<s>[INST] My son aged 11yrs is a premature kid with delayed milestone,now he is taking physiotherapy for his legs,he ismuch good with his IQ. As he had a severe headache and vomitting our doctor suggested to take mri where the finding says PERIVENTRICULAR LEUKOMALACIA.PLS EXPLAIN [/INST] Hi there, Thanks for using Chat Doctor. A fluid called cerebrospinal fluid circulates inside the brain and spinal cord. In the brain it flows through spaces called ventricles. There are four ventricles in the brain there types of tissues white matter and gray matter. In leukoplakia, the white matter is damaged. In periventricular leukoplakia, the white matter around the lateral ventricles is damaged. This injury is more common in preterm babies. This may affect development or can cause symptoms like vision defect and seizures. Is this answer helpful? </s>