Lack of shunt response in suspected idiopathic normal pressure hydrocephalus with Alzheimer disease pathology (original) (raw)

2010, Annals of Neurology

To determine the impact of cortical Alzheimer disease pathology on shunt responsiveness in individuals treated for idiopathic normal pressure hydrocephalus (iNPH), 37 patients clinically diagnosed with iNPH participated in a prospective study in which performance on neurologic, psychometric, and gait measures before and 4 months after shunting was correlated with amyloid β plaques, neuritic plaques, and neurofibrillary tangles observed in cortical biopsies obtained during shunt insertion. No complications resulted from biopsy acquisition. Moderate to severe pathology was associated with worse baseline cognitive performance and diminished postoperative improvement on NPH symptom severity scales, gait measures, and cognitive instruments compared to patients lacking pathology. Although idiopathic normal pressure hydrocephalus (iNPH) is considered a reversible cause of cognitive and motor impairment in older adults, estimates of the response rate to shunting vary widely. 1,2 One potential contributor to shunt unresponsiveness is the presence of comorbid neurologic conditions that are common in aging. The role of Alzheimer disease (AD) in patients with iNPH is debated. Whereas some data suggest that comorbid AD contributes to poorer response to shunting in patients with otherwise typical symptoms of iNPH, other evidence indicates that patients who demonstrate typical features of iNPH benefit equally from shunting regardless of the presence of AD pathology.