Positive and negative cerebral symptoms: the roles of Russell Reynolds and Hughlings Jackson

Background: Normal pressure hydrocephalus (NPH) is considered to be a treatable form of dementia, because cerebrospinal fluid (CSF) shunting can lessen symptoms.However, neuroimaging has failed to predict when shunting will be effective.Objective: To investigate whether 1 H (proton) magnetic resonance (MR) spectroscopy could predict functional outcome in patients after shunting.Methods: Neurological state including Hasegawa's dementia scale, gait, continence, and the modified Rankin scale were evaluated in 21 patients with secondary NPH who underwent ventriculo-peritoneal shunting.Outcomes were measured postoperatively at one and 12 months and were classified as excellent, fair, or poor.MR spectra were obtained from left hemispheric white matter.Results: Significant preoperative differences in N-acetyl aspartate (NAA)/creatine (Cr) and NAA/choline (Cho) were noted between patients with excellent and poor outcome at one month (p = 0.0014 and 0.0036, respectively).Multiple regression analysis linked higher preoperative NAA/Cr ratio, gait score, and modified Rankin scale to better one month outcome.Predictive value, sensitivity, and specificity for excellent outcome following shunting were 95.2%, 100%, and 87.5%.Multiple regression analysis indicated that NAA/Cho had the best predictive value for one year outcome (p = 0.0032); predictive value, sensitivity, and specificity were 89.5%, 90.0%, and 88.9%.Conclusions: MR spectroscopy predicted long term post-shunting outcomes in patients with secondary NPH, and it would be a useful assessment tool before lumbar drainage.