Blink reflex in young children with medullary kink in Chiari malformation.

We studied the blink reflex (especially the late components ipsi- and contralateral to stimulation site, R2 and R2') in 17 patients under 6 years of age; 12 with Chiari malformation, 1 with Dandy-Walker syndrome and 4 with brainstem tumor. We investigated the correlation between the R2 or R2' and neuro-image findings. Out of various features of the brainstem lesion revealed by MRI or CT examinations, the medullary kink characteristic in Chiari malformation was most responsible for abnormality of R2 and R2'. In addition, the fact that the disturbance of R2 and R2' in patients with Chiari malformation was more apparent in younger children than older ones confirms the intrinsic vulnerability of the blink reflex in the younger age groups as noted in normal children.