Criteria for diagnosing Parkinson's disease

Assessment of global and regional diffusion changes along white matter tracts in parkinsonian disorders by MR tractography

Purpose

The aim of the study was to determine the usefulness of diffusion tensor tractography (DTT) in parkinsonian disorders using a recently developed method for normalization of diffusion data and tract size along white matter tracts. Furthermore, the use of DTT in selected white matter tracts for differential diagnosis was assessed.

Methods

We quantified global and regional diffusion parameters in major white matter tracts in patients with multiple system atrophy (MSA), progressive nuclear palsy (PSP), idiopathic Parkinson’s disease (IPD) and healthy controls). Diffusion tensor imaging data sets with whole brain coverage were acquired at 3 T using 48 diffusion encoding directions and a voxel size of 2×2×2 mm³. DTT of the corpus callosum (CC), cingulum (CG), corticospinal tract (CST) and middle cerebellar peduncles (MCP) was performed using multiple regions of interest. Regional evaluation comprised projection of fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and the apparent area coefficient (AAC) onto a calculated mean tract and extraction of their values along each structure.

Results

There were significant changes of global DTT parameters in the CST (MSA and PSP), CC (PSP) and CG (PSP). Consistent tract-specific variations in DTT parameters could be seen along each tract in the different patient groups and controls. Regional analysis demonstrated significant changes in the anterior CC (MD, RD and FA), CST (MD) and CG (AAC) of patients with PSP compared to controls. Increased MD in CC and CST, as well as decreased AAC in CG, was correlated with a diagnosis of PSP compared to IPD.

Conclusions

DTT can be used for demonstrating disease-specific regional white matter changes in parkinsonian disorders. The anterior portion of the CC was identified as a promising region for detection of neurodegenerative changes in patients with PSP, as well as for differential diagnosis between PSP and IPD.

Comparison of quantitative EEG between patients with Alzheimer's disease and those with Parkinson's disease dementia

OBJECTIVE

Dementia frequently occurs in Parkinson's disease (PD) but its pathophysiological basis is little known. Comparative EEG studies of Alzheimer's disease (AD) and Parkinson's disease dementia (PDD) are still rare, but could provide knowledge on the different pathophysiological mechanisms involved. The objective of the present study was to comparatively evaluate the absolute power and coherence on the EEG for patients with AD and PDD.

METHODS

This study assessed 38 adults with AD, 12 with PDD, 31 with Parkinson's disease without dementia, and 37 controls (CG) by a neurological evaluation, CERAD neuropsychological battery, executive functions tests and qEEG, calculating global absolute powers for the delta, theta, alpha and beta bands and inter- and intra-hemispheric coherences.

RESULTS

The delta and theta powers were highest in PDD and lowest in CG (p<0.05). The beta frontal-occipital inter-hemispheric coherence was highest in PDD (p<0.05). Whereas, alpha and beta frontal inter-hemispheric coherence was highest in PDD and lowest in AD (p<0.05).

CONCLUSION

These results suggest that qEEG power and coherence measures are different in AD and PDD.

SIGNIFICANCE

These qEEG differences must be related to the distinct mechanisms of cortical neural connections in AD and PDD.

Antimicrobial surveillance in idiopathic parkinsonism: indication-specific improvement in hypokinesia following Helicobacter pylori eradication and non-specific effect of antimicrobials for other indications in worsening rigidity

BACKGROUND

Following Helicobacter pylori eradication in a placebo-controlled trial, the hypokinesia of idiopathic parkinsonism improved but flexor rigidity worsened.

METHODS

We surveyed the effect of all antimicrobial prescriptions in 66 patients with idiopathic parkinsonism over a median of 1.9 (interquartile range 0.4, 3.5) years. Initial Helicobacter screening was followed (where positive) by gastric biopsy. Serial lactulose hydrogen breath tests (364 tests) for small intestinal bacterial overgrowth monitored the need to encourage fluid intake and bulk/osmotic laxatives. We measured hypokinesia (401 assessments of mean stride length at free walking speed in 58 patients) and upper limb flexor rigidity (396 assessments in 49).

RESULTS

Following successful H. pylori eradication (12 cases) but not failed (2), stride increased in entire group (including those receiving levodopa), core group (those receiving only longer-t½ antiparkinsonian medication or untreated) and untreated (p = .001 each case). The effect was greater with less antiparkinsonian medication (19 (95% CI, 14, 25) cm/year in untreated). Flexor rigidity was unchanged. Following antimicrobials for other indications (75 courses), hypokinesia was unchanged. However, flexor rigidity increased cumulatively. It increased in core group only after a first course (by (10 (0, 20)%/year, p = .05)), but then in entire, core and untreated after a second course (18 (6, 31), 33 (19, 48) and 29 (12, 48)%/year respectively; p = .002, .001 and .001) and further still after a third (17 (2, 34), 23 (8, 41) and 38 (15, 65)%/year; p = .02, .003 and .001). Initially, 40/66 were lactulose hydrogen breath test positive. Odds for positivity fell with time (by 59 (46, 75)%/year, p = .001) and tended to be lower with Helicobacter positivity (28 (8, 104)%, p = .06), but were unrelated to other antimicrobial interventions.

CONCLUSIONS

Improved hypokinesia following antimicrobials appeared unique to Helicobacter eradication. Rigidity increased following successive antimicrobial exposures for other indications, despite diminishing lactulose hydrogen breath test positivity.

The natural history of Parkinson's disease in the province of Segovia: mortality in a longitudinal study (20-year follow-up)

OBJECTIVE

We determined mortality rates and predictors of survival in 273 patients with Parkinson's disease based on a 20-year follow-up longitudinal study.

MATERIAL AND METHODS

We examined 273 patients with Parkinson's disease during a 20-year follow-up, recruited between 1978 and 1998. All patients were regularly followed at the Department of Neurology until December 31, 1998, or death.

RESULTS

By then, 69 patients had died, crude mortality was rate 4.43, and standardized mortality ratio for the total patient group was 1.39 (95% CI, 1.10-1.50). As Parkinson's disease is a chronic progressive disorder in adult life, disease-related mortality would be expected to increase in later stages after 15 or 20 years. Mean age at death in our cohort was 78.27 (95% CI, 76.90-79.20). Median time of death was 11 years (95% CI, 9.50-12.49). Independent predictors of mortality during the follow-up were age at onset (hazard ratio, 1.05; 95% CI, 1.01-1.09; P = 0.01), clinical form - akinesia and rigidity (hazard ratio, 2.20; 95% CI, 1.06-4.88; P = 0.03) - and treatment with dopaminergic agonist (hazard ratio, 0.49; 95% CI, 0.23-1.03; P = 0.06). Cardiovascular disease was the most frequent cause of death in 42%.

CONCLUSIONS

This study suggests a link between mortality with age of onset and treatment without dopamine agonists as initial treatment. So, there is an association between decreased mortality and tremor as initial clinical forms at onset.

A systematic review of biomarkers for disease progression in Parkinson's disease

Background

Using surrogate biomarkers for disease progression as endpoints in neuroprotective clinical trials may help differentiate symptomatic effects of potential neuroprotective agents from true disease-modifying effects. A systematic review was undertaken to determine what biomarkers for disease progression in Parkinson’s disease (PD) exist.

Methods

MEDLINE and EMBASE (1950–2010) were searched using five search strategies. Abstracts were assessed to identify papers meriting review in full. Studies of participants with idiopathic PD diagnosed by formal criteria or clearly described clinical means were included. We made no restriction on age, disease duration, drug treatment, or study design. We included studies which attempted to draw associations between any tests used to investigate disease progression and any clinical measures of disease progression. The electronic search was validated by hand-searching the two journals from which most included articles came.

Results

183 studies were included: 163 (89%) cross-sectional, 20 (11%) longitudinal. The electronic search strategy had a sensitivity of 71.4% (95% CI 51.1-86.0) and a specificity of 97.1% (95% CI 96.5-97.7). In longitudinal studies median follow-up was 2.0 years (IQR 1.1-3.5). Included studies were generally poor quality - cross-sectional with small numbers of participants, applying excessive inclusion/exclusion criteria, with flawed methodologies and simplistic statistical analyses.

Conclusion

We found insufficient evidence to recommend the use of any biomarker for disease progression in PD clinical trials, which may simply reflect the poor quality of research in this area. We therefore present a provisional ‘roadmap’ for conducting future disease progression biomarker studies, and recommend new quality criteria by which future studies may be judged.

Delayed emergence of a parkinsonian disorder or dementia in 81% of older men initially diagnosed with idiopathic rapid eye movement sleep behavior disorder: a 16-year update on a previously reported series

OBJECTIVE

To provide a 16-year update from the authors' 1996 report documenting a 38% conversion from idiopathic rapid eye movement sleep behavior disorder (iRBD) to a parkinsonian disorder at a mean interval of nearly 13 years after the onset of iRBD in a series of 29 males > or =50 years old.

METHODS

The methods of evaluation, diagnosis and follow-up were previously described in the 1996 report. All patients had video-polysomnography (vPSG) confirmed RBD.

RESULTS

80.8% (21/26) of patients who were initially diagnosed with iRBD eventually developed parkinsonism/dementia (three of the original 29 patients were lost to follow-up). The distribution of diagnoses was as follows: n=13, Parkinson's disease (PD); n=3, dementia with Lewy bodies (DLB); n=1, dementia (unspecified; profound); n=2, multiple system atrophy (MSA); n=2, clinically diagnosed Alzheimer's Disease (AD) with autopsy-confirmed combined AD plus Lewy body disease pathology. Among the 21 iRBD "converters," the mean age (±SD) of iRBD onset was 57.7±7.7 years; mean age (±SD) of parkinsonism/dementia onset was 71.9±6.6 years; and mean interval (±SD) from iRBD onset to parkinsonism/dementia onset was 14.2±6.2 years (range: 5-29 years).

CONCLUSION

The vast majority of men > or =50 years old initially diagnosed with iRBD in this study eventually developed a parkinsonian disorder/dementia, often after a prolonged interval from onset of iRBD, with the mean interval being 14 years while the range extended to 29 years. Also, the specificity of iRBD converting to parkinsonism/dementia is striking. These findings carry important clinical and research implications in the convergent fields of sleep medicine, neurology, and neuroscience, and identify an optimal clinical group for conducting prospective research studies utilizing putative neuroprotective agents to delay the emergence of, or halt the progression to, parkinsonism and/or cognitive impairment as manifestations of either PD, DLB or MSA.

Mood response to deep brain stimulation of the subthalamic nucleus in Parkinson's disease

Deep brain stimulation of the subthalamic nucleus (STN DBS) in Parkinson's disease (PD) improves motor functioning but has variable effects on mood. Little is known about the relationship between electrode contact location and mood response. The authors identified the anatomical location of electrode contacts and measured mood response to stimulation with the Visual Analog Scale in 24 STN DBS PD patients. Participants reported greater positive mood and decreased anxiety and apathy with bilateral and unilateral stimulation. Left DBS improved mood more than right DBS. Right DBS-induced increase in positive mood was related to more medial and dorsal contact locations. These results highlight the functional heterogeneity of the STN.

Higher iron in the red nucleus marks Parkinson's dyskinesia

Dopamine cell loss and increased iron in the substantia nigra (SN) characterize Parkinson's disease (PD), with cerebellar involvement increasingly recognized, particularly in motor compensation and levodopa-induced dyskinesia (LID) development. Because the red nucleus (RN) mediates cerebellar circuitry, we hypothesized that RN iron changes might reflect cerebellum-related compensation, and/or the intrinsic capacity for LID development. We acquired high resolution magnetic resonance images from 23 control and 38 PD subjects (12 with PD and history of LID [PD+DYS]) and 26 with PD and no history of LID (PD-DYS). Iron content was estimated from bilateral RN and SN transverse relaxation rates (R2*). PD subjects overall displayed higher R2* values in both the SN and RN. RN R2* values correlated with off-drug Unified Parkinson's Disease Rating Scale-motor scores, but not disease duration or drug dosage. RN R2* values were significantly higher in PD+DYS compared with control and PD-DYS subjects; control and PD-DYS subjects did not differ. The association of higher RN iron content with PD-related dyskinesia suggests increased iron content is involved in, or reflects, greater cerebellar compensatory capacity and thus increased likelihood of LID development.

Leukocyte-subset counts in idiopathic parkinsonism provide clues to a pathogenic pathway involving small intestinal bacterial overgrowth. A surveillance study

BACKGROUND

Following Helicobacter pylori eradication in idiopathic parkinsonism (IP), hypokinesia improved but flexor-rigidity increased. Small intestinal bacterial-overgrowth (SIBO) is a candidate driver of the rigidity: hydrogen-breath-test-positivity is common in IP and case histories suggest that Helicobacter keeps SIBO at bay.

METHODS

In a surveillance study, we explore relationships of IP-facets to peripheral immune/inflammatory-activation, in light of presence/absence of Helicobacter infection (urea-breath- and/or stool-antigen-test: positivity confirmed by gastric-biopsy) and hydrogen-breath-test status for SIBO (positivity: >20 ppm increment, 2 consecutive 15-min readings, within 2h of 25G lactulose). We question whether any relationships found between facets and blood leukocyte subset counts stand in patients free from anti-parkinsonian drugs, and are robust enough to defy fluctuations in performance consequent on short t½ therapy.

RESULTS

Of 51 IP-probands, 36 had current or past Helicobacter infection on entry, 25 having undergone successful eradication (median 3.4 years before). Thirty-four were hydrogen-breath-test-positive initially, 42 at sometime (343 tests) during surveillance (2.8 years). Hydrogen-breath-test-positivity was associated inversely with Helicobacter-positivity (OR 0.20 (95% CI 0.04, 0.99), p<0.05).In 38 patients (untreated (17) or on stable long-t½ IP-medication), the higher the natural-killer count, the shorter stride, slower gait and greater flexor-rigidity (by mean 49 (14, 85) mm, 54 (3, 104) mm.s-1, 89 (2, 177) Nm.10-3, per 100 cells.μl-1 increment, p=0.007, 0.04 & 0.04 respectively, adjusted for patient characteristics). T-helper count was inversely associated with flexor-rigidity before (p=0.01) and after adjustment for natural-killer count (-36(-63, -10) Nm.10-3 per 100 cells.μl-1, p=0.007). Neutrophil count was inversely associated with tremor (visual analogue scale, p=0.01). Effect-sizes were independent of IP-medication, and not masked by including 13 patients receiving levodopa (except natural-killer count on flexor-rigidity). Cellular associations held after allowing for potentially confounding effect of hydrogen-breath-test or Helicobacter status. Moreover, additional reduction in stride and speed (68 (24, 112) mm & 103 (38, 168) mm.s-1, each p=0.002) was seen with Helicobacter-positivity. Hydrogen-breath-test-positivity, itself, was associated with higher natural-killer and T-helper counts, lower neutrophils (p=0.005, 0.02 & 0.008).

CONCLUSION

We propose a rigidity-associated subordinate pathway, flagged by a higher natural-killer count, tempered by a higher T-helper, against which Helicobacter protects by keeping SIBO at bay.

The presymptomatic period in a patient with idiopathic parkinsonism

A 68-year-old, normal female volunteer was scanned by positron emission tomography (PET) with [(18)F]6-L-fluorodopa (FD). Striatal FD uptake was in the high normal range. Subsequently, she developed parkinsonism 3.7 years after the scan. A repeat FD PET scan revealed a significant reduction of FD uptake by 20% over the 5.2 year interval. Our observations suggest a relatively short presymptomatic period with fast initial losses of nigral neurons in idiopathic parkinsonism.

Survival in Parkinson's disease: the effect of dementia

In order to evaluate the effect of dementia on survival in Parkinson 's disease (PD), we followed a series of 250 PD over a period of 5 years. Dementia was determined according to DSM-III-R criteria. Survival analysis of PD patients with dementia vs. without dementia was performed using entry date as starting point. Cox model was used for evaluation of variables associated with mortality in this sample. Upon inclusion to the study, dementia was diagnosed in 38% of our patients. At the end of the follow-up period, the cumulative death rates were 39% among the demented patients and 34% among the non-demented ones (chi(2)=3.2, df=1, p=0.07). Advanced age and, but marginally, cognitive deterioration were associated with reduced survival [Exp(beta)=3.4, p=0.005 and Exp(beta)=1.3, p=0.06, respectively].

Risk factors for cerebral arteriosclerosis in Parkinson's disease

A previous study showed a lower incidence of ischemic stroke in patients with Parkinson's disease (PD) than in controls. It has been speculated that this may be related to less severe atherosclerosis in PD. In this study we examined the magnetic resonance imaging (MRI) and blood chemistry in 106 parkinsonian patients and compared the data with those from control cases. Abnormal MRI findings (état criblé, lacunar infarctions or periventricular hyperintensity) were found in 55.7% of cases. No case of cortical artery infarction was found. In comparison with a control population, the PD group showed a lower frequency of hypercholesterolemia, a higher frequency of low HDL cholesterol and a lower frequency of obesity. These results suggest that patients with PD have a reduction in risk factors for cortical artery infarction.

Vitamin D receptor gene polymorphism and its association with Parkinson's disease in Chinese Han population

Vitamin D plays an important role in neurodegenerative disorders as a crucial neuro-immunomodulator, and accumulating data have provided evidence for that vitamin D receptor (VDR) gene is a candidate gene for susceptibility to Parkinson's disease (PD). In this study, we performed a case-control study to demonstrate whether the risk for the development of onset of sporadic PD might be influenced by VDR gene polymorphisms in a Chinese cohort. Two hundred and sixty PD patients and 282 matched-healthy controls were genotyped for two representative single nucleotide polymorphisms (SNPs) in VDR gene (FokI C/T and BsmI G/A) by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis in. Results from our study revealed that FokI C allele carriers were likely to associate with an increased risk of PD (P=0.004) as well as early-onset PD (EOPD) (P=0.010). Moreover, the frequency of FokI C allele was significantly increased in PD group and late-onset PD (LOPD) group relative to the control groups respectively (P=0.023 and P=0.033, respectively). For BsmI polymorphisms, no significant difference in genotype or allele distribution was found between PD patients and the controls, as well as gender- and age-related differences between PD patients and the controls subgroup. This study demonstrated a possible association between the VDR FokI T/C polymorphism and PD, indicating that VDR polymorphisms may well change genetic susceptibility to sporadic PD in a Han Chinese population.

WITHDRAWN: Coenzyme Q10 for Parkinson's disease

BACKGROUND

A number of preclinical studies in both in vitro and in vivo models of Parkinson's disease have demonstrated that coenzyme Q10 can protect the nigrostriatal dopaminergic system. Some clinical trials have looked at the neuroprotective effects of coenzyme Q10 in patients with early and midstage Parkinson's disease.

OBJECTIVES

To assess the evidence from randomized controlled trials on the efficacy and safety of treatment with coenzyme Q10 compared to placebo in patients with early and midstage Parkinson's disease.

SEARCH METHODS

We searched the Cochrane Movment Disorders Group Trials Register, CENTRAL (The Cochrane Library 2009, Issue 4), MEDLINE (January 1966 to March 2011), and EMBASE (January 1985 to March 2011). We handsearched the references quoted in the identified trials, congress reports from the most important neurological association and movement disorder societies in Europe and America (March 2011), checked reference lists of relevant studies and contacted other researchers.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared coenzyme Q10 to placebo for patients who suffered early and midstage primary Parkinson's disease. Studies in which the method of randomization or concealment were unknown were included. Cross-over studies were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. All disagreements were resolved by consensus between authors and were explained. We attempted to contact the authors of studies for further details if any data were missing and to establish the characteristics of unpublished trials through correspondence with the trial coordinator or principal investigator. Adverse effects information was collected from the trials.

MAIN RESULTS

Four randomized, double-blind, placebo-controlled trials with a total of 452 patients met the inclusion criteria and were included in the review. In overall, there were improvements in activities of daily living (ADL) UPDRS (WMD -3.12, 95% CI -5.88 to -0.36) and Schwab and England (WMD 4.43, 95% CI 0.05 to 8.81) for coenzyme Q10 at 1200 mg/d for 16 months versus placebo.In safety outcomes, only the risk ratios (RR) of pharyngitis (RR 1.04, 95% CI 0.18 to 5.89) and diarrhea (RR 1.39, 95% CI 0.62 to 3.16) are mild elevated between coenzyme Q10 therapy and placebo and there were no differences in the number of withdrawals due to adverse effects (RR 0.61, 95% CI 0.23 to 1.62).

AUTHORS' CONCLUSIONS

Coenzyme Q10 therapy with 1200 mg/d for 16 months was well tolerated by patients with Parkinson's disease. The improvements in ADL UPDRS and Schwab and England were positive, but it need to be further confirmed by larger sample. For total and other subscores of UPDRS, the effects of coenzyme Q10 seemed to be less clear.

Effect of subthalamic deep brain stimulation on turning kinematics and related saccadic eye movements in Parkinson disease

BACKGROUND

Persons with Parkinson disease (PD) experience turning difficulty, often leading to freezing of gait and falls. Visual information plays a significant role in locomotion and turning, and while the effects of deep brain stimulation (DBS) on oculomotor function have been well documented, the effects of DBS on oculomotor function during turning and on turning itself have yet to be fully elucidated.

OBJECTIVE

To determine the effects of STN DBS on turning performance and related oculomotor performance in PD.

METHODS

Eleven subjects with PD and DBS of the subthalamic nucleus performed a seated voluntary saccade task and standing 180° turns in DBS OFF and DBS ON conditions. Oculomotor data were captured using an infrared eye tracking system while segment rotations were measured using 3-D motion capture.

RESULTS

During the seated saccade task, DBS did not improve saccade amplitude or latency. DBS also did not improve gait velocity and stride length during forward walking. During turning, DBS improved turn performance (turn duration), reduced the number of saccades performed during the turns, and increased the amplitude and velocity of the saccade initiating the turn. DBS decreased the intersegmental latencies (eye-head, eye-foot, and head-trunk) but this effect was lost for eye-head and eye-foot after controlling for the duration of the first gait cycle.

CONCLUSIONS

DBS significantly improves turn performance and related oculomotor performance. These findings add to the growing list of therapeutic benefits offered by DBS.

Serum cholesterol and nigrostriatal R2* values in Parkinson's disease

BACKGROUND

The occurrence of Parkinson's disease (PD) is known to be associated both with increased nigrostriatal iron content and with low serum cholesterol and PD, but there has been no study to determine a potential relationship between these two factors.

METHODS

High-resolution MRI (T1-, T2, and multiple echo T2*-weighted imaging) and fasting lipid levels were obtained from 40 patients with PD and 29 healthy controls. Iron content was estimated from mean R2* values (R2* = 1/T2*) calculated for each nigrostriatal structure including substantia nigra, caudate, putamen, and globus pallidus. This was correlated with serum cholesterol levels after controlling for age, gender, and statin use.

RESULTS

In patients with PD, higher serum cholesterol levels were associated with lower iron content in the substantia nigra (R = -0.43, p = 0.011 for total-cholesterol, R = -0.31, p = 0.080 for low-density lipoprotein) and globus pallidus (R = -0.38, p = 0.028 for total-cholesterol, R = -0.27, p = 0.127 for low-density lipoprotein), but only a trend toward significant association of higher total-cholesterol with lower iron content in the striatum (R = -0.34, p = 0.052 for caudate; R = -0.32, p = 0.061 for putamen). After adjusting for clinical measures, the cholesterol-iron relationships held or became even stronger in the substantia nigra and globus pallidus, but weaker in the caudate and putamen. There was no significant association between serum cholesterol levels and nigrostriatal iron content for controls.

CONCLUSIONS

The data show that higher serum total-cholesterol concentration is associated with lower iron content in substantia nigra and globus pallidus in Parkinson's disease patients. Further studies should investigate whether this is mechanistic or epiphenomenological relationship.

Lack of association of polymorphism in miRNA-196a2 with Parkinson's disease risk in a Chinese population

MicroRNAs (miRNAs) are a new class of non-protein coding RNA molecules, which participate in diverse biological pathways. We hypothesized that miRNA-196a2 polymorphism is associated with the risk of Parkinson's disease (PD) in a Chinese population. In a case-control study of 549 PD patients and 736 control subjects frequency matched by age and gender, we genotyped the single-nucleotide polymorphism (SNP) rs11614913 (T>C) in miRNA-196a2, whose target mRNA was alpha-synuclein, and assessed its association with risk of PD by TaqMan Genotyping method. No association was found for the miR-196a2 rs11614913 CT/CC genotype (odds ratio (OR), 0.879, 95% confidence interval (CI), 0.681-1.135 for CT genotype; OR, 1.085, 95% CI, 0.793-1.484 for CC genotype) with risk of PD, compared with the TT genotype. These results suggest that SNP rs11614913 in miRNA-196a2 may not contribute to the susceptibility to PD.

Both coordination and symmetry of arm swing are reduced in Parkinson's disease

OBJECTIVE

A recent study reporting significantly reduced symmetry in arm swing amplitude in early Parkinson's disease (PD), as measured during single strides in a gait laboratory, led to this investigation of arm swing symmetry and coordination over many strides using wearable accelerometers in PD.

METHODS

Forearm accelerations were recorded while eight early PD subjects and eight Controls performed 8-min walking trials. Arm swing asymmetry (ASA), maximal cross-correlation (MXC), and instantaneous relative phase (IRP) of bilateral arm swing were compared between PD and Controls. Correlations between arm swing measurements (ASA and MXC) and Unified PD Rating Scale (UPDRS) scores were estimated.

RESULTS

PD subjects demonstrated significantly higher ASA (p=0.002) and lower MXC (p<0.001) than Controls. The IRP probability distribution for PD was significantly different than Controls (p<0.001), with an angular standard deviation of 67.2° for PD and 50.6° for Controls. Among PD subjects, ASA was significantly correlated with the UPDRS score for the limbs (R(2)=0.58, p=0.049), whereas MXC was significantly correlated with the tremor subscore of the limbs (R(2)=0.64, p=0.031).

DISCUSSION

The study confirms previously reported higher arm swing asymmetry in PD but also shows there is significantly lower MXC and greater IRP variability, suggesting that reduction in bilateral arm coordination may contribute to clinically observed asymmetry in PD. The differential correlation of clinical measures of motor disability with measurements of arm swing during gait is intriguing and deserves further investigation.

Interleukin-10 promoter polymorphisms in Chinese patients with Parkinson's disease

Interleukin-10 (IL-10), an important anti-inflammatory cytokine, may influence the risk for the development of onset of sparadic Parkinson's disease (PD) in the inflammatory process. In this study, two DNA polymorphisms at IL-10 gene promoter (-819 T/C and -592 A/C) were examined in 355 sporadic PD patients and 200 healthy controls in Han Chinese Population. For both polymorphisms, no significant difference in genotype or allele distribution was found between PD patients and the controls. For -819 T/C polymorphisms, there was significant difference in genotype distribution between EOPD (EOPD, <50 years of age) patients and each healthy-matched control subgroup (P=0.011), as well as between female PD patients and each healthy-matched control subgroup (P=0.024), For -592 A/C polymorphisms, there were no significant gender- and age-related differences in genotype distribution between PD patients and the controls subgroup. Results from our study revealed that the IL-10 promoter (-819 and -592) polymorphism is not a risk factor of sporadic Parkinson's disease, but the IL-10 promoter -819 polymorphism is a risk factor of EOPD and female PD patients in Han Chinese population.

SNP rs356219 of the α-synuclein (SNCA) gene is associated with Parkinson's disease in a Chinese Han population

BACKGROUND

Over the last decades, increasing knowledge about the genetic architecture of Parkinson's disease(PD) has provided novel insights into the pathogenesis of the disorder. Recently, several studies in different populations have found a strong association between idiopathic PD and the single-nucleotide polymorphism (SNP) rs356219, which is located in the 3'UTR of the SNCA gene. In this study, we aimed to verify these findings and to explore further the nature of the association in a subset of Chinese Han PD patients.

METHODS

Four hundred and three unrelated patients with sporadic PD and 315 healthy ethnically matched control subjects were recruited consecutively for the study. Patients and normal controls were genotyped for SNCA rs356219 variant by ligase detection reaction (LDR).

RESULTS

A statistically significant difference was found in the frequencies of the single alleles of rs356219 (χ(2) = 12.986,P = 0.002) between PD patients and normal subjects. The distribution of A > G genotypes was different between patients and controls (χ(2) = 13.243, P < 0.001). The OR for subjects with the variant genotypes (AG and GG) was 1.88 (95%CI = 1.27-2.78, P = 0.001). The frequencies of the homozygous genotype for this variant was 42.2% (170 patients), which was significantly higher than that in controls (32.4%, P < 0.001).

CONCLUSION

The results suggested that SNCA rs356219 variant might have an increased risk of susceptibility to PD in a Chinese Han population. Further studies are needed to replicate the association that we found.

Are verbal fluency and nonliteral language comprehension deficits related to depressive symptoms in Parkinson's disease?

Depression in Parkinson's disease (PD) is frequently associated with executive deficits, which can influence nonliteral comprehension and lexical access. This study explores whether depressive symptoms in PD modulate verbal fluency and nonliteral language comprehension. Twelve individuals with PD without depressive symptoms, 13 with PD and depressive symptoms (PDDSs), and 13 healthy controls completed a semantic and phonemic verbal fluency task and an indirect speech acts comprehension task. All groups had the same performance in the phonemic fluency task while the PDDS group was impaired in the semantic task. For the indirect speech act comprehension task, no difference was observed between the groups. However, the PDDS group had difficulty answering direct speech act questions. As some language impairments in PD become apparent when depressive symptoms are associated with the disease, it would appear to be important to take the presence of depressive symptoms into account when evaluating language abilities in PD.

Significance of apparent diffusion coefficient measurement for the differential diagnosis of multiple system atrophy, progressive supranuclear palsy, and Parkinson's disease: evaluation by 3.0-T MR imaging

INTRODUCTION

The clinical differentiation of Parkinson's disease (PD) from multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) may be challenging, especially in their early stages. The aim of this study was to evaluate the utility of apparent diffusion coefficient (ADC) measurement to distinguish among these degenerative disorders.

METHODS

Twenty-five MSA, 20 PSP, and 17 PD patients and 18 healthy controls were retrospectively studied. Axial diffusion-weighted and T2-weighted images were obtained using a 3-T MR system. Regions of interest (ROIs) were precisely placed in the midbrain, pons, putamen, globus pallidus, caudate nucleus, thalamus, superior cerebellar peduncle, middle cerebellar peduncle, cerebellar white matter, and cerebellar dentate nucleus, and the regional ADC (rADC) value was calculated in each ROI.

RESULTS

In MSA, rADC values in the pons, middle cerebellar peduncle, cerebellar white matter, and cerebellar dentate nucleus were significantly higher than in PSP, PD, and controls. Furthermore, rADC values in the posterior putamen were significantly higher in MSA than in PSP and controls. In PSP, rADC values were significantly higher in the globus pallidus and midbrain than in MSA, PD, and controls. Furthermore, rADC values in the caudate nucleus and superior cerebellar peduncle were significantly higher in PSP than in MSA and controls. In PD, there were no significant differences in the rADC values compared to in MSA, PSP, and controls in all regions.

CONCLUSION

Evaluation of rADC values in characteristic lesions in MSA, PSP, and PD by placing ROIs using 3-T systems can provide useful additional information for differentiating these disorders.

Movement orientation switching with the eyes and lower limb in Parkinson disease

Difficulty switching between motor programs is a proposed cause of motor blocks in Parkinson disease (PD). Switching from one movement to another has been studied in the upper extremity and during postural control tasks, but not yet in the eyes and lower limb in PD. The purpose of this study was to compare movement orientation switching ability between people with PD and age-matched controls (CON) and to determine if switching ability is correlated between the eyes and lower limb. Twenty-six persons with PD and 19 age-matched controls participated. Movement orientation switching was studied in a seated position with the head fixed in a chinrest. In response to a randomly generated tone, participants switched from a continuous back-and-forth movement in either the horizontal or vertical orientation to the opposite orientation as quickly as possible. Lower limb movements were performed with the great toe pointing back and forth between targets positioned on a 45° angled floor platform. Eye movements were back and forth between the same targets. Eye and lower limb switch time was reduced in PD (p<0.01), but after normalizing switch time to movement velocity, no differences existed between PD and CON. Eye and lower limb switch times were correlated in PD (r=0.513, p<0.01) but not in CON. In PD, switch time and movement velocity of the lower limb, but not the eyes, correlated with bradykinesia and postural instability/gait. Our results suggest that individuals with PD experience movement-switching deficits with both the eyes and lower limb, perhaps driven by overall bradykinesia.

Longitudinal evolution of compensatory changes in striatal dopamine processing in Parkinson's disease

Parkinson's disease is a relentlessly progressive neurodegenerative disease. Breakdown of compensatory mechanisms influencing putaminal dopamine processing could contribute to the progressive motor symptoms. We studied a cohort of 78 subjects (at baseline) with sporadic Parkinson's disease and 35 healthy controls with multi-tracer positron emission tomography scans to investigate the evolution of adaptive mechanisms influencing striatal dopamine processing in Parkinson's disease progression. Presynaptic dopaminergic integrity was assessed with three radioligands: (i) [(11)C](±)dihydrotetrabenazine, to estimate the density of vesicular monoamine transporter type 2; (ii) [(11)C]d-threo-methylphenidate, to label the dopamine transporter; and (iii) 6-[(18)F]fluoro-L-DOPA, to assess the activity of aromatic amino acid decarboxylase and storage of 6-[(18)F]-fluorodopamine in synaptic vesicles. The subjects with Parkinson's disease and the healthy controls underwent positron emission tomography scans at the initial visit and after 4 and 8 years of follow-up. Non-linear multivariate regression analyses with random effects were utilized to model the longitudinal changes in tracer values in the putamen standardized relative to normal controls. We found evidence for possible upregulation of dopamine synthesis and downregulation of dopamine transporter in the more severely affected putamen in the early stage of Parkinson's disease. The standardized 6-[(18)F]fluoro-L-DOPA and [(11)C]d-threo-methylphenidate values tended to approach [(11)C](±)dihydrotetrabenazine values in the putamen in later stages of disease (i.e. for [(11)C](±)dihydrotetrabenazine values <25% of normal), when the rates of decline in the positron emission tomography measurements were similar for all the markers. Our data suggest that compensatory mechanisms decline as Parkinson's disease progresses. This breakdown of compensatory strategies in the putamen could contribute to the progression of motor symptoms in advanced disease.

Coenzyme Q10 for Parkinson's disease

BACKGROUND

A number of preclinical studies in both in vitro and in vivo models of Parkinson's disease have demonstrated that coenzyme Q10 can protect the nigrostriatal dopaminergic system. Some clinical trials have looked at the neuroprotective effects of coenzyme Q10 in patients with early and midstage Parkinson's disease.

OBJECTIVES

To assess the evidence from randomized controlled trials on the efficacy and safety of treatment with coenzyme Q10 compared to placebo in patients with early and midstage Parkinson's disease.

SEARCH METHODS

We searched the Cochrane Movment Disorders Group Trials Register, CENTRAL (The Cochrane Library 2009, Issue 4), MEDLINE (January 1966 to March 2011), and EMBASE (January 1985 to March 2011). We handsearched the references quoted in the identified trials, congress reports from the most important neurological association and movement disorder societies in Europe and America (March 2011), checked reference lists of relevant studies and contacted other researchers.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared coenzyme Q10 to placebo for patients who suffered early and midstage primary Parkinson's disease. Studies in which the method of randomization or concealment were unknown were included. Cross-over studies were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. All disagreements were resolved by consensus between authors and were explained. We attempted to contact the authors of studies for further details if any data were missing and to establish the characteristics of unpublished trials through correspondence with the trial coordinator or principal investigator. Adverse effects information was collected from the trials.

MAIN RESULTS

Four randomized, double-blind, placebo-controlled trials with a total of 452 patients met the inclusion criteria and were included in the review. In overall, there were improvements in activities of daily living (ADL) UPDRS (WMD -3.12, 95% CI -5.88 to -0.36) and Schwab and England (WMD 4.43, 95% CI 0.05 to 8.81) for coenzyme Q10 at 1200 mg/d for 16 months versus placebo.In safety outcomes, only the risk ratios (RR) of pharyngitis (RR 1.04, 95% CI 0.18 to 5.89) and diarrhea (RR 1.39, 95% CI 0.62 to 3.16) are mild elevated between coenzyme Q10 therapy and placebo and there were no differences in the number of withdrawals due to adverse effects (RR 0.61, 95% CI 0.23 to 1.62).

AUTHORS' CONCLUSIONS

Coenzyme Q10 therapy with 1200 mg/d for 16 months was well tolerated by patients with Parkinson's disease. The improvements in ADL UPDRS and Schwab and England were positive, but it need to be further confirmed by larger sample. For total and other subscores of UPDRS, the effects of coenzyme Q10 seemed to be less clear.

Risk of falling in Parkinson's disease at the Hoehn-Yahr stage III

BACKGROUND

It is difficult to predict the risk of falling, especially in patients with good motor ability, and the mechanisms underlying the relation between gait patterns and falling in Parkinson's disease (PD) remain unclear. We investigated factors related to falling, including walking speed and time, in patients with Hoehn-Yahr stage III PD.

METHODS

We performed clinical assessments and evaluated balance in 30 patients with PD. Information on falling was obtained from questionnaires and personal interviews. Gait patterns were analyzed with the use of an originally designed, suddenly narrowed path.

RESULTS

Gait velocity was slower in fallers than in non-fallers (p = 0.047). Unified Parkinson's Disease Rating Scale part II (UPDRS part II) score, fear of falling, and gait velocity were significantly related to falling on analysis with a single logistic model. When a multiple logistic model was used, the UPDRS part II score was significantly related to falling (OR: 1.48, p = 0.037, 95% CI: 1.02-2.16).

CONCLUSIONS

Patients with Hoehn-Yahr stage III PD showed slow gait velocity attributed to fear of falling before arrival at a narrowed entrance or while walking on a narrowed path. The UPDRS part II score is significantly related to the risk of future falls.

Reliability in one-repetition maximum performance in people with Parkinson's disease

Strength training is an effective modality to improve muscular strength and functional performance in people with Parkinson's disease (PWP). One-repetition maximum (1-RM) is the gold standard assessment of strength; however, PWP suffer from day-to-day variations in symptom severity and performance characteristics, potentially adversely affecting the reliability of 1-RM performance. Herein, we assessed the reliability of 1-RM in PWP. Forty-six participants completed two sessions of 1-RM testing of knee extension, knee flexion, chest press, and biceps curl at least 72 hours apart. Significantly differences between testing sessions were identified for knee extension (P < 0.001), knee flexion (P = 0.042), and biceps curl (P = 0.001); however, high reliability (ICC > 0.90) was also identified between sessions. Interestingly, almost third of subjects failed to perform better on the second testing session. These findings suggest that 1-RM testing can be safely performed in PWP and that disease-related daily variability may influence 1-RM performance.

Validation of the Japanese translation of the Swallowing Disturbance Questionnaire in Parkinson's disease patients

PURPOSE

The Swallowing Disturbance Questionnaire (SDQ) was developed as a self-rated screening tool for dysphagia in patients with Parkinson's disease (PD). We developed the Japanese version of this questionnaire (SDQ-J), according to the cross-cultural adaptation guidelines, and examined its reliability.

METHODS

Subjects were 61 Japanese patients with PD (mean age, 67.0 ± 9.2 years) who answered the SDQ-J before undergoing videofluoroscopic examination of swallowing (VF). We compared the findings of the questionnaire with the patients' aspiration status during VF.

RESULTS

Cronbach's alpha coefficient for the 15 questions of the SDQ-J was 0.84. According to the SDQ-J, 15 patients (24.6%) were diagnosed with dysphagia, while 9 patients (14.8%) aspirated liquid during VF. The sensitivity and specificity of the SDQ-J in predicting aspiration were 77.8 and 84.6%, respectively; therefore, the SDQ-J significantly predicted aspiration during VF (P < 0.01). The positive predictive value (PPV) and negative predictive value (NPV) for the SDQ-J were 0.46 and 0.96, respectively.

CONCLUSIONS

The SDQ-J appears to be a reliable and useful screening tool for Japanese PD patients with aspiration. As the NPV was higher than the PPV in the SDQ-J, this questionnaire could potentially be used for early identification of severe dysphagia in patients with PD.

Randomized controlled trial of community-based dancing to modify disease progression in Parkinson disease

BACKGROUND

Tango dancing has been effective in improving measures of physical function in people with Parkinson disease (PD). However, all previous studies were institution-based, tested participants on medication, and employed short-term interventions.

OBJECTIVE

To determine the effects of a 12-month community-based tango program for individuals with PD on disease severity and physical function.

METHODS

Sixty-two participants were randomly assigned to a twice weekly, community-based Argentine Tango program or a Control group (no intervention). Participants were assessed off anti-Parkinson medication at baseline, 3, 6, and 12 months. The primary outcome measure was the Movement Disorders Society-Unified Parkinson Disease Rating Scale 3 (MDS-UPDRS-3). Secondary outcome measures were the MDS-UPDRS-1, MDS-UPDRS-2, MiniBESTest balance test; Freezing of Gait Questionnaire (FOG_Q); 6-Minute Walk Test (6MWT); gait velocity for comfortable forward, fast as possible forward, dual task, and backward walking; and Nine-Hole Peg Test (9HPT).

RESULTS

Groups were not different at baseline. Overall, the Tango group improved whereas the Control group showed little change on most measures. For the MDS-UPDRS-3, there was no significant change in the Control group from baseline to 12 months, whereas the Tango group had a reduction of 28.7% (12.8 points). There were significant group by time interactions for MDS-UPDRS-3, MiniBESTest, FOG_Q, 6MWT, forward and dual task walking velocities, and 9HPT in favor of the dance group.

CONCLUSIONS

Improvements in the Tango group were apparent off medication, suggesting that long-term participation in tango may modify progression of disability in PD.

Diurnal salivary cortisol concentrations in Parkinson's disease: increased total secretion and morning cortisol concentrations

BACKGROUND

Parkinson's disease (PD) is a chronic neurodegenerative disorder. There is limited knowledge about the function of the hypothalamic-pituitary-adrenal axis in PD. The primary aim of this prospective study was to analyze diurnal salivary cortisol concentrations in patients with PD and correlate these with age, gender, body mass index (BMI), duration of PD, and pain. The secondary aim was to compare the results with a healthy reference group.

METHODS

Fifty-nine PD patients, 35 women and 24 men, aged 50-79 years, were recruited. The reference group comprised healthy individuals matched for age, gender, BMI, and time point for sampling. Salivary cortisol was collected at 8 am, 1 pm, and 8 pm, and 8 am the next day using cotton-based Salivette(®) tubes and analyzed using Spectria(®) Cortisol I(125). A visual analog scale was used for estimation of pain.

RESULTS

The median cortisol concentration was 16.0 (5.8-30.2) nmol/L at 8 am, 5.8 (3.0-16.4) at 1 pm, 2.8 (1.6-8.0) at 8 pm, and 14.0 (7.5-28.7) at 8 am the next day. Total secretion and rate of cortisol secretion during the day (8 am-8 pm) and the concentration of cortisol on the next morning were lower (12.5 nmol/L) in the reference group. No significant correlations with age, gender, BMI, duration of PD, Hoehn and Yahr score, Unified Parkinson's Disease Rating Scale III score, gait, pain, or cortisol concentrations were found.

CONCLUSION

The neurodegenerative changes in PD does not seem to interfere with the hypothalamic-pituitary-adrenal axis. Salivary cortisol concentrations in PD patients were increased in the morning compared with the reference group, and were not influenced by motor dysfunction, duration of disease, or coexistence of chronic or acute pain.

Brain perfusion differences in parkinsonian disorders

We aimed to objectively examine the brain perfusion differences between PD, Parkinson variant of multiple system atrophy, and progressive supranuclear palsy. (99m) Tc ethylcysteinate dimer single-photon emission CT (SPECT) was performed in 28 patients with PD, 12 with Parkinson variant of multiple system atrophy, 19 with progressive supranuclear palsy, and 17 age- and sex-matched control subjects. A voxel-by-voxel group analysis, using statistical parametric mapping 8, was performed to detect the differences of regional cerebral blood flow among three diseases and control groups. Regional cerebral blood flow was measured using the noninvasive Patlak plot method and calculated using a fully automated region of interest technique. Progressive supranuclear palsy showed decreased regional cerebral blood flow in the cingulate gyrus and thalamus, whereas Parkinson variant of multiple system atrophy showed decreased regional cerebral blood flow in the cerebellum, compared with other patients and controls. Regional cerebral blood flow in the thalamus could be used to discriminate progressive supranuclear palsy from other diseases and control subjects with high sensitivity. These findings suggest that parkinsonian disorders, such as PD, Parkinson variant of multiple system atrophy, and progressive supranuclear palsy show a distinct SPECT pattern in the frontal cortex, thalamus, and cerebellum. Moreover, the measurements of regional cerebral blood flow in the thalamus and cerebellum may be helpful in screening for the differential diagnosis of parkinsonian syndrome.

Epidemiology and etiology of Parkinson's disease: a review of the evidence

The etiology of Parkinson's disease (PD) is not well understood but likely to involve both genetic and environmental factors. Incidence and prevalence estimates vary to a large extent-at least partly due to methodological differences between studies-but are consistently higher in men than in women. Several genes that cause familial as well as sporadic PD have been identified and familial aggregation studies support a genetic component. Despite a vast literature on lifestyle and environmental possible risk or protection factors, consistent findings are few. There is compelling evidence for protective effects of smoking and coffee, but the biologic mechanisms for these possibly causal relations are poorly understood. Uric acid also seems to be associated with lower PD risk. Evidence that one or several pesticides increase PD risk is suggestive but further research is needed to identify specific compounds that may play a causal role. Evidence is limited on the role of metals, other chemicals and magnetic fields. Important methodological limitations include crude classification of exposure, low frequency and intensity of exposure, inadequate sample size, potential for confounding, retrospective study designs and lack of consistent diagnostic criteria for PD. Studies that assessed possible shared etiological components between PD and other diseases show that REM sleep behavior disorder and mental illness increase PD risk and that PD patients have lower cancer risk, but methodological concerns exist. Future epidemiologic studies of PD should be large, include detailed quantifications of exposure, and collect information on environmental exposures as well as genetic polymorphisms.

Combined R2* and diffusion tensor imaging changes in the substantia nigra in Parkinson's disease

Recent magnetic resonance imaging studies suggest an increased transverse relaxation rate and reduced diffusion tensor imaging fractional anisotropy values in the substantia nigra in Parkinson's disease. The transverse relaxation rate and fractional anisotropy changes may reflect different aspects of Parkinson's disease-related pathological processes (ie, tissue iron deposition and microstructure disorganization). This study investigated the combined changes of transverse relaxation rate and fractional anisotropy in the substantia nigra in Parkinson's disease. High-resolution magnetic resonance imaging (T2-weighted, T2*, and diffusion tensor imaging) were obtained from 16 Parkinson's disease patients and 16 controls. Bilateral substantia nigras were delineated manually on T2-weighted images and coregistered to transverse relaxation rate and fractional anisotropy maps. The mean transverse relaxation rate and fractional anisotropy values in each substantia nigra were then calculated and compared between Parkinson's disease subjects and controls. Logistic regression, followed by receiver operating characteristic curve analysis, was employed to investigate the sensitivity and specificity of the combined measures for differentiating Parkinson's disease subjects from controls. Compared with controls, Parkinson's disease subjects demonstrated increased transverse relaxation rate (P<.0001) and reduced fractional anisotropy (P=.0365) in the substantia nigra. There was no significant correlation between transverse relaxation rate and fractional anisotropy values. Logistic regression analyses indicated that the combined use of transverse relaxation rate and fractional anisotropy values provides excellent discrimination between Parkinson's disease subjects and controls (c-statistic=0.996) compared with transverse relaxation rate (c-statistic=0.930) or fractional anisotropy (c-statistic=0.742) alone. This study shows that the combined use of transverse relaxation rate and fractional anisotropy measures in the substantia nigra of Parkinson's disease enhances sensitivity and specificity in differentiating Parkinson's disease from controls. Further studies are warranted to evaluate the pathophysiological correlations of these magnetic resonance imaging measurements and their effectiveness in assisting in diagnosing Parkinson's disease and following its progression.

Levodopa and the feedback process on set-shifting in Parkinson's disease

OBJECTIVE

To study the interaction between levodopa and the feedback process on set-shifting in Parkinson's disease (PD).

METHODS

Functional magnetic resonance imaging (fMRI) studies were performed on 13 PD subjects and 17 age-matched healthy controls while they performed a modified card-sorting task. Experimental time periods were defined based on the types of feedback provided. PD subjects underwent the fMRI experiment twice, once during "off" medication (PDoff) and again after levodopa replacement (PDon).

RESULTS

Compared with normal subjects, the cognitive processing times were prolonged in PDoff but not in PDon subjects during learning through positive outcomes. The ability to set-shift through negative outcomes was not affected in PD subjects, even when "off" medication. Intergroup comparisons showed the lateral prefrontal cortex was deactivated in PDoff subjects during positive feedback learning, especially following internal feedback cues. The cortical activations were increased in the posterior brain regions in PDoff subjects following external feedback learning, especially when negative feedback cues were provided. Levodopa replacement did not completely restore the activation patterns in PD subjects to normal although activations in the corticostriatal loops were restored.

CONCLUSION

PD subjects showed differential ability to set-shift, depending on the dopamine status as well as the types of feedback cues provided. PD subjects had difficulty performing set-shift tasks through positive outcomes when "off" medication, and showed improvement after levodopa replacement. The ability to set-shift through negative feedback was not affected in PD subjects even when "off" medication, possibly due to compensatory changes outside the nigrostriatal dopaminergic pathway.

Effect of chronic kidney disease on excessive daytime sleepiness in Parkinson disease

BACKGROUND AND PURPOSES

Excessive daytime sleepiness (EDS) is a common sleep disorder in patients with Parkinson disease (PD). Non-ergot dopamine agonists increase the risk of unanticipated sleep episodes.

OBJECTIVE

  We aimed to assess the influence of renal function on EDS in patients with PD.

METHODS

Sixty-two patients treated with ropinirole or pramipexole were recruited for this study. We evaluated the historical and clinical characteristics including the motor symptom rating scales, Epworth Sleepiness Scale (ESS), and estimated glomerular filtration rate (eGFR). An ESS score of 10 or greater was defined as EDS. Participants with eGFR < 60 ml/min/1.73 m(2) were determined to have chronic kidney disease (CKD). Multiple logistic regression analysis was performed to determine the predictive factors of EDS.

RESULTS

Chronic kidney disease was found to be a significant predictive factor for EDS in all patients (P = 0.014). We observed a negative correlation between the severity of daytime sleepiness and renal function in patients treated with pramipexole alone (r(s) = -0.637, P < 0.001).

CONCLUSIONS

Chronic kidney disease may be a risk factor for EDS, especially in patients treated with pramipexole, which is directly excreted in the urine.

Age-specific progression of nigrostriatal dysfunction in Parkinson's disease

OBJECTIVE

To investigate in vivo the impact of age on nigrostriatal dopamine dysfunction in Parkinson's disease (PD).

METHODS

PD patients (n = 78) and healthy control subjects (n = 35) underwent longitudinal positron emission tomography assessments using 3 presynaptic dopamine markers: (1) [¹¹C](±)dihydrotetrabenazine (DTBZ), to estimate the density of the vesicular monoamine transporter type 2; (2) [¹¹C]d-threo-methylphenidate, to estimate the density of the plasma membrane dopamine transporter; and (3) 6-[¹⁸F]-fluoro-L-dopa, to estimate the activity of the enzyme dopa-decarboxylase.

RESULTS

The study comprised 438 PD scans and 241 control scans (679 scans in total). At symptom onset, the loss of putamen DTBZ binding was substantially greater in younger compared to older PD patients (p = 0.015). Remarkably, however, the rate of progression of DTBZ binding loss was significantly slower in younger patients (p < 0.05). The estimated presymptomatic phase of the disease spanned more than 2 decades in younger patients, compared to 1 decade in older patients.

INTERPRETATION

Our results suggest that, compared to older patients, younger PD patients progress more slowly and are able to endure more damage to the dopaminergic system before the first motor symptoms appear. These observations suggest that younger PD patients have more efficient compensatory mechanisms.

Analysis on the susceptibility genes in two chinese pedigrees with familial Parkinson's disease

Objective. To screen the susceptibility genes in Chinese pedigrees with early-onset familial Parkinson's disease (FPD). Methods. Fifty-one genomic DNA samples extracted from two Chinese pedigrees with FPD, the alpha-synuclein genes (SNCA), the leucine-rich repeat kinase 2(LRRK2), PINK1(PTEN-induced putative kinase 1), PARK7(Protein DJ1), PARK2(Parkinson juvenile disease protein 2), the glucocerebrosidase (GBA), and ATP(Ezrin-binding protein PACE-1), were sequenced by the use of polymerase chain reaction (PCR) technique. The gene dose of SNCA was checked. Results. There were only two missense mutations observed, respectively, at exon 5 of LRRK2 and exon 10 of PARK2, and both were enrolled in SNPs. Conclusion. No meaningful mutations could be detected, and other susceptibility genes should be detected in FDP patients in China.

Putaminal magnetic resonance imaging features at various magnetic field strengths in multiple system atrophy

We delineated the effects of magnetic field strength on signal intensities to facilitate the specific findings of multiple system atrophy (MSA). Fifteen patients with probable MSA were imaged by 0.35T fast spin-echo (FSE), 1.5T FSE, and 3.0T FSE using a consistent protocol, testing all field strengths on the same day. Sixty patients with probable Parkinson's disease (PD) also underwent imaging. Moderate or marked hyperintensity at the dorsolateral outer putaminal margin, hyperintensity of the putaminal body, hypointensity relative to the globus pallidus at the dorsolateral putaminal margin, and infratentorial signal changes were evaluated as specific findings for MSA. As the field strength increased, the occurrence of hyperintensity both at the dorsolateral outer putaminal margin and of the putaminal body decreased, while the occurrence of hypointensity at the dorsolateral putaminal margin increased in MSA. The occurrence of uniform mild hyperintensity of the outer putaminal margin was evident in 7% at 0.35T, 40% at 1.5T, and 47% at 3.0T in MSA and in 5% at 0.35T, 60% at 1.5T, and 75% at 3.0T in PD. However, no PD patients showed hyperintensity at the dorsolateral outer putaminal margin and that of the putaminal body. Putaminal magnetic resonance imaging (MRI) findings in MSA were altered considerably by magnetic field strength. The severity and distribution of signal changes are important for assessing putaminal MRI findings in MSA.