Cerebral palsy in children: Movements and postures during early infancy, dependent on preterm vs. full term birth

Abstract

Background

A deviant motor behaviour at age 3 to 5 months is predictive of cerebral palsy (CP). Particular features of the early motor repertoire even proved predictive of the degree of functional limitations as classified on the Gross Motor Function Classification System (GMFCS) in children with CP, born preterm.

Aims

We aimed to determine whether an association between the early motor repertoire and the GMFCS also holds true for children born at term.

Study design

Longitudinal study.

Subjects

79 infants (60 boys and 19 girls; 47 infants born at term; video recorded for the assessment of movements and posture at age 9 to 20 weeks postterm age) who developed CP.

Outcome measures

The GMFCS was applied at age 2 to 5 years.

Results

Motor optimality at age 3 to 5 months showed a significant correlation with functional mobility and activity limitation as classified on the GMFCS at age 2 to 5 years in both children born at term (Spearman rho = − 0.66, p < 0.001) and born preterm (rho = − 0.37, p < 0.05). Infants born preterm were more likely to show normal movement patterns than infants born at term. A normal posture and an abnormal, jerky (yet not monotonous) movement character resulted in better levels of function and mobility. With the exception of one, none of the infants showed fidgety movements. A cramped-synchronised movement character, repetitive opening and closing of the mouth, and abnormal finger postures characterised children who would show a poor self-mobility later.

Conclusions

Assessing the quality of motor performance at 9 to 20 weeks postterm age (irrespective of the gestational age) improves our ability to predict later functional limitations in children with CP.

Introduction

Cerebral palsy (CP) is a well-recognized neurodevelopmental condition which manifests early in childhood, usually before 18 months of age [1]. A comprehensive meta-analysis revealed that the prevalence of CP decreases with increasing gestational age: 14.6% of affected children were born extremely preterm (below 28 weeks' gestational age), 6.2% between 28 and 31 weeks' gestation, 0.4% to 0.7% were born moderately preterm (i.e. at 32 to 36 weeks' gestation), and 0.1% at term [2]. In children born preterm, spastic CP is predominant, whereas in children born at term dyskinetic and ataxic forms prevail [2]. Bilateral spastic CP is more widespread than unilateral spastic CP both in infants born preterm (median prevalence: 73% vs. 21%) and born at term (median prevalence 48.5% vs. 36.5%) [2]. Figures show a similar prevalence of CP in China as in Europe or the USA [3], [4].

Apart from the low gestational age and low birth weight, perinatal asphyxia, white matter disease, severe intraventricular haemorrhage, cerebral infarction and deep grey matter lesions were identified as predictors of CP [4], [5], [6]. Abnormal spontaneous ‘general movements’ (GMs) were found to be among the most reliable markers for CP [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17]. The assessment of GMs is based on visual Gestalt perception in preterm infants and term infants aged up to 5 months. Normally, GMs comprise the entire body and manifest themselves in variable sequences of arm, leg, neck and trunk movements. They come and go gradually, varying in intensity and speed. Rotations and frequent slight variations of the direction of motion make them look complex, though smooth [13]. GMs occur in age-specific patterns. During the postterm age of 3 to 5 months, they are described as ‘fidgety movements’, i.e. small movements of the neck, trunk and limbs in all directions and of variable acceleration [7]. Virtually all infants develop normally if such fidgety GMs are present and normal, even if their brain ultrasound findings indicate a disposition to later neurological deficits. Conversely, almost all infants with no fidgety movements develop neurological deficits, even if their ultrasound indicates no significant risk [7], [13]. A recent review of 15 studies on the predictive value of fidgety movements reported a sensitivity > 91% and a specificity > 81% [18]. The most comprehensive study so far, in which more than 900 children participated, yielded a sensitivity of 98% and a specificity of 94% [19].

The motor repertoire of infants aged 3 to 5 months consists not only of fidgety movements but also of other movements and postural patterns [20]. Detailed studies have shown that several qualitative and quantitative aspects of the motor patterns are predictive of the level of self-mobility of children with CP [16], as well as of minor neurological dysfunctions [21], [22], [23], and lower intelligence at school age [24]. Bruggink and colleagues [16] found a non-optimal motor behaviour at 11 to 17 weeks to be indicative of poor self-mobility in 37 children with CP (9 unilateral spastic CP and 28 bilateral spastic CP). Apart from the absence of fidgety movements, more severe functional limitations in 6- to 12-year-old children with CP were mainly associated with a cramped movement character, an age-inadequate motor repertoire, and monotonous kicking [16]. Interestingly enough, the same study demonstrated that a so-called flat posture (i.e. all limbs were mainly lying on the surface; antigravity movements and flexions in hips and knees were rare) was associated with a less severe functional limitation [16]. However, the sample of 37 children only included preterm infants born before 34 weeks' gestation, which raised the question of whether such a detailed analysis of movements and postures in infants (aged 3 to 5 months) could also be predictive of the functional mobility of children with CP who were born at term. We therefore did the same assessment both in term-born and in preterm-born children with CP. The aims of our study were (1) to describe movements and postures in 9- to 20-week-old infants who later developed CP; (2) to analyse to what extent the motor performance at 9 to 20 weeks' postterm age was related to (a) the anatomical (uni- vs. bilateral) distribution of CP and (b) the functional mobility and activity limitation at 2 to 5 years of age as classified on the Gross Motor Function Classification System (GMFCS) [25]; and (3) to analyse whether such associations are different in term-born children with CP and preterm-born children with CP.