Neuropsychological Assessment in the Differential Diagnosis of Idiopathic Normal Pressure Hydrocephalus. An Important Tool for the Maintenance and Restoration of Neuronal and Neuropsychological Functions.

Idiopathic normal pressure hydrocephalus (iNPH) is a progressive clinical syndrome that includes gait disturbances, urinary incontinence, and cognitive impairment. iNPH shows similarities to other neurodegenerative disorders, primarily Alzheimer's Disease (AD). Definition of the neuropsychological profile of iNPH and the qualitative analysis of systematic mistakes made in cognitive tests could represent a valid method for systematizing possible specific markers of iNPH dementia and differentiating it from other dementias. To evaluate the role and the efficacy of a neuropsychological protocol, designed at our institution, based on psychometric analysis and qualitative assessment, in the differential diagnosis of iNPH from AD dementia, we prospectively enrolled 12 patients with suspected iNPH, 11 patients with AD, and 10 healthy controls (HC) who underwent neuropsychological assessment. The assessment was done with the Mini Mental State Examination (MMSE), Mental Deterioration Battery (MDB), Frontal Assessment Battery (FAB), and the Deux Barrage Test. Evaluation in the iNPH group was performed before extended lumbar drainage (ELD), 48 h after ELD, and 1 week and 3 months after the insertion of a ventriculoperitoneal shunt (VPS). Statistical analysis demonstrated the cognitive profile of iNPH, which was mainly characterized by executive function and immediate verbal memory impairment compared with AD. Additionally, the neuropsychological markers were different between the two groups. The qualitative analysis of systematic mistakes made on the tests demonstrated differences in cognitive performances between the iNPH, AD, and HC cohorts. Neuropsychological assessment and qualitative evaluation could represent a useful tool for achieving effective management and restoration of functions in patients with iNPH.