Normal Pressure Hydrocephalus and Large Head Size

OBJECTIVE: To determine if patients with normal pressure hydrocephalus (NPH) have larger head size than normal controls. BACKGROUND: In 1989, Graff-Radford and Godersky noted that 3 of 30 patients diagnosed with NPH had large heads. They hypothesized that the cause of NPH in their patients was arrested congenital hydrocephalus becoming symptomatic later in life. METHODS: Participants included 31 newly diagnosed NPH patients (21 male, 10 female) seen by the same neurologist (N.R.G.-R.) at Mayo Clinic Jacksonville from January 1, 1995 through December 31, 2000, and 459 normal controls (226 male, 233 female) from the Charlotte County Healthy Aging Study. RESULTS: Head size was statistically larger for NPH males (median, 59.0 cm, range, 57.0-63.0 cm) compared with normal males (median, 57.8 cm, range, 53.3-62.8) (p < 0.01). Head size was also larger for NPH females (median, 6.3 cm, range, 53.5-58.0 cm) compared with normal females (median, 54.6 cm, range, 51.4-59.7 cm) (p < 0.02). CONCLUSION: Patients with NPH have larger head circumferences as a group than normal controls. This was found in both males and females. Results suggest that a significant proportion of patients with NPH may have congenital hydrocephalus that becomes symptomatic later in life.