Study Of Neuropsychological And Imaging Characteristics Of Patients With Idiopathic Normal Pressure Hydrocephalus

Part I. Clinical study of neuropsychological characteristics ofpatients with idiopathic normal pressure hydrocephalus[Objective] To explore the characteristics of cognitive dysfunction in patients withidiopathic normal pressure hydrocephalus(iNPH) by a battery of neuropsychological testsand evaluate the role of these tests in diagnosis.[Methods] Eighteen iNPH patients,20mild Alzheimer’s diease(AD) patients and20healthy volunteers underwent assessment of memory, attention, executive function, andvisuospatial ability using various common neuropsychological measures. The diagnosticspecifity and sensitivity of these measures were analyed by receiver operator characteristiccurve.[Results] Compared with the healthy controls, iNPH patients and AD patients hadsignificant loss of overall cognitive status and various cognitive domains(all P<0.05).There was significant differences between iNPH patients and AD patients in FrontalAssessment Battery, Verbal Fluency Test, time of complete Stroop Color Word Test Card A,time of complete Stroop Color Word Test Card B, time of Stroop Interence Effects andBlock Design Test(all P<0.05). However, no significant differences were detected in wordrecall and word recognition subtests of the Alzheimer’s Diease Assessment Scale, DigitSpan Test and Clock Drawing Test. The areas under the receiver operator characteristiccurve for diagnosis of iNPH by time of complete Stroop Color Word Test Card A, time ofcomplete Stroop Color Word Test Card B and time of Stroop Interence Effects were0.874,0.929,0.869, respectively. And the sensitvity and specifity of three indexes were88.9%and75%,88.9%and85%,94.4%and72.5%, respectively.[Conclusins] Patients with iNPH are impaired in various aspects of cognitioninvolving memory, attention, executive function, and visuospatial ability, the mostprominent of which is the executive dysfunction. In addition, Stroop Color Word Test ishighly diagnostically discriminative for iNPH. Part II. Clinical study of imaging characteristics in patients withidiopathic normal pressure hydrocephalus[Objective] To evaluate the role of Evans index, DESH, callosal angle(CA), protonMR spectroscopy(1H-MRS) and phase-contrast MRI(PC-MRI) in diagnosis anddifferentiation of iNPH from other types of dementia(OD).[Methods] Routine MRI scanning were performed in fifteen iNPH patients,15subcortical arteriosclerotic encephalopathy(SAE) patients and15AD patients.Measurement of Evans index on axial images and CA value and DESH on coronalimages. Seven iNPH patients and seven AD patients underwent measurement of metabolicchanges in the left posterior limb of internal capsule using1H-MRS. And seven iNPHpatients and seven OD patients included four AD patients and three SAE patients wereanalysed cerebrospinal fluid dynamics of aqueduct by PC-MRI.[Results] Evans index and DESH of iNPH patients were significantly greater thanthose of SAE patients and AD patients(all P<0.01). And CA value of iNPH patients wassignificantly smaller than those of SAE patients and AD patients(P<0.01). When usingEvans index of0.3, the sensitivity of100%and100%, and the specificity of76.7%and80%were observed for discrimination of iNPH from SAE and AD patients respectively.Similarly, when using manifest with or without DESH, the sensitvity of60%and60%, andthe specificity86.7%and100%were observed for discrimination of iNPH from SAE andAD patients respectively. iNPH patients had significant higher peak systolic velocity, peaksystolic flow, average flow and stroke volume at aqueduct than OD patients(all P<0.01).There are no significant differences about the ratios of NAA/Cr and Cho/Cr in the leftposterior limb of internal capsule between iNPH patients and AD patients.[Conclusins] Evans index>0.3, DESH and sharp CA are three main morphologicalimaging features of iNPH. Evans index is highly sensitive for the diagnosis of iNPH. AndDESH is highly specific for diagnosis. PC-MRI showed hyperdynamic cerebrospinal fluidflow in patients of iNPH with the aqueduct, and was useful in differentiating iNPH fromother types of dementia. It is not considered that1H-MRS has differentiate the diagnosis ofiNPH and AD.