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1.  Activity enhances dopaminergic long-duration response in Parkinson disease 
Jung Kang, Un | Auinger, Peggy | Fahn, Stanley | Oakes, David | Shoulson, Ira | Kieburtz, Karl | Rudolph, Alice | Marek, Kenneth | Seibyl, John | Lang, Anthony | Olanow, C. Warren | Tanner, Caroline | Schifitto, Giovanni | Zhao, Hongwei | Reyes, Lydia | Shinaman, Aileen | Comella, Cynthia L. | Goetz, Christopher | Blasucci, Lucia M. | Samanta, Johan | Stacy, Mark | Williamson, Kelli | Harrigan, Mary | Greene, Paul | Ford, Blair | Moskowitz, Carol | Truong, Daniel D. | Pathak, Mayank | Jankovic, Joseph | Ondo, William | Atassi, Farah | Hunter, Christine | Jacques, Carol | Friedman, Joseph H. | Lannon, Margaret | Russell, David S. | Jennings, Danna | Fussell, Barbara | Standaert, David | Schwarzschild, Michael A. | Growdon, John H. | Tennis, Marsha | Gauthier, Serge | Panisset, Michel | Hall, Jean | Gancher, Stephen | Hammerstad, John P. | Stone, Claudia | Alexander-Brown, Barbara | Factor, Stewart A. | Molho, Eric | Brown, Diane | Evans, Sharon | Clark, Jeffrey | Manyam, Bala | Simpson, Patricia | Wulbrecht, Brian | Whetteckey, Jacqueline | Martin, Wayne | Roberts, Ted | King, Pamela | Hauser, Robert | Zesiewicz, Theresa | Gauger, Lisa | Trugman, Joel | Wooten, G. Frederick | Rost-Ruffner, Elke | Perlmutter, Joel | Racette, Brad A. | Suchowersky, Oksana | Ranawaya, Ranjit | Wood, Susan | Pantella, Carol | Kurlan, Roger | Richard, Irene | Pearson, Nancy | Caviness, John N. | Adler, Charles | Lind, Marlene | Simuni, Tanya | Siderowf, Andrew | Colcher, Amy | Lloyd, Mary | Weiner, William | Shulman, Lisa | Koller, William | Lyons, Kelly | Feldman, Robert G. | Saint-Hilaire, Marie H. | Ellias, Samuel | Thomas, Cathi-Ann | Juncos, Jorge | Watts, Ray | Partlow, Anna | Tetrud, James | Togasaki, Daniel M. | Stewart, Tracy | Mark, Margery H. | Sage, Jacob I. | Caputo, Debbie | Gould, Harry | Rao, Jayaraman | McKendrick, Ann | Brin, Mitchell | Danisi, Fabio | Benabou, Reina | Hubble, Jean | Paulson, George W. | Reider, Carson | Birnbaum, Alex | Miyasaki, Janis | Johnston, Lisa | So, Julie | Pahwa, Rajesh | Dubinsky, Richard M. | Wszolek, Zbigniew | Uitti, Ryan | Turk, Margaret | Tuite, Paul | Rottenberg, David | Hansen, Joy | Ramos, Serrano | Waters, Cheryl | Lew, Mark | Welsh, Mickie | Kawai, Connie | O'Brien, Christopher | Kumar, Rajeev | Seeberger, Lauren | Judd, Deborah | Barclay, C. Lynn | Grimes, David A. | Sutherland, Laura | Dawson, Ted | Reich, Stephen | Dunlop, Rebecca | Albin, Roger | Frey, Kirk | Wernette, Kristine | Fahn, Stanley | Oakes, David | Shoulson, Ira | Kieburtz, Karl | Rudolph, Alice | Marek, Kenneth | Seibyl, John | Lang, Anthony | Olanow, C. Warren | Tanner, Caroline | Schifitto, Giovanni | Zhao, Hongwei | Reyes, Lydia | Shinaman, Aileen | Comella, Cynthia L. | Goetz, Christopher | Blasucci, Lucia M. | Samanta, Johan | Stacy, Mark | Williamson, Kelli | Harrigan, Mary | Greene, Paul | Ford, Blair | Moskowitz, Carol | Truong, Daniel D. | Pathak, Mayank | Jankovic, Joseph | Ondo, William | Atassi, Farah | Hunter, Christine | Jacques, Carol | Friedman, Joseph H. | Lannon, Margaret | Russell, David S. | Jennings, Danna | Fussell, Barbara | Standaert, David | Schwarzschild, Michael A. | Growdon, John H. | Tennis, Marsha | Gauthier, Serge | Panisset, Michel | Hall, Jean | Gancher, Stephen | Hammerstad, John P. | Stone, Claudia | Alexander-Brown, Barbara | Factor, Stewart A. | Molho, Eric | Brown, Diane | Evans, Sharon | Clark, Jeffrey | Manyam, Bala | Simpson, Patricia | Wulbrecht, Brian | Whetteckey, Jacqueline | Martin, Wayne | Roberts, Ted | King, Pamela | Hauser, Robert | Zesiewicz, Theresa | Gauger, Lisa | Trugman, Joel | Wooten, G. Frederick | Rost-Ruffner, Elke | Perlmutter, Joel | Racette, Brad A. | Suchowersky, Oksana | Ranawaya, Ranjit | Wood, Susan | Pantella, Carol | Kurlan, Roger | Richard, Irene | Pearson, Nancy | Caviness, John N. | Adler, Charles | Lind, Marlene | Simuni, Tanya | Siderowf, Andrew | Colcher, Amy | Lloyd, Mary | Weiner, William | Shulman, Lisa | Koller, William | Lyons, Kelly | Feldman, Robert G. | Saint-Hilaire, Marie H. | Ellias, Samuel | Thomas, Cathi-Ann | Juncos, Jorge | Watts, Ray | Partlow, Anna | Tetrud, James | Togasaki, Daniel M. | Stewart, Tracy | Mark, Margery H. | Sage, Jacob I. | Caputo, Debbie | Gould, Harry | Rao, Jayaraman | McKendrick, Ann | Brin, Mitchell | Danisi, Fabio | Benabou, Reina | Hubble, Jean | Paulson, George W. | Reider, Carson | Birnbaum, Alex | Miyasaki, Janis | Johnston, Lisa | So, Julie | Pahwa, Rajesh | Dubinsky, Richard M. | Wszolek, Zbigniew | Uitti, Ryan | Turk, Margaret | Tuite, Paul | Rottenberg, David | Hansen, Joy | Ramos, Serrano | Waters, Cheryl | Lew, Mark | Welsh, Mickie | Kawai, Connie | O'Brien, Christopher | Kumar, Rajeev | Seeberger, Lauren | Judd, Deborah | Barclay, C. Lynn | Grimes, David A. | Sutherland, Laura | Dawson, Ted | Reich, Stephen | Dunlop, Rebecca | Albin, Roger | Frey, Kirk | Wernette, Kristine | Mendis, Tilak
Neurology  2012;78(15):1146-1149.
Objective:
We tested the hypothesis that dopamine-dependent motor learning mechanism underlies the long-duration response to levodopa in Parkinson disease (PD) based on our studies in a mouse model. By data-mining the motor task performance in dominant and nondominant hands of the subjects in a double-blind randomized trial of levodopa therapy, the effects of activity and dopamine therapy were examined.
Methods:
We data-mined the Earlier versus Later Levodopa Therapy in Parkinson's Disease (ELLDOPA) study published in 2005 and performed statistical analysis comparing the effects of levodopa and dominance of handedness over 42 weeks.
Results:
The mean change in finger-tapping counts from baseline before the initiation of therapy to predose at 9 weeks and 40 weeks increased more in the dominant compared to nondominant hand in levodopa-treated subjects in a dose-dependent fashion. There was no significant difference in dominant vs nondominant hands in the placebo group. The short-duration response assessed by the difference of postdose performance compared to predose performance at the same visit did not show any significant difference between dominant vs nondominant hands.
Conclusions:
Active use of the dominant hand and dopamine replacement therapy produces synergistic effect on long-lasting motor task performance during “off” medication state. Such effect was confined to dopamine-responsive symptoms and not seen in dopamine-resistant symptoms such as gait and balance. We propose that long-lasting motor learning facilitated by activity and dopamine is a form of disease modification that is often seen in trials of medications that have symptomatic effects.
doi:10.1212/WNL.0b013e31824f8056
PMCID: PMC3466780  PMID: 22459675
2.  Neuropsychological assessment in collaborative Parkinson’s disease research 
Cognitive impairment (CI) and behavioral disturbances can be the earliest symptoms of Parkinson’s disease (PD), ultimately afflict the vast majority of PD patients, and increase caregiver burden. Our two Morris K. Udall Centers of Excellence for Parkinson’s Disease Research were supported by the National Institute of Neurological Disorders and Stroke (NINDS) to recommend a comprehensive yet practical approach to cognitive and behavioral assessment to fuel collaborative research. We recommend a step-wise approach with two levels of standardized evaluation to establish a common battery, as well as an alternative testing recommendation for severely impaired subjects, and review supplemental tests that may be useful in specific research settings. Our flexible approach may be applied to studies with varying emphasis on cognition and behavior, does not place undue burden on participants or resources, and has a high degree of compatibility with existing test batteries to promote collaboration.
doi:10.1016/j.jalz.2012.07.006
PMCID: PMC3612566  PMID: 23164549
3.  Cognitive impairment and PD patients' capacity to consent to research 
Neurology  2013;81(9):801-807.
Objective:
To examine how cognitive impairment affects Parkinson disease (PD) patients' research consent capacity.
Methods:
A cross-sectional study of 90 patients with PD, divided using Mattis Dementia Rating Scale–2 scores into 3 groups of 30 (normal, borderline, and impaired), and 30 neurologically normal older adults completed 2 capacity interviews (an early-phase randomized and controlled drug trial and a sham-controlled surgical implantation of genetic tissue) using the MacArthur Competence Assessment Tool for Clinical Research. Expert clinicians used the interviews to classify the patients as either capable or not capable of providing their own informed consent. These judgments were compared with performance on the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE).
Results:
Cognitively normal PD patients typically scored well on the capacity measures. In contrast, patients with impaired cognition were not capable of providing their own informed consent: 17% (5/30) on the drug trial and 3% (1/30) on the surgery trial were judged capable. Patients with borderline impairment showed adequate performance on measures of appreciation and reasoning, but impaired performance on understanding the drug trial compared with normal controls and normal PD patients, and on understanding the surgery trial compared with normal controls. Sixty-seven percent (20/30) on the drug trial and 57% (17/30) on the surgery trial were judged capable of consent. Receiver operating characteristic analyses showed that the MMSE and MoCA could detect the likelihood of impaired capacity, with the MoCA demonstrating greater sensitivity.
Conclusions:
PD patients with borderline cognitive impairment have impairments in their decisional capacity. The MoCA may be useful to identify the patients at risk of impaired capacity.
doi:10.1212/WNL.0b013e3182a05ba5
PMCID: PMC3908465  PMID: 23892706
4.  Plasma Apolipoprotein A1 as a Biomarker for Parkinson's Disease 
Annals of neurology  2013;74(1):119-127.
Objective
To identify plasma-based biomarkers for Parkinson's Disease (PD) risk.
Methods
In a discovery cohort of 152 PD patients, plasma levels of 96 proteins were measured by multiplex immunoassay; proteins associated with age at PD onset were identified by linear regression. Findings from discovery screening were then assessed in a second cohort of 187 PD patients, using a different technique. Finally, in a third cohort of at-risk, asymptomatic individuals enrolled in the Parkinson's Associated Risk Study (PARS, n=134), plasma levels of the top candidate biomarker were measured, and dopamine transporter (DAT) imaging performed, to evaluate the association of plasma protein levels with dopaminergic system integrity.
Results
One of the best candidate protein biomarkers to emerge from discovery screening was apolipoprotein A1 (ApoA1, p=0.001). Low levels of ApoA1 correlated with earlier PD onset, with a 26% decrease in risk of developing PD associated with each tertile increase in ApoA1 (Cox proportional hazards p<0.001, hazard ratio=0.742). The association between plasma ApoA1 levels and age at PD onset replicated in an independent cohort of PD patients (p<0.001). Finally, in the PARS cohort of high-risk, asymptomatic subjects, lower plasma levels of ApoA1 were associated with greater putaminal DAT deficit (p=0.037).
Interpretation
Lower ApoA1 levels correlate with dopaminergic system vulnerability in symptomatic PD patients and in asymptomatic individuals with physiological reductions in dopamine transporter density consistent with prodromal PD. Plasma ApoA1 may be a new biomarker for PD risk.
doi:10.1002/ana.23872
PMCID: PMC3773265  PMID: 23447138
5.  Association of Cerebrospinal Fluid β-Amyloid 1-42, T-tau, P-tau181, and α-Synuclein Levels With Clinical Features of Drug-Naive Patients With Early Parkinson Disease 
JAMA neurology  2013;70(10):1277-1287.
Importance
We observed a significant correlation between cerebrospinal fluid (CSF) levels of tau proteins and α-synuclein, but not β-amyloid 1–42 (Aβ1–42), and lower concentration of CSF biomarkers, as compared with healthy controls, in a cohort of entirely untreated patients with Parkinson disease (PD) at the earliest stage of the disease studied so far.
Objective
To evaluate the baseline characteristics and relationship to clinical features of CSF biomarkers (Aβ1–42, total tau [T-tau], tau phosphorylated at threonine 181 [P-tau181], and α-synuclein) in drug-naive patients with early PD and demographically matched healthy controls enrolled in the Parkinson’s Progression Markers Initiative (PPMI) study.
Design, Setting, and Participants
Cross-sectional study of the initial 102 research volunteers (63 patients with PD and 39 healthy controls) of the PPMI cohort.
Main Outcomes and Measures
The CSF biomarkers were measured by INNO-BIA AlzBio3 immunoassay (Aβ1–42, T-tau, and P-tau181; Innogenetics Inc) or by enzyme-linked immunosorbent assay (α-synuclein). Clinical features including diagnosis, demographic characteristics, motor, neuropsychiatric, and cognitive assessments, and DaTscan were systematically assessed according to the PPMI study protocol.
Results
Slightly, but significantly, lower levels of Aβ1–42, T-tau, P-tau181, α-synuclein, and T-tau/Aβ1–42 were seen in subjects with PD compared with healthy controls but with a marked overlap between groups. Using multivariate regression analysis, we found that lower Aβ1–42 and P-tau181 levels were associated with PD diagnosis and that decreased CSF T-tau and α-synuclein were associated with increased motor severity. Notably, when we classified patients with PD by their motor phenotypes, lower CSF Aβ1–42 and P-tau181 concentrations were associated with the postural instability–gait disturbance–dominant phenotype but not with the tremor-dominant or intermediate phenotype. Finally, we found a significant correlation of the levels of α-synuclein with the levels of T-tau and P-tau181.
Conclusions and Relevance
In this first report of CSF biomarkers in PPMI study subjects, we found that measures of CSF Aβ1–42, T-tau, P-tau181, and α-synuclein have prognostic and diagnostic potential in early-stage PD. Further investigations using the entire PPMI cohort will test the predictive performance of CSF biomarkers for PD progression.
doi:10.1001/jamaneurol.2013.3861
PMCID: PMC4034348  PMID: 23979011
6.  PET imaging of amyloid with Florbetapir F 18 and PET imaging of dopamine degeneration with 18F-AV-133 (florbenazine) in patients with Alzheimer’s disease and Lewy body disorders 
BMC Neurology  2014;14:79.
Background
Biomarkers based on the underlying pathology of Alzheimer’s disease (AD) and Dementia with Lewy Bodies (DLB) have the potential to improve diagnosis and understanding of the substrate for cognitive impairment in these disorders. The objective of this study was to compare the patterns of amyloid and dopamine PET imaging in patients with AD, DLB and Parkinson’s disease (PD) using the amyloid imaging agent florbetapir F 18 and 18F-AV-133 (florbenazine), a marker for vesicular monamine type 2 transporters (VMAT2).
Methods
Patients with DLB and AD, Parkinson’s disease (PD) and healthy controls (HC) were recruited for this study. On separate days, subjects received intravenous injections of florbetapir, and florbenazine. Amyloid burden and VMAT2 density were assessed quantitatively and by binary clinical interpretation. Imaging results for both tracers were compared across the four individual diagnostic groups and for combined groups based on underlying pathology (AD/DLB vs. PD/HC for amyloid burden and PD/DLB vs. AD/HC for VMAT binding) and correlated with measures of cognition and parkinsonism.
Results
11 DLB, 10 AD, 5 PD, and 5 controls participated in the study. Amyloid binding was significantly higher in the combined AD/DLB patient group (n = 21) compared to the PD/HC groups (n = 10, mean SUVr: 1.42 vs. 1.07; p = 0.0006). VMAT2 density was significantly lower in the PD/DLB group (n = 16) compared to the AD/ HC group (n = 15; 1.83 vs. 2.97; p < 0.0001). Within the DLB group, there was a significant correlation between cognitive performance and striatal florbenazine binding (r = 0.73; p = 0.011).
Conclusions
The results of this study show significant differences in both florbetapir and florbenazine imaging that are consistent with expected pathology. In addition, VMAT density correlated significantly with cognitive impairment in DLB patients (ClinicalTrials.gov identifier: NCT00857506, registered March 5, 2009).
doi:10.1186/1471-2377-14-79
PMCID: PMC4027995  PMID: 24716655
PET imaging; Alzheimer’s disease; Parkinson’s disease; Biomarkers
7.  Impairment of script comprehension in Lewy body spectrum disorders 
Brain and language  2013;125(3):330-343.
A disabling impairment of higher-order language function can be seen in patients with Lewy body spectrum disorders such as Parkinson's disease (PD), Parkinson's disease dementia (PDD), and dementia with Lewy bodies (DLB). We focus on script comprehension in patients with Lewy body spectrum disorders. While scripts unfold sequentially, constituent events are thought to contain an internal organization. Executive dysfunction in patients with Lewy body spectrum disorders may interfere with comprehension of this internal structure. We examined 42 patients (30 non-demented PD and 12 mildly demented PDD/DLB patients) and 12 healthy seniors. We presented 22 scripts (e.g., “going fishing”), each consisting of six events. Pilot data from young controls provided the basis for organizing associated events into clusters and arranging them hierarchically into scripts. We measured accuracy and latency to judge the order of adjacent events in the same cluster versus adjacent events in different clusters. PDD/DLB patients were less accurate in their ordering judgments than PD patients and controls. Healthy seniors and PD patients were significantly faster to judge correctly the order of highly associated within-cluster event pairs relative to less closely associated different-cluster event pairs, while PDD/DLB patients did not consistently distinguish between these event-pair types. This relative insensitivity to the clustered-hierarchical organization of events was related to executive impairment and to frontal atrophy as measured by volumetric MRI. These findings extend prior work on script processing to patients with Lewy body spectrum disorders and highlight the potential impact of frontal/executive dysfunction on the daily lives of affected patients.
doi:10.1016/j.bandl.2013.02.006
PMCID: PMC3940934  PMID: 23566691
Parkinson's disease; Parkinson's disease dementia; Dementia with Lewy bodies; Frontal cortex; Executive function; Scripts; Organization; Discourse; Volumetric MRI
8.  Screening for impulse control symptoms in patients with de novo Parkinson disease 
Neurology  2013;80(2):176-180.
Objective:
To determine the frequency and correlates of impulse control and related behavior symptoms in patients with de novo, untreated Parkinson disease (PD) and healthy controls (HCs).
Methods:
The Parkinson's Progression Markers Initiative is an international, multisite, case-control clinical study conducted at 21 academic movement disorders centers. Participants were recently diagnosed, untreated PD patients (n = 168) and HCs (n = 143). The outcome measures were presence of current impulse control and related behavior symptoms based on recommended cutoff points for the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP)-Short Form.
Results:
There were 311 participants with complete QUIP data. Frequencies of impulse control and related behavior symptoms for patients with PD vs HCs were as follows: gambling (1.2% vs 0.7%), buying (3.0% vs 2.1%), sexual behavior (4.2% vs 3.5%), eating (7.1% vs 10.5%), punding (4.8% vs 2.1%), hobbyism (5.4% vs 11.9%), walkabout (0.6% vs 0.7%), and any impulse control or related behavior (18.5% vs 20.3%). In multivariable models, a diagnosis of PD was not associated with symptoms of any impulse control or related behavior (p ≥ 0.10 in all cases).
Conclusions:
PD itself does not seem to confer an increased risk for development of impulse control or related behavior symptoms, which further reinforces the reported association between PD medications and impulse control disorders in PD. Given that approximately 20% of patients with newly diagnosed PD report some impulse control or related behavior symptoms, long-term follow-up is needed to determine whether such patients are at increased risk for impulse control disorder development once PD medications are initiated.
doi:10.1212/WNL.0b013e31827b915c
PMCID: PMC3589192  PMID: 23296128
9.  Characteristics of patients misdiagnosed with Alzheimer’s disease and their medication use: an analysis of the NACC-UDS database 
BMC Geriatrics  2013;13:137.
Background
This study compared individuals whose clinical diagnosis of Alzheimer’s disease (AD) matched or did not match neuropathologic results at autopsy on clinical and functional outcomes (cognitive impairment, functional status and neuropsychiatric symptoms). The study also assessed the extent of potentially inappropriate medication use (using potentially unnecessary medications or potentially inappropriate prescribing) among misdiagnosed patients.
Methods
Longitudinal data from the National Alzheimer’s Coordinating Center Uniform Data Set (NACC-UDS, 2005–2010) and corresponding NACC neuropathological data were utilized to compare 88 misdiagnosed and 438 accurately diagnosed patients.
Results
Following adjustment of sociodemographic characteristics, the misdiagnosed were found to have less severe cognitive and functional impairment. However, after statistical adjustment for sociodemographics, dementia severity level, time since onset of cognitive decline and probable AD diagnosis at baseline, the groups significantly differed on only one outcome: the misdiagnosed were less likely to be depressed/dysphoric. Among the misdiagnosed, 18.18% were treated with potentially inappropriate medication. An additional analysis noted this rate could be as high as 67.10%.
Conclusions
Findings highlight the importance of making an accurate AD diagnosis to help reduce unnecessary treatment and increase appropriate therapy. Additional research is needed to demonstrate the link between potentially inappropriate treatment and adverse health outcomes in misdiagnosed AD patients.
doi:10.1186/1471-2318-13-137
PMCID: PMC3878261  PMID: 24354549
Alzheimer disease; Diagnosis; Misdiagnosis; Autopsy; Neuropathology
10.  Research on the Premotor Symptoms of Parkinson’s Disease: Clinical and Etiological Implications 
Environmental Health Perspectives  2013;121(11-12):1245-1252.
Background: The etiology and natural history of Parkinson’s disease (PD) are not well understood. Some non-motor symptoms such as hyposmia, rapid eye movement sleep behavior disorder, and constipation may develop during the prodromal stage of PD and precede PD diagnosis by years.
Objectives: We examined the promise and pitfalls of research on premotor symptoms of PD and developed priorities and strategies to understand their clinical and etiological implications.
Methods: This review was based on a workshop, Parkinson’s Disease Premotor Symptom Symposium, held 7–8 June 2012 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina.
Discussion: Research on premotor symptoms of PD may offer an excellent opportunity to characterize high-risk populations and to better understand PD etiology. Such research may lead to evaluation of novel etiological hypotheses such as the possibility that environmental toxicants or viruses may initiate PD pathogenesis in the gastrointestinal tract or olfactory bulb. At present, our understanding of premotor symptoms of PD is in its infancy and faces many obstacles. These symptoms are often not specific to PD and have low positive predictive value for early PD diagnosis. Further, the pathological bases and biological mechanisms of these premotor symptoms and their relevance to PD pathogenesis are poorly understood.
Conclusion: This is an emerging research area with important data gaps to be filled. Future research is needed to understand the prevalence of multiple premotor symptoms and their etiological relevance to PD. Animal experiments and mechanistic studies will further understanding of the biology of these premotor symptoms and test novel etiological hypothesis.
Citation: Chen H, Burton EA, Ross GW, Huang X, Savica R, Abbott RD, Ascherio A, Caviness JN, Gao X, Gray KA, Hong JS, Kamel F, Jennings D, Kirshner A, Lawler C, Liu R, Miller GW, Nussbaum R, Peddada SD, Comstock Rick A, Ritz B, Siderowf AD, Tanner CM, Tröster AI, Zhang J. 2013. Research on the premotor symptoms of Parkinson’s Disease: clinical and etiological implications. Environ Health Perspect 121:1245–1252; http://dx.doi.org/10.1289/ehp.1306967
doi:10.1289/ehp.1306967
PMCID: PMC3855519  PMID: 23933572
11.  Optimal Frequency for Measuring Health Care Resource Utilization in Parkinson’s Disease Using Participant Recall: The FS-TOO Resource Utilization Substudy 
Clinical therapeutics  2008;30(8):1553-1557.
Objective
The aim of this substudy was to determine the agreement between 2 approaches for measuring health care resource utilization (eg, number of hospital visits, number of primary care physician visits) in trial participants with Parkinson’s disease (PD).
Methods
A substudy of the 1-year multicenter futility trial of GPI-1485 and coenzyme Q10 (FS-TOO) was performed to assess health care resource utilization agreement by measuring participant utilization recall after 12 months versus measuring participant utilization recall at regular 3-month intervals. Trial participants were selected from patients in the National Institutes of Health-sponsored FS-TOO multicenter study. Persons aged ≥30 years with confirmed PD diagnosis within the previous 5 years were eligible for inclusion in the substudy. Participants were also required to have at least 2 of 3 cardinal manifestations of PD (tremor, rigidity, and bradykinesia). Participants were excluded from the study if they had presence of atypical Parkinson’s syndromes due to drugs, metabolic identified neurogenetic disorders, encephalitis, or other degenerative diseases. Agreement was determined using Lin’s concordance and Cohen’s kappa statistics.
Results
Between March and July of 2004, a total of 424 potential subjects were identified and evaluated for trial eligibility. Of these, 213 subjects (139 men, 74 women; mean [SD] age, 61.5 [10.3] years) met entry criteria and were included in the study. Trial participants were randomized equally to 1 of 3 groups. The 3 groups had similar baseline characteristics in terms of demographic data (age, race, sex, employment status, and annual income), total Unified Parkinson Disease Rating Scale (UPDRS) score, and UPDRS subscores. In this substudy, 141 participants had a true baseline visit, indicating a clinical baseline date, and 182 participants completed the Baseline Resource Utilization Form within 3 months of the true baseline visit. The comparison of concordance between the summed information over 3-month recalls and the 12-month recall from baseline was derived from these 182 participants. The level of agreement between the 2 approaches was high, ranging from 64.4% to 95.1%. Where disagreement was identified, the more frequent measurement approach (every 3 months) led to higher estimates, ranging from 20.4% to 77.4%.
Conclusion
The results of this trial indicate internal consistency with the self-reported measures of health care resource utilization, suggesting that these simple measures might provide reliable information about units of health care resource utilization in the context of clinical trials for PD.
doi:10.1016/j.clinthera.2008.08.001
PMCID: PMC3773694  PMID: 18803996
health care resources; Parkinson’s disease; clinical trials
12.  Daytime sleepiness is associated with falls in Parkinson’s disease 
Journal of Parkinson's disease  2013;3(3):387-391.
Falls are frequent in Parkinson’s disease (PD), and may be influenced by daytime sleepiness. We reviewed the records of 120 men with PD. Mean Epworth Sleepiness Scale (ESS) values were significantly different between non-fallers and fallers (6.0 vs. 9.7, p<0.01). In multivariate analysis, ESS remained significantly associated with falls (OR 1.2, 95% CI 1.1–1.4, p=0.02), along with cognitive impairment (OR 4.4 95% CI 1.0–18.7, p=0.04) and postural instability/gait dysfunction (OR 1.6 95% CI 1.0–2.4, p=0.03) in non-depressed patients. In conclusion, non-depressed PD patients are 20% more likely to fall for every one unit increase in the ESS measure of sleepiness.
doi:10.3233/JPD-130184
PMCID: PMC3772981  PMID: 23948992
Parkinson’s disease; falls; sleepiness; depression; cognitive impairment
13.  Can a screening questionnaire accurately identify Mild Parkinsonian Signs? 
Neuroepidemiology  2012;39(3-4):171-175.
Background
Mild Parkinsonian Signs (MPS) are early features that, when present, increase risk of neurodegenerative disease and mortality. Current methods to identify MPS are limited to neurological examination. Our objective was to assess the ability of a 9-item Parkinson’s Disease Screening Questionnaire (PDSQ), which has high sensitivity in the detection of overt Parkinson’s disease (PD), to detect Mild Parkinsonian Signs.
Methods
Measures including the PDSQ, Unified Parkinson’s Disease Rating Scale and University of Pennsylvania Smell Identification Test were administered to 267 participants without neurodegenerative disease. Two published definitions of MPS were used to classify cases.
Results
PDSQ scores were higher for cases compared to controls (p < 0.001 for the first case definition and 0.07 for the second). However, the questionnaire had low sensitivity (47 and 59%) and specificity (62 and 63%) in the detection of MPS. Adding factors such as age, gender, and smell test score to the questionnaire in a predictive model only marginally improved the test characteristics.
Conclusion
The results show the screening questionnaire does not accurately identify Mild Parkinsonian Signs. More accurate tests are needed to improve detection of this early syndrome which can lead to motor disability, neurodegenerative disease and mortality.
doi:10.1159/000341409
PMCID: PMC3513756  PMID: 22948126
Mild Parkinsonian Signs; screening questionnaire; validity; sensitivity; specificity
14.  Plasma multianalyte profiling in mild cognitive impairment and Alzheimer disease 
Neurology  2012;79(9):897-905.
Objectives:
While plasma biomarkers have been proposed to aid in the clinical diagnosis of Alzheimer disease (AD), few biomarkers have been validated in independent patient cohorts. Here we aim to determine plasma biomarkers associated with AD in 2 independent cohorts and validate the findings in the multicenter Alzheimer's Disease Neuroimaging Initiative (ADNI).
Methods:
Using a targeted proteomic approach, we measured levels of 190 plasma proteins and peptides in 600 participants from 2 independent centers (University of Pennsylvania, Philadelphia; Washington University, St. Louis, MO), and identified 17 analytes associated with the diagnosis of very mild dementia/mild cognitive impairment (MCI) or AD. Four analytes (apoE, B-type natriuretic peptide, C-reactive protein, pancreatic polypeptide) were also found to be altered in clinical MCI/AD in the ADNI cohort (n = 566). Regression analysis showed CSF Aβ42 levels and t-tau/Aβ42 ratios to correlate with the number of APOE4 alleles and plasma levels of B-type natriuretic peptide and pancreatic polypeptide.
Conclusion:
Four plasma analytes were consistently associated with the diagnosis of very mild dementia/MCI/AD in 3 independent clinical cohorts. These plasma biomarkers may predict underlying AD through their association with CSF AD biomarkers, and the association between plasma and CSF amyloid biomarkers needs to be confirmed in a prospective study.
doi:10.1212/WNL.0b013e318266fa70
PMCID: PMC3425844  PMID: 22855860
15.  Costs of Parkinson’s Disease in a Privately Insured Population 
Pharmacoeconomics  2013;31(9):799-806.
Background
This is the first analysis to estimate the costs of commercially insured patients with Parkinson’s disease (PD) in the USA. Prior analyses of PD have not examined costs in patients aged under 65 years, a majority of whom are in the workforce.
Objective
Our objective was to estimate direct and indirect costs associated with PD in patients under the age of 65 years who are newly diagnosed or have evidence of advanced PD.
Methods
PD patients were selected from a commercially insured claims database (N > 12,000,000; 1999–2009); workloss data were available for a sub-sample of enrollees. Newly diagnosed patients with evidence of similar disorders were excluded. Patients with evidence of advanced PD disease, including ambulatory assistance device users (PDAAD) and institutionalized (PDINST) patients, as well as newly diagnosed PD patients, were analyzed. Each PD cohort was age-, gender- and region-matched to controls without PD. Direct (i.e. insurer payments to providers) and indirect (i.e. workloss) costs were reported in $US, year 2010 values, and were descriptively compared using Wilcoxon rank sum tests.
Results
Patients had excess mean direct PD-related costs of $US4,072 (p < 0.001; N = 781) in the year after diagnosis. The PDAAD cohort (N = 214) had excess direct PD-related costs of $US26,467 (p < 0.001) and the PDINST cohort (N = 156) had excess direct PD-related costs of $US37,410 (p < 0.001) in the year after entering these states. Outpatient care was the most expensive cost source for newly diagnosed patients, while inpatient care was the most expensive for PDAAD and PDINST patients. Excess indirect costs were $US3,311 (p < 0.05; N = 173) in the year after initial diagnosis.
Conclusions
Direct costs for newly diagnosed PD patients exceeded costs for controls without PD, and increased with PD progression. Direct costs were approximately 6–7 times higher in patients with advanced PD than in matched controls. Indirect costs represented 45 % of total excess costs for newly diagnosed PD patients.
doi:10.1007/s40273-013-0075-0
PMCID: PMC3757266  PMID: 23907717
16.  Pre-Motor Parkinson’s Disease: Concepts and Definitions 
Movement Disorders  2012;27(5):608-616.
Parkinson’s disease (PD) has a prodromal phase during which non-motor clinical features as well as physiological abnormalities may be present. These pre-motor markers could be used to screen for PD before motor abnormalities are present. The technology to identify PD before it reaches symptomatic Braak Stage 3 (substantia nigra compacta (SNc) involvement) already exists. The current challenge is to define the appropriate scope of use of predictive testing for PD. Imaging technologies, like dopamine transporter imaging, currently offer the highest degree of accuracy for identifying pre-motor PD, but they are expensive as screening tools and abnormalities on these studies would only be evident at Braak Stage 3 or higher. Efficiency is greatly enhanced by combining imaging with a pre-screening test, such as olfactory testing. This two-step process has the potential to greatly reduce costs while retaining diagnostic accuracy. Alternatively, or in concert with this approach, evaluating high-risk populations (e.g. patients with rapid eye movement behavior disorder (RBD) or LRRK2 mutations) would enrich the sample for cases with underlying PD. Ultimately, the role of pre-clinical detection of PD will be determined by the ability of emerging therapies to influence clinical outcomes. As such, implementation of large-scale screening strategies awaits the arrival of clearly safe and effective therapies that address the underlying pathogenesis of PD. Future research will establish more definitive biomarkers capable of revealing the presence of disease in advance of SNc involvement with the promise of the potential for introducing disease modifying therapy even before the development of evidence for dopamine deficiency.
doi:10.1002/mds.24954
PMCID: PMC3335740  PMID: 22508279
Parkinson’s disease; early detection; sensitivity; specificity
17.  Mapping the EQ-5D index by UPDRS and PDQ-8 in patients with Parkinson’s disease 
Background
Clinical studies employ the Unified Parkinson’s Disease Rating Scale (UPDRS) to measure the severity of Parkinson’s disease. Evaluations often fail to consider the health-related quality of life (HrQoL) or apply disease-specific instruments. Health-economic studies normally use estimates of utilities to calculate quality-adjusted life years. We aimed to develop an estimation algorithm for EuroQol- 5 dimensions (EQ-5D)-based utilities from the clinical UPDRS or disease-specific HrQoL data in the absence of original utilities estimates.
Methods
Linear and fractional polynomial regression analyses were performed with data from a study of Parkinson’s disease patients (n=138) to predict the EQ-5D index values from UPDRS and Parkinson’s disease questionnaire eight dimensions (PDQ-8) data. German and European weights were used to calculate the EQ-5D index. The models were compared by R2, the root mean square error (RMS), the Bayesian information criterion, and Pregibon’s link test. Three independent data sets validated the models.
Results
The regression analyses resulted in a single best prediction model (R2: 0.713 and 0.684, RMS: 0.139 and 13.78 for indices with German and European weights, respectively) consisting of UPDRS subscores II, III, IVa-c as predictors. When the PDQ-8 items were utilised as independent variables, the model resulted in an R2 of 0.60 and 0.67. The independent data confirmed the prediction models.
Conclusion
The best results were obtained from a model consisting of UPDRS subscores II, III, IVa-c. Although a good model fit was observed, primary EQ-5D data are always preferable. Further validation of the prediction algorithm within large, independent studies is necessary prior to its generalised use.
doi:10.1186/1477-7525-11-35
PMCID: PMC3662160  PMID: 23497005
Parkinson’s disease; Quality of life; EuroQoL/EQ-5D; UPDRS; PDQ-8; Prediction
18.  Screening Questionnaires for Parkinsonism: A Systematic Review 
Parkinsonism & related disorders  2011;18(3):216-224.
Parkinson’s disease (PD) is a common, treatable movement disorder that often remains undiagnosed despite clinically manifest symptoms. Screening for parkinsonism could lead to improved detection and earlier treatment, and facilitate research studies of PD prevalence. In order to determine the feasibility of screening, this study evaluated the validity of previously developed screening questionnaires. We systematically searched online databases PubMed and EMBASE for English-language studies published between 1980 and 2009. In each database a “Parkinson(s) disease” or “parkinsonism” term was combined with a screening term (“screening instrument,” screening questionnaire,” “screen” or “prevalence survey”) and a validity term (“validation,” “sensitivity” and “specificity”). Included studies reported the psychometric properties of at least one self-report questionnaire for parkinsonism. Twenty-seven studies met the inclusion criteria. From these studies, 9 screening questionnaires were identified. Sensitivity and specificity estimates varied widely. Sensitivity estimates were as high as 100% when questionnaires were tested among previously diagnosed PD patients and included a high number of parkinsonism-specific items, but were as low as 48% when tested among early cases in a community-based sample. Specificity estimates were lower, ranging from 22–100%. An older sample, presence of multiple co-morbid conditions and lower literacy led to lower specificity estimates. Higher specificity estimates were seen when the screening questionnaires were administered by a physician. Screening questionnaires can detect symptomatic parkinsonism. However, the performance of these questionnaires varied based on the individual items, study sample, and method of administration. The performance of screening questionnaires in the detection of early or mild parkinsonism was modest.
doi:10.1016/j.parkreldis.2011.09.003
PMCID: PMC3253331  PMID: 21930414
Parkinson’s disease; early detection; instruments; sensitivity; specificity
19.  SENTENCE PROCESSING IN LEWY BODY SPECTRUM DISORDER: THE ROLE OF WORKING MEMORY 
Brain and Cognition  2012;78(2):85-93.
Prior work has related sentence processing to executive deficits in non-demented patients with Parkinson’s disease (PD). We extended this investigation to patients with dementia with Lewy bodies (DLB) and PD dementia (PDD) by examining grammatical and working memory components of sentence processing in the full range of patients with Lewy body spectrum disorder (LBSD). Thirty-three patients with LBSD were given a two-alternative, forced-choice sentence-picture matching task. Sentence type, working memory, and grammatical structure were systematically manipulated in the sentences. We found that patients with PDD and DLB were significantly impaired relative to non-demented PD patients and healthy controls. The deficit in PDD/DLB was most pronounced for sentences lengthened by the strategic placement of an additional prepositional phrase and for sentences with an additional proposition due to a center-embedded clause. However, there was no effect for subject-relative versus object-relative grammatical structure. An MRI voxel-based morphometry analysis in a subset of patients showed significant gray matter thinning in the frontal lobe bilaterally, and this extended to temporal, parietal and occipital regions. A regression analysis related sentence processing difficulty in LBSD to frontal neocortex, including inferiorprefrontal, premotor, and dorsolateral prefrontal regions, as well as right superior temporal cortex. These findings are consistent with the hypothesis that patients with PDD and DLB have difficulty processing sentences with increased working memory demands and that this deficit is related in part to their frontal disease.
doi:10.1016/j.bandc.2011.12.004
PMCID: PMC3265703  PMID: 22218297
Lewy body; Parkinson’s; sentence processing; working memory; MRI; prefrontal
20.  Impairments of Speech Fluency in Lewy Body Spectrum Disorder 
Brain and Language  2011;120(3):290-302.
Few studies have examined connected speech in demented and non-demented patients with Parkinson’s disease (PD). We assessed the speech production of 35 patients with Lewy body spectrum disorder (LBSD), including non-demented PD patients, patients with PD dementia (PDD), and patients with dementia with Lewy bodies (DLB), in a semi-structured narrative speech sample in order to characterize impairments of speech fluency and to determine the factors contributing to reduced speech fluency in these patients. Both demented and non-demented PD patients exhibited reduced speech fluency, characterized by reduced overall speech rate and long pauses between sentences. Reduced speech rate in LBSD correlated with measures of between-utterance pauses, executive functioning, and grammatical comprehension. Regression analyses related non-fluent speech, grammatical difficulty, and executive difficulty to atrophy in frontal brain regions. These findings indicate that multiple factors contribute to slowed speech in LBSD, and this is mediated in part by disease in frontal brain regions.
doi:10.1016/j.bandl.2011.09.004
PMCID: PMC3299896  PMID: 22099969
Parkinson’s disease; speech; language; fluency; dementia with Lewy bodies
21.  Questionnaire for Impulsive-Compulsive Disorders in Parkinson’s Disease–Rating Scale 
Impulse control disorders and related disorders (hobbyism-punding and dopamine dysregulation syndrome) occur in 15% to 20% of Parkinson’s disease (PD) patients. We assessed the validity and reliability of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson’s Disease–Rating Scale (QUIP-RS), a rating scale designed to measure severity of symptoms and support a diagnosis of impulse control disorders and related disorders in PD. A convenience sample of PD patients at a movement disorders clinic self-completed the QUIP-RS and were administered a semistructured diagnostic interview by a blinded trained rater to assess discriminant validity for impulse control disorders (n = 104) and related disorders (n = 77). Subsets of patients were assessed to determine interrater reliability (n = 104), retest reliability (n = 63), and responsiveness to change (n = 29). Adequate cutoff points (both sensitivity and specificity values >80% plus acceptable likelihood ratios) were established for each impulse control disorder and hobbyism-punding. Interrater and retest reliability (intraclass correlation coefficient r) were >0.60 for all disorders. Participants in an impulse control disorder treatment study who experienced full (t = 3.65, P = .004) or partial (t = 2.98, P = .01) response demonstrated significant improvement on the rating scale over time, while nonresponders did not (t = 0.12, P = .91). The QUIP-RS appears to be valid and reliable as a rating scale for impulse control disorders and related disorders in PD. Preliminary results suggest that it can be used to support a diagnosis of these disorders, as well as to monitor changes in symptom severity over time.
doi:10.1002/mds.24023
PMCID: PMC3537263  PMID: 22134954
dopamine agonists; impulse control disorder; Parkinson’s disease
22.  DIFFICULTY PROCESSING TEMPORARY SYNTACTIC AMBIGUITIES IN LEWY BODY SPECTRUM DISORDER 
Brain and Language  2011;120(1):52-60.
While grammatical aspects of language are preserved, executive deficits are prominent in Lewy body spectrum disorder (LBSD), including Parkinson’s disease (PD), Parkinson’s dementia (PDD) and dementia with Lewy bodies (DLB). We examined executive control during sentence processing in LBSD by assessing temporary structural ambiguities. Using an on-line word detection procedure, patients heard sentences with a syntactic structure that has high-compatibility or low-compatibility with the main verb’s statistically preferred syntactic structure, and half of the sentences were lengthened strategically between the onset of the ambiguity and its resolution. We found selectively slowed processing of lengthened ambiguous sentences in the PDD/DLB subgroup. This correlated with impairments on measures of executive control. Regression analyses related the working memory deficit during ambiguous sentence processing to significant cortical thinning in frontal and parietal regions. These findings emphasize the role of prefrontal disease in the executive limitations that interfere with processing ambiguous sentences in LBSD.
doi:10.1016/j.bandl.2011.08.007
PMCID: PMC3253921  PMID: 21962945
Parkinson’s; Lewy body; syntactic ambiguity; working memory; frontal
23.  Alzheimer's disease pattern of brain atrophy predicts cognitive decline in Parkinson's disease 
Brain  2011;135(1):170-180.
Research suggests overlap in brain regions undergoing neurodegeneration in Parkinson's and Alzheimer's disease. To assess the clinical significance of this, we applied a validated Alzheimer's disease-spatial pattern of brain atrophy to patients with Parkinson's disease with a range of cognitive abilities to determine its association with cognitive performance and decline. At baseline, 84 subjects received structural magnetic resonance imaging brain scans and completed the Dementia Rating Scale-2, and new robust and expanded Dementia Rating Scale-2 norms were applied to cognitively classify participants. Fifty-nine non-demented subjects were assessed annually with the Dementia Rating Scale-2 for two additional years. Magnetic resonance imaging scans were quantified using both a region of interest approach and voxel-based morphometry analysis, and a method for quantifying the presence of an Alzheimer's disease spatial pattern of brain atrophy was applied to each scan. In multivariate models, higher Alzheimer's disease pattern of atrophy score was associated with worse global cognitive performance (β = −0.31, P = 0.007), including in non-demented patients (β = −0.28, P = 0.05). In linear mixed model analyses, higher baseline Alzheimer's disease pattern of atrophy score predicted long-term global cognitive decline in non-demented patients [F(1, 110) = 9.72, P = 0.002], remarkably even in those with normal cognition at baseline [F(1, 80) = 4.71, P = 0.03]. In contrast, in cross-sectional and longitudinal analyses there was no association between region of interest brain volumes and cognitive performance in patients with Parkinson's disease with normal cognition. These findings support involvement of the hippocampus and parietal–temporal cortex with cognitive impairment and long-term decline in Parkinson's disease. In addition, an Alzheimer's disease pattern of brain atrophy may be a preclinical biomarker of cognitive decline in Parkinson's disease.
doi:10.1093/brain/awr277
PMCID: PMC3316476  PMID: 22108576
Alzheimer's disease; dementia; mild cognitive impairment; Parkinson's disease; neurodegeneration
24.  Neurodegeneration Across Stages of Cognitive Decline in Parkinson Disease 
Archives of Neurology  2011;68(12):1562-1568.
Objective
To assess regions and patterns of brain atrophy in patients with Parkinson disease (PD) with normal cognition (PD-NC), mild cognitive impairment (PD-MCI), and dementia-level cognitive deficits (PDD).
Design
Images were quantified using a region-of-interest approach and voxel-based morphometry analysis. We used a high-dimensional pattern classification approach to delineate brain regions that collectively formed the Spatial Pattern of Abnormalities for Recognition of PDD.
Setting
The Parkinson’s Disease and Movement Disorders Center at the University of Pennsylvania.
Subjects
Eighty-four PD patients (61 PD-NC, 12 PD-MCI, and 11 PDD) and 23 healthy control subjects (HCs) underwent magnetic resonance imaging of the brain.
Results
The PD-NC patients did not demonstrate significant brain atrophy compared with HCs. Compared with PD-NC patients, PD-MCI patients had hippocampal atrophy (β=−0.37; P=.001), and PDD patients demonstrated hippocampal (β=−0.32; P=.004) and additional medial temporal lobe atrophy (β=−0.36; P=.003). The PD-MCI patients had a different pattern of atrophy compared with PD-NC patients (P=.04) and a similar pattern to that of PDD patients (P=.81), characterized by hippocampal, prefrontal cortex gray and white matter, occipital lobe gray and white matter, and parietal lobe white matter atrophy. In nondemented PD patients, there was a correlation between memory-encoding performance and hippocampal volume.
Conclusions
Hippocampal atrophy is a biomarker of initial cognitive decline in PD, including impaired memory encoding and storage, suggesting heterogeneity in the neural substrate of memory impairment. Use of a pattern classification approach may allow identification of diffuse regions of cortical gray and white matter atrophy early in the course of cognitive decline.
doi:10.1001/archneurol.2011.725
PMCID: PMC3290902  PMID: 22159053
25.  The Organization of Narrative Discourse in Lewy Body Spectrum Disorder 
Brain and language  2011;119(1):30-41.
Narrative discourse is an essential component of day-to-day communication, but little is known about narrative in Lewy Body spectrum disorder (LBSD), including Parkinson's disease (PD), Parkinson's disease with dementia (PDD), and dementia with Lewy bodies (DLB). We performed a detailed analysis of a semi-structured speech sample in 32 non-aphasic patients with LBSD, and we related their narrative impairments to gray matter (GM) atrophy using voxel-based morphometry. We found that patients with PDD and DLB have significant difficulty organizing their narrative speech. This was correlated with deficits on measures of executive functioning and speech fluency. Regression analyses associated this deficit with reduced cortical volume in inferior frontal and anterior cingulate regions. These findings are consistent with a model of narrative discourse that includes executive as well as language components and with an impairment of the organizational component of narrative discourse in patients with PDD and DLB.
doi:10.1016/j.bandl.2011.05.006
PMCID: PMC3163000  PMID: 21689852
Parkinson's disease; discourse; speech; language; Dementia with Lewy bodies

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