Blindsight as the Plausible Explanation for the Black/White Vision in Normal Pressure Hydrocephalus

The cortical color processing system brain consists of several stages extending from V1 to V4, partly directly but mainly through V2 temporal cortex [1]. Normal pressure hydrocephalus is a neurological disease characterized by an expansion of the ventricles of the brain against the background of normal intracranial pressure values and manifested by a specific triad or symptoms including gait disturbance, cognitive disorders and dysuria [2]. In this study, we assessed the biological marker role of color vision directly, related with the compromise of the cortical pathway V1 and/or V4 causing a black/white vision or, in any way, an impair color vision by normal pressure hydrocephalus patients. 28 Calabrian male patients (age range 51-84 years; mean age 73.2 ±1.57 years) showing a mean disease duration of 4.4 ±0.91 years (range 1.0-23 years) were enrolled. 28 Calabrian males controls were matched for sex and age. An Ophthalmologist examined all patients and controls in order to rule out diabetic retinopathy, cataracts, senile maculopathy, or ocular fundus anomalies. Inherited redgreen colorblind subjects were excluded, too. All patients and controls underwent the Nuclear Magnetic Resonance 3 TESLA to confirm their status and the following clinical tests: Ishihara test [3]; Farnsworth D-15 Test [4], The City University Test [5].