Can a screening questionnaire accurately identify mild Parkinsonian signs?

BACKGROUND

Mild parkinsonian signs (MPS) are early features that, when present, increase the 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 MPS.

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 MPS. More accurate tests are needed to improve the detection of this early syndrome which can lead to motor disability, neurodegenerative disease and mortality.

Plasma multianalyte profiling in mild cognitive impairment and Alzheimer disease

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.

Neuro-QOL: brief measures of health-related quality of life for clinical research in neurology

OBJECTIVE

To address the need for brief, reliable, valid, and standardized quality of life (QOL) assessment applicable across neurologic conditions.

METHODS

Drawing from larger calibrated item banks, we developed short measures (8-9 items each) of 13 different QOL domains across physical, mental, and social health and evaluated their validity and reliability. Three samples were utilized during short form development: general population (Internet-based, n = 2,113); clinical panel (Internet-based, n = 553); and clinical outpatient (clinic-based, n = 581). All short forms are expressed as T scores with a mean of 50 and SD of 10.

RESULTS

Internal consistency (Cronbach α) of the 13 short forms ranged from 0.85 to 0.97. Correlations between short form and full-length item bank scores ranged from 0.88 to 0.99 (0.82-0.96 after removing common items from banks). Online respondents were asked whether they had any of 19 different chronic health conditions, and whether or not those reported conditions interfered with ability to function normally. All short forms, across physical, mental, and social health, were able to separate people who reported no health condition from those who reported 1-2 or 3 or more. In addition, scores on all 13 domains were worse for people who acknowledged being limited by the health conditions they reported, compared to those who reported conditions but were not limited by them.

CONCLUSION

These 13 brief measures of self-reported QOL are reliable and show preliminary evidence of concurrent validity inasmuch as they differentiate people based upon number of reported health conditions and whether those reported conditions impede normal function.

Premotor Parkinson's disease: concepts and definitions

Parkinson's disease (PD) has a prodromal phase during which nonmotor clinical features as well as physiological abnormalities may be present. These premotor 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 such as dopamine transporter imaging currently offer the highest degree of accuracy for identifying premotor 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 prescreening test such as olfactory testing. This 2-step process has the potential to greatly reduce costs while retaining diagnostic accuracy. Alternatively, or in concert with this approach, evaluating high-risk populations (eg, patients with rapid eye movement behavior disorder or LRRK2 mutations) would enrich the sample for cases with underlying PD. Ultimately, the role of preclinical 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 of dopamine deficiency.

Cognitive performance of GBA mutation carriers with early-onset PD: the CORE-PD study

OBJECTIVE

To assess the cognitive phenotype of glucocerebrosidase (GBA) mutation carriers with early-onset Parkinson disease (PD).

METHODS

We administered a neuropsychological battery and the University of Pennsylvania Smell Identification Test (UPSIT) to participants in the CORE-PD study who were tested for mutations in PARKIN, LRRK2, and GBA. Participants included 33 GBA mutation carriers and 60 noncarriers of any genetic mutation. Primary analyses were performed on 26 GBA heterozygous mutation carriers without additional mutations and 39 age- and PD duration-matched noncarriers. Five cognitive domains, psychomotor speed, attention, memory, visuospatial function, and executive function, were created from transformed z scores of individual neuropsychological tests. Clinical diagnoses (normal, mild cognitive impairment [MCI], dementia) were assigned blind to genotype based on neuropsychological performance and functional impairment as assessed by the Clinical Dementia Rating (CDR) score. The association between GBA mutation status and neuropsychological performance, CDR, and clinical diagnoses was assessed.

RESULTS

Demographics, UPSIT, and Unified Parkinson's Disease Rating Scale-III performance did not differ between GBA carriers and noncarriers. GBA mutation carriers performed more poorly than noncarriers on the Mini-Mental State Examination (p = 0.035), and on the memory (p = 0.017) and visuospatial (p = 0.028) domains. The most prominent differences were observed in nonverbal memory performance (p < 0.001). Carriers were more likely to receive scores of 0.5 or higher on the CDR (p < 0.001), and a clinical diagnosis of either MCI or dementia (p = 0.004).

CONCLUSION

GBA mutation status may be an independent risk factor for cognitive impairment in patients with PD.

Impaired olfaction and other prodromal features in the Parkinson At-Risk Syndrome Study

To test the association between impaired olfaction and other prodromal features of PD in the Parkinson At-Risk Syndrome Study. The onset of olfactory dysfunction in PD typically precedes motor features, suggesting that olfactory testing could be used as a screening test. A combined strategy that uses other prodromal nonmotor features, along with olfactory testing, may be more efficient than hyposmia alone for detecting the risk of PD. Individuals with no neurological diagnosis completed a mail survey, including the 40-item University of Pennsylvania Smell Identification Test, and questions on prodromal features of PD. The frequency of reported nonmotor features was compared across individuals with and without hyposmia. A total of 4,999 subjects completed and returned the survey and smell test. Of these, 669 were at or below the 15th percentile based on age and gender, indicating hyposmia. Hyposmics were significantly more likely to endorse nonmotor features, including anxiety and depression, constipation, and rapid eye movement sleep behavior disorder symptoms, and to report changes in motor function. Twenty-six percent of subjects with combinations of four or more nonmotor features were hyposmic, compared to 12% for those reporting three or fewer nonmotor features (P < 0.0001). Hyposmia is associated with other nonmotor features of PD in undiagnosed individuals. Further assessment of hyposmic subjects using more specific markers for degeneration, such as dopamine transporter imaging, will evaluate whether combining hyposmia and other nonmotor features is useful in assessing the risk of future neurodegeneration.

Impairments of speech fluency in Lewy body spectrum disorder

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.

Sentence processing in Lewy body spectrum disorder: the role of working memory

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 inferior prefrontal, 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.

Genetic influences on cognitive decline in Parkinson's disease

The role of genetic factors in cognitive decline associated with Parkinson's disease (PD) is unclear. We examined whether variations in apolipoprotein E (APOE), microtubule-associated protein tau (MAPT), or catechol-O-methytransferase (COMT) genotypes are associated with cognitive decline in PD. We performed a prospective cohort study of 212 patients with a clinical diagnosis of PD. The primary outcome was change in Mattis Dementia Rating Scale version 2 score. Linear mixed-effects models and survival analysis were used to test for associations between genotypes and change in cognitive function over time. The ε4 allele of APOE was associated with more rapid decline (loss of 2.9; 95% confidence interval [CI]: 1.7-4.1) of more points per year; P < 0.001) in total score and an increased risk of a ≥ 10 point drop during the follow-up period (hazard ratio, 2.8; 95% CI: 1.4-5.4; P = 0.003). MAPT haplotype and COMT genotype were associated with measures of memory and attention, respectively, over the entire follow-up period, but not with the overall rate of cognitive decline. These results confirm and extend previously described genetic associations with cognitive decline in PD and imply that individual genes may exert effects on specific cognitive domains or at different disease stages. Carrying at least one APOE ε4 allele is associated with more rapid cognitive decline in PD, supporting the idea of a component of shared etiology between PD dementia and Alzheimer's disease. Clinically, these results suggest that genotyping can provide information about the risk of future cognitive decline for PD patients.

Difficulty processing temporary syntactic ambiguities in Lewy body spectrum disorder

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.

The relation between depression and parkin genotype: the CORE-PD study

BACKGROUND

Mutations in parkin are a known genetic risk factor for early onset Parkinson's disease (EOPD) but their role in non-motor manifestations is not well established. Genetic factors for depression are similarly not well characterized. We investigate the role of parkin mutations in depression among those with EOPD and their relatives.

METHODS

We collected psychiatric information using the Patient Health Questionnaire and Beck Depression Inventory II on 328 genotyped individuals including 88 probands with early onset PD (41 with parkin mutations, 47 without) and 240 first and second-degree relatives without PD.

RESULTS

Genotype was not associated with depression risk among probands. Among unaffected relatives of EOPD cases, only compound heterozygotes (n = 4), and not heterozygotes, had significantly increased risk of depressed mood (OR = 14.1; 95% CI 1.2-163.4), moderate to severe depression (OR = 17.8; 95% CI 1.0-332.0), depression (score ≥ 15) on the Beck Depression Inventory II (BDI-II) (OR = 51.9; 95% CI 4.1-657.4), and BDI-II total depression score (β = 8.4; 95% CI 2.4-11.3) compared to those without parkin mutations.

CONCLUSIONS

Relatives of EOPD cases with compound heterozygous mutations and without diagnosed PD may have a higher risk of depression compared to relatives without parkin mutations. These findings support evidence of a genetic contribution to depression and may extend the phenotypic spectrum of parkin mutations to include non-motor manifestations that precede the development of PD.

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.

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.

Alzheimer's disease pattern of brain atrophy predicts cognitive decline in Parkinson's disease

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.

Early retirement and income loss in patients with early and advanced Parkinson's disease

BACKGROUND

The indirect costs of Parkinson's disease (PD) may be larger than direct healthcare costs, and the largest component of indirect costs is income loss related to early retirement. No recent retrospective analysis details PD-related early retirement and income loss in the US.

OBJECTIVE

We used an observational, matched cohort to study wages and labour force participation over 4 years and to simulate lifetime income losses conditional on being newly diagnosed with PD (naive) or having evidence of increasing disability.

METHODS

Actively employed primary beneficiaries of private insurance policies aged 18-64 years with more than two PD diagnoses (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM]: 332.x) or one diagnosis and a prescription of an antiparkinsonian drug were selected from a privately insured claims database. Continuous health coverage during analysis periods was required. Naive patients were defined as having no claims history indicative of PD during the year prior to first diagnosis or prescription use. A PD with ambulatory assistance devices (PDAAD) cohort was also followed from the date of first evidence of a wheelchair or walker. Controls without PD were matched on age, sex and region. Survival analysis and Wilcoxon rank sum tests were used to compare rates of early retirement and income loss. A simulation of projected economic loss was conducted for PD cohorts diagnosed at different ages using Bureau of Labor Statistics labour force participation and income data.

RESULTS

Naive PD patients (n = 278) and PDAAD patients (n = 28) were on average aged 53 years and had significantly higher rates of co-morbidities at baseline versus controls. Conditional on being employed, there was no statistical difference in earnings. However, the hazard of early retirement associated with PD was 2.08 (p < 0.001) for the naive cohort and 5.01 (p < 0.001) for the PDAAD cohort. From age 40 to 79 years, earnings losses in year 2009 values were $US569 393, $US188 590, $US35 496 and $US2451 for those diagnosed at age 45, 55, 65 and 75 years, respectively. Estimates increased by 9% to 37% when using expected 2018 labour force participation estimates.

CONCLUSIONS

The cost of early retirement associated with patients with PD was substantial. Given that the proportion of Americans participating in the labour force in older age groups is expected to increase, PD-related early retirement costs will likely rise.

The organization of narrative discourse in Lewy body spectrum disorder

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.

Screening questionnaires for parkinsonism: a systematic review

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 to 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.