Proficiency in positive vs. negative emotion identification and subjective well-being among long-term married elderly couples

Evidence is accruing that positive emotions play a crucial role in shaping a healthy interpersonal climate. Inspired by this research, the current investigation sought to shed light on the link between proficiency in identifying positive vs. negative emotions and a close partner's well-being. To this end, we conducted two studies with neurologically intact elderly married couples (Study 1) and an age-matched clinical sample, comprising married couples in which one spouse had been diagnosed with Parkinson's Disease (Study 2), which tends to hinder emotional expressivity. To assess proficiency in identifying emotions from whole body postures, we had participants in both studies complete a pointlight walker task, featuring four actors (two male, two female) expressing one positive (i.e., happiness) and three negative (i.e., sadness, anger, fear) basic emotions. Participants also filled out measures of subjective well-being. Among Study 1's neurologically intact spouses, greater expertise in identifying positive (but not negative) emotions was linked to greater partner life satisfaction (but not hedonic balance). Spouses of PD patients exhibited increased proficiency in identifying positive emotions relative to controls, possibly reflective of compensatory mechanisms. Complementarily, relative to controls, spouses of PD patients exhibited reduced proficiency in identifying negative emotions and a tendency to underestimate their intensity. Importantly, all of these effects attenuated with longer years from PD onset. Finally, there was evidence that it was increased partner expertise in identifying negative (rather than positive) emotional states that predicted greater life satisfaction levels among the PD patients and their spouses. Our results thus suggest that positive vs. negative emotions may play distinct roles in close relationship dynamics as a function of neurological status and disability trajectory.

Beyond and below the cortex: the contribution of striatal dysfunction to cognition and behaviour in neurodegeneration

Investigations of cognitive and behavioural changes in neurodegeneration have been mostly focussed on how cortical changes can explain these symptoms. In the proposed review, we will argue that the striatum has been overlooked as a critical nexus in understanding the generation of such symptoms. Although the striatum is historically more associated with motor dysfunction, there is increasing evidence from functional neuroimaging studies in the healthy that striatal regions modulate behaviour and cognition. This should not be surprising, as the striatum has strong anatomical connections to many cortical regions including the frontal, temporal and insula lobes, as well as some subcortical regions (amygdala, hippocampus). To date, however, it is largely unclear to what extent striatal regions are affected in many neurodegenerative conditions-and if so, how striatal dysfunction can potentially influence cognition and behaviour. The proposed review will examine the existing evidence of striatal changes across selected neurodegenerative conditions (Parkinson's disease, progressive supranuclear palsy, Huntington's disease, motor neuron disease, frontotemporal dementia and Alzheimer's disease), and will document their link with the cognitive and behavioural impairments observed. Thus, by reviewing the varying degrees of cortical and striatal changes in these conditions, we can start outlining the contributions of the striatal nexus to cognitive and behavioural symptoms. In turn, this knowledge will inform future studies investigating corticostriatal networks and also diagnostic strategies, disease management and future therapeutics of neurodegenerative conditions.

[Continuous subcutaneous infusion of apomorphine in Parkinson's disease: retrospective analysis of a series of 81 patients]

BACKGROUND

Continuous subcutaneous infusion of apomorphine (CAI) has shown efficacy in the treatment of motor fluctuations but its place in the therapeutic arsenal remains poorly defined in terms of indication, acceptability and long-term tolerance. Indeed, few studies have been carried out with a follow-up greater than 12 months. The main objective was to assess the quality of life of Parkinson's disease (PD) patients treated with CAI. We also evaluate the effectiveness on the motor fluctuations, the long-term tolerance of this treatment with its causes of discontinuation and the treatment regimens used.

METHODS

We conducted a retrospective study of 81 PD patients treated with CAI between April 2003 and June 2012. Data were collected from medical records. A repeated measures analysis of variance by the linear mixed model was used (significance level: 5%).

RESULTS

In August 2012, 27/81 patients were still treated with CAI with a mean duration of 28 months, 46/81 discontinued CAI (9 precociously), and 8 were lost to view. We didn't show improvement in the quality of life nor efficacy of CAI on the UPDRS IV score (P=0.54) and dyskinesia score (P=0.95). The CGI score patient also reflects this result with a majority response suggesting no significant change with CAI. We observed relative good cognitive and psychiatric tolerance. Adverse events were frequent but often benign. The average (±SD) rate of apomorphine was 3.15±1.71 mg/h and the oral dopaminergic treatment was decreased by 37.8%.

DISCUSSION

The results are consistent with the literature except for the lack of efficiency on motor fluctuations which may be due to the use of too small doses of apomorphine. This seems to be a leading cause of discontinuation of CAI, especially when it is associated with side effects or important constraints. For better efficiency on motor fluctuations, we recommend the use of apomorphine at higher doses to obtain an optimal continuous dopaminergic stimulation.

Molecular basis for preventing α-synuclein aggregation by a molecular tweezer

Recent work on α-synuclein has shown that aggregation is controlled kinetically by the rate of reconfiguration of the unstructured chain, such that the faster the reconfiguration, the slower the aggregation. In this work we investigate this relationship by examining α-synuclein in the presence of a small molecular tweezer, CLR01, which binds selectively to Lys side chains. We find strong binding to multiple Lys within the chain as measured by fluorescence and mass-spectrometry and a linear increase in the reconfiguration rate with concentration of the inhibitor. Top-down mass-spectrometric analysis shows that the main binding of CLR01 to α-synuclein occurs at the N-terminal Lys-10/Lys-12. Photo-induced cross-linking of unmodified proteins (PICUP) analysis shows that under the conditions used for the fluorescence analysis, α-synuclein is predominantly monomeric. The results can be successfully modeled using a kinetic scheme in which two aggregation-prone monomers can form an encounter complex that leads to further oligomerization but can also dissociate back to monomers if the reconfiguration rate is sufficiently high. Taken together, the data provide important insights into the preferred binding site of CLR01 on α-synuclein and the mechanism by which the molecular tweezer prevents self-assembly into neurotoxic aggregates by α-synuclein and presumably other amyloidogenic proteins.

Depressive symptoms in Parkinson's disease are related to reduced [123I]FP-CIT binding in the caudate nucleus

BACKGROUND

Depression is a common neuropsychiatric symptom in Parkinson's disease (PD). In previous research, PD-related depression was associated with striatal dopaminergic deficits, presumably due to degeneration of brainstem dopaminergic projections. Segregated areas of the striatum are crucially involved in various parallelly arranged cortical-striatal-thalamocortical circuits and serve functions in, among others, motor control or emotion. This suggests regional specificity of dopaminergic deficits in the striatum in motor and depressive symptoms in PD.

METHODS

In this cross-sectional retrospective study, we correlated severity scores of depressive and motor symptoms in 100 non-demented PD patients (median Hoehn & Yahr stage: 2) with dopamine loss in specific regions of the striatum as measured by [(123)I]FP-CIT SPECT tracer binding to the dopamine transporter (DaT).

RESULTS

Depressive symptoms were related to lower DaT binding in the right caudate nucleus, while motor symptoms were associated with decreased DaT binding in the right putamen. This double dissociation was most pronounced in early-stage PD patients.

CONCLUSIONS

These results suggest that depressive symptoms in PD are associated with dopamine loss in the caudate nucleus, possibly related to degeneration of dopaminergic projections from the ventral tegmental area, while motor symptoms are associated with low dopamine signalling to the putamen and loss of nigrostriatal projections. This is consistent with the neuroanatomy of partially segregated cortical-striatal-thalamocortical circuits and supports the role of dysfunctional associative and motivational circuits in PD-related depression.

Deep brain stimulation improves survival in severe Parkinson's disease

OBJECTIVES

Levodopa and other dopaminergic treatments have not had the expected effect on survival in Parkinson's disease (PD). Bilateral subthalamic nucleus deep brain stimulation (STN-DBS) has been shown to improve motor function, motor fluctuations, health-related quality of life, and to reduce medication usage and drug-induced dyskinesia in patients with severe PD refractory to medical therapy. Little however, has been described on the impact of STN-DBS on the survival of these patients. We aim in this study to examine the impact of STN-DBS on the survival of patients with severe PD.

METHODS

Patients who were eligible for STN-DBS were given the choice of undergoing surgery or continuing on medical treatment. Those who exercised patient choice and preferred to continue with medical treatment formed a control population. All eligible patients seen in a 10-year period are included in this study. Our primary outcome measure is a difference in mortality between the two groups with a secondary measure of admission rates to residential (nursing home) care.

RESULTS

106 patients underwent STN-DBS, and 41 patients exercised patient choice and declined the procedure. The two groups were matched for age, gender, ethnicity, duration of disease, rates of pre-existing depression and Levodopa equivalent doses of anti-Parkinson's medications taken. Patients undergoing STN-DBS had significantly longer survival and were significantly less likely to be admitted to a residential care home than those managed purely medically. The statistical significance of these findings persisted after adjusting for potential confounding factors (survival: p=0.002, HR 0.29 (0.13 to 0.64) (residential care home admission: OR: 0.1 (95% CI 0.0 to 0.3; p<0.001).

INTERPRETATION

We show for the first time that there is a survival advantage of DBS surgery in advanced PD. The effect of potential bias factors is examined. The survival advantage may arise for several postulated reasons, ranging from improvement in axial functions, such as swallowing, to some as yet unrecognised benefit of reduction in dopaminergic medication. These findings are of great interest to both patients with PD and the health professionals considering the treatment options for patients with severe PD.

Extrastriatal dopaminergic changes in Parkinson's disease patients with impulse control disorders

OBJECTIVE

To investigate the extrastriatal dopaminergic neural changes in relation to the medication-related impulse control disorders (ICD) in Parkinson's disease (PD).

METHOD

A total of 31 subjects (11 and 11 drug-treated PD patients with and without medication-related ICDs and 9 healthy controls) having no other co-morbid psychiatric disorders participated in this study. Each subject underwent dynamic N-(3-[(18)F]fluoropropyl)-2-carbomethoxy-3-(4-iodophenyl) nortropane (FP-CIT) positron emission tomography scans. Binding potentials (BP) at nucleus accumbens, amygdala, orbitofrontal and ventromedial prefrontal cortex (VMPFC), putamen and caudate nucleus were estimated, and whole brain parametric maps of [(18)F]-FP-CIT binding were analysed by original and putaminal normalised manners.

RESULTS

Compared with the healthy controls, BPs at both VMPFCs were significantly high and the extrastriatal to putaminal BP ratios at all regions were approximately three times higher in both PD groups. The PD ICD patients showed significantly higher BPs at the right VMPFC and tendency to lower BPs at the left nucleus accumbens compared with those free of ICD. The ICD subjects also showed reduced uptakes at both ventral striatal regions in the original parametric analysis and higher uptakes at the left insular and right posterior cingulate cortex and lower uptakes at both ventral pallidums in the putaminal normalised parametric analysis compared with the non-ICD subjects.

CONCLUSIONS

A great gap in extrastriatal versus striatal dopaminergic fibre degenerations is an intrinsic condition predisposing to ICD in PD. Distinct pattern of extrastriatal changes between the ICD and non-ICD patients could provide a further insight into a mechanism of ICD in PD.

A mitochondrial location for haemoglobins--dynamic distribution in ageing and Parkinson's disease

Haemoglobins are iron-containing proteins that transport oxygen in the blood of most vertebrates. The mitochondrion is the cellular organelle which consumes oxygen in order to synthesise ATP. Mitochondrial dysfunction is implicated in neurodegeneration and ageing. We find that α and β haemoglobin (Hba and Hbb) proteins are altered in their distribution in mitochondrial fractions from degenerating brain. We demonstrate that both Hba and Hbb are co-localised with the mitochondrion in mammalian brain. The precise localisation of the Hbs is within the inner membrane space and associated with inner mitochondrial membrane. Relative mitochondrial to cytoplasmic ratios of Hba and Hbb show changing distributions of these proteins during the process of neurodegeneration in the pcd^5j mouse brain. A significant difference in mitochondrial Hba and Hbb content in the mitochondrial fraction is seen at 31 days after birth, this corresponds to a stage when dynamic neuronal loss is measured to be greatest in the Purkinje Cell Degeneration mouse. We also report changes in mitochondrial Hba and Hbb levels in ageing brain and muscle. Significant differences in mitochondrial Hba and Hbb can be seen when comparing aged brain to muscle, suggesting tissue specific functions of these proteins in the mitochondrion. In muscle there are significant differences between Hba levels in old and young mitochondria. To understand whether the changes detected in mitochondrial Hbs are of clinical significance, we examined Parkinson's disease brain, immunohistochemistry studies suggest that cell bodies in the substantia nigra accumulate mitochondrial Hb. However, western blotting of mitochondrial fractions from PD and control brains indicates significantly less Hb in PD brain mitochondria. One explanation could be a specific loss of cells containing mitochondria loaded with Hb proteins. Our study opens the door to an examination of the role of Hb function, within the context of the mitochondrion—in health and disease.

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Both Hba and Hbb are co-localised with the mitochondrion in mammalian brain.

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Hbs are located in the inter membrane space and inner mitochondrial membrane.

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α and β haemoglobin protein distribution changes with age in brain mitochondria.

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Mitochondrial fractions from PD brains contain significantly less Hb than controls.

Processing of emotional information in the human subthalamic nucleus

BACKGROUND

The subthalamic nucleus (STN) is an efficient target for treating patients with Parkinson's disease as well as patients with obsessive-compulsive disorder (OCD) using high frequency stimulation (HFS). In both Parkinson's disease and OCD patients, STN-HFS can trigger abnormal behaviours, such as hypomania and impulsivity.

METHODS

To investigate if this structure processes emotional information, and whether it depends on motor demands, we recorded subthalamic local field potentials in 16 patients with Parkinson's disease using deep brain stimulation electrodes. Recordings were made with and without dopaminergic treatment while patients performed an emotional categorisation paradigm in which the response varied according to stimulus valence (pleasant, unpleasant and neutral) and to the instruction given (motor, non-motor and passive).

RESULTS

Pleasant, unpleasant and neutral stimuli evoked an event related potential (ERP). Without dopamine medication, ERP amplitudes were significantly larger for unpleasant compared with neutral pictures, whatever the response triggered by the stimuli; and the magnitude of this effect was maximal in the ventral part of the STN. No significant difference in ERP amplitude was observed for pleasant pictures. With dopamine medication, ERP amplitudes were significantly increased for pleasant compared with neutral pictures whatever the response triggered by the stimuli, while ERP amplitudes to unpleasant pictures were not modified.

CONCLUSIONS

These results demonstrate that the ventral part of the STN processes the emotional valence of stimuli independently of the motor context and that dopamine enhances processing of pleasant information. These findings confirm the specific involvement of the STN in emotional processes in human, which may underlie the behavioural changes observed in patients with deep brain stimulation.

Clinical utility of dopamine transporter single photon emission CT (DaT-SPECT) with (123I) ioflupane in diagnosis of parkinsonian syndromes

The diagnosis of movement disorders including Parkinson's disease (PD) and essential tremor is determined through clinical assessment. The difficulty with diagnosis of early PD has been highlighted in several recent clinical trials. Studies have suggested relatively high clinical diagnostic error rates for PD and essential tremor. This review was undertaken to clarify the utility of DaT-SPECT imaging with ((123)I)ioflupane (DaTSCAN or DaTscan or ((123)I)FP-CIT) in assisting practitioners in their clinical decision making by visualising the dopamine transporter in parkinsonian cases. In some patients with suspected parkinsonian syndromes, SPECT imaging with ((123)I)ioflupane is useful to assist in the diagnosis and to help guide prognosis and treatment decisions, including avoiding medications that are unlikely to provide benefit. Clinicians ordering ((123)I)ioflupane SPECT should be aware of its limitations and pitfalls and should order scans when there is diagnostic uncertainty or when the scan will be helpful in clinical decision making.

Zonisamide: a review of the clinical and experimental evidence for its use in Parkinson's disease

The limitations of currently available therapies in addressing the non motor symptoms of Parkinson's disease (PD) have egged on the search for newer options. Zonisamide has been in use for epilepsy and it was serendipitously found to improve the symptoms of PD in a patient who had both epilepsy and PD. Thereafter, various trials were designed to assess the use of zonisamide in PD. The present article investigates the evidence for use of zonisamide in PD from the various clinical trials that were designed to address this issue. Furthermore, the article also summarizes the various mechanisms of its use in PD as described in various animal experiments. A search protocol was designed with predefined inclusion and exclusion criteria. The databases searched were Pubmed, Ovid medline, Cochrane and clinicaltrials.gov. The data thus generated, was fed into a predesigned format. Most of the clinical trials on zonisamide in PD have come from Japan. Most of these trials used the changes in the Unified Parkinson's Disease Rating Scale (UPDRS) score as the endpoints and the most conclusive evidence is for a dose of 25-50 mg, which caused a change in UPDRS part III (motor symptoms). These patients were on levodopa and other drugs used for PD during the trials. One of the clinical trials conducted in Spain investigates the use of zonisamide in impulse control disorders among 15 patients of PD. Among the many mechanisms postulated, a reduction in levodopa induced quinone formation, protection against mitochondrial impairment and an increase in astroglial cysteine transport, an inhibition of microglial activation, monoamine oxidase-B (MAO-B) inhibition, an increased dopamine release and blockade of calcium channels are the most cited. There is evidence for use of zonisamide in PD in addition to levodopa and other therapies for control of motor symptoms. For now, the evidence for its use in control of non motor symptoms in PD is not enough and needs to be investigated further.

A platform for discovery: The University of Pennsylvania Integrated Neurodegenerative Disease Biobank

Neurodegenerative diseases (NDs) are defined by the accumulation of abnormal protein deposits in the central nervous system (CNS), and only neuropathological examination enables a definitive diagnosis. Brain banks and their associated scientific programs have shaped the actual knowledge of NDs, identifying and characterizing the CNS deposits that define new diseases, formulating staging schemes, and establishing correlations between neuropathological changes and clinical features. However, brain banks have evolved to accommodate the banking of biofluids as well as DNA and RNA samples. Moreover, the value of biobanks is greatly enhanced if they link all the multidimensional clinical and laboratory information of each case, which is accomplished, optimally, using systematic and standardized operating procedures, and in the framework of multidisciplinary teams with the support of a flexible and user-friendly database system that facilitates the sharing of information of all the teams in the network. We describe a biobanking system that is a platform for discovery research at the Center for Neurodegenerative Disease Research at the University of Pennsylvania.

BMP-Smad 1/5/8 signalling in the development of the nervous system

The transcription factors, Smad1, Smad5 and Smad8, are the pivotal intracellular effectors of the bone morphogenetic protein (BMP) family of proteins. BMPs and their receptors are expressed in the nervous system (NS) throughout its development. This review focuses on the actions of Smad 1/5/8 in the developing NS. The mechanisms by which these Smad proteins regulate the induction of the neuroectoderm, the central nervous system (CNS) primordium, and finally the neural crest, which gives rise to the peripheral nervous system (PNS), are reviewed herein. We describe how, following neural tube closure, the most dorsal aspect of the tube becomes a signalling centre for BMPs, which directs the pattern of the development of the dorsal spinal cord (SC), through the action of Smad1, Smad5 and Smad8. The direct effects of Smad 1/5/8 signalling on the development of neuronal and non-neuronal cells from various neural progenitor cell populations are then described. Finally, this review discusses the neurodevelopmental abnormalities associated with the knockdown of Smad 1/5/8.

Dysfunction of the locus coeruleus-norepinephrine system and related circuitry in Parkinson's disease-related dementia

Although resting tremor, cogwheel rigidity, hypokinesia/bradykinesia and postural instability usually dominate the clinical picture of sporadic Parkinson's disease (PD), both clinical and epidemiological data reveal that a wide variety of additional symptoms impair patients' quality of life considerably, parallel to the chronic progressive neurodegenerative movement disorder. Autopsy based retrospective studies have shown that α-synuclein immunoreactive Lewy pathology (LP) develops in the locus coeruleus (LC) of patients with neuropathologically confirmed sporadic PD, as well as in individuals with incidental (prodromal or premotor) Lewy body disease but not in age and gender matched controls. Using five case studies, this review discusses the possible role of LP (axonopathy, cellular dysfunction and nerve cell loss) in the LC, catecholaminergic tract and related circuitry in the development of PD-related dementia. The contribution of noradrenergic deficit to cognitive dysfunction in PD has been underappreciated. Noradrenergic therapeutic interventions might not only alleviate depressive symptoms and anxiety but also delay the onset of cognitive decline.

Subthalamic nucleus modulates social and anxogenic-like behaviors

In Parkinson's disease, global social maladjustment and anxiety are frequent after subthalamic nucleus (STN) stimulation and are generally considered to be linked with sociofamilial alterations induced by the motor effects of stimulation. We hypothesized that the STN is per se involved in these changes and aimed to explore the role of STN in social and anxogenic-like behaviors using an animal model. Nineteen male Wistar rats with bilateral lesions of the STN were compared with 26 sham-lesioned rats by synchronizing an ethological approach based upon direct observation of social behaviors and a standardized approach, the elevated plus maze (EPM). Comparisons between groups were performed by a Mann-Whitney-Wilcoxon test. Lesioned rats showed impairments in their social (P=0.05) and aggressive behaviors with a diminution of attacking (P=0.04) and chasing (P=0.06). In the EPM, concerning the open arms, the percentage of distance, time, inactive time, and entry were significantly decreased in lesioned rats (P=0.02, P=0.01, P=0.04, and P=0.05). The time spent in non-protected head dips was also diminished in the lesioned rats (P=0.01). These results strongly implicate the STN in social behavior and anxogenic-like behavior. In human, as DBS induces changes in the underlying dynamics of the stimulated brain networks, it could create an abnormal brain state in which anxiety and social behavior are altered. These results highlight another level of complexity of the behavioral changes after stimulation.

Facial bradykinesia

The aim of this paper is to summarise the main clinical and pathophysiological features of facial bradykinesia in Parkinson's disease (PD) and in atypical parkinsonism. Clinical observation suggests that reduced spontaneous and emotional facial expressions are features of facial bradykinesia in PD and atypical parkinsonism. In atypical parkinsonism, facial bradykinesia is complicated by additional dystonic features. Experimental studies evaluating spontaneous and emotional facial movements demonstrate that PD is characterised by a reduction in spontaneous blinking and emotional facial expression. In PD, neurophysiological studies show that voluntary orofacial movements are smaller in amplitude and slower in velocity. In contrast, movements of the upper face (eg, voluntary blinking) are normal in terms of velocity and amplitude but impaired in terms of switching between the closing and opening phases. In progressive supranuclear palsy (PSP), voluntary blinking is not only characterised by a severely impaired switching between the closing and opening phases of voluntary blinking, but is also slow in comparison with PD. In conclusion, in PD, facial bradykinesia reflects abnormalities of spontaneous, emotional and voluntary facial movements. In PSP, spontaneous and voluntary facial movements are abnormal but experimental studies on emotional facial movements are lacking. Data on facial bradykinesia in other atypical parkinsonism diseases, including multiple system atrophy and corticobasal degeneration, are limited. In PD, facial bradykinesia is primarily mediated by basal ganglia dysfunction whereas in PSP, facial bradykinesia is a consequence of a widespread degeneration involving the basal ganglia, cortical and brainstem structures.

The Val158Met COMT polymorphism is a modifier of the age at onset in Parkinson's disease with a sexual dimorphism

The catechol-O-methyltranferase (COMT) is one of the main enzymes that metabolise dopamine in the brain. The Val158Met polymorphism in the COMT gene (rs4680) causes a trimodal distribution of high (Val/Val), intermediate (Val/Met) and low (Met/Met) enzyme activity. We tested whether the Val158Met polymorphism is a modifier of the age at onset (AAO) in Parkinson's disease (PD). The rs4680 was genotyped in a total of 16 609 subjects from five independent cohorts of European and North American origin (5886 patients with PD and 10 723 healthy controls). The multivariate analysis for comparing PD and control groups was based on a stepwise logistic regression, with gender, age and cohort origin included in the initial model. The multivariate analysis of the AAO was a mixed linear model, with COMT genotype and gender considered as fixed effects and cohort and cohort-gender interaction as random effects. COMT genotype was coded as a quantitative variable, assuming a codominant genetic effect. The distribution of the COMT polymorphism was not significantly different in patients and controls (p=0.22). The Val allele had a significant effect on the AAO with a younger AAO in patients with the Val/Val (57.1±13.9, p=0.03) than the Val/Met (57.4±13.9) and the Met/Met genotypes (58.3±13.5). The difference was greater in men (1.9 years between Val/Val and Met/Met, p=0.007) than in women (0.2 years, p=0.81). Thus, the Val158Met COMT polymorphism is not associated with PD in the Caucasian population but acts as a modifier of the AAO in PD with a sexual dimorphism: the Val allele is associated with a younger AAO in men with idiopathic PD.

Differentiation between idiopathic and atypical parkinsonian syndromes using three-dimensional magnetic resonance spectroscopic imaging

OBJECTIVES

Degeneration of dopaminergic neurons in the substantia nigra (SN) pars compacta is the primary cause of idiopathic Parkinson's disease (iPD). In early stages of disease in particular, presentation of symptoms is non-specific leading to difficulties in differentiating between iPD and atypical parkinsonian syndromes (aPS). The aim of this study was to evaluate the feasibility of three-dimensional magnetic resonance spectroscopic imaging (MRSI) of the SN region for differentiation between iPD and aPS.

METHODS

20 patients with iPD, 10 with aPS and 22 controls were examined on a 3 T MR scanner using three-dimensional MRSI with a voxel size of 0.252 ml and an echo time of 30 ms. Excitation volume was positioned in such a way that in each hemisphere 1 voxel defines the rostral and 1 voxel the caudal SN region. Using a fully automatic spectra evaluation, the metabolite ratios of N-acetyl aspartate/creatine (NAA/Cr) were calculated.

RESULTS

In all cases spectra with good quality were obtained. Differences in rostral to caudal NAA/Cr ratios were significant between controls and iPD patients, as well as between iPD and aPS patients (p<0.001 for both). For controls, rostral NAA/Cr was greater than caudal, whereas in iPD patients this ratio was reversed. aPS patients showed similar ratios as controls.

CONCLUSIONS

Typical reversed rostral to caudal NAA/Cr ratios in iPD patients suggests that they could be linked to specific pathology of neuronal loss in the SN pars compacta. Therefore, the results suggest that MRSI may support the differential diagnosis of patients with clinically unclassifiable parkinsonian syndromes who do not yet fulfil the established clinical criteria.

Neuroprotective activity of Stereospermum suaveolens DC against 6-OHDA induced Parkinson's disease model

OBJECTIVES

To evaluate the neuroprotective effect of Stereospermum suaveolens DC on 6-hydroxy dopamine induced Parkinson's disease model.

MATERIALS AND METHODS

The study was conducted on Sprague-Dawley rats where parkinson's disease was induced by producing the striatal 6-hydroxy dopamine lesions. The test animals received methanolic extract of Stereospermum suaveolens at dose of 125, 250 and 500 mg/kg for 42 days. Behavioral assessment, spontaneous locomotor activity and muscular coordination were studied. Antioxidant levels, striatal infraction area were assessed and histopathological studies were carried out.

RESULTS

The Stereospermum suaveolens DC methanolic extract showed significant dose dependent increase in behavioral activity, improved muscular coordination. Significant reduction of lipid peroxidation (LPO), increased antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT) and non-enzymatic activity of glutathione (GSH) and total thiol levels in extract treated groups was observed in test groups as compared to control group. Striatal infarction area was significantly reduced in extract treated groups as compared to control group.

CONCLUSION

The methanolic extract of Stereospermum suaveolens DC showed neuroprotective activity against 6-hydroxy dopamine induced Parkinson's disease in rats.

Serum 25-hydroxyvitamin D3 concentration in Iranian patients with Parkinson's disease

BACKGROUND

Vitamin D is an important factor responsible for many physiologic functions. Vitamin D deficiency is associated with increased risk of neurodegenerative disease. The level of vitamin D in Iranian patients with Parkinson's disease and its relationship with severity of symptoms and signs were evaluated in this study.

METHODS

Eighty-three patients with Parkinson's disease (PD) were recruited using simple non-random sampling. 25-hydroxyvitamin D [25(OH)D3] was measured by Electrochemiluminescence immunoassay (ECLIA). Serum level of calcium and phosphorus was measured to exclude other endocrine disorders.

RESULTS

The mean 25(OH)D3 concentration was lower in the PD population than in the normal group. Lower levels of 25(OH)D3 were associated with more severe postural instability and abnormal posture. There was no significant association between levels of 25(OH)D3 and severity of other symptoms of parkinsonism.

CONCLUSION

This analysis showed that serum 25(OH)D levels are lower in PD patients in comparison with normal range. In addition, there was a significant association between the presences of freezing, postural instability and abnormal postures with lower levels of 25(OH)D.

Treatment of neurological and psychiatric disorders with deep brain stimulation; raising hopes and future challenges

The technology of Neural Stimulation in recent years has become the focus of the research and treatment, although it has been around for many years. The potential use of stimulating the brain and nerves ranges from the spinal cord stimulation to the implantations of cochlear and bionic eyes with a large discrepancy between the clinical readiness for these various uses. Electrical high-frequency Deep Brain Stimulation (DBS) was developed as an alternative option to treat a few neurological disorders. However, with advancing in surgical procedures, technologies and safeties, the applications of DBS are expanding not only for therapeutic purposes but also for research. Although the exact mechanisms of action/s are not fully understood, the outcome of the ongoing research and clinical trials are promising. DBS has been used to treat the essential tremor since 1997, Parkinson's disease (PD) since 2002 and dystonia since 2003. It has also been used to treat various disorders, including major depression. The therapeutic effect of DBS in PD is well established but for other diseases such as epilepsy the outcomes are unclear and ambiguous. This article is a succinct review of the literature, focusing on PD, epilepsy and Obsessive Compulsive Disorder (OCD).

Cognitive impairments in Parkinson's disease: Evidence from an Iranian population

BACKGROUND

Patients with Parkinson's disease (PD) have different cognitive impairments. The goal of this study is the analysis of these changes in the mentioned patients.

METHODS

A cross-sectional study was performed on 87 patients with PD. Patients were given a questionnaire to gather data about their medical and living statuses. To assess cognitive assessment, SCOPA-COG (Scales for Outcome in Parkinson Cognition) was used by an expert cognitive neuroscientist.

RESULTS

The age inversely correlated to memory and learning (P < 0.01). Education level correlated directly to attention, memory, learning, executive function and visuospatial function (for all items P < 0.001). Spouse relationship type showed inverse association with memory, learning, executive function and visuospatial function (P < 0.05).

CONCLUSION

Cognitive domains in PD patients may be under the influence of different factors. Due to the lack of control group in this study, cautious interpretation of findings is needed.

REM sleep behavior disorder in the marmoset MPTP model of early Parkinson disease

STUDY OBJECTIVES

Sleep problems are a common phenomenon in most neurological and psychiatric diseases. In Parkinson disease (PD), for instance, sleep problems may be the most common and burdensome non-motor symptoms in addition to the well-described classical motor symptoms. Since sleep disturbances generally become apparent in the disease before motor symptoms emerge, they may represent early diagnostic tools and a means to investigate early mechanisms in PD onset. The sleep disturbance, REM sleep behavior disorder (RBD), precedes PD in one-third of patients. We therefore investigated sleep changes in marmoset monkeys treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP), the non-human primate model for idiopathic PD.

DESIGN

Mild parkinsonism was induced in 5 marmoset monkeys (3M/2F) over a 2-week period of subchronic MPTP treatment. Electroencephalograms (EEGs) and electromyograms (EMGs) were recorded weekly. Motor activity and hand-eye coordination were also measured weekly, and any signs of parkinsonism were noted each day. Sleep parameters, motor activity, and performance data before and after MPTP treatment were compared between MPTP-treated marmosets and 4 control marmosets (1M/3F).

RESULTS

MPTP increased the number of sleep epochs with high-amplitude EMG bouts during REM sleep relative to control animals (mean ± SEM percentage of REM 58.2 ± 9.3 vs. 29.6 ± 7.7; P < 0.05). Of all sleep parameters measured, RBD-like measures discriminated best between MPTP-treated and control animals. On the other hand, functional motor behavior, as measured by hand-eye coordination, was not affected by MPTP treatment (correct trials MPTP: 23.40 ± 3.56 vs. control: 36.13 ± 5.88 correct trials; P = 0.32).

CONCLUSIONS

This REM sleep-specific change, in the absence of profound changes in wake motor behaviors, suggests that the MPTP marmoset model of PD could be used for further studies into the mechanisms and treatment of RBD and other sleep disorders in premotor symptom PD.

Demographic study of parkinson's disease in Iran: Data on 1656 cases

BACKGROUND

There is no documented demographical study on Iranian Parkinson's disease (PD) patients, so this study was conducted to identify demographic information about patients with PD in Iran, and to explore demographical differences between PD patients in Iran and other countries.

METHODS

We reviewed medical records of 1656 patients diagnosed with PD, who referred from all parts of Iran to a referral Parkinson's disease clinic in Tehran. We collected data about their age, gender, age of onset, side of motor symptoms' onset, and drug history.

RESULTS

This study was performed on 1656 patients with idiopathic Parkinson's disease, and the results showed that, out of 1656 cases, 1132 patients were males (68.4%) and 524 patients were females (31.6%). The mean age of these patients was 65.16 ±11.9 years (16-99 years). The mean age of onset in these patients was 53.16 ±12.5 years (12-90 years). Among 697 patients, 345 patients (49.5%) had right onset PD, and the remaining 352 cases had left onset PD (50.5%). Side of motor symptoms onset was not associated with the age of the patients at disease onset (P > 0.05). The incidence of right onset PD in males was 50.1% and 48.2% in females, although this difference was not statistically significant (P > 0.05). There was no significant difference between males and females in age of onset (P > 0.05).

CONCLUSION

Our data suggests that the male to female ratio among Iranian Parkinson's disease patients is much higher than other countries. Additional investigation is required in this field.