muscle power could enhance early detection of deviant development. At 12 wk of age, only 5 infants showed overall optimal muscle power, while at 24 wk this figure had increased to 27. Significantly more infants in NMI III had optimal outcomes at 24 wk of age. When muscle power in the different parts of the body was studied separately at 24 wk, outcomes in shoulders and trunk still showed significant discrepancies in all NMI groups. At this age, fewer asymmetries were found compared to outcomes at 12 wk.

CONCLUSION

Our method of assessing muscle power is useful in detecting preterm infants at risk for pathological development.

Effect of ruminal protein degradability on growth and N metabolism in growing beef steers

The objective of two experiments was to correlate plasma levels of urea N (PUN) and the percentage of urine N in the form of urea (UUN) to weight gain in response to different dietary protein regimens for growing Angus steers. In Exp. 1, 60 steers (302 kg BW) were assigned to various levels of dietary N (control plus supplemental N to provide from 100 to 400 g more crude protein daily) within two sources of supplemental N (soybean meal [SBM] or a mixture of two parts corn gluten meal:one part blood meal [CGM:BM]). In Exp. 2, 27 steers (229 kg BW) were fed two levels of SBM, and half of the steers received growth-promoting implants. Steers were housed in groups of 12 and fed individually for 84 d in both experiments. Corn silage was fed at a restricted rate to minimize orts. Jugular blood and urine samples were collected during the experiments. In Exp. 1, maximal ADG of steers fed SBM (1.0 kg) was reached with 671 g/d total crude protein, or 531 g/d metabolizable protein. Maximal ADG of steers fed CGM:BM (0.91 kg) was reached with 589 g/d total crude protein, or 539 g/d metabolizable protein. The DMI was higher (P < 0.07) for steers fed SBM (6.37 kg/d) than for steers fed CGM:BM (6.14 kg/d). Increasing ruminal escape protein from 36% (SBM) to 65% (CGM:BM) of CP decreased (P < 0.05) endogenous production of urea, as evidenced by lower concentrations of urea in blood and lower UUN. In Exp. 2, increasing supplemental protein from 100 to 200 g/d increased (P < 0.05) ADG and PUN. Implants lowered (P < 0.05) UUN, particularly at the higher level of supplemental protein. Protein supplementation of growing steers can be managed to maintain acceptable ADG yet decrease excretion of urea in the urine.

Development of spontaneous leg movements in infants with and without periventricular leukomalacia

The main question asked in the present study was whether support could be found for the notion that supraspinal influences on the generation of spontaneous kicking movements become increasingly apparent in the first half-year after birth. In comparing groups of infants with and without damage in tracts connected with the cortex surrounding the central sulcus, such support would consist of the finding that similar patterns of spontaneous kicking are observed early in development, whereas differences between groups should occur with increasing age. Using 3-D registrations, the spontaneous kicking movements of 19 infants with differing degrees of periventricular, lobar, and subcortical leukomalacia based on white matter (WM) abnormalities on ultrasound were compared to those of 10 healthy control infants at 6, 12, 18, and 26 weeks of corrected age. Magnetic resonance imaging recordings were used to identify the location and severity of the brain lesions. Infants with extensive lesions in the periventricular and lobar WM with or without diffuse lesions in the subcortical WM showed a decreased variability on some spatial and temporal parameters of kicks. More importantly, these infants showed a different developmental course for intralimb couplings when compared to the other infants; they were unable to dissociate tight intralimb couplings at 18 and 26 weeks. As all of these infants had substantial damage of the corticospinal tracts, these findings suggest that these tracts are involved in the regulation of intralimb joint dissociations between 4 and 6 months of age. However, caution is needed as areas outside those in which the corticospinal tracts are located could be damaged as well and most of the infants with moderate to severe lesions in the corticospinal tract had additional psychomotor problems. For interlimb couplings and most of the spatial and temporal parameters of kicks, no differences were found between groups. This strengthens the claim that inter- and intralimb couplings are organized in fundamentally different ways.

Motor asymmetries in the human newborn are state dependent, but independent of position in space

Human newborns have a preference for turning and maintaining the head to one side of the body. Most studies confirm a right-sided preference in supine. Few have addressed the state dependency of this lateral bias, and even fewer have examined whether it is also expressed in the semi-upright position. We investigated whether it varies as a function of behavioural state and position in space. Kinematic recordings of head movements were made with the newborn secured on a platform in the supine or semi-upright position, which alleviated biomechanical and postural constraints imposed by gravity. Newborns differed as to whether they had a vertex, Caesarean or breech delivery. The majority of infants maintained a right-sided preference in both positions, but it was strongly mediated by state. Delivery type did not account for any lateral bias. These findings provide convincing evidence that a lateral bias in movement and positioning of the head are reflections of active neural processes rooted in the regulation of state.

Vision of the hand and environmental context in human prehension

Previous findings on the role of visual contact with the hand in the control of reaching and grasping have been contradictory. Some studies have shown that such contact is largely irrelevant, while more recent ones have emphasised its importance. In contrast, information arising from the surrounding environment has received relatively little attention in the study of prehensile actions. In order to identify the roles of both sources of information, we made kinematic comparisons between three conditions. In the first, reaching was performed in a dimly lit room and compared with a second condition in which reaches in the dark, but with the thumb and first finger illuminated, were made to a luminous object. This contrast allows the effects of environmental context to be identified. A comparison between the second and a third condition, in which both vision of the hand and the environment was removed, but the object was still visually available, enabled the assessment of how and when vision of the hand plays a role. Removing environmental cues had effects both early and late in the reach, while vision of the hand was only crucial in the period after peak deceleration. In addition, removal of both sources of information resulted in larger grip apertures. Differences and similarities between our findings and those of other studies are discussed, as is the ongoing debate about the relative importance of visual feedback of the hand in the control and co-ordination of prehensile actions. We conclude with suggestions for further research based on the set-up used in the present study.

Prenatal active or passive tobacco smoke exposure and the risk of preterm delivery or low birth weight

We examined the association of exposure to environmental tobacco smoke with birth weight and gestational age in a large, prospective study. We also compared these endpoints between infants of active maternal smokers and those of non-smoking, non-ETS exposed women. Pregnant women were interviewed by telephone during the first trimester, and pregnancy outcome was determined for 99%. Among the 4,454 singleton live births that could be linked to their birth certificate, we confirmed increased risks of low birth weight and small for gestational age with heavier maternal smoking (> 10 cigarettes/day), as well as noting an increased risk for "very preterm" birth (< 35 weeks). These associations were generally stronger among infants of older (> or = 30 years) than those of younger mothers, as well as among non-whites. High environmental tobacco smoke exposure (> or = 7 hours/day in non-smokers) was moderately associated with low birth weight (adjusted odds ratio (AOR) 1.8, 95% confidence limits (95% CL) = 0.82, 4.1), preterm birth (AOR 1.6, 95% CL = 0.87, 2.9), and most strongly with very preterm birth (AOR 2.4, 95% CL = 1.0, 5.3). These associations were generally greater among non-whites than whites. The data support earlier studies suggesting that prenatal environmental tobacco smoke exposure, in addition to maternal smoking, affects infant health.

Reducing nosocomial pressure ulcers in an acute care facility

In 1996, a nursing committee at an acute care facility organized the first pressure ulcer point prevalence survey for that hospital. In 1996, hospital-acquired pressure ulcers were 90 percent of the predicted prevalence rate; in 1997, the rate dropped to 59 percent of the predicted prevalence and in 1998, to 53 percent of the predicted prevalence. The severity index decreased markedly from 291 (1996) to 98 (1997) then to 62 (1998). These improvements are attributed to the purposeful addition of multidimensional interventions, including best practices and research-based protocols, to prevent and treat nosocomial pressure ulcers.

Spontaneous kicking behavior in infants: age-related effects of unilateral weighting

The age-related effects of unilateral weighting on spontaneously generated kicks in 18 healthy, full-term infants were investigated. The main question was whether infants during the first half-year after birth reveal changes in how they adjust to unilateral weighting. At 6 weeks, infants reduced the frequency of the weighted leg and increased that of the unweighted leg whereas at 12 weeks the frequency of kicking increased in both legs. At both ages, unilateral weighting also resulted in differences on a number of kinematic parameters. By 18 and 26 weeks, such frequency and kinematic effects were no longer present. With regard to interlimb couplings, a clear pattern of bilateral coordination was only present at 26 weeks; these results suggest that the effects of unilateral weighting are not directly related to the tightness of interlimb couplings. The implications of these age-related differences for understanding developmental changes in the control of leg movements are discussed. It is suggested that the infants' improved ability to act in a task-specific manner as well as nonlinear changes in the musculo-skeletal system and fine-tuning processes at a neural level might be factors of importance.

The coordination of two-effector actions: spoon-feeding and intermanual prehension

The aim of this study was to assess whether kinematic characteristics of unimanual (one-effector) prehension movements can also be found in tasks where the transport and grasp components are distributed across separate effectors. Expt 1 compared prehension with spoon-feeding and showed that a number of kinematic landmarks, such as time to peak aperture, were similar. An unexpected difference between the tasks was that the onsets of the transport and grasp components in the two-effector task were not always synchronized. To control for a number of differences between the tasks used in Expt 1, such as the role of haptic and visual information, Expt 2 compared unimanual with intermanual prehension, which involved passing an object from one hand to the other. The results were consistent with those found in Expt 1. In particular, time to peak aperture was similar over the different tasks, despite a lack of consistent coupling between the components at movement onset. We conclude that the one- and two-effector tasks pose largely the same task constraints and are coordinated in a similar way. Intermanual prehension tasks thus provide a useful experimental tool for manipulations that are difficult or impossible to perform with unimanual reaching and grasping.

Characterisation of the 5-HT receptor binding profile of eletriptan and kinetics of [3H]eletriptan binding at human 5-HT1B and 5-HT1D receptors

The affinity of eletriptan ((R)-3-(1-methyl-2-pyrrolidinylmethyl)-5-[2-(phenylsulphonyl )ethyl]-1H-indole) for a range of 5-HT receptors was compared to values obtained for other 5-HT1B/1D receptor agonists known to be effective in the treatment of migraine. Eletriptan, like sumatriptan, zolmitriptan, naratriptan and rizatriptan had highest affinity for the human 5-HT1B, 5-HT1D and putative 5-ht1f receptor. Kinetic studies comparing the binding of [3H]eletriptan and [3H]sumatriptan to the human recombinant 5-HT1B and 5-HT1D receptors expressed in HeLa cells revealed that both radioligands bound with high specificity (>90%) and reached equilibrium within 10-15 min. However, [3H]eletriptan had over 6-fold higher affinity than [3H]sumatriptan at the 5-HT1D receptor (K(D)): 0.92 and 6.58 nM, respectively) and over 3-fold higher affinity than [3H]sumatriptan at the 5-HT1B receptor (K(D): 3.14 and 11.07 nM, respectively). Association and dissociation rates for both radioligands could only be accurately determined at the 5-HT1D receptor and then only at 4 degrees C. At this temperature, [3H]eletriptan had a significantly (P<0.05) faster association rate (K(on) 0.249 min(-1) nM(-1)) than [3H]sumatriptan (K(on) 0.024 min(-1) nM(-1)) and a significantly (P<0.05) slower off-rate (K(off) 0.027 min(-1) compared to 0.037 min(-1) for [3H]sumatriptan). These data indicate that eletriptan is a potent ligand at the human 5-HT1B, 5-HT1D, and 5-ht1f receptors and are consistent with its potent vasoconstrictor activity and use as a drug for the acute treatment of migraine headache.

Evaluation of four maternal smoking questions

OBJECTIVE

The authors evaluated four questions about maternal smoking during pregnancy for use on birth certificates.

METHODS

Question 1 (yes/no format) and Question 2 (trimester-specific design) were tested among 1171 women who delivered at two Kaiser Permanente medical centers in northern California. Responses to Questions 1 and 2 were compared with smoking information provided by participants in telephone interviews conducted during pregnancy. Question 3 (multiple choice format) and Question 4 (month- and grouped month-specific design) were tested among 900 women who enrolled in a statewide prenatal screening program and who delivered in 20 hospitals in four Central Valley counties. Responses to Questions 3 and 4 were compared with mid-pregnancy serum cotinine levels. The authors evaluated the four questions in terms of conciseness, response rate, data accuracy, and type of data requested.

RESULTS

Questions 1 and 2 were the most concise. Response rates could not be calculated for Questions 1 and 2. Response rates were 86.0% for Question 3 and 74.2% for Question 4. Sensitivity was 47.3% for Question 1, 62.1% for Question 2, 83.8% for Question 3, and 86.7% for Question 4. The types of data requested by Questions 2 and 4 seem to best satisfy the needs of the broad audience of birth certificate users.

CONCLUSIONS

No single question was clearly superior. The authors propose a combination of Questions 2 and 4, which asks about average number of cigarettes smoked per day in the three months before pregnancy and in each trimester of pregnancy.

Evidence for an association between environmental tobacco smoke exposure and birthweight: a meta-analysis and new data

Because of the strong association of active smoking with fetal growth retardation, increasing interest has focused on whether there is also an association with exposure to environmental tobacco smoke (ETS). We examined this issue in a retrospective study and by conducting a review of the literature and data pooling. In our study, nonsmoking women with singleton livebirths born in 1986-87 (n = 992) provided information on exposure to ETS for 1 h or more per day and paternal smoking. The risk of low birthweight (LBW, < 2500 g) was not increased in infants of ETS-exposed women, but there was a somewhat increased risk for LBW at term (adjusted odds ratio [OR] 1.8, 95% confidence interval [CI] 0.6, 4.8) and small-for-gestational-age (< 10th percentile of weight; OR = 1.4, 95% CI = 0.8, 2.5). These results were in the range of 16 other studies in the literature that had odds ratios from 1.0 to 2.2. A weighted average of the results of all studies on LBW at term or small-for-gestational-age yielded a pooled estimate of 1.2 [95% CI = 1.1, 1.3] in nonsmoking women. The pooled estimate of mean birthweight indicated a decrement of 28 g with ETS exposure of nonsmoking women [95% CI = -41, -16], with a greater decrement (about 40 g) seen among more homogeneous studies.

Lateral biases in head turning and the Moro response in the human newborn: are they both vestibular in origin?

Head turning after release from the midline and the Moro response to a full-body drop in 15 full-term newborns lying supine on a custom-built platform was studied. While the lateral bias for head turning was not as pronounced as for the Moro response, it was still assumed in the ratio of 2 (right):1 (left) as predicted by Previc (1991). Onset latency and time-to-peak acceleration were both significantly shorter in the right arm during the initial phase of the Moro response. For both measures, this right arm bias persisted over four consecutive elicitations in most infants. Vaginally delivered infants and those born by Caesarean section did not differ in terms of head preference and the two measures of arm advantage. Our main finding was that infants with a right-sided head preference had a consistently shorter onset latency for the right arm. We interpret this association as stemming from a common labyrinthine asymmetry that involves different vestibulospinal pathways for the neck and arm muscles. In general, our findings are discussed in the context of Previc's (1991) left-otolithic dominance hypothesis and Grattan, De Vos, Levy, and McClintock's (1992) model of newborn functional asymmetries.

Muscle power and medical history in high risk preterm infants at 3 months of corrected age

A group of 73 "high risk" preterm infants was studied at the corrected age of 12 weeks. The infants were categorized according to their medical history in 5 classes conform with the "Neonatal Medical Index" (NMI). Only infants with high-risk for developmental discrepancies with a score of NMI > or = III were included in the study. Apart from pediatric follow-up and an age-adequate neurological examination, special emphasis was put on measuring a specific feature in the development of preterm infants: the relationship between active muscle power and passive tone. These two components of muscle power should be in balance with each other to create stable posture and fluent motility and later co-ordination. Discrepancy between active and passive muscle tone was found in all NMI groups studied and was most outspoken in the legs. Infants in NMI IV and V showed a significantly higher incidence of increased passive tone than the infants in NMI III. When the different regions of the body were studied separately, the infants in NMI IV and V showed significantly increased passive tone in the trunk and shoulders (p 0.009) compared to infants in NMI III, which may constitute an alarm signal of deviant development. The main aim of the study was to provide a clinical method for early detection, subtle enough to select infants most at risk for later functional and neurological problems.

Repeated low-level formaldehyde exposure produces cross-sensitization to cocaine: possible relevance to chemical sensitivity in humans

Sensitivity to chemicals in humans has been proposed to be an acquired disorder in which individuals become increasingly sensitive to chemicals in the environment. A possible link between the manifestation of psychiatric symptoms in individuals claiming sensitivity to chemicals was investigated based on a leading hypothesis put forth by Bell and co-workers (1992) to explain the amplification of symptoms after chemical exposure. The hypothesis is that chemical sensitivities may be akin to sensitization observed in rodents after repeated psychostimulants. Repeated exposure to psychostimulants enhances behavioral activity and the underlying neurochemical responses in specific limbic pathways; a similar sensitization of limbic pathways has been proposed to occur in individuals who become sensitive to chemicals. To test this hypothesis, female Sprague-Dawley rats were exposed to either air or formaldehyde (Form) for 1 h/day for 7 days or 20 days (5 days/week x 4 weeks). Two to 4 days after the last exposure, rats were given a cocaine challenge (= early withdrawal) followed by an additional cocaine challenge 4-6 weeks later (= late withdrawal). No differences in cocaine-induced locomotor activity were noted between groups after 7 days of exposure. However, after 20 days of exposure to Form, vertical activity was significantly elevated at both early and late withdrawal times. These studies demonstrate that behavioral sensitization occurs after long-term, but not short-term, low-level exposure to Form, and lends support to the limbic system sensitization hypothesis of sensitivity to chemicals in humans.

Prenatal development of arm posture

Fetal arm posture was studied longitudinally in 10 uncomplicated pregnancies using real-time ultrasound. Observation were performed at four weekly intervals from 12 to 36 weeks, and at 38 weeks. The percentage of assessments with optimal visualization of elbow, wrist and fingers was 84% at 12 weeks and more than 90% thereafter (range 92-98%). There was a clear developmental trend towards increased flexion. Flexion of the elbow occurred frequently from 12 weeks onwards with an increased incidence at 16 weeks, that in the fingers from 20 weeks onwards and from 28 weeks to term age in the wrist. All three trends were statistically significant. There was considerable intra-individual consistency in terms of the ages at which flexion increased. In fact the increase of flexion occurred one session later in only 6/30 registrations. The combined data of the elbow, wrist and fingers revealed preferential arm posture at 12 weeks with the elbow flexed and the wrist and fingers extended. From 16 to 28 weeks, the predominant posture consisted of elbow flexion, wrist extension and finger flexion and complete flexion thereafter. The development of fetal arm posture does not comply with a proximo-distal trend in that there was first an increase in flexion at the elbow, followed by the fingers and finally the wrist. The implications of our findings for understanding the prenatal development of the central nervous system and subsequent postural adjustments to extrauterine life are discussed.

Adrenal cortical carcinoma associated with a splenic vein tumor thrombus

A unique case is reported of a left adrenal cortical carcinoma with a splenic vein tumor thrombus. En bloc radical nephroadrenalectomy, distal pancreatectomy, splenectomy and splenic vein tumor thrombectomy were performed. Reconstruction of the proximal portal vein was required, incorporating a segment of the left renal vein (harvested from the surgical specimen) as a free interposition graft, bridging the defect between the superior mesenteric vein and portal vein. To our knowledge, this is the first reported case of an adrenal cortical carcinoma associated with a splenic vein tumor thrombus. In addition, the described technique used to reconstruct the proximal portion of the portal vein has not been previously reported.

Evidence for a phase transition in the early development of prehension

A longitudinal study was conducted to examine the hypothesis that the development of prehension during the first 5 months of life is characterized by the presence of a discontinuous phase transition. Ten infants were observed weekly from 8 to 24 weeks of age. Video recordings were made of movements toward an attractive object which were classified according to two behavioral categories: reaching without grasping and reaching with grasping. The time evolution of the relative incidence of these behavioral categories was analyzed statistically. Evidence was found for a sudden jump from a (developmental) state in which reaching without grasping is predominant to a state in which reaching with grasping is predominant. Evidence was also found for bimodality, inaccessibility, and anomalous variance. In combination, these findings support the hypothesis that the investigated behavioral change constitutes a discontinuous phase transition. The behavioral change in question occurred at the moment in developmental time at which the attractor strength of reaching for objects as such relative to that of other behavioral activities appeared to be increased.

A prospective study of spontaneous abortion: relation to amount and source of drinking water consumed in early pregnancy

In 1992, we published four retrospective studies, conducted primarily within a single California county, which found higher spontaneous abortion rates among women who drank more tapwater than bottled water in early pregnancy. The current prospective study extends that investigation to other water systems. Pregnant women from three regions in California were interviewed during their first trimester. Multivariate analyses modeled the amount and type of water consumed at 8 weeks' gestation in each region in relation to spontaneous abortion rate. In Region I, which was within the previous study area, the adjusted odds ratio (OR) comparing high (> or = 6 glasses per day) consumption of cold tapwater with none was 2.17 [95% confidence interval (CI) = 1.22-3.87]. Furthermore, when women with high cold tapwater and no bottled water consumption were compared with those with high bottled water and no cold tapwater consumption, the adjusted odds ratio was 4.58 (95% CI = 1.97-10.64). Conversely, women with high bottled water consumption and no tapwater had a reduced rate of spontaneous abortion compared with those drinking tapwater and no bottled water (adjusted OR = 0.22; 95% CI = 0.09-0.51). Neither tap nor bottled water consumption altered the risk of spontaneous abortion in Regions II and III. Although controlling for age, prior spontaneous abortion, race, gestational age at interview, and weight somewhat strengthened the association in Region I, the distribution of these confounders did not vary appreciably across regions. This study confirms the association between cold tapwater and spontaneous abortion first seen in this county in 1980. If causal, the agent(s) is not ubiquitous but is likely to have been present in Region I for some time.

Trihalomethanes in drinking water and spontaneous abortion

Trihalomethanes (chloroform, bromoform, bromodichloromethane, and chlorodibromomethane) are common contaminants of chlorinated drinking water. Although animal data indicate that these compounds may be reproductive toxicants, little information exists on their relation to spontaneous abortion in humans. We examined exposure to trihalomethanes and spontaneous abortion in a prospective study of 5,144 pregnant women in a prepaid health plan. Seventy-eight drinking water utilities provided concurrent trihalomethane sampling data. We calculated total trihalomethane levels by averaging all measurements taken by the subject's utility during her first trimester. We calculated exposures to individual trihalomethanes in an analogous manner. Women who drank > or = 5 glasses per day of cold tapwater containing > or = 75 micrograms per liter total trihalomethanes had an adjusted odds ratio (OR) of 1.8 for spontaneous abortion [95% confidence interval (CI) = 1.1-3.0]. Of the four individual trihalomethanes, only high bromodichloromethane exposure (consumption of > or = 5 glasses per day of cold tapwater containing > or = 18 micrograms per liter bromodichloromethane) was associated with spontaneous abortion both alone (adjusted OR = 2.0; 95% CI = 1.2-3.5) and after adjustment for the other trihalomethanes (adjusted OR = 3.0; 95% CI = 1.4-6.6).

Head position preference in the human newborn: a new look

Head position preference was studied in 20 awake newborns who differed in terms of delivery and sex. They were placed supine on a custom-built platform to reduce the effects of gravity and asymmetries in trunk posture and skull shape. A global and a specific scoring method were used, the infants being in State 3 (quiet wakefulness) or 4 (active wakefulness, excluding crying). Delivery and sex did not account for differences in head position. The head turned more often to the right and was maintained longer in this position during State 3, regardless of scoring method. The maintenance of the head in midline was comparable in duration to that reported for infants at 2-3 months when using the global scoring method. This suggests that the neural mechanisms responsible for attaining and maintaining a midline position are present at birth, but are not functionally expressed due to a lack of adequate power in the antigravity muscles of the neck.

Locomoting through apertures of different width: a study of children with cerebral palsy

Whether children with cerebral palsy (CP) differ from non-handicapped (NH) children was studied, using body-scaled information about the passability of a doorway-like opening. There were 55 children of whom 23 were NH and 32 had CP, the latter consisting of 12 who could stand and walk unaided (CP-Walk) and 20 confined to a wheelchair (CP-Wheel). All groups were divided into two age ranges (5-8 and 9-13 year) and were tested on two occasions separated by an interval of 12 months. On both occasions, testing involved three consecutive tasks: making perceptual (pre)judgments about the passability of an opening varying in width, actually attempting to locomote through the openings (performance), and another round of (post)judgments. Judgments and performance were expressed in terms of absolute and relative outcomes, the latter differing from the former in accounting for differences in body width relative to aperture width. There were two main findings. Firstly, the younger CP-Walk children were the least able to employ body-scaled information in judging aperture width and the older CP-Wheel and NH the most able. Secondly, when performances in passing through the openings were adjusted for differences in body width, all groups had similar outcomes. This findings lends credence to the notion that when action is used in the service of perception, this is beneficial for the visual-spatial abilities of both NH and CP children. The study concludes by pointing out future directions in this type of research as well as some of the clinical implications of the findings.