Predictive value of definitely abnormal general movements in the general population.

Aim: Definitely abnormal general movements in populations of high-risk infants predict serious neurodevelopmental impairment. This study aimed to assess predictive values of definitely abnormal general movements at 3 months for serious neurodevelopmental impairment in a representative sample of the general population.
Method: A prospective cohort study of 455 3-month-old infants was performed (241 females, 214 males; mean birthweight 3452g, SD 604g; mean gestational age 39.4wks, SD 1.96; n=32 born preterm). At enrolment, general movement quality was assessed by means of video recording. At 4 years, all participants were reassessed by well-baby health clinicians; if serious neurodevelopmental impairment was identified, clinical records were reviewed. Predictive values of definitely abnormal general movement quality for major neurodevelopmental impairment were calculated.
Results: Five children were diagnosed as having a major neurodevelopmental disorder with serious implications for daily life, including three children with cerebral palsy (CP). Three out of the five had shown definitely abnormal general movements; they had lesions involving the periventricular white matter. Two children did not show definitely abnormal general movements; one had unilateral spastic CP due to a cortical lesion and the other had ataxia due to cerebellar atrophy. The positive predictive value of definitely abnormal general movements for major neurodevelopmental impairment was 18/100, and for CP it was 12/100. Negative predictive values approached 100%.
Interpretation: The good predictive value of general movement assessment in high-risk populations cannot be generalized to the general population.