Sensitivity and specificity of general movements assessment for detecting cerebral palsy in an Australian context:...

We previously reported sensitivity and specificity levels of the general movements assessment (GMA) to detect cerebral palsy (CP) at 1 year within a clinical setting and with the assistance of the New South Wales (NSW) Rater Network. The aim of this study was to determine whether similarly high levels of validity could be maintained in the same group at 2 years.

A prospective longitudinal cross-sectional study was conducted. GMA was blind-rated from conventional video by two independent certified raters, blinded to medical history. A third rater resolved disagreements. High-risk population screening for CP using the GMA during the fidgety period (12-20 weeks) was carried out in four neonatal intensive care units and one CP service over a 30-month period. Participants were 259 high-risk infants for the initial study. Multidisciplinary follow-up at 2-3 years included Bayley Scales of Infant Development and confirmed diagnosis of CP. Sensitivity and specificity values were calculated with true positives defined as a confirmed diagnosis of CP.

At 2-3 years, 184 (71%) completed the follow-up assessment. GMA was normal for 134 (73%, low risk for CP), absent fidgety for 48 (26%, high risk for CP) and abnormal fidgety for 2 (1%, high risk for abnormal neurological disorder). Sensitivity for detecting CP was 97.6% (40/41) and specificity 95.7% (133/139). Sensitivity for detecting any abnormal outcome with absent/abnormal fidgety general movements (GMs) was 57.9% (44/76) and specificity 94.4% (101/107).

Excellent levels of sensitivity and specificity of the GMA for detecting CP in the clinical setting were maintained at 2 years and were similar to our previously reported findings.