Cognition and the course of prodromal Parkinson's disease.

BACKGROUND: Prospective data on cognition in prodromal Parkinson's disease are limited. The objectives of this study were to assess in prodromal PD (1) if baseline cognition predicts conversion to clinical PD, (2) if baseline dopamine transporter binding predicts longitudinal changes in cognition, and (3) if impaired olfaction predicts future cognitive decline. METHODS: Prodromal participants were 136 hyposmic individuals enrolled in the Parkinson Associated Risk Study. We examined baseline neuropsychological test performance in PD converters versus nonconverters and the association between baseline dopamine transporter binding and change in cognition. An additional 73 normosmic individuals were included in analyses of the relationship between hyposmia and cognitive decline. RESULTS: In prodromal participants, baseline cognitive scores did not significantly predict conversion, but converters performed numerically worse on 5 of the 6 cognitive domains assessed, with the greatest differences in executive function/working memory (0.68 standard deviation lower) and global cognition (0.64 standard deviation lower). Lower baseline dopamine transporter binding predicted greater future decline in processing speed/attention (P = 0.02). Hyposmia predicted greater future decline in language (P = 0.005) and memory (P = 0.01) abilities. CONCLUSIONS: Given hyposmia in the general population predicts cognitive decline, the role of cognition in predicting conversion in prodromal PD needs to be assessed in large cohorts followed long-term. The dopamine system may be associated with changes in processing speed/attention in individuals at risk for PD. © 2017 International Parkinson and Movement Disorder Society.

Differential effects of deep brain stimulation target on motor subtypes in Parkinson's disease.

OBJECTIVE: The Veterans Administration Cooperative Studies Program #468, a multicenter study that randomized Parkinson's disease (PD) patients to either subthalamic nucleus (STN) or globus pallidus internus (GPi) deep brain stimulation (DBS), found that stimulation at either target provided similar overall motoric benefits. We conducted an additional analysis of this data set to evaluate whether PD motor subtypes responded differently to the 2 stimulation targets. METHODS: We classified 235 subjects by motor subtype: tremor dominant (TD), intermediate (I), or postural instability gait difficulty (PIGD), based on pre-DBS baseline Unified Parkinson's Disease Rating Scale (UPDRS) scores off-medication. The primary outcome was change in UPDRS part III (UPDRS-III) off-medication scores from baseline to 24 months post-DBS, compared among subjects with particular PD motor subtypes and by DBS target (STN vs GPi). Changes in tremor, rigidity, akinesia, and gait scores were also assessed using the UPDRS. RESULTS: TD patients had greater mean overall motor improvement, measured by UPDRS-III, after GPi DBS, compared to STN DBS (17.5 ± 13.0 vs 14.6 ± 14.9, p = 0.02), with improvement in gait accounting for this difference. Regardless of stimulation target, PIGD subjects had lower mean overall improvement in UPDRS-III scores compared with I or TD subjects (8.7 ± 12.2 vs 21.7 ± 11.2 vs 16.3 ± 13.8, p = 0.001). INTERPRETATION: Our results suggest that responsiveness to both GPi and STN DBS is similar among different PD motor subtypes, although the TD motor subtype may have a greater response to GPi DBS with respect to gait. PIGD patients obtained less overall benefit from stimulation.

Cognition in individuals at risk for Parkinson's: Parkinson associated risk syndrome (PARS) study findings.

OBJECTIVES: The Parkinson Associated Risk Syndrome Study identified a cohort of healthy adults with hyposmia and dopamine transporter binding reduction to characterize individuals at risk for Parkinson's disease (PD). We describe the cognitive profile of this cohort. METHODS: Individuals older than 50 y without PD were recruited. Two hundred twenty-five completed cognitive testing and were included in the final analysis. A neuropsychological test battery was administered and normative scores created for global cognition, memory, executive function/working memory, processing speed/attention, visuospatial abilities, and language domains. Other non-motor symptoms (constipation, depression, anxiety, and rapid eye movement sleep behavior disorder) were assessed through questionnaires. RESULTS: Individuals with both hyposmia and reduced dopamine transporter binding (n = 38) had lower mean scores for global cognition, executive function/working memory, and memory compared with all other participants (n = 187). In separate multivariate logistic regression models, lower global cognition (odds ratio, 1.97, P = 0.004), and specifically executive function/working memory (odds ratio, 1.84, P = 0.004) scores were associated with membership in the hyposmia with dopamine transporter reduction group. Combining hyposmia with relative impairment on specific cognitive domains increased the odds of dopamine transporter binding reduction compared with hyposmia alone, with the greatest increase in odds for hyposmia plus executive function/working memory relative impairment (68% increase in odds from 4.14 to 6.96). CONCLUSION: Changes in global cognitive abilities, and specifically executive function/working memory, are present in individuals at risk for PD. Combining non-motor features, including cognition, improves prediction of dopamine transporter binding reduction.

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.

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.

Diagnostic markers for Parkinson's disease.

PURPOSE OF REVIEW: This review enumerates recent developments in the early diagnosis of Parkinson's disease, with an emphasis on detection of preclinical Parkinson's disease. RECENT FINDINGS: Several clinical, laboratory, and imaging tests are now being investigated as potential early markers of Parkinson's disease. These include various nonmotor features that predate the motor manifestations of Parkinson's disease, including sleep abnormalities, neurobehavioral symptoms, and olfactory dysfunction. Tests of the autonomic nervous system, such as cardiac functional imaging, allow for a measure of cardiac sympathetic denervation. Cerebrospinal fluid and serum tests, including α-synuclein and DJ-1, are being developed and refined. Various imaging modalities have contributed to the diagnostic armamentarium in Parkinson's disease, including transcranial Doppler ultrasonography, radiolabeled tracer imaging, and magnetic resonance imaging. Early Parkinson's disease detection will pave the way for major advances in disease modifying therapies. SUMMARY: Various diagnostic modalities hold promise for the early and preclinical diagnosis of Parkinson's disease. It is likely that the future diagnosis of Parkinson's disease will rely on a combination of clinical, laboratory, imaging, and genetic data.

Parkinson's at risk syndrome: can Parkinson's disease be predicted?

The treatment of Parkinson's disease (PD) has revolved around pharmacologic interventions that primarily treat the cardinal (dopaminergic) manifestations of tremor, rigidity, and bradykinesia; yet, we now know that the pathology of PD is widespread, accounting for more disabling symptoms such as cognitive impairment, autonomic problems, and postural instability. Further, attempts at modifying PD may be hampered as much by the imperfection of therapeutic interventions as by the extent of neuronal damage that exists even in early PD, when most putative neuroprotective agents are tried. Our approach to PD must therefore evolve and include strategies for detecting PD earlier in its course and, eventually, intervening when the disease process is in its nascent stages. Parkinson's associated risk syndrome (PARS) is the term we have coined to describe patients at risk for developing PD. These patients may have genetic risk factors or may have subtle, early non-motor symptoms including abnormalities in olfaction, gastrointestinal function, cardiac imaging, vision, behavior, and cognition. Changes in neuroimaging modalities can predict the emergence of neurologic signs and symptoms within several years. The PARS study is now underway to determine the feasibility of screening a large cohort of subjects to identify those at highest risk for developing PD. If successful, we will have the tools to identify cohorts for clinical trials of PD prevention or, at the very least, delay of disease onset, and long-term disability. Further, our concept of PD risk will change the nosology of PD as those now considered "at-risk" may ultimately be considered to already have the disease.

Decreased ventral striatal activity with impulse control disorders in Parkinson's disease.

A range of impulse control disorders (ICDs) are reported to occur in Parkinson's disease (PD). However, alterations in brain activity at rest and during risk taking occurring with ICDs in PD are not well understood. We used both arterial spin labeling perfusion functional magnetic resonance imaging (fMRI) to directly quantify resting cerebral blood flow (CBF) and blood oxygenation level dependent (BOLD) fMRI to measure neural responses to risk taking during performance on the Balloon Analogue Risk Task (BART). Eighteen PD patients, either with a diagnosis of one or more ICDs (N = 9) or no lifetime ICD history (N = 9), participated. BOLD fMRI data demonstrated that PD patients without an ICD activate the mesocorticolimbic pathway during risk taking. Compared with non-ICD patients, ICD patients demonstrated significantly diminished BOLD activity in the right ventral striatum during risk taking and significantly reduced resting CBF in the right ventral striatum. ICDs in PD are associated with reduced right ventral striatal activity at rest and diminished striatal activation during risk taking, suggesting that a common neural mechanism may underlie ICDs in individuals with PD and those without PD. Thus, treatments for ICDs in non-PD patients warrant consideration in PD patients with ICDs.

Health-related quality of life in Parkinson disease: correlation between Health Utilities Index III and Unified Parkinson's Disease Rating Scale (UPDRS) in U.S. male veterans.

OBJECTIVE: To apply a scaled, preference-based measure to the evaluation of health-related quality of life (HRQoL) in Parkinson's disease (PD); to evaluate the relationship between disease-specific rating scales and estimated HRQoL; and to identify predictors of diminished HRQoL. BACKGROUND: Scaled, preference-based measures of HRQoL ("utilities") serve as indices of impact of disease, and can be used to generate quality-adjusted estimates of survival for health-economic evaluations. Evaluation of utilities for PD and their correlation with standard rating scales have been limited. METHODS: Utilities were generated using the Health Utilities Index Mark III (HUI-III) on consecutive patients attending a PD Clinic between October 2003 and June 2006. Disease severity, medical, surgical (subthalamic nucleus deep brain stimulation (STN-DBS)), and demographic information were used as model covariates. Predictors of HUI-III utility scores were evaluated using the Wilxocon rank-sum test and linear regression models. RESULTS: 68 men with a diagnosis of PD and a mean age of 74.0 (SD 7.4) were included in the data analysis. Mean HUI-III utility at first visit was 0.45 (SD 0.33). In multivariable models, UPDRS-II score (r2 = 0.56, P < 0.001) was highly predictive of HRQoL. UPDRS-III was a weaker, but still significant, predictor of utility scores, even after adjustment for UPDRS-II (P = 0.01). CONCLUSIONS: Poor self-care in PD reflected by worsening UPDRS-II scores is strongly correlated with low generic HRQoL. HUI-III-based health utilities display convergent validity with the UPDRS-II. These findings highlight the importance of measures of independence as determinants of HRQoL in PD, and will facilitate the utilization of existing UPDRS data into economic analyses of PD therapies.

Premotor Parkinson's disease: clinical features, detection, and prospects for treatment.

The period immediately before the onset of motor symptoms of Parkinson's disease (PD) often has a recognizable phenotype with features including autonomic dysfunction and impaired olfaction. Subclinical dopaminergic cell loss can also be detected at this time using molecular imaging techniques. A greater recognition of the features of premotor PD and improvements in screening technologies have opened the possibility of predictive testing for PD. In addition to molecular imaging of the dopamine system, screening tests that can potentially be used to identify the physiological abnormalities in premotor PD include olfactory testing, imaging of the sympathetic innervation of the heart, transcranial ultrasound, and genetic testing for mutations known to cause hereditary PD. All of these technologies have trade-offs as screening tests for accuracy, availability, and costs. Using these tests in combination may produce a more favorable combination of reasonable cost and accuracy than using any single test alone. Ultimately, the value of screening for PD depends on development of neuroprotective treatments for PD that would create an imperative for early identification and treatment.

Premotor Parkinson's disease: clinical features and detection strategies.

In many areas of medicine, the focus has shifted from treating existing disease to screening and prevention. The technology to screen for Parkinson's disease (PD) already exists. The current challenge is to define the appropriate use of predictive testing for PD. Imaging technologies currently offer the highest degree of accuracy for identifying premotor PD, but they are expensive as screening tools. Efficiency is greatly enhanced by combining imaging with a prescreening test, such as olfactory testing. This two-step process has the potential to greatly reduce costs while retaining diagnostic accuracy. 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. Current research to evaluate efficient screening methods and to understand the clinical and physiological features of "premotor" PD will lay the foundation for the screening and prevention strategies of the future.

Validation of the questionnaire for impulsive-compulsive disorders in Parkinson's disease.

As no comprehensive assessment instrument for impulse control disorders (ICDs) in Parkinson's disease (PD) exists, the aim of this study was to design and assess the psychometric properties of a self-administered screening questionnaire for ICDs and other compulsive behaviors in PD. The Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP) has 3 sections: Section 1 assesses four ICDs (involving gambling, sexual, buying, and eating behaviors), Section 2 other compulsive behaviors (punding, hobbyism, and walkabout), and Section 3 compulsive medication use. For validation, a convenience sample of 157 PD patients at 4 movement disorders centers first completed the QUIP, and then was administered a diagnostic interview by a trained rater blinded to the QUIP results. A shortened instrument (QUIP-S) was then explored. The discriminant validity of the QUIP was high for each disorder or behavior (receiver operating characteristic area under the curve [ROC AUC]: gambling = 0.95, sexual behavior = 0.97, buying = 0.87, eating = 0.88, punding = 0.78, hobbyism = 0.93, walkabout = 0.79). On post hoc analysis, the QUIP-S ICD section had similar properties (ROC AUC: gambling = 0.95, sexual behavior = 0.96, buying = 0.87, eating = 0.88). When disorders/behaviors were combined, the sensitivity of the QUIP and QUIP-S to detect an individual with any disorder was 96 and 94%, respectively. Scores on the QUIP appear to be valid as a self-assessment screening instrument for a range of ICDs and other compulsive behaviors that occur in PD, and a shortened version may perform as well as the full version. A positive screen should be followed by a comprehensive, clinical interview to determine the range and severity of symptoms, as well as need for clinical management.

Use of latent variable modeling to delineate psychiatric and cognitive profiles in Parkinson disease.

OBJECTIVES: A range of psychiatric symptoms and cognitive deficits occur in Parkinson disease (PD), and symptom overlap and comorbidity complicate the classification of nonmotor symptoms. The objective of this study was to use analytic-based approaches to classify psychiatric and cognitive symptoms in PD. DESIGN: Cross-sectional evaluation of a convenience sample of patients in specialty care. SETTING: Two outpatient movement disorders centers at the University of Pennsylvania and Philadelphia Veterans Affairs Medical Center. PARTICIPANTS: One hundred seventy-seven patients with mild-moderate idiopathic PD and without significant global cognitive impairment. MEASUREMENTS: Subjects were assessed with an extensive psychiatric, neuropsychological, and neurological battery. Latent class analysis (LCA) was used to statistically delineate group-level symptom profiles across measures of psychiatric and cognitive functioning. Predictors of class membership were also examined. RESULTS: Results from the LCA indicated that a four-class solution best fit the data. The 32.3% of the sample had good psychiatric and normal cognitive functioning, 17.5% had significant psychiatric comorbidity but normal cognition, 26.0% had few psychiatric symptoms but had poorer cognitive functioning across a range of cognitive domains, and 24.3% had both significant psychiatric comorbidity and poorer cognitive functioning. Age, disease severity, and medication use predicted class membership. CONCLUSIONS: LCA delineates four classes of patients in mild-moderate PD, three of which experience significant nonmotor impairments and comprise over two thirds of patients. Neuropsychiatric symptoms and cognitive deficits follow distinct patterns in PD, and further study is needed to determine whether these classes are generalizable, stable, predict function, quality of life, and long-term outcomes and are amenable to treatment at a class level.

Mild cognitive impairment is common in Parkinson's disease patients with normal Mini-Mental State Examination (MMSE) scores.

PURPOSE: Cognitive impairment occurs in the majority of Parkinson's disease (PD) patients, but little is known about detection of mild cognitive impairment (MCI) in this population. We report on the frequency and characteristics of cognitive deficits in PD patients with intact global cognition based on Mini-Mental State Examination (MMSE) performance. METHODS: One hundred and six PD patients with normal age- and education-adjusted MMSE scores (mean [SD] score=29.1 [1.1]) were administered standardized neuropsychological tests assessing memory, executive function, and attention. Impairment on a cognitive domain was a low score (i.e., >or=1.5 SD below the published normative mean) on at least two measures or tests (for memory and executive abilities) or a single measure (for attention). RESULTS: Mild cognitive impairment was found in 29.2% of PD patients, with 17.9% demonstrating single domain and 11.3% multiple domain impairment. Memory and attention impairment were most common (15.1% and 17.0%, respectively), followed by executive impairment (8.5%). Depending on the measure of disease severity chosen, increasing age and disease severity, anti-anxiety medication use, and a suggestion for increasing severity of daytime sleepiness were independent predictors of cognitive impairment. CONCLUSIONS: Cognitive deficits are common in PD patients with "normal" cognition based on MMSE performance, suggesting that MCI is under-recognized in clinical practice due to routine use of insensitive screening instruments. In contrast with some previous reports, early memory impairment may be as common as either executive or attentional deficits in PD. In addition, psychiatric medication use and daytime sleepiness may be reversible or treatable contributors to cognitive impairment.

Suicidal and death ideation in Parkinson's disease.

Parkinson's disease (PD) is a chronic, disabling illness affecting primarily the elderly and is associated with a high prevalence of depression. Although these are known risk factors for suicidal and death ideation, little is known about the prevalence and correlates of such ideation in PD. A convenience sample of 116 outpatients with idiopathic PD at two movement disorders centers were administered a modified Paykel Scale for suicidal and death ideation, as well as an extensive psychiatric, neuropsychological, and neurological battery. Univariate and multivariate logistic regression models were used to determine the correlates of suicidal or death ideation. Current death ideation (28%) or suicide ideation (11%) were present in 30% of the sample, and 4% had a lifetime suicide attempt. On univariate logistic regression analysis, increasing severity of depression (odds ratio = 2.92, 95% CI 2.01-4.24, P < 0.001), impulse control disorder (ICD) behaviors sometime during PD (odds ratio = 6.08, 95% CI 1.90-19.49, P = 0.002), and psychosis (odds ratio = 2.45, 95% CI 1.05-5.69, P = 0.04) were associated with either ideation. On multivariate logistic regression analysis, only increasing severity of depressive symptoms (odds ratio = 2.76, 95% CI 1.88-4.07, P < 0.001) predicted suicidal or death ideation. In conclusion, active suicidal or death ideation occurs in up to one-third of PD patients. Comorbid psychiatric disorders, more than PD-related disease variables, are associated with this ideation, highlighting the need for a comprehensive approach to the clinical care of PD patients.

Long-term follow-up of impulse control disorders in Parkinson's disease.

Recent studies have linked dopamine agonist (DA) usage with the development of impulse control disorders (ICDs) in Parkinson's disease (PD). Little is known about optimal management strategies or the long-term outcomes of affected patients. To report on the clinical interventions and long-term outcomes of PD patients who developed an ICD after DA initiation. Subjects contacted by telephone for a follow-up interview after a mean time period of 29.2 months. They were administered a modified Minnesota Impulse Disorder Interview for compulsive buying, gambling, and sexuality, and also self-rated changes in their ICD symptomatology. Baseline and follow-up dopamine replacement therapy use was recorded and verified by chart review. Of 18 subjects, 15 (83.3%) participated in the follow-up interview. At follow-up, patients were receiving a significantly lower DA levodopa equivalent daily dosage (LEDD) (Z = -3.1, P = 0.002) and a higher daily levodopa dosage (Z = -1.9, P = 0.05), but a similar total LEDD dosage (Z = -0.47, P = 0.64) with no changes in Unified Parkinson's Disease Rating Scale motor score (Z = -1.3, P = 0.19). As part of ICD management, 12 (80.0%) patients discontinued or significantly decreased DA treatment, all of whom experienced full or partial remission of ICD symptoms by self-report, and 10 (83.3%) of whom no longer met diagnostic criteria for an ICD. For PD patients who develop an ICD in the context of DA treatment, discontinuing or significantly decreasing DA exposure, even when offset by an increase in levodopa treatment, is associated with remission of or significant reduction in ICD behaviors without worsening in motor symptoms.

Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS): scale presentation and clinimetric testing results.

We present a clinimetric assessment of the Movement Disorder Society (MDS)-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS). The MDS-UDPRS Task Force revised and expanded the UPDRS using recommendations from a published critique. The MDS-UPDRS has four parts, namely, I: Non-motor Experiences of Daily Living; II: Motor Experiences of Daily Living; III: Motor Examination; IV: Motor Complications. Twenty questions are completed by the patient/caregiver. Item-specific instructions and an appendix of complementary additional scales are provided. Movement disorder specialists and study coordinators administered the UPDRS (55 items) and MDS-UPDRS (65 items) to 877 English speaking (78% non-Latino Caucasian) patients with Parkinson's disease from 39 sites. We compared the two scales using correlative techniques and factor analysis. The MDS-UPDRS showed high internal consistency (Cronbach's alpha = 0.79-0.93 across parts) and correlated with the original UPDRS (rho = 0.96). MDS-UPDRS across-part correlations ranged from 0.22 to 0.66. Reliable factor structures for each part were obtained (comparative fit index > 0.90 for each part), which support the use of sum scores for each part in preference to a total score of all parts. The combined clinimetric results of this study support the validity of the MDS-UPDRS for rating PD.

Attitudes regarding the etiology and treatment of depression in Parkinson's disease: a qualitative study.

Depression in Parkinson's disease (dPD) remains under recognized and under treated. As patients' beliefs may impact the reporting and treatment of depression, this study assessed the opinions of 38 dPD patients, approximately half with a self-reported poor response to antidepressant treatment, regarding the etiology and treatment of their depression using a semi-structured, audio-taped, qualitative interview. About half of the participants listed PD itself as a primary cause for their depressive symptoms, with most in this group citing psychosocial factors rather than PD-related neurobiological factors. Antidepressant therapy, psychotherapy, and self-initiated approaches were noted as preferred treatments for dPD. Many had concerns about antidepressant therapy, listing side-effects and medication dependency most frequently. About half raised concerns about psychotherapy with trust/discomfort, stigma, and transportation issues most frequently mentioned. This preliminary study suggests that many PD patients with clinically significant depressive symptoms attribute their depression to psychosocial factors and endorse nonpharmacologic treatment approaches.

Effect of age on geriatric depression scale performance in Parkinson's disease.

The purpose of this study was to compare the validity of the 15-item Geriatric Depression Scale (GDS-15) in nonelderly (<65 years), young-elderly (age, 65-75), and old-elderly (>75 years) patients with Parkinson's disease (PD). 57 nonelderly, 88 young-elderly, and 81 old-elderly PD patients were administered the GDS-15 and the Structured Clinical Interview for DSM-IV depression module. Receiver-operating characteristic (ROC) curves were plotted for GDS-15 scores against a DSM-IV diagnosis of major or minor depression. The discriminant validity of the GDS-15 was high for nonelderly, young-elderly, and old-elderly subjects (ROC area under curve = 0.92, 0.91, and 0.95, respectively), with optimal dichotomization at a cut-off of 4/5 (85% sensitivity and 84% specificity in nonelderly; 89% sensitivity and 82% specificity in young-elderly) and 5/6 (90% sensitivity and 90% specificity in old-elderly). In conclusion, the GDS-15 has comparable validity in younger and older PD patients, suggesting its appropriateness as a depression screening instrument in PD patients of all ages.