Differences in age at onset and familial aggregation between clinical types of idiopathic Parkinson's disease

Clinical Characteristics of Patients with De Novo Parkinson's Disease and a Positive Family History

Background/Objectives: A family history of Parkinson's disease (PD) is an important risk factor for developing PD. Because only a few studies have investigated the clinical characteristics of PD patients based on family history, this study compared the clinical characteristics of PD patients with and without a family history of PD. Methods: The study involved 356 patients with de novo PD. The data on the patients' PD family histories were obtained from the patients and their caregivers. Motor and non-motor PD symptoms were assessed using the appropriate scales. Results: Out of the 356 PD patients, 26 (7.3%) had a family history of PD. Compared with patients without a family history of PD, those with a family history of PD tended to be younger at diagnosis (67.9 years vs. 62.2 years, respectively; p = 0.009) and exhibited significantly more severe rigidity (p = 0.036). Motor subtype was not different between the PD patients with and without a family history. PD patients with a family history experienced significantly fewer falls/cardiovascular symptoms within the Non-Motor Symptoms Scale domains (p = 0.001) compared to their counterparts, although this was not statistically significant upon adjusting for age (p = 0.119). Conclusions: In de novo PD patients, having a family history of PD is associated with a younger age at diagnosis and more severe rigidity.

Emerging perspectives on precision therapy for Parkinson's disease: multidimensional evidence leading to a new breakthrough in personalized medicine

PD is a prevalent and progressive neurodegenerative disorder characterized by both motor and non-motor symptoms. Genes play a significant role in the onset and progression of the disease. While the complexity and pleiotropy of gene expression networks have posed challenges for gene-targeted therapies, numerous pathways of gene variant expression show promise as therapeutic targets in preclinical studies, with some already in clinical trials. With the recognition of the numerous genes and complex pathways that can influence PD, it may be possible to take a novel approach to choose a treatment for the condition. This approach would be based on the symptoms, genomics, and underlying mechanisms of the disease. We discuss the utilization of emerging genetic and pathological knowledge of PD patients to categorize the disease into subgroups. Our long-term objective is to generate new insights for the therapeutic approach to the disease, aiming to delay and treat it more effectively, and ultimately reduce the burden on individuals and society.

Future Directions for Developing Non-dopaminergic Strategies for the Treatment of Parkinson's Disease

The symptomatic treatment of Parkinson's disease (PD) has been dominated by the use of dopaminergic medication, but significant unmet need remains, much of which is related to non-motor symptoms and the involvement of non-dopaminergic transmitter systems. As such, little has changed in the past decades that has led to milestone advances in therapy and significantly improved treatment paradigms and patient outcomes, particularly in relation to symptoms unresponsive to levodopa. This review has looked at how pharmacological approaches to treatment are likely to develop in the near and distant future and will focus on two areas: 1) novel non-dopaminergic pharmacological strategies to control motor symptoms; and 2) novel non-dopaminergic approaches for the treatment of non-motor symptoms. The overall objective of this review is to use a 'crystal ball' approach to the future of drug discovery in PD and move away from the more traditional dopamine-based treatments. Here, we discuss promising non-dopaminergic and 'dirty drugs' that have the potential to become new key players in the field of Parkinson's disease treatment.

Genetic architecture of Parkinson’s disease subtypes – Review of the literature

The heterogeneity of Parkinson’s disease (PD) has been recognized since its description by James Parkinson over 200 years ago. The complexity of motor and non-motor PD manifestations has led to many attempts of PD subtyping with different prognostic outcomes; however, the pathophysiological foundations of PD heterogeneity remain elusive. Genetic contributions to PD may be informative in understanding the underpinnings of PD subtypes. As such, recognizing genotype-phenotype associations may be crucial for successful gene therapy. We review the state of knowledge on the genetic architecture underlying PD subtypes, discussing the monogenic forms, as well as oligo- and polygenic risk factors associated with various PD subtypes. Based on our review, we argue for the unification of PD subtyping classifications, the dichotomy of studies on genetic factors and genetic modifiers of PD, and replication of results from previous studies.

Relationship between 123I-FP-CIT-SPECT and motor severity in drug-naive patients with Parkinson's disease

INTRODUCTION

Although functional imaging is useful for the diagnosis and pathophysiological evaluation of Parkinson's disease (PD), little is known about the relationship between functional imaging findings and PD clinical features. The objective of this study was to determine the relationship between ¹²³I-FP-CIT-SPECT findings and motor symptoms, in particular gait disturbance.

METHODS

The study included 46 drug-naive patients with early-stage PD. The specific binding ratios (SBRs) in the striatum and its subregions, namely anterior/posterior putamen and caudate nucleus, were calculated in patients who underwent ¹²³I-FP-CIT-SPECT. Motor symptoms were evaluated using the modified Hoehn and Yahr (HY) stage and the Unified Parkinson's Disease Rating Scale (UPDRS) part III. Gait disturbance was evaluated by the mean gait cycle duration and the mean gait acceleration amplitude measured with a wearable sensor.

RESULTS

The mean SBRs of the striatum and anterior putamen were significantly associated with the modified HY stage and UPDRS part III score. The mean SBR of the caudate nucleus was significantly associated with the UPDRS part III score. The mean striatal SBR was also significantly associated with the mean gait cycle duration and mean gait acceleration amplitude.

CONCLUSION

The mean striatal SBR, as determined by ¹²³I-FP-CIT-SPECT, was significantly associated with motor severity and gait severity in drug-naive patients with PD.

Executive function network's white matter alterations relate to Parkinson's disease motor phenotype

Parkinson's disease (PD) patients with postural instability and gait disorder phenotype (PIGD) are at high risk of cognitive deficits compared to those with tremor dominant phenotype (TD). Alterations of white matter (WM) integrity can occur in patients with normal cognitive functions (PD-N). However, the alterations of WM integrity related to cognitive functions in PD-N, especially in these two motor phenotypes, remain unclear. Diffusion tensor imaging (DTI) is a non-invasive neuroimaging method to evaluate WM properties and by applying DTI tractography, one can identify WM tracts connecting functional regions. Here, we 1) compared the executive function (EF) in PIGD phenotype with normal cognitive functions (PIGD-N) and TD phenotype with normal cognitive functions (TD-N) phenotypes; 2) used DTI tractography to evaluated differences in WM alterations between these two phenotypes within a task-based functional network; and 3) examined the WM integrity alterations related to EF in a whole brain network for PD-N patients regardless of phenotypes. Thirty-four idiopathic PD-N patients were classified into two groups based on phenotypes: TD-N and PIGD-N, using an algorithm based on UPDRS part III. Neuropsychological tests were used to evaluate patients' EF, including the Trail making test part A and B, the Stroop color naming, the Stroop word naming, the Stroop color-word interference task, as well as the FAS verbal fluency task and the animal category fluency tasks. DTI measures were calculated among WM regions associated with the verbal fluency network defined from previous task fMRI studies and compared between PIGD-N and TD-N groups. In addition, the relationship of DTI measures and verbal fluency scores were evaluated for our full cohort of PD-N patients within the whole brain network. These values were also correlated with the scores of the FAS verbal fluency task. Only the FAS verbal fluency test showed significant group differences, having lower scores in PIGD-N when compared to TD-N phenotype (p < 0.05). Compared to the TD-N, PIGD-N group exhibited significantly higher MD and RD in the tracts connecting the left superior temporal gyrus and left insula, and those connecting the right pars opercularis and right insula. Moreover, compared to TD-N, PIGD-N group had significantly higher RD in the tracts connecting right pars opercularis and right pars triangularis, and the tracts connecting right inferior temporal gyrus and right middle temporal gyrus. For the entire PD-N cohort, FAS verbal fluency scores positively correlated with MD in the superior longitudinal fasciculus (SLF). This study confirmed that PIGD-N phenotype has more deficits in verbal fluency task than TD-N phenotype. Additionally, our findings suggest: (1) PIGD-N shows more microstructural changes related to FAS verbal fluency task when compared to TD-N phenotype; (2) SLF plays an important role in FAS verbal fluency task in PD-N patients regardless of motor phenotypes.

Therapy of Parkinson's Disease Subtypes

Early descriptions of subtypes of Parkinson's disease (PD) are dominated by the approach of predetermined groups. Experts defined, from clinical observation, groups based on clinical or demographic features that appeared to divide PD into clinically distinct subsets. Common bases on which to define subtypes have been motor phenotype (tremor dominant vs akinetic-rigid or postural instability gait disorder types), age, nonmotor dominant symptoms, and genetic forms. Recently, data-driven approaches have been used to define PD subtypes, taking an unbiased statistical approach to the identification of PD subgroups. The vast majority of data-driven subtyping has been done based on clinical features. Biomarker-based subtyping is an emerging but still quite undeveloped field. Not all of the subtyping methods have established therapeutic implications. This may not be surprising given that they were born largely from clinical observations of phenotype and not in observations regarding treatment response or biological hypotheses. The next frontier for subtypes research as it applies to personalized medicine in PD is the development of genotype-specific therapies. Therapies for GBA-PD and LRRK2-PD are already under development. This review discusses each of the major subtyping systems/methods in terms of its applicability to therapy in PD, and the opportunities and challenges designing clinical trials to develop the evidence base for personalized medicine based on subtypes.

The effects of dual-task in patients with Parkinson's disease performing cognitive-motor paradigms

Patients with Parkinson's disease (PD) exhibit impaired dual-task (DT) performance. A recent meta-analysis confirmed that dual tasking severely affects walking performance in PD patients. However, one report indicated that a cycling DT paradigm has facilitative effects on cognition. We investigated the effects of dual tasking by using walking and cycling as motor tasks and revealed the clinical determinants associated with DT performance. Twenty-seven eligible participants were enrolled for clinical, cognitive-walking, and cognitive-cycling DT paradigm investigations. The mean age and age at onset of the patients were 59.87 ± 6.3 and 53.11 ± 8.4 years, respectively. Both the off- and on-state akinesia subscores were worse on the more-affected side than on the less-affected side. However, the DT effects on the cycling and gait outcomes on both the more-affected and the less-affected side showed no significant differences. The DT effect on the two motor tasks and cognitive performance during a concurrent walking task declined. Nevertheless, the DT effect on cognition improved during cycling. The present study also revealed that the levodopa equivalent daily dosage was highly associated with cognitive-cycling performance and that the akinesia subscore was the most relevant factor that contributed to cognitive-walking performance. In conclusion, DT facilitation or interference might be mediated by the type of motor task applied. The cognitive-cycling DT paradigm had a facilitative effect on cognition. Cycling exercise may diminish motor dysfunction has been investigated. We suggest that cognitive-cycling DT training is a potential adjuvant therapeutic strategy for patients with PD to promote motor and cognitive functions.

Investigation of Nonmotor Symptoms in First-Degree Relatives of Patients with Different Clinical Types of Parkinson's Disease

Background

Nonmotor symptoms (NMS) are prodromal characteristics of Parkinson's disease (PD). The first-degree relatives (FDR) of PD patients had a higher risk of PD and also had more NMS.

Objective

To delineate NMS in FDR of patients with different clinical types of PD.

Methods

A total of 98 PD probands were recruited; 256 siblings of them were enrolled in the FDR group. Various scales were used to assess NMS, including depression, anxiety, cognitive impairment, insomnia, constipation, excessive daytime sleepiness, rapid eye movement sleep behavior disorder (RBD), and restless legs syndrome (RLS). The incidences of NMS were further compared between the FDR groups of PD with different types.

Results

The FDR of early-onset PD (EOP) showed a higher incidence of moderate to severe depression (OR = 4.08; 95% CI: 1.12–14.92; P=0.033), anxiety (OR = 4.22; 95% CI: 1.87–9.52; P=0.001), and excessive daytime sleepiness (OR = 3.40; 95% CI: 1.00–11.48; P=0.049) than the FDR of late-onset PD (LOP). It was also found that RBD (OR = 11.65; 95% CI: 3.82–35.54; P < 0.001), constipation (OR = 4.94; 95% CI: 1.85–13.21; P=0.001), sleep disorders (OR = 4.51; 95% CI: 1.73–11.78; P=0.002), cognitive impairment (OR = 3.55; 95% CI: 1.62–7.77; P=0.002), and anxiety (OR = 2.49; 95% CI: 1.32–4.71; P=0.005) were more frequent in FDR of tremor-dominant PD (TDP) than in FDR of non-tremor-dominant PD (NTDP).

Conclusions

The siblings of patients with EOP and TDP have more NMS, presuming that they have a higher risk in the PD prodromal stage. Whether they have a greater possibility to progress into PD requires further investigation.

Comparison of clinical features among Parkinson's disease subtypes: A large retrospective study in a single center

INTRODUCTION

Tremor dominant (TD), postural instability/gait difficulty (PIGD), and akinetic-rigid (AR) subtypes are widely used in classifying patients with Parkinson's disease (PD).

METHODS

We compared clinical characteristics between PD subtypes in a large retrospective cohort. Between 1998 and 2016, we included a total of 1003 patients with PD in this retrospective study. Six hundred ninety-four patients had more than one visit. Data were collected regarding motor/non-motor symptoms at the initial/final visits. Based on the prominent symptom at the initial visit, we classified patients into one of the four subtypes: TD, AR, gait difficulty, and mixed. Rapid progression was defined by emergence of falls, dementia, or dependency within 5years after onset.

RESULTS

TD was the most prevalent subtype (44%), followed by AR (29%), mixed (18%), and gait difficulty (9%). Rapid progression was observed more frequently in gait difficulty compared to AR (OR: 3.59 P<0.001). Hallucinations at the final visit were more likely to occur in AR (OR: 2.36, P=0.005) and mixed (OR: 3.28, P<0.001) compared to TD.

CONCLUSIONS

Our findings provide support for a distinction of four different PD subtypes: TD, AR, gait difficulty, and mixed. The gait difficulty subtype was distinguishable from the AR subtype.

Familial aggregation of Parkinson's disease may affect progression of motor symptoms and dementia

BACKGROUND

Familial aggregation has been described in PD of both early and late onset, but has not been studied in a true population-based sample. Moreover, little is known about its association with disease progression and endophenotypes.

OBJECTIVES

The objectives of this work were to determine familial aggregation of idiopathic PD in a population-based cohort and study the association with clinical endophenotypes and disease progression.

METHODS

We examined family history data from the Norwegian ParkWest study, a well-characterized, population-based cohort of incident PD patients and age-matched healthy controls. Family data were collected at baseline with a simplified questionnaire (192 cases and 193 controls) and after 3 years of longitudinal follow-up using an extended questionnaire (172 cases and 171 controls).

RESULTS

Compared to the controls, the PD patients had an increased relative risk of having a first-degree relative with PD when using the extended questionnaire (relative risk = 1.988; P = 0.036), but not when using the simplified questionnaire (relative risk = 1.453; P = 0.224). There was no significant difference in age of onset or motor subtype (P = 0.801). However, cases with a family history of PD had reduced progression over 7 years as measured by UPDRS II (P = 0.008) and smaller rate of decrease of MMSE (P = 0.046).

CONCLUSIONS

Our findings confirm familial aggregation in a population-based cohort of idiopathic PD. Moreover, we show that positive family history of PD in patients is associated with a slower progression of PD symptoms and cognitive decline. © 2016 International Parkinson and Movement Disorder Society.

Characteristics of subthalamic oscillatory activity in parkinsonian akinetic-rigid type and mixed type

OBJECTIVE

To explore neurons with β oscillatory activity in the subthalamic nucleus (STN) in relation to parkinsonian motor signs.

METHODS

We studied 27 patients with Parkinson's disease (PD) who underwent electrode implantation for STN deep brain stimulation. Thirteen patients were classified as akinetic-rigid (AR) type and 14 patients were classified as mixed type. Microelectrode recording was performed in the STN and the electromyogram (EMG) was simultaneously recorded. Single-unit and spectral analyses were performed. Coherence analysis was used to explore the relationship between β oscillatory activity and EMG activity. Unpaired t-test and chi-square were used to compare the differences between the two PD types.

RESULTS

Of 130 neurons identified in the AR type, 43.8% were β oscillatory neurons (mean: 21.3 ± 6.87 Hz, βFB) and 0.8% were tremor frequency oscillatory neurons (4-6 Hz, TFB). Of 102 neurons identified in the mixed type, 19.6% were β oscillatory neurons and 26.5% were TFB oscillatory neurons. There was a significant difference in proportion of neurons with βFB and TFB oscillations between the two PD groups. Additionally, 12% of the βFB oscillatory neurons were coherent with limb EMG of the AR type, but there was no coherence in the mixed type. Most oscillatory neurons were localized in the dorsal portion of the STN.

CONCLUSION

The STN βFB oscillatory neurons correlate with parkinsonian rigidity-bradykinesia. The high proportion of βFB oscillatory neurons found in the AR type of PD is indirect evidence for their importance in generating motor impairment.

Change in plasma levels of amino acid neurotransmitters and its correlation with clinical heterogeneity in early Parkinson's disease patients

BACKGROUND

The correlation between plasma amino acid (AA) neurotransmitters and clinical heterogeneity in early patients with Parkinson's disease (PD) is still poorly understood.

AIMS

To examine the plasma levels of AA neurotransmitters in early patients with PD and to evaluate their correlation with PD subtypes.

METHODS

Based on the predominant symptoms, fifty-one patients with PD were enrolled and divided into four subgroups: (1) akinetic-rigid type (ART), (2) tremor-dominant type (TDT), (3) postural instability/gait difficulty type (PIGD), and (4) mixed type (MT). Plasma levels of AA were measured by HPLC-RF, and their potential diagnostic practicality and their association with PD subtypes were evaluated by the receiver operating characteristic (ROC) and correlation analysis, respectively.

RESULTS

Patients with PD exhibited markedly lower levels of Asp, Glu, Tau, L-ser, and lower values of Glu/GABA ratio than healthy controls. The ROC analysis revealed their high sensitivity (77.1-87.5%) and specificity (58.8-88.2%). Furthermore, the glutamic acid (Glu), γ-aminobutyric acid (GABA) level in the PIGD subtype was increased as compared with other subtypes and was negatively correlated with the ART/PIGD ratio.

CONCLUSION

The decrease in plasma Asp, Glu, Tau, L-ser levels, and the value of Glu/GABA ratio may be helpful for early PD diagnosis. The elevated GABA level may be the biochemical basis for the specific symptoms of PIGD PD.

Parkinson disease: associated disorders in the Norwegian population based incident ParkWest study

Parkinson's disease (PD) may be associated with a number of different diseases due to common risk factors or overlapping symptomatology. We have asked for possible associated disorders in a Norwegian population of incident PD patients and controls, the Norwegian ParkWest study. The patients were diagnosed according to the Gelb criteria. 212 incident PD patients and 175 age and gender matched controls were included. PD patients and controls were asked for information on earlier medical history and family history. PD patients had a higher frequency of self-reported symptoms of depression (p = 0.003) and anxiety disorders (p = 0.004) before baseline. They tended to have a higher frequency of diabetes (p = 0.09) and had a higher frequency of prior stroke or TIA (p = 0.004).

Nigral iron deposition occurs across motor phenotypes of Parkinson's disease

BACKGROUND AND PURPOSE

  To investigate whether brain iron deposition correlates with motor phenotypic expressions of Parkinson's disease.

METHODS

  We subtyped patients with Parkinson's disease according to their main motor symptoms (tremor, rigidity/bradykinesia) into three subgroups: tremor-dominant subgroup, akinetic/rigid-dominant subgroup, or mixed subgroup. The iron levels in bilateral substantia nigra, globus pallidus, putamen, the head of caudate, and red nucleus of 87 patients and 50 control subjects were assayed by measuring phase values using susceptibility-weighted phase imaging in a 3-tesla magnetic resonance system. The serum ceruloplasmin levels of all subjects were determined.

RESULTS

  The bilateral average phase values of the substantia nigra and all other brain regions examined did not correlate with the main motor symptoms of Parkinson's disease in the total patient group or when patients were grouped according to serum ceruloplasmin levels. Significant correlations between serum ceruloplasmin levels and nigral bilateral average phase values were observed in the tremor and akinetic/rigid-dominant subgroups. Analysis of patients without prior dopaminergic medication exhibited similar results. Increased nigral iron content correlated with disease severity as assayed by the Unified Parkinson's Disease Rating Scale motor scores in the PD(AR) subgroup.

CONCLUSIONS

  These findings suggest that nigral iron deposition, correlating with decreased serum ceruloplasmin levels, is a risk factor in Parkinson's disease across multiple motor phenotypic expressions.

Substantia nigra echogenicity in Parkinson's disease: relation to serum iron and C-reactive protein

In Parkinson's disease (PD), substantia nigra hyperechogenicity (SN-h) has been related to both, local iron accumulation and microglia activation. We analysed its relationship in PD patients with serum iron (n = 31) and C-reactive protein (CRP; n = 193). SN-h correlated with lower CRP and iron levels. Also, patients with a first-degree relative with PD had lower iron levels. Microglia activation, if reflected by SN-h, may be therefore unrelated to serum CRP. Findings support the idea that SN-h indicates inherited alteration of iron metabolism.

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.

Cognition, language, and clinical pathological features of non-Alzheimer's dementias: an overview

There are many distinct forms of dementia whose pharmacological and behavioral management differ. Differential diagnosis among the dementia variants currently relies upon a weighted combination of genetic and protein biomarkers, neuroanatomical integrity, and behavior. Diagnostic specificity is complicated by a high degree of overlap in the initial presenting symptoms across dementia subtypes. For this reason, reliable markers are of considerable diagnostic value. Communication disorders have proven to be among the strongest predictors for discriminating among dementia subtypes. As such, speech-language pathologists may be poised to make an increasingly visible contribution to dementia diagnosis and its ongoing management. The value and durability of this potential contribution, however, demands an improved discipline-wide knowledge base about the unique features associated with different dementia variants. To this end we provide an overview of cognition, language, and clinical pathological features of four of the most common non-Alzheimer's dementias: frontotemporal dementia, vascular dementia, Lewy body disease dementia, and Parkinson's disease dementia.

LEARNING OUTCOMES

Readers will learn characteristics and distinguishing features of several non-Alzheimer's dementias, including Parkinson's disease dementia, frontotemporal dementia, vascular dementia, and Lewy body dementia. Readers will also learn to distinguish between several variants of frontotemporal dementia. Finally, readers will gain knowledge of the term primary progressive aphasia as it relates to the aforementioned dementia etiologies.

Adenosine antagonists reverse the cataleptic effects of haloperidol: implications for the treatment of Parkinson's disease

The effects of adenosine antagonists were compared in two rodent models of Parkinsonian symptoms. In the first experiment the dopamine D2 antagonist, haloperidol, was used to induce catalepsy. It was found that treatment with the non-selective adenosine antagonist caffeine significantly reduced catalepsy at each dose. Treatment with the selective A1 antagonist CPT also produced a significant reduction in catalepsy, as did treatment with the selective A2A antagonist SCH58261. In the second experiment haloperidol was used to suppress locomotor activity in an open field test. Treatment with caffeine significantly increased locomotion reduced by haloperidol, but not at all doses tested. Treatment with CPT also increased haloperidol-suppressed locomotor activity in dose-dependent manner. Surprisingly, treatment with SCH58261 did not significantly increase locomotor activity in animals treated with haloperidol at any dose tested. While some of these results were unexpected, the overall pattern suggests that adenosine antagonists would be useful as therapies for Parkinsonian patients as they appear to increase movement. The results also suggest that in acute timelines A1 antagonists may be more beneficial than previously supposed.

Familial aggregation of Parkinson's disease: a meta-analysis

We sought to determine the relative risk (RR) of Parkinson's disease (PD) for having a first-degree relative with PD versus having no first-degree relative with PD. Studies of familial aggregation of PD were identified by searching Medline and other sources. From each study, RRs were extracted or calculated based on the published data. Studies were categorized according to methodological characteristics, as well as by first-degree relationship type and age at PD onset restrictions. Meta-analyses and meta-regressions were based on random effect models. Twenty-nine studies of familial aggregation of PD were identified with results for first-degree relatives. The best estimate of the RR of PD for having a first-degree relative with PD was 2.9 (95% CI: 2.2, 3.8; P = 2.2 E-14), based on the studies with the most rigorous methods. The RR for sibling pairs was 4.4 (95% CI: 3.1, 6.1; P < 1.0 E-30), while for child-parent pairs it was 2.7 (95% CI: 2.0, 3.7; P = 3.6 E-10). The RR for early onset PD was 4.7 (95% CI: 3.2, 6.8; P = 6.7 E-16), while for late onset PD it was 2.7 (95% CI: 1.9, 3.9; P = 1.8 E-8). Inclusion of methodologically less rigorous investigations tended to increase the RR estimates. Summary RRs were clearly elevated above one for all study methods, all first-degree relationship types, and all age at onset categories. Familial aggregation of PD is strong and unlikely to be due to chance or to deficiencies in study methodology.

A whole-brain analysis in de novo Parkinson disease

BACKGROUND AND PURPOSE

Widespread cerebral changes are observed in advanced stages of Parkinson disease (PD), suggesting that PD is a multisystem disorder. We investigated with MR imaging whether global brain changes are present in early clinical stages of PD and correlated the findings with the type of clinical presentation.

MATERIALS AND METHODS

T1-weighted images and mean diffusivity and fractional anisotropy (FA) maps calculated from diffusion tensor imaging (DTI) were obtained in 27 patients with de novo drug-naïve PD, who were classified according to the clinical features in tremor-dominant type (n = 13), akinetic-rigid type (n = 11), and mixed type (n = 3). Sixteen healthy subjects provided control data. With SIENAX software, total brain, gray matter (GM), and white matter (WM) volumes were computed from T1-weighted images, whereas brain histograms were obtained from mean diffusivity and FA maps.

RESULTS

Total brain, GM and WM volumes were not significantly different in patients as a whole or subgroups and controls. As compared with controls, patients with PD as a whole and patients with the akinetic-rigid type showed an increase (P

CONCLUSIONS

In patients with de novo PD, there is an increase of FA values, more pronounced in patients with the akinetic-rigid type, probably reflecting diffuse subtle GM loss. This is in line with the hypothesis that widespread neurodegeneration is already present at the time of the clinical onset.

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Key Words Collapse

MESH Headings

• Brain/pathology
• Diffusion Magnetic Resonance Imaging
• Female
• Humans
• Male
• Middle Aged
• Organ Size
• Parkinson Disease/diagnosis
• Parkinson Disease/pathology

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Grants Collapse

Affiliation(s)

C Tessa Radiology Unit, Versilia Hospital, Lido di Camaiore, Lucca, Italy
M Giannelli
R Della Nave
C Lucetti
C Berti
A Ginestroni
U Bonuccelli
M Mascalchi

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Relation between subtype of Parkinson’s disease and REM sleep behavior disorder

OBJECTIVES

Rapid eye movement (REM) sleep behavior disorder (RBD) is frequently found in Parkinson's disease (PD). PD has been classified in different subtypes and it is unknown if RBD occurs more often in one particular subtype.

METHODS

Determination of PD subtype by review of clinical history in consecutively diagnosed PD patients with RBD.

RESULTS

We determined the subtype (tremor- or non-tremor-predominant) of PD and the age at onset of parkinsonism and RBD by review of clinical history. PD patients with RBD had mostly the non-tremor-predominant subtype. RBD preceded parkinsonism only when parkinsonism started after the age of 50 years.

CONCLUSIONS

A different pattern of neurodegeneration in non-tremor-predominant PD may explain its preferential association with RBD. The neurodegeneration that causes PD might be insufficient to produce RBD before the sixth decade.

Midbrain transcranial sonography in Korean patients with Parkinson's disease

Transcranial sonography (TCS) is potentially useful for the diagnosis of Parkinson's disease (PD). However, studies on TCS have so far been restricted to European populations. To investigate the efficacy of TCS in Korean PD patients and its correlation with the clinical features, we carried out midbrain TCS in 43 PD patients and 35 normal controls and evaluated the area of the substantia nigra (SN) hyperechogenicity and its ratio to the area of the whole midbrain. In 16 subjects (21%), TCS was unsuccessful due to insufficient acoustic temporal bone windows. The mean area of bilateral SN hyperechogenicity and its ratio to the midbrain area were greater in the PD patients than that in the controls (P < 0.01). In the PD patients, the area of SN hyperechogenicity and its ratio to the individual midbrain area were moderately correlated with the PD duration (r = 0.526 and 0.536, P = 0.01, respectively) but not with the age, UPDRS motor scores or H-Y stage. There was no difference in the SN hyperechogenicity between the tremor-dominant, akinetic-rigid, and mixed-type PD patients. In conclusion, midbrain TCS is an effective diagnostic tool for detecting PD in the Korean population. However, it does not reflect the severity or phenotypes of parkinsonism.

Myocardial sympathetic degeneration correlates with clinical phenotype of Parkinson's disease

In idiopathic Parkinson's disease (PD), different clinical subtypes are distinguished due to predominant motor symptoms: a tremor-dominant type (TDT), an akinetic rigid type (ART), and a mixed type (MT). We compared myocardial sympathetic innervation, measured by MIBG scintigraphy, in different subtypes of PD at early and advanced stages of PD. We applied MIBG scintigraphy in 102 patients with PD. About 57 patients were at Hoehn and Yahr (H&Y) stage 1, 22 at H&Y stage 2, and 23 at H&Y stages 3 and 4. For quantification of myocardial MIBG uptake, the heart-to-mediastinum (H/M) count-ratio was calculated. At all H&Y stages, myocardial MIBG uptake was significantly higher in TDT patients than in ART or MT patients (P < 0.05; ANOVA). Furthermore, at each H&Y stage, myocardial MIBG uptake correlated significantly with severity of hypokinesia (P < 0.05; Spearman's correlation) and rigidity (P < 0.05), but not with severity of resting or postural tremor. The significant correlation between myocardial sympathetic degeneration and severity of hypokinesia and rigidity suggests that myocardial sympathetic degeneration and hypokinetic-rigid symptoms develop in a closely coupled manner in early as well as advanced PD. No such correlation can be found between myocardial sympathetic degeneration and parkinsonian tremor.

Transcranial brain sonography findings in clinical subgroups of idiopathic Parkinson's disease

To investigate whether transcranial brain sonography (TCS) discriminates different courses of idiopathic Parkinson's disease (PD), 101 patients with clinically definite PD were studied. In four patients, TCS was not possible due to insufficient acoustic temporal bone windows. Substantia nigra (SN) hyperechogenicity was found in 96% of assessable patients. Larger SN echogenic size correlated with younger age at PD onset (Spearman correlation, r = -0.383; P < 0.001), but not with age, PD duration, or severity. Marked bilateral SN hyperechogenicity indicated early-onset rather than late-onset PD, and akinetic-rigid (AR) or mixed-type (MX) PD rather than tremor-dominant PD. SN echogenic sizes were larger contralateral to the clinically more affected side in AR PD and MX PD patients. Reduced echogenicity of brainstem raphe was associated with depression (RR = 1.61; 95% CI = 1.05-2.46; P = 0.044) but not with other clinical features. Caudate nucleus hyperechogenicity was, independently from PD duration, related to drug-induced psychosis (RR = 2.40; CI = 1.36-4.22; P = 0.001), but not to motor fluctuations. Lenticular nucleus hyperechogenicity indicated AR PD rather than tremor-dominant PD (RR = 1.44; CI = 1.11-1.86; P = 0.040). Frontal horn dilatation > 15.4 mm (mean of bilateral measurements) indicated increased risk of dementia (RR = 4.11; CI = 1.51-11.2; P = 0.001). We conclude that TCS displays characteristic changes of deep brain structures in different clinical manifestations of PD.

Parkinson's disease and family history

The study of family history in Parkinson's disease (PD) has resulted in considerable debate over the role of genetic factors in the development of PD. Despite this, family history is consistently identified as an independent risk factor for PD. A multifactorial disease process in which genetic, environmental and lifestyle factors culminate in overall risk seems most likely. This article reviews existing studies of familial aggregation in PD. Recent insights into rare genetic causes of PD have affirmed the importance of ongoing family history research. Future efforts should emphasise well-designed family studies with extensive, non-exclusive phenotyping and ideally long-term follow-up.

Complex segregation analysis of Parkinson's disease: The Mayo Clinic Family Study

OBJECTIVE

To conduct complex segregation analyses of Parkinson's disease (PD).

METHODS

Data on the familial aggregation of PD remain conflicting. We conducted a historical cohort study of 1,234 relatives of 162 patients with PD representative of people of Olmsted County, MN, and of 3,009 relatives of 411 patients with PD referred to the Mayo Clinic. Relatives were interviewed and screened for parkinsonism either directly or through a proxy, those who screened positive were examined, or a copy of their medical record was obtained to confirm the diagnosis. For subjects who resided in Olmsted County, additional information was obtained from the archives of the Olmsted County Historical Society and from a records-linkage system.

RESULTS

Thirty-two relatives of population-based probands and 69 relatives of referral patients developed PD (101 in total). Combining population-based and referral samples, the model that best explained the familial clustering of PD overall was a major gene with additive effect on the penetrance. This model predicted an average decrease in age at onset of PD of approximately 18 years for each copy of the putative high-risk allele. The best fitting model for younger onset PD (age <or= 59 years) was an autosomal recessive model. The best fitting models for older onset PD (age > 59 years) were a recessive or an additive model.

INTERPRETATION

The familial aggregation of PD may be explained in part by a major gene with additive effect on the penetrance.

Striatal FP-CIT uptake differs in the subtypes of early Parkinson's disease

In idiopathic Parkinson's disease (PD), a tremor-dominant type (TDT), an akinetic-rigid type (ART), and a mixed type (MT) are distinguished. We compared cerebral [I-123]FP-CIT SPECT in the PD subtypes (67 patients Hoehn and Yahr stage 1:26 with ART, 19 with MT, 22 with TDT). We measured the ratios putamen/occipital lobe binding and caudate nucleus/occipital lobe binding. Parkinsonian motor symptoms were quantified by UPDRS motor scale. In both putamen and caudate nucleus contralateral to the clinically affected body side TDT patients showed a significantly higher FP-CIT uptake than ART or MT patients (ANOVA; p<0.01). Contralateral putamen and caudate nucleus FP-CIT uptake correlated significantly with severity of rigidity (p<0.01) and hypokinesia (p<0.01) but not with severity of resting or postural tremor (p>0.05). The missing correlation between striatal FP-CIT uptake and tremor suggests, that further systems besides the nigrostriatal dopaminergic system may contribute to generation of parkinsonian tremor.

Clinical characteristics in early Parkinson's disease in a central California population-based study

There is considerable variation in the phenotypic appearance of individuals with idiopathic Parkinson's disease (PD), which may translate into differences in disease progression in addition to underlying disease etiology. In this publication, we report on the demographic and clinical characteristics of 162 individuals diagnosed with clinically probable PD from January 1998 to June 2003 who resided in predominantly rural communities in central California. The majority of the subjects were Caucasian, male, and between 60 and 79 years of age. The akinetic-rigid and tremor-dominant subtypes were more common than the mixed subtype. The majority of subjects displayed motor signs of rigidity (92.0%), bradykinesia (95.7%), and gait problems (87.0%), whereas less than half (43.3%) of the subjects displayed a tremor. Three fourths of patients received a Hoehn and Yahr Scale score of Stage 2 or higher. One third of the patients were treated with levodopa, and patients under 60 years of age were more likely to be treated with dopamine agonists. Within 3 years after first diagnosis, 13% of subjects showed some signs of depression and 17% of subjects met criteria for mild dementia. Among our subjects, 17.3% reported a family history of PD in first- or second-degree relatives,15.4% a family history of essential tremor, and 14.2% of Alzheimer's disease. This study represents the most extensive phenotypic description of rural U.S. residents in the initial stages of PD who were recruited in a population-based manner; future follow-up may provide valuable information regarding the prognostic indication of these symptoms/signs and improve our understanding of the underlying etiology of PD.