|
|
||||||||
Original Research |
Nutrition Department, College of Human Ecology, University of Tennessee, Knoxville, Tennessee
Address reprint requests to: Betty Ruth Carruth, PhD, RD, Nutrition Department, University of Tennessee, Knoxville, TN 37996-1900. E-mail: bcarruth{at}utk.edu
| ABSTRACT |
|---|
|
|
|---|
Design: An incomplete block design was used with 57 to 60 (sample=98) mothers interviewed when their children were 2, 3, 4, 6, 8, 10, 12, 16 and 24 months (within ± 5 days of birth date). Each mother had 5 to 6 interviews.
Setting: Selected developmental feeding behaviors were monitored using in-home interviews conducted by trained interviewers (n=2). At each interview, mothers reported the childs age when behaviors first occurred, and anthropometric measurements were performed.
Subjects: Subjects were healthy white children who lived mostly in homes with educated two-parent families of upper socioeconomic status.
Results: Mean behavioral ages were within normal ranges reported in the literature, whereas individuals exhibited a wide diversity in reported ages. Examples of gross motor skills (age in months, ± SD) included sitting without help (5.50 ± 2.08) and crawling (8.00 ± 1.55). Mean ages for self-feeding fine motor skills showed children reaching for a spoon when hungry (5.47 ± 1.44), using fingers to rake food toward self (8.87 ± 2.58) and using fingers to self-feed soft foods (13.52 ± 2.83). Oral behaviors included children opening their mouth when food approached (4.46 ± 1.37), eating food with tiny lumps (8.70 ± 2.03) and chewing and swallowing firmer foods without choking (12.17 ± 2.28).
Conclusions: Mean ages for feeding behaviors occurred within expected age ranges associated with normal development. However, mothers reported that individual children exhibited a wide age range for achieving these behaviors. Our results should be considered in counseling mothers about infant feeding practices.
Key words: infant feeding behaviors, motor development, self-feeding
| INTRODUCTION |
|---|
|
|
|---|
The study objective was to track gross motor, fine motor and oral motor developmental patterns of 98 white, healthy children aged 2 to 24 months. The use of drinking and eating utensils was assessed for the same time period. This report represents the initial phase (2 to 24 months) of an ongoing comprehensive longitudinal study of healthy children (2 to 96 months). Data collected include growth indices, food intake, family environment, social development and socioeconomic factors that may influence food practices of children. By monitoring gross, fine and oral motor development, a data base was established that indicated the study children over time exhibited a range of behavioral patterns associated with normal feeding practices.
| METHODS |
|---|
|
|
|---|
7, birth weights of
5.5 pounds and absence of neonatal and birth anomalies). The strategy of recruiting a sample from middle/upper socioeconomic status and healthy infants addressed factors known to influence development and food intake such as healthy status versus infants with birth and/or neonatal anomalies, differences in growth patterns associated with ethnicity, the negative influence of lower socioeconomic status on food availability and access to health care and the effect of limited parental education. Study participants were recruited via birth announcements, posters displayed in health care facilities, personal referrals and through churches. A telephone contact was made initially to explain the study. For those expressing interest, occupational and educational information about the primary wage earner or both parents was obtained. Based on information given at that time, socioeconomic status was calculated by the Hollingshead Four Factor Index [17], and mothers were immediately informed about study eligibility. Enrollees in the study received letters providing further information about the study, giving informed consent, their responsibilities and benefits of participating in the study. The research protocol was approved by the institutional review board for use of human subjects. Mothers received $20 to $30 per interview depending on interview length.
Interview Sampling Design
To reduce the number of interviews per participant but also to have the statistical power to extrapolate findings to the group of 98 participants, an incomplete block design was developed for the study. This design allowed a sampling base of 57 to 60 subjects out of the 98 participants for each interview when the children were 2, 3, 4, 6, 8, 10, 12, 16, 20 and 24 months of age. The investigators were especially interested in motor development occurring in the first few months of life; thus, more interviews were conducted in the 2-to-12-month time period. In addition to the lower cost of collecting data, the study design provided sample sizes adequate for multivariate analyses. All mothers had five to six interviews in the 2 to 24 month period, with each mothers interview sequence computer randomized using the incomplete block design. Interviews for each mother were scheduled ± 5 days of their childs birth date.
Anthropometric and Dietary Data Collection
Two trained interviewers conducted in-home interviews for the same families throughout the 2-to-24-month period, using research protocols previously described [16]. At the initial interview, mothers reported demographic information, infant birth weight and associated neonatal health. Birth data reported by mothers were subsequently verified with medical records at health care facilities where the children were born. The two trained interviewers, using a standard protocol, measured children at each interview. Anthropometric measurements included using a fixed head and perpendicular sliding foot board for length (nearest 0.125 in), a plastic non-stretchable tape for head circumference (nearest mm) and calibrated scales (Detecto Doctors Infant Scale, Detecto Scale Company, Webb City, MO) for weight (nearest 0.25 oz). Measurements were made in triplicate and averaged for a single value. Inter-observer bias was reduced by having the same interviewer measure the same children during the 2 to 24 months. Periodically, the research staff assessed measurement stability over time (by interviewer/child pair) and checked calibrations of the equipment sets used by each of the trained interviewers.
Mothers reported the infants food intake, including breast milk and the childs other food intake for the previous 24 hours. Interviewers used food models, baby food containers and similar utensils to increase the accuracy of mothers recalls. The dietary results have been published and will not be included in this report [16].
Assessing Motor Developmental Markers
Developmental behaviors used in this study were generated using literature sources that provided descriptors of the behavior and the predictive age range within which the behavior was likely to occur in healthy children [1, 7, 8, 1722]. For the first 6 to 8 months, motor development behaviors were divided into developmental markers related to head and trunk stability, finger and hand movements, and tongue and mouth movements that a child could possibly exhibit. As the children matured (6 to 24 months), the list of motor development skills reflected increased complexity associated with maturation, and they also included several behaviors that a few children might achieve at an early age. For example, in the first six-month interviews, mothers were asked the age (months) when their baby sucked several fingers (average 2 months) compared to picking up and holding a spoon (average 6 to 8 months). Descriptors for these behaviors are listed in Tables 13. At each interview, pictures of infants performing these behaviors were available for about two-thirds of the descriptive statements used in this study, particularly for easily observable gross and fine motor development markers (e.g., sitting with help, grasping toy with fingers). For the more discrete tongue/mouth movements, pictures were not available; however, interviewers were trained to explain to mothers what specific oral movements were involved. The same interviewer for the same mother/child pair used probing and explanations to improve data collection.
|
|
To help mothers record data and track developmental behaviors during the 2 to 12 months, special prototype calendars were provided to the participants. Beginning at the eighth-month interviews, mothers also reported their childs ability to drink from a cup (with and without a lid), sip from a straw (large and small) and whether the child or the mother held the drinking utensil. Similar data about spoons (type and use) were reported by mothers.
Health Assessments
At each interview mothers were asked about their childrens visits to a physician, frequency and types of illnesses, hospitalizations and medications given to the child since the mother was last interviewed. This information was used to monitor these occurrences in relation to reported food intake and developmental patterns over the 2-to-24-month period.
Analyses
Using SAS [23], descriptive statistics were generated for anthropometry, the reported childrens ages at which motor developmental behaviors first occurred and infant birth weight. To determine if developmental patterns were related to birth weight and gender, male and female infants were grouped by their birth weight to form low, middle and high weight groups. General Linear Mixed Models (GLMM) were used for these analyses.
| RESULTS AND DISCUSSION |
|---|
|
|
|---|
Mean ages for gross motor behaviors of walking without help, climbing furniture and running without falling again are similar to results reported in the literature [1, 22, 24]. As reported by Frankenburg et al. [24], 50% of infants in the Denver II tests could stand alone well at 11.5 months and 90% at 13.9 months. In a study of 25 children (2 to 24 months), Shirley found that children climbed stairs at 13 months and stood alone at 14 months [21]. Thus, the study children had mean ages of achievement for selected gross motor development behaviors that are within published ages.
Fine Motor Development
Fine motor skills are more difficult to master than gross motor skills because they require precise coordination between complex muscle groups. In the 2-to-5-month period, the infants manipulation and exploration of an object changes. At earlier ages, the co-occurrence of infants mouthing and looking at a novel object may be performed. As shown in Table 2, the mean age that study infants brought a toy to the mouth was 3.29 ± 0.99 months. By four months of age, Rochat [2] reported that fingering behaviors increased with infants holding an object in one hand and using the other hand to explore the object with their finger tips. Rochat and Goubet [27] found that the ability to self-sit (compared to assisted sitting) allowed children to use either or both hands in object manipulation. Around six months, most infants can grab at and hold on to an object without visually following their hand to the object. As shown by Robin et al. [28], infants could grab illuminated objects in an otherwise dark environment that eliminated visualization of the hand moving toward the object. In our study, children (2 to 24 months) reached for a spoon when hungry at a mean age of 5.47 ± 1.44 months and could transfer toys or food from one hand to the other at 6.68 ± 1.63 months.
|
Indicators of Oral Motor Development
Childrens oral motor development begins with the mouth working as a total unit, but as the child matures, the movement of jaws, the tongue and lips function as separate entities. According to Morris [7],... "... by 6 months infants can move their tongue laterally when food is placed in the side of the mouth ... by 8 months, the tongue moves from the center of the mouth to the sides." By the second year, the tongue is able to make a smooth midline transfer of a food bolus. As shown in Table 3, there was a progression over time in which the coordination of jaw stability (opens mouth when food approaches), lateral tongue movements (moves food to back of mouth) and lip closure (keeps most food in mouth) increased in efficiency. A literature survey indicated that no recently published studies were available to compare our data with other groups of children, aged 2 to 24 months.
The ability to chew a variety of foods with varying firmness and texture is associated with normal tooth eruptions in the first two years of life [30]. The diagram in Fig. 1 indicates the normal distribution of teeth in the maxillary (upper) and mandibular (lower) jaws, and the mean ages indicate when these teeth erupted during the 2-to-24-month period. The teeth labeled E, F, P, and O are used in biting or breaking off food pieces and were present in the study children by a mean age of 7 to 10 months. The cuspids and molars associated with grinding and lateral mandibular movements erupted in the 12-to-18-month period; this corresponded with data shown in Table 3 that described the chewing behaviors reported by mothers. In general, the mean ages for tooth eruptions of the study children were within expected age ranges.
|
|
Before 12 months about 15% of mothers reported children using straws. By 16 months a majority of the children used large straws (Fig. 3). In the earlier months, mothers held the straw, whereas by 16 months most children were permitted to hold their own straws. Anecdotal comments from mothers indicated that eating away from home was the major occasion during which children used straws.
|
|
| CONCLUSIONS |
|---|
|
|
|---|
Our findings also demonstrate the wide age range within which healthy children as a group and as individuals achieved the 33 behaviors identified in the study. Results also describe developmental interrelationships that support the process from the infants being fed to self-feeding. For example, at 5 to 7 months, children could sit in the care-takers lap without assistance, reach for a spoon when hungry and use the tongue to move soft food and liquid to the back of the mouth for swallowing. These movements require a degree of head and trunk stability which frees the arms and hands for maneuvering food toward the mouth, enhances swallowing and/or reduces the potential for choking that occurs if the infants were in a supine position. Similarly, the lower and upper front teeth (Fig. 1, teeth O, P, E, F) and related self-feeding behaviors first occurred within the 7-to-9-month period. Concurrently, the children were eating finger foods without gagging and biting off pieces of food (Table 2). These behaviors require hand/eye coordination and more precise control of arm and hand movements that also involve head and trunk stability. A developmental delay in gross, fine or oral motor development negatively impacts on learning to self-feed.
Results of this study suggest a sequential process for 33 behaviors that characterize the group, but not every child reportedly experienced a sequence. Some individual children never exhibited selected behaviors and/or they skipped certain behaviors, such as supporting weight on the forearms. These differences between individuals achieving or not achieving selected behaviors may be explained by the Thelen theory [32]. It is posited that developmental progress of infants is the consequence of the system (infant) and active exploration of how to solve the problem (raking and spearing food). Alternate explanations would be that some mothers limited their childs autonomy to explore because of accompanying messiness and spillage and/or some children were maturing at a slower rate and were unable to perform discrete behaviors comparable to their peers. Although calendars and other types of data collection records were used, mothers may not have known the exact age at which a behavior first occurred. This explanation of the diversity among children is offset by the fact that the same trained interviewer saw and measured the same child each time, and many of the behaviors could be observed.
The question arises about generalizing our findings to infants of different socioeconomic status and ethnicity. However, in comparing gross and fine motor development in our study with published data from a large representative sample (included different socioeconomic and ethnic groups) and from a smaller longitudinal study [21, 24], our study findings were similar for the mean ages at which selected behaviors first occurred (e.g., sitting without help, holding a toy or spoon). The strength of this longitudinal data (2 to 24 months) relies on multiple interviews, monitoring the infants health status throughout the study period and having trained interviewers to observe the same mother/infant pair for the 2-to-24-month period.
In conclusion, children in our study exhibited age-appropriate developmental behaviors related to feeding practices and self-feeding with individual children exhibiting a wide age range at which behaviors first occurred. Our results could be used in counseling parents who may not be aware of or appreciate these individual behavioral differences that occur among healthy children. In addition, parents may need encouragement about allowing their children to autonomously explore activities related to the feeding process and to developing age-appropriate feeding solutions.
| ACKNOWLEDGMENTS |
|---|
This research was funded by Gerber Products Company, Fremont, MI.
Received April 24, 2001. Accepted October 24, 2001.
| REFERENCES |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
C. Agostoni, G. V. Zuccotti, G. Radaelli, R. Besana, A. Podesta, A. Sterpa, A. Rottoli, E. Riva, and M. Giovannini Docosahexaenoic acid supplementation and time at achievement of gross motor milestones in healthy infants: a randomized, prospective, double-blind, placebo-controlled trial Am. J. Clinical Nutrition, January 1, 2009; 89(1): 64 - 70. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |