Language and motor findings in benign megalencephaly

9 children between the ages of 5 and 12 yr. whose head circumferences were greater than the 98th percentile and showed negative CT scans and histories for disease associated with increased brain size were studied. A battery of language, articulation, intelligence, and motor tests were administered to subjects and in each case to a sibling whose head circumference was normal. Analysis showed few differences in intelligence and language comprehension between the megalencephalic children and their siblings. Significant differences were observed in motor proficiency, with over 50% of the megalencephalic children scoring below the 10th percentile for their age group. Three megalencephalic children displayed articulation errors. All subjects had at least one parent whose head circumference exceeded the 98th percentile. These results suggest a relationship between benign megalencephaly and developmental motor difficulties.