Changes in neuropsychological test performance in Veterans with presumed normal pressure hydrocephalus following extended lumbar drain trial.
Normal pressure hydrocephalus (NPH) is a condition of excess cerebrospinal fluid (CSF) accumulation resulting in gait disturbance, urinary incontinence, and cognitive impairment. Although temporary CSF diversion techniques (e.g., lumbar drain; LD) are effective in improving gait, inconsistent findings have been noted for neurocognitive functioning. Findings likely reflect methodological differences (battery length, follow-up duration, practice effects), several of which are addressed in this study. We examined neuropsychological functioning in a group of Veterans with suspected NPH (n=24), pre- and post-lumbar drain. Patients were administered a battery of sensitive neuropsychological measures before and after the LD trial, utilizing alternate forms to mitigate practice effects. Significant improvement (p<0.05) was observed post-LD for phonemic fluency and bilateral finger-tapping speed. Trend-level improvement (p=0.063) was observed on an executive set-shifting measure. Measures of attention, working memory , processing speed, or verbal learning/memory revealed no differences. Temporary CSF diversion appears to have a more pronounced effect on speeded operations (e.g., verbal fluency, finger-tapping) compared to other cognitive domains. Results suggest subtle cognitive changes may be identifiable when using the LD procedure to simulate more permanent CSF diversion (i.e., ventriculoperitoneal shunt).