Diagnosis of vascular parkinsonism: A new tool for gait hypokinesia occurring in older persons

INTRODUCTION

Reliable diagnosis of vascular parkinsonism (VaP) in the presence of a gait hypokinesia is an issue that is encountered in geriatrics. The EVAMAR-AGEX study was focusing on the phenomenon of recurrent falls in older persons (OP) with this parkinsonian gait. The present study is focusing on the diagnosis of VaP-related parkinsonian gait by developing a diagnostic guidance model adapted to OP.

METHODS

Data from baseline and the 2-year follow-up visit were used to carry out univariate analysis and calculation of odds ratios, allowing to identify relevant variables to include in the diagnostic guidance model. To evaluate the model, confusion matrices were created, evaluating true positive, false negative, false positive and true negative incidences, sensitivity and specificity, and negative and positive predictive values.

RESULTS

79 patients included 58% male; average age 81.24 years. VaP diagnosis according to Zijlmans criteria occurred in 28%; neurodegenerative parkinsonian syndromes in 72%. A 4-criteria model was established to facilitate diagnostic: lack of prior hallucinations, lack of movement disorders tremor excluded, no cognitive fluctuations, and ≥75 years of age at diagnosis. In combination of 4/4 criteria, all of them were required to disclose a specificity of 91% in the diagnosis of VaP. In combination of 3/4, in case of negative test, a negative predictive value for VaP diagnosis of 0.97 was obtained.

CONCLUSION

The challenge of our tool is both to be able to rule out what is probably not a VaP and to argue what makes a VaP diagnosis probable in OP.

Ginsenoside Rg3 exerts a neuroprotective effect in rotenone-induced Parkinson's disease mice via its anti-oxidative properties

Ginsenoside Rg3, extracted from Panax ginseng C.A. Meyer, has been shown to possess neuroprotective properties. The present study aims to investigate the neuroprotective effects of ginsenoside Rg3 on rotenone-induced Parkinson's disease mice. Rotenone, a mitochondrial complex I inhibitor, leads to the augmentation of reactive oxygen species production in cells. Male C57/BL6 mice were intragastrically administered rotenone (30 mg/kg) and then treated with ginsenoside Rg3 (5, 10, or 20 mg/kg). Pole, rotarod, and open field tests were performed to evaluate motor function. Ginsenoside Rg3 decreased the climbing time in the pole test (p < 0.01), whereas it increased the latency in the rotarod test (p < 0.01) and the total distance (p < 0.01) and mean speed in the open field test (p < 0.01). Ginsenoside Rg3 treatment augmented the number of tyrosine hydroxylase-positive neurons in the substantia nigra (p < 0.01), mean density of tyrosine hydroxylase-positive nerve fibers (p < 0.01), and dopamine content (p < 0.01) in the striatum and reduced the reactive oxygen species level in the substantia nigra (p < 0.01). Glutathione cysteine ligase regulatory subunit and glutathione cysteine ligase modulatory subunit expression levels were elevated in the ginsenoside Rg3 groups. Ginsenoside Rg3 also improved motor function in rotenone-induced Parkinson's disease mice. The neuroprotective effects of ginsenoside Rg3 are at least partly associated with its anti-oxidative properties via regulation of glutathione cysteine ligase modulatory subunit and glutathione cysteine ligase regulatory subunit expression.

Cascading from SARS-CoV-2 to Parkinson's Disease through Protein-Protein Interactions

Extensive extrapulmonary damages in a dozen of organs/systems, including the central nervous system (CNS), are reported in patients of the coronavirus disease 2019 (COVID-19). Three cases of Parkinson's disease (PD) have been reported as a direct consequence of COVID-19. In spite of the scarce data for establishing a definitive link between COVID-19 and PD, some hypotheses have been proposed to explain the cases reported. They, however, do not fit well with the clinical findings reported for COVID-19 patients, in general, and for the PD cases reported, in particular. Given the importance of this potential connection, we present here a molecular-level mechanistic hypothesis that explains well these findings and will serve to explore the potential CNS damage in COVID-19 patients. The model explaining the cascade effects from COVID-19 to CNS is developed by using bioinformatic tools. It includes the post-translational modification of host proteins in the lungs by viral proteins, the transport of modified host proteins via exosomes out the lungs, and the disruption of protein-protein interaction in the CNS by these modified host proteins. Our hypothesis is supported by finding 44 proteins significantly expressed in the CNS which are associated with PD and whose interactions can be perturbed by 24 host proteins significantly expressed in the lungs. These 24 perturbators are found to interact with viral proteins and to form part of the cargoes of exosomes in human tissues. The joint set of perturbators and PD-vulnerable proteins form a tightly connected network with significantly more connections than expected by selecting a random cluster of proteins of similar size from the human proteome. The molecular-level mechanistic hypothesis presented here provides several routes for the cascading of effects from the lungs of COVID-19 patients to PD. In particular, the disruption of autophagy/ubiquitination processes appears as an important mechanism that triggers the generation of large amounts of exosomes containing perturbators in their cargo, which would insult several PD-vulnerable proteins, potentially triggering Parkinsonism in COVID-19 patients.

Evaluation of 18F-IAM6067 as a sigma-1 receptor PET tracer for neurodegeneration in vivo in rodents and in human tissue

The sigma 1 receptor (S1R) is widely expressed in the CNS and is mainly located on the endoplasmic reticulum. The S1R is involved in the regulation of many neurotransmission systems and, indirectly, in neurodegenerative diseases. The S1R may therefore represent an interesting neuronal biomarker in neurodegenerative diseases such as Parkinson's (PD) or Alzheimer's diseases (AD). Here we present the characterisation of the S1R-specific 18F-labelled tracer 18F-IAM6067 in two animal models and in human brain tissue. Methods: Wistar rats were used for PET-CT imaging (60 min dynamic acquisition) and metabolite analysis (1, 2, 5, 10, 20, 60 min post-injection). To verify in vivo selectivity, haloperidol, BD1047 (S1R ligand), CM398 (S2R ligand) and SB206553 (5HT2B/C antagonist) were administrated for pre-saturation studies. Excitotoxic lesions induced by intra-striatal injection of AMPA were also imaged by 18F-IAM6067 PET-CT to test the sensitivity of the methods in a well-established model of neuronal loss. Tracer brain uptake was also verified by autoradiography in rats and in a mouse model of PD (intrastriatal 6-hydroxydopamine (6-OHDA) unilateral lesion). Finally, human cortical binding was investigated by autoradiography in three groups of subjects (control subjects with Braak ≤2, and AD patients, Braak >2 & ≤4 and Braak >4 stages). Results: We demonstrate that despite rapid peripheral metabolism of 18F-IAM6067, radiolabelled metabolites were hardly detected in brain samples. Brain uptake of 18F-IAM6067 showed differences in S1R anatomical distribution, namely from high to low uptake: pons-raphe, thalamus medio-dorsal, substantia nigra, hypothalamus, cerebellum, cortical areas and striatum. Pre-saturation studies showed 79-90% blockade of the binding in all areas of the brain indicated above except with the 5HT2B/C antagonist SB206553 and S2R ligand CM398 which induced no significant blockade, indicating good specificity of 18F-IAM6067 for S1Rs. No difference between ipsi- and contralateral sides of the brain in the mouse model of PD was detected. AMPA lesion induced a significant 69% decrease in 18F-IAM6067 uptake in the globus pallidus matching the neuronal loss as measured by NeuN, but only a trend to decrease (-16%) in the caudate putamen despite a significant 91% decrease in neuronal count. Moreover, no difference in the human cortical binding was shown between AD groups and controls. Conclusion: This work shows that 18F-IAM6067 is a specific and selective S1R radiotracer. The absence or small changes in S1R detected here in animal models and human tissue warrants further investigations and suggests that S1R might not be the anticipated ideal biomarker for neuronal loss in neurodegenerative diseases such as AD and PD.

Acrolein-mediated alpha-synuclein pathology involvement in the early post-injury pathogenesis of mild blast-induced Parkinsonian neurodegeneration

Survivors of blast-induced traumatic brain injury (bTBI) have increased susceptibility to Parkinson's disease (PD), characterized by α-synuclein aggregation and the progressive degeneration of nigrostriatal dopaminergic neurons. Using an established bTBI rat model, we evaluated the changes of α-synuclein and tyrosine hydroxylase (TH), known hallmarks of PD, and acrolein, a reactive aldehyde and marker of oxidative stress, with the aim of revealing key pathways leading to PD post-bTBI. Indicated in both animal models of PD and TBI, acrolein is likely a point of pathogenic convergence. Here we show that after a single mild bTBI, acrolein is elevated up to a week, systemically in urine, and in whole brain tissue, specifically the substantia nigra and striatum. Acrolein elevation is accompanied by heightened α-synuclein oligomerization, dopaminergic dysregulation, and acrolein/α-synuclein interaction in the same brain regions. We further show that acrolein can directly modify and oligomerize α-synuclein in vitro. Taken together, our data suggests acrolein likely plays an important role in inducing PD pathology following bTBI by encouraging α-synuclein aggregation. These results are expected to advance our understanding of the long-term post-bTBI pathological changes leading to the development of PD, and suggest intervention targets to curtail such pathology.

Effect of phenothiazine compounds on the secondary structure and fibrillogenesis of poly-l-lysine

Phenothiazine molecules are effective and commonly used antipsychotic drugs, especially in the treatment of schizophrenia. However, they produce strong extrapyramidal side-effects manifested by drug-induced parkinsonism. Because Parkinson's disease as a neurodegenerative illness is associated with the formation of amyloid fibrils in neuronal cells, it is postulated that the development of phenothiazine-induced parkinsonism may be related to the phenothiazine-induced formation of fibrillar aggregates. The effect of phenothiazine compounds (fluphenazine (FPh), chlorpromazine (ChP) and propionylpromazine (PP)) on the fibrillogenesis of poly-l-lysine (PLL) was studied using Fourier-transform infrared (FTIR) spectroscopy supported by principal component analysis (PCA), vibrational circular dichroism (VCD), transmission electron microscopy (TEM) and Congo red binding assay. The fibrillogenesis of PLL is accompanied by fibril formation with charged or uncharged polypeptides with PPII (polyproline-like extended helix), α-helix or β-sheet conformations. All of the phenothiazine molecules investigated effectively reduced the temperature required to induce the formation of β-sheet-rich fibrils from α-helix-rich fibrils of PLL.

Pinostrobin Exerts Neuroprotective Actions in Neurotoxin-Induced Parkinson's Disease Models through Nrf2 Induction

The aim of the present study was to assess the neuroprotective effects of pinostrobin (PSB), a dietary bioflavonoid, and its underlying mechanisms in neurotoxin-induced Parkinson's disease (PD) models. First, PSB could attenuate 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced loss of dopaminergic neurons and improve behavior deficiency in zebrafish, supporting its potential neuroprotective actions in vivo. Next, PSB could decreased apoptosis and death in the 1-methyl-4-phenylpyridinium (MPP⁺)-intoxicated SH-SY5Y cells, evidenced by MTT, LDH, Annexin V-FITC/PI, and DNA fragmentation assay. PSB also blocked MPP⁺-induced apoptotic cascades, including loss of mitochondrial membrane potential, activation of caspase 3, and reduced ratio of Bcl-2/Bax. In addition, PSB suppressed MPP⁺-induced oxidative stress but increased antioxidant enzymes, evidenced by decrease of reactive oxygen species generation and lipid peroxidation and up-regulation of GSH-Px, SOD, CAT, GSH/GSSG, and NAD/NADH. Further investigations showed that PSB significantly enhanced Nrf2 expression and nuclear accumulation, improved ARE promoter activity and up-regulated expression of HO-1 and GCLC. Furthermore, Nrf2 knockdown via specific Nrf2 siRNA abolished PSB-induced antioxidative and antiapoptotic effects against MPP⁺ insults. Interestingly, we then found that PSB promoted phosphorylation of PI3K/AKT and ERK, and pharmacological inhibition of PI3K/AKT or ERK signaling diminished PSB-induced Nrf2/ARE activation and protective actions. In summary, PSB confers neuroprotection against MPTP/MPP⁺-induced neurotoxicity in PD models. Promoting activation of Nrf2/ARE signaling contributes to PSB-mediated antioxidative and neuroprotective actions, which, in part, is mediated by PI3K/AKT and ERK.

The relationship of leukoaraiosis and the clinical severity of vascular Parkinsonism

Vascular Parkinsonism (VP) is referred to as secondary Parkinsonian syndrome. It occurs with lacunar state or sub-cortical white matter micro-angiopathy and is highly associated with vascular risk factors and leukoaraiosis, also known as cerebral white matter lesions (WML). This study aimed to assess the prevalence of different vascular risk factors and WML in patients with VP, and their impact on clinical features. Sixty-two consecutive VP patients (70.2 ± 9.2 years) were evaluated for clinical severity using the Unified Parkinson's Disease Rating Scale (UPDRS). WML was assessed and scored on fluid-attenuated inversion recovery T2-weighted (FLAIR) magnetic resonance imaging (MRI). Cerebro-vascular risk factors, WML severity, and the UPDRS for clinical disability were analyzed statistically. There were no associations between WML score and age, sex, hypertension, diabetes, previous stroke, cardiac disease, cigarette smoking, or serum levels of cholesterol and triglyceride. The WML score positively correlated with UPDRS part I (p = 0.035) and part III (p = 0.041) scores. After adjustments for age, gender, stroke history, and use of levodopa, the WML score was associated with the UPDRS total (p = 0.020), part I (p = 0.012), part II (p = 0.039), and part III (p = 0.019) scores. The severity of WML is not associated with conventional vascular risk factors in VP patients but is significantly correlated with the UPDRS total and all sub-scores, which suggests that disruption of the cortico-sub-cortical circuits may lead to impaired mentation, behavior and mood, activities of daily living, and motor performance in these patients.

Antidepressants and REM sleep behavior disorder: isolated side effect or neurodegenerative signal?

OBJECTIVES

Antidepressants, among the most commonly prescribed medications, trigger symptoms of REM sleep behavior disorder (RBD) in up to 6% of users. Idiopathic RBD is a very strong prodromal marker of Parkinson disease and other synuclein-mediated neurodegenerative syndromes. It is therefore critically important to understand whether antidepressant-associated RBD is an independent pharmacologic syndrome or a sign of possible prodromal neurodegeneration.

DESIGN

Prospective cohort study.

SETTING

Tertiary sleep disorders center.

PARTICIPANTS

100 patients with idiopathic RBD, all with diagnosis confirmed on polysomnography, stratified to baseline antidepressant use, with 45 matched controls.

MEASUREMENTS/RESULTS

Of 100 patients, 27 were taking antidepressants. Compared to matched controls, RBD patients taking antidepressants demonstrated significant abnormalities of 12/14 neurodegenerative markers tested, including olfaction (P = 0.007), color vision (P = 0.004), Unified Parkinson Disease Rating Scale II and III (P < 0.001 and 0.007), timed up-and-go (P = 0.003), alternate tap test (P = 0.002), Purdue Pegboard (P = 0.007), systolic blood pressure drop (P = 0.029), erectile dysfunction (P = 0.002), constipation (P = 0.003), depression indices (P < 0.001), and prevalence of mild cognitive impairment (13% vs. 60%, P < 0.001). All these abnormalities were indistinguishable in severity from RBD patients not taking antidepressants. However, on prospective follow-up, RBD patients taking antidepressants had a lower risk of developing neurodegenerative disease than those without antidepressant use (5-year risk = 22% vs. 59%, RR = 0.22, 95%CI = 0.06, 0.74).

CONCLUSIONS

Although patients with antidepressant-associated RBD have a lower risk of neurodegeneration than patients with "purely-idiopathic" RBD, markers of prodromal neurodegeneration are still clearly present. Development of RBD with antidepressants can be an early signal of an underlying neurodegenerative disease.

Do α-synuclein vector injections provide a better model of Parkinson's disease than the classic 6-hydroxydopamine model?

Improvements in modelling Parkinson's disease in rodents contribute to the advancement of scientific knowledge and open innumerable pathways for the development of new therapeutic interventions. In a recent article in this journal, Decressac and co-workers present an interesting comparison between two classic 6-hydroxydopamine (6-OHDA) models and the more recently established rodent model of Parkinson's disease induced by over-expression of α-synuclein using adeno-associated viral vectors. As expected, injections of 6-OHDA result in extensive loss of dopamine associated with pronounced motor deficits. Interestingly, over-expression of α-synuclein in the substantia nigra pars compacta also results in a considerable loss of dopamine as well as motor impairments. Both the level of dopamine loss and the motor deficits seen after α-synuclein over-expression were similar in extent to that seen after intrastriatal injections of 6-OHDA, but the temporal profile of degeneration and the development of motor deficits were progressive, more closely mimicking the clinical condition. This commentary offers further insights into the differences between these two rodent models, and asks how well they each replicate idiopathic PD. In addition, the translational relevance, reliability, and predictive value of this more recently developed AAV α-synuclein model are considered.

Use of non-steroidal anti-inflammatory drugs and risk of Parkinson's disease: nested case-control study

OBJECTIVE

To evaluate the relation between Parkinson's disease and prior use of non-steroidal anti-inflammatory drugs (NSAIDs) in a large cohort of men.

DESIGN

Case-control analysis nested in the Physicians' Health Study.

PARTICIPANTS

22,007 male physicians aged 40-84 years without indications for or contraindications to regular NSAID use and free of Parkinson's disease at baseline. Cases and controls were matched by age alone or by age and scores for confounders (comorbidity and indicators of NSAID use). Up to five controls were matched to each of 616 cases by age and 565 cases by age and confounder scores.

SETTING

United States.

MAIN OUTCOME MEASURES

Odds of having been exposed to prior non-aspirin NSAID or aspirin use by participants with Parkinson's disease and by their controls in each case-control set.

RESULTS

Participants who had ever used non-aspirin NSAIDs had an increased risk of Parkinson's disease (odds ratio 1.28 (95% CI 1.05 to 1.56) in the age matched group but not in the group also matched on confounder scores (odds ratio 1.17 (0.94 to 1.46)). There was an increased risk of Parkinson's disease in men who had 1-2 years of regular non-aspirin NSAID use (odds ratio 1.35 (1.07 to 1.70)), a finding that remained significant after matching for confounder scores as well (odds ratio 1.35 (1.05 to 1.75)). In contrast, the significant association of use of non-aspirin NSAIDs for ≥ 5 years (odds ratio 1.48 (1.05 to 2.09)) in the age matched group was entirely attenuated in the group also matched on confounder scores (1.03 (0.70 to 1.53)). There was also a suggestion that men who regularly used aspirin had an increased risk of Parkinson's disease. Positive associations between non-aspirin NSAID or aspirin and risk of Parkinson's disease tended to disappear when analyses were limited to drug use ≥ 5 years before the disease diagnosis.

CONCLUSIONS

This case-control study did not find evidence that NSAID use reduces Parkinson's disease risk. The positive associations observed between NSAID use and Parkinson's disease might have been due to confounding by indication as the use was clustered in the few years before disease diagnosis.

Dopamine transporter binding is unaffected by L-DOPA administration in normal and MPTP-treated monkeys

Background

Radiotracer imaging of the presynaptic nigrostriatal dopaminergic system is used to assess disease progression in Parkinson's disease (PD) and may provide a useful adjunct to clinical assessment during therapeutic trials of potential neuroprotective agents. Several clinical trials comparing dopamine agonists to L-DOPA or early vs. late L-DOPA have revealed differences between clinical assessment and imaging of the presynaptic dopaminergic system, hence questioning the comparability of these measures as neuroprotection outcome variables. Thus, results of these studies may have been affected by factors other than the primary biological process investigated.

Methodology/Principal Findings

We tested the possibility that L-DOPA might interfere with DAT binding. Post-mortem DAT binding was conducted in normal and MPTP-treated macaque monkeys that were administered L-DOPA, acutely or chronically. In parallel, DAT SPECT was conducted in MPTP-treated animals that were administered chronic L-DOPA. [99mTc]TRODAT-1 SPECT binding was similarly reduced in all MPTP monkeys regardless of L-DOPA treatment. L-DOPA had no significant effect on post-mortem DAT binding either in saline or in MPTP-lesioned animals.

Conclusions/Significance

These data indicate that L-DOPA does not induce modifications of DAT expression detectable by SPECT of by DAT binding autoradiography, suggesting that differences between clinical assessment and radiotracer imaging in clinical trials may not be specifically related to L-DOPA treatment.

[Study of extracellular concentration of dopamine and its metabolites in mice striatum by a microdialysis technique at intraperitoneal administration of MPTP]

In this paper a structure of a microdialytic cannula inserted into brain areas just before a microdialysis is described. The cannula used allowed to find out a correspondence of behavioral and biochemical changes in C57BL/6 mice at various time intervals after a single dose administration (20 mg/kg) of the neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, without any additional pharmacological actions enhancing an extracellular striatal dopamine concentration. Immediately after 1-methyl-4-phenyl-1.2,3.6-tetrahydropyridine administration an essential disturbance of mice behavior and a significant reduction of the extracellular concentration of dopamine and homovanillic acid were observed in striatum. A week after the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine administration neither behavior nor the extracellular dopamine and homovanillic acid striatal concentration substantially differed from those of controls. 30 days after the neurotoxin administration there was again an essential disturbance of behavior and the large reduction of dopamine and its metabolite concentration in striatum. There was suggested that a reduction of the dopamine concentration immediately after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine injection connected with abnormalities of dopamine synthesis and metabolism induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine whereas a reduction of the extracellular striatal dopamine concentration 30 days after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine administration related to damage of the nigrastriatal dopaminergic system.

A patient with parkinsonism related to Gaucher's disease type I successfully treated by unilateral pallidotomy - a 3-year follow-up

Gaucher's disease is the most common hereditary lysosomal storage disorder and presents with a wide clinical spectrum including parkinsonism. We present a patient first diagnosed with idiopathic Parkinson's disease at the age of 38 due to left-sided bradykinesia and rigidity. But thereafter the diagnosis of Gaucher's disease type I according to clinical pictures and clinical genetic testing was made. Despite the optimal enzyme replacement therapy, the parkinsonian symptoms worsened. He was referred for consideration for surgical treatment of his severe parkinsonism. At the age of 54 he underwent right-sided posteroventrolateral pallidotomy. The surgery was uneventful and he immediately improved. On the last examination performed 3 years later, he had mild parkinsonism and was independent in all activities of daily living. This case demonstrates a benefit of surgical treatment for genetically proven Gaucher's disease type I.

Parkinsonian syndrome associated with subacute subdural haematoma and its effective surgical treatment: a case report

There have been several reports of parkinsonian syndrome arising from a mass effect from subdural haematomas. In this study, we present a case of parkinsonian syndrome caused by a subacute subdural haematoma. Evacuation of the haematoma resulted in the disappearance of parkinsonian symptoms in this case. Parkinsonism is not common complication of subdural haematoma; surgical treatment of those cases is associated with favourable outcome, without the need for antiparkinsonian medication.

Could Parkinsonism complicate craniotomy and excision of convexity meningioma? A case report

Parkinsonism is a neurodegenerative clinical disorder characterized by varying combinations and degrees of rest tremor, rigidity, slowing of voluntary movements and postural instability. Amongst the aetiologic factors, massive post-craniotormy haematoma has not been previously considered. This report is to arouse the suspicion that vascular displacement in the midbrain resulting from a massive unilateral intracranial haematoma could lead to the unusual complication of Parkinsonism. This is the report of a 55-year old retired male banker, without any previously identifiable risk factor except for his age, who developed Parkinsonism following a huge acute extradural haematoma that complicated a craniotomy for the excision of a haemorrhagic convexity meningioma. The patient was placed on medical treatment resulting in a slow but progressive neurological improvement. Reports of Parkinsonism following post-tumour excision are probably, very rare. We, hereby, report a case of Parkinsonism complicating a gross total excision of a convexity meningioma.

Effects of disease duration on the clinical features and brain glucose metabolism in patients with mixed type multiple system atrophy

To study the effect of disease duration on the clinical, neuropsychological and [(18)F]-deoxyglucose (FDG) PET findings in patients with mixed type multiple system atrophy (MSA), this study included 16 controls and 37 mixed-type MSA patients with a shorter than a 3-year history of cerebellar or parkinsonian symptoms. We classified the patients into three groups according to the duration of parkinsonian or cerebellar symptoms (Group I = <or=1 year; II = 13-24 months; III = 25-36 months). We performed UPDRS, international cooperative ataxia rating scale (ICARS), and a neuropsychological test battery. We compared the FDG PET findings of each group of patients with controls. Group I patients frequently had memory and frontal executive dysfunction. They showed hypometabolism in the frontal cortex, anterior cerebellar hemisphere and vermis. They had parkinsonian motor deficits, but no basal ganglia hypometabolism. Group II and III patients frequently had multiple domain cognitive impairments, and showed hypometabolism in the frontal and parieto-temporal cortices. Hypometabolism of the bilateral caudate and the left posterolateral putamen was observed in Group II, and whole striatum in Group III. In summary, the cortical hypometabolism begins in the frontal cortex and spreads to the parieto-temporal cortex in MSA. This spreading pattern coincides with the progressive cognitive decline. Early caudate hypometabolism may also contribute to the cognitive impairment. Parkinsonian motor deficits precede putaminal hypometabolism that begins in its posterolateral part. Cerebellar hypometabolism occurs early in the clinical courses and seems to be a relevant metabolic descriptor of cerebellar deficits.

Alpha-synuclein and its role in metal binding: Relevance to Parkinson's disease

Parkinson's disease and some other neurodegenerative disorders are associated with a protein that can aggregate and form fibrils called alpha-synuclein. Like many other proteins associated with neurodegenerative disorders, this protein has no known function, and the mechanism by which it could cause diseases is poorly defined. It was recently suggested that it binds copper. This review assesses what is known about alpha-synuclein and its interaction with metals.

[Hemiparkinsonism secondary to mesencephalic bleeding]

Vascular parkinsonism is the second cause of secondary parkinsonism, and can cause a complex clinical syndrome. In spite of this, it is not common to find an isolated vascular injury in the mesencephalic region, and even rarer for it to give rise to clinical parkinsonism. We present the case of a young patient who developed left hemiparkinsonism with a fluctuating clinical evolution and unpredictable response to the treatment after suffering right mesencephalic bleeding. Structural and functional neuroimaging techniques showed injury on the mesencephalic level and no uptake in the right striatal region, respectively.

Lower striatal dopamine transporter binding in neuroleptic-naive schizophrenic patients is not related to antipsychotic treatment but it suggests an illness trait

INTRODUCTION

Drug induced parkinsonism (DIP) is directly related to dopamine D2 receptor blockade. However, there are many references describing parkinsonian signs (PS) in naive-patients. In our previous study, we observed lower DAT binding in a group of first-episode schizophrenic patients after short-term treatment with risperidone, compared with age-matched healthy controls.

AIM

To clarify if DAT decrease could be an illness trait, excluding the effect of antipsychotics on DAT availability, and to determine whether DAT availability before treatment with antipsychotics may predict subsequent development of PS.

MATERIALS AND METHODS

A new series of 20 neuroleptic-naive schizophrenic patients and 15 healthy subjects was recruited. SPECT with [(123)I] FP-CIT (DaTSCAN(R)) was performed before starting antipsychotics and after 4 weeks of treatment. PS and psychopathological status were assessed by the Simpson-Angus (SAS), CGI and PANSS scales. Quantitative analyses of SPECTs were performed using ROIs placed in the caudate, putamen and occipital cortex.

RESULTS

Schizophrenic patients showed lower DAT binding compared with the healthy subjects at baseline (p<0.001) and after a 4-week-treatment period (p=0.001). Six out of eight schizophrenic patients of the DIP group were symptomatic for PS at baseline, in comparison to two out of 12 in the NoDIP group. Nonetheless, no differences were observed on DAT between DIP and NoDIP, neither at baseline (p=0.360) nor at endpoint (p=0.984). Finally, no differences between baseline-endpoint DAT binding were observed, neither in the DIP group (p=0.767) nor in the NoDIP group (p=0.093).

CONCLUSION

Our new series of first-episode naive-schizophrenic patients (1) points out DAT dysfunction as an illness trait due to the significantly lower DAT binding in schizophrenic patients in comparison to healthy subjects; (2) supports the results of other authors who describe PS in never-treated patients; (3) confirms that [(123)I] FP-CIT does not allow us to predict which patients will develop parkinsonism due to the lack of differences between DIP and NoDIP patients; and (4) confirms a null effect of antipsychotics on DAT due to the lack of differences in [(123)I] FP-CIT before and after a 4-week-treatment period.

Pyramidal tract degeneration in multiple system atrophy: the relevance of magnetization transfer imaging

The clinical features of multiple system atrophy (MSA) include four domains: autonomic failure/urinary dysfunction, Parkinsonism, cerebellar ataxia, and corticospinal tract dysfunction. Although the diagnosis of definite MSA requires pathological confirmation, magnetic resonance imaging (MRI) studies have been shown to contribute to the diagnosis of MSA. Although pyramidal tract dysfunction is frequent in MSA patients, signs of pyramidal tract involvement are controversially demonstrated by MRI. We evaluated the pyramidal involvement in 10 patients (7 women) with clinically probable MSA, detecting the presence of spasticity, hyperreflexia, and Babinski sign, as well as demonstrating degeneration of the pyramidal tract and primary motor cortex by MRI in all of them. Our article also discusses key radiological features of this syndrome. In MSA, pyramidal tract involvement seems to be more frequent than previously thought, and the clinicoradiological correlation between pyramidal tract dysfunction and degeneration may contribute to the understanding of the clinical hallmarks of MSA. MRI may also add information regarding the differential diagnosis of this syndrome.

Neuroimaging of bilateral caudate infarction manifesting as Parkinsonian gait disorder

Neurobehavioral changes characterize the clinical presentation of bilateral caudate infarction. We describe an 82-year-old man who presented with a Parkinsonian gait disorder in the absence of behavioral abnormality whose diffusion-weighted imaging demonstrated infarction of the caudate nuclei.

Predictors of neuroleptic-induced dyskinesia and parkinsonism: the influence of measurement methods and definitions

The accurate and objective measurement of abnormal, involuntary movements remains highly desirable, whether the movements are secondary to pharmacotherapy or an expression of the primary illness. In a previous study, we found that the prevalence of tardive dyskinesia in a sample of 100 subjects ranged from 28% when using the Abnormal Involuntary Movement Scale (AIMS) or the Dyskinesia Identification Scale, Condensed User Version (DISCUS) to 62% using an instrumental measurement (IM) of peripheral dyskinesia. The goal of this study was to examine the relationship between various risk factors for tardive dyskinesia as predictor variables, and the AIMS, DISCUS, and IMs of dyskinesia, tremor, and velocity of motor movement as dependent variables. The sample consisted of 100, mostly patients with schizophrenia. Poor performance on the Mini-Mental State Examination (MMSE) and increasing age were the most consistent predictors of dyskinetic and parkinsonian movements. Various predictors were associated with specific abnormal movements. Head injury was related to slower speed of motor movements and the total DISCUS score. A history of smoking was associated with less IM dyskinesia. For those with coexisting parkinsonism and dyskinesia, significant associations were found with head injury, diabetes mellitus, and an AIMS score of 2 or greater in 2 body areas. Various classes of psychotropic agents seemed to have little influence on the MMSE or the development of dyskinesia and parkinsonism. Increasing age and a lower score on the MMSE seem to be particularly helpful in gauging the risk for parkinsonian and dyskinetic movements.

[Parkinsonism secondary to chronic subdural hematoma. A case report]

We described a case of secondary parkinsonism due to chronic subdural hematoma (CSH). An 83-year-old man developed memory impairment and gait disturbance gradually since one year ago, and these symptoms subacutely deteriorated after he fell down and hit his head. On admission he had moderate cognitive impairment, gait disturbance (wide-based, small steps and initial freezing), postual instability, akinesia and right-sided rigidity. He did not have resting tremor. A CT scan showed a right-sided CSH with marked compression on the left hemisphere, and remarkable decrease of the blood flow in the left cerebral hemisphere was revealed by single photon emission computed tomography. His neurological condition improved gradually through the decrease of the CSH, which suggested the diagnosis of secondary parkinsonism due to CSH. We thought that the CSH in the right hemisphere caused right-sided parkinsonism through mechanical compression to the left hemisphere, which was shown in the SPECT image, in this case. Elderly people suffering from subacute progressive parkinsonism, should undergo CT studies be to differentiate the parkinsonism secondary to CSH.

Psychogenic parkinsonism: a combination of clinical, electrophysiological, and [(123)I]-FP-CIT SPECT scan explorations improves diagnostic accuracy

We evaluated the concordance between independent clinical, electrophysiological, and [(123)I]-FP-CIT SPECT scan explorations as a staged procedure for an accurate diagnosis in 9 patients referred with a diagnosis of suspected psychogenic parkinsonism. Three patients were reclassified as pure psychogenic parkinsonism (PP), 6 with a form of combined psychogenic parkinsonism and Parkinson's disease (PP + PD), and none with pure Parkinson's disease (PD). Electrophysiological recordings showed the characteristics of psychogenic tremor in 5 of 7 patients with tremor. In two of these 5, PD tremor was also recorded. SPECT scan results were abnormal in five of 9 patients. In one case of clinically suspected PP + PD, SPECT scan results were normal. Long-term follow-up supported the final diagnosis of PP (initial clinical misdiagnosis). Electrophysiology contributes to the clinical diagnosis of psychogenic tremor and may help confirm associated organic PD tremor. [(123)I]-FP-CIT SPECT is a robust test to ascertain dopaminergic denervation and increase the confidence of the clinical and electrophysiological diagnosis of associated PD. A combination of clinical, electrophysiological, and [(123)I]-FP-CIT SPECT scan explorations improves diagnostic accuracy in order to distinguish PP from PP + PD.

Developmental exposure to the pesticide dieldrin alters the dopamine system and increases neurotoxicity in an animal model of Parkinson's disease

Exposure to pesticides has been suggested to increase the risk of Parkinson's disease (PD), but the mechanisms responsible for this association are not clear. Here, we report that perinatal exposure of mice during gestation and lactation to low levels of dieldrin (0.3, 1, or 3 mg/kg every 3 days) alters dopaminergic neurochemistry in their offspring and exacerbates MPTP toxicity. At 12 wk of age, protein and mRNA levels of the dopamine transporter (DAT) and vesicular monoamine transporter 2 (VMAT2) were increased by perinatal dieldrin exposure in a dose-related manner. We then administered MPTP (2 x 10 mg/kg s.c) at 12 wk of age and observed a greater reduction of striatal dopamine in dieldrin-exposed offspring, which was associated with a greater DAT:VMAT2 ratio. Additionally, dieldrin exposure during development potentiated the increase in GFAP and alpha-synuclein levels induced by MPTP, indicating increased neurotoxicity. In all cases there were greater effects observed in the male offspring than the female, similar to that observed in human cases of PD. These data suggest that developmental exposure to dieldrin leads to persistent alterations of the developing dopaminergic system and that these alterations induce a "silent" state of dopamine dysfunction, thereby rendering dopamine neurons more vulnerable later in life.

Secondary parkinsonism in childhood: A rare complication after radiotherapy

Secondary parkinsonism is uncommon in children and exceedingly rare after cranial radiotherapy. This report describes a 14-year-old female who presented with growth retardation as a result of a craniopharyngioma, which was partially resected. A secondary hydrocephalus responded well to shunting. She gradually developed a severe hypokinetic-rigid syndrome 6 months after radiotherapy (54 Gray in 30 daily fractions of 1.8 Gray). In addition, her vigilance decreased. Magnetic resonance imaging revealed increased signal intensity on T2-weighted images in the globus pallidus bilaterally. Nuclear scans indicated only a marginal striatal dopaminergic deficit and revealed decreased metabolism in the thalamus bilaterally. Treatment with dopamine agonists resulted in minor improvement in motor function. Magnetic resonance imaging investigations 3 months later disclosed a decrease of signal intensity changes of the globus pallidus. Gradually, bradykinesia diminished slightly and vigilance increased little. In conclusion, secondary and partially reversible parkinsonism can occur in children after radiotherapy. We suggest that focal encephalopathy resulting from postradiation edema secondary to microangiopathy led to dysfunction of the globus pallidus and thalamus.

Cerebral hemosiderosis as a causative factor of vascular parkinsonism

Secondary parkinsonism has comprised about 20 to 40 percent of all parkinsonism patients in movement disorders clinic. Most of them are induced by certain medications. About 5 to 10 percent of these patients are caused by sudden vascular events, who suffer from their parkinsonism abruptly, and usually of aged people with quite apparent stroke risk factors. Hemosiderosis was only occasionally reported as a causative factor in patients with parkinsonism, who presented with an insidious onset parkinsonism and a progressive supranuclear palsy-like clinical picture. We encountered two patients with stroke-related parkinsonism, whose high resolution MRI image showed apparent cortical or intraparenchymal hemosiderosis, although Binswanger type white matter change was also noted. Intracerebral hemosiderosis that manifests clinically as vascular parkinsonism might be much more frequent than we thought.

Carbon monoxide brain toxicity: clinical, magnetic resonance imaging, magnetic resonance spectroscopy, and neuropsychological effects in 9 people

Carbon monoxide (CO) exposure is a common cause of toxic brain damage, whereby effects range from transient neurological dysfunction to coma and death. A spectrum of severity of magnetic resonance imaging (MRI) findings after CO brain toxicity, including globus pallidus and white matter lesions, is well documented. Reports of MR spectroscopy (MRS) findings re main sparse. This article reports 9 people exposed to CO because of an apartment house's faulty gas heater. Four, with transient loss of consciousness after chronic moderate level CO exposure, suffered intellectual impairment without MRI abnormalities. The MRS of 1 individual demonstrated decreased n-acetyl aspartase in the basal ganglia, bilaterally. Of 5 exposed to high levels for about 12 hours, 1 died prior to clinical and/or MRI evaluation. One who suffered coma recovered but was lost to evaluation. Three, who were unconscious for hours to days, exhibited T2 MRI white matter signal abnormalities. MRS showed decreased basal ganglia n-acetyl aspartase in 2. One of these suffers a Parkinsonian syndrome. All 3 are intellectually impaired. This study demonstrates that although MRI and MRS are useful markers of CO-induced brain damage, they are not always sensitive to resultant intellectual dysfunction.

[A case of interval form of carbon monoxide poisoning with a remarkable recovery]

A 69-year-old woman was admitted to our hospital due to an interval form of carbon monoxide (CO) poisoning one month after acute CO poisoning. On admission, she had disorientation, memory disturbance, apathy, masked face, muscle rigidity, bradykinesia and parkisonian gait. An MRI (FLAIR image) revealed high signal intensity lesions in the bilateral globus pallidus and the white matter of the frontal lobe. Hyperbaric oxygen (HBO) therapy at 2 atmospheres for 60 min was given every day, in addition to citicoline, levodopa/DCI and selegiline hydrochloride. Cognitive disturbance and parkinsonism gradually decreased, and abnormal signals in the bilateral globus pallidus and the cerebral white matter were attenuated after the treatment. Neuropsychiatric abnormalities except for a slight gait disturbance disappeared one and a half month after starting the treatment. In addition to HBO therapy, administration of citicoline, lovodopa and selegiline may be useful in the case of the interval form of CO poisoning.

Postural changes after lesions of the substantia nigra pars reticulata in hemiparkinsonian monkeys

Current neurosurgical strategies target overactive brain regions including the subthalamic nucleus, globus pallidus and thalamus to control various symptoms of Parkinson's disease. Subthalamotomy improves akinesia and can induce postural deficits in both parkinsonian humans and animals, pallidotomy improves limb dyskinesia and more variably, distal bradykinesia whilst thalamotomy improves tremor. Because the SNr also becomes overactive in PD and there are few surgical studies in parkinsonian primates, we therefore evaluated the effects of lesioning the SNr in hemiparkinsonian marmosets to establish the effects on symptomatology. Nine monkeys received unilateral 6-hydroxydopamine (6-OHDA) lesions. Seven weeks later, four received kainic acid lesions of the SNr. Behavioural tests were performed prior to 6-OHDA surgery and then fortnightly for 14 weeks. Unilateral 6-OHDA lesions induced ipsilateral postural bias, ipsilateral rotation after amphetamine injection and bradykinesia. Whilst, SNr lesions significantly altered the direction of head position and amphetamine-induced rotation relative to 6-OHDA lesions, there was no improvement in 6-OHDA-induced reaching deficits or sensorimotor neglect. Unbiased quantitation of the nigral lesions showed on average 88% loss of dopaminergic neurons after 6-OHDA lesions and 77% loss of non-dopaminergic neurons after SNr lesions. Our results demonstrate that the SNr is important in body orientation changes in parkinsonism.

Parkinsonism following bilateral lesions of the globus pallidus: performance on a variety of motor tasks shows similarities with Parkinson's disease

OBJECTIVES

The authors report the results of detailed investigations into the motor function of a patient who, after a heavy drinking binge and subsequent unconsciousness, respiratory acidosis, and initial recovery, developed parkinsonism characterised by hypophonic speech and palilalia, "fast micrographia", impaired postural reflexes, and brady/akinesia in proximal (but not distal) alternating upper limb movements.

METHODS

In addition to brain magnetic resonance imaging (MRI), different aspects of motor function were investigated using reaction time (RT) tasks, pegboard and finger tapping tasks, flex and squeeze tasks, movement related cortical potentials (MRCPs), and contingent negative variation (CNV). Cognitive function was also assessed. The results were compared to those previously reported in patients with Parkinson's disease (PD).

RESULTS

Brain MRI showed isolated and bilateral globus pallidus (GP) lesions covering mainly the external parts (GPe). These lesions were most probably secondary to respiratory acidosis, as other investigations failed to reveal an alternative cause. The results of the RT tasks showed that the patient had difficulties in preparing and maintaining preparation for a forthcoming movement. MRCP and CNV studies were in line with this, as the early component of the MRCP and CNV were absent prior to movement. The patient's performance on pegboard and finger tapping, and flex and squeeze tasks was normal when performed with one hand, but clearly deteriorated when using both hands simultaneously or sequentially.

CONCLUSIONS

In general, the present results were similar to those reported previously in patients with PD. This provides further indirect evidence that the output of globus pallidus is of major importance in abnormal motor function in PD. The possible similarities of the functional status of GP in PD and our case are discussed.

[Iatrogenic neurological disorders in old people: a review]

Aged people are frequently the victims of iatrogenic diseases, especially adverse effects of drugs since they are affected by many age-related diseases and are given many drugs. Geriatric medicine in Japan has a bitter history of having produced many victims by adverse effects of cerebral vasodilators and cerebral stimulants; they included parkinsonism and depression induced by flunarizine and cinnarizine, and Reye-like encephalopathy induced by calcium hopantenate. Parkinsonism induced by sulpiride, tiapride, metoclopramide or atypical anti-psychotics, dyskinesia induced by anti-parkinsonian drugs or anti-psychotics, and psychotic symptoms induced by anti-parkinsonian drugs, anti-cholinergic drugs, anti-depressants or histamine H2 antagonists are still very common. Wernicke encephalopathy caused by intravenous glucose infusion without thiamine, central pontine myelinolysis by too rapid correction of hyponatremia are important though infrequent. Iatrogenic Creutzfeldt-Jakob disease by dura grafts is a warning against the easy use of medical materials produced with human organs or blood. Iatrogenic diseases are preventable, and geriatricians have to pay attention to the information on adverse effects of drugs and medical materials and carefully observe the early signs of iatrogenic diseases.

Dexamethasone protects against dopaminergic neurons damage in a mouse model of Parkinson's disease

The pathological process of neurodegeneration, which is observed in Alzheimer's (AD) and Parkinson's (PD) diseases and that follows any insult to the central nervous system, is accompanied by an inflammatory reaction, which is believed to contribute to the pathogenesis of the diseases. In accordance to this, the anti-inflammatory agents are suggested to be effective in slowing or inhibiting the degenerative process. In this study, we investigated the influence of dexamethasone (DXM) on the nigrostriatal dopaminergic neurons damage following administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropiridine (MPTP). Mice C57BL received pre-treatment of the various doses of dexamethasone followed by MPTP administration (40 mg/kg). We found that dexamethasone 1 mg/kg diminished a dopamine content depletion in striatum by about 20%, when the doses of 0.1 mg/kg was ineffective and 10 mg/kg even aggravate the dopamine content decrease. In the second step of the experiment, we chose the effective doses, 1 mg/kg, and started the treatment before and 24 h after MPTP administration. We observed the same protection in both situations: less dopamine depletion and less decrease in the number of dopaminergic cells in the substantia nigra (SN). Dexamethasone also similarly decreased the inflammatory reaction (glial activation, lymphocytic infiltration) in the injured areas. Our study showed that dexamethasone may exert a neuroprotective effect towards neurons injured by MPTP, but only when used in a proper dose. The mechanism of dexamethasone protective properties may be an inhibition of inflammatory process; however, direct interactions with neurons are also possible.

Dysregulation of gene expression in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned mouse substantia nigra

Parkinson's disease pathogenesis proceeds through several phases, culminating in the loss of dopaminergic neurons of the substantia nigra (SN). Although the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of oxidative SN injury is frequently used to study degeneration of dopaminergic neurons in mice and non-human primates, an understanding of the temporal sequence of molecular events from inhibition of mitochondrial complex 1 to neuronal cell death is limited. Here, microarray analysis and integrative data mining were used to uncover pathways implicated in the progression of changes in dopaminergic neurons after MPTP administration. This approach enabled the identification of small, yet consistently significant, changes in gene expression within the SN of MPTP-treated animals. Such an analysis disclosed dysregulation of genes in three main areas related to neuronal function: cytoskeletal stability and maintenance, synaptic integrity, and cell cycle and apoptosis. The discovery and validation of these alterations provide molecular evidence for an evolving cascade of injury, dysfunction, and cell death.

[Diseases other than Parkinson's disease presenting with parkinsonism]

Among the diseases causing parkinsonism, drug-induced parkinsonism is important because physicians often use anti-dopaminergic drugs such as benzamides for gastrointestinal disorders. In 28 patients with drug-induced parkinsonism, 13 (47%) showed persistent parkinsonism even 6 months after the cessation of the causative drugs. This means anti-dopaminergic drugs may bring subclinical parkinsonism to the clinical level especially in the elderly. Progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and multiple system atrophy including striatonigral degeneration were recognized in 2003 as specific diseases by the National Health Insurance of Japan. The diagnostic criteria of PSP (the modification of NINDS-SPSP criteria) made by the study group of the Ministry of Health, Welfare and Labour (MHWL) of Japan has demonstrated that their sensitivity was 83% and specificity 97% in "probable PSP". Patients with CBD were surveyed among the main neurologic institutions in Japan using the provisional diagnostic criteria There were 151 patients with "probable CBD" and 13 with "definite CBD". Based on these data, the number of patients with PSP and CBD in 2001 was estimated as 6,400 (5.03 per 100,000) and 2,500 (1.93 per 100,000), respectively, in Japan. Neuroprotective drugs hold hope for the treatment of neurodegenerative diseases. Although many agents were reported to be neuroprotective for Parkinson's disease from in vitro studies, pramipexole, a dopamine agonist, is the only one with good clinical evidence based on neuroimaging. Other dopamine agonists as well as various nerve trophic factors may also have the same effects, though further confirmatory studies are necessary.

123I-FP-CIT SPECT imaging of dopamine transporters in patients with cerebrovascular disease and clinical diagnosis of vascular parkinsonism

The purpose of our study was to prospectively evaluate the striatal uptake of 123I-labeled N-(3-fluoropropyl)-2beta-carbomethoxy-3beta-(4-iodophenyl)nortropane (FP-CIT) and the response to l-dopa therapy in patients with cerebrovascular disease (CVD) who develop clinical symptoms of vascular parkinsonism (VP).

METHODS

Twenty consecutive patients who developed VP in the course of CVD were prospectively enrolled in the study. All patients had CT evidence of CVD (17 patients had lacunar infarcts, 3 patients had territorial strokes). The clinical stage of the patients was assessed using the Hoehn and Yahr scale, and the severity of the symptoms was measured using the Unified Parkinson's Disease Rating Scale score. Ten age-matched subjects were used as controls. SPECT was performed 180 min after injection of 185 MBq 123I-FP-CIT using a dual-head gamma-camera. The ratio of the mean specific-to-nonspecific striatal binding for the entire striatum, caudate, and putamen was calculated in all patients and compared with that of controls. Putamen-to-caudate binding ratios were compared as well. The response to therapy was compared between patients with normal and abnormal 123I-FP-CIT binding.

RESULTS

No correlation was found between any of the clinical variables and response to therapy in patients with VP. Nine patients had normal striatal 123I-FP-CIT binding with no significant differences in striatal or subregional binding ratios compared with those of the controls. In contrast, 11 patients had significantly diminished striatal binding compared with that of controls (P < 0.001). Subanalyses showed significantly decreased binding in the caudate (P < 0.04 and P < 0.01 for the right and left caudate, respectively), diminished binding in the putamen (P < 0.04 and P < 0.01 for the right and left putamen, respectively), and a decreased putamen-to-caudate ratio on the right side (P < 0.001). The latter ratio was not significant on the left. Two of the 3 patients with territorial strokes had significantly diminished striatal 123I-FP-CIT binding in the hemisphere contralateral to the CT lesion. All 9 patients with normal scan findings had a poor response to L-dopa. Six of 11 patients with abnormal studies had no response to L-dopa, whereas 5 patients had a good response (P < 0.03).

CONCLUSION

The diagnosis of VP cannot be accurately confirmed on the basis of clinical features alone because CVD may alter the typical presentation of PD. Functional imaging with 123I-FP-CIT is highly recommended in patients with CVD who develop symptoms of VP to confirm or exclude the existence of nigrostriatal dopaminergic degeneration. Identifying a subset of patients with reduced 123I-FP-CIT binding in the striatum is important for better treatment selection.

Vascular parkinsonism

PURPOSE OF REVIEW

Vascular parkinsonism is a highly controversial concept since its first description by Critchley in 1929. There is no doubt that cerebrovascular disease can cause elements of parkinsonism. However, the extent of the spectrum of vascular parkinsonism remains quite imprecise. Here we review recent epidemiological, clinical, electrophysiological, morphological and functional brain imaging and pathological studies on 'vascular parkinsonism'.

RECENT FINDINGS

Epidemiological studies have demonstrated that vascular parkinsonism represents 3-5% of all cases of parkinsonism. The more specific clinical features are a history of stroke, lower body parkinsonism and poor levodopa response. Vascular risk factors are dominated by arterial hypertension, whereas others have been less evaluated. Vascular lesions within or outside the basal ganglia, unique and multiple, lacunae or territorial infarcts can be demonstrated by magnetic resonance imaging. Functional imaging of the dopaminergic pathway helps to differentiate vascular parkinsonism from idiopathic Parkinson's disease. However, none of these clinical or imaging criteria taken alone are specific for the diagnosis. A combination of convergent clinical and imaging clues are therefore necessary to improve the accuracy of the diagnosis, which is only certain when the pathology excludes underlying idiopathic Parkinson's disease.

SUMMARY

At present it remains unexplained why some patients develop vascular parkinsonism and others do not with the same apparent vascular lesion load. This will need further research along with the need to develop criteria to improve the accuracy of diagnosis of vascular parkinsonism. Vascular parkinsonism is also a research field on the relationships between vascular brain lesions and neurodegenerative disorders.