Development of muscle tone impairments in high-risk infants: Associations with cerebral palsy and cystic periventricular leukomalacia

To assess the prevalence and development of muscle tone impairments in infants at high risk of developmental disorders, and their associations with cerebral palsy (CP) and cystic periventricular leukomalacia (cPVL). Longitudinal exploration of muscle tone in 39 infants at high risk of CP (LEARN2MOVE 0–2 project) mostly due to an early lesion of the brain. Muscle tone was assessed ≥4 times between 0 and 21 months corrected age (CA) with the Touwen Infant Neurological Examination. Diagnosis of CP was determined at 21 months CA. Neonatal neuro-imaging was available. Developmental trajectories were calculated using generalized linear mixed effect models. Infants showed atypical muscle tone in three or four body parts in 93% (172/185) of the assessments. The most prevalent muscle tone pattern was hypotonia of neck and trunk with hypertonia of the limbs (28%). From 7 months CA onwards hypertonia of the arms was associated with CP. Asymmetric arm tone during infancy was associated with unilateral CP. At 18–21 months CA ankle hypertonia was associated with CP at 21 months; leg hypertonia in infancy was not associated with CP. Leg hypertonia was associated with cPVL, regardless of age. High-risk infants due to an early lesion of the brain often present with muscle tone impairment. In these infants, hypertonia and asymmetric muscle tone of the arms were from 7 months onwards associated with the diagnosis of CP at 21 months; hypertonia of the legs was not. •High-risk infants have a high prevalence of muscle tone impairments (>90%).•Axial hypotonia with limb hypertonia is most common pattern in high-risk infants.•From 7 months onwards arm hypertonia was associated with CP.•Asymmetrical muscle tone of the arms was associated with unilateral CP.•Hypertonia of the legs was associated with cPVL.