| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Research Reports |
AM Megens, PT, MSc, is Physical Therapist, Ottawa Children's Treatment Centre, Ottawa, Ontario, Canada
SR Harris, PT, PhD, FAPTA, is Professor, School of Rehabilitation Sciences, Faculty of Medicine, University of British Columbia, T325-2211 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2B5
CL Backman, PhD, OT(C), is Associate Professor, School of Rehabilitation Sciences, Faculty of Medicine, University of British Columbia
VE Hayes, PhD, RN, is Professor, School of Nursing, University of Victoria, Victoria, British Columbia, Canada
Address all correspondence to Dr Harris at: shar{at}interchange.ubc.ca
Submitted March 25, 2006;
Accepted September 11, 2006
 | Abstract |
|---|
Subjects and Methods: Following HINT administration by trained health care professionals, scores were compared for 54 high-risk infants and 412 low-risk infants with a t test.
Results: Mean HINT scores for infants at low risk were lower than mean scores for infants at high risk, as would be expected in that higher scores indicate higher risk. Significant differences were found at 4, 5, 7, and 8 months. At 6 months, there were no significant differences. There were not enough high-risk infants in other subgroups for reliable comparison.
Discussion and Conclusion: The HINT appears to discriminate effectively between infants who are at low risk and infants who are at high risk for neuromotor delays, supporting the use of the HINT as a screening tool for infants in the first year of life.
| Introduction |
|---|
 TopAbstract Introduction MethodResultsDiscussionConclusionReferences |
|---|
Neuromotor screening tests are designed to differentiate infants and children who are having difficulties in their motor development from those who are developing typically. Infants with suspected neuromotor delays then can be referred for more comprehensive assessments and specialized services, if required. Typically, follow-up programs are located in tertiary hospitals, in which only selected infants who are at high risk for developmental concerns are assessed longitudinally. A number of factors can contribute to infants being at risk for developmental delays, including preterm birth (<37 weeks of gestation),7,8 low birth weight (<2,500 g for full-term infants),9 and prenatal exposure to drugs10 or alcohol.11,12
The Harris Infant Neuromotor Test (HINT) is a developmental screening test that was designed for administration by physical therapists, occupational therapists, family physicians, pediatricians, and community health nurses who are involved in early infant screening. It can be administered and scored in less than 30 minutes and requires very little special equipment, making the test portable. The HINT is aimed at identifying early motor delays in infants as well as early signs of cognitive or behavioral concerns. It was created for use in infants from 2.5 to 12.5 months of age.
The first edition of the HINT was assessed for content validity by an international panel of experts, whose comments resulted in the second edition of the HINT.13 The second edition of the HINT has demonstrated excellent interrater reliability (intraclass correlation coefficient [ICC]=.99), test-retest reliability (ICC=.98), and intrarater reliability (ICC=.98–.99).14 The HINT also has shown good concurrent validity with the Bayley Scales of Infant Development-II (Bayley-II). With Pearson r correlations, the concurrent relationship between the HINT and the Bayley-II Mental Scale was determined to be .73, and that between the HINT and the Bayley-II Motor Scale was determined to be .89.14
Compared with other infant motor assessment tools, the HINT is unique in that it includes a section comprising 5 questions to assess the caregiver's level of concern about the infant's movement and play. Early HINT research showed that parents were quite accurate in estimating whether their infant's motor development was delayed or within normal limits in comparison with standard scores on the Bayley-II Motor Scale; the sensitivity was 80%, and the specificity was 91%.15 The HINT is the first infant neuromotor screening test to have been standardized for an ethnically representative normative sample of Canadian infants16 and was designed to be administered by a wide variety of different health or early childhood professionals, such as community health nurses, general practitioners, and early childhood special educators, in addition to physical therapists and occupational therapists.17
The purpose of this study was to determine whether the HINT, an infant neuromotor screening test, could distinguish between infants who are at low risk for developmental concerns and infants who are at high risk for developmental concerns. We used the known-groups method9 to examine the construct validity of the HINT to address this research aim.
| Method |
|---|
|
TopAbstractIntroductionMethodResultsDiscussionConclusionReferences |
|---|
Inclusion criteria for the low-risk group were full-term birth (37–42 weeks of gestation), birth weight of greater than 2,500 g, and no history of prenatal, perinatal, or postnatal medical complications or maternal complications. Exclusion criteria for normative data collection included premature birth (<37 weeks), low birth weight (<2,500 g), a history of maternal alcohol or drug use during pregnancy, and any other high-risk medical condition for the mother or infant, such as a chromosomal abnormality or a congenital heart defect. There were 412 infants in this group, with 208 boys and 204 girls ranging in age from 2 months 16 days to 12 months 15 days.
Infants who were considered to be at high risk for developmental delays were recruited as part of a larger study evaluating the concurrent validity and predictive validity of the HINT.14 These infants were recruited from 2 high-risk follow-up programs in Vancouver, British Columbia: the Infants and Children at Risk Program at Sunny Hill Health Centre for Children and the Neonatal Follow-up Program at British Columbia Children's Hospital. Infants were considered to be at high risk for developmental delays because of premature birth (23–32 weeks of gestation) (n=34), low birth weight (<2,500 g) (n=28), or prenatal exposure to alcohol, drugs, or both (n=33). Thirteen of the high-risk infants also had major medical concerns, including intraventricular hemorrhage, periventricular leukomalacia, bronchopulmonary dysplasia, seizures, hydrocephalus, microcephaly, or patent ductus arteriosus; 6 others had severe meconium aspiration. Age was corrected for infants born at less than 38 weeks of gestation. Fifty-four high-risk infants (19 girls and 35 boys ranging in age from 3 months 2 days to 12 months 9 days) participated. Table 1 shows demographic characteristics for both groups.
|
The HINT consists of 3 parts. The first part is for recording background information on the child and his or her caregiver. The second part is a series of questions directed at the parent or caregiver regarding the infant's development. The final part of the assessment consists of 21 items regarding motor behaviors that are either observed or assessed through handling of the infant (eg, muscle tone). Total scores are derived from a sum of all scores for each of the 21 motor behavior items. Higher scores indicate higher risk.
Known-Groups Method for Assessing Construct Validity
The known-groups method was used to assess the construct validity of the HINT; construct validity is a type of measurement validity that reflects the ability of a test to measure a construct or abstract concept.18 The known-groups method can be used to examine differences between groups of people who are known to have a trait, such as infants at risk for developmental delays, and groups of people who do not have this trait. A criterion must be selected to identify the presence or absence of a certain characteristic that will differentiate between the groups.18 In our study, the criterion used was the degree of risk for atypical infant motor performance. In other words, we selected one group of infants who were at low risk for motor delays (full-term, appropriately grown infants with no known medical concerns) and a second group of infants who were shown through prior research7–12 to be at risk for developmental delays (infants born preterm, infants with low birth weight, or infants exposed to drugs or alcohol in utero). If differences between the groups are statistically significant, then the validity of the test for distinguishing between the groups is supported.
Data Analysis
Intraclass correlation coefficients were used to determine interrater reliability between the HINT course instructor and trainees in the administration of the HINT. Each of the 19 assessors was found to be reliable when test scores were compared with those obtained by the course instructor, with ICCs ranging from .93 to .99.
For HINT scoring, infant ages are grouped such that infants from 2 months 16 days to 3 months 15 days are considered to be in the same monthly age group, that is, 3 months. Means and standard deviations were calculated for each of the 10 monthly age groups on the basis of the age of the infant at the time of assessment. For infants born at less than 38 weeks of gestation, corrected ages were used. To determine whether there were significant differences in scores on the basis of sex and therefore whether data could be pooled, a t test comparing scores for boys and scores for girls was used for the total group. To assess known-groups validity, a t test assuming unequal variances was used to determine whether there were significant differences in HINT total scores between high-risk infants and low-risk infants as a whole group and at each monthly age level. The alpha level was set at P<.05 for these analyses.
| Results |
|---|
|
TopAbstractIntroductionMethodResultsDiscussionConclusionReferences |
|---|
Known-Groups Validity
The t test calculations demonstrated a significant difference in HINT total scores between infants at high risk and infants at low risk (t=–4.25, P<.001). In the high-risk infant group, there were only 2 infants in each of the age groups of 3, 11, and 12 months, 4 in the 9-month age group, and none in the 10-month age group, so these age groups were omitted from further statistical analysis because of insufficient numbers. For the remaining age groups of 4, 5, 6, 7, and 8 months, mean HINT scores for infants at low risk for developmental delays were lower than mean HINT scores for infants at high risk for developmental delays, as anticipated (Tab. 2). Statistically significant differences in HINT scores were found at ages 4, 5, 7, and 8 months, with t test values of –3.51 (P=.001), –2.20 (P=.033), –3.45 (P=.001), and –3.65 (P=.001), respectively. Scores did not differ at 6 months (t= –1.72, P=.091).
|
| Discussion |
|---|
|
TopAbstractIntroductionMethodResultsDiscussionConclusionReferences |
|---|
With the 8-month age group as an example (Tab. 2), the mean total HINT score was almost twice as large for the high-risk group as for the low-risk group (23.87 versus 12.29). Nonetheless, the large standard deviation for the high-risk group (17.87) indicates that some of the 15 high-risk infants performed within normal limits on the HINT. Because these infants were at high risk but had not necessarily been diagnosed as having neuromotor impairment, this finding is not surprising. Because the HINT is only a screening test, clinicians also need to continue to rely on their clinical experience and judgment in determining whether an infant has neuromotor impairment. If the decision remains uncertain, further examination with a more comprehensive assessment, such as the Bayley-III19 or the Peabody Developmental Motor Scales,20 is warranted.
Whereas the known-groups method supports the construct validity of a test, predictive validity is a type of criterion-related validity that also is essential in screening tests.18 Both types of analysis are important in supporting the validity of a test. Previous research on the HINT involving a sample of 54 high-risk infants showed that the predictive correlation between the HINT (administered at between 3 and 12 months) and the Bayley-II Motor Scale (administered at 17–22 months) was r=–.49 (P<.01), a modest relationship, suggesting that the HINT accounted for about 24% of the later Bayley-II Motor Scale outcome.14 Nonetheless, this relationship compares favorably with the predictive correlation between the Alberta Infant Motor Scale (AIMS), another infant motor screening test, at 6 months and the Bayley-II Motor Scale at 12 months (r=.56)21; this time interval is much shorter than that used in the comparison between the HINT and the Bayley-II Motor Scale, that is, 6 months versus approximately 11 months. The results of both the current known-groups analysis and the previous predictive validity study14 support the overall validity of the HINT as a screening test.
The known-groups method for establishing the construct validity of a test was used previously in the investigation of other infant screening tests. Validity testing of the Test of Infant Motor Performance, a test of motor and postural control for infants less than 4 months of age, provides an example of known-groups analysis for groups of infants at low risk and at high risk for developmental difficulties but not yet diagnosed. In examining the ability of the Test of Infant Motor Performance to discriminate among 5 groups of infants with variable risks for a poor motor outcome, Campbell and Hedeker22 reported that the test was successful in discriminating between low- or medium-risk infants (groups 1 and 2) and high-risk infants (groups 3, 4, and 5). In addition, the highest-risk group, infants with brain insults (group 5), performed significantly more poorly than infants in the other 4 groups.
Fetters and Tronick23 examined the ability of the AIMS to discriminate between 28 infants with prenatal cocaine exposure and an unexposed control group of 22 infants (matched for race, family income, and maternal education level). Although there were no between-group differences on the AIMS at 1 month of age, significant differences were reported at 4 and 7 months of age.
Similarly, our validity testing compared low-risk and high-risk infants. The infants at high risk had not been diagnosed with a neuromotor delay but were at risk for such a delay. The fact that the HINT was able to discriminate between 4 of the 5 low-risk and high-risk groups, even with very small subject numbers in the high-risk group, lends support to the ongoing validation of the HINT. We are currently conducting longitudinal assessments of 100 low-risk and 100 high-risk infants with the HINT at 4–6 months and 10–12 months. The results of that research will enable us to further examine the ability of the HINT to discriminate between larger groups of infants at these time points.
Limitations
Even though the results of our study demonstrated the ability of the HINT to distinguish between infants at low risk for developmental delays and infants at high risk, there were a number of limitations that may have affected our results. The data collection for the high-risk groups and the low-risk groups occurred at different points in time, and assessors for each group were not unaware of an infant's respective group classification. In addition, the 2 groups were unequal in size, with far fewer numbers in the high-risk group.
| Conclusion |
|---|
|
TopAbstractIntroductionMethodResultsDiscussionConclusionReferences |
|---|
| Footnotes |
|---|
Ethical approval for this study was obtained from the University of British Columbia Clinical Research Ethics Board.
The results of this study, in part, were presented as a poster at a Canadian Physiotherapy Association Congress; June 2002, Halifax, Nova Scotia, Canada.
The authors acknowledge funding support from The Hospital for Sick Children Foundation and the Social Sciences & Humanities Research Council (The CHILD Project).
| References |
|---|
|
TopAbstractIntroductionMethodResultsDiscussionConclusionReferences |
|---|
This article has been cited by other articles:
|
|
 |
|
  A. Scher, L. Tse, V. E. Hayes, and M. Tardif Sleep Difficulties in Infants at Risk for Developmental Delays: A Longitudinal Study J. Pediatr. Psychol., May 1, 2008; 33(4): 396 - 405. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
