REM sleep without atonia and nocturnal body position in prediagnostic Parkinson's disease

BackgroundSleep disturbances are features of Parkinson's disease (PD), that can already occur before PD diagnosis. The most investigated prodromal PD sleep disorder is REM sleep behavior disorder (RBD). The relation between other polysomnographic (PSG) alterations and the prediagnostic stages of PD, however, is less clear.MethodsWe performed a retrospective case–control study to characterize polysomnographic alterations in PD and prediagnostic PD. We included 63 PD subjects (33 subjects that underwent a video-PSG before PD diagnosis [13 with and 20 without RBD] and 30 subjects that underwent a PSG after PD diagnosis) and 30 controls. PSGs were analyzed for sleep stages, different RSWA variables, body position, arousals, periodic limb movements, and REM density.ResultsHigher subscores of all RSWA variables were observed in subjects with PD and prediagnostic PD (with and without RBD). Total RSWA, tonic RSWA and chin RSWA severity were significant predictors for all PD and prediagnostic PD groups. Our study also shows a higher percentage of nocturnal supine body position in all PD and prediagnostic PD groups. Supine body position percentage is the highest in the PD group and has a positive correlation with time since diagnosis.ConclusionsThese findings suggest that increased total, tonic and chin RSWA as well as nocturnal supine body position are already present in prediagnostic PD, independently of RBD status. Prospective longitudinal studies are necessary to confirm the additional value of these PSG abnormalities as prodromal PD biomarkers.     

Parkinson's disease‐cognitive rating scale: Psychometrics for mild cognitive impairment

Lack of validated data on cutoff scores for mild cognitive impairment (MCI) and sensitivity to change in predementia stages of Parkinson's disease (PD) limit the utility of instruments measuring global cognition as screening and outcome measures in therapeutic trials. Investigators who were blinded to PD‐Cognitive Rating Scale (PD‐CRS) scores classified a cohort of prospectively recruited, nondemented patients into a PD with normal cognition (PD‐NC) group and a PD with MCI (PD‐MCI) group using Clinical Dementia Rating (CDR) and the Mattis Dementia Rating Scale‐2 (MDRS‐2). The discriminative power of the PD‐CRS for PD‐MCI was examined in a representative sample of 234 patients (145 in the PD‐NC group; 89 in the PD‐MCI group) and in a control group of 98 healthy individuals. Sensitivity to change in the PD‐CRS score (the minimal clinically important difference was examined with the Clinical Global Impression of Change scale and was calculated with a combination of distribution‐based and anchor‐based approaches) was explored in a 6‐month observational multicenter trial involving a subset of 120 patients (PD‐NC, 63; PD‐MCI, 57). Regression analysis demonstrated that PD‐CRS total scores (P < 0.001) and age (P = 0.01) independently differentiated PD‐NC from PD‐MCI. Area under the receiver operating characteristic curve (AUC) analysis (AUC, 0.85; 95% confidence interval, 0.80–0.90) indicated that a score ≤81 of 134 was the optimal cutoff point on the total score for the PD‐CRS (sensitivity, 79%; specificity, 80%; positive predictive value, 59%; negative predictive value, 91%). A range of change from 10 to 13 points on the PD‐CRS total score was indicative of clinically significant change. These findings suggest that the PD‐CRS is a useful tool to identify PD‐MCI and to track cognitive changes in nondemented patients with PD. © 2013 International Parkinson and Movement Disorder Society     

Executive dysfunction in non-demented Parkinson's disease patients with hallucinations

Objective –  We investigated executive function in Parkinson's disease (PD) patients, and focused on executive dysfunction in PD with hallucinations, but without dementia.
Methods –  PD patients were classified by cognitive or neuropsychotic status as PD group, PD with vivid dreaming group, PD with hallucinations group and Parkinson's disease dementia (PDD) group. Psychomotor speed tests, the Stroop test, a verbal fluency test and the Self-rating Depression Scale were performed.
Results –  The PDD group showed poorer scores in every test compared with the PD group. The PD with hallucinations group showed results similar to those of the PDD group, while the PD with vivid dreaming group was similar to the PD group.
Conclusions –  The study suggests that PD patients with hallucinations, not extensive enough to qualify as dementia, already have executive dysfunction similar to that seen in PDD patients. Executive dysfunction may be an important substrate for hallucinations even when dementia is not yet apparent.     

A family history of Parkinson's disease and its effect on other PD risk factors.

Parkinson's disease (PD) is likely a result of both inherited and exogenous factors. In a study of 144 PD cases and 464 controls, we used PD family history as a surrogate for inherited PD susceptibility. Cases were more likely to report a first- or second-degree relative with PD: 16.0 vs. 4.3%; odds ratio (OR) = 4. 2; 95% confidence interval (CI) = 2.3-7.6. A PD family history was a greater risk factor for PD in subjects under age 70 (OR = 8.8; 95% CI = 3.4-22.8) compared with those over 70 (OR = 2.8; 95% CI = 1.3-6. 1) and in men (OR = 8.1; 95% CI = 3.4-19.2) compared with women (OR = 2.6; 95% CI = 1.1-6.0). We also tested whether a PD family history modified the effects of other PD risk factors. In subjects with a PD family history, occupational exposure to copper, lead or iron increased the risk for PD (OR = 3.0; 95% CI = 0.7-13.3), but this was not the case for those without a family history (OR = 1.1; 95% CI = 0.7-1.6). Ever smoking cigarettes was inversely associated with PD in those without a PD family history (OR = 0.6; 95% CI = 0.4-0.9), but was positively associated with PD in those with a PD family history (OR = 1.7; 95% CI = 0.5-5.9). In summary, our results suggest that a PD family history, and perhaps, therefore, an inherited susceptibility, confers a greater risk for PD in men and individuals under 70 years of age and may modify the effects of environmental risk factors for PD.     

Enhanced cued recall and clock drawing test performances differ in Parkinson's and Alzheimer's disease-related cognitive dysfunction

Cognitive impairment either as dementia (PD–D) or mild cognitive impairment (PD–MCI) is common in Parkinson's disease (PD). The clinical features and cognitive profile differs from Alzheimer's disease (AD) or amnestic MCI (aMCI). In this study we aim to disclose the utility of pre-selected practical neuropsychological tests in differentiation of PD–D and AD, and also PD–MCI and aMCI. Consecutive cases with mild to moderate AD (n = 32) and PD–D (n = 26); aMCI (n = 34) and PD–MCI (n = 19) were evaluated. Although MMSE scores were similar in PD–D and AD or in PD–MCI and aMCI groups, memory impairment assessed by enhanced cued recall (ECR) was more apparent in AD than PD–D; and ECR scores tended to be worse in aMCI group than PD–MCI group. In contrast, clock drawing was more impaired in PD–D than AD. For differentiation of PD–D from AD, ECR, clock drawing and letter fluency were found to be valuable with moderately high sensitivity and specificities. In differentiation of aMCI and PD–MCI, ECR, clock drawing test and copying of intersecting pentagons were helpful. Stepwise linear discrimination function analysis disclosed that combination of ECR and clock drawing tests correctly classified 70.7% of the overall study population (71.4% of AD, 71.9% of aMCI, 69.6% of PD–D and 68.8% of PD–MCI). These findings suggest that ECR and clock drawing tests can be valuable as an additive to clinical diagnostic criteria in differentiation of PD–D and PD–MCI cases from AD and aMCI.     

Subjectively impaired bed mobility in Parkinson disease affects sleep efficiency

BackgroundImpaired bed mobility (IBM) may be an important reason for the high prevalence of sleep insomnia in Parkinson disease (PD). Here we assessed the influence of subjectively IBM on both subjective and objective sleep parameters in insomnia PD patients with (PD+IBM) and without (PD−IBM) concerns of IBM and controls with primary insomnia.MethodsWe included 44 PD patients with sleep initiation or maintenance concerns and 44 control subjects with primary insomnia. Sleep questionnaires, polysomnographic sleep parameters, activity data, and the number of body position changes were compared between PD patients and controls as well as within the PD group between PD+IBM vs PD−IBM subjects.ResultsThere were 54.5% of PD subjects who reported having IBM. In the PD+IBM group, the number of body position changes was significantly lower than in PD−IBM (0.4/h [0.0–1.8] vs 1.4/h [0.0–4.6], P = .015). Sleep efficiency (SE) was lower in PD+IBM patients (63.5; 26.2–85.6) compared to PD−IBM patients (78.4; 54.8–92.6; P < .001).ConclusionPD patients who report IBM have fewer sleep-related body position changes (i.e., nocturnal hypokinesia) than PD patients without such concerns. Furthermore, objective SE is significantly diminished in these patients.     

Olfactory performance and resting state functional connectivity in non‐demented drug naïve patients with Parkinson's disease

Olfactory performance in Parkinson's disease (PD) is closely associated with subsequent cognitive decline. In the present study, we analyzed the olfaction‐dependent functional connectivity with a hypothesis that olfactory performance would influence functional connectivity within key brain areas of PD. A total of 110 nondemented drug‐naïve patients with PD were subdivided into three groups of high score (PD‐H, n = 23), middle score (PD‐M, n = 64), and low score (PD‐L, n = 23) based on olfactory performance. We performed the resting‐state functional connectivity with seed region of interest in the posterior cingulate cortex (PCC) and caudate. An analysis of functional connectivity revealed that PD‐L patients exhibited a significant attenuation of cortical functional connectivity with the PCC in the bilateral primary sensory areas, right frontal areas, and right parietal areas compared to PD‐H or PD‐M patients. Meanwhile, PD‐L patients exhibited a significant enhancement of striatocortical functional connectivity in the bilateral occipital areas and right frontal areas compared to PD‐H or PD‐M patients. In the voxel‐wise correlation analysis, olfactory performance was positively associated with cortical functional connectivity with the PCC in similar areas of attenuated cortical connectivity in PD‐L patients relative to PD‐H patients. On the other hand, the cortical functional connectivity with the caudate was negatively correlated with olfactory performance in similar areas of increased connectivity in PD‐L patients relative to PD‐H patients. The present study demonstrated that resting state functional connectivity exhibits a distinctive pattern depending on olfactory performance, which might shed light on a meaningful relationship between olfactory impairment and cognitive dysfunction in PD. Hum Brain Mapp 36:1716–1727, 2015. © 2014 Wiley Periodicals, Inc.     

Cancer in Parkinson’s disease

INTRODUCTIONWe examined the prevalence of cancer in patients with Parkinson’s disease (PD) and controls evaluated at the Mayo Clinic in Jacksonville, Florida, between 2003 and 2014.METHODSWe retrospectively collected information regarding cancer diagnoses and diagnosis of PD from 971 unrelated PD patients and 478 controls, and all were white. For PD patients, we examined cancers diagnosed before and after PD diagnosis separately in addition to considering all cancer diagnoses.RESULTSTwenty different cancers were identified. In PD patients, the most common types of cancer were skin cancer (17.3% overall; 10.6% before PD), followed by nonmelanoma skin cancer (16.0% overall; 9.7% before PD), prostate cancer in men (12.8% overall; 9.2% before PD), breast cancer in women (10.6% overall; 6.3% before PD), and melanoma (2.4% overall; 1.1% before PD). Compared to controls, a significantly lower frequency of nonmelanoma skin cancer (odds ratio [OR]: 0.62, P = 0.0024) and any skin cancer (OR: 0.57, P = 0.0002) was observed in PD patients. These differences were greater when considering only cases with cancers that occurred before PD diagnosis (OR: 0.49, P < 0.0001; OR: 0.45, P < 0.0001, respectively), and there was a lower frequency of melanoma and any cancer preceding PD diagnosis compared to controls (OR: 0.31, P = 0.003; OR: 0.36, P < 0.0001). There was no evidence of a frequency difference for any other cancer.CONCLUSIONSPD patients had a lower frequency of skin cancers or any cancer prior to PD diagnosis compared to controls, suggesting that cancer may have a protective effect on PD risk.     

Impaired motor cortical facilitatory-inhibitory circuit interaction in Parkinson’s disease

ObjectiveMotor cortical (M1) inhibition and facilitation can be studied with short-interval intracortical inhibition (SICI) and short-interval intracortical facilitation (SICF). These circuits are altered in Parkinson’s disease (PD). The sensorimotor measure short latency afferent inhibition (SAI) is possibly altered in PD. The aim was to determine if the manner in which these circuits interact with each other is abnormal in PD.MethodsFifteen PD patients were studied at rest in ON and OFF medication states, and were compared to 16 age-matched controls. A triple-stimulus transcranial magnetic stimulation paradigm was used to elicit a circuit of interest in the presence of another circuit.ResultsSICF was increased in PD OFF and PD ON conditions compared to controls. SICI facilitated SICF in controls and PD ON, but not in PD OFF. SICF in the presence of SICI negatively correlated with UPDRS-III scores in OFF and ON medication conditions. SAI showed similar inhibition of SICI in controls, PD OFF and PD ON conditions.ConclusionsThe facilitatory effect of SICI on SICF is absent in PD OFF, but is restored with dopaminergic medication.SignificanceImpaired interaction between M1 circuits is a pathophysiological feature of PD.     

Peripheral insulin and amylin levels in Parkinson's disease

BackgroundType-2-diabetes (T2D) has surfaced as a potential risk factor for Parkinson's disease (PD) in some epidemiological studies. Evidence of glucose metabolism alterations in PD from molecular studies remains conflicting. Amylin, the T2D amyloid protein, has been implicated in PD in pathological studies. We aimed to assess peripheral levels of amylin and insulin in PD patients and control subjects (Cs).MethodsWe conducted an observational cross-sectional study of 111 participants: 73 PD and 38 Cs, similar in age, sex and body mass index. All underwent motor (UPDRS-MDS-III), non-motor (NMSS) and cognitive (MDRS) scales as well as determination of four parameters: fasting glycaemia, glycated haemoglobin, fasting plasma insulin (FPI) and fasting plasma amylin (FPA).ResultsFPI was significantly lower in PD than Cs (p = 0.034). In participants with age above cohort-median-age, FPA was higher in PD than Cs (p = 0.046). The FPA/FPI ratio (FPAIR) was significantly higher in PD than Cs (p = 0.024). In PD, modest correlation was found between higher insulin-resistance and NMSS scores.ConclusionsPD patients had lower FPI and increased FPAIR. In older PD subgroup, FPA was increased. The more the insulin resistance, the higher the non-motor scores. These findings provide an additional link between pathophysiology of diabetes and PD. This might be related to a dissociated insulin and amylin secretion in PD, in line with recent evidence of endocrine pancreas role in PD pathogeny.     

Defining mild cognitive impairment in Parkinson's disease

Our purpose was to characterize a state of mild cognitive impairment (MCI) in Parkinson's disease (PD) (PD‐MCI) that would be analogous to the MCI that is posited as a precursor of Alzheimer's disease (AD). We categorized 86 PD subjects in a brain bank population as either cognitively normal (PD‐CogNL), PD‐MCI using criteria that included a 1.5 standard deviation or greater deficit upon neuropsychological testing consistently across at least one cognitive domain without dementia, and PD dementia (PD‐D) using DSM‐IV criteria. Twenty‐one percent of our PD sample met criteria for PD‐MCI, 62% were PD‐CogNL, and 17% had PD‐D. The mean duration of PD and MMSE scores of the PD‐MCI group were intermediate and significantly different from both PD‐CogNL and PD‐D. The cognitive domain most frequently abnormal in PD‐MCI was frontal/executive dysfunction followed by amnestic deficit. Single domain PD‐MCI was more common than PD‐MCI involving multiple domains. We conclude that a stage of clinical cognitive impairment in PD exists between PD‐CogNL and PD‐D, and it may be defined by applying criteria similar to the MCI that is posited as a precursor of AD. Defining PD‐MCI offers an opportunity for further study of cognitive impairment in PD and targets for earlier therapeutic intervention. © 2007 Movement Disorder Society     

Diabetes preceding Parkinson's disease onset. A case–control study

ObjectiveTo assess the association between diabetes preceding Parkinson's disease (PD) and PD.MethodsPD individuals were matched to PD free individuals randomly selected from people in the same municipality as the cases. Occurrence of diabetes preceding PD onset among cases and controls was assessed through a structured questionnaire. Information regarding current and past medical treatment and other variables was also collected. We used univariate and multivariate logistic models to calculate crude and adjusted odds ratios (OR). Covariates are adjusted for included education, smoking habit, alcohol and coffee consumption.Results318 PD individuals (165 women, 153 men) and 318 matched controls were included in the study. PD patients had a mean age at interview of 66.7 years. Mean age at PD onset was 60.8 years and mean PD duration 5.9 years. We found an inverse association between PD and diabetes preceding PD onset in all groups stratified by gender, age at PD onset, body mass index (BMI), smoking habit, alcohol and coffee consumption. Multivariate analysis yielded the same findings after controlling for the variables (adjusted OR 0.4; 95% CI, 0.2–0.8).ConclusionsOur findings provide additional support for a potential link between diabetes and PD.     

Transcranial brain sonography in Parkinson's disease with restless legs syndrome

Substantia nigra (SN) hyperechogenicity assessed by transcranial brain sonography (TCS) is a characteristic finding in idiopathic Parkinson's disease (PD). In contrast, SN hypoechogenicity on TCS has been recently demonstrated in restless legs syndrome (RLS). RLS is one of the most common sleep problems in PD, but the pathophysiologic relationship between these two disorders has not been thoroughly elucidated. We compared the SN echogenicities of PD patients with and without RLS to investigate whether comorbid RLS in PD affects SN echogenicity and to explain the echogenic differences between idiopathic RLS (iRLS) and secondary PD–related RLS (pRLS). Sixty‐three PD patients (median age 64.6 ± 10.6 years), 40 iRLS patients (53.1 ± 11.7 years), and 40 healthy controls (69.1 ± 2.3 years) were enrolled in our study. All subjects answered a sleep questionnaire and underwent TCS. PD patients were subdivided into two groups, PD with RLS (PD+RLS, n = 26) and PD without RLS (PD‐RLS, n = 37), and the sonographic findings of each group were compared. Although significant hyperechogenicity was detected in both the SN and SN/midbrain ratios in both PD subgroups compared with the controls and the iRLS group (P < 0.001), there were no significant differences in SN echogenicity between the PD+RLS and PD‐RLS groups. Meanwhile, iRLS patients showed significant SN hypoechogenicity. In conclusion, comorbid RLS in PD did not have an impact on the sonographic SN findings. These results suggest that the pathogenesis of pRLS and iRLS involve different mechanisms. Further study will be required to clarify the association between RLS and PD. © 2010 Movement Disorder Society     

Depressive illness in Parkinson’s disease – indication of a more advanced and widespread neurodegenerative process?

Objective –  The aims were to study if the type and complexity of Parkinsonian symptoms, as well as treatment, could be related to the occurrence and severity of later depressive symptoms. Furthermore, the aim was to study if there is a different depressive symptomatology in Parkinson's disease (PD) patients compared with depressive illness in an age-matched group of patients with major depression but without Parkinson's disease.
Methods –  Eleven PD-patients with major depression (MD) were compared to 14 PD-patients without depression and to 12 MD patients without PD.
Results –  PD patients who later developed a depressive illness were younger at the debut of PD than patients without depression ( P < 0.05). At inclusion the depressed PD patients were more disabled than PD patients without depression with higher level in the H&Y scale ( P <0.05), and they had more involuntary movements according to Unified Parkinson's Disease Rating Scale (UPDRS IV) ( P < 0.01). A family history of depression was found in one third of the depressed non-parkinsonian patients but in none of the PD groups. Sleep disturbances were significantly more common among depressed PD patients than in PD patients without depression but even more common in depressed patients without PD.
Conclusions –  Depressed PD patients had a longer duration of PD and more severe motor symptoms than PD patients without depression, although tremor as an initial symptom seemed to be more common in PD without a later depression. It cannot be excluded that depression in PD reflects a more advanced and widespread neurodegeneration, including serotonergic as well as dopaminergic neurons. Sleep disturbances is common and could be overlooked as an expression of depression.     

Chronic pain in Parkinson's disease: The cross‐sectional French DoPaMiP survey

Pain is a frequent, but poorly studied symptom of Parkinson's disease (PD). DoPaMiP survey aimed to assess the prevalence of chronic pain in PD, to describe PD patients with chronic pain, and to record analgesic consumption. About 450 parkinsonian patients underwent structured standardized clinical examination and completed self‐reported questionnaires in a cross sectional survey. Pains related or unrelated to PD were identified according to predefined criteria. About 98 patients with other chronic disorders than PD were examined to assess if pain was more frequent in PD than in this population. Two thirds parkinsonian patients (278 of 450) had chronic pain. Twenty‐five patients with non‐chronic pain (<3‐month duration) were excluded from subsequent analysis. Twenty six percent (111 of 425) parkinsonian patients had pain unrelated to PD (“non‐PD‐pain”, caused mainly by osteoarthritis), while 39.3% (167 of 425) had chronic pain related to PD (“PD‐pain”). In this last group, PD was the sole cause of pain in 103 and indirectly aggravated pain of another origin (mainly osteoarthritis) in 64. Parkinsonian patients with “PD‐pain” were younger at PD onset, had more motor complications, more severe depressive symptoms than those without pain or with “non‐PD pain.” “PD‐pain” was more intense (P = 0.03), but was less frequently reported to doctors (P = 0.02), and was associated with less frequent analgesic consumption than “non‐PD‐pain.” Pain was twice more frequent in PD patients than in patients without PD after adjustment for osteo‐articular comorbidities (OR = 1.9; 95% CI 1.2–3.2). Chronic pain is frequent but underreported in PD. Awareness of this problem should be increased and the assessment of analgesic strategies improved. © 2008 Movement Disorder Society     

Temperament and personality features in panic disorder with or without comorbid mood disorders

Personality and temperament features, assessed with the Structured Interview for DSM-III-R Personality Disorders — Revised (SIDP-R) and the Tridimensional Personality Questionnaire (TPQ), respectively, were evaluated in 62 patients affected by panic disorder with (PD+MD) (n= 22) or without comorbid mood disorder (PD) (n=40). A significant difference in the prevalence of personality disorders (PD+MD, 86% vs. PD, 62%; P <0.05), particularly dependent (PD+DM, 50% vs. PD, 17%; P < 0.01) and borderline (PD+DM, 9% vs. PD, 0%; P=0.05) personality disorders, was observed between the groups. Moreover, patients in the PD+MD group had higher scores for harm avoidance (PD+MD, 22.2±5.6 vs. PD, 26.9±5.1; P < 0.05) than patients in the PD group. The harm avoidance score in PD patients was significantly related to personality disorder and not to MD, suggesting that harm avoidance is not associated with greater severity of the illness. Our data confirm the hypothesis that subjects with higher harm avoidance scores have a greater probability of being affected by cluster C personality disorders and comorbid mood and anxiety disorders.     

Nonmotor symptoms more closely related to Parkinson's disease: Comparison with normal elderly

Nonmotor symptoms (NMSs) commonly occur in Parkinson's disease (PD). This study sought to explore the domains of NMSs that are more closely related to PD using nonmotor symptoms scale (NMSS), through a quantitative comparison of NMSs' prevalence and NMSS scores of PD patients with normal controls, and clinical implications. We performed a prospective case–control study on PD patients (n = 131) and age- and gender-matched normal controls (n = 129). We compared NMSs' prevalence and NMSS scores of the PD patients with those of normal controls, and obtained the ratio to identify the domains that were more closely related to PD than normal aging using the NMSS. NMSs are very common among normal elderly as well as PD patients. The domains with the highest ratio of NMSs' prevalence and NMSS scores between the patient and control groups were the miscellaneous, perceptual problems/hallucinations, and sexual function. These three domains were found to be most closely related to PD. NMSs with higher prevalence in PD patients do not always relate more to PD. As NMSs in PD can also commonly occur among the normal elderly, the NMS prevalence should be interpreted with extreme caution. To properly manage the NMSs in PD, it should be kept in mind that avoiding the overestimation of NMSs as part of PD is as important as their early recognition in PD.     

Survival of Parkinson's disease patients in a large prospective cohort of male health professionals.

Parkinson's disease (PD) patients have higher mortality than individuals without PD. However, most of the previous studies were based on prevalent cases and few examined the potential effects of duration and smoking on the survival of PD patients. We compared the survival experience of 288 men with incident PD diagnosed between 1986 and 2000 with that of 51,012 men free of PD in the Health Professionals Follow-up Study. As of January 2002, 92 deaths occurred among PD cases and 8,485 among men without PD. After controlling for age, men with PD had 60% higher mortality than those without PD (95% CI: 1.3-2.0). PD mortality was strongly related to disease duration: compared with men without PD, the age-adjusted relative risk for PD patients was 1.1 during the first 5 years from diagnosis, 2.3 from 5 to 10 years, and 3.5 after 10 years (P < 0.0001 for trend). As expected, cigarette smoking was strongly and positively associated with total mortality among men free of PD (comparing >30 pack-years vs. never smokers, relative risk, 2.0; P < 0.0001 for trend), but this association was not observed among PD patients (RR: 1.0; P = 0.95 for trend). This study confirms that PD patients have a higher mortality than individuals without PD and that the excess mortality increases with disease duration. However, smoking seems to impose little additional risk among PD patients in this large cohort of health professionals.     

CSF Aβ42 and tau in Parkinson's disease with cognitive impairment

We tested the hypothesis that the CSF biomarker signature associated with Alzheimer's disease (AD) is present in a subset of individuals with Parkinson's disease and Dementia (PD‐D) or with PD and Cognitive Impairment, Not Dementia (PD‐CIND). We quantified CSF Aβ₄₂, total tau (T‐tau), and phospho‐tau (P181‐tau) using commercially available kits. Samples were from 345 individuals in seven groups (n): Controls ≤50 years (35), Controls >50 years (115), amnestic Mild Cognitive Impairment (aMCI) (24), AD (49), PD (49), PD‐CIND (62), and PD‐D (11). We observed expected changes in AD or aMCI compared with age‐matched or younger controls. CSF Aβ₄₂ was reduced in PD‐CIND (P < 0.05) and PD‐D (P < 0.01), whereas average CSF T‐tau and P181‐tau were unchanged or decreased. One‐third of PD‐CIND and one‐half of PD‐D patients had the biomarker signature of AD. Abnormal metabolism of Aβ₄₂ may be a common feature of PD‐CIND and PD‐D. © 2010 Movement Disorder Society