Unilateral thalamic lesions in premature infants: risk factors and short-term prognosis

The aim of the study was to assess incidence, risk factors, clinical symptomatology and short-term outcome of unilateral thalamic lesions in preterm infants, as detected by ultrasound. Sixteen preterm infants, born after a gestational age of less than 35 weeks, with a unilateral thalamic lesion, but without additional significant cerebral lesions, were included. Their follow-up data were compared to those of a selected control group consisting of healthy premature infants. In addition, the neonatal clinical data of the patients with a thalamic lesion were compared to data of the healthy control group and of a general control group, consisting of a non-selected year-cohort of preterm infants. During the study period, the incidence of unilateral thalamic lesions was 5.3% among preterm infants. Ultrasound was not able to distinguish between hemorrhagic and ischemic lesions. The infants with a unilateral thalamic lesion had a more complicated respiratory course and were ventilated significantly longer than infants without such a lesion. The infants with a thalamic lesion had disturbances in tone, persisting throughout infancy, while the healthy control group showed only transient disturbances in tone.