Genetic and phenotypic characterization of Parkinson's disease at the clinic-wide level

Observational studies in Parkinson's disease (PD) deeply characterize relatively small numbers of participants. The Molecular Integration in Neurological Diagnosis Initiative seeks to characterize molecular and clinical features of every PD patient at the University of Pennsylvania (UPenn). The objectives of this study are to determine the feasibility of genetic characterization in PD and assess clinical features by sex and GBA1/LRRK2 status on a clinic-wide scale. All PD patients with clinical visits at the UPenn PD Center between 9/2018 and 12/2022 were eligible. Blood or saliva were collected, and a clinical questionnaire administered. Genotyping at 14 GBA1 and 8 LRRK2 variants was performed. PD symptoms were compared by sex and gene groups. 2063 patients were approached and 1,689 (82%) were enrolled, with 374 (18%) declining to participate. 608 (36%) females were enrolled, 159 (9%) carried a GBA1 variant, and 44 (3%) carried a LRRK2 variant. Compared with males, females across gene groups more frequently reported dystonia (53% vs 46%, p = 0.01) and anxiety (64% vs 55%, p < 0.01), but less frequently reported cognitive impairment (10% vs 49%, p < 0.01) and vivid dreaming (53% vs 60%, p = 0.01). GBA1 variant carriers more frequently reported anxiety (67% vs 57%, p = 0.04) and depression (62% vs 46%, p < 0.01) than non-carriers; LRRK2 variant carriers did not differ from non-carriers. We report feasibility for near-clinic-wide enrollment and characterization of individuals with PD during clinical visits at a high-volume academic center. Clinical symptoms differ by sex and GBA1, but not LRRK2, status.

Whole Clinic Research Enrollment in Parkinson's Disease: The Molecular Integration in Neurological Diagnosis (MIND) Study

BACKGROUND

Observational studies in Parkinson's disease (PD) have focused on relatively small numbers of research participants who are studied extensively. The Molecular Integration in Neurological Diagnosis Initiative at the University of Pennsylvania aims to characterize molecular and clinical features of PD in every patient in a large academic center.

OBJECTIVE

To determine the feasibility and interest in a global-capture biomarker research protocol. Additionally, to describe the clinical characteristics and GBA and LRRK2 variant carrier status among participants.

METHODS

All patients at UPenn with a clinical diagnosis of PD were eligible. Informed consent included options for access to the medical record, future recontact, and use of biosamples for additional studies. A blood sample and a completed questionnaire were obtained from participants. Targeted genotyping for four GBA and eight LRRK2 variants was performed, with plasma and DNA banked for future research.

RESULTS

Between September 2018 and December 2019, 704 PD patients were approached for enrollment; 652 (92.6%) enrolled, 28 (3.97%) declined, and 24 (3.41%) did not meet eligibility criteria. Median age was 69 (IQR 63_75) years, disease duration was 5.41 (IQR 2.49_9.95) years, and 11.10%of the cohort was non-white. Disease risk-associated variants in GBA were identified in 39 participants (5.98%) and in LRRK2 in 16 participants (2.45%).

CONCLUSIONS

We report the clinical and genetic characteristics of PD patients in an all-comers, global capture protocol from an academic center. Patient interest in participation and yield for identification of GBA and LRRK2 mutation carriers is high, demonstrating feasibility of PD clinic-wide molecular characterization.

ADNC-RS, a clinical-genetic risk score, predicts Alzheimer's pathology in autopsy-confirmed Parkinson's disease and Dementia with Lewy bodies

Growing evidence suggests overlap between Alzheimer's disease (AD) and Parkinson's disease (PD) pathophysiology in a subset of patients. Indeed, 50-80% of autopsy cases with a primary clinicopathological diagnosis of Lewy body disease (LBD)-most commonly manifesting during life as PD-have concomitant amyloid-beta and tau pathology, the defining pathologies of AD. Here we evaluated common genetic variants in genome-wide association with AD as predictors of concomitant AD pathology in the brains of people with a primary clinicopathological diagnosis of PD or Dementia with Lewy Bodies (DLB), diseases both characterized by neuronal Lewy bodies. In the first stage of our study, 127 consecutive autopsy-confirmed cases of PD or DLB from a single center were assessed for AD neuropathological change (ADNC), and these same cases were genotyped at 20 single nucleotide polymorphisms (SNPs) found by genome-wide association study to associate with risk for AD. In these 127 training set individuals, we developed a logistic regression model predicting the presence of ADNC, using backward stepwise regression for model selection and tenfold cross-validation to estimate performance. The best-fit model generated a risk score for ADNC (ADNC-RS) based on age at disease onset and genotype at three SNPs (APOE, BIN1, and SORL1 loci), with an area under the receiver operating curve (AUC) of 0.751 in our training set. In the replication stage of our study, we assessed model performance in a separate test set of the next 81 individuals genotyped in our center. In the test set, the AUC was 0.781, and individuals with ADNC-RS in the top quintile had four-fold increased likelihood of having AD pathology at autopsy compared with those in each of the lowest two quintiles. Finally, in the validation stage of our study, we applied our ADNC-RS model to 70 LBD individuals from 20 Alzheimer's Disease Research Centers (ADRC) whose autopsy and genetic data were available in the National Alzheimer's Coordinating Center (NACC) database. In this validation set, the AUC was 0.754. Thus, in patients with autopsy-confirmed PD or DLB, a simple model incorporating three AD-risk SNPs and age at disease onset substantially enriches for concomitant AD pathology at autopsy, with implications for identifying LBD patients in which targeting amyloid-beta or tau is a therapeutic strategy.

Pathological Influences on Clinical Heterogeneity in Lewy Body Diseases

PD, PD with dementia, and dementia with Lewy bodies are clinical syndromes characterized by the neuropathological accumulation of alpha-synuclein in the CNS that represent a clinicopathological spectrum known as Lewy body disorders. These clinical entities have marked heterogeneity of motor and nonmotor symptoms with highly variable disease progression. The biological basis for this clinical heterogeneity remains poorly understood. Previous attempts to subtype patients within the spectrum of Lewy body disorders have centered on clinical features, but converging evidence from studies of neuropathology and ante mortem biomarkers, including CSF, neuroimaging, and genetic studies, suggest that Alzheimer's disease beta-amyloid and tau copathology strongly influence clinical heterogeneity and prognosis in Lewy body disorders. Here, we review previous clinical biomarker and autopsy studies of Lewy body disorders and propose that Alzheimer's disease copathology is one of several likely pathological contributors to clinical heterogeneity of Lewy body disorders, and that such pathology can be assessed in vivo. Future work integrating harmonized assessments and genetics in PD, PD with dementia, and dementia with Lewy bodies patients followed to autopsy will be critical to further refine the classification of Lewy body disorders into biologically distinct endophenotypes. This approach will help facilitate clinical trial design for both symptomatic and disease-modifying therapies to target more homogenous subsets of Lewy body disorders patients with similar prognosis and underlying biology. © 2019 International Parkinson and Movement Disorder Society.

The Many Faces of Parkinson's Disease

The total cost of Parkinson disease (PD), which affects nearly 1 million people in the US is $52 billion every year, with $25.4 billion attributable to direct medical costs such as hospitalizations and medication, and $26.5 billion in non-medical costs like missed work, lost wages, early forced retirement, and family caregiver time. The more we know about PD's non-motor symptoms-depression, dementia, fatigue, and others-the better we can treat, and perhaps find a cure, for this neurological disorder.

Progression of alpha-synuclein pathology in multiple system atrophy of the cerebellar type

AIMS

The aim of this study was to identify early foci of α-synuclein (α-syn pathology) accumulation, subsequent progression and neurodegeneration in multiple system atrophy of the cerebellar type (MSA-C).

METHODS

We analysed 70-μm-thick sections of 10 cases with MSA-C and 24 normal controls.

RESULTS

MSA-C cases with the lowest burden of pathology showed α-syn glial cytoplasmic inclusions (GCIs) in the cerebellum as well as in medullary and pontine cerebellar projections. Cerebellar pathology was highly selective and severely involved subcortical white matter, whereas deep white matter and granular layer were only mildly affected and the molecular layer was spared. Loss of Purkinje cells increased with disease duration and was associated with neuronal and axonal abnormalities. Neocortex, basal ganglia and spinal cord became consecutively involved with the increasing burden of α-syn pathology, followed by hippocampus, amygdala, and, finally, the visual cortex. GCIs were associated with myelinated axons, and the severity of GCIs correlated with demyelination.

CONCLUSIONS

Our findings indicate that cerebellar subcortical white matter and cerebellar brainstem projections are likely the earliest foci of α-syn pathology in MSA-C, followed by involvement of more widespread regions of the central nervous system and neurodegeneration with disease progression.

The Penn Parkinson's Daily Activities Questionnaire-15: Psychometric properties of a brief assessment of cognitive instrumental activities of daily living in Parkinson's disease

INTRODUCTION

To describe the psychometric properties of the Penn Parkinson's Daily Activities Questionnaire-15 (PDAQ-15), a 15-item measure of cognitive instrumental activities of daily living for Parkinson's disease (PD) patients derived from the original 50-item PDAQ.

METHODS

PDAQ-15 items were chosen by expert consensus. Knowledgeable informants of PD participants (n = 161) completed the PDAQ-15. Knowledgeable informants were defined as an individual having regular contact with the PD participant. PD participants were assigned a diagnosis of normal cognition, mild cognitive impairment, or dementia based on expert consensus.

RESULTS

PDAQ-15 scores correlated strongly with global cognition (Dementia Rating Scale-2, r = 0.71, p < 0.001) and a performance-based functional measure (Direct Assessment of Functional Status, r = 0.83; p < 0.001). PDAQ-15 scores accurately discriminated between non-demented PD participants (normal cognition/mild cognitive impairment) and PD with dementia (ROC curve area = 0.91), participants with and without any cognitive impairment (normal cognition versus mild cognitive impairment/dementia, ROC curve area = 0.85) and between participants with mild cognitive impairment and dementia (ROC curve area = 0.84).

CONCLUSIONS

The PDAQ-15 shows good discriminant validity across cognitive stages, correlates highly with global cognitive performance, and appears suitable to assess daily cognitive functioning in PD.

An Alzheimer's Disease-Derived Biomarker Signature Identifies Parkinson's Disease Patients with Dementia

Biomarkers from multiple modalities have been shown to correlate with cognition in Parkinson's disease (PD) and in Alzheimer's disease (AD). However, the relationships of these markers with each other, and the use of multiple markers in concert to predict an outcome of interest, are areas that are much less explored. Our objectives in this study were (1) to evaluate relationships among 17 biomarkers previously reported to associate with cognition in PD or AD and (2) to test performance of a five-biomarker classifier trained to recognize AD in identifying PD with dementia (PDD). To do this, we evaluated a cross-sectional cohort of PD patients (n = 75) across a spectrum of cognitive abilities. All PD participants had 17 baseline biomarkers from clinical, genetic, biochemical, and imaging modalities measured, and correlations among biomarkers were assessed by Spearman's rho and by hierarchical clustering. We found that internal correlation among all 17 candidate biomarkers was modest, showing a maximum pairwise correlation coefficient of 0.51. However, a five-marker subset panel derived from AD (CSF total tau, CSF phosphorylated tau, CSF amyloid beta 42, APOE genotype, and SPARE-AD imaging score) discriminated cognitively normal PD patients vs. PDD patients with 80% accuracy, when employed in a classifier originally trained to recognize AD. Thus, an AD-derived biomarker signature may identify PDD patients with moderately high accuracy, suggesting mechanisms shared with AD in some PDD patients. Based on five measures readily obtained during life, this AD-derived signature may prove useful in identifying PDD patients most likely to respond to AD-based crossover therapies.

Longitudinal study of normal cognition in Parkinson disease

OBJECTIVE

To report the rates and predictors of progression from normal cognition to either mild cognitive impairment (MCI) or dementia using standardized neuropsychological methods.

METHODS

A prospective cohort of patients diagnosed with Parkinson disease (PD) and baseline normal cognition was assessed for cognitive decline, performance, and function for a minimum of 2 years, and up to 6. A panel of movement disorders experts classified patients as having normal cognition, MCI, or dementia, with 55/68 (80.9%) of eligible patients seen at year 6. Kaplan-Meier curves and Cox proportional hazard models were used to examine cognitive decline and its predictors.

RESULTS

We enrolled 141 patients, who averaged 68.8 years of age, 63% men, who had PD on average for 5 years. The cumulative incidence of cognitive impairment was 8.5% at year 1, increasing to 47.4% by year 6. All incident MCI cases had progressed to dementia by year 5. In a multivariate analysis, predictors of future decline were male sex (p = 0.02), higher Unified Parkinson's Disease Rating Scale motor score (p ≤ 0.001), and worse global cognitive score (p < 0.001).

CONCLUSIONS

Approximately half of patients with PD with normal cognition at baseline develop cognitive impairment within 6 years and all new MCI cases progress to dementia within 5 years. Our results show that the transition from normal cognition to cognitive impairment, including dementia, occurs frequently and quickly. Certain clinical and cognitive variables may be useful in predicting progression to cognitive impairment in PD.

Development and initial testing of the Penn Parkinson's Daily Activities Questionnaire

OBJECTIVE

The aim of this work was to describe the development and psychometric analysis of the Penn Parkinson's Daily Activities Questionnaire. The questionnaire is an item response theory-based tool for rating cognitive instrumental activities of daily living in PD.

METHODS

Candidate items for the Penn Parkinson's Daily Activities Questionnaire were developed through literature review and focus groups of patients and knowledgeable informants. Item selection and calibration of item-response theory parameters were performed using responses from a cohort of PD patients and knowledgeable informants (n = 388). In independent cohorts of PD patients and knowledgeable informants, assessments of test-retest reliability (n = 50), and construct validity (n = 68) of the questionnaire were subsequently performed. Construct validity was assessed by correlating questionnaire scores with measures of motor function, cognition, an existing activities of daily living measure, and directly observed daily function.

RESULTS

Fifty items were retained in the final questionnaire item bank. Items were excluded owing to redundancy, difficult reading level, and when item-response theory parameters could not be calculated. Test-retest reliability was high (intraclass correlation coefficient = 0.97; P < 0.001). The questionnaire correlated strongly with cognition (r = 0.68; P < 0.001) and directly observed daily function (r = 0.87; P < 0.001), but not with motor impairment (r = 0.08; P = 0.53). The questionnaire score accurately discriminated between PD patients with and without dementia (receiver operating characteristic curve = 0.91; 95% confidence interval: 0.85-0.97).

CONCLUSIONS

The Penn Parkinson's Daily Activities Questionnaire shows strong evidence of reliability and validity. Item response theory-based psychometric analysis suggests that this questionnaire can discriminate across a range of daily functions.

Taste function in early stage treated and untreated Parkinson's disease

Since brain stem regions associated with early Parkinson's disease (PD) pathology encroach upon those involved in taste function, the ability to taste may be compromised in PD. However, studies on this point have been contradictory. We administered well-validated whole-mouth and regional taste tests that incorporated multiple concentrations of sucrose, citric acid, caffeine, and sodium chloride to 29 early stage PD patients and 29 age-, sex-, and race-matched controls. Electrogustometry was also performed on the anterior tongue. The PD cohort was tested both on and off dopamine-related medications in counterbalanced test sessions. While whole-mouth taste identification test scores for all stimuli were, on average, nominally lower for the PD patients than for the controls, a trend in the opposite direction was noted for the intensity ratings at the lower stimulus concentrations for all stimuli except caffeine. Moreover, regional testing found that PD subjects tended to rate the stimuli, relative to the controls, as more intense on the anterior tongue and less intense on the posterior tongue. No significant associations were evident between taste test scores and UPDRS scores, L-DOPA medication equivalency values, or [(99m)Tc]TRODAT-1 SPECT imaging of dopamine transporter uptake within the striatum and associated regions. Our findings suggest that suprathreshold measures of taste function are influenced by PD and that this disease differentially influences taste function on anterior (CN VII) and posterior (CN IX) tongue regions. Conceivably PD-related damage to CN IX releases central inhibition on CN VII at the level of the brainstem, resulting in enhanced taste intensity on the anterior tongue.

Conversion between mini-mental state examination, montreal cognitive assessment, and dementia rating scale-2 scores in Parkinson's disease

Cognitive impairment is one of the earliest, most common, and most disabling non-motor symptoms in Parkinson's disease (PD). Thus, routine screening of global cognitive abilities is important for the optimal management of PD patients. Few global cognitive screening instruments have been developed for or validated in PD patients. The Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and Dementia Rating Scale-2 (DRS-2) have been used extensively for cognitive screening in both clinical and research settings. Determining how to convert the scores between instruments would facilitate the longitudinal assessment of cognition in clinical settings and the comparison and synthesis of cognitive data in multicenter and longitudinal cohort studies. The primary aim of this study was to apply a simple and reliable algorithm for the conversion of MoCA to MMSE scores in PD patients. A secondary aim was to apply this algorithm for the conversion of DRS-2 to both MMSE and MoCA scores. The cognitive performance of a convenience sample of 360 patients with idiopathic PD was assessed by at least two of these cognitive screening instruments. We then developed conversion scores between the MMSE, MoCA, and DRS-2 using equipercentile equating and log-linear smoothing. The conversion score tables reported here enable direct and easy comparison of three routinely used cognitive screening assessments in PD patients.

Lower plasma apolipoprotein A1 levels are found in Parkinson's disease and associate with apolipoprotein A1 genotype

The discovery of novel plasma-based biomarkers could lead to new approaches in the treatment of Parkinson's disease (PD). Here, we explore the role of plasma apolipoprotein A1 (ApoA1) as a risk marker for PD and evaluate the influence of APOA1 promoter variation on plasma ApoA1 levels. Plasma ApoA1 and the single-nucleotide polymorphism, rs670, were assayed in a discovery cohort (cohort 1) of 301 PD patients, 80 normal controls (NCs), and 165 subjects with other neurodegenerative diseases, as well as a cohort (cohort 2) of 158 PD patients from a second clinical site. Additionally, rs670 was genotyped in a third cohort of 1,494 PD and 925 NC subjects from both clinical sites. Compared to both normal and disease controls, PD patients have lower plasma ApoA1 (P < 0.001 for both comparisons). Moreover, in PD patients, plasma ApoA1 levels are correlated with genotype at the APOA1 promoter polymorphism, rs670. Specifically, lower plasma ApoA1 levels were found in rs670 major allele (G) homozygotes in both cohort 1 (P = 0.009) and in a replication cohort (cohort 2; n = 158 PD patients; P = 0.024). Finally, evaluating rs670 genotype frequencies in 1,930 PD cases versus 997 NCs, the rs670 GG genotype shows a trend toward association (odds ratio: 1.1; P = 0.10) with PD. Our results are compatible with a model whereby circulating ApoA1 levels may be useful in risk-stratifying subjects for the development of PD, with higher ApoA1 levels suggesting relative protection. Future studies evaluating modulation of ApoA1 as a novel therapeutic strategy in PD are warranted. © 2014 International Parkinson and Movement Disorder Society.

Suprathreshold odor intensity perception in early-stage Parkinson's disease

BACKGROUND

Whether Parkinson's disease (PD) influences suprathreshold changes in perceived odor intensity is unknown. In patients with Alzheimer's disease, patients with schizophrenia, and the elderly, such perception is reportedly normal. If generally true, this could reflect a core element of the olfactory system insulated to some degree from age- and disease-related pathological conditions.

METHODS

Odor intensity ratings for pentyl acetate were obtained from 29 early-stage PD patients when on and off dopamine-related medications (DRMs) and from 29 matched controls.

RESULTS

The ratings were significantly attenuated at the higher odorant concentrations, with the degree of attenuation associated with overall olfactory dysfunction. Ratings were higher on the right than on the left side of the nose of both patients and controls. No associations with DRMs, Unified Parkinson's Disease Rating Scale (UPDRS) scores, or striatal dopamine transporter imaging were found.

CONCLUSIONS

Parkinson's disease (PD) influences suprathreshold estimates of perceived odor intensity, negating the notion that such perception might be spared in this disease. No association with dopaminergic processes was apparent.

Naltrexone for impulse control disorders in Parkinson disease: a placebo-controlled study

OBJECTIVE

Impulse control disorders (ICDs) in Parkinson disease (PD) are common and can be difficult to manage. The objective of this study was to determine the efficacy and tolerability of naltrexone, an opioid antagonist, for the treatment of ICDs in PD.

METHODS

Patients with PD (n = 50) and an ICD were enrolled in an 8-week, randomized (1:1), double-blind, placebo-controlled study of naltrexone 50-100 mg/d (flexible dosing). The primary outcome measure was response based on the Clinical Global Impression-Change score, and the secondary outcome measure was change in symptom severity using the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS) ICD score.

RESULTS

Forty-five patients (90%) completed the study. The Clinical Global Impression-Change response rate difference favoring naltrexone in completers was 19.8% (95% confidence interval [CI] -8.7% to 44.2%). While this difference was not significant (odds ratio=1.6, 95% CI 0.5-5.2, Wald χ2 [df]=0.5 [1], p=0.5), naltrexone treatment led to a significantly greater decrease in QUIP-RS ICD score over time compared with placebo (regression coefficient for interaction term in linear mixed-effects model=-7.37, F[df]=4.3 [1, 49], p=0.04). The estimated changes in QUIP-RS ICD scores from baseline to week 8 were 14.9 points (95% CI 9.9-19.9) for naltrexone and 7.5 points (95% CI 2.5-12.6) for placebo.

CONCLUSIONS

Naltrexone treatment was not efficacious for the treatment of ICDs in PD using a global assessment of response, but findings using a PD-specific ICD rating scale support further evaluation of opioid antagonists for the treatment of ICD symptoms in PD.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that in patients with PD and an ICD, naltrexone does not significantly increase the probability of achieving response. However, the study lacked the precision to exclude an important difference in response rates.

A platform for discovery: The University of Pennsylvania Integrated Neurodegenerative Disease Biobank

Neurodegenerative diseases (NDs) are defined by the accumulation of abnormal protein deposits in the central nervous system (CNS), and only neuropathological examination enables a definitive diagnosis. Brain banks and their associated scientific programs have shaped the actual knowledge of NDs, identifying and characterizing the CNS deposits that define new diseases, formulating staging schemes, and establishing correlations between neuropathological changes and clinical features. However, brain banks have evolved to accommodate the banking of biofluids as well as DNA and RNA samples. Moreover, the value of biobanks is greatly enhanced if they link all the multidimensional clinical and laboratory information of each case, which is accomplished, optimally, using systematic and standardized operating procedures, and in the framework of multidisciplinary teams with the support of a flexible and user-friendly database system that facilitates the sharing of information of all the teams in the network. We describe a biobanking system that is a platform for discovery research at the Center for Neurodegenerative Disease Research at the University of Pennsylvania.

Association between dopaminergic medications and nocturnal sleep in early-stage Parkinson's disease

BACKGROUND

Poor nocturnal sleep is common in Parkinson's disease (PD) and negatively impacts quality of life. There is little data on how dopaminergic drugs influence nocturnal sleep in PD, particularly in relation to medication timing. We examined the association between dopaminergic medications and subjective and objective nocturnal sleep in PD.

METHODS

Individuals with PD were recruited from the outpatient clinic. Demographics and disease information were collected. Patients underwent one-night polysomnography and responded to SCOPA-SLEEP, a self-administered questionnaire which includes a section on nighttime sleep and an overall measure of sleep quality; higher scores indicate worse sleep. Medication intake, including medication timing in relation to bedtime, was obtained and converted to levodopa equivalents.

RESULTS

41 Males and 21 females, median age 63.9 years, participated. Median disease duration was 5 years. After adjusting for age, sex, disease severity, and disease duration, greater total levodopa equivalent intake within 4 h of sleep was associated with higher total SCOPA-nighttime score (p = 0.009) and greater wake time after sleep onset (p = 0.049). Greater dopaminergic medication intake prior to sleep was also associated with less rapid eye movement (REM) sleep as a percent of total sleep time (p = 0.004).

CONCLUSIONS

Higher amounts of dopaminergic medications taken prior to sleep were associated with poor sleep quality and less REM sleep. Although poor nocturnal sleep in PD is likely multi-factorial in etiology, our findings suggest that timing and dose of medications prior to sleep need to be considered in its management.

Questionnaire-based diagnosis of REM sleep behavior disorder in Parkinson's disease

BACKGROUND

Rapid eye movement (REM) sleep behavior disorder (RBD) is present in around 40% of Parkinson's disease (PD) patients. Definitive diagnosis requires a polysomnogram, but that is costly, time intensive, and not practical for large-scale studies. Therefore, we assessed using a questionnaire-based diagnostic approach.

METHODS

The patient-administered RBD questionnaire and bed-partner-administered question 1 of the Mayo questionnaire were prospectively validated.

RESULTS

Seventy-five PD patients (51 male, 68 Hoehn and Yahr stages I and II) participated. Forty-eight had a clinical history of RBD. Sensitivity was 100% (95% CI, 86.3%-100%) when a combination of both questionnaires was compared with the gold standard of polysomnogram-confirmed RBD. Among those who achieved REM sleep (n=65), specificity was highest for the patient questionnaire used alone, at 82.4% (95% CI, 64.8%-92.6%).

CONCLUSIONS

A combination of patient and bed-partner questionnaires is a useful tool to detect RBD.

Phosphorylated α-synuclein in Parkinson's disease

Phosphorylated α-synuclein (PS-129), a protein implicated in the pathogenesis of Parkinson's disease (PD), was identified by mass spectrometry in human cerebrospinal fluid (CSF). A highly sensitive and specific assay was established and used to measure PS-129 together with total α-synuclein in the CSF of patients with PD, other parkinsonian disorders such as multiple system atrophy (MSA) and progressive supranuclear palsy (PSP), and healthy individuals (a total of ~600 samples). PS-129 CSF concentrations correlated weakly with PD severity and, when combined with total α-synuclein concentrations in CSF, contributed to distinguishing PD from MSA and PSP. Further rigorous validation in independent cohorts of patients, especially those where samples have been collected longitudinally, will determine whether the concentration of PS-129 in CSF will be useful for diagnosing PD and for monitoring PD severity and progression.

Building an integrated neurodegenerative disease database at an academic health center

BACKGROUND

It is becoming increasingly important to study common and distinct etiologies, clinical and pathological features, and mechanisms related to neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and frontotemporal lobar degeneration. These comparative studies rely on powerful database tools to quickly generate data sets that match diverse and complementary criteria set by them.

METHODS

In this article, we present a novel integrated neurodegenerative disease (INDD) database, which was developed at the University of Pennsylvania (Penn) with the help of a consortium of Penn investigators. Because the work of these investigators are based on Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and frontotemporal lobar degeneration, it allowed us to achieve the goal of developing an INDD database for these major neurodegenerative disorders. We used the Microsoft SQL server as a platform, with built-in "backwards" functionality to provide Access as a frontend client to interface with the database. We used PHP Hypertext Preprocessor to create the "frontend" web interface and then used a master lookup table to integrate individual neurodegenerative disease databases. We also present methods of data entry, database security, database backups, and database audit trails for this INDD database.

RESULTS

Using the INDD database, we compared the results of a biomarker study with those using an alternative approach by querying individual databases separately.

CONCLUSIONS

We have demonstrated that the Penn INDD database has the ability to query multiple database tables from a single console with high accuracy and reliability. The INDD database provides a powerful tool for generating data sets in comparative studies on several neurodegenerative diseases.

Association between cognition and function in patients with Parkinson disease with and without dementia

Patients with Parkinson's disease (PD) often have cognitive deficits from the time of diagnosis. Except in patients with dementia, the impact of cognitive symptoms on daily function is not well documented. This study had two objectives: (1) to determine the functional significance of cognitive deficits in nondemented patients with PD and (2) to assess the sensitivity of two measures of global cognitive abilities to identify individuals with impaired ADL function. One hundred eleven subjects with PD and a range of cognitive abilities were included. Of these, 20 were diagnosed with PDD. All subjects were assessed with the Mattis Dementia Rating Scale to two (DRS-2) and the Mini-Mental State Examination (MMSE). ADL function was reported by an informant using the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory (ADCS-ADL). The ability of the DRS-2 and MMSE to capture the impact of cognitive impairment on ADL function was assessed in the entire cohort and in subsets of nondemented individuals. After adjustment for covariates, cognition as measured by the DRS-2 was strongly related to ADL function in the entire cohort (partial correlation coefficient = 0.55, P < 0.001). The association remained strong when only nondemented subjects were included (r = 0.42, P < 0.001). The DRS-2 was significantly more accurate than the MMSE, particularly for detecting milder degrees of ADL impairment (ROC area = 0.87 vs. 0.75, P = 0.0008). Cognition is associated with impairment in ADL function, even in nondemented patients with PD. However, sensitive cognitive assessment measures may be needed to identify these functionally relevant impairments.

CSF amyloid {beta} 1-42 predicts cognitive decline in Parkinson disease

OBJECTIVE

Cognitive decline associated with Parkinson disease (PD) is common and highly disabling. Biomarkers that help identify patients at risk for cognitive decline would be useful additions to the clinical management of the disease.

METHODS

A total of 45 patients with PD were enrolled in this prospective cohort study and had at least 1 yearly longitudinal follow-up evaluation. CSF was collected at baseline and cognition was assessed at baseline and follow-up visits using the Mattis Dementia Rating Scale (DRS-2). CSF was tested for amyloid β 1-42 (Aβ(1-42)), p-tau(181p), and total tau levels using the Luminex xMAP platform. Mixed linear models were used to test for associations between baseline CSF biomarker levels and change in cognition over time.

RESULTS

Lower baseline CSF Aβ(1-42) was associated with more rapid cognitive decline. Subjects with CSF Aβ(1-42) levels ≤192 pg/mL declined an average of 5.85 (95% confidence interval 2.11-9.58, p = 0.002) points per year more rapidly on the DRS-2 than subjects above that cutoff, after adjustment for age, disease duration, and baseline cognitive status. CSF total tau and p-tau(181p) levels were not significantly associated with cognitive decline.

CONCLUSIONS

Reduced CSF Aβ(1-42) was an independent predictor of cognitive decline in patients with PD. This observation is consistent with previous research showing that Alzheimer disease pathology contributes to cognitive impairment in PD. This biomarker may provide clinically useful prognostic information, particularly if combined with other risk factors for cognitive impairment in PD.

Design of comprehensive Alzheimer's disease centers to address unmet national needs

The problem of Alzheimer's disease (AD) exemplifies the challenges of dealing with a broad range of aging-related chronic disorders that require long-term, labor-intensive, and expensive care. As the baby boom generation ages and brain diseases become more prevalent, the need to confront the pending health care crisis is more urgent than ever before. Indeed, there is now a critical need to expand significantly the national effort to solve the problem of AD, with special focus on prevention. The Campaign to Prevent Alzheimer's Disease by 2020 (PAD2020) aims to create a new paradigm for planning and supporting the organization of worldwide cooperative research networks to develop new technologies for early detection and treatments of aging-related memory and motor impairments. PAD 2020 is developing an implementation plan to justify (1) increasing the federal budget for research, (2) developing novel national resources to discover new interventions for memory and motor disorders, and (3) creating innovative and streamlined decision-making processes for selecting and supporting new ideas. Since 1978 the National Institute on Aging or National Institute of Health (NIH) established an extensive national network of AD research facilities at academic institutions including AD Centers (ADCs), Consortium to Establish a Registry for AD, AD Cooperative Study (ADCS), AD Drug Discovery Program, National Alzheimer's Coordinating Center, National Cell Repository for AD, and AD Neuroimaging Initiative. However, despite the success of these programs and their critical contributions, they are no longer adequate to meet the challenges presented by AD. PAD 2020 is designed to address these changes by improving the efficiency and effectiveness of these programs. For example, the ADCs (P30s and P50s) can be enhanced by converting some into Comprehensive Alzheimer's Disease Centers (CADCs) to support not only research, but also by being demonstration projects on care/treatment, clinical trials, and education as well as by seamlessly integrating multisite collaborative studies (ADCS, AD Neuroimaging Initiative, Patient Registries, Clinical Data Banks, etc) into a cohesive structure that further enhances the original mission of the National Institute on Aging ADCs. Regional CADCs offer greater efficiency and cost savings while serving as coordinating hubs of existing ADCs, thereby offering greater economies of scale and programmatic integration. The CADCs also broaden the scope of ADC activities to include research on interventions, diagnosis, imaging, prevention trials, and other longitudinal studies that require long-term support. Thus, CADCs can address the urgent need to identify subjects at high risk of AD for prevention trials and very early in the course of AD for clinical trials of disease modification. The enhanced CADCs will allow more flexibility among ADCs by supporting collaborative linkages with other institutions and drawing on a wider expertise from different locations. This perspective article describes the University of Pennsylvania (Penn) CADC Model as an illustrative example of how an existing ADC can be converted into a CADC by better utilization of Penn academic resources to address the wide range of problems concerning AD. The intent of this position paper is to stimulate thinking and foster the development of other or alternative models for a systematic approach to the study of dementia and movement disorders.

Co-morbidity of TDP-43 proteinopathy in Lewy body related diseases

Here, we investigated if TAR-DNA-binding protein-43 (TDP-43), the disease protein in frontotemporal lobar degeneration and ubiquitin inclusions with or without motor neuron disease as well as amyotrophic lateral sclerosis, also formed inclusions in Lewy body (LB) disorders including Parkinson's disease (PD) without or with dementia (PDD), and dementia with LBs (DLB) alone or in association with Alzheimer's disease (AD). Immunohistochemical analyses of TDP-43 in clinically well characterized and pathologically confirmed cases of DLB + AD, PD and PDD demonstrated TDP-43 pathology in the following percentage of cases: DLB + AD = 25/80 (31.3%); PD = 5/69 (7.2%); PDD = 4/21 (19%), while DLB and normal controls exhibited no (0/10, 0%) and one cases (1/33, 3%) presenting TDP-43 pathology, respectively. Significant differences in the prevalence of TDP-43 lesions were noted between disease versus normal brains (P < 0.001) as well as demented versus non-demented brains (P < 0.001). Statistical analyses revealed a positive relationship between TDP-43 lesions and several clinical and pathological parameters in these disorders suggesting the TDP-43 pathology may have co-morbid effects in LB diseases. This study expands the concept of TDP-43 proteinopathies by implicating TDP-43 lesions in mechanisms of neurodegeneration in LB disorders.

Deep brain stimulation in neurologic disorders

Deep brain stimulation (DBS) is an effective surgical therapy for well-selected patients with medically intractable Parkinson's disease (PD) and essential tremor (ET). The purpose of this review is to describe the success of DBS in these two disorders and its promising application in dystonia, Tourette Syndrome (TS) and epilepsy. In the last 10 years, numerous short- and intermediate-term outcome studies have demonstrated significant relief to patients with PD and ET. A few long-term follow-up studies have also reported sustained benefits. When successful, DBS greatly reduces most of parkinsonian motor symptoms and drug-induced dyskinesia, and it frequently improves patients' ability to perform activities of daily living with less encumbrance from motor fluctuations. Quality of life is enhanced and many patients are able to significantly reduce the amount of antiparkinsonian medications required to still get good pharmacological benefit. Overall, adverse effects associated with DBS tend to be transient, although device-related and other postoperative complications do occur. DBS should be considered the surgical procedure of choice for patients who meet strict criteria with medically intractable PD, ET and selected cases of dystonia.

Unexpected abundance of pathological tau in progressive supranuclear palsy white matter

OBJECTIVE

To investigate whether biochemical insoluble tau with 4 (4R) and/or 3 (3R) microtubule-binding repeats accumulate in white as well as gray matter in progressive supranuclear palsy (PSP), a neurodegenerative tauopathy.

METHODS

To assess tau pathology in PSP white matter, we combined Western blot (WB) and immunohistochemical methods to analyze 23 autopsy-confirmed PSP brains.

RESULTS

WBs showed an unexpected abundance of insoluble tau in white and gray matter of PSP brains, but biochemical tau pathology in white matter was not correlated with immunohistochemistry using the same panel of epitope-specific anti-tau antibodies used for WB. Despite heterogeneity in the representation of pathological 3R and 4R tau isoforms in cortical versus subcortical regions, biochemically detectable white matter tau pathology is a constant feature of PSP.

INTERPRETATION

These studies show additional similarities between PSP and corticobasal degeneration, but unlike corticobasal degeneration, more abundant white matter tau pathology in PSP is detectable by WB than by immunohistochemistry. The differential detection of abnormal tau by biochemistry versus microscopy in PSP may reflect distinct pathological mechanisms, and elucidation of these processes will augment efforts to develop better strategies for the diagnosis and treatment of PSP and related neurodegenerative tauopathies.

Long-term effects of bilateral subthalamic nucleus stimulation on health-related quality of life in advanced Parkinson's disease

We evaluated the long-term effects of subthalamic nucleus (STN) stimulation on health-related quality of life (HRQL) in patients with advanced Parkinson's disease (PD). STN stimulation improves motor function and decreases medication requirements in patients with advanced PD. The impact of STN stimulation on HRQL is less well established, especially beyond 1 year after surgery. We report HRQL outcomes for 18 patients with advanced PD. Patients were evaluated with the Parkinson's Disease Questionnaire-39 (PDQ-39), the Medical Outcome Study Short Form (SF-36), and the EuroQol visual analogue scale (VAS) before surgery, 6 months postoperatively, and at a long-term follow-up visit (mean, 35.9 months; range, 18-57 months after surgery). Preoperative scores on HRQL measures were compared to results obtained at short- and long-term follow-up evaluations. The VAS and all domains of the PDQ-39 except for cognition, communication, and social support showed marked improvements at 6 months after surgery. At the long-term follow-up, there were sustained improvements in the VAS (63% improvement; P = 0.0009) and in several domains of the PDQ-39 [mobility: 20%, P = 0.01; activities of daily living (ADL): 29%, P = 0.005; emotional well-being: 26%, P = 0.02; stigma: 43%, P = 0.003; and bodily discomfort: 35%, P = 0.007]. At the long-term evaluation, only the vitality domain of the SF-36 was significantly improved from baseline (16%; P = 0.01). In this selected group of patients, many of the short-term gains in HRQL persist beyond 18 months after STN implantation. Benefits in nonmotor aspects of HRQL such as bodily discomfort and stigma appear to be among the most durable.

Differences in [99mTc]TRODAT-1 SPECT binding to dopamine transporters in patients with multiple system atrophy and Parkinson's disease

PURPOSE

Multiple system atrophy (MSA), a disorder causing autonomic dysfunction, parkinsonism, and cerebellar dysfunction, is difficult to differentiate from other movement disorders, particularly early in the course of disease. This study evaluated whether [99mTc]TRODAT-1 binding to the dopamine transporter differentiates MSA from other movement disorders.

METHODS

Single-photon emission computed tomographic brain scans were acquired in 25 MSA patients, 48 age-matched controls, and 130 PD patients, 3 h after the injection of 740 MBq (20 mCi) of [99mTc]TRODAT-1. Regions of interest (ROIs) were placed manually on subregions of both basal ganglia and distribution volume ratios (DVRs) were calculated. Regional DVRs were compared between study groups in MSA patients. Student's t tests were used to compare MSA patients with other study groups. Spearman correlations were used to compare DVRs with NP measures.

RESULTS

Based upon various motor scores, MSA and PD patients had comparable motor impairment, and were significantly impaired compared with controls. Mean DVRs in the basal ganglia of MSA patients were significantly less than those of controls, but generally higher (p<0.05) than in PD patients. In particular, the MSA patients had significantly increased DVRs in the posterior putamen (mean 0.49+/-0.30) compared with PD patients (0.74+/-0.25).

CONCLUSION

Movement disorder patients could be differentiated from controls, but MSA and PD patients could not be easily differentiated from each other. As a group, MSA patients had significantly higher mean [99mTc]TRODAT-1 binding, particularly in the posterior putamen, compared with PD patients and significantly lower binding compared with controls. This may reflect different pathophysiological processes of the two neurodegenerative diseases.

An R5L tau mutation in a subject with a progressive supranuclear palsy phenotype

MAPT, the gene encoding tau, was screened for mutations in 96 progressive supranuclear palsy subjects. A point mutation (R5L) was identified in a single progressive supranuclear palsy subject that was not in the other progressive supranuclear palsy subjects or in 96 controls. Functionally, this mutation alters the ability of tau to promote microtubule assembly. Analysis of soluble tau from different brain regions indicates that the mutation does not affect the ratio of tau isoforms synthesized. Aggregated insoluble tau from subcortical regions was predominantly four-repeat tau with no or one amino terminal insert (0N4R and 1N4R). Insoluble tau from cortical regions also contained 1N3R tau. Thus, the R5L mutation causes a progressive supranuclear palsy phenotype, presumably by a gain-of-function mechanism.

Targeting for thalamic deep brain stimulator implantation without computer guidance: assessment of targeting accuracy

The authors assess the accuracy of targeting nucleus ventralis intermedius (Vim) with fast spin echo inversion recovery (FSE/IR) magnetic resonance imaging (MRI) in 18 successful deep brain stimulator (DBS) implants for medically refractory tremor. FSE/IR-MRI-derived coordinates are compared to the final coordinates employed for DBS lead placement, selected with intraoperative neurophysiology. The authors conclude that FSE/IR MRI is sufficiently reliable to serve as the sole means of anatomically targeting Vim for DBS lead placement. An independent computer workstation is not required for accurate targeting; however, intraoperative neurophysiology remains essential.

A multicenter trial of ropinirole as adjunct treatment for Parkinson's disease. Ropinirole Study Group

OBJECTIVE

To evaluate the nonergot dopamine agonist ropinirole as an adjunct to L-dopa in a randomized, double-blind trial in PD patients with motor fluctuations.

BACKGROUND

L-dopa in the treatment of PD is associated with motor fluctuations, dyskinesia, and other adverse effects. The use of dopamine agonists in the treatment of PD delays recourse to L-dopa and thus delays the possibility of adverse effect onset.

METHODS

Ropinirole (n = 95) or placebo (n = 54) was added to L-dopa, and L-dopa was then reduced in a planned manner during the 6-month trial.

RESULTS

A significantly greater number of ropinirole patients were able to achieve a 20% or greater reduction in both L-dopa dose and in percent time spent "off" compared with placebo (35.0% versus 13.0%; p = 0.003). The mean daily L-dopa dose was reduced significantly with ropinirole treatment (242 mg versus 51 mg; p < 0.001) as was the percent awake time spent "off" (11.7% versus 5.1%; p = 0.039). There was no difference in the percent of patients who withdrew because of adverse effects (15.8% on ropinirole versus 16.7% on placebo).

CONCLUSIONS

Ropinirole permits a reduction in L-dopa dose with enhanced clinical benefit for PD patients with motor fluctuations.

Association of apolipoprotein epsilon 4 allele and neuropathologic findings in patients with dementia

Apolipoprotein E (APOE) is a lipoprotein expressed in liver and brain as one of three isoforms (APOE 2, APOE 3 and APOE 4). Recent findings suggest that the presence of APOE 4 is associated with an increased risk for both familial Alzheimer's disease and late-onset Alzheimer's disease. We extended these observations by determining the frequency of APOE alleles in patients with pathologically confirmed Alzheimer's Disease (AD), Parkinson's disease (PD), diffuse Lewy Body disease (DLBD), AD with concomitant PD pathology, demented PD patients without or with concomitant AD pathology and in schizophrenics with a progressive dementia (SCHIZ+DEM). The APOE genotype was determined by restriction digestion of polymerase chain reaction-amplified DNA isolated from frozen brain samples. The frequency of the APOE epsilon 4 allele was highest among sporadic AD and DLBD patients (0.30 and 0.38, respectively) and lowest in the SCHIZ+DEM and non-demented PD patients (0.06 and 0.1, respectively). Thus, the APOE epsilon 4 allele is over-represented selectively in patients with dementias associated with plaques and tangles and/or cortical Lewy bodies, but not in demented schizophrenics or non-demented PD patients.

Olfactory function in Parkinson's disease subtypes

Decreased olfactory function commonly occurs in idiopathic Parkinson's disease (PD), regardless of stage, treatment, or duration of disease. In the present study, we sought to determine whether different subtypes of PD, categorized according to well-defined clinical criteria, evidence different degrees of olfactory dysfunction. Significantly different scores on the University of Pennsylvania Smell Identification Test (UPSIT) were present between patients with benign PD and malignant PD (respective means [SD] = 22.51 [8.50] and 17.38 [6.29]) and between tremor-predominant PD and postural instability-gait disorder (PIGD)-predominant PD (23.43 [8.18] versus 17.35 [6.00]). No statistically significant differences in UPSIT scores were observed between young-onset and older-onset PD patients. Women outperformed men in most subtypes examined.

A multicenter double-blind placebo-controlled trial of pergolide as an adjunct to Sinemet in Parkinson's disease

Three hundred and seventy-six subjects with advanced Parkinson's disease participated in a prospective, double-blind placebo-controlled study of the dopamine agonist pergolide mesylate as an adjunct to Sinemet. At 6 months, patients randomized to pergolide had a statistically significant improvement in total Parkinson's score, scores of activities of daily living, motor function, number of "off" hours, Hoehn and Yahr stage, and numerous parameters of parkinsonian function including bradykinesia, rigidity, gait, and dexterity. This benefit was obtained with the addition of a mean dose of 2.94 mg of pergolide, which permitted a 24.7% reduction in dose of levodopa. Adverse reactions were, for the most part, mild, reversible, and not of major clinical significance. No significant cardiac or electrocardiographic abnormalities were detected. This study demonstrates that pergolide mesylate, as an adjunct to levodopa, is an effective antiparkinsonian agent that provides clinical improvement while permitting a reduction in levodopa dose.

Treatment of organic bipolar mood disorders in Parkinson's disease

Two patients with long-standing idiopathic Parkinson's disease (PD), without individual or family histories of affective disorders, developed bipolar mood disorders. Both were treated with lithium and clozapine, and one responded favorably. These may be the first reported cases in which mania was treated with clozapine in PD patients.

The epidemiology of Parkinson's disease. A case-control study of young-onset and old-onset patients

While the cause of Parkinson's disease (PD) remains unknown, recent evidence suggests that certain external factors, ie, environmental agents, may act as neurotoxins, initiating the chain of oxidative reactions that ultimately destroy neurons in the substantia nigra. Young-onset PD might result from greater exposure to a putative neurotoxin. This hypothesis has rekindled interest in the epidemiology of PD. We therefore conducted a detailed analysis of various environmental exposures and early life experiences in 80 patients with old-onset PD (at an age older than 60 years), 69 young-onset patients (younger than 40 years), and 149 age- and sex-matched control subjects. Contrary to previous reports, we were unable to implicate well water or exposure to herbicides, pesticides, or industrial toxins as significant PD risk factors. A residential history of rural living was reported by more patient cases than control subjects and was marginally significant. On the other hand, at least one episode of head trauma "severe enough to cause vertigo, dizziness, blurred or double vision, seizures or convulsions, transient memory loss, personality changes, or paralysis" occurred significantly more often prior to disease onset in patients with both young-onset and old-onset PD than in control subjects (odds ratio = 2.7). When adjusted for head trauma and rural living, smoking was inversely associated with PD, as has been previously reported (odds ratio = 0.5). There were no significant differences in early life experiences or environmental exposures between young-onset and old-onset patients. We suggest that the risk of developing PD is influenced by a variety of factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Postmortem analysis of adrenal-medulla-to-caudate autograft in a patient with Parkinson's disease

A 53-year-old physician who had a 10-year history of progressive idiopathic parkinsonism survived for 4 months after an autologous adrenal-medulla-to-right-caudate autograft but he received little clinical benefit. A small number of chromaffin cells in the graft site survived; they expressed neurofilament proteins and chromogranin A, but scant tyrosine hydroxylase. The striatum on both sides showed almost complete loss of [3H]mazindol binding to dopamine-uptake sites; the density of dopamine receptors was decreased adjacent to the transplant but increased rostral to the transplant. These results demonstrate that autografted chromaffin cells can survive for 4 months after transplantation and that related changes in dopamine receptors can be quantified.

Selective expression of epitopes in multiphosphorylation repeats of the high and middle molecular weight neurofilament proteins in Alzheimer neurofibrillary tangles

Here we review our recent "epitope analyses" of a few of the fibrous intraneuronal inclusions that are distinctive hallmarks of human neurodenerative conditions using a large library of monoclonal antibodies (MAbs) raised to normal neuronal cytoskeletal proteins. Analyses of the low (NF-L), middle (NF-M), and high (NF-M), and high (NF-H) molecular weight neurofilament (NF) proteins with greater than 500 MAbs enumerated epitopes shared by NF proteins and the intraneuronal neurofibrillary tangles (NFTs) that occur in the hippocampus and brainstem of Alzheimer's disease (AD) subjects. We identified the NF-H multi-phosphorylation repeat domain, i.e. repeats of Lys-Ser-Pro-X (where X is a small uncharged amino acid and Ser acts as a phosphate acceptor), as the determinant recognized by 15/16 MAbs that detected NFTs in sections of AD hippocampus, and 11 of the same 16 MAbs recognised NF-M multi-phosphorylation repeats. Further, the antigen binding regions of these MAbs were shown to comprise 13 separate classes based on their differential binding to 12 synthetic peptides derived from the NF-H and NF-M multi-phosphorylation sites, NF subunits of 10 diverse mammalian and sub-mammalian species, and normal human tau (tau). None of these anti-NF MAbs recognized NFTs in the brainstem of subjects with progressive supranuclear palsy (PSP), but NFTs in AD brainstem sections were reactive with five of these MAbs. Both PSP and AD brainstem NFTs were recognized by MAbs specific for tau and paired helical filament antigens.(ABSTRACT TRUNCATED AT 400 WORDS)