Classical findings of Normal Pressure Hydrocephalus (NPH) include:
Ataxia (typically the initial and most prominent symptom of NPH)
Urinary Incontinence (typically appears late in the illness)
Abnormal accumulation of cerebrospinal fluid (CSF) gradually dilates the lateral ventricles of the brain. The gradual nature of ventriculomegaly allows for the CSF pressure to adapt and remain normal, hence normal pressure hydrocephalus.
CSF accumulation in the lateral ventricles puts pressure on adjacent cortical tissue and results in the triad listed above.
Verrees M, Selman WR. Management of normal pressure hydrocephalus [summary for patients in Am Fam Physician. 2004;70(6):1085-1086]. Am Fam Physician. 2004;70(6):1071-1078.
McGirt MJ, Woodworth G, Coon AL, et al. Diagnosis, treatment, and analysis of long-term outcomes in idiopathic normal-pressure hydrocephalus. Neurosurgery. 2005;57(4):699-705; discussion 699-705.