Syndrome of normal pressure hydrocephalus: possible relation to hypertensive and arteriosclerotic vasculopathy

Vascular risk factors for idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis

Objective

Idiopathic normal-pressure hydrocephalus (iNPH) is a treatable cause of dementia; however, its etiology and pathogenesis remain poorly understood. The objective of this study was to investigate the prevalence and impact of vascular risk factors in patients with iNPH compared to a control cohort to better understand the potential mechanisms and preventive measures.

Methods

We systematically searched PubMed, Web of Science, Embase, and the Cochrane Library (from inception to December 20, 2022) for studies reporting vascular risk factors for the development of iNPH. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using random-effects models.

Results

After screening 1,462 articles, 11 case-control studies comprising 1,048 patients with iNPH and 79,668 cognitively unimpaired controls were included in the meta-analysis. Our data showed that hypertension (N = 991, OR = 2.30, 95% CI 1.64 to 3.23, I2= 64.0%), diabetes mellitus (DM) (N = 985, OR = 3.12, 95% CI 2.29 to 4.27, I2= 44.0%), coronary heart disease (CHD; N = 880, OR = 2.34, 95% CI 1.33 to 4.12, I2= 83.1%), and peripheral vascular disease (N = 172, OR = 2.77, 95% CI 1.50 to 5.13, I2= 0.0%) increased the risk for iNPH, while overweight was a possible factor (N = 225, OR = 2.01, 95% CI 1.34 to 3.04, I2= 0.0%) based on the sensitivity analysis. Smoking and alcohol consumption were not associated with iNPH.

Conclusions

Our study suggested that hypertension, DM, CHD, peripheral vascular disease, and overweight were associated with iNPH. These factors might be involved in the pathophysiological mechanisms promoting iNPH. These findings require further investigation in future studies.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, CRD42022383004.

Association between vascular risk factors and idiopathic normal pressure hydrocephalus: a Mendelian randomization study

BACKGROUND AND OBJECTIVE

Patients with idiopathic normal pressure hydrocephalus (iNPH) have a higher prevalence of hypertension and diabetes. However, the causal effects of these vascular risk factors on iNPH remain unclear. This study aimed to explore the causal relationship between vascular risk factors (VRFs) and iNPH.

METHODS

We conducted the Mendelian randomization (MR) analysis of iNPH. We included nineteen vascular risk factors related to hypertension, diabetes, lipids, obesity, smoking, alcohol consumption, exercise, sleep, and cardiovascular events as exposure factors. We used the inverse-variance weighted method for causal effect estimation and weighted median, maximum likelihood, and MR Egger regression methods for sensitivity analyses.

RESULTS

We found that genetically predicting essential hypertension (OR = 1.608 (1.330-1.944), p = 0.013) and increased sleep duration (OR = 16.395 (5.624-47.799), p = 0.009) were associated with higher odds of iNPH. Type 1 diabetes (OR = 0.869 (0.828-0.913), p = 0.004) was associated with lower odds of iNPH. For the other 16 VRFs, there was no evidence that they were significantly associated with iNPH. Sensitivity analyses showed that essential hypertension and type 1 diabetes were significantly associated with iNPH.

CONCLUSION

In our MR study on VRFs and iNPH, we found essential hypertension to be a causal risk factor for iNPH. This suggests that hypertension may be involved in the pathophysiological mechanism of iNPH.

Motor sequela of adult and pediatric stroke: Imminent losses and ultimate gains

Stroke is the leading cause of neurological disability in the United States and worldwide. Remarkable advances have been made over the past 20 years in acute vascular treatments to reduce infarct size and improve neurological outcome. Substantially less progress has been made in the understanding and clinical approaches to neurological recovery after stroke. This chapter reviews the epidemiology, bedside examination, localization approaches, and classification of stroke, with an emphasis on motor stroke presentations and management, and promising research approaches to enhancing motor aspects of stroke recovery.

Willis Lecture: Biomarkers for Inflammatory White Matter Injury in Binswanger Disease Provide Pathways to Precision Medicine

Binswanger disease is the small vessel form of vascular cognitive impairment and dementia. Deposition of Alzheimer disease proteins can begin in midlife and progress slowly, whereas aging of the vasculature also can begin in midlife, continuing to progress into old age, making mixed dementia the most common type of dementia. Biomarkers facilitate the early diagnosis of dementias. It is possible to diagnose mixed dementia before autopsy with biomarkers for vascular disease derived from diffusor tensor images on magnetic resonance imaging and Alzheimer disease proteins, Aβ (amyloid β), and phosphorylated tau, in cerebrospinal fluid or in brain with positron emission tomography. The presence of vascular disease accelerates cognitive decline. Both misfolded proteins and vascular disease promote inflammation, which can be detected in cerebrospinal fluid by the presence of MMPs (matrix metalloproteinases), angiogenic growth factors, and cytokines. MMPs disrupt the blood-brain barrier and break down myelin, producing Binswanger disease's 2 main pathological features. Advances in detecting biomarkers in plasma will provide early detection of dementia and aided by machine learning and artificial intelligence, will enhance diagnosis and form the basis for early treatments.

Cerebral autoregulation, cerebrospinal fluid outflow resistance, and outcome following cerebrospinal fluid diversion in normal pressure hydrocephalus

OBJECTIVE

Normal pressure hydrocephalus is not simply the result of a disturbance in CSF circulation, but often includes cardiovascular comorbidity and abnormalities within the cerebral mantle. In this study, the authors have examined the relationship between the global autoregulation pressure reactivity index (PRx), the profile of disturbed CSF circulation and pressure-volume compensation, and their possible effects on outcome after surgery.

METHODS

The authors studied a cohort of 131 patients in whom a clinical suspicion of normal pressure hydrocephalus was investigated. Parameters describing CSF compensation and circulation were calculated during the CSF infusion test, and PRx was calculated from CSF pressure and mean arterial blood pressure (MAP) recordings. A simple scale was used to mark the patients’ outcome 6 months after surgery (improvement, temporary improvement, and no improvement).

RESULTS

The PRx was negatively correlated with resistance to CSF outflow (R = -0.18; p = 0.044); patients with normal CSF circulation tended to have worse autoregulation. The correlation for patients who were surgically treated (n = 83) was R = -0.28; p = 0.01, and it was stronger in patients who experienced sustained improvement after surgery (n = 48, R = -0.43; p = 0.002). In patients who did not improve, the correlation was not significantly different from zero (n = 19, R = -0.07; p = 0.97). There was a trend toward higher values for PRx in nonresponders than in responders (0.16 ± 0.04 vs 0.09 ± 0.02, respectively; p = 0.061), associated with higher MAP values (107.2 ± 8.2 in nonresponders vs 89.5 ± 3.5 in responders; p = 0.195). The product of MAP × (1 + PRx), which was proposed as a measure of combined arterial hypertension and deranged autoregulation, showed a significant association with outcome (greater value in nonresponders; p = 0.013).

CONCLUSION

Autoregulation proves to associate with CSF circulation and appears strongest in shunt responders. Outcome following CSF diversion is possibly most favorable when CSF outflow resistance is increased and global cerebral autoregulation is intact, in combination with arterial normotension.

Association between shunt-responsive idiopathic normal pressure hydrocephalus and alcohol

OBJECTIVE Idiopathic normal pressure hydrocephalus (iNPH) is characterized by ventriculomegaly, gait difficulty, incontinence, and dementia. The symptoms can be ameliorated by CSF drainage. The object of this study was to identify factors associated with shunt-responsive iNPH. METHODS The authors reviewed the medical records of 529 patients who underwent shunt placement for iNPH at their institution between July 2001 and March 2015. Variables associated with shunt-responsive iNPH were identified using bivariate and multivariate analyses. Detailed alcohol consumption information was obtained for 328 patients and was used to examine the relationship between alcohol and shunt-responsive iNPH. A computerized patient registry from 2 academic medical centers was queried to determine the prevalence of alcohol abuse among 1665 iNPH patients. RESULTS Bivariate analysis identified associations between shunt-responsive iNPH and gait difficulty (OR 4.59, 95% CI 2.32-9.09; p < 0.0001), dementia (OR 1.79, 95% CI 1.14-2.80; p = 0.01), incontinence (OR 1.77, 95% CI 1.13-2.76; p = 0.01), and alcohol use (OR 1.98, 95% CI 1.23-3.16; p = 0.03). Borderline significance was observed for hyperlipidemia (OR 1.56, 95% CI 0.99-2.45; p = 0.054), a family history of hyperlipidemia (OR 3.09, 95% CI 0.93-10.26, p = 0.054), and diabetes (OR 1.83, 95% CI 0.96-3.51; p = 0.064). Multivariate analysis identified associations with gait difficulty (OR 3.98, 95% CI 1.81-8.77; p = 0.0006) and alcohol (OR 1.94, 95% CI 1.10-3.39; p = 0.04). Increased alcohol intake correlated with greater improvement after CSF drainage. Alcohol abuse was 2.5 times more prevalent among iNPH patients than matched controls. CONCLUSIONS Alcohol consumption is associated with the development of shunt-responsive iNPH.

Cardiovascular risk factors in Chiari malformation and idiopathic intracranial hypertension

OBJECTIVES

Both Chiari malformation type 1 (CMI, i.e., the idiopathic caudal ectopy of cerebellar tonsils into foramen magnum) and idiopathic intracranial hypertension (IIH) are characterized by reduced intracranial compliance (ICC) due to disturbed circulation of cerebrospinal fluid (CSF). An increasing body of evidence links cardiovascular disease to CSF circulation disturbances. The aim of this study was to explore whether the prevalence of cardiovascular risk factors in patients with CMI or IIH is higher than in the general population.

MATERIALS AND METHODS

Among the patients with CMI or IIH treated at our department during the period 2003-2014, we identified those with history of arterial hypertension (AH), myocardial infarction (MI), angina pectoris (AP), or diabetes mellitus (DM). For comparison with a control population, we retrieved information about the prevalence of AH, MI, AP, and DM among participants of the North-Trøndelag Health Study 3 (HUNT3).

RESULTS

Data from 48 CMI and 52 IIH cases were available. Compared to data from the 42,461 individuals participating in the HUNT3, we found increased prevalence of DM in male CMI as well as female IIH cases, and of AH in female IIH cases. Body mass index (BMI) was significantly increased in both female and male IIH cases. Prevalence of MI and AP in the CMI and IIH cohorts was extremely low and therefore not further studied.

CONCLUSIONS

This study provided evidence of an increased prevalence of DM in male CMI as well as female IIH cases and of AH in female IIH cases. Although requiring further exploration, these findings point to AH and DM as potential risk factors in the pathophysiology of CMI and IIH.

MR Imaging of Cerebrospinal Fluid Dynamics in Health and Disease

The CSF flows in the aqueduct and at the foramen magnum were examined in 5 patients with communicating hydrocephalus (HC) and in 10 with benign intracranial hypertension (BIH) as well as in 5 healthy volunteers. As compared to normal individuals, the aqueductal flow in HC was about 10 times larger and the cervical flow was half as large. In BIH the CSF flows were not different from those of normal volunteers. The decreased arterial expansion as reflected in the reduced cervical flow in HC may be due to pathologic changes in the arteries and paravascular spaces. The large aqueductal flow in HC reflects a large brain expansion, causing increased transcerebral mantle pressure gradient and ventricular dilatation. In BIH there is a normal brain expansion (aqueductal flow) and consequently no ventricular dilatation. It is argued that BIH be caused by an obstruction on the venous side, as opposed to the vascular alterations in HC, which are on the arterial side.

The prevalence of cardiovascular disease in non-communicating hydrocephalus

OBJECTIVE

Hydrocephalus (HC) caused by blockade of ventricular cerebrospinal fluid (CSF) pathways is denoted non-communicating HC. One issue not previously addressed is how the prevalence of cardiovascular disease compares between patients with non-communicating HC and the general population.

METHODS

We examined whether the prevalence of cardiovascular disease (arterial hypertension, angina pectoris, cardiac infarction, and diabetes) differed between cases with non-communicating HC and a general control population, represented by participants of the North-Trøndelag Health 3 Survey (The HUNT3 Survey). A second control group consisted of patients with communicating hydrocephalus (idiopathic normal pressure hydrocephalus, iNPH).

RESULTS

The study included 50 cases with non-communicating HC (53.4+10.5years), and two control cohorts: 35,413 participants of the HUNT3 Survey (52.8+9.6years), and 176 iNPH patients (61.2+8.3years). All individuals were aged 35-70 years. Among the non-communicating HC patients, the results showed increased prevalence for arterial hypertension (males), cardiac infarction (females), and diabetes (females), as compared with the HUNT3 control group with significant odds ratio estimates. However, the prevalence of cardiovascular disease did not significantly differ between patients with non-communicating HC or iNPH. In patients with either non-communicating HC or iNPH and elevated pulsatile intracranial pressure (ICP) during overnight monitoring, the prevalence of diabetes was increased.

CONCLUSION

This study showed significantly increased prevalence of cardiovascular disease in non-communicating HC, indicating an association between cardiovascular disease and the development of non-communicating HC. Further, diabetes was associated with abnormal pulsatile ICP in both non-communicating HC and iNPH patients.

Ventriculoperitoneal shunt placement in poor-grade patients with chronic normal pressure hydrocephalus after aneurysmal subarachnoid haemorrhage

OBJECTIVE

The aim of this study was to analyse the shunt placement in patients who had normal pressure hydrocephalus after poor-grade aneurysmal subarachnoid haemorrhage (aSAH).

METHODS

Patients diagnosed with NPH after poor-grade aSAH were divided into a treatment group and control group, based on whether they had received ventriculoperitoneal shunt placement. The treatment group was then divided into an improvement group and non-improvement group according to their recovery. The Glasgow Outcome Scale and Mini Mental Scale Examination were used for 3 month and 1 year follow-up rehabilitation measures.

RESULTS

Of the 46 total patients, significant improvement was observed at the 3 month and 1 year follow-ups (p < 0.01) after shunt implantation in the treatment group compared to the control group. Furthermore, patients who were younger (p = 0.022), had better neurological function (higher Glasgow Coma Score, p < 0.01) and less severe hydrocephalus (lower EI, p < 0.01) appears to be more likely to benefit from the shunt.

CONCLUSIONS

Patients who had NPH due to poor-grade aSAH would benefit from shunt placement when given the correct candidates and timely management of shunt malfunction. Additionally, the curative effect of the shunt should have been regarded as a long-term goal of rehabilitation in these patients.

Increased prevalence of cardiovascular disease in idiopathic normal pressure hydrocephalus patients compared to a population-based cohort from the HUNT3 survey

Background

Idiopathic normal pressure hydrocephalus (iNPH) is one of few types of dementia that can be treated with shunt surgery and cerebrospinal fluid (CSF) diversion. It is frequently present with cerebral vasculopathy; however, how the prevalence of cardiovascular disease compares between iNPH patients and the general population has not yet been established. Therefore, a case–control study was performed to examine whether the prevalence of cardiovascular disease (arterial hypertension, angina pectoris, cardiac infarction, and diabetes) was different in 440 iNPH patients, when compared to 43,387 participants of the Nord-Trøndelag Health 3 Survey (The HUNT3 Survey), which was considered as the general control population.

Findings

In iNPH patients aged 35–70 years, we found increased prevalence for arterial hypertension (males), angina pectoris (females and males), and cardiac infarction (males), as compared with the HUNT3 control group with significant odds ratio estimates. In addition, the prevalence of diabetes was increased in both age groups 35–70 years (males) and 70–90 years (females and males).

Conclusions

The data show significantly increased prevalence of cardiovascular disease iNPH patients, which provide evidence that cardiovascular disease is involved as an exposure in the development of iNPH.

Disproportionate subarachnoid space hydrocephalus-outcome and perivascular space

Objective

We sought to identify the prevalence of MRI features of disproportionately enlarged subarachnoid space hydrocephalus in possible idiopathic normal pressure hydrocephalus (DESH-iNPH) and to describe the clinico-radiological features and outcomes of a community-based investigation (The Vienna Trans-Danube Aging study).

Methods

Of the 697 inhabitants (all 75 years old), 503 completed extensive neurological examinations at baseline and were followed up every 30 months thereafter with MRIs, mini-mental state examination (MMSE), and the Unified Parkinson Disease Rating Scale-Motor Section (UPDRSM). The DESH-iNPH participant data were compared with the data from participants with Evans index ratios >0.3 (ex vacuo hydrocephalus), cerebral small-vessel diseases, and normal MRIs. The widening of perivascular space was also evaluated by MRI in these groups.

Results

Eight participants with DESH-iNPH (1.6%) and 76 with ex vacuo hydrocephalus (16.1%) at baseline were identified. The mean MMSE in DESH-iNPH, ex vacuo hydrocephalus, and normal MRIs was 26.4, 27.9, and 28.3, respectively, and the mean UPDRSM was 9.75, 2.96, and 1.87, respectively. After a 90-month follow-up, the mortality rates for DESH-iNPH, ex vacuo hydrocephalus, and normal MRIs were 25.0%, 21.3%, and 10.9%, respectively. The perivascular-space widening scores were significantly smaller in the DESH-iNPH cases, particularly at the centrum semiovale, compared to cerebral small-vessel disease and ex vacuo hydrocephalus cases.

Interpretation

The prevalence of DESH-iNPH was 1.6% for participants aged 75 years and revealed significantly lower MMSE and higher UPDRSM scores compared to the ex vacuo hydrocephalus and controls. Moreover, it is suggested that perivascular-space narrowing is a morphological and pathophysiological marker of DESH-iNPH.

Counting-backward test for executive function in idiopathic normal pressure hydrocephalus

OBJECTIVES

The aim of this study was to develop and validate a bedside test for executive function in patients with idiopathic normal pressure hydrocephalus (INPH).

MATERIALS AND METHODS

Twenty consecutive patients with INPH and 20 patients with Alzheimer's disease (AD) were enrolled in this study. We developed the counting-backward test for evaluating executive function in patients with INPH. Two indices that are considered to be reflective of the attention deficits and response suppression underlying executive dysfunction in INPH were calculated: the first-error score and the reverse-effect index. Performance on both the counting-backward test and standard neuropsychological tests for executive function was assessed in INPH and AD patients.

RESULTS

The first-error score, reverse-effect index and the scores from the standard neuropsychological tests for executive function were significantly lower for individuals in the INPH group than in the AD group. The two indices for the counting-backward test in the INPH group were strongly correlated with the total scores for Frontal Assessment Battery and Phonemic Verbal Fluency. The first-error score was also significantly correlated with the error rate of the Stroop colour-word test and the score of the go/no-go test. In addition, we found that the first-error score highly distinguished patients with INPH from those with AD using these tests.

CONCLUSION

The counting-backward test is useful for evaluating executive dysfunction in INPH and for differentiating between INPH and AD patients. In particular, the first-error score may reflect deficits in the response suppression related to executive dysfunction in INPH.

Post-mortem findings in 10 patients with presumed normal-pressure hydrocephalus and review of the literature

AIMS

Neuropathological features of idiopathic normal-pressure hydrocephalus (iNPH) are poorly characterized. Brain biopsy during life may help in the differential diagnosis of dementia, but post-mortem validation of biopsy findings is scarce. Here we review and report brain biopsy and post-mortem neuropathological findings in patients with presumed NPH.

METHODS

We evaluated 10 patients initially investigated by intraventricular pressure monitoring and a frontal cortical biopsy for histological and immunohistochemical assessment as a diagnostic procedure for presumed NPH.

RESULTS

Out of the 10 patients, eight were shunted and seven benefited. Until death, six had developed severe and two mild cognitive impairment. One was cognitively unimpaired, and one was mentally retarded. Three subjects displayed amyloid-β (Aβ) aggregates in their frontal cortical biopsy obtained at the initial procedure. One of these patients developed Alzheimer's disease during a follow-up time of nearly 10 years. One patient with cognitive impairment and NPH suffered from corticobasal degeneration. In six patients various vascular lesions were seen at the final neuropathological investigation. Five of them were cognitively impaired, and in four vascular lesions were seen sufficient in extent to be considered as causative regarding their symptoms.

CONCLUSIONS

The frequent finding of vascular pathology in NPH is intriguing, suggesting that vascular alterations might be causative of cognitive impairment in a notable number of patients with NPH and dementia. Brain biopsy can be used to detect Aβ aggregates, but neuropathological characteristics of iNPH as a distinct disease still need to be discovered.

Normal-pressure hydrocephalus: is there a genetic predisposition?

BACKGROUND

Normal-pressure hydrocephalus (NPH) is characterized by gait disturbance, cognitive impairment, with or without urinary incontinence, enlarged ventricles with or without cerebral atrophy and normal cerebrospinal fluid pressure.

METHODS

We report two sisters with NPH who lived together their entire lives and whose natural history might provide insights into genetic and environmental mechanisms underlying this disorder. Both patients were in their early seventies, single, had similar daily habits and hypertension. No other family members had NPH.

RESULTS

They both underwent shunt placement and showed improvement documented by history and neuropsychological assessment. Both showed a delayed deterioration due to vasculopathy. Both patients were homozygous for the apolipoprotein E (ApoE) e3 allele on chromosome 19. No environmental factors that might have influenced the development of NPH were identified.

CONCLUSION

Our report of two sisters with NPH may indicate the presence of genetic predisposition and further studies involving genetics and environmental factors are necessary to elucidate their role in the pathogenesis of NPH.

White matter diffusion is higher in Binswanger disease than in idiopathic normal pressure hydrocephalus

OBJECTIVES

To explore diagnostic differences in periventricular white matter (PWM) and deep white matter (DWM) diffusion patterns in patients diagnosed with Binswanger disease (BD) and in patients diagnosed with probable idiopathic normal pressure hydrocephalus (INPH) using diffusion-weighted imaging (DWI).

MATERIALS AND METHODS

Apparent diffusion coefficient (ADC) values were calculated in the PWM and DWM in patients with INPH (n = 14) and BD (n = 9) and in controls (n = 10) using an spin echo echo planar imaging single-shot diffusion sequence and region of interest (ROI) analysis.

RESULTS

Patients with BD had higher ADC values than patients with INPH in the PWM and DWM in the frontal and occipital regions (P < 0.05) and higher values than controls in the frontal PWM and DWM (P < 0.01). After shunt surgery, ADC values were reduced in the frontal PWM in patients with INPH (P < 0.05).

CONCLUSIONS

Increased diffusion in the PWM and DWM in patients with BD may reflect irreversible breakdown of axonal integrity caused by the subcortical ischaemic vascular disease. By contrast, the normal white matter diffusion in patients with INPH indicates structurally intact axons, compatible with the reversibility of this disorder. DWI may be an important non-invasive diagnostic tool for differentiating between INPH and BD and identifying shunt responders and reversible brain damage in patients with INPH. However, the overlap between patients with INPH and BD in this study restricts the predictive value of the method.

Long-term outcome in 109 adult patients operated on for hydrocephalus

To examine the long-term effects of surgery in adult hydrocephalus we conducted a cross-sectional questionnaire study assessing both the patients' sense of well-being, and changes in gait, living conditions, daily need of sleep and bladder function. One-hundred-and-nine consecutive patients operated for non-communicating hydrocephalus (N-CH) (22) and communicating normal pressure hydrocephalus (NPH), both idiopathic (38) and secondary (49) were included. For survival analyses, three reference groups were selected from the general population and from the Northern Sweden MONICA Project. At long-term follow-up, 29 (27%) patients had died. Sixty-eight patients (62%) returned the questionnaire, while 12 (11%) patients did not reply. The median follow-up time was 4.2 years (range 2.3 - 6.2 years). Fifty-four (79%) of these patients reported that they still felt improved and 60% had persisting observable improvement of gait, living conditions, bladder function and need of sleep. Intention-to-treat analyses revealed that 54 (50%) of the patients still felt better and 37% remained functionally improved. The standardized mortality ratio (observed/expected) was 3.01 (CI: 2.01 - 4.32).

Shunt-responsive parkinsonism and reversible white matter lesions in patients with idiopathic NPH

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) is a potentially treatable dementia and gait disorder with abnormal CSF dynamics.

OBJECTIVE

To investigate and characterize the changes in motor symptoms and CT and MRI features of iNPH before and after a shunt operation using specific evaluation criteria.

METHODS

We studied 17 definitive iNPH patients, diagnosed according to the clinical guidelines of both the Japanese Society of NPH and the International NPH Consultant Group, with ventricular enlargement (Evan's index > 0.3) and narrowed CSF spaces at the high convexity on CT scan and /or MRI. The pre- and post-operative evaluation criteria for the gait and motor disturbances included the Japanese NPH Grading Scale-Revised (JNPHGSR), the Timed "Up and Go" test and the motor sections of the Unified Parkinson Disease Rating Scale. For cognitive impairments, the JNPHGSR, Mini Mental State Examination, Frontal Assessment Battery and Trail Making Test were used. White matter lesions were rated from the CT and/or MRI using a validated visual rating scale.

RESULTS

All patients showed specific CT and MRI findings, consisting of diffusely-dilated Sylvian fissure, as well as narrowed CSF space at the high convexity. Fifteen patients (88%) showed white matter lesions on their CT or MRI images. These signs were ameliorated in all patients after the shunt operation. Evan's index and the mean total scores on the visual scale for white matter lesions also improved significantly. Clinically, the patients had frequent parkinsonism (71%), but relatively few had a history of either small-vessel diseases (29%), hypertension (41%) or diabetes (35%). All patients showed gait disturbances, and these symptoms, including postural instability and body bradykinesia, improved significantly after the operation. Over half also showed signs of cognitive impairment and urinary incontinence, and all such symptoms and signs improved significantly.

CONCLUSION

iNPH often appears as a shunt-responsive type of parkinsonism and reversible white matter lesions among the geriatric population.

Normal pressure hydrocephalus

Doctors find the management of normal pressure hydrocephalus (NPH) difficult because their diagnosis often is uncertain and the treatment with shunt surgery carries a significant risk. With the aim of bringing to the attention of physicians the useful, but largely anecdotal, information available regarding this problem, this article discusses the epidemiology, reasons why the diagnosis is difficult, differential diagnosis, features of the history, examination, neuropsychologic assessment, radiologic evaluation, and special tests that may help clinicians with management.

Idiopathic normal-pressure hydrocephalus: clinical comorbidity correlated with cerebral biopsy findings and outcome of cerebrospinal fluid shunting

OBJECTIVES

To elucidate the importance of clinically diagnosed cerebral comorbidity in idiopathic normal-pressure hydrocephalus (INPH) and its effect on improvement after shunt surgery as well as concordance with parenchymal pathological changes described in frontal cerebral biopsy specimens.

METHODS

In 28 consecutive patients diagnosed with INPH and shunted according to clinical, radiological and cerebrospinal fluid dynamic criteria, concomitant disorders were carefully registered, with special emphasis on cerebrovascular disease (CVD) and possible Alzheimer's disease. During shunt surgery, a frontal cerebral biopsy specimen was obtained and subsequently analysed for pathological changes.

RESULTS

One or several concurrent disorders were present in 89% of the patients, most often CVD (n = 17) and possible Alzheimer's disease (n = 12), of which eight patients presented both, diagnosed according to the criteria of the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association. The shunt success rate was 33%. A clear tendency towards increasing prevalence of CVD or Alzheimer's disease was found in the subgroups with no improvement or clinical deterioration compared with the patients improving after shunt surgery. The presence of CVD tended towards an unfavourable shunt outcome. The pathological parenchymal changes reflected the clinical diagnoses of comorbidity, and were described in about half of the biopsy specimens, with Alzheimer's disease (n = 7) and vascular changes (n = 7) being the most common findings. However, no significant correlation was found with the clinical diagnoses of Alzheimer's disease and CVD. The presence of cerebral comorbidity, whether diagnosed clinically or by brain biopsy, did not preclude clinical improvement after shunt operation.

CONCLUSIONS

A high prevalence of CVD and Alzheimer's disease was found in patients shunted for INPH, which was reflected, although less commonly, by similar neuropathological biopsy findings. No significant correlation was found between the presence of comorbidity and shunt outcome. The findings support the perception of INPH as a multiaetiological clinical entity, possibly overlapping pathophysiologically with CVD and Alzheimer's disease.

Proton magnetic resonance spectroscopy in patients with normal pressure hydrocephalus

The objective of this prospective study was the application of proton magnetic resonance spectroscopy (1HMRS) in patients with normal pressure hydrocephalus (NPH) to determine the metabolite profile in the white matter next to left lateral ventricle and to assess the relationship of this profile with Evan's index. The study included 26 patients with NPH. Diagnosis of NPH was confirmed by clinical symptoms such as gait disturbance, dementia or urinary incontinence and CT study with ventricular enlargement. Ratios of NAA/Cr, Cho/Cr, Lac/Cr and mI/Cr from deep white matter were measured and compared with Evan's index and diameter of the IIIrd ventricle. Patients with hydrocephalus showed decreased ratios of N-acetylaspartate (NAA)/Cr (creatine), and increased ratios of Lac(lactate)/Cr in the white matter near the left frontal horn of the lateral ventricle compared with a well-matched control group. There was no correlation between NAA/Cr, Ch/Cr, Lac/Cr, mI (myo-Inositol)/Cr and Evan's index. A significant correlation was found between Lac/Cr and third ventricle diameter. A positive correlation was noted between Cho/Cr and dementia in patients with NPH. Our preliminary results of 1 H MRS support the idea that NPH is associated with white matter ischemia. Proton MRS is a very useful tool for evaluating major changes in metabolic levels in deep white matter in NPH patients.

Idiopathic normal pressure hydrocephalus may be a “Two Hit” disease: Benign external hydrocephalus in infancy followed by deep white matter ischemia in late adulthood

PURPOSE

To determine if normal pressure hydrocephalus (NPH) could result from decreased resorption of cerebrospinal fluid (CSF) by the arachnoidal villi, leading to benign external hydrocephalus [BEH] in infancy, followed by deep white matter ischemia (DWMI) in late adulthood (the more hydrophilic environment increasing resistance to CSF flow through the extracellular space (ECS) of the brain).

MATERIALS AND METHODS

CSF outflow via the fourth ventricle and the ECS of the brain was mathematically modeled using a parallel electrical circuit analog. The apparent diffusion coefficient (ADC) was measured as a surrogate of the amount of water in the ECS in normals, patients with symptomatic NPH, and patients with dilated ventricles without symptoms of NPH ("pre-NPH").

RESULTS

The electrical circuit model demonstrates increasing ventricular volume with increasing resistance to flow through the ECS of the brain. ADC measurements performed in the centrum semiovale are significantly higher in patients with NPH and "pre-NPH" than in age-matched controls (P<0.05), controlling for the same degree of DWMI indicating increased fluid in the ECS of the brain.

CONCLUSION

The electrical circuit analog and finding of increased periventricular ADC support the theory that NPH is a "two hit" disease.

Increased intracranial volume: a clue to the etiology of idiopathic normal-pressure hydrocephalus?

BACKGROUND AND PURPOSE

The etiology of idiopathic normal-pressure hydrocephalus (NPH) is unknown. The purpose of this study was to examine the hypothesis that NPH begins in infancy as benign external hydrocephalus due to decreased uptake of CSF by the arachnoid villi. Since this occurs before the sutures fuse, a secondary hypothesis is that the intracranial volumes of patients with NPH should be larger than those of healthy individuals.

METHODS

Intracranial volumes of 51 patients with clinically suspected NPH were compared with those of age- and sex-matched control subjects. All patients underwent phase-contrast CSF velocity MR imaging. They had aqueductal CSF stroke volumes of at least 60 microL, which was 50% higher than previously published normal values. Intracranial volumes were measured and compared between groups.

RESULTS

The average intracranial volume for men with NPH (n = 22) was 1682 mL compared with 1565 for male control subjects (n = 55). The NPH volume averaged 118 mL (7.5%) larger than the control volume (P = .003). The average intracranial volume for women with NPH (n = 29) was 1493 mL compared with 1405 mL for female control subjects (n = 55). The NPH volume was 88 mL (6.3%) larger than the control volume (P = .002).

CONCLUSION

Patients with NPH have intracranial volumes significantly larger than normal, suggesting that the initial insult occurs before the sutures fuse at 1 year of age. The patients somehow remain asymptomatic until their later years, when a second insult must occur, leading to symptomatic NPH.

Is the placement of shunts in patients with idiopathic normal pressure hydrocephalus worth the risk? Results of a study based on continuous monitoring of intracranial pressure

Object. Data from many studies have demonstrated that shunt insertion in patients with idiopathic normal-pressure hydrocephalus (NPH) is associated with high morbidity and a lack of significant improvement; however, the use of strict diagnostic and treatment protocols can improve the results of surgery in these patients. The primary aim in this prospective study was to analyze the results of shunt placement in 43 patients with idiopathic NPH. A secondary aim was to determine the relationship between several clinical and neuroimaging factors, and patient outcome after surgery.

Methods. Thirty men and 13 women with a mean age of 71.1 ± 6.9 years participated in this study. All patients underwent clinical, neuropsychological, and radiological assessment before and 6 months after surgery. In all patients continuous monitoring of intracranial pressure was performed using a fiberoptic extradural sensor. In 31 patients cerebrospinal fluid dynamics were also determined. Eighty-six percent of patients showed clinical improvement after shunt insertion, 11.6% showed no change, and 2.3% exhibited some worsening. Gait improved in 81.4% of the patients, sphincter control in 69.8%, and cognitive dysfunction in 39.5%. There was no treatment-related death. Early or late postsurgical complications occurred in six patients (14%), although all of these complications were minor or were satisfactorily resolved. The complete clinical triad, cortical sulci size, and periventricular lucencies were related to outcome, whereas patient age, symptom duration, ventricular dilation, and the degree of presurgical dementia were unrelated to outcome.

Conclusions. Given the correct diagnosis, shunt insertion can produce marked improvement in patients with idiopathic NPH syndrome, causing few deaths and few clinically relevant complications.

Pattern of white matter regional cerebral blood flow and autoregulation in normal pressure hydrocephalus

The mean cerebral blood flow (CBF) has generally been demonstrated to be lower in normal pressure hydrocephalus (NPH) than in normal controls. We investigated the distribution of the regional peri- and paraventricular white matter CBF (WM CBF) in NPH at baseline and during a controlled rise in intracranial pressure (ICP). Twelve patients with idiopathic NPH (mean age 69 years) underwent a CSF infusion study. CBF was measured by H2(15)O PET at baseline and then during the steady-state plateau of raised ICP. The PET images were co-registered and resliced to 3D structural T1-weighted MRIs. Ten healthy normal volunteers served as control subjects for baseline CBF determination only. Profiles of the regional distribution of the baseline WM CBF and of the percentage change in WM CBF as a function of distance from the ventricles were plotted. The global mean baseline CBF in patients (28.4 +/- 5.2 ml/100 ml/min) was lower than in the control subjects (33 +/- 5.4 ml/100 ml/min) (P < 0.005). In patients, the profile of the regional WM CBF at baseline showed an increase with distance from the ventricles (P < 0.0001), with a maximal reduction adjacent to the ventricles and progressive normalization with distance, whereas in controls no relationship was apparent (P = 0.0748). In 10 patients, the rise in ICP during the infusion produced a fall in cerebral perfusion pressure (CPP) and a significant decrease of the global mean CBF from 27.6 +/- 3.1 to 24.5 +/- 2.9 ml/100 ml/min (P < 0.0001). The profile of the percentage changes in regional WM CBF in patients showed a U-shaped relationship with distance from the ventricles (P = 0.0007), with a maximal decrease skewed on the side of the lateral ventricles at around a mean distance of 9 mm. The WM CBF is reduced in NPH, with an abnormal gradient from the lateral ventricles towards the subcortical WM. An excessive decrease in CBF is brought about by reductions in CPP and appears to be maximal in the paraventricular watershed region. These results are discussed in the light of previous hypotheses concerning the aetiology of periventricular CBF reduction in NPH.

Differences in cerebrospinal fluid dynamics do not affect the levels of biochemical markers in ventricular CSF from patients with aqueductal stenosis and idiopathic normal pressure hydrocephalus

To compare levels of biochemical markers in ventricular cerebrospinal fluid (vCSF) between patients with aqueductal stenosis (AS) and idiopathic normal pressure hydrocephalus (INPH) and relate these results to clinical outcome after surgery. Neurofilament light protein, tau protein, sulfatide, vasoactive intestinal peptide (VIP), neuropeptide PYY (NPY) and CSF/serum albumin ratio were measured in vCSF from 18 consecutive AS and 19 consecutive INPH patients. Clinical outcome was evaluated after surgery by standardized indices. The levels of markers were related to clinical outcome. No differences in any of the markers were found between AS and INPH patients. The concentration of sulfatide and albumin ratio correlated inversely with psychometric improvement, whilst VIP and NPY correlated inversely with improvement in alertness. The similar levels of biochemical markers in vCSF from AS and INPH patients indicate similarities in pathophysiology and turnover rate of vCSF despite differences in CSF dynamics. High albumin ratio and sulfatide concentrations in vCSF in hydrocephalus patients have negative implications for surgical outcome and might indicate concomitant cerebrovascular disorder.

Normal pressure hydrocephalus and cerebral blood flow: a PET study of baseline values

Regional cerebral blood flow (CBF) was studied with O(15)-water positron emission tomography and anatomic region-of-interest analysis on co-registered magnetic resonance in patients with idiopathic (n = 12) and secondary (n = 5) normal pressure hydrocephalus (NPH). Mean CBF was compared with values obtained from healthy volunteers (n = 12) and with clinical parameters. Mean CBF was significantly decreased in the cerebrum and cerebellum of patients with NPH. The regional analysis demonstrated that CBF was reduced in the basal ganglia and the thalamus but not in white matter regions. The results suggest that the role of the basal ganglia and thalamus in NPH may be more prominent than currently appreciated. The implications for theories regarding the pathogenesis of NPH are discussed.

Multi-modal MRI in normal pressure hydrocephalus identifies pre-operative haemodynamic and diffusion coefficient changes in normal appearing white matter correlating with surgical outcome

Magnetic resonance techniques were used to investigate haemodynamic abnormalities and their consequences in normal pressure hydrocephalus (NPH) and to assess changes in these parameters following surgery. Eleven patients with NPH were studied pre- and post-operatively using perfusion and diffusion weighted imaging and compared with ten age-matched controls. Pre-operative periventricular relative cerebral blood volume (rCBV) was reduced in patients (0.76+/-0.11) compared with control (1.16+/-0.16, P<0.01). There was no difference between outcome groups and no change in haemodynamic parameters following surgery. The periventricular apparent diffusion coefficient (ADC) was elevated in the poor outcome group (1.67+/-0.3 x 10(-3) mm(2) s(-1)) compared with both controls (1.04+/-0.4 x 10(-3) mm(2) s(-1), P<0.05) and the good outcome group (0.99+/-0.3 x 10(-3) mm(2) s(-1), P<0.05) despite appearing normal on conventional imaging. In white matter hyperintensities (WMH), rCBV was reduced (0.70+/-0.12 vs. 1.00+/-0.10, P<0.01), and the ADC was increased (1.98+/-0.6 vs. 1.04+/-0.4 x 10(-3) mm(2) s(-1), P<0.05) compared with the same anatomical location in controls. As low rCBV and high ADC is characteristic of chronic infarction, the findings in WMH regions suggest they are irreversibly damaged. Normal appearing periventricular tissue rCBV was reduced, implying that significant haemodynamic consequences contribute to symptoms in NPH. The elevated pre-operative ADC of the same region, was correlated with poor outcome, and may, therefore, be useful in selecting patients for surgery.

Vascular parkinsonism: clinical correlates predicting motor improvement after lumbar puncture

Vascular parkinsonism (VP) is a poorly defined entity which has clinical, and perhaps pathological, overlap with other diagnoses. Although classical VP involves lesions of the basal ganglia, the majority of cases actually show diffuse subcortical white matter changes (SCWMC) on imaging. The exact pathologies of these white matter changes are debated and likely heterogeneous, but are generally thought to represent areas of chronic or recurrent partial ischemia. Cerebrospinal fluid (CSF) drainage is the treatment for NPH and has been reported to improve symptoms in some patients with idiopathic NPH and associated SCWMC. To determine whether historical, clinical, or radiographic factors predict improvement in VP patients after CSF drainage, we removed 35-40 ml of CSF via lumbar punctures (LP) from 40 patients and compared responders with nonresponders for a variety of demographics, clinical features, and blindly interpreted magnetic resonance images (MRI). Fifteen patients (37.5%) reported "significant and irrefutable" gait improvement after LP. Twelve (30.0%) reported no effect and 13 (32.5%) reported mild or very transient improvement. Timed gait in a subset of patients improved (P < 0.05) immediately after LP. Clinically, improvement after CSF removal was predicted by any positive response to levodopa (P < 0.001), the lack of vertical gaze palsies (P < 0.05), the lack of a pure freezing gait (P < 0.05), and the lack of hypotensive episodes (P < 0.05). Blinded MRI interpretation did not find features which clearly predicted response. Some patients diagnosed with VP improved after LP. Clinically, these patients tended to resemble idiopathic PD, whereas nonresponders more closely resembled progressive supranuclear palsy (PSP). These results warrant further investigation and also raise the possibility of testing CSF drainage in patients with idiopathic PD complicated by SCWMC.

Normal pressure hydrocephalus and cerebral blood flow: a review

Normal pressure hydrocephalus is a neurological disease which poses both diagnostic and therapeutic problems for the clinician. The measurement and characterisation of cerebral blood flow has been proposed as a tool for resolving such problems as well as elucidating its pathophysiology. We review the results of studies in which this tool has been applied to normal pressure hydrocephalus patients and consider the merits of the techniques that have been utilised. Finally, consideration is given to feasible future studies and the methods that could be employed in the study of cerebral blood flow and metabolism in patients with normal pressure hydrocephalus.

Idiopathic normal-pressure hydrocephalus: evaluation and findings in a multidisciplinary memory clinic

The diagnostic evaluation of patients with possible idiopathic normal-pressure hydrocephalus (INPH) is traditionally performed in the settings of either neurological, neurosurgical or psychiatric departments. The diagnostic procedure and findings in 71 consecutive patients referred with a clinical and radiological suspicion of INPH to our out-patient multidisciplinary memory clinic are evaluated. Primary diagnoses and potential concomitant disorders considered of secondary importance for the symptomatologies were established. Abnormal hydrodynamics, demonstrated by intraventricular pressure monitoring and infusion test were mandatory for the diagnosis of INPH. Mean age was 68 years and mean Mini-Mental State Examination (MMSE) score was 22. DSM IV criteria of dementia were fulfilled in 42%. In half of the referred patients (n=36), the suspicion of INPH was already disproved subsequently to the evaluation programme performed in the outpatient clinic. The main primary diagnosis was cerebrovascular disease (CVD) comprising 27% (n=19) of the referrals, whereas INPH was diagnosed in only 20% (n=14). Shunt improvement rate was 72%. The remaining patients were diagnosed as having one of 26 different conditions. A multiplicity of disorders mimics the INPH syndrome, with CVD being the primary differential diagnosis. Evaluating patients with possible INPH in an outpatient multidisciplinary memory clinic is an effective and rational diagnostic approach.

Normal pressure hydrocephalus: vascular white matter changes on MR images must not exclude patients from shunt surgery

BACKGROUND AND PURPOSE

White matter changes such as periventricular hyperintensity (PVH) and deep white matter hyperintensity (DWMH) are associated with both periventricular edema and ischemic white matter degeneration. Their diagnostic and predictive value in normal pressure hydrocephalus (NPH) is unclear. To identify prognostically important changes, we classified PVH and DWMH at MR imaging in a large series of patients with NPH, before and after ventriculoperitoneal shunt surgery.

METHODS

Axial proton density- and T2-weighted turbo spin-echo sequences and coronal T1-weighted sequences were performed on a 0.5-T imager in 34 patients with NPH, before and 3 months after shunt surgery. PVH at the anterior, central, and posterior thirds of the lateral ventricles was assessed on transaxial images with a semiquantitative five-step scale describing the extension (in mm) and shape of the PVH. DWMH was quantified with a four-step scale. The number of cortical and subcortical lacunar infarctions, the flow void sign, and the width of the third and lateral ventricles were registered. Gait ability, need for sleep, urinary incontinence, living conditions, and psychometric test performance were assessed pre- and postoperatively.

RESULTS

After shunt surgery, 25 patients improved and nine did not. PVH, DWMH, and other MR imaging variables before shunting did not differ between groups, and no MR imaging variable could predict the clinical effect of shunt surgery. Postoperatively, the width of PVH was reduced in the improved patients, and clinical improvement correlated with reduction in PVH. Only the irregular type of PVH located at the frontal horns was reduced postoperatively. The presence of risk factors or MR imaging changes normally associated with cerebrovascular disease had no negative influence on the outcome of shunt surgery.

CONCLUSION

The presence of DWMH or subcortical lacunar infarctions in NPH did not predict a poor outcome from shunt surgery and should not be used as exclusion criteria for shunting. No MR imaging findings could predict outcome of shunt surgery in patients with NPH. Clinical improvement after surgery is associated with reduction in the irregular type of PVH located around the frontal horns.

CSF sulfatide distinguishes between normal pressure hydrocephalus and subcortical arteriosclerotic encephalopathy

OBJECTIVES

To examine the CSF concentrations of molecules reflecting demyelination, neuronal and axonal degeneration, gliosis, monoaminergic neuronal function, and aminergic and peptidergic neurotransmission in a large series of patients with normal pressure hydrocephalus (NPH) or subcortical arteriosclerotic encephalopathy (SAE), to elucidate pathogenic, diagnostic, and prognostic features.

METHODS

CSF concentrations of glycosphingolipid (sulfatide), proteins (neurofilament triplet protein (NFL), glial fibrillary acidic protein (GFAP)), neuropeptides (vasoactive intestinal peptide (VIP), 4-aminobutyric acid (GABA)), and monoamines (homovanillic acid (HVA), 5-hydroxy-indoleacetic acid (5-HIAA), 4-hydroxy-3-methoxyphenylglycol (HMPG)) were analysed in 43 patients with NPH and 19 patients with SAE. The diagnoses of NPH and SAE were based on strict criteria and patients with NPH were subsequently operated on. Twelve clinical variables, psychometric tests measuring perceptual speed, accuracy, learning, and memory and a psychiatric evaluation were performed in all patients and before and after a shunt operation in patients with NPH.

RESULTS

The CSF sulfatide concentration was markedly increased in patients with SAE (mean 766, range 300-3800 nmol/l) compared with patients with NPH (mean 206, range 50-400 nmol/l) (p<0.001). 5-HIAA, GABA, and VIP in CSF were higher in patients with SAE than in patients with NPH. The patients with NPH with cerebrovascular aetiology had higher sulfatide concentrations and a poorer outcome after shunt surgery than patients with NPH with other aetiologies.

CONCLUSIONS

The pathogenesis of the white matter changes in NPH and SAE is different and ischaemic white matter changes can be a part of the NPH state. The markedly increased CSF sulfatide concentrations in patients with SAE indicate ongoing demyelination as an important pathophysiological feature of SAE. The CSF sulfatide concentration distinguished between patients with SAE and those with NPH with a sensitivity of 74% and a specificity of 94%, making it an important diagnostic marker.

Normal pressure hydrocephalus: developments in determining surgical prognosis

Research into normal pressure hydrocephalus has often focused on the clinical dilemma of selecting patients who will benefit from cerebrospinal fluid diversion. Recent developments in imaging and lumbar infusion tests are throwing light on the underlying pathophysiology, providing researchers with new avenues for the development of reliable investigative tools.

Dutch Normal-Pressure Hydrocephalus Study: the role of cerebrovascular disease

OBJECT

This study was conducted to determine the prevalence of cerebrovascular disease and its risk factors among patients with normal-pressure hydrocephalus (NPH) and to assess the influence of these factors on the outcome of shunt placement.

METHODS

A cohort of 101 patients with NPH underwent shunt placement and was followed for 1 year. Gait disturbance and dementia were quantified using an NPH scale and handicap was determined using a modified Rankin scale (mRS). Primary outcome measures consisted of the differences between preoperative and last NPH scale and mRS scores. The presence of risk factors such as hypertension, diabetes mellitus, cardiac disease, peripheral vascular disease, male gender, and advancing age was recorded. Cerebrovascular disease was defined as a history of stroke or a computerized tomography (CT) scan revealing infarcts or moderate-to-severe white matter hypodense lesions. The prevalence of risk factors for cerebrovascular disease was higher in the 45 patients with cerebrovascular disease than the 56 without it. Risk factors did not influence outcome after shunt placement. Intent-to-treat analysis revealed that the mean improvement in the various scales was significantly less for patients with a history of stroke (14 patients), CT scans revealing infarctions (13), or white matter hypodense lesions (32 patients) than for those without cerebrovascular disease. The proportion of patients who responded to shunt placement was also significantly lower among patients with than those without cerebrovascular disease (p=0.02).

CONCLUSIONS

The authors identified a subgroup of patients with NPH and cerebrovascular disease who showed disappointing results after shunt placement. Cerebrovascular disease was an important predictor of poor outcome.

Neurological signs and frontal white matter lesions in vascular parkinsonism. A clinicopathologic study

BACKGROUND AND PURPOSE

The clinical characteristics and the pathological lesions of so-called vascular parkinsonism (VP) are still debatable. The purpose of this study was to define the core signs and symptoms and assess the cerebrovascular lesions in pathologically confirmed VP.

METHODS

In the present study, VP was defined as the presence of parkinsonism and pathological evidence of cerebrovascular lesions but no depigmentation or Lewy bodies at the substantia nigra. We compared the clinical signs and symptoms of 24 VP patients with those of 30 age-matched patients with pathologically confirmed Parkinson's disease. We compared the brain pathology in VP patients with that in 22 age-matched patients with Binswanger's disease (BD) who had no parkinsonism according to clinical records.

RESULTS

VP was characterized clinically by a short-stepped or frozen gait, lead-pipe rigidity, absence of resting tremor, and negative response to levodopa. Half or more of VP patients demonstrated pyramidal tract signs and pseudobulbar palsies. There was no significant difference in the extent of vascular lesions at the basal ganglia between patients with VP and with BD without parkinsonism. The extent of frontal white matter pallor tended to be less broad in VP than in BD without parkinsonism. In VP patients, the number of oligodendrocytes in the frontal white matter was significantly less than that in age-matched normal control subjects and significantly more than in those with BD.

CONCLUSIONS

The core signs and symptoms of autopsy-proved VP differ from those of typical Parkinson's disease, and most VP patients had diffuse cerebral white matter lesions as well as basal ganglia lesions. VP might be related to frontal white matter lesions.

Frontal brain and leptomeningeal biopsy specimens correlated with cerebrospinal fluid outflow resistance and B-wave activity in patients suspected of normal-pressure hydrocephalus

OBJECTIVE

Normal-pressure hydrocephalus (NPH) is a potentially treatable syndrome with abnormal cerebrospinal fluid dynamics. Meningeal fibrosis and/or obliteration of the subarachnoid space has been suggested as the pathoanatomic basis. The purpose of the present study was to investigate whether meningeal fibrosis causes increased resistance to cerebrospinal fluid outflow (R(out)) and/or increased B-wave activity and whether pathological changes in the brain parenchyma after brain compliance, causing increased B-wave activity.

METHODS

The study involved a group of 38 consecutively studied patients with clinical and radiological evidence of idiopathic NPH, for whom a frontal brain biopsy was obtained. For 29 patients, hydrodynamic criteria of NPH were fulfilled and a ventriculoperitoneal shunt was performed.

RESULTS

Meningeal fibrosis was found in 12 of 25 biopsies containing arachnoid tissue, but no correlation with R(out) or B-waves was found. Pathological parenchymal changes, most often Alzheimer's disease (10 cases) or vascular changes (10 cases), were found in 21 biopsies, but no correlation with B-waves or R(out) was found.

CONCLUSION

The results suggest that leptomeningeal fibrosis is not the only pathoanatomic basis of increased R(out) and/or B-wave activity in patients with NPH and that various degenerative changes in the parenchyma may be responsible for the altered cerebrospinal fluid dynamics characteristic of NPH.