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200年1月4日一项新的研究表明，在极低出生体重婴儿中（出生时体重低于1500克）脑瘫的发病率正在下降。这是迄今为止同类研究中最全面的一次，来自英国利物浦大学的研究者们对欧洲16个脑瘫登记协作处的数据进行了统计，发现极低出生体重婴儿的脑瘫发病率显著下降，在1980年每一千个存活儿中患病例为60.6例，而到1996年则下降至39.5例。而且这种下降是由双侧痉挛性脑瘫发病率减少导致的。“其中最大的一个问题，就是极低出生体重婴儿围产期死亡率的下降是否会以发生脑瘫的巨大风险为代价。幸好，我们已经证明在这些儿童中脑瘫发病率有着显著的下降，从而让他们能避免神经系统损伤而更好的存活下来。”这项研究的主要负责人 Mary Jane Platt博士告诉记者说。这项研究发表在1月6号出版的《柳叶刀》杂志上。

数据采集

作为知名的脑瘫监测组织，欧洲脑瘫登记协作网成立于1998年，同时对脑瘫的确切定义和患儿的症状描述进行了规范化。以前曾有小范围的研究表明极低出生体重婴儿的脑瘫发病率可能在下降，目前的研究则是第一次借助了统计学方法来精确阐明发病趋势。“尽管极低出生体重婴儿的数量在增加，但还不是很大的数目，因此仅以这一数目来研究脑瘫发病趋势是比较困难的。而将16个登记处的数据联合起来则提供了相当充足的样本量，以便使我们能探索在一定时期内（极低出生体重婴儿）脑瘫发病率是否有一些发展趋势。” Platt博士介绍说。这项研究采用了16个协作中心登记的欧洲9个国家从1980至1996年出生的婴儿数据，这些婴儿的出生体重都是记录过的。为保证临床诊断的精确程度，这些数据在加入脑瘫监测数据库中时患儿至少已经4岁了。这些婴儿的母亲人口统计学特征以及婴儿性别、体重、出生时胎龄都被记录下来，而且关于是否多胎妊娠以及脑瘫类型的信息也被记录在案，同时还记录有每个儿童的各项体征，包括智力、视力、听力以及行走能力。

恰当护理

在这项研究所包含的时间段内，一共有7884名脑瘫患儿出生。其中，2103名出生时体重不到1500克或者出生时胎龄不足32周，这些患儿正是要研究的对象。研究者发现在所有登记协作中心，极低出生体重婴儿在存活婴儿中所占比率均提高了。且在瑞典和英国较为显著，从1980年的0.5%提高至1996年的1%。在研究的时间段内，极低出生体重婴儿的脑瘫发病率显著下降。然而，在出生时体重不足1000克的患儿中，17年间发病率却没有显著的变化。此外，作者认为，出生体重不到1000克的婴儿和出生体重介于1000～1499克的婴儿患单侧痉挛性脑瘫的几率相当。然而这项研究并不是用来解释极低出生体重婴儿的脑瘫发病率下降的原因，Platt博士认为研究结果表明这些患儿得到了恰当的照料。“将发病率下降归结为某个特定原因是很困难的，如，我们不清楚给氧以及不给氧的婴儿脑瘫发病率。然而，发病率下降的研究结果让我们确信现在给予患儿的照料是恰当的。”Platt博士总结说。

预防早产

在相关的评论中，来自克理夫兰西部病例管理大学的Maureen Hack以及Deanne Wilson Costello博士认为，研究所揭示的成果是鼓舞人心的，然而还需要进一步深入研究。“脑瘫伴随着较多的残疾：欧洲脑瘫监测组织的统计表明，35.2%的双侧痉挛性脑瘫患儿无法行走，23.5%的患儿有重度精神发育迟缓症状。此外，来自欧洲脑瘫监测组织及美国的数据均显示存活婴儿中极低出生体重婴儿数量的增长，这可能导致脑瘫患儿的增多。因此，必须加强对早产以及相关脑部损伤的预防。”评论中写道。

Cerebral Palsy Declines Among Very-Low-Birth-Weight Infants

Caroline Cassels

January 4， 2007 — The prevalence of cerebral palsy (CP) among very-low-birth-weight (VLBW) infants — those born weighing less than 1500 g — is declining， a new study suggests.

In the largest study of its kind to date， researchers at Liverpool University， in the United Kingdom， pooled data from 16 European CP registries and found a significant fall in the prevalence of CP in VLBW infants， from 60.6 per 1000 live births in 1980 to 39.5 per 1000 live births in 1996. Furthermore， this decline was attributed to a reduction in the bilateral subtype of CP.

"One of the big questions is whether the improved perinatal mortality of low-birth-weight babies comes at the expense of a greater risk of cerebral palsy. However， we have demonstrated a significant fall in the rates of cerebral palsy in these children， which suggests they now have a better chance of survival without severe neurological impairment，" the study's principal investigator， Mary Jane Platt， MD， told Medscape.

The study is published in the January 6 issue of the Lancet.

Strength In Numbers

Collectively known as the Surveillance of Cerebral Palsy in Europe (SCPE)， the network of CP registries was established in 1998 and has standardized definitions of CP as well as agreed definitions and descriptions of affected children.

While previous， smaller studies have suggested that CP may be declining in VLBW children， this study is the first with the statistical power to accurately detect prevalence trends.

"Although the numbers of very-low-birth-weight infants are increasing， there still aren't large numbers of these children， so it is difficult to look at CP trends in this population. The opportunity derived from 16 groups working together provided us with a large enough pool of [VLBW] children to determine whether there were any trends in terms of the prevalence of cerebral palsy over an extended period of time，" said Dr. Platt

The study included children from 16 centers in 9 European countries born between 1980 and 1996 with known birth weight. To ensure accurate clinical assessment， affected children were at least 4 years old at the time of inclusion in the SCPE database.

Demographic characteristics of the mother and the sex， weight， and gestational age at birth of the child were recorded. In addition， information about whether the child was from a multiple pregnancy and the neurological subtype of CP， as well as measurements of each child's function， including IQ， ability to walk， vision， and hearing， were gathered.

Appropriate Care

A total of 7884 children with CP were born during the study period. Of these， 2103 had a birth weight of less than 1500 g or had a gestational age of less than 32 weeks at the time of birth and constituted the study population.

The investigators found that in all centers the proportion of VLBW children among live births increased. This increase was most pronounced in Sweden and the United Kingdom， where it increased from 0.5% in 1980 to almost 1% in 1996.

There was a significant fall in the prevalence of CP among VLBW babies over the study period. However， in children with birth weights of less than 1000 g， there was no significant change in the prevalence over the 17-year study period.

Furthermore， the authors report， rates of unilateral spastic CP were similar in children with birth weights of less than 1000 g and those between 1000 and 1499 g.

While the study was not designed to elucidate why CP rates are dropping in VLBW infants， Dr. Platt said the study results suggest that these children are receiving appropriate care.

"It is very difficult to attribute this decline to anything specific. For instance， we don't know what the rate of cerebral palsy is among children who are ventilated vs the rate in those who are not. However， the fact that the study shows rates of CP are declining gives us confidence that the care these babies are receiving is appropriate，" said Dr. Platt.

Preventing Preterm Birth

In an accompanying editorial， Maureen Hack， MD， and Deanne Wilson Costello， MD， from Case Western Reserve University， in Cleveland， Ohio， write that while the decrease in CP revealed by the study is "encouraging，" there is still a long way to go.

"Cerebral palsy is associated with major disabilities: in the SCPE study， 35.2% of the children with bilateral spastic cerebral palsy were unable to walk and 23.5% of children had severe mental retardation. Furthermore， both the SCPE study and data from the [United States] have recorded an increase in the number of live births of very low birth weight， which might lead to an increase in the number of children with cerebral palsy. Therefore， every effort needs to be invested in the prevention of preterm birth and its associated brain injury，" they write.

Lancet. 2007;369:7-8， 43-50.

http://www.medscape.com/viewarticle/550303

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