Rapid Eye Movement Sleep Behavior Disorder in Parkinson's Disease: A Survey-Based Study

OBJECTIVE

To characterize Parkinson's disease (PD) symptoms based on the presence, onset time, and severity of rapid eye movement sleep behavior disorder (RBD) and their association with impulse control disorders (ICD).

BACKGROUND

RBD is a frequent non-motor symptom in PD, usually described as prodromal. The severity of RBD according to the start time and its relationship with ICD in PD needs further clarification.

METHODS

A survey-based study was performed to determine the presence of RBD symptoms, their severity, and the temporal relationship with the PD onset. The survey included RBD1Q, the Mayo Sleep, and the RBDQ-HK questionnaires and questions about clinical characteristics, including ICD. Only PD patients with care partners spending night hours in the same room were included.

RESULTS

410 PD patients were included: 206 with RBD (50.2%) and 204 non-RBD (49.8%). The PD-RBD patients were younger and their daily levodopa dose was higher than the non-RBD group. Most of these patients developed RBD symptoms after the onset of clinical PD were younger at motor symptom onset and had higher scores in the hallucinations and psychosis subsection of MDS-UPDRS-I. RBD group had a more severe non-motor phenotype, including more ICD than those without RBD, mainly due to higher compulsive eating.

CONCLUSIONS

In our study, most patients recognized RBD symptoms after the onset of the PD motor symptoms and the clinical features of PD with and without RBD were distinctive, supporting the hypothesis that PD-RBD might represent a variant pattern of neurodegeneration.

Caregiving concerns and clinical characteristics across neurodegenerative and cerebrovascular disorders in the Ontario neurodegenerative disease research initiative

OBJECTIVES

Caregiving burdens are a substantial concern in the clinical care of persons with neurodegenerative disorders. In the Ontario Neurodegenerative Disease Research Initiative, we used the Zarit's Burden Interview (ZBI) to examine: (1) the types of burdens captured by the ZBI in a cross-disorder sample of neurodegenerative conditions (2) whether there are categorical or disorder-specific effects on caregiving burdens, and (3) which demographic, clinical, and cognitive measures are related to burden(s) in neurodegenerative disorders?

METHODS/DESIGN

N = 504 participants and their study partners (e.g., family, friends) across: Alzheimer's disease/mild cognitive impairment (AD/MCI; n = 120), Parkinson's disease (PD; n = 136), amyotrophic lateral sclerosis (ALS; n = 38), frontotemporal dementia (FTD; n = 53), and cerebrovascular disease (CVD; n = 157). Study partners provided information about themselves, and information about the clinical participants (e.g., activities of daily living (ADL)). We used Correspondence Analysis to identify types of caregiving concerns in the ZBI. We then identified relationships between those concerns and demographic and clinical measures, and a cognitive battery.

RESULTS

We found three components in the ZBI. The first was "overall burden" and was (1) strongly related to increased neuropsychiatric symptoms (NPI severity r = 0.586, NPI distress r = 0.587) and decreased independence in ADL (instrumental ADLs r = -0.566, basic ADLs r = -0.43), (2) moderately related to cognition (MoCA r = -0.268), and (3) showed little-to-no differences between disorders. The second and third components together showed four types of caregiving concerns: current care of the person with the neurodegenerative disease, future care of the person with the neurodegenerative disease, personal concerns of study partners, and social concerns of study partners.

CONCLUSIONS

Our results suggest that the experience of caregiving in neurodegenerative and cerebrovascular diseases is individualized and is not defined by diagnostic categories. Our findings highlight the importance of targeting ADL and neuropsychiatric symptoms with caregiver-personalized solutions.

Protocol of a randomised delayed-start double-blind placebo-controlled multi-centre trial for Levodopa in EArly Parkinson's disease: the LEAP-study

Background

The aim of this study is to investigate if early treatment with levodopa has a beneficial disease modifying effect on Parkinson’s disease (PD) symptoms and functional health, improves the ability to (maintain) work, and reduces the use of (informal) care, caregiver burden, and costs. Additionally, cost-effectiveness and cost-utility of early levodopa treatment will be assessed.

Methods

To differentiate between the direct symptomatic effects and possible disease modifying effects of levodopa, we use a randomised delayed-start double-blind placebo-controlled multi-centre trial design. Patients with early stage PD whose functional health does not yet necessitate initiation of PD-medication will be randomised to either 40 weeks of treatment with levodopa/carbidopa 100/25 mg TID including 2 weeks of dose escalation or to 40 weeks placebo TID. Subsequently, all patients receive levodopa/carbidopa 100/25 mg TID for 40 weeks. There are 8 assessments: at baseline and at 4, 22, 40, 44, 56, 68, and 80 weeks. The primary outcome measure is the difference in the mean total Unified Parkinson’s Disease Rating Scale scores between the early- and delayed-start groups at 80 weeks. Secondary outcome measures are rate of progression, the AMC Linear Disability Score, side effects, perceived quality of life with the Parkinson’s Disease Questionnaire-39, the European Quality of Life-5 Dimensions (EQ-5D), ability to (maintain) work, the use of (informal) care, caregiver burden, and costs. 446 newly diagnosed PD patients without impaired functional health need to be recruited in order to detect a minimal clinical relevant difference of 4 points on the total UPDRS at 80 weeks.

Discussion

The LEAP-study will provide insights into the possible disease modifying effects of early levodopa.

Trial registration

ISRCTN30518857, EudraCT number 2011-000678-72

Post-mortem assessment of the short and long-term effects of the trophic factor neurturin in patients with α-synucleinopathies

Substantial interest persists for developing neurotrophic factors to treat neurodegenerative diseases. At the same time, significant progress has been made in implementing gene therapy as a means to provide long-term expression of bioactive neurotrophic factors to targeted sites in the brain. Nonetheless, to date, no double-blind clinical trial has achieved positive results on its primary endpoint despite robust benefits achieved in animal models. A major issue with advancing the field is the paucity of information regarding the expression and effects of neurotrophic factors in human neurodegenerative brain, relative to the well-characterized responses in animal models. To help fill this information void, we examined post-mortem brain tissue from four patients with nigrostriatal degeneration who had participated in clinical trials testing gene delivery of neurturin to the putamen of patients. Each had died of unrelated causes ranging from 1.5-to-3-months (2 Parkinson's disease patients), to 4+-years (1 Parkinson's disease and 1 multiple-system atrophy-parkinsonian type patient) following gene therapy. Quantitative and immunohistochemical evaluation of neurturin, alpha-synuclein, tyrosine hydroxylase (TH) and an oligodendroglia marker (Olig 2) were performed in each brain. Comparable volumes-of-expression of neurturin were seen in the putamen in all cases (~15-22%; mean=18.5%). TH-signal in the putamen was extremely sparse in the shorter-term cases. A 6-fold increase was seen in longer-term cases, but was far less than achieved in animal models of nigrostriatal degeneration with similar or even far less NRTN exposure. Less than 1% of substantia nigra (SN) neurons stained for neurturin in the shorter-term cases. A 15-fold increase was seen in the longer-term cases, but neurturin was still only detected in ~5% of nigral cells. These data provide unique insight into the functional status of advanced, chronic nigrostriatal degeneration in human brain and the response of these neurons to neurotrophic factor stimulation. They demonstrate mild but persistent expression of gene-mediated neurturin over 4-years, with an apparent, time-related amplification of its transport and biological effects, albeit quite weak, and provide unique information to help plan and design future trials.

Pallidal Deep Brain Stimulation in Cervical Dystonia: Clinical Outcome in Four Cases

Objective:

Report on the clinical results following bilateral globus pallidus interna deep brain stimulation in four patients (one female and three males) with severe cervical dystonia, mean age 48 years (range 37-67).

Methods:

All four patients had failed extensive medical and botulinum toxin treatment. The mean duration of the disease was nine years (range 4-15 years). Patients were assessed pre and postoperatively using the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS). Preoperatively, the mean TWSTRS total score was 43.2 (range 28-60.5). Posteroventral pallidal deep brain stimulators were inserted using MRI and microelectrode recording guidance. Last follow-up was 15 months for the four patients.

Results:

Mean reduction in the TWSTRS total scores at last follow- up was 73% (range 61- 85%). Improvement in pain occurred soon after deep brain stimulation surgery. Motor improvement was delayed and prolonged over several months. Frequent adjustment in the stimulation parameters was necessary in the first three months.

Conclusion:

Bilateral pallidal stimulation is effective in management of selected cases of intractable cervical dystonia.

Neuronal degeneration, synaptic defects, and behavioral abnormalities in tau₄₅₋₂₃₀ transgenic mice

The complement of mechanisms underlying tau pathology in neurodegenerative disorders has yet to be elucidated. Among these mechanisms, abnormal tau phosphorylation has received the most attention because neurofibrillary tangles present in Alzheimer's disease (AD) and related disorders known as tauopathies are composed of hyperphosphorylated forms of this microtubule-associated protein. More recently, we showed that calpain-mediated cleavage leading to the generation of the 17kDa tau₄₅₋₂₃₀ fragment is a conserved mechanism in these diseases. To obtain insights into the role of this fragment in neurodegeneration, we generated transgenic mice that express tau₄₅₋₂₃₀ and characterized their phenotype. Our results showed a significant increase in cell death in the hippocampal pyramidal cell layer of transgenic tau₄₅₋₂₃₀ mice when compared to wild-type controls. In addition, significant synapse loss was detected as early as six months after birth in transgenic hippocampal neurons. These synaptic changes were accompanied by alterations in the expression of the N-methyl-d-aspartate glutamate (NMDA) receptor subunits. Furthermore, functional abnormalities were detected in the transgenic mice using Morris Water Maze and fear conditioning tests. These results suggest that the accumulation of tau₄₅₋₂₃₀ is responsible, at least in part, for neuronal degeneration and some behavioral changes in AD and other tauopathies. Collectively, these data provide the first direct evidence of the toxic effects of a tau fragment biologically produced in the context of these diseases in vertebrate neurons that develop in situ.

How does parkinsonism start? Prodromal parkinsonism motor changes in idiopathic REM sleep behaviour disorder

Parkinsonism, as a gradually progressive disorder, has a prodromal interval during which neurodegeneration has begun but cardinal manifestations have not fully developed. A systematic direct assessment of this interval has never been performed. Since patients with idiopathic REM sleep behaviour disorder are at very high risk of parkinsonism, they provide a unique opportunity to observe directly the development of parkinsonism. Patients with idiopathic REM sleep behaviour disorder in an ongoing cohort study were evaluated annually with several quantitative motor measures, including the Unified Parkinson's Disease Rating Scale, Purdue Pegboard, alternate-tap test and timed up-and-go. Patients who developed parkinsonism were identified from this cohort and matched according to age to normal controls. Their results on motor testing from the preceding years were plotted, and then assessed with regression analysis, to determine when markers first deviated from normal values. Sensitivity and specificity of quantitative motor markers for diagnosing prodromal parkinsonism were assessed. Of 78 patients, 20 developed parkinsonism. On regression analysis, the Unified Parkinson's Disease Rating Scale first intersected normal values at an estimated 4.5 years before diagnosis. Voice and face akinesia intersected earliest (estimated prodromal interval = 9.8 years), followed by rigidity (4.4 years), gait abnormalities (4.4 years) and limb bradykinesia (4.2 years). Quantitative motor tests intersected normal values at longer prodromal intervals than subjective examination (Purdue Pegboard = 8.6 years, alternate-tap = 8.2, timed up-and-go = 6.3). Using Purdue Pegboard and the alternate-tap test, parkinsonism could be detected with 71-82% sensitivity and specificity 3 years before diagnosis, whereas a Unified Parkinson's Disease Rating Scale score >4 identified prodromal parkinsonism with 88% sensitivity and 94% specificity 2 years before diagnosis. Removal of action tremor scores improved sensitivity to 94% and specificity to 97% at 2 years before diagnosis (cut-off >3). Although distinction between conditions was often difficult, prodromal dementia with Lewy bodies appeared to have a slower progression than Parkinson's disease (prodromal interval = 6.0 versus 3.8 years). Using a cut-off of Unified Parkinson's Disease Rating Scale >3 (excluding action tremor), 25% of patients with 'still-idiopathic' REM sleep behaviour disorder demonstrated evidence of possible prodromal parkinsonism. Therefore, using direct assessment of motor examination before parkinsonism in a REM sleep behaviour disorder, we have estimated a prodromal interval of ∼4.5 years on the Unified Parkinson's Disease Rating Scale; other quantitative markers may detect parkinsonism earlier. Simple quantitative motor measures may be capable of reliably detecting parkinsonism, even before a clinical diagnosis can be made by experienced movement disorders neurologists.

Pardoprunox as adjunct therapy to levodopa in patients with Parkinson's disease experiencing motor fluctuations: results of a double-blind, randomized, placebo-controlled, trial

AIMS

To determine the efficacy and safety of pardoprunox in levodopa-treated patients with Parkinson's disease (PD) experiencing motor fluctuations.

METHODS

Patients were randomized to pardoprunox (up to 42 mg/day, n = 150) or placebo (n = 144). Pardoprunox was titrated to an optimal dose over 7 weeks, followed by a 12-week stable dose period. The primary efficacy variable was the change from baseline to study endpoint in total daily OFF time, based on patient diaries. Secondary analyses included the change in ON time without troublesome dyskinesias, UPDRS-ADL + Motor ON, UPDRS-ADL OFF and PDQ-39. Subgroup analyses explored the impact of pardoprunox on dyskinesias (UPDRS items 32 + 33), depression (Hospital Anxiety Depression Scale) and pain (Visual Analogue Scale).

RESULTS

Pardoprunox significantly reduced OFF time versus placebo (-1.62 h/day versus -0.92 h/day, respectively, p = 0.0215). Compared to placebo, pardoprunox improved ON time without troublesome dyskinesias (p = 0.0386), UPDRS-ADL + Motor ON (p = 0.0003), and UPDRS-ADL OFF (p < 0.0001), while no significant difference was observed on PDQ-39. A high drop-out rate due to adverse events (AEs) (pardoprunox, 37%; placebo, 12%) suggested that the selected dose range may have been too high, and/or titration was too rapid.

CONCLUSIONS

Pardoprunox decreased OFF time and increased ON time without troublesome dyskinesias in levodopa-treated PD patients. The high drop-out rate at the selected doses justifies the investigation of lower doses. The impact of pardoprunox on dyskinesias and non-motor symptoms deserves further investigation.

Phenotype in parkinsonian and nonparkinsonian LRRK2 G2019S mutation carriers

OBJECTIVES

Using a family study design, we describe the motor and nonmotor phenotype in probands with LRRK2 G2019S mutations and family members and compare these individuals to patients with idiopathic Parkinson disease (iPD) and unrelated controls.

METHODS

Probands with G2019S mutations and their first-degree relatives, subjects with iPD, and unrelated control subjects were identified from 4 movement disorders centers. All underwent neurologic examinations and tests of olfaction, color vision, anxiety, and depression inventories.

RESULTS

Tremor was more often a presenting feature among 25 individuals with LRRK2-associated PD than among 84 individuals with iPD. Subjects with LRRK2-PD had better olfactory identification compared with subjects with iPD, higher Beck Depression Inventory scores, and higher error scores on Farnsworth-Munsell 100-Hue test of color discrimination. Postural or action tremor was more common among 29 nonmanifesting mutation carriers compared with 53 noncarriers within the families. Nonparkinsonian family members had higher Unified Parkinson's Disease Rating Scale motor scores, more constipation, and worse color discrimination than controls, regardless of mutation status.

CONCLUSIONS

Although tremor is a more common presenting feature of LRRK2-PD than iPD and some nonmotor features differed in degree, the phenotype is largely overlapping. Postural or action tremor may represent an early sign. Longitudinal evaluation of a large sample of nonmanifesting carriers will be required to describe any premotor phenotype that may allow early diagnosis.

Clinical vignettes in Parkinson's disease: a collection of unusual medication-induced hallucinations, delusions, and compulsive behaviours

Hallucinations, delusions, and compulsive behaviors are frequent iatrogenic complications of the treatment of motor dysfunction in Parkinson's disease (PD). Although these have been studied, and the phenomenology described, there are few detailed descriptions of the various psychiatric problems our treated PD patients live with that allow physicians who do not have a great deal of experience with PD patients to appreciate the extent of their altered lives. This report is a compilation of vignettes describing these behavioral problems that the treating neurologist or psychiatrist attributed to the medications used for treating PD.

Drug-induced deactivation of inhibitory networks predicts pathological gambling in PD

OBJECTIVE

Some patients with Parkinson disease (PD) develop pathological gambling when treated with dopamine agonists (DAs). However, little is known about DA-induced changes in neuronal networks that may underpin this drug-induced change in behavior in vulnerable individuals. In this case-control study, we aimed to investigate DA-induced changes in brain activity that may differentiate patients with PD with DA-induced pathological gambling (gamblers) from patients with PD without such a history (controls).

METHODS

Following overnight withdrawal of antiparkinsonian medication, patients were studied with H₂(15)O PET before and after administration of DA (3 mg apomorphine) to measure changes in regional cerebral blood flow as an index of regional brain activity during a card selection game with probabilistic feedback.

RESULTS

We observed that the direction of DA-related activity change in brain areas that are implicated in impulse control and response inhibition (lateral orbitofrontal cortex, rostral cingulate zone, amygdala, external pallidum) distinguished gamblers from controls. DA significantly increased activity in these areas in controls, while gamblers showed a significant DA-induced reduction of activity.

CONCLUSIONS

We propose that in vulnerable patients with PD, DAs produce an abnormal neuronal pattern that resembles those found in nonparkinsonian pathological gambling and drug addiction. DA-induced disruption of inhibitory key functions--outcome monitoring (rostral cingulate zone), acquisition and retention of negative action-outcome associations (amygdala and lateral orbitofrontal cortex)--together with restricted access of those areas to executive control (external pallidum)--may well explain loss of impulse control and response inhibition in vulnerable patients with PD, thereby fostering the development of pathological gambling.

Patient perception of dyskinesia in Parkinson's disease

OBJECTIVE

To evaluate the perception of patients with Parkinson's disease (PD) regarding dyskinesia.

DESIGN

Multicentre survey.

SETTING

Tertiary referral centres.

PATIENTS

Patients with PD participated in a survey: those not on dopaminergic medications (group I), those on dopaminergic medications without dyskinesia (group II) and those on dopaminergic medications with dyskinesia (group III).

INTERVENTION

After a short standardised description and explanation of dyskinesia was provided, patients were asked about the nature and source of prior knowledge of dyskinesia. They were then asked about their perceptions of dyskinesia. Patients in group III were also asked about the duration, the severity of dyskinesia and whether their perception of this problem had changed since its appearance.

MAIN OUTCOME MEASURES

Level of concern regarding dyskinesia and whether their perception of dyskinesia would have changed their preference of treatment. Results 259 PD patients completed the survey (group I, 52; group II, 102; group III, 105). Patients with dyskinesia were significantly less concerned about dyskinesia than patients without dyskinesia and were more likely to choose dyskinesia over being parkinsonian. Patients who required fewer changes in medications because of dyskinesia were more likely to choose dyskinesia over parkinsonism.

CONCLUSION

Patients with PD experiencing dyskinesia are less likely to be concerned about dyskinesia and more likely to prefer dyskinesia over parkinsonian symptoms than patients without dyskinesia.

Multicenter analysis of glucocerebrosidase mutations in Parkinson's disease

BACKGROUND

Recent studies indicate an increased frequency of mutations in the gene encoding glucocerebrosidase (GBA), a deficiency of which causes Gaucher's disease, among patients with Parkinson's disease. We aimed to ascertain the frequency of GBA mutations in an ethnically diverse group of patients with Parkinson's disease.

METHODS

Sixteen centers participated in our international, collaborative study: five from the Americas, six from Europe, two from Israel, and three from Asia. Each center genotyped a standard DNA panel to permit comparison of the genotyping results across centers. Genotypes and phenotypic data from a total of 5691 patients with Parkinson's disease (780 Ashkenazi Jews) and 4898 controls (387 Ashkenazi Jews) were analyzed, with multivariate logistic-regression models and the Mantel-Haenszel procedure used to estimate odds ratios across centers.

RESULTS

All 16 centers could detect two GBA mutations, L444P and N370S. Among Ashkenazi Jewish subjects, either mutation was found in 15% of patients and 3% of controls, and among non-Ashkenazi Jewish subjects, either mutation was found in 3% of patients and less than 1% of controls. GBA was fully sequenced for 1883 non-Ashkenazi Jewish patients, and mutations were identified in 7%, showing that limited mutation screening can miss half the mutant alleles. The odds ratio for any GBA mutation in patients versus controls was 5.43 across centers. As compared with patients who did not carry a GBA mutation, those with a GBA mutation presented earlier with the disease, were more likely to have affected relatives, and were more likely to have atypical clinical manifestations.

CONCLUSIONS

Data collected from 16 centers demonstrate that there is a strong association between GBA mutations and Parkinson's disease.

Tauopathies with parkinsonism: clinical spectrum, neuropathologic basis, biological markers, and treatment options

Tauopathies with parkinsonism represent a spectrum of disease entities unified by the pathologic accumulation of hyperphosphorylated tau protein fragments within the central nervous system. These pathologic characteristics suggest shared pathogenetic pathways and possible molecular targets for disease-modifying therapeutic interventions. Natural history studies, for instance, in progressive supranuclear palsy, frontotemporal dementia with parkinsonism linked to chromosome 17, corticobasal degeneration, and Niemann-Pick disease type C as well as in amyotrophic lateral sclerosis/Parkinson-dementia complex permit clinical characterization of the disease phenotypes and are crucial to the development and validation of biological markers for differential diagnostics and disease monitoring, for example, by use of neuroimaging or proteomic approaches. The wide pathologic and clinical spectrum of the tauopathies with parkinsonism is reviewed in this article, and perspectives on future advances in the understanding of the pathogenesis are given, together with potential therapeutic strategies.

Safety and tolerability of pardoprunox, a new partial dopamine agonist, in a randomized, controlled study of patients with advanced Parkinson's disease

AIMS

To investigate the safety and tolerability of pardoprunox (SLV308), a novel partial dopamine agonist, as an adjunct to levodopa in patients with advanced Parkinson's disease, using two titration schedules.

METHODS

Patients were randomized to pardoprunox (n = 51) or placebo (n = 11). Pardoprunox was titrated to the highest tolerated dose (range, 0.3-42 mg/day) over 7 weeks, using a gradual dose escalation without intermediate steps (group 1) or with intermediate steps (group 2).

RESULTS

The cumulative drop-out rate was greater in group 1 (without intermediate steps, 56.0%) than in group 2 (with intermediate steps, 34.6%), or with placebo (9.1%). In group 2, doses up to 18 mg/day were well tolerated with a cumulative drop-out rate of 7.7% (2/26) and a drop-out rate due to adverse events of 4.0% (1/26). The most common adverse events reported were nausea, vomiting, headache, and dizziness. There was a trend for reduced OFF time (p = 0.054) in the combined pardoprunox group compared to placebo.

CONCLUSIONS

The pardoprunox safety and tolerability profile as an adjunct to levodopa was improved using a gradual titration schedule that included intermediate dose steps. Using this titration, doses up to 18 mg/day were well tolerated.

Increased striatal dopamine release in Parkinsonian patients with pathological gambling: a [11C] raclopride PET study

Pathological gambling is an impulse control disorder reported in association with dopamine agonists used to treat Parkinson's disease. Although impulse control disorders are conceptualized as lying within the spectrum of addictions, little neurobiological evidence exists to support this belief. Functional imaging studies have consistently demonstrated abnormalities of dopaminergic function in patients with drug addictions, but to date no study has specifically evaluated dopaminergic function in Parkinson's disease patients with impulse control disorders. We describe results of a [(11)C] raclopride positron emission tomography (PET) study comparing dopaminergic function during gambling in Parkinson's disease patients, with and without pathological gambling, following dopamine agonists. Patients with pathological gambling demonstrated greater decreases in binding potential in the ventral striatum during gambling (13.9%) than control patients (8.1%), likely reflecting greater dopaminergic release. Ventral striatal bindings at baseline during control task were also lower in patients with pathological gambling. Although prior imaging studies suggest that abnormality in dopaminergic binding and dopamine release may be markers of vulnerability to addiction, this study presents the first evidence of these phenomena in pathological gambling. The emergence of pathological gambling in a number of Parkinson's disease patients may provide a model into the pathophysiology of this disorder.

Tauopathies with parkinsonism: clinical spectrum, neuropathologic basis, biological markers, and treatment options

Tauopathies with parkinsonism represent a spectrum of disease entities unified by the pathologic accumulation of hyperphosphorylated tau protein fragments within the central nervous system. These pathologic characteristics suggest shared pathogenetic pathways and possible molecular targets for disease-modifying therapeutic interventions. Natural history studies, for instance, in progressive supranuclear palsy, frontotemporal dementia with parkinsonism linked to chromosome 17, corticobasal degeneration, and Niemann-Pick disease type C as well as in amyotrophic lateral sclerosis/Parkinson-dementia complex permit clinical characterization of the disease phenotypes and are crucial to the development and validation of biological markers for differential diagnostics and disease monitoring, for example, by use of neuroimaging or proteomic approaches. The wide pathologic and clinical spectrum of the tauopathies with parkinsonism is reviewed in this article, and perspectives on future advances in the understanding of the pathogenesis are given, together with potential therapeutic strategies.

Bilateral subthalamic stimulation in Parkin and PINK1 parkinsonism

OBJECTIVES

To study the frequency of different gene mutations in patients with early-onset parkinsonism and bilateral subthalamic nucleus deep brain stimulation (STN-DBS) and the short- and long-term surgical outcome in mutation-positive (MUT+) and -negative (MUT-) patients.

METHODS

Eighty patients with disease onset at age <or= 45 years and bilateral STN-DBS were screened for mutations in the Parkin gene and PINK1 gene and for the recurrent p.G2019S mutation in the LRRK2 gene. The Unified Parkinson's Disease Rating Scale (UPDRS) and Hoehn and Yahr (H-Y) scale were used to compare the on- and off-medication conditions preoperatively and in the off-medication/on-stimulation condition postoperatively.

RESULTS

We identified 12 mutation carriers (11 Parkin [6 with 2 mutated alleles, 5 with 1 mutated allele], 1 homozygous PINK1). There were no clinical differences between the MUT- and MUT+ patients preoperatively, except for more severe H-Y stage and postural and gait scores in the on-medication state in the MUT+ group. During the first year after surgery, MUT- patients showed better clinical improvement (56% motor UPDRS improvement) compared with MUT+ patients (36%). However, in the long-term follow-up (3-6 years), both groups presented with the same degree of clinical improvement (MUT-: 44% vs MUT+: 42%). Although the MUT+ group showed more severe axial signs preoperatively, MUT- patients developed levodopa- and deep brain stimulation-resistant axial signs within the first 3 to 6 years postoperatively, which diminished the initial benefit soon after surgery.

CONCLUSIONS

Patients with Parkin or PINK1 mutations benefit from subthalamic nucleus deep brain stimulation. However, the clinical response is not superior to non-mutation carriers and might be limited by more advanced axial motor symptoms at a relatively early disease stage.

Myoclonus-dystonia: significance of large SGCE deletions

Myoclonus-dystonia (M-D) is an autosomal-dominant movement disorder caused by mutations in SGCE. We investigated the frequency and type of SGCE mutations with emphasis on gene dosage alterations and explored the associated phenotypes. We tested 35 M-D index patients by multiplex ligation-dependent probe amplification (MLPA) and genomic sequencing. Mutations were found in 26% (9/35) of the cases, all but three with definite M-D. Two heterozygous deletions of the entire SGCE gene and flanking DNA and a heterozygous deletion of exon 2 only were detected, accounting for 33% (3/9) of the mutations found. Both large deletions contained COL1A2 and were additionally associated with joint problems. Further, we discovered one novel small deletion (c.771_772delAT, p.C258X) and four recurrent point mutations (c.289C>T, p.R97X; c.304C>T, p.R102X; c.709C>T, p.R237X; c.1114C>T, p.R372X). A Medline search identified 22 articles on SGCE mutational screening. Sixty-four unrelated M-D patients were described with 41 different mutations. No genotype-phenotype association was found, except in patients with deletions encompassing additional genes. In conclusion, a rigorous clinical preselection of patients and careful accounting for non-motor signs should precede mutational tests. Gene dosage studies should be included in routine SGCE genetic testing.

Isolated diaphragmatic tremor: Is there a spectrum in "respiratory myoclonus"?

BACKGROUND

Respiratory myoclonus or diaphragmatic flutter is an unusual movement disorder with abnormal diaphragmatic activity, which may be associated with respiratory symptoms. The effects of distracting maneuvers on diaphragmatic activity have not been investigated.

METHODS

Two patients with nondisabling abdominal movements of suspected diaphragmatic origin were studied with surface and needle electromyography (EMG).

RESULTS

The abdominal movements resulted from isolated, rhythmic diaphragmatic contractions with variable EMG burst duration, suppressibility with breath-holding and distracting maneuvers, and other attributes of volitional control.

CONCLUSION

"Respiratory myoclonus" may be a heterogeneous disorder ranging from synchronous movements of the diaphragm and other respiratory muscles associated with respiratory compromise, to diaphragmatic movements under at least some volitional control with no respiratory or functional disability. The latter group could be designated phenomenologically as "isolated diaphragmatic tremor."

Genotype-phenotype correlation of paroxysmal nonkinesigenic dyskinesia

BACKGROUND

Paroxysmal nonkinesigenic dyskinesia (PNKD) is a rare disorder characterized by episodic hyperkinetic movement attacks. We have recently identified mutations in the MR-1 gene causing familial PNKD.

METHODS

We reviewed the clinical features of 14 kindreds with familial dyskinesia that was not clearly induced by movement or during sleep. Of these 14 kindreds, 8 had MR-1 mutations and 6 did not.

RESULTS

Patients with PNKD with MR-1 mutations had their attack onset in youth (infancy and early childhood). Typical attacks consisted of a mixture of chorea and dystonia in the limbs, face, and trunk, and typical attack duration lasted from 10 minutes to 1 hour. Caffeine, alcohol, and emotional stress were prominent precipitants. Attacks had a favorable response to benzodiazepines, such as clonazepam and diazepam. Attacks in families without MR-1 mutations were more variable in their age at onset, precipitants, clinical features, and response to medications. Several were induced by persistent exercise.

CONCLUSIONS

Paroxysmal nonkinesigenic dyskinesia (PNKD) should be strictly defined based on age at onset and ability to precipitate attacks with caffeine and alcohol. Patients with this clinical presentation (which is similar to the phenotype initially reported by Mount and Reback) are likely to harbor myofibrillogenesis regulator 1 (MR-1) gene mutations. Other "PNKD-like" families exist, but atypical features suggests that these subjects are clinically distinct from PNKD and do not have MR-1 mutations. Some may represent paroxysmal exertional dyskinesia.

Long-term outcome of bilateral pallidal deep brain stimulation for primary cervical dystonia

Ten patients with severe cervical dystonia (CD) unresponsive to medical treatment underwent bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) and were followed for 31.9 +/- 20.9 months. At last follow-up, the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) severity score improved by 54.8%, the TWSTRS disability score improved by 59.1%, and the TWSTRS pain score improved by 50.4%. Bilateral GPi DBS is an effective long-term therapy in patients with CD.

Subthalamic nucleus stimulation modulates afferent inhibition in Parkinson disease

BACKGROUND

Peripheral sensory stimulation at the wrist inhibits the motor cortex as measured by transcranial magnetic stimulation at interstimulus intervals of approximately 20 ms (short latency afferent inhibition [SAI]) and 200 ms (long latency afferent inhibition [LAI]). Previous studies suggested that reduced SAI in Parkinson disease (PD) reflects adverse effect of dopaminergic medications and reduced LAI may be related to nondopaminergic manifestations of PD. We hypothesize that subthalamic nucleus (STN) deep brain stimulation (DBS) may correct these deficiencies.

METHODS

We studied the effects of STN DBS on SAI and LAI in seven PD patients and age-matched controls. PD patients were studied in an off medication followed by an on medication session, with the stimulator switched on or off in random order in each session.

RESULTS

In the on medication session, SAI was reduced in the stimulator off condition and was restored by STN DBS. LAI was partially normalized by STN DBS in the medication on condition.

CONCLUSIONS

Subthalamic nucleus (STN) stimulation improves short latency afferent inhibition, suggesting that it could normalize pathways that are adversely affected by dopaminergic medications. The effect of STN stimulation on long latency afferent inhibition suggests that it may influence nondopaminergic pathways involved in sensorimotor integration.

Prevalence of repetitive and reward-seeking behaviors in Parkinson disease

We surveyed 297 patients with Parkinson disease (PD) with systematic screens and rigorous definitional criteria. Pathologic hypersexuality lifetime prevalence was 2.4%. Compulsive shopping was 0.7%. Combined with our pathologic gambling data, the lifetime prevalence of these behaviors was 6.1% and increases to 13.7% in patients on dopamine agonists.

Vitamins and entacapone in levodopa-induced hyperhomocysteinemia: A randomized controlled study

Elevated homocysteine is associated with increased risk of heart disease, stroke, and dementia. Therapy of Parkinson disease (PD) with levodopa elevates homocysteine. The authors conducted a 6-week, multicenter, randomized, double-blind, placebo-controlled trial to test whether folate 1 mg/vitamin B(12) 500 microg or entacapone reduced serum homocysteine in 35 levodopa-treated PD patients. Levodopa initiation caused a small elevation in homocysteine. Vitamin therapy, but not entacapone, resulted in a decrease in homocysteine compared to placebo.

Prospective prevalence of pathologic gambling and medication association in Parkinson disease

The authors prospectively screened 297 patients with Parkinson disease (PD), who attended a tertiary clinic, using a modified South Oaks Gambling Scale. Lifetime prevalence of pathologic gambling (PG) was 3.4% and on any dopamine agonist was 7.2%. PG was associated with earlier PD onset and with dopamine agonists but not with agonist subtype or doses. We found no association with a potent D3 receptor agonist.

Corticobasal ganglionic degeneration and progressive supranuclear palsy presenting with cognitive decline

Corticobasal ganglionic degeneration (CBGD) and progressive supranuclear palsy (PSP) were originally described in the sixties as predominantly motor syndromes. Over the years, the detailed study of additional cases of CBGD has shown that it is a distinctive histological entity which can often present as dementia or aphasia. Although some pathological features of CBGD overlap with those of other forms of non-Alzheimer non-Lewy body dementia, the distribution and relative number of these abnormalities and the distinctive pattern of tau immunodeposits allows the distinction of CBGD from Pick's disease and fronto-temporal dementia. In contrast, PSP only rarely presents with prominent dementia or behavioral changes. In these unusual PSP cases, care must be taken to exclude the diagnoses of CBGD and familial tangle-only dementia.

The 'essentials' of essential palatal tremor: a reappraisal of the nosology

Essential palatal tremor (EPT) is an uncommon disorder, distinct from symptomatic palatal tremor (SPT), but characterized by superficially similar rhythmic movements of the soft palate. While the pathophysiology of SPT has been relatively well defined, this is not the case in EPT. Based on an analysis of 103 published cases, we reviewed EPT in the context of other movement disorders with similar features and outline possible pathophysiological mechanisms. Phenomenologically it remains best classified as a tremor. Four major causes, including a central generator, peripheral/mechanical, voluntary/special skill and psychogenic, appear to account for the majority of cases of EPT, although there is considerable overlap in the pathogenic mechanisms underlying these categories. Among the cases reviewed, a large proportion fit into the latter two categories, although there are others where multiple mechanisms are likely at play. Based on our reappraisal, we suggest a change in designation to 'isolated palatal tremor', with primary and secondary subtypes. This retains the distinction from SPT and emphasizes the non-uniform, heterogeneous nature of the disorder.

LRRK2 gene in Parkinson disease: mutation analysis and case control association study

BACKGROUND

In addition to the four well-confirmed genes linked to early-onset Parkinson disease (PD) (SNCA, PARKIN, DJ-1, and PINK1), mutations in the leucine-rich repeat kinase 2 gene (LRRK2) have recently been identified in families with autosomal dominant late-onset PD.

OBJECTIVE

To perform mutation analysis of LRRK2 in probands of families showing dominant inheritance of PD and to conduct a case control association study to test the hypothesis that common coding variations might be associated with increased susceptibility to PD.

METHODS

All 51 LRRK2 coding exons were sequenced in 23 probands and the mutation frequencies were evaluated in 180 neurologically normal control subjects. For the association study the authors genotyped four coding LRRK2 polymorphisms in 250 normal control subjects and 121 patients with PD (predominantly white patients of Canadian origin), 84% of whom had age at onset before 50 years and 42% had a positive family history.

RESULTS

The authors identified three probands with heterozygous LRRK2 mutations: two of them have the known G2019S substitution and one proband has a novel I1371V substitution. Mutation analysis of a large family demonstrated complete segregation of the G2019S with PD. However, there was no association between PD and any of the four polymorphisms at the allelic or genotypic levels (p > 0.17). Furthermore, the authors did not detect a modifying effect for any genotype or of APOE genotypes upon the age at onset in the PD group (p > 0.20).

CONCLUSIONS

The results support the prior suggestion that LRRK2 mutations cause PD. The disease in the families reported here presents a phenotype indistinguishable from typical PD. All three families demonstrate a very variable age at onset that is not explained by APOE genotypes. The common coding variations in the LRRK2 gene neither constitute strong PD risk factors nor modify the age at onset; however, the possibility of a modest risk effect remains to be assessed in large datasets.

Mirror movements in parkinsonism: evaluation of a new clinical sign

BACKGROUND

Mirror movements (MM) are not widely appreciated in parkinsonism and no report has evaluated this clinical sign in detail.

OBJECTIVES

To define the parkinsonian clinical features associated with MM in patients with early, asymmetric parkinsonism.

METHODS

Twenty seven patients with early Parkinson's disease were evaluated using a standardised videotaping protocol. MM were scored from blinded video assessment using a clinical scale that rates the amplitude, distribution, and proportion of mirroring in the less affected limb. Parkinsonian features were combined into axial and lateralised scores using related items of the Unified Parkinson's Disease Rating Scale.

RESULTS

MM were present in 24 of 27 patients. There was a significant linear correlation between the degree of asymmetry of motor deficits and MM on the less affected side. The effect of asymmetry was greater when the proportional rather than the absolute motor difference between sides was largest. Asymmetry in leg rigidity was the most important examination feature in the prediction of contralateral foot mirroring.

CONCLUSIONS

MM are a clinical feature of the unaffected or less affected side in mild asymmetric parkinsonism. Their presence may be a useful clinical finding in early parkinsonism.

Bilateral deep brain stimulation in Parkinson's disease: a multicentre study with 4 years follow-up

Deep brain stimulation (DBS) is associated with significant improvement of motor complications in patients with severe Parkinson's disease after some 6-12 months of treatment. Long-term results in a large number of patients have been reported only from a single study centre. We report 69 Parkinson's disease patients treated with bilateral DBS of the subthalamic nucleus (STN, n = 49) or globus pallidus internus (GPi, n = 20) included in a multicentre study. Patients were assessed preoperatively and at 1 year and 3-4 years after surgery. The primary outcome measure was the change in the 'off' medication score of the Unified Parkinson's Disease Rating Scale motor part (UPDRS-III) at 3-4 years. Stimulation of the STN or GPi induced a significant improvement (50 and 39%; P < 0.0001) of the 'off' medication UPDRS-III score at 3-4 years with respect to baseline. Stimulation improved cardinal features and activities of daily living (ADL) (P < 0.0001 and P < 0.02 for STN and GPi, respectively) and prolonged the 'on' time spent with good mobility without dyskinesias (P < 0.00001). Daily dosage of levodopa was significantly reduced (35%) in the STN-treated group only (P < 0.001). Comparison of the improvement induced by stimulation at 1 year with 3-4 years showed a significant worsening in the 'on' medication motor states of the UPDRS-III, ADL and gait in both STN and GPi groups, and speech and postural stability in the STN-treated group. Adverse events (AEs) included cognitive decline, speech difficulty, instability, gait disorders and depression. These were more common in patients treated with DBS of the STN. No patient abandoned treatment as a result of these side effects. This experience, which represents the first multicentre study assessing the long-term efficacy of either STN or GPi stimulation, shows a significant and substantial clinically important therapeutic benefit for at least 3-4 years in a large cohort of patients with severe Parkinson's disease.

Changes in cortical excitability with thalamic deep brain stimulation

BACKGROUND

Deep brain stimulation (DBS) is an effective treatment for several movement disorders. However, its mechanism of action is largely unknown. Both lesioning and DBS of the ventralis intermedius (VIM) nucleus of thalamus improve essential tremor. Although DBS was initially thought to inhibit the target neurons, recent studies suggest that DBS activates neurons.

OBJECTIVE

To test the hypothesis that thalamic DBS activates the target area in patients with essential tremor.

METHODS

Cortical excitability was assessed in seven unmedicated patients with essential tremor using unilateral stimulators implanted in the VIM of the dominant hemisphere and in 11 healthy controls using transcranial magnetic stimulation (TMS). Patients were studied during optimal DBS (ON condition), half the optimal frequency (HALF), and with DBS off (OFF) in random order. Tremor was assessed after a change in DBS setting. Electromyography was recorded from the dominant hand, and TMS was applied over the contralateral motor cortex using single and paired pulses to elicit motor evoked potentials (MEPs). MEP recruitment was determined using stimulus intensities from 100% to 150% of motor threshold.

RESULTS

Tremor scores were significantly improved with DBS ON. Analysis of variance showed a significant interaction between condition (ON, HALF, OFF, Normal) and stimulus intensity on MEP amplitude. During DBS ON MEP amplitudes were significantly higher compared with controls at high but not at low TMS intensities.

CONCLUSION

Because the ventralis intermedius (VIM) projects directly to the motor cortex, the high motor evoked potential amplitude with deep brain stimulation ON suggests that VIM DBS activates rather than inhibits the target area.

A writing device improves writing in primary writing tremor

Primary writing tremor (PWT) is task-specific and interferes with handwriting. Several reports have shown a beneficial response of this disorder to stereotactic functional neurosurgery. Significant improvement with a writing device was demonstrated with blind rating of handwriting and spiral drawing samples collected before and during its use in nine patients with PWT, suggesting that this therapeutic modality should be tried before considering chronic pharmacotherapy or functional neurosurgery.

Survival in Parkinson disease: Thirteen-year follow-up of the DATATOP cohort

OBJECTIVE

To investigate predictors of survival in Parkinson disease (PD).

METHODS

Vital status was determined in 800 subjects enrolled in a clinical trial of deprenyl (selegiline) and tocopherol 13 years earlier.

RESULTS

Two hundred ninety-six deaths were recorded. There was no difference in the standardized mortality ratios across gender or age group. In univariate analyses, PD-specific variables associated with mortality were increased symmetry of parkinsonism, gait dysfunction as an initial symptom, severity of parkinsonism, and rate of worsening of parkinsonism prior to study enrollment. Cumulative exposure to deprenyl was not associated with mortality. In multivariable analysis, severity of parkinsonism and rate of worsening of parkinsonism remained associated with mortality. A poorer response to levodopa was associated with increased mortality independent of disease severity or dosage of levodopa. Results were unchanged when the analysis was restricted to 747 subjects maintaining a most likely diagnosis of PD throughout 6 years of active follow-up.

CONCLUSIONS

Parkinson disease did not affect survival differently across gender or age groups in this selected group of otherwise healthy clinical trial participants. Severity and rate of worsening of parkinsonism and response to levodopa are strongly related to survival.

Emergence of restless legs syndrome during subthalamic stimulation for Parkinson disease

The authors systematically studied the emergence of restless legs syndrome (RLS) after subthalamic nucleus (STN) deep brain stimulation (DBS) for Parkinson disease (PD). Postoperatively, 11 of 195 patients with STN DBS reported new problematic symptoms of RLS. The mean reduction in antiparkinsonian medication was 74%. The mean RLS score at diagnosis was 15 (+/-5.9) of a possible 24 points and after symptomatic drug therapy 4.3 (+/-3.1) points. Reduction of antiparkinsonian medication during STN DBS may unmask symptoms of RLS and complicate therapy of both RLS and PD.

Thalamic deep brain stimulation activates the cerebellothalamocortical pathway

To investigate the mechanism of action of deep brain stimulation (DBS), the authors studied the effects of thalamic DBS on the cerebellothalamocortical (CTC) pathway. With DBS turned off, excitability of the CTC pathway was reduced. Turning DBS on resulted in facilitation of the CTC pathway. Therefore, thalamic DBS appears to activate rather than inhibit the target area.

Evaluation of the pull test technique in assessing postural instability in Parkinson's disease

Variability in pull test (PT) performance can lead to inadequate evaluation of postural instability in patients with Parkinson's disease (PD). Assessing 66 PTs by 25 examiners, at least two of four raters agreed that specific items were performed incorrectly for stance in 27.3%, for strength and briskness of the pull in 84.9%, for examiner's response in 36.4%, and for technique issues in 9.1%. Examiners were consistent in their errors, and only 9% of examinations were error-free.

DJ-1 (PARK7) mutations are less frequent than Parkin (PARK2) mutations in early-onset Parkinson disease

BACKGROUND

Mutations in the Parkin gene (PARK2) are the most commonly identified cause of recessively inherited early-onset Parkinson disease (EOPD) but account for only a portion of cases. DJ-1 (PARK7) was recently reported as a second gene associated with recessively inherited PD with a homozygous exon deletion and a homozygous point mutation in two families.

METHODS

To investigate the frequency of DJ-1 mutations, the authors performed mutational analysis of all six coding exons of DJ-1 in 100 EOPD patients. For the detection of exon rearrangements, the authors developed a quantitative duplex PCR assay. Denaturing high performance liquid chromatography analysis was used to screen for point mutations and small deletions. Further, Parkin analysis was performed as previously described.

RESULTS

The authors identified two carriers of single heterozygous loss-of-function DJ-1 mutations, including a heterozygous deletion of exons 5 to 7 and an 11-base pair deletion, removing the invariant donor splice site in intron 5. Interestingly, both DJ-1 mutations identified in this study were found in the heterozygous state only. The authors also detected a polymorphism (R98Q) in 1.5% of the chromosomes in both the patient and control group. In the same patient sample, 17 cases were detected with mutations in the Parkin gene.

CONCLUSIONS

Mutations in DJ-1 are less frequent than mutations in Parkin in EOPD patients but should be considered as a possible cause of EOPD. The effect of single heterozygous mutations in DJ-1 on the nigrostriatal system, as described for heterozygous changes in Parkin and PARK6, remains to be elucidated.

Involvement of the human subthalamic nucleus in movement preparation

BACKGROUND

Although it has long been recognized that the basal ganglia play a major role in motor control, their precise functions remain unclear. As patients with Parkinson's disease (PD) have difficulties initiating movement, the basal ganglia may be involved in movement preparation. The subthalamic nucleus (STN) is particularly suited to play a role in movement preparation because it receives direct input from the supplementary motor area through the corticosubthalamic pathway.

METHODS

Taking advantage of the electrodes surgically implanted in the STN for deep brain stimulation (DBS) treatment in 13 PD patients, we recorded from the DBS electrodes and the scalp simultaneously while the patients were performing self-paced wrist extension movements.

RESULTS

Scalp recordings showed a slow, negative movement-related potential (MRP) in all patients studied (onset 1,690 +/- 336 milliseconds before electromyography onset). STN recordings showed premovement MRP in 11 of 13 patients. The STN activity occurred with both ipsilateral and contralateral hand movement. The onset time for STN MRP (contralateral 2,095 +/- 1,005 milliseconds, ipsilateral 2,020 +/- 920 milliseconds) was not significantly different from that for cortical MRP.

CONCLUSION

The STN or nearby structures are active before self-paced movement in humans.

Psychogenic dystonia

Psychogenic dystonia has been a controversial diagnosis over the past century. While this entity does exist, it makes up the minority of cases of dystonia seen at specialized centres. The diagnosis of psychogenic dystonia must only be undertaken by a neurologist with considerable experience in the assessment and treatment of organic dystonia. Features in the history and physical examination will reveal both clinical inconsistencies and incongruities with organic dystonia that support a psychogenic cause for the patient's symptoms. Patients with psychogenic dystonia suffer from motor conversion disorder, and co-morbid depression, anxiety and disorders of personality are frequent. While there have been no neuroimaging studies to date in patients with psychogenic dystonia, imaging studies in patients with organic dystonia offer insights on how one might assess this problem using functional neuroimaging. Neurophysiologic studies in patients with organic forms of dystonia may also be employed to further distinguish psychogenic from organic dystonia when doubt exists. The prognosis of psychogenic dystonia is disappointing, with the majority of patients suffering significant long-term disability. Recommendations are given regarding disclosure of the diagnosis of psychogenic dystonia to the patient as well as appropriate treatment.

Mutations in the epsilon-sarcoglycan gene found to be uncommon in seven myoclonus-dystonia families

Myoclonus-dystonia syndrome (MDS) is a disorder for which the major cause appears to be mutations in the epsilon-sarcoglycan gene (SGCE). The authors have now performed mutation screening in 22 affected individuals from seven families with findings of typical MDS. A novel 5-bp deletion in exon 7 of the gene in one family and the previously reported R102X nonsense mutation in exon 3 in two other families were identified. Mutations in the SGCE gene were found in the minority of families screened in this series.