The CERAD Neuropsychological Battery in Patients with Idiopathic Normal Pressure Hydrocephalus Compared with Normal Population and Patients with Mild Alzheimer's Disease.

BACKGROUND

The usefulness of CERAD Neuropsychological Battery for describing the cognitive impairment in idiopathic normal pressure hydrocephalus (iNPH) is unknown.

OBJECTIVE

To compare the cognitive profile of patients with iNPH to patients with mild Alzheimer's disease (AD) and age-matched cognitively healthy individuals by using the CERAD-NB.

METHODS

We studied CERAD-NB subtest results, including the Mini-Mental State Examination (MMSE), between 199 patients with probable iNPH, 236 patients with mild AD, and 309 people with normal cognition, using age, education, and gender adjusted multivariate linear regression model. In addition, the effects of AD-related brain pathology detected in frontal cortical brain biopsies in iNPH patients' cognitive profiles were examined.

RESULTS

The iNPH patients performed worse than cognitively healthy people in all CERAD-NB subtests. Despite similar performances in the MMSE, AD patients outperformed iNPH patients in Verbal Fluency (p = 0.016) and Clock Drawing (p < 0.001) tests. However, iNPH patients outperformed AD patients in the Boston Naming Test and Word List Recall and Recognition (p < 0.001). AD-related pathology in brain biopsies did not correlate with the CERAD-NB results.

CONCLUSION

At the time of the iNPH diagnosis, cognitive performances differed from cognitively healthy people in all CERAD-NB subtests. When the iNPH and AD patients' results were compared, the iNPH patients performed worse in Verbal Fluency and Clock Drawing tests while the AD group had more pronounced episodic memory dysfunctions. This study demonstrates significant differences in the CERAD-NB subtests between cognitive profiles of iNPH and AD patients. These differences are not captured by the MMSE alone.