Lesions of the basal ganglia and thalamus – the most frequent cause of cerebral palsy in term infants

Objectives: Parasagittal cortico-subcortical lesions (PCSL) and lesions of the basal ganglia and thalamus (BThL) are a typical lesion pattern of the term infant following hypoxic-ischaemic encephalopathy (1). In the context of the European Cerebral Palsy Study (a multicentre study with 6 participating European centres) we analysed magnetic resonance (MR) imaging studies of the brain in a systematic way. The MR findings were related to clinical data.

Material and Methods: Structural MRI of the brain was performed in 350 infants at least once after the age of 18 months. The images were reviewed by two independent reviewers and categorised according to the lesion pattern and severity of the lesion. The above mentioned lesions were associated to neurological and perinatal data.

Results: BThL were present in 44 (13%) of the 350 infants. Forty of those had the typical pattern (of varying degree) following hypoxic-ischaemic encephalopathy, and 4 infants showed isolated lesions of the globus pallidus (Kernikterus). Thirty-five (80%) of the infants had been born at term, 9 (20%) had been born preterm (>32 weeks of gestation). PCSL were less frequent and were seen in 20 (5.7% of the 350) infants. Of those, 8 (40%) had been born preterm. BThL were mainly associated with dyskinetic CP (27 infants, 61%), and PSCL were mainly associated with bilateral spastic CP (16 infants, 80%).

Conclusions: Basal ganglia/thalamus lesoins were more frequent than parasagittal cortico-subcortical lesions. BThL in particular were seen in term infants and this lesion pattern was associated with dyskinetic CP. Associations between the perinatal data and imaging findings will be discussed.

Ref.: 1. Krägeloh-Mann I. Imaging of early brain injury and cortical plasticity. Experimental Neurology 190 (2004) S84-S90