Learning Problems in Kindergarten Students with Extremely Preterm Birth

Abstract

Objective

To assess learning problems in extremely preterm children in kindergarten and identify risk factors.

Design

Cohort study.

Setting

Children’s hospital.

Participants

A cohort of extremely preterm children born January 2001 – December 2003 (n=148), defined as <28 weeks gestation and/or <1000 g birth weight, and term-born normal birth weight classmate controls (n=111).

Main Interventions

The children were enrolled during their first year in kindergarten and assessed on measures of learning progress.

Main Outcome Measures

Achievement testing, teacher ratings of learning progress, and individual educational assistance.

Results

The extremely preterm children had lower mean standard scores than controls on tests of spelling (8.52 points, 95% CI: 4.58, 12.46) and applied mathematics (11.02 points, 95% CI: 6.76, 15.28). They also had higher rates of substandard learning progress by teacher report in written language (OR = 4.23, 95% CI: 2.32, 7.73) and mathematics (OR = 7.08, 95% CI: 2.79, 17.95). Group differences on mathematics achievement and in teacher ratings of learning progress were significant even in children without neurosensory deficits or low global cognitive ability. Neonatal risk factors, early childhood neurodevelopmental impairment, and socioeconomic status predicted learning problems in extremely preterm children, yet many of the children with problems were not in a special education program.

Conclusion

Learning problems in extremely preterm children are evident in kindergarten and are associated with neonatal and early childhood risk factors. The findings support efforts to provide more extensive monitoring and interventions both prior to and during the first year in school.

Extremely preterm (EP) children born before 28 weeks gestation and/or with <1000 g birth weight are at high risk for neurodevelopmental disorders.¹ These disorders range from severe conditions, such as cerebral palsy (CP), sensory deficits, and global mental deficiency, to more subtle impairments in cognition, behavior, and academic achievement, with many EP children requiring special educational assistance during their school-age years.^2–12 Academic difficulties are of particular concern once EP children begin kindergarten, as failure to recognize these difficulties can delay special educational interventions.¹³

Unfortunately, we know little about the educational progress of EP children during this critical period of schooling. Several studies have documented academic difficulties at early school age on tests or teacher ratings of achievement.^{11,12,14–24} However, this previous research has not examined the nature and predictors of learning problems in kindergarten. Knowledge regarding early academic outcomes is vital in appraising the educational needs of these children and their prospects for future learning problems.^25–29 Information on neonatal and early childhood factors related to poor achievement in kindergarten would also be useful in identifying the children most in need of careful monitoring.

Our primary objectives were to assess early learning progress in EP children compared with term-born normal birth weight (NBW) controls and examine associations of educational outcomes in the EP group with neonatal factors, early childhood neurodevelopmental impairment, and socioeconomic status (SES). The primary hypothesis was that rates of academic problems and learning assistance would be higher for EP children than for NBW controls.^{3,12,21,23,24,29} Secondary hypotheses were that: (a) group differences would remain even when excluding children with more severe deficits^20,30; (b) many children in the EP group with academic problems would not be receiving special assistance in school;^10,31,32 and (c) higher rates of learning problems in the EP group would be associated with neonatal risk factors, early childhood neurodevelopmental impairment, and lower SES.^{3,18,19,25,33–43}

METHODS

PARTICIPANTS

Two hundred forty six children born with <28 weeks gestational age and/or <1000 g birth weight were admitted to the neonatal intensive care unit of Rainbow Babies & Children’s Hospital in Cleveland, Ohio during the period January 2001 – December 2003, excluding 8 infants with congenital infections or abnormalities. Of the 198 (80%) who survived, 148 (75%) were enrolled in the study. Reasons for non-participation included failure to locate families (21 cases), moves out of the region (16 cases), and refusals or no-shows (5 cases). Eight children could not be assessed due to custody issues or because they were non-English speaking. Comparison of participants with non-participants failed to reveal significant differences in ethnicity, sex, or neonatal risk factors. The children were followed longitudinally and contacted during their initial year in kindergarten. One hundred twenty nine EP children attended regular classrooms, 16 were in full-time special education programs, and 3 were home-schooled.

The EP group comprised 56 (38%) children had birth weight <750 g, 32 (22%) with gestation <25 weeks, and 37 (25%) with birth weight <10^th percentile for gestational age.⁴⁴ Neonatal complications included abnormal ultrasound defined as Grade III/IV intraventricular hemorrhage, periventricular leukomalacia, or ventricular dilatation at discharge (15, 10%); brochopulmonary dysplasia defined as supplemental oxygen at 36 weeks corrected age (77, 52%); infection and/or necrotizing enterocolitis (67, 45%); and severe retinopathopathy of prematurity defined as Stage 4 or 5 retinopathy or receipt of cryotherapy or laser therapy⁴⁵ (27, 18%). At 20 months corrected age, 60 EP children (41%) had neurodevelopmental impairment defined as cerebral palsy (CP) (13, 9%), blindness or deafness (6, 4%), or a score <70 on the Mental Development Index of the Bayley Scales of Infant Development, 2^nd Edition⁴⁶ (57, 39%).

The control group consisted of 111 term-born NBW (>36 weeks gestational age, >2500 g) from the same classrooms as the EP children (n = 93) or from other kindergarten classrooms (n = 18). To recruit controls, flyers were sent home with the students in each classroom. From the pool of students whose families responded, we recruited the classmate who most closely matched each EP child based on age at assessment, sex, and ethnicity. Controls were not recruited for children who were home-schooled or attending full-time, self-contained special education programs (n=19). Matches for the remaining 18 EP children in regular classrooms were not recruited because of school refusals, school locations too distant from the medical center, or difficulties finding matches.

There were no group differences in sex, ethnicity, or SES as defined by a mean of the sample z scores for maternal education in years, caregiver occupation (averaged for 2-parent households),⁴⁷ and median income for the neighborhood of residence based on the 2000 Census (Table 1).⁴⁸ The EP group was older than the NBW group in chronological age at school entry. However, the groups did not differ in age corrected for prematurity, as proportionally more EP children had been held back a year prior to kindergarten entry (22% vs. 3%, p<.001). Group comparisons also failed to reveal differences in age at testing, time in school when the teacher ratings were completed, or the percentage of children in full-day kindergartens (84% vs. 80%). Although a larger proportion of the EP group received early intervention services prior to school entry (83% vs. 13%, p<.001), the groups did not differ in rates of enrollment in preschool (84% vs. 85%) or daycare (49% vs. 51%).

Table 1.

Birth, Demographic, and School Entry Characteristics

Variable	EP Group (n = 148)	NBW Group (n = 111)
Birth and Neonatal Data:
Birth weight in grams, Mean (SD)a	818.37 (174.01)	3382.25 (445.86)
Gestational age in weeks (SD) a	25.85 (1.64)	>36 weeks
Multiple birth*	31 (21%)	0
Maternal Demographic Datab
Married	69 (47%)	65 (59%)
Education:
<high school	20 (14%)	14 (13%)
high school or GED	33 (22%)	16 (14%)
>high school	95 (64%)	81 (73%)
Median family income (SD)c	59.10 (32.37)	56.20 (23.67)
Child Status at School Entryd
African Americane	91 (61%)	61(55%)
Males (%)	68 (46%)	51(46%)
Age at kindergarten entry, mean years (SD)*	5.60 (.42)	5.43 (.30)
Age at testing, mean years (SD)	5.96 (.37)	5.96 (.31)
Months in school at testing*	4.25 (2.34)	6.38 (1.72)
Age at time of teacher rating of progress, mean years (SD)*	6.18 (.37)	6.03 (.31)
Months in school at teacher rating	7.16 (1.75)	7.11 (1.68)

Abbreviations: EP = extreme prematurity; NBW = term-born normal birth weight; Bayley Scales of Infant Development, 2^nd Edition Mental Development Index; ⁴⁶ GED = General Education Diploma.

^aBirth weight and gestational ages of NBW group based on maternal report; groups different by definition.

^bRefers to primary caregiver, which was the biologic or adoptive mother for 143 (97%) of the EP children and 105 (95%) of the NBW group.

^cBased on data on the neighborhood tract of the family residence from the 2000 US Census.⁴⁸ Family income is in thousands of dollars.

^dThe EP children and controls attended 113 different schools within 57 school districts located in the region surrounding Cleveland, Ohio.

^eAll others Caucasian except for 4 Asian (2 in each group).

^*Significant group difference, p<.01.

PROCEDURES AND MEASURES

Children were administered tests of achievement and cognitive ability by examiners who were blinded to their birth status while their parents completed interviews and questionnaires to obtain information about family characteristics and children’s health status. Child tests were administered in a fixed order during a single session. Six EP children were untestable on most measures due to CP and severe cognitive impairment. Scores on achievement and intelligence measures for these children and others who were too low functioning to be tested were assumed to be <85. The research was approved by the University Hospitals Case Medical Center Institutional Review Board and written informed consents from parents and teachers were obtained prior to participation.

Achievement measures included the Letter/Word Identification, Spelling, Calculation, and Applied Problems subtests of the Woodcock Johnson Tests of Achievement, 3^rd Edition.⁴⁹ To take into account time in kindergarten, the scores on these tests were based on grade rather than age standards. Test reliability for these measures is good and validity has been documented in relation to other achievement tests. IQ was estimated using the age-standardized Brief Intelligence Assessment score (BIA) from the Woodcock Johnson Tests of Cognitive Ability, 3^rd Edition.⁵⁰

Teachers provided information on special education programs as defined by an Individual Educational Plan (IEP). IEPs were identified from parent report when teacher report was unavailable. Teachers of children attending regular classrooms also reported on accommodations for learning difficulties within the classroom and completed ratings of student learning progress in each of several curricular objectives based on State of Ohio mandated goals.⁵¹ Using a previously validated method,⁵² 0 was assigned for progress toward a given objective that was behind expectations by at least a full grading period, 1 for progress that was below expectations by less than a full grading period, and 2 for progress that was at or above expectations. An advantage of these ratings over formal testing is that they provided information on children’s learning progress in specific areas of competency. Teachers were not informed of children’s birth status.

DATA ANALYSIS

Analysis of covariance (ANCOVA) was used to compare the EP and NBW groups on tests of achievement and the sum of teacher ratings of learning progress in written language and mathematics. SES, ethnicity, and sex were included as covariates. Child ethnicity was defined by caregivers and was included in analysis to control for demographic background. Preliminary analysis failed to indicate covariate by group interactions in any of the analyses, justifying exclusion of interaction terms from the models.

Logistic regression was conducted to examine group differences in learning problems as defined by standard scores <85 on the achievement tests, substandard teacher ratings of learning progress (i.e., 0 or 1), special education as defined by an IEP or related services, and any classroom accommodation. Covariates in these analyses were the same as those included in the corresponding ANCOVA. Time in school was controlled in analysis of IEPs as these placements increased during the school year.

To determine if learning deficits in the EP children could be attributed to the subset of children with CP, blindness or deafness, or low global cognitive ability as defined by BIA<85, group comparisons were repeated with these children excluded from analysis. To determine if these deficits were identifiable based on having an IEP, group comparisons were also re-run after excluding this subset of children. Associations of poor test performance and substandard learning progress with IEPs and classroom accommodations were investigated using chi-square analyses.

Associations of learning problems with neonatal risk factors, neurodevelopmental impairment at 20 months, and SES were examined using logistic regression. Each predictor was examined in a separate analysis. SES, sex, and ethnicity were covariates in analysis of the neonatal and neurodevelopmental factors.

Bonferroni-corrected alpha levels were used to determine statistical significance, with adjustments on a family-wise basis within the domains of written language and mathematics. Thus, alpha level was .05/3=.017 for each of the three primary measures within each domain (i.e., two test scores and sum of teacher ratings for the ANCOVAs; and deficits on two tests and any indication of substandard learning progress for the logistic regressions). For the sample size, power was .80 with a two-sided alpha of .05 for detecting effect sizes of .33 and differences in event rates of 15%. Differences of at least this magnitude were anticipated based on previous research with similar samples.³

RESULTS

EP children had lower scores on Spelling and Applied Problems and lower sum teacher ratings of learning progress in written language and mathematics than NBW controls (Table 2). A larger proportion of the EP group compared with NBW group was untestable or failed to reach basal levels of performance on Calculation (52% vs. 21%, p<.001). Even when excluding children with neurosensory disorders and/or BIA <85 (65 EP and 12 NBW), the EP group had lower scores on Applied Problems and lower sum teacher ratings of learning progress than the NBW group. Several of the group differences also remained significant when excluding children with IEPs.

Table 2.

Comparison of Extremely Preterm and Normal Birth Weight Groups on Measures of Achievement and Learning

	EP Group		NBW Group		F (df) from	95% CI
Domain/Measure	n	Adj M (se)	n	Adj M (se)	ANCOVA for difference
Written language:
Letter/Word Identification	142	106.07 (1.13)	111	110.05 (1.28)	5.43 (1,248)	0.61, 7.33
Spelling	140	92.09 (1.33)	111	100.61 (1.49)	18.12 (1,246)	4.58, 12.46**b
Sum of teacher ratings of learning progress in written language	110	6.74 (0.26)	106	8.94 (0.27)	34.19 (1,211)	1.45, 2.93**ab
Mathematics:
Calculation	69	102.40 (1.19)	88	105.46 (1.05)	3.72 (1,152)	−0.07, 6.19b
Applied Problems	140	95.10 (1.44)	111	106.12 (1.61)	26.95 (1,246)	6.76, 15.28**ab
Sum of teacher ratings of learning progress in mathematics	110	4.95 (0.13)	106	5.83 (0.14)	21.42 (1,211)	0.51, 1.27**ab

Abbreviations: EP = extremely preterm; NBW = term-born normal birth weight; 95% CI = 95% confidence interval for difference (adjusted mean for NBW – adjusted mean for EP); Adj M (se) = adjusted mean (standard error); ANCOVA = analyses of covariance, adjusted for socioeconomic status, ethnicity, and sex.

Note: Achievement tests are from the Woodcock Johnson Tests of Achievement, 3^rd Edition.⁴⁹ Scores reported are grade standardized to take into account the time of year when testing occurred. With exception of Calculation, on which many children were untestable, lack of child cooperation accounted for reduced sample size on the achievement tests. Reduced sample sizes for the teacher ratings were related to the procedure of collecting ratings only from teachers of regular classrooms and a small number of teacher or school refusals.

^aSignificant when excluding children with neurosensory disorders and/or a Brief Intelligence Assessment (BIA) <85 on the Woodcock Johnson Tests of Cognitive Abilities, 3^rd Edition.⁵⁰

^bSignificant when excluding children with individual educational plans.

^**Bonferroni – adjusted p<.01.

Consistent with these results, the EP group had higher rates of poor test performance on Spelling and Applied Problems, substandard teacher ratings of learning progress, IEPs, and classroom accommodations (Table 3). Several group differences remained significant in analyses that excluded children with neurosensory deficits and/or BIA<85 or those with IEPs.

Table 3.

Comparison of Extremely Preterm and Normal Birth Weight Groups on Rates of Learning Problems, Individual Education Plans, and Classroom Accommodations

Outcome	EP Group No. (%)	NBW Group No. (%)	Adjusted OR (95% CI)
Deficit in written language:
Letter/Word Identification <85	15/146 (10)	4/111 (4)	2.84 (0.90, 9.01)
Spelling <85	48/145 (33)	10/111 (9)	5.43 (2.49, 11.86)*
0 or 1 teacher ratings of progress in written language:
Identifies letter names	32/110 (29)	5/106 (5)	8.21 (3.01, 22.41)**ab
Identifies letter sounds	43/110 (39)	15/106 (14)	3.88 (1.95, 7.70) **b
Identifies number of sounds in short words	58/110 (53)	25/106 (24)	3.65 (1.98, 6.73)**ab
Answers questions about what has been read out loud to child	45/109 (41)	14/106 (13)	4.73 (2.33, 9.59)**ab
Applies letter-sound correspond-dences to spell words	62/110 (56)	22/106 (21)	5.12 (2.73, 9.60)**ab
Any 0 or 1 teacher rating	69/110 (63)	31/106 (29)	4.23 (2.32, 7.73)**ab
Deficit in mathematics:
Calculation <85	20/85 (24)	9/89 (10)	2.68 (1.12, 6.45)
Applied Problems <85	50/144 (35)	12/111 (11)	4.67 (2.24, 9.73)**
0 or 1 teacher rating of progress in mathematics:
Names numeral 1–10	26/110 (24)	4/105 (4)	7.97 (2.63, 24.11)**ab
Counts objects 1–10 with 1-1 correspondence	26/110 (24)	3/106 (3)	10.29 (3.00, 35.31)**
Matches numerals with set of objects 1–10	31/110 (28)	5/106 (5)	7.76 (2.86, 21.08)**ab
Any 0 or 1 teacher rating	33/110 (30)	6/106 (6)	7.08 (2.79, 17.95)**ab
Individual education plan (IEP)c	61/147 (41)	12/111 (11)	4.53 (2.16, 9.47)**a
Classroom accommodationd	64/109 (59)	31/107 (29)	3.53 (1.95, 6.37)**a

Abbreviations: EP: extremely preterm; NBW: term-born normal birth weight; OR (95% CI) = odds ratio (95% confidence interval) as obtained from logistic regression. ORs are adjusted for socioeconomic status, ethnicity, and sex and reflect an increase in the likelihood of deficit in EP children vs. NBW controls.

Note: Achievement tests are from the Woodcock Johnson Tests of Achievement, 3^rd Edition.⁴⁹ <85 signifies standard scores more than 1 standard deviation below kindergarten standards and takes into account time of year when testing occurred.

^aSignificant when excluding children with neurosensory disorders and/or a Brief Intelligence Assessment (BIA) <85.

^bSignificant when excluding children with IEPs.

^cIEP classifications included Specific Learning Disability (23 EP, 4 NBW), Speech or Language Impairment (19 EP, 6 NBW), Other Health Impaired (3 EP), Multiple Disabilities (5 EP), Preschooler with Disability (3 EP), Autism (1 EP), Mental Retardation (1 EP), Orthopedic Impairment (2 EP), Hearing Impairment (1 EP), Visual Impairment (1 EP), Emotional Disturbance (1 NBW), and Related Services (1 NBW). The classification for two EP children could not be determined, one because of inadequate information and a second because of placement in a private school for children with special needs.

^dThe EP group also had significantly higher rates of each type of accommodation, including reduced assignments, alternative ways of testing, individual assistance from an adult besides the teacher, different grading criteria, individual teaching or modified instructions, and classroom modifications such as special seating.

^**Bonferroni-adjusted p<.01.

Children with IEPs and classroom accommodations had higher rates of poor test performance on all achievement tests and of substandard learning progress in both written language and mathematics (all p’s<.05). However, 26 of 70 EP children (37%) with a score <85 on one or more of the achievement tests did not have an IEP. Low-achieving EP children were less likely to have an IEP if they had normal neurosensory status and BIA ≥85 (n = 14, 28%) than a neurosensory deficit and/or BIA <85 (n = 12, 60%, p = .012). Low-achieving EP children without an IEP also had significantly higher scores on Spelling and Applied Problems and lower rates of gestation <25 weeks, abnormal ultrasounds, and neurodevelopment impairment at 20 months than those with an IEP.

Within the EP group, neonatal risk factors, neurodevelopment impairment at 20 months, and SES were associated with learning problems (Table 4). Gestation <25 weeks and bronchopulmonary dysplasia were associated with higher rates of IEPs and accommodations even when children with neurodevelopmental impairment at 20 months were excluded from analysis.

Table 4.

Neonatal and Early Childhood Risk Factors Significantly Related to Learning Problems in Extremely Preterm Group

Learning Problem	Risk Factor	Risk Present No. (%)	Risk Absent No. (%)	Adjusted OR (95% CI)
Letter/Word Identification <85:	NDIa	11/58 (19)	3/85 (4)	5.90 (1.48, 23.44)*
	AbnUS	4/15 (27)	11/131 (8)	6.18 (1.45, 26.36)*
Spelling <85:	NDI	33/57 (58)	14/85 (16)	5.88 (2.55, 13.55)**
	AbnUS	8/15 (53)	40/130 (31)	6.79 (1.60, 28.69)*
	SESb			0.40 (.68, .24)**
0 or 1 teacher ratings of progress in written language:	SES			0.44 (.69, .28)**
Calculation <85:	NDI	17/30 (57)	3/54 (6)	29.06 (6.14, 137.54)**
Applied Problems <85:	NDI	33/57 (58)	14/84 (17)	5.48 (2.40, 12.53)**
	AbnUS	8/15 (53)	42/129 (33)	6.61 (1.55, 28.23)*
	SES			0.39 (.66, .23)**
Individual education plan (IEP):	NDI	40/59 (68)	19/85 (22)	6.82 (2.56, 18.16)**
	AbnUS	11/15 (73)	50/132 (38)	21.42 (2.67, 171.89)**
	BPD	40/77 (52)	21/69 (30)	2.71 (1.14, 6.45)*c
	NI	31/60 (52)	30/87 (34)	2.62 (1.07, 6.40)*
	GA<25 weeks	23/32 (72)	38/115 (33)	5.49 (1.89, 15.95)**c
	SES			0.62 (.97, .40)*
Classroom accommodation:d	NDI	33/42 (79)	30/65 (46)	4.15 (1.57, 11.02)**
	BPD	38/54 (70)	25/54 (46)	2.77 (1.19, 6.49)*c
	GA<25 weeks	18/23 (78)	46/86 (53)	3.20 (1.00, 10.21)*c
	SES			0.63 (.93, .43)*

Abbreviations: EP: extremely preterm; OR (95% CI) = odds ratio (95% confidence interval) as obtained from logistic regression; SES = socioeconomic status. ORs are adjusted for SES, ethnicity, and sex and reflect an increase in the odds of the specified learning problem with the risk factor being present; NDI = neurodevelopmental impairment as defined by a neurosensory disorder and/or Mental Development Index <70 on the Bayley Scales of Infant Development, 2^nd Edition at 20 months corrected age;⁴⁶ AbnUS = abnormal cranial ultrasound; BPD = bronchopulmonary dysplasia; NI = neonatal infection; GA = gestational age.

Note: Achievement tests are from the Woodcock Johnson Tests of Achievement, 3^rd Edition.⁴⁹ <85 signifies standard scores more than 1 standard deviation below kindergarten standards, taking into account the number of months a child is in kindergarten.

^aData missing for 3 children in group with EP.

^bORs for SES reflect a decrease in the odds of the specified learning problem given a 1 SD increase in SES.

^cSignificant when excluding children with NDI.

^dClassroom accommodations include reduced assignments, ways of testing, individual assistance from an adult besides the teacher, different grading criteria, individual teaching or modified instructions, and classroom modifications such as special seating.

^*Bonferroni-adjusted p<.05;

^**Bonferroni-adjusted p<.01.

COMMENT

Current survival of EP children has reached a level previously unsurpassed but with high rates of neonatal morbidity.⁵³ As increasing numbers of these children are reaching school age, it is critical that we identify the problems they have at school entry and factors related to early educational difficulties. Our results reveal that the EP children performed more poorly on achievement tests, were making less learning progress, and had higher rates of IEPs and classroom accommodations than NBW controls. Academic problems were evident on tests of written expression and mathematics and in teacher ratings of learning progress in these areas. A recent report of academic outcomes in 6-year-olds of ≤33 weeks gestation born in the 1990s indicated higher rates of academic problems compared with NBW controls even for the subset of EP children without neurosensory deficits or low global cognitive ability.²⁰ Our results suggest similar outcomes for children born in the 2000s. Although other studies have reported deficiencies in academic readiness or beginning achievement skills in preterm children,^{12,18,20,21,23,54,55} to our knowledge this is the first study to demonstrate the pervasiveness of learning deficiencies during the first year in school among EP children born since 2000. Because the EP and NBW groups were similar in sociodemographic characteristics, neonatal brain insults and subsequent abnormalities in neural development may contribute in large part to their higher rates of educational difficulties.^56,57

This study is also among the first to examine educational interventions for EP children in kindergarten and the correspondence of these interventions with learning problems. More EP children than NBW controls were receiving special assistance at school, yet many EP children with low scores on an achievement test did not have an IEP. Low-achieving EP children without an IEP had higher achievement scores and lower rates of neurosensory deficit, low cognitive ability, and neonatal complications than those with an IEP, suggesting that children with less severe impairments are more likely to be under-identified. It is also possible that IEPs had not been completed for some children despite parent or teacher awareness of learning difficulties. Our results imply that the educational needs of EP children are not fully met.

Achievement deficits in the EP group were evident in mathematics and spelling but not in word recognition. When children with neurosensory deficits or low global cognitive ability were excluded from analysis, only the deficit in mathematics problem solving remained significant. These findings are consistent with other data indicating that problems among preterm children in mathematics are more prominent and selective than problems in reading.^{1,6,20,35,58–60}

Neonatal risk factors associated with learning problems of EP children in kindergarten included gestation <25 weeks, abnormal cranial ultrasounds, bronchopulmonary dysplasia, and infection. Neurodevelopmental impairment at 20 months and lower SES also predicted learning problems. Previous studies have reported similar risks for deficits in school readiness skills and special education interventions.^{3,18,19,31,32,34,36,37,39–43,61,62} These risk factors may thus have utility in identifying the children most deserving of developmental monitoring and early childhood interventions prior to school entry.

A limitation of this study was that teacher ratings of educational progress were only obtained for EP children attending regular classrooms. This procedure was warranted to insure that expectations for progress could be judged relative to the general kindergarten population but is likely to have underestimated the effect of EP on learning progress. A further limitation is that information on IEPs was provided by teachers and parents and we had no means to determine the extent to which these plans were implemented or addressed the children’s learning problems. Our EP cohort was hospital-based and we were unable to follow 25% of the families. The sample was predominantly urban and African American and, although largely reflective of EP births within the region, not representative of the U.S. as a whole. Educational interventions may also vary from those provided elsewhere in the U.S. Because of privacy issues parents of NBW children were selected from among those who agreed to be contacted, introducing possible bias in selection of controls. However, the children attended a multitude of schools throughout the region, there were no differences in background factors between participants and non-participants or between the EP and NBW groups, and our results are similar to previous reports of early educational outcomes.^20,21,30

Although poorer reading skills in older school-age children are associated with reduced cerebellar volume and mathematics difficulties with reduced gray matter in the left parietal lobe,^63,64 further studies are need to investigate the neural basis of early academic difficulties in EP children and examine the cognitive and behavior problems associates with these difficulties. Deficits in specific skill areas, such as processing speed and working memory, may be closely related to academic difficulties, with different patterns of association for reading and mathematics disabilities.^11,59,65 Additional study of environmental influences on academic achievement at school entry is also needed to identify characteristics of families and schools that buffer or exacerbate early learning progress.^29,66

In conclusion, our findings reveal high rates of learning problems and special learning interventions in EP children at the time of school entry, as well as associations of these outcomes with neonatal risk factors and neurodevelopmental impairment at 20 months. The findings also underscore the fact that many EP children with learning problems in kindergarten are not receiving special interventions, and they show that teacher ratings of learning progress hold promise as a simple and effective means to screen for these problems. Efforts to minimize the adverse effects of EP on later academic achievement may need to include more extensive developmental and educational interventions beginning in kindergarten or earlier.^{18–21,25–27} A system of follow-up care that provides ongoing monitoring of children’s status and needs from birth through school age, such as a “medical home,” may be especially helpful in insuring early detection and intervention.²⁶