Idiopathic normal pressure hydrocephalus: Validation of the DESH score as a prognostic tool for shunt surgery response.

OBJECTIVE: Several radiological markers have been linked to clinical improvement after shunt surgery for idiopathic normal pressure hydrocephalus (iNPH). However, iNPH has no pathognomonic feature, and patients are still diagnosed as probable, possible, or unlikely cases based on clinical symptoms, imaging findings, and invasive supplementary tests. The predictive value of the disproportionately enlarged subarachnoid space hydrocephalus (DESH) score is not yet conclusively determined, but it might offer a more accurate diagnostic method. The aim of the present retrospective cohort study was to validate the predictive power of the DESH score for clinical improvement after shunt surgery in iNPH patients. METHODS: We retrospectively obtained presurgical MRI and/or CT scans from 71 patients with iNPH who underwent ventriculoperitoneal shunt surgery. Radiological images were evaluated for Evans index (EI), corpus callosal angle (CA), tight high convexity (THC), Sylvian fissure dilation, and focal sulci dilation. These markers were aggregated to determine the DESH score. Patient journal entries were used to subjectively determine the extent of improvement in gait function, urinary incontinence, and/or cognition as a measure of shunt surgery response. RESULTS: Multiple logistic regression analysis, controlling for age and sex (α = 0.05), showed that DESH score was significantly correlated (OR 1.77) with subjective shunt-surgery response at a minimum of 1-month follow-up. Patients with higher DESH scores were more likely to have a favorable response to shunt surgery. CONCLUSION: Aggregating radiological markers into the DESH score is useful for predicting shunt responders among iNPH patients and can aid the selection of patients for surgery. These findings provide further support for the DESH score as a diagnostic tool for iNPH.

Predicting post-surgical outcomes in idiopathic normal pressure hydrocephalus using clinically important changes from the cerebrospinal fluid tap test.

OBJECTIVE: Patients diagnosed with idiopathic Normal Pressure Hydrocephalus (iNPH) typically experience symptom improvements after undergoing a cerebrospinal fluid-tap test (CSF-TT), These improvements are recognized as indicative of potential improvements following surgical intervention. As gait disturbance is the most common iNPH symptom, gait improvements are of predominant interest. The purpose of this study was to examine if clinically important changes in gait and balance from CSF-TT predict meaningful changes following surgery. METHOD: The study involved analysis of data collected in a prospective observational study for 34 iNPH patients who underwent a CSF-TT and subsequent surgery. Linear regression, logistic regression and classification trees were used for predictive modelling comparing changes from CSF-TT with post-surgical changes in Tinetti, Timed Up and Go (TUG) and Berg Balance Scale (BBS) outcomes. RESULTS: Predictive models for minimal clinically important differences (MCIDs) from CSF-TT to surgery were significant for Tinetti (odds ratio = 1.42, p = 0.02) and BBS (odds ratio = 1.57, p < 0.01). Four items on Tinetti and two items on BBS were identified with a predictive accuracy of 79% and 76% respectively. BBS has the highest sensitivity (85%) and negative predictive value (77%). TUG had a 100% specificity and 100% positive predictive value. The predictive model using MCIDs for TUG was not significant (odds ratio = 1.13, p = 0.06). CONCLUSION: Clinically important changes from CSF-TT are useful in predicting post-surgical outcomes in iNPH patients. Tinetti and BBS, both have predictive value using MCID scores as cut off values, of which BBS is a stronger outcome measure for prediction.

Prospective evaluation of flow-regulated valves for idiopathic normal pressure hydrocephalus: 1-year results.

OBJECTIVE: Overdrainage and frequent reprogramming are common problems with programmable valves after ventriculoperitoneal shunt surgery for idiopathic normal pressure hydrocephalus (iNPH). Non-adjustable, flow-regulated valves offer a potential solution to these problems, but there is limited data on their efficacy. This study will evaluate neurological improvement and overdrainage rates within one year of treatment with a flow-regulated valve. PATIENTS AND METHODS: This prospective study analyzes 45 iNPH patients (median age: 73 years) treated with a flow-regulated valve. Clinical evaluations were performed at baseline, postoperatively, and at 3, 6, and 12 months after surgery. The primary efficacy endpoint was improvement of at least 5 points on the iNPH grading scale at follow-up. The safety endpoint was radiographic evidence of overdrainage. RESULTS: All patients presented with gait disturbance, 35 (78 %) had cognitive impairment, and 35 (78 %) had urinary incontinence. The median duration of symptoms was 24 months. The total iNPH score improved in 33/41 (81 %) at 3 months, in 29/34 (85 %) at 6 months, and in 22/29 (64 %) at 12 months. Overall, 40/45 (89 %) patients had a significant improvement on the iNPH scale. Secondary worsening of symptoms after initial improvement was observed in 5 (11 %) patients. Overdrainage occurred in one patient (2 %) requiring surgical evacuation. CONCLUSION: Treatment of iNPH patients with flow-regulated valves resulted in a good neurological outcome with minimal rates of overdrainage. These results are encouraging and justify the clinical use of these valve types.

Risk Analysis Index as a preoperative frailty tool for elective ventriculoperitoneal shunt surgery for idiopathic normal pressure hydrocephalus.

OBJECTIVE: Idiopathic normal pressure hydrocephalus (iNPH) predominantly occurs in older patients, and ventriculoperitoneal shunt (VPS) placement is the definitive surgical treatment. VPS surgery carries significant postoperative complication rates, which may tip the risk/benefit balance of this treatment option for frail, or higher-risk, patients. In this study, the authors investigated the use of frailty scoring for preoperative risk stratification for adverse event prediction in iNPH patients who underwent elective VPS placement. METHODS: The Nationwide Readmissions Database (NRD) was queried from 2018 to 2019 for iNPH patients aged ≥ 60 years who underwent VPS surgery. Risk Analysis Index (RAI) and modified 5-item Frailty Index (mFI-5) scores were calculated and RAI cross-tabulation was used to analyze trends in frailty scores by the following binary outcome measures: overall complications, nonhome discharge (NHD), extended length of stay (eLOS) (> 75th percentile), and mortality. Area under the receiver operating characteristic curve analysis was performed to assess the discriminatory accuracy of RAI and mFI-5 for primary outcomes. RESULTS: A total of 9319 iNPH patients underwent VPS surgery, and there were 685 readmissions (7.4%), 593 perioperative complications (6.4%), and 94 deaths (1.0%). Increasing RAI score was significantly associated with increasing rates of postoperative complications: RAI scores 11-15, 5.4% (n = 80); 16-20, 5.6% (n = 291); 21-25, 7.6% (n = 166); and ≥ 26, 11.6% (n = 56). The discriminatory accuracy of RAI was statistically superior (DeLong test, p < 0.05) to mFI-5 for the primary endpoints of mortality, NHD, and eLOS. All RAI C-statistics were > 0.60 for mortality within 30 days (C-statistic = 0.69, 95% CI 0.68-0.70). CONCLUSIONS: In a nationwide database analysis, increasing frailty, as measured by RAI, was associated with NHD, 30-day mortality, unplanned readmission, eLOS, and postoperative complications. Although the RAI outperformed the mFI-5, it is essential to account for the potentially reversible clinical issues related to the underlying disease process, as these factors may inflate frailty scores, assign undue risk, and diminish their utility. This knowledge may enhance provider understanding of the impact of frailty on postoperative outcomes for patients with iNPH, while highlighting the potential constraints associated with frailty assessment tools.

Comparing the Long-Term Cardiovascular Outcomes of Lumbo-Peritoneal, Ventriculo-Peritoneal, or Non-Shunting Treatment after Idiopathic Normal Pressure Hydrocephalus: A Nationwide Retrospective Cohort Study.

Purpose: With advances in medical technology, the average lifespan has increased, leading to a growing significance of idiopathic normal pressure hydrocephalus (iNPH), particularly in the elderly population. Most patients with iNPH have been treated either with ventriculo-peritoneal shunts (VPS) or conservative measures. However, lumbo-peritoneal shunts (LPS) have emerged as an alternative treatment option for iNPH in recent decades, extensive research still lacks comparing outcomes with LPS to those with VPS or non-surgical treatment. The aim of the resent study is to disclose the long-term therapeutic outcomes of LPS, VPS, and non-shunting in patients with iNPH. Methods: We used the National Health Insurance Research Database in Taiwan to assess the long-term outcomes of these treatment options. We enrolled 5,537 iNPH patients who received shunting surgery, of which 5,254 were VPS and 283 were LPS. To compare the difference between each group, matching was conducted by propensity score matching using a 1:1 ratio based on LPS patients. Primary outcomes included death and major adverse cardiovascular events (MACEs) Results: Our findings show that VPS resulted in significantly more MACEs than non-surgical treatment (Odds ratio: 1.83, 95% confidence interval: 1.16-2.90). In addition, both VPS and LPS groups had significantly lower overall mortality rates than non-shunting group. Moreover, LPS had lower overall mortality but similar MACEs rates to VPS. Conclusions: Based on these findings, we propose that the LPS is preferable to the VPS, and surgical treatment should be considered the primary choice over conservative treatment unless contraindications are present.

Freezing of gait in idiopathic normal pressure hydrocephalus.

BACKGROUND: Reports of freezing of gait (FoG) in idiopathic normal pressure hydrocephalus (iNPH) are few and results are variable. This study's objective was to evaluate the frequency of FoG in a large cohort of iNPH patients, identify FoG-associated factors, and assess FoG's responsiveness to shunt surgery. METHODS: Videotaped standardized gait protocols with iNPH patients pre- and post-shunt surgery (n = 139; median age 75 (71-79) years; 48 women) were evaluated for FoG episodes by two observers (Cohens kappa = 0.9, p < 0.001). FoG episodes were categorized. Mini-mental state examination (MMSE) and MRI white matter hyperintensities (WMH) assessment using the Fazekas scale were performed. CSF was analyzed for Beta-amyloid, Tau, and Phospho-tau. Patients with and without FoG were compared. RESULTS: Twenty-two patients (16%) displayed FoG at baseline, decreasing to seven (8%) after CSF shunt surgery (p = 0.039). The symptom was most frequently exhibited during turning (n = 16, 73%). Patients displaying FoG were older (77.5 vs. 74.6 years; p = 0.029), had a slower walking speed (0.59 vs. 0.89 m/s; p < 0.001), a lower Tinetti POMA score (6.8 vs. 10.8; p < 0.001), lower MMSE score (21.3 vs. 24.0; p = 0.031), and longer disease duration (4.2 vs. 2.3 years; p < 0.001) compared to patients not displaying FoG. WMH or CSF biomarkers did not differ between the groups. CONCLUSIONS: FoG is occurring frequently in iNPH patients and may be considered a typical feature of iNPH. FoG in iNPH was associated with higher age, longer disease duration, worse cognitive function, and a more unstable gait. Shunt surgery seems to improve the symptom.

Symptoms and signs did not predict outcome after surgery: a prospective study of 143 patients with idiopathic normal pressure hydrocephalus.

OBJECTIVE: To determine the utility of symptoms, signs, comorbidities and background variables for the prediction of outcome of treatment in iNPH. METHODS: A prospective observational study of consecutively included iNPH patients, who underwent neurological, physiotherapeutic and neuropsychological assessments before and after shunt surgery. The primary outcome measure was the total change on the iNPH scale, and patients were defined as improved postoperatively if they had improved by at least five points on that scale. RESULTS: 143 iNPH patients were included, and 73% of those were improved after surgery. None of the examined symptoms or signs could predict which patients would improve after shunt surgery. A dominant subjective complaint of memory problems at baseline was predictive of non-improvement. The reported comorbidities, duration of symptoms and BMI were the same in improved and non-improved patients. Each of the symptom domains (gait, neuropsychology, balance, and continence) as well as the total iNPH scale score improved significantly (from median 53 to 69, p < 0.001). The proportions of patients with shuffling gait, broad-based gait, paratonic rigidity and retropulsion all decreased significantly. DISCUSSION: This study confirms that the recorded clinical signs, symptoms, and impairments in the adopted clinical tests are characteristic findings in iNPH, based on that most of them improved after shunt surgery. However, our clinical data did not enable predictions of whether patients would respond to shunt surgery, indicating that the phenotype is unrelated to the reversibility of the iNPH state and should mainly support diagnosis. Absence of specific signs should not be used to exclude patients from treatment.

Neuronal pentraxin 2 correlates with neurodegeneration but not cognition in idiopathic normal pressure hydrocephalus (iNPH).

AIM OF THE STUDY: Neuronal pentraxin-2 (NPTX2) is a synaptic protein responsible for modulating plasticity at excitatory synapses. While the role of NPTX2 as a novel synaptic biomarker in cognitive disorders has been elucidated recently, its role in idiopathic normal pressure hydrocephalus (iNPH) is not yet understood. CLINICAL RATIONALE FOR STUDY: To determine if NPTX2 predicts cognition in patients with iNPH, and whether it could serve as a predictive marker for shunt outcomes. MATERIAL AND METHODS: 354 iNPH patients underwent cerebrospinal fluid drainage (CSF) as part of the tap test or extended lumbar drainage. Demographic and clinical measures including age, Evans Index (EI), Montreal Cognitive Assessment (MoCA) score, Functional Activities Questionnaire (FAQ) score, and baseline and post-shunt surgery Timed Up and Go (TUG) test scores were ascertained. CSF NPTX2 concentrations were measured using an ELISA. CSF ß-amyloid 1-40 (Aß1-40), ß-amyloid 1-42 (Aß1-42), and phosphorylated tau-181 (pTau-181) were measured by chemiluminescent assays. Spearman's correlation was used to determine the correlation between CSF NPTX2 concentrations and age, EI, MoCA and FAQ, TUG, Aß1-40/Aß1-42 ratio, and pTau-181 concentrations. Logistic regression was used to determine if CSF NPTX2 values were a predictor of short-term improvement post-CSF drainage or long-term improvement post-shunt surgery. RESULTS: There were 225 males and 129 females with a mean age of 77.7 years (± 7.06). Average CSF NPTX2 level in all iNPH patients was 559.97 pg/mL (± 432.87). CSF NPTX2 level in those selected for shunt surgery was 505.61 pg/mL (± 322.38). NPTX2 showed modest correlations with pTau-181 (r = 0.44, p < 0.001) with a trend for Aß42/Aß40 ratio (r = -0.1, p = 0.053). NPTX2 concentrations did not correlate with age (r = -0.012, p = 0.83) or MoCA score (r = 0.001, p = 0.87), but correlated negatively with FAQ (r = -0.15, p = 0.019). CONCLUSIONS: While CSF NPTX2 values correlate with neurodegeneration, they do not correlate with cognitive or functional measures in iNPH. CSF NPTX2 cannot serve as a predictor of either short-term or long-term improvement after CSF drainage. CLINICAL IMPLICATIONS: These results suggest that synaptic degeneration is not a core feature of iNPH pathophysiology.

Cerebrospinal fluid shunt surgery reduces the risk of developing dementia and Alzheimer's disease in patients with idiopathic normal pressure hydrocephalus: a nationwide population-based propensity-weighted cohort study.

BACKGROUND: Patients with idiopathic normal-pressure hydrocephalus (iNPH) are predisposed to developing dementing disorders. Cerebrospinal fluid (CSF) shunt implantation is a treatment used to improve the motor and cognitive disabilities of these patients; however, its effect on the risk of developing dementing disorders remains unclear. We conducted a population-based propensity-weighted cohort study to investigate whether CSF shunt surgery may reduce the risk of subsequently developing dementia, Alzheimer's disease (AD), and vascular dementia in iNPH patients. METHODS: Patients aged ≥ 60 years who were diagnosed with iNPH (n = 2053) between January 2001 and June 2018 were identified from the Taiwan National Health Insurance Research Database. Various demographic characteristics (age, sex, and monthly income) and clinical data (incidence year, comorbidities, and Charlson comorbidity index) were collected and divided into the shunt surgery group (SSG) and the non-shunt surgery group (NSSG). Stabilized inverse probability of treatment weighting by using the propensity score was performed to achieve a balanced distribution of confounders across the two study groups. The cumulative incidence rate and risk of dementing disorders were estimated during a 16-year follow-up period. RESULTS: After weighting, the data of 375.0 patients in SSG and 1677.4 patients in NSSG were analyzed. Kaplan-Meier curve analysis indicated that the cumulative incidence rate of AD (p = 0.009), but not dementia (p = 0.241) and vascular dementia (p = 0.761), in SSG was significantly lower than that in NSSG over the 16-year follow-up period. Cox proportional hazards regression analysis revealed that SSG had a reduced hazard ratio (HR) for developing AD [HR (95% CI) 0.17 (0.04-0.69)], but not for dementia [HR (95% CI) 0.83 (0.61-1.12)] and vascular dementia [HR (95% CI) 1.18 (0.44-3.16)], compared with NSSG. Further Fine-Gray hazard regression analysis with death as a competing event demonstrated that SSG had a reduced subdistribution HR (sHR) for developing dementia [sHR (95% CI) 0.74 (0.55-0.99)] and AD [sHR (95% CI) 0.15 (0.04-0.61)], but not for vascular dementia [sHR (95% CI) 1.07 (0.40-2.86)]. CONCLUSION: CSF shunt surgery is associated with reduced risks of the subsequent development of dementia and AD in iNPH patients. Our findings may provide valuable information for assessing the benefit-to-risk profile of CSF shunt surgery.

[Neuropathology of Idiopathic Normal Pressure Hydrocephalus: A Study of Three Autopsy Cases and a Literature Review].

We present neuropathological findings in three autopsy brains from patients diagnosed clinically with idiopathic normal pressure hydrocephalus (iNPH) in Japan; still, specific findings of iNPH remain unclear. Comorbid atherosclerosis and hypertensive microvascular diseases, including arterio- and arteriolosclerosis and ischemic changes in the brain parenchyma, are frequently (65%) observed in autopsy brain tissue from patients with iNPH, which has drawn attention to the clinicopathological similarities and differences between iNPH and Binswanger's disease. Additionally, Aß protein deposition and phosphorylated tau-positive neurofibrillary tangles and neuropil threads are observed in cerebral cortical biopsy specimens obtained during intracranial pressure monitoring or shunt surgery among a subset of patients with iNPH. These findings are as frequent as those reported in autopsy data of the age-matched general population. Alterations in aquaporin-4 expression in the cerebral cortex have also been reported, suggestive of a possible association with altered volume or composition of the interstitial fluid in the microenvironment, particularly in the vicinity of capillaries, or glymphatic system dysfunction and consequent altered interstitial fluid drainage. Greater understanding of the normal anatomical structures and pathways involved in cerebrospinal fluid circulation, particularly in absorption and drainage, in the craniospinal region is essential for better clarity regarding iNPH neuropathology.

[Preoperative Predictors of Outcomes of Cerebrospinal Fluid Shunt Surgery in Patients with Idiopathic Normal Pressure Hydrocephalus].

The disproportionately enlarged subarachnoid space hydrocephalus (DESH) findings on cranial images are useful to predict cerebrospinal fluid (CSF) shunt responsiveness to some extent in patients with idiopathic normal-pressure hydrocephalus (iNPH). However, recent studies show that patients with iNPH often have concomitant Alzheimer's or Lewy body disease regardless of DESH findings, which may be associated with poor outcomes of CSF shunt surgery. Moreover, long-term outcomes after CSF shunt surgery in patients with iNPH, which is one of the most important issues to be addressed for effective treatment of iNPH, remain unknown.

[Challenges to Distinguish Idiopathic Normal Pressure Hydrocephalus from Progressive Supranuclear Palsy].

Idiopathic normal pressure hydrocephalus (iNPH) is a clinical condition characterized by symptoms of gait disturbance, cognitive dysfunction, and urinary disturbance. In contrast, progressive supranuclear palsy (PSP) is a progressive neurodegenerative disease characterized by supranuclear gaze palsy, akinetic rigidity, gait disturbance, and dementia. PSP manifests various clinical phenotypes that mimic other diseases and occasionally present iNPH-like presentations. Our previous publication showed that PSP develops iNPH-like magnetic resonance imaging (MRI) features more frequently than other neurodegenerative diseases. It is thus sometimes challenging to distinguish iNPH from PSP. Recently, we showed that patients with PSP, particularly those with iNPH-like MRI findings, often demonstrate amelioration of their gait disturbance following a spinal tap or shunt operation. Moreover, our study revealed that both patients with iNPH and PSP often manifest a placebo effect that can be evaluated by implementing a sham spinal tap. Therefore, although a positive response to a spinal tap has been thought of as a distinct feature of iNPH, it may not be useful in differentiating iNPH and PSP. However, in clinical practice, comparing the response to a spinal tap with that of a sham spinal tap may help accurately specify patients with iNPH or PSP who definitively respond to the shunt operation.

[Movement Disorders and Rehabilitation in Idiopathic Normal Pressure Hydrocephalus].

Movement disorders, particularly gait and balance disturbances can lead to falls and reduced daily activities in patients with idiopathic normal pressure hydrocephalus (iNPH). In this study, we investigate movement disorders from both the pathophysiological and kinematic perspectives in patients with iNPH. Additionally, we discuss essential factors that should be evaluated before and after cerebrospinal fluid tap tests and shunt surgeries and considerations for assessment of fall risk in patients with iNPH. Additionally, we describe the most recent findings on rehabilitation of iNPH patients.

[Surgical Management of Idiopathic Normal Pressure Hydrocephalus].

Cerebrospinal fluid shunting, including ventriculo-abdominal/atrial and lumbar-abdominal shunts, is the only treatment available for idiopathic normal pressure hydrocephalus (iNPH). Hybrid valves that combine a programmable pressure valve and an antisiphon device are being widely used for treatment of iNPH, which has significantly minimized surgical complications, such as shunt revision and subdural hematomas associated with overdrainage. Development of novel technologies that can maintain a more physiological intracranial environment after shunting presents a challenge for future research.

Clinical improvements in temporospatial gait variables after a spinal tap test in individuals with idiopathic normal pressure hydrocephalus.

Idiopathic Normal Pressure Hydrocephalus (iNPH) is a neurological condition that often presents gait disturbance in the early stages of the disease and affects other motor activities. This study investigated changes in temporospatial gait variables after cerebrospinal fluid (CSF) removal using a spinal tap test in individuals with idiopathic normal pressure hydrocephalus (iNPH), and explored if the tap test responders and non-responders could be clinically identified from temporospatial gait variables. Sixty-two individuals with iNPH were recruited from an outpatient clinic, eleven were excluded, leaving a total of 51 who were included in the analysis. Temporospatial gait variables at self-selected speed were recorded at pre- and 24-h post-tap tests which were compared using Paired t-tests, Cohen's d effect size, and percentage change. A previously defined minimal clinical important change (MCIC) for gait speed was used to determine the changes and to classify tap test responders and non-responders. A mixed model ANOVA was used to determine the within-group, between-group, and interaction effects. Comparisons of the data between pre- and post-tap tests showed significant improvements with small to medium effect sizes for left step length, right step time, stride length and time, cadence, and gait speed. Gait speed showed the largest percentage change among temporospatial gait variables. Within-group and interaction effects were found in some variables but no between-group effect was found. Tap test responders showed significant improvements in right step length and time, stride length and time, cadence, and gait speed while non-responders did not. Some individuals with iNPH showed clinically important improvements in temporospatial gait variables after the tap test, particularly in step/stride length and time, cadence, who could be classified by gait speed. However, gait-related balance variables did not change. Therefore, additional treatments should focus on improving such variables.

Intraventricular Shunt Catheter Placement of Adult Normal Pressure Hydrocephalus Using an AxiEMTM Electromagnetic Neuronavigation System: A Single-Center Experience.

AIM: To prove the superiority of the electromagnetic (EM) neuronavigation technique to increase the accuracy of intraventicular shunt catheter placement, and to reduce accompanying complications. MATERIAL AND METHODS: A total of 21 patients with hydrocephalus [age range (years): 53-84] were studied. All of them had undergone thin-slice, navigation-compatible, computed tomography (CT) preoperatively. Shunt surgery was performed under the guidance of EM neuronavigation technology. All patients underwent follow-up CT the next day to evaluate catheter tip placement and were followed up at 1, 3, 6, and 12 months. RESULTS: All catheter tips were placed properly in front of the foramen of Monro in the desired position, except in one case in which the tip migrated to the perimesencephalic cistern and underwent reoperation in the early postoperative period. No complications due to infection and obstruction were observed in the medium- and long-term follow-ups. The complication rate due to the incorrect catheter positioning was 4.76% of the total cases. CONCLUSION: The placement of the ventricular catheter under EM-guided navigation technology reduces the proximal-end failure caused by malpositioning, obstruction, and infection.

[Clinical features and effects of shunt surgery in patients with progressive supranuclear palsy and idiopathic normal pressure hydrocephalus].

This study aimed to retrospectively review the frequency and clinical features of 13 patients with progressive supranuclear palsy (PSP) and idiopathic normal pressure hydrocephalus (iNPH). All patients were found to have PSP-Richardson's syndrome (PSP-RS). Shunt surgery was effective in 5 of 11 patients (45.5%). A comparison of these 5 patients who responded to shunt surgery versus the remaining 6 patients revealed a significant difference in the reduction of frontal lobe blood flow on cerebral perfusion single-photon emission computed tomography (SPECT) (P = 0.018). These results suggest that PSP-RS is common in patients with PSP and iNPH and indicate the usefulness of cerebral perfusion SPECT in estimating the effect of shunt surgery.

Usefulness of third ventricle volumetry in patients with normal pressure hydrocephalus.

OBJECTIVE: To use third ventricle morphometric variables as a tool for the selection of patients with idiopathic normal pressure hydrocephalus (iNPH) who are candidates for ventriculoperitoneal shunts (VPS). MATERIAL AND METHODS: Retrospective study enrolling patients with iNPH. Katzman infusion test was performed and a Rout > 12 mmHg/mL/min was considered a positive result. The transverse diameter and the volume of the third ventricle were measured in the preoperative MRI. Postoperative improvement was assessed with the NPH score. The results were analysed with SPSS software. RESULTS: 52 patients with a mean age of 76 years were analysed. There was no difference in the diameter of the third ventricle among patients with a positive result and those with a negative result in the infusion test (12.28 vs 11.68 mm; p = 0.14). Neither were difference detected in the ventricle volume of both groups (3.6 vs 3.5cc; p = 0.66). Those patients who improved after VPS had a smaller third ventricle compared to those who did not respond after surgery (11.85 mm vs. 12.96 mm; p = 0.009). Diameter and volume of third ventricle present a significant strong correlation (Pearson correlation coefficient = 0.72; p < 0.0001). CONCLUSION: Morphometric variables of third ventricle may be useful in predicting a good response to VPS in patients with idiopathic normal pressure hydrocephalus.