Specific characteristics of spontaneous movements in preterm infants at term age are associated with developmental delays at age 3 years

Authors


Correspondence to Professor Gentaro Taga, Department of Physical and Health Education, Graduate School of Education, University of Tokyo, 7–3–1, Hongo, Bunkyo-ku, Tokyo 113–0033, Japan. E-mail: taga@p.u-tokyo.ac.jp

Abstract

Aim

The aim of this study was to investigate the relationship between the characteristics of spontaneous movements in preterm infants at term age and developmental delay at 3 years of age.

Method

We analysed video recordings of the spontaneous movements in the supine position of 124 preterm infants (44 males, 80 females) at 36 to 44 weeks postmenstrual age (PMA). The infants were born preterm (22–36wks PMA; birthweight 489–1696g) and had not received a diagnosis of a neurological or developmental disorder by the age of 3 years. The recorded spontaneous movements were quantified using six movement indices, which were calculated from two-dimensional trajectories of all limbs. The infants were divided into three developmental groups, normal, borderline, or delayed, based on their developmental quotient as calculated using the Kyoto Scale of Psychological Development 2001 (Kyoto Scale) at 3 years of age. Group differences in the movement indices were analysed.

Results

In the delayed group, average velocity of arms and legs were significantly lower (p<0.05 and p<0.01 respectively), the numbers of movement units of arms and legs were significantly lower (p<0.05 and p<0.01 respectively), kurtosis of acceleration of arms and legs was significantly higher (p<0.05 in each case), and correlation between limb velocities was higher (p<0.05) than in the normal group.

Interpretation

In children who exhibited developmental delay at 3 years of age, the spontaneous movements at term age can be described as less active with intermittent occurrences of abrupt and synchronized movements of the limbs. Recognition of these characteristics of spontaneous movements at term age may be used as a predictor for subsequent cognitive and behavioural development in preterm infants.

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