Stability of the mental and motor Bayley scales of Infant Development (2nd ed.) in infant over first three years of life - Epidemiological Review

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ABSTRACT

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the first three years of life.

0$7(5,$/$1'0(7+2'6 All children included in this study were a sample followed up in a study on the

VXVFHSWLELOLW\RIWKHIHWXVDQGFKLOGWRHQYLURQPHQWDOIDFWRUV7KHFRKRUWUHFUXLWHGSUHQDWDOO\LQ.UDNRZ3RODQG LQFOXGHGFKLOGUHQ7KHPHQWDODQGPRWRUVFDOHVRI%6,',,ZHUHDGPLQLVWHUHGWRLQIDQWVDWWKHHQGRIthth

and 36thPRQWKRIOLIH6WDELOLW\RIWKHWHVWVFRUHVIURPILUVWWRVHFRQGDQGWKLUGDVVHVVPHQWZDVHYDOXDWHGXVLQJ

the Pearson’s correlation coefficient calculated for the entire group of infants, and for the each gender separately.

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.H\ZRUGV: child development, Bayley Scales of Infant Development, outcomes stability $%%5(9,$7,216: BSID-II – Bayley Scales of Infant

'HYHORSPHQWnd _ed.

MDI - Mental Developmental Index, PDI - Psychomotor Developmental Index

INTRODUCTION

Bayley Scales of Infant Development second edition %6,',,KDYHEHHQFRQVLGHUHGWKHFULWHULRQVWDQGDUG IRUWKHGHYHORSPHQWDODVVHVVPHQWRILQIDQWVDQGVXEVH-quent diagnosis of cognitive or motor delays. BSID-II KDYHEHHQXVHGDVDJROGVWDQGDUGWRHYDOXDWHWKHRWKHU tools of assessment of infants development (1). Bayley HYDOXDWLQJ%6,',,KDVHVWDEOLVKHGWHVWUHWHVWVWDELOLW\ LQWKHVWDQGDUGL]DWLRQVDPSOHDQGPRQWKV 7KHLQWHUYDOEHWZHHQWKHWZRWHVWVUDQJHGIURPWR GD\V7KHVWDELOLW\FRHIILFLHQWVIRUERWKWHVWVZHUHKLJK DQGFRQILUPHGWKHKLJKUHOLDELOLW\RI%6,',,'H-VSLWHLWVZLGHXVHERWKFOLQLFDOO\DQGLQUHVHDUFKVHWWLQJV RQO\DIHZVWXGLHVZHUHSXEOLVKHGWKDWKDYHH[DPLQHG WKH VWDELOLW\ RI %6,',, RXWFRPHV RYHU WLPH7KHVH VWXGLHVZKLFKKDYHEHHQPRVWO\UHODWHGWRKLJKULVN infants with multiple medical conditions have revealed ORZRUPRGHUDWHVWDELOLW\RI%6,',,VFRUHVRYHUWLPH 7KHHYDOXDWLRQDWHVWUHWHVWVWDELOLW\RI%6,',,XVLQJ longer intervals measured the predictive value of the early tests for the future outcomes (3). Ideally, studies WKDWH[DPLQHVWDELOLW\RIWHVWVFRUHVW\SLFDOO\VKRXOGXVH KHWHURJHQHRXVJURXSV7KHUHLVLPSRUWDQWWRHVWDEOLVK XWLOLW\RIWKHVLQJOH%6,',,RXWFRPHVREWDLQHGLQFHU-tain time of infant life for the development outcomes in IXWXUHERWKLQWKHKLJKULVNDQGWKHORZULVNLQIDQWV

7KHDLPRIWKLVVWXG\ZDVWRH[DPLQHWKHVWDELOLW\ of BSID-II scores during the first three years of life in infants from general population, included mostly the

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ORZULVNLQIDQWVDQGWRHVWDEOLVKFOLQLFDOXWLOLW\RIWKH single BSID-II outcomes for prediction of children development in future.

MATERIAL AND METHODS

All children included in this study were a sample IROORZHGXSLQDFROODERUDWLYHVWXG\ZLWK&ROXPELD 8QLYHUVLW\LQ1HZ<RUNRQWKHVXVFHSWLELOLW\RIWKHIHWXV and child to environmental factors. The cohort recruited prenatally in Krakow Poland, included the children of QRQVPRNLQJZRPHQDJHGWR\HDUVZLWKVLQJOHWRQ pregnancies, who had lived in Krakow for at least one year prior pregnancy. Mothers were free from chronic diseases, HIV infection and illicit drug use. The study SRSXODWLRQLQFOXGHGFKLOGUHQ'HVSLWH%6,',,FRP-prises three scales, only the Mental and Motor Scales ZHUHDGPLQLVWHUHGLQWKHSUHVHQWVWXG\LQthth _and

36th _{month of life (within 4 weeks of the target age).}

The Psychomotor Scale assesses control of gross and fine muscle groups (rolling, crawling, creeping, sitting, standing, walking, running, and jumping). The Mental 6FDOHLQFOXGHVLWHPVWKDWDVVHVVPHPRU\KDELWXDWLRQ SUREOHPVROYLQJHDUO\QXPEHUFRQFHSWVJHQHUDOL]D-tion, classificaSUREOHPVROYLQJHDUO\QXPEHUFRQFHSWVJHQHUDOL]D-tion, vocalizaSUREOHPVROYLQJHDUO\QXPEHUFRQFHSWVJHQHUDOL]D-tion, language, and social skills. Test scores are adjusted for the age of the child WRREWDLQWKH3V\FKRPRWRU'HYHORSPHQW,QGH[3', and the Mental Development Index (MDI). Test results are in one of four categories: 1) accelerated performance VFRUH!ZLWKLQQRUPDOOLPLWVVFRUHWR PLOGO\GHOD\HGSHUIRUPDQFHVFRUHWRDQG VLJQLILFDQWO\GHOD\HGVFRUH

The changing over time the MDI and the PDI scores from first to second and third assessment was evaluated using the Pearson’s correlation coefficient calculated for the entire group of infants, and for the each gender separately.

RESULTS

7KHVDPSOHRIVWXG\SDUWLFLSDQWVLQFOXGHGPRVW-ly the low risk infants with characteristic typical for FKLOGUHQUHFUXLWHGIURPJHQHUDOSRSXODWLRQWDE,*LUOV KDGDVLJQLILFDQWO\KLJKHUWKH0',VFRUHVWKDQER\VLQ DOODJHJURXSV7KH3',VFRUHVDWWKHDJHRIth _and

36th _{months was also higher in girls. The older infants}

REWDLQHGWKHEHWWHURXWFRPHVLQ%6,',,WDE,,2Q the other side with increasing age there were the higher QXPEHURILQIDQWVZKRZHUHQRDEOHWRSHUIRUPWKHWHVW LQDUHDVRQRIDZHDNFRRSHUDWLRQWDE,,,7KHRE-tained outcomes divided infants into three groups. The most of infants were included within normal limit group, less to accelerated performance, and a few percent to

7DEOH, &KDUDFWHULVWLFRIWKHVWXG\JURXS Characteristic 1XPEHU % Gender Boys  50.5 Girls  49.5 Parity 1    144 35.3 Weeks of pregnancy ZHHNV 16 3.9 ZHHNV 391  !ZHHNV 1  Birth weight  11  ฀   Mothers age   19.4    30 - 34  30.9 Mothers education

primary or vocational school 39 9.6 technical college  11.5 high school or college 106 

university  

7DEOH,, %6,',,RXWFRPHVLQthth _{and 36}th _{month of}

life

Index Total Boys Girls p

Mean SD Mean SD Mean SD

0', 101.4  100.3     3',  11.41  10.61    0',   99.0 11.61 105.4   3', 99.5 9.59  9.14 101.3   MDI36 103.6  101.6 10.01    PDI36 104.4  101.9   10.11  7DEOH,,,&DWHJRU\GLVWULEXWLRQRI%6,',,RXWFRPHV The developmental category

Boys Girls Total

N % N % N % 0 ' , accelerated performance    11.4% 41 10.0% within normal limits     340  mildly delayed 16  11 5.4%   3' , accelerated performance 10 4.9% 14 6.9%  5.9% within normal limits   164    mildly delayed 13 6.3%  11.9%  9.1% 0 ' , accelerated performance   64    within normal limits 163   61.9%   mildly delayed   13 6.4% 33  3' , accelerated performance  3.4%    6.1% within normal limits  90.3%   361  mildly delayed 13 6.3% 9 4.5%  5.4% M D I36 accelerated performance   40  60  within normal limits       mildly delayed   4  16 3.9% P D I36 accelerated performance   44   16.4% within normal limits   155  331  mildly delayed  3.4% 3 1.5% 10 

Mental and motor Bayley scales of infant development  No 3 PLOGO\GHOD\HGWDE,,,7KHFRUUHODWLRQEHWZHHQWKH ILUVWDQGVHFRQGDVVHVVPHQWVIRUWKH3',ZDVU  IRUWKH0',ZDVU DQGEHWZHHQWKHVHFRQGDQG WKLUGDVVHVVPHQWVWKHFRUUHODWLRQIRUWKH3',ZDVU  IRUWKH0',ZDVU 7KH0',VFRUHVKDGWKH stronger correlation over time than the PDI score. The VWDELOLW\RIWKHWHVWVVFRUHVRYHUWLPHZDVKLJKHUIRUWKH RXWFRPHVREWDLQHGE\ROGHULQIDQWV7KDWUHVXOWVVXJ-JHVWDORZRUPRGHUDWHGHJUHHRIUHODWLRQVKLSEHWZHHQ WKHWHVWVRXWFRPHV2QO\WRRIYDULDQFHLQ WKHLQIDQWVODWHU%6,',,VFRUHVFRXOGEHH[SODLQHGE\ WKHLUHDUOLHUVFRUHVWDE,97KHFRUUHODWLRQEHWZHHQ WKHWHVWVVFRUHVZDVKLJKHUEHWZHHQRXWFRPHVREWDLQHG E\JLUOVWKDQER\VWDE9 7DEOH,9&RUUHODWLRQFRHIILFLHQWVEHWZHHQ%6,',,RXWFRPHV

Index outcomes 0', 0', MDI36

0', 1 * * 0', 1 0.590* MDI36 1 3', 3', PDI36 3', 1 * _0.161* 3', 1 0.396* PDI36 1 &RUUHODWLRQFRHI¿FLHQWVVLJQL¿FDQWELODWHUDOO\S 7DEOH9 &RUUHODWLRQFRHIILFLHQWVEHWZHHQ%6,',,RXWFRPHV LQER\VDQGJLUOV Index outcomes Boys Girls 0', 0', MDI36 0', 0', MDI36 0', 1 0.196**  _{1 0.434}** ** 0', 1 ** ₁ ** 3', 3', PDI36 3', 3', PDI36 3', 1 *** _{0.136 1 0.344}*** * 3', 1 ** ₁ ** &RUUHODWLRQFRHIILFLHQWVVLJQLILFDQWELODWHUDOO\S &RUUHODWLRQFRHIILFLHQWVVLJQLILFDQWELODWHUDOO\S DISCUSSION

The evaluation of children’s developmental prog-ress is an important part of routine pediatric care. The methods recommended as a reference tool in assessing infants development are the BSID-II and BSID-III (5). 'HVSLWHWKHKLJKUHOLDELOLW\DQGYDOLGLW\RI%6,',,WKDW KDYHEHHQHVWDEOLVKHGLQWKH86WKHUHLVVWLOOLPSRUWDQW WRHYDOXDWHDVWDELOLW\RIWKHWHVWVRXWFRPHVRYHUWLPH in different groups of infants. The low risk infants and the high risk infants with multiple medical conditions characterize different pattern of development. The dif-ferential pattern of results over time for BSID-II when XVHGZLWKPHGLFDOO\IUDJLOHLQIDQWVFRXOGEHLQWHUSUHWHG DVHYLGHQFHIRUTXHVWLRQLQJWKHYDOLGLW\RIWHVWVEXWLW

is more likely a result of group differences. Despite matching samples on primary diagnosis, age of the first assessment, age at the second assessment, gender, and geographic region in which the tests were admin-istered, groups may have differed on other factors, like SV\FKRVRFLDODQGHQYLURQPHQWDOIDFWRUVZKLFKPD\EH associated with differential developmental outcomes (6). The same factors influence children development in general population from which we derived infants for our study. Our study has confirmed the low or moder-DWHVWDELOLW\RIWKH%6,',,RXWFRPHV7KHREWDLQHG FRUUHODWLRQFRHIILFLHQWVEHWZHHQWKH3',DQGWKH0', VFRUHVRYHUWLPHFDQEHFRPSDUHGRQO\WRWKHUHVXOWV of a few previous studies which had the similar study design. There is necessary to perform the BSID-II tests in infants at the same age with the same time interval EHWZHHQUHDVVHVVPHQWVWRKDYHDSRVVLELOLW\WRFRP-pare the results. The most of previous studies started to perform the initial tests in younger infants than in our VWXG\EXWILQLVKHGWKHDVVHVVPHQWHDUOLHUQHDUO\DWWKH HQGRIWKHVHFRQG\HDURIOLIH7KHFRUUHODWLRQEHWZHHQ WKHILUVWDQGVHFRQGDVVHVVPHQWVIRUWKH3',U  DQGIRUWKH0',U LQRXUJURXSRILQIDQWVZDV somewhat weaker than in other studies, which assessed PRUHKRPRJHQRXVJURXSVFRPSDUHGWRRXULQIDQWV In the other studies participants were divided into groups of low risk and high risk infants and among the second group infants were matched to samples with primary diagnosis. In homogenous samples of infants WKHSDWWHUQRIGHYHORSPHQWZDVPRUHVWDEOHWKDQLQKHW-HURJHQHRXVJURXS:HKDGPDQ\LQIRUPDWLRQDERXW LQIDQWVJLYLQJWKHSRVVLELOLW\RIGLYLVLRQRXUJURXSLQWR WKHORZULVNDQGWKHKLJKULVNVDPSOHEXWWKHUHZHUHWRR VPDOOQXPEHURILQIDQWVZKRFRXOGEHLQFOXGHGWRWKH KLJKULVNVDPSOHWKDQZHDVVHVVHGWKHVWDELOLW\RIWKH BSID-II for entire group without any exclusions. The KHWHURJHQHLW\RIRXUJURXSRILQIDQWVLVSUREDEO\WKH UHDVRQRIWKHORZHUVWDELOLW\RIWKH%6,',,FRPSDUHG WRWKHUHVXOWVRIWKHRWKHUVWXGLHV&OHDUO\WKH length of the interim period was closely related to the strength of the correlation: the longer the interval, the lower the correlation. Furthermore, independently of the length of the interim period, the correlation coef-ficients were higher for older infants and for the MDI comparing to the PDI scores. There is no information in SUHYLRXVVWXGLHVDERXWVWDELOLW\RIWKH%6,',,LQJHQGHU JURXSV2XUVWXG\UHYHDOHGWKHKLJKHUVWDELOLW\RIWKH BSID-II in girls. It confirmed the differential pattern RIGHYHORSPHQWEHWZHHQJHQGHUV7KHDGYDQWDJH of performing this study in older group of infants is SRVVLELOLW\WRHYDOXDWHWKH%6,',,VWDELOLW\LQSHULRG ZKLFKZDVPLVVHGLQPRVWSUHYLRXVVWXG\GHVLJQ 7KHJUHDWHUVWDELOLW\RIWKH%6,',,LQROGHULQIDQWVWKH more difficulties in performing the tests for a reason of

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tion concerned mostly infants with lower BSID-II scores EXWKDSSHQHGWRLQIDQWVZKRSHUIRUPHGWKHHDUOLHUWHVWV YHU\ZHOOWRR7KDWSUREOHPGLGQRWRFFXULQWKH\RXQJ-est infants. The weak cooperation in a few percent of three years old infants decreases the clinical utility of the BSID-II in that group of age.

The advantage of our study comparing to the previ-ous studies is a large group of infants derived not from VSHFLILFSRSXODWLRQEXWIURPJHQHUDOSRSXODWLRQZKR were assessed in relatively older age. The most impor-tant advantage in comparison with previous studies is WKHXVLQJWKHVDPHWLPHLQWHUYDOEHWZHHQUHDVVHVVPHQWV ZKDWDOORZHGWRHVWDEOLVKDSUHFLVHGLIIHUHQFHEHWZHHQ VWDELOLW\RI%6,',,LQGLIIHUHQWDJH,QRXUVWXG\ZH HYDOXDWHGWKHVWDELOLW\RI%6,',,IRUER\VDQGJLUOV separately and we revealed a significant difference of WKH%6,',,VWDELOLW\GHSHQGHGRQJHQGHU)XUWKHUPRUH we have many information on additional maternal and environmental risk factors which may affect the BSID-,,VFRUHV)RUH[DPSOHLQRXUVWXG\ZHHVWDEOLVKHGWKH parents educational level as a most significant factor that influenced the infants development.

Despite some limitations, our study confirmed the previous results that for infants who had completed the %6,',,WKHFRUUHODWLRQVEHWZHHQVFRUHVLQILUVWDQG second or third year of life indicated a moderate level of systematic change in children development. The developmental delays identified in the end of the first \HDUZLWK%6,',,PD\LQGLFDWHDPRGHUDWHSUREDELOLW\ of continuing delays, the same relationship concerns infants within normal limits who may change their clas-sification group of the developmental level. Infants from general population characterize a trend of acceleration the development in the second and the third year of life. While the BSID-II as a measure of infant develop-PHQWPD\EHDYDOLGDQGXVHIXOLQGLFDWRURIFXUUHQW IXQFWLRQLQJVFRUHVIRUVRPHLQIDQWVPD\QRWEHVWDEOH IURPILUVWWRVHFRQGDQGWKLUG\HDURIOLIH7KHLQVWDELOLW\ in scores are due to the nature of infants development rather than deficiencies in the test (10). These findings have clinical implications and are directly relevant to assessment policies and practices in infant development programs. They confirm cautious interpretation of as-sessments conducted in the early infancy. The results from BSID-II assessments of infants in the first year RIOLIHVKRXOGQRWEHXVHGIRUSUHGLFWLYHSXUSRVHVDQG PXVWEHLQWHUSUHWHGGLIIHUHQWO\IRULQGLYLGXDOLQIDQWV considering specific medical conditions and the other factors which can influence infants development (5).

CONCLUSION

7KH%6,',,VKRXOGQRWEHWUHDWHGDVDXVHIXOPHD-sure for predictive purposes of infants development.

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This is a part of ongoing comparative longitudinal study on the health impact of prenatal exposure of infants and children WRRXWGRRULQGRRUDLUSROOXWLRQZKLFKLVEHLQJFRQGXFWHGLQ the New York City and Krakow. The study received funding IURPDQ52JUDQWHQWLWOHG³9XOQHUDELOLW\RIWKH)HWXV,QIDQWV to PAH, PM_DQG(76´52(61,(+6 - 01/31/04) and from NIEHS (5 RO1 ES010165-0451), the Lundin Foundation, and the Gladys T. and Roland Harriman Foundation. Principal Investigator: Prof. F.P. Perera

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