Background: Cerebral arteriovenous malformations (AVMs) are congenital masses of arteries and veins that appear to undergo an unclear 'maturation' for many years. Using structured interviews, we compared developmental history of adult patients with AVM with a comparison group of patients with cerebral tumor or aneurysm. Objective: To determine whether a remote history of developmental abnormality in adult patients with AVM might be an early marker of cerebral status. Design: Adult patients with AVM and a comparison group of patients with cerebral aneurysm or low-grade tumor participated in a survey. Setting: Urban medical school-based tertiary care center. Patients: Forty-four randomly selected patients with AVM from the Columbia-Presbyterian AVM Database. There were 32 comparison patients: 15 randomly chosen patients from the institution's Cerebral Aneurysm Database and all 17 patients who underwent a biopsy from 1990 to 1995 with a diagnosis of low-grade tumor and who could be contacted. Main Outcome Measures: A brief, structured interview adapted from the Centers for Disease Control and Prevention for its 1994 study of the prevalence of learning disabilities in American children. We defined the positive occurrence of a condition as an affirmative answer to the question, 'Did have (condition) during his/her school-age years?' Each patient was also asked if there had been any problems in the following skill areas: reading, writing, listening, speaking, attention, impulsivity, organization, mathematics, or drawing. The AVM size was calculated on the angiographic film by measuring its longest diameter in any dimension. Results: Patients with AVM were significantly more likely to report a positive occurrence to any survey question (P<.05). Two thirds of all patients with AVM (66%) reported at least 1 skill difficulty during their school years, significantly more than the comparison group (P<.001). Neither the maximum AVM diameter nor the occurrence of hemorrhage as an adult differed between patients with AVM with and without early skill difficulty. Conclusions: Patients with AVM are more likely to report a developmental learning disorder than patients with tumor or aneurysm despite the absence of other neurologic symptoms of diseases not diagnosed for another 20 years. These data support the notion that disorders of behavioral and intellectual function are sensitive markers of early cerebral status.