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Research Reports |
JW Sparling, PhD, PT, OT, was Associate Professor of Human Movement and Project Director of the Maternal and Child Health Postgraduate Training Grant at the University of North Carolina at Chapel Hill at the time this study was conducted. Address all correspondence to Dr Sparling at 1444 Center Grove Church Rd, Moncure, NC 27559 (USA) (jwspar{at}med.unc.edu)
J Van Tol, PhD, is Research Assistant, Amsterdam, the Netherlands. At the time of this study, she was a Postdoctoral Fellow with Dr Sparling
NC Chescheir, MD, is Associate Professor of Obstetrics, School of Medicine, University of North Carolina at Chapel Hill
Submitted November 10, 1997;
Accepted August 17, 1998
 | Abstract |
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Key Words: Development • Fetus • Movement • Neonate
| Introduction |
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The purpose of this article is to report on an exploration of human fetal and neonatal movement. Our goal was to determine (1) the duration and frequency of specific motor behaviors, (2) changes or trends in the expression of these behaviors during pregnancy, and (3) the manner in which these motor behaviors exist neonatally, as the environment and the child change.
| Background |
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TopAbstractIntroductionBackgroundMethodResultsDiscussionConclusionAppendixReferences |
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Sparling and Wilhelm20 described spontaneous movements in fetuses from 12 to 35 weeks of gestation and recorded the characteristics of hand movement. Many movements appeared to be directed to a body part or the uterine wall. The hands of the fetuses moved with a variety of frequencies and apparent force. Joint ranges of motion changed throughout movements rather than remaining the same, as in floating. These movements suggested primary and secondary circular reactions21 in which a movement is repeated, presumably because it has functional importance to the organism. Sparling and Wilhelm observed, for example, that early in fetal development, quick, progressively larger head flexion movements were repeated, resulting in a "somersault" that enabled the fetus to change position within the uterine cavity. In contrast, during later gestational periods, the fetuses' hands were directed to and manipulated body parts and features of the environment, such as the umbilical cord. Thus, later in pregnancy, the hands exhibited manipulative capability and suggested "intentionality," a term coined by Butterworth and Hopkins22 to describe neonatal hand-to-mouth movement.
Other developmental tendencies in hand movement were noted in early observations20 and are summarized in Table 1. In that study, movements such as thumb in mouth and bilateral leg extension against the uterine wall were considered by the authors as functionally important. The frequently observed leg extension against the uterine wall was believed by the authors to be a possible precursor to later participation in the birthing process. Validation of the importance of this movement has been noted in a similar movement of the chick readying itself for hatching.23 Early movements of the arms appear to assist the fetus in identifying components of its environment. The hands can be observed to cross midline, with the palms "feeling" the uterine wall. The fetus' palms also mold to the occiput, grasp the umbilical cord, and appear to "reach" for the feet. Attributing function to any of these early movements, however, does not imply that the assigned function is preliminary to or necessary for the appearance of a spontaneous behavior.
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Based on the literature and previous studies, we hypothesized that there would be extensive, apparently non-functional hand movements early in the fetal period. After the diminution of quantity of movement at 16 weeks of gestation noted previously,27 which we posit was caused by preprogrammed neuronal cell death,28–30 we would expect to see an increase in more specific movements such as hand to mouth, a movement considered to be functional for the fetus as well as the newborn.22 The increase in these functional movements would suggest some development in motor behavior and an increased level of motor control by the fetus. The decrease in these behaviors might indicate a developmental regression in the behavior.
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Subjects
The women who participated in this study were a convenience sample of low-risk pregnant women attending the University Hospitals' Obstetric Clinic for pregnancy assessment and follow-up. All women except one were Caucasian, and all women except one were married and living with their husbands. We believe that a single woman may be under more stress during her pregnancy and that this stress might affect the fetus and its movement. This was the first pregnancy for 9 of the 21 women. At the start of the study, 8 women had one living child, and 4 women had more than one child. The mean maternal age was 30.6 years (SD=5.1, range=21–40), and the mean paternal age was 31.7 years (SD=4.8, range=19 –39). The 4-Factor Index of Social Status33 was computed by averaging scores on grade level completed and occupation for the mother and father. Maternal education ranged from high-school completion to over 22 years of education (
=14.3, SD=2.6), and mean paternal education was 15.6 years (SD=4.4). Occupations ranged from category 3 (housewife) to category 9 (professional). The mean score of 42.3 (SD=12.1) gave an educational-occupational social status range of 2 to 5 (=3.5) out of a possible 5 categories.
The designation of "low risk" for fetuses was made during the initial obstetric visit based on maternal medical history and health status and was checked at each subsequent visit by the obstetrician and the obstetrical nurse. The sex of the fetuses (12 male, 9 female) and their birth age, birth weight, length, head circumference, and Apgar scores at 1 and 5 minutes were recorded at birth. These data and the follow-up of the fetuses (Tab. 2) by examination of their medical records at a mean age of 12.3 months (SD=5.5, range=4 –19) indicate that we had identified a low-risk sample of pregnant women whose pregnancies were within normal limits and whose infants were functioning within normal limits, according to physician report, within the first year after birth. There were no multiple births.
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were used to obtain the fetal and neonatal data. A super-VHS tape deck and 38.1-cm (15-in) high-resolution monitor were used for viewing the videotapes. Data were input directly to a computer via a software package designed for start-stop and continuous scoring.
Procedure
Each woman was identified by the clinic nurse during her initial clinic visit at 12 weeks. Appointments were made for the first ultrasound imaging at 14 weeks according to maternal estimation of pregnancy duration. Biparietal diameter and femoral length were used to confirm maternal dates. The ultrasound images were taken at 14 weeks (=14.0 weeks, SD=4 days, range=13.0–15.6 weeks), 20 weeks (=20.0 weeks, SD=6 days, range=18.3–20.6 weeks), 26 weeks (=26.1 weeks, SD=6 days, range=24.6–28.5 weeks), 32 weeks (=31.7 weeks, SD=3 days, range=30.4–32.4), and 37 weeks (=37.0 weeks, SD=4 days, range=36.2–38.1).
Each woman was interviewed prior to ultrasound imaging to record whether there were any changes in work or family stress (ie, stressors that could possibly affect the movement of the fetus) that she may have perceived over the preceding 6 weeks. The third author obtained the images in mid-afternoon with the woman in a semi-recumbent position, with diminished lighting, consistent with clinical obstetrical imaging. People who were significant to each woman were encouraged to attend the imaging. One day after birth (=39.9 weeks, SD=7 days, range=38.4 –41.4 weeks), the newborns were video-taped in 3 randomly assigned positions: right and left side lying and supine. The prone position was not used because hand movement was constrained in that position. The camera was positioned above the infant so that the whole body could be viewed. The side-lying position was maintained by a bendable positioning aid (Bendy Bumper
). An overhead heater maintained the unclothed child's temperature at 37° to 38°C. Super-VHS videotapes were copied with a digital time code. The mean duration of the videotaped images was recorded (Tab. 4). The percentages of fetal imaging film in which either the right or left hand, or both, could be visualized and scored were 83%, 83%, 91%, 86%, and 87% for the 5 imaging sessions, respectively. A mean of 74 minutes of imaging per subject (SD=1.8) was available for assessment. The total time that hands could be seen was determined and became the baseline for figuring the percentage of time (duration) that the hands were moving to and were at 1 of 7 locations. This percentage was calculated for each hand movement, for each fetus, at each age. The percentage of time available for scoring postnatally was 76% because the movement of the infant was not scored in Brazelton-designated states 1 (deep sleep) and 6 (crying).34 The frequency was the number of times that a specific hand movement occurred within the total time that the hands could be seen clearly and thus scored accurately.
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Videotapes were viewed randomly and scored by the first author. Ten percent of the videotaped images, randomly selected from all of the images, was scored independently by the first 2 authors. Percentage of agreement was determined for the scores for the right and left hands combined. A kappa statistic was generated to control for chance agreement. Overall mean percentage of agreement was 84% (range=65%–95%). The overall mean kappa was .72 (range=.57–.95). To achieve this level of reliability on a 2-dimensional viewing of a 3-dimensional movement, extensive training with non-subject images over several months prior to scoring of any subject's videotapes was necessary. Agreement was similar for all movements.
Data Analysis
Two major approaches were taken to analyze the duration and frequency data: use of the nonparametric Friedman 2-way analysis of variance by ranks and a follow-up of age differences using the Wilcoxon signed-ranks test. Nonparametric tests were selected so that no assumptions were made about the measurement scale or the distribution of the data. The Friedman 2-way analysis of variance by ranks was used with each fetal subject acting as its own control. We believe that this approach increases precision because measurements across the time points are correlated with one another. With this nonparametric approach, 2 types of comparisons were made: (1) the row-mean-score statistic (chi square with number of repeated measurements minus 1 degree of freedom) identified overall differences in scores of motor responses at different gestational ages for each movement, and (2) the correlation statistic (chi square with 1 degree of freedom) accounted for the ordering of the repeated measurements, which was used to identify linear trends in the data. When overall differences but no trends were observed, pair-wise comparisons were examined (P=.01) to detect differences. When trends were observed, pair-wise comparisons were used (P=.05) to indicate any possible support for the trend. To determine the association between fetal and neonatal measurements, Spearman rank correlations and a regression were computed. Statistical results are presented in terms of (1) overall differences, (2) trends, and (3) differences over the 6 time periods for data on durations and data on frequencies. Figures 1
through 6 show results of durations only.
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| Results |
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TopAbstractIntroductionBackgroundMethodResultsDiscussionConclusionAppendixReferences |
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through 6. Medians and ranges have been used in cases of fetal data variability.12 These maximum scores were distributed randomly over the 21 subjects, with no outliers. For essentially all behaviors at all ages, the range in percentages of duration extended from 0% to the maximum percentage shown for one subject. Movement durations are depicted in Figures 1 through 6. At each gestational age and at neonatal day 1, the median percentage of duration of the 6 movements for the right and left hands combined is shown. To permit scoring of all movements, we scored 7 categories of movement, including the "hand to/at the trunk" movement. Few instances of the "hand to/at the trunk" movement were observed, so analysis was not conducted on this movement.
Prenatal and Postnatal Duration of Movements
There was a difference between prenatal and postnatal duration of movements over the 6 time periods. The percentages on which these results are based are shown in Figures 1 through 6.
Overall differences.
For all movements (P <.038) except the "hand to/at uterine wall/mattress" movement, overall differences existed (Figs. 1–5).
Trends.
Decreasing linear trends, from 14 weeks through the postnatal period, were noted in the following movements: "hand near mouth" (P <.005) (Fig. 2), "hand to/at knee/foot" (P <.006) (Fig. 4), and "hand away from body (in fluid)" (P <.012) (Fig. 5). Through the postnatal period, an increasing linear trend was noted for the "hand to/at uterine wall/mattress" movement (P <.043) (Fig. 6).
Pair-wise comparisons.
There was an increase in the "hand to/at mouth" movement postnatally (Fig. 1) when compared with each gestational week. Postnatal "hand to/at face/head" movement scores were not different from prenatal "hand to/at face/head" movement scores (Fig. 3). In contrast, the "hand to/at knee/foot" movement showed a decrease postnatally when compared with all gestational ages (Fig. 4).
Prenatal Duration of Movement Alone
Overall differences.
There were no overall differences in prenatal duration of movement for the "hand to/at knee/foot" and "hand away from body (in fluid)" movements (Figs. 4 and 5).
Trends.
A linear decrease (P <.001) existed over the gestational period in the "hand to/at mouth" movement (decrease in median duration of movement from 3 to 0, expressed as percentage of time observed) (Fig. 1) and the "hand near mouth" movement (decrease in median duration of movement from 21 to 3, expressed as percentage of time observed) (Fig. 2). No linear trends existed in the following movements: "hand away from body (in fluid)" (Fig. 5), "hand to/at uterine wall/mattress" (Fig. 6), and "hand at/to knee/foot" (Fig. 4).
Pair-wise comparisons.
Comparison of behaviors indicated duration of movement in the "hand to/at face/head" movement (Fig. 3) decreased (P <.002) between 14 and 32 weeks and increased (P <.008) between 32 and 37 weeks. The "hand to/at mouth" and "hand near mouth" movement comparisons were similar, with the 37-week data less than the 14-week data (P <.003) and the 20-week data (P <.035) (Figs. 1, 2). For the "hand to/at mouth" movement, the 37-, 32-, and 26-week data were also different from the 14-week data (P <.025) (Fig. 1).
Although there were small median percentages for the "hand to/at knee/foot" movement over the gestational period, there was an extremely wide range of this movement at 32 weeks and even at 37 weeks of gestation (Fig. 4). Observed decreases in duration of movement in the "hand away from body (in fluid)" movement at 26 weeks were not significant due, in part, to 3 subjects whose durations were maximum for this movement (Fig. 5). For these same subjects, durations at 26 weeks for the "hand to/at uterine wall/mattress" movement were minimum.
Prediction
In an attempt to predict postnatal measurements, Spearman rank correlations resulted in the "hand to/at face/head" movement showing the only "promising" association. A regression analysis indicated that scores at 32 weeks of gestation were the best predictors of postnatal scores (P=.026).
Prenatal and Postnatal Frequency of Movement
With the postnatal data included, there were overall differences in the frequency data in all 6 movements (Tab. 5). Few trends, however, were noted. The only frequency trend confirmed the decreasing duration trend for the "hand to/at knee/foot" movement from 14 weeks of gestation to postnatal day 1. Follow-up pair-wise comparisons among the time periods showed the influence of the postnatal data on the analysis. The prenatal data, therefore, were evaluated without the postnatal data.
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| Discussion |
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TopAbstractIntroductionBackgroundMethodResultsDiscussionConclusionAppendixReferences |
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Hand Directedness
At the level of analysis of this study, fetal hand behaviors were described in terms of movement directed to and at a body part. The apparent goal orientation of fetal movement from 14 weeks of gestation led us to assume a functional importance for the movements. Whether the modifier of "function" was incorrectly used in this study or applied to the wrong behaviors is unclear. A developing sensorimotor system, however, apparently was being observed. Movement of the hand occurs around the mouth with frequent subsequent sucking, and movement of the hand to specific body parts occurs with subsequent molding of the hand around the body part. Movement of the hand to the uterine wall can be observed, with subsequent flattening and sliding of the palm against the uterine wall. Fingering, grasping, and manipulation of the umbilical cord occurs. Fetal grasping of the umbilical cord can cause variable heart rate decelerations35 and thus may be a behavior critical to assess in future studies. The functional appearance of much of fetal movement suggests the potential early relationship of sensorimotor status and environmental conditions that constrain or enhance movement (ie, affordances).36–38
These directed paths of movement are reminiscent of "contact paths" described in the ontogeny of facial grooming in mice,39 a functional activity achieved by modifying environmental permissive conditions. Future intervention by physical therapists as well as obstetricians with fetuses and neonates may be better contemplated after identifying functional correlates of complex behavioral repertoires and recording environmental characteristics that permit their occurrence.
Variability
The wide ranges of scores of the movement of these low-risk fetuses was anticipated. Some authors12,13 have noted this variability in young developing fetuses. Variability is a characteristic of "low-skill" movement,40 a category into which low-risk fetal movement certainly falls. This variability may well be modified by a myriad of as yet unexplored exogenous as well as endogenous factors. We interpreted the variability that we observed in our study as a dynamic characteristic of human movement. Decreased variability, presenting as stereo-typical behavior, may be observed in high-risk fetuses or those fetuses with a problem with sensorimotor adaptation.43 Indeed, the movement of fetuses with neural tube defects has been observed as lacking in variability. In addition to our observations of variability, our results suggest that there was an emerging underlying structure. The combination of variations in variability and changes in movement during gestation might provide data to assist in prenatal diagnosis.
Postnatal Period Versus Prenatal Period
Differences in the movement scores occurred between the prenatal and postnatal periods. We assumed that these differences are based on physiological and environmental factors known to occur over the transition from the fetal period to the neonatal period. Neural maturation over the brief span between 37 weeks of gestation and 1 day after birth could not be sufficient to be responsible for these changes. The data show an increase in the "hand to/at mouth" and "hand near mouth" movements postnatally, a decrease in the "hand to/at knee/foot" and "hand away from body (in air)" movements, and an increase in the "hand to/at uterine wall/mattress" movement. These results are compatible with neonates' participation in control of the regulation of their behavioral state36 and with the increased effect of gravity after birth. It is possible that the differences noted between the fetuses and the neonates could be used diagnostically (ie, if no differences were noted, delay or other developmental problems might be suggested). Because of the multitude of changes occurring over the birth transition, this interpretation is highly speculative at present.
Measurement of changes in movement across this transition have been difficult in the past because of a lack of an assessment tool that could compare the same behaviors in 2 totally different environments. The differences noted in our study suggest that we are measuring the effects of differing environmental factors that encourage or restrain movements. At present, extensive analysis of specific movements across this transition may provide spurious results. Research emphasis may best be placed on further analysis of the uterine environment, an ecological approach not unfamiliar to dynamical systems research on movement.41
Trends
Our hypothesis that the "hand to/at mouth" movement would be performed more frequently as development progressed was not supported. Instead, there was a linear decrease in the occurrence of this movement throughout gestation, with the hypothesized increase being observed only neonatally. The "hand to/at mouth" movement appeared in the newborn where it could be interpreted as a more functional activity assisting in neonatal modification of behavioral state and oral feeding. This type of developmental trend may be depicting the adaptedness of the organism to changing environmental and intrinsic challenges. The linear decrease in the occurrence of the "hand to/at mouth" and "hand near mouth" movements during gestation in our study is difficult to compare with the findings of other studies because of methodological differences. Roodenburg et al13 and de Vries et al14 identified a decrease in general movements over the gestational period, a result that was consistent in our data with only the "hand to/at mouth" and "hand near mouth" movements.
Other trends (U-shaped, inverted U-shaped) are apparent in our data. The decrease in the occurrence of the "hand to/at face/head" movement at 32 weeks and the "hand near mouth" movement at 37 weeks recalls regression curves described in the human infant,25 in which a movement occurs, disappears, or is of short duration and later reappears, often in a more advanced pattern. At 32 weeks, the "hand away from body (in fluid)" movement was observed more often than the other hand movements. At 37 weeks, the "hand to/at face/head" movement was observed more often than the other hand movements. Only neonatally were the "hand to/at mouth" and "hand near mouth" movements observed. Although the fetus is able to move the hands to or at the mouth and to other specific locations prenatally, only in the postnatal period may this movement pattern be considered "intentional," as Butterworth and Hopkins22 have suggested. The tendency for the "hand to/at knee/foot" and "hand away from body (in fluid)" movements to peak at 32 weeks may reflect some tactile proclivity in the mid-gestational fetus, gravitational constraint in the newborn, and neural maturation. The potential relationship of hand movements and neural status was not a direct focus of this study. Changes in these fetal behaviors, however, suggest that a developmental process could have been observed and that underlying that process would be neural, as well as musculoskeletal and physiological, maturation.
Frequency data indicated that declines occurred over the course of gestation, with increases in frequency occurring neonatally, suggesting possible space limitations as gestation progressed. This finding was not true for the "hand to/at knee/foot" movement data, which showed a decreasing trend through day 1, indicating the difficulty postnatally of antigravity movements of large body parts, as suggested by Thelen and Ulrich's work.25
Another difference was the decrease in frequency of the "hand to/at face/head" movement at 37 weeks, coinciding with an increase in duration of the "hand to/at face/head" movement during this period. This decrease in frequency at 37 weeks might be attributed to increasing energy conservation in preparation for birth, as well as to decreasing uterine space.
Limitations
Scoring based on a 3-dimensional view of a 3-dimensional movement threatens the credibility of the data. The achievement of good reliability was based on extensive training. Although the observers' scores were reliable, it is possible that they were not scoring the true behaviors or that the behaviors were being modified by the procedures (eg, the imaging). Three-dimensional viewing is currently being used to assess patients with breast cancer, but it has not been commonly available to assess the movement of fetuses. The future availability of this technology may assist observers in more valid scoring.
The number of subjects in this study was relatively small. Additions to this database might permit further analysis, such as analysis of differences between male and female fetuses. Achieving significance in some movements using nonparametric statistics, specifying the actual amount of data used for analysis, and using a variety of subjects over the course of pregnancy with follow-up do not lessen the need for a larger subject pool.
We did not assess fetal behavioral state directly, and we scored neonatal movements only in behavioral states 2 through 5.34 Although the initial linkage among the behavioral state variables of movement, heart rate, and eye movements may appear earlier (ie, at 20 weeks42,43), Swartjes et al44 determined that "true behavioral states" were not found until 32 weeks of gestation. An attempt was made to consider variability in behavioral state factors in the following ways: by scoring the movements of over 20 subjects, by performing ultrasound imaging at least 2 hours after a meal so that glucose levels would not affect the movement, and by assessing fetuses at approximately the same time of day. Diurnal variation in fetal movement has been established45 and could affect the duration and frequency of movement.
Concerns about the safety of ultrasound imaging have limited fetal research in this country. Human subject review committees and granting agencies have questioned the risk-benefit ratio of the use of this technology. In our study, identification of additional subjects, rather than increasing observation time, was used to obtain data for analysis. Recent increases in the amount of imaging time allowed by federal granting agents42 are welcomed and supported by long-term studies on the safety of ultrasound imaging.31 Most of the studies conducted in the Netherlands have used 1-hour imaging segments for analysis.
The results of studies of nutritional and other environmental factors vary. Based on research describing social influences on pregnancy,46,47 there should be consideration of the potential effect on fetal movement of the environment beyond the uterus. Differences in lifestyle, nutrition, family, work, and stress levels may help to explain the large variance that all investigators have observed in movement duration and frequency. The demographics of this sample describe a wide variety of occupational and educational experience. These influences need to be disentangled in future studies, as their components might affect motor development.
Future Directions
Investigation of fetal sensorimotor development may detect behavioral patterns characteristic of impairment4,48–50 and may increase our understanding of dis-orders such as cerebral palsy. Current data suggest that 60% of neurodevelopmental disabilities are caused during the prenatal period.51 Within this category, cerebral palsy has been reported to be the most "life-limiting" of childhood disabilities. Kuban and Leviton have stated that "efforts to prevent cerebral palsy will require a focus on factors and events during pregnancy, including those that predispose the mother and fetus to preterm delivery."52(p193) Identification of changes in movement patterns over gestation may assist in explicating the role of some of these factors and events.
To address such critical questions, appropriate assessments will be necessitated. As the category of "general movements" is being further specified, so too may the movement patterns that we studied. Theoretical applications, such as those expressed by Sporns and Edelman,53 will be important guides in this process. Further behavioral analysis of the human fetus may provide needed information about approaches and equipment that to date have not been fully tested.
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TopAbstractIntroductionBackgroundMethodResultsDiscussionConclusionAppendixReferences |
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| Appendix |
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| Acknowledgments |
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| Footnotes |
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This study was approved by the Committee on the Protection of the Rights of Human Subjects, School of Medicine, University of North Carolina at Chapel Hill.
* Phillips Medical Equipment, 710 Bridgeport Ave, Shelton, CT 06484. 
Panasonic, 1 Panasonic Way, Secaucus, NJ 07094.
Observational Coding System (OCS), Triangle Research Collaborative Inc, PO Box 12167, Research Triangle Park, NC 27709.
Children's Medical Ventures Inc, 541 Main St S, South Weymouth, MA 02190.
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