Neurologic ExaminationNervous System DiseasesDevelopmental DisabilitiesPsychomotor DisordersMotor Skills DisordersMagnetic Resonance ImagingCerebral PalsyInfant, NewbornBrainChild DevelopmentInfant, PrematureFollow-Up StudiesTomography, X-Ray ComputedProspective StudiesSeverity of Illness IndexRetrospective StudiesTreatment OutcomeRisk FactorsPhysical ExaminationBrain DiseasesCerebellar AtaxiaVitamin E DeficiencyAbetalipoproteinemiaAtaxiaXanthomatosis, CerebrotendinousRefsum DiseaseCerebellar Diseases