Drug-induced parkinsonism (DIP) is the second-most-common etiology of parkinsonism in the elderly after Parkinson's disease (PD). Many patients with DIP may be misdiagnosed with PD because the clinical features of these two conditions are indistinguishable. Moreover, neurological deficits in patients with DIP may be severe enough to affect daily activities and may persist for long periods of time after the cessation of drug taking. In addition to typical antipsychotics, DIP may be caused by gastrointestinal prokinetics, calcium channel blockers, atypical antipsychotics, and antiepileptic drugs. The clinical manifestations of DIP are classically described as bilateral and symmetric parkinsonism without tremor at rest. However, about half of DIP patients show asymmetrical parkinsonism and tremor at rest, making it difficult to differentiate DIP from PD. The pathophysiology of DIP is related to drug-induced changes in the basal ganglia motor circuit secondary to dopaminergic receptor blockade. Since these effects are limited to postsynaptic dopaminergic receptors, it is expected that presynaptic dopaminergic neurons in the striatum will be intact. Dopamine transporter (DAT) imaging is useful for diagnosing presynaptic parkinsonism. DAT uptake in the striatum is significantly decreased even in the early stage of PD, and this characteristic may help in differentiating PD from DIP. DIP may have a significant and longstanding effect on patients' daily lives, and so physicians should be cautious when prescribing dopaminergic receptor blockers and should monitor patients' neurological signs, especially for parkinsonism and other movement disorders.

Patients with CSF hypovolemia frequently have distinct MRI and radioisotope cisternographic abnormalities and often respond favorably to an epidural blood patch.

IMPORTANCE Large-scale genome-wide association studies in the European population have identified 90 risk variants associated with Parkinson disease (PD); however, there are limited studies in the largest population worldwide (ie, Asian).OBJECTIVES To identify novel genome-wide significant loci for PD in Asian individuals and to compare genetic risk between Asian and European cohorts.DESIGN SETTING, AND PARTICIPANTS Genome-wide association data generated from PD cases and controls in an Asian population (ie, Singapore/Malaysia, Hong Kong, Taiwan, mainland China, and South Korea) were collected from January 1, 2016, to December 31, 2018, as part of an ongoing study. Results were combined with inverse variance meta-analysis, and replication of top loci in European and Japanese samples was performed. Discovery samples of 31 575 individuals passing quality control of 35 994 recruited were used, with a greater than 90% participation rate. A replication cohort of 1 926 361 European-ancestry and 3509 Japanese samples was analyzed. Parkinson disease was diagnosed using UK Parkinson's Disease Society Brain Bank Criteria. MAIN OUTCOMES AND MEASURESGenotypes of common variants, association with disease status, and polygenic risk scores. RESULTS Of 31 575 samples identified, 6724 PD cases (mean [SD] age, 64.3 [10] years; age at onset, 58.8 [10.6] years; 3472 [53.2%] men) and 24 851 controls (age, 59.4 [11.4] years; 11 030 [45.0%] men) were analyzed in the discovery study. Eleven genome-wide significant loci were identified; 2 of these loci were novel (SV2C and WBSCR17) and 9 were previously found in Europeans. Replication in European-ancestry and Japanese samples showed robust association for SV2C (rs246814; odds ratio, 1.16; 95% CI, 1.11-1.21; P = 1.17 × 10 −10 in metaanalysis of discovery and replication samples) but showed potential genetic heterogeneity at WBSCR17 (rs9638616; I 2 =67.1%; P = 3.40 × 10 −3 for hetereogeneity). Polygenic risk score models including variants at these 11 loci were associated with a significant improvement in area under the curve over the model based on 78 European loci alone (63.1% vs 60.2%; P = 6. 81 × 10 −12 ).CONCLUSIONS AND RELEVANCE This study identified 2 apparently novel gene loci and found 9 previously identified European loci to be associated with PD in this large, meta-genome-wide association study in a worldwide population of Asian individuals and reports similarities and differences in genetic risk factors between Asian and European individuals in the risk for PD. These findings may lead to improved stratification of Asian patients and controls based on polygenic risk scores. Our findings have potential academic and clinical importance for risk stratification and precision medicine in Asia.

Parkinson disease (PD), progressive supranuclear palsy (PSP), and multiple-system atrophy (MSA) are known to affect dopaminergic neurons of the brain stem and striatum with different preferential involvement. Here we investigated differences in striatal subregional dopamine transporter loss in PD, PSP, and MSA and assessed the diagnostic value of 18 F-fluorinated-N-3-fluoropropyl-2-b-carboxymethoxy-3-b-(4-iodophenyl)nortropane ( 18 F-FP-CIT) PET in differentiating PSP and MSA from PD. Methods: Forty-nine patients with PD, 19 patients with PSP, 24 patients with MSA, and 21 healthy people (healthy controls) were examined with 18 F-FP-CIT PET. The PET images were spatially normalized and analyzed with 12 striatal subregional volume-of-interest (VOI) templates (bilateral ventral striatum [VS], anterior caudate [AC], posterior caudate, anterior putamen, posterior putamen [PP], and ventral putamen [VP]) and 1 occipital VOI template. The nondisplaceable binding potential (BP ND ) and intersubregional ratio (ISR; defined as the ratio of the BP ND of one striatal subregion to that of another striatal subregion) of subregional VOIs were calculated. Results: The BP ND of all VOIs in the PD, MSA, and PSP groups were significantly lower than those in the healthy controls (P , 0.05). The BP ND of AC and the AC/VS ISR in the PSP group were significantly lower than those in the PD group. The BP ND of VP was significantly lower, but the PP/VP ISR was significantly higher in the MSA group than in the PD group. At the cutoff value for the AC/VS ISR (,0.7), the sensitivity and specificity for differentiating PSP from PD were 94% and 92%, respectively. At the cutoff value for the PP/VP ISR (.0.65), the sensitivity and specificity for differentiating MSA from PD were 90% and 45%, respectively. The diagnostic accuracy of visual analysis was similar to that of quantitative analysis for differentiating PSP from PD but was significantly higher for differentiating MSA from PD. Conclusion: Compared with PD, PSP and MSA showed more prominent and earlier dopamine transporter loss in the AC and VP, respectively. These findings could be useful for suggesting PSP or MSA in parkinsonian cases without characteristic atypical features.

Post-stroke hemichorea is an uncommon involuntary hyperkinetic disorder involving unilateral body parts. The incidence and precise lesion location of post-stroke hemichorea remain unclear. The authors describe 27 consecutive patients with hemichorea after stroke. The incidence of post-stroke hemichorea was 0.54 % (27 out of 5,009 patients). The lesions were located in the caudate and putamen (n = 6), cortex (n = 6), thalamus and subthalamic area (n = 4), subthalamus (n = 4), putamen (n = 3), caudate (n = 2), and the globus pallidus (n = 2). Over the mean follow-up period of 22 months, the hemichorea disappeared in 56% of the patients, while it persisted in others. The rate of disappearance of hemichorea was significantly higher in patients with cortical strokes than in those with subthalamic lesions (P < 0.05). We conclude that hemichorea is a rare manifestation of stroke and most often produced by lenticular lesions followed by subthalamic and cortical lesions. The functional prognosis is better in patients with cortical lesions than those with subthalamic strokes.

Genetics has proven to be a powerful approach in neurodegenerative diseases research, resulting in the identification of numerous causal and risk variants. Previously, we introduced the NeuroX Illumina genotyping array, a fast and efficient genotyping platform designed for the investigation of genetic variation in neurodegenerative diseases. Here, we present its updated version, named NeuroChip. The NeuroChip is a low cost, custom-designed array containing a tagging variant backbone of about 306,670 variants complemented with a manually curated custom content comprised of 179,467 variants implicated in diverse neurological diseases, including Alzheimer's disease, Parkinson's disease, Lewy body dementia, amyotrophic lateral sclerosis, frontotemporal dementia, progressive supranuclear palsy, corticobasal degeneration and multiple system atrophy. The tagging backbone was chosen because of the low cost and good genome-wide resolution; the custom content can be combined with other backbones, like population or drug development arrays. Using the NeuroChip, we can accurately identify rare variants and impute over 5.3 million common SNPs from the latest release of the Haplotype Reference Consortium. In summary, we describe the design and usage of the NeuroChip array, and show its capability for detecting rare pathogenic variants in numerous neurodegenerative diseases. The NeuroChip has a more comprehensive and improved content, which makes it a reliable, high-throughput, cost-effective screening tool for genetic research and molecular diagnostics in neurodegenerative diseases.

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Objective: To analyze and update the clinical symptomatology, CT and MRI findings, angiographic features, and therapeutic outcomes of patients with dural arteriovenous fistulas (DAVFs). Background: Studies of DAVFs in a large number of patients have seldom appeared in neurology literature. Methods: The authors investigated 60 consecutive patients with DAVFs who were admitted between January 1991 and January 2001. The DAVFs were graded into five types according to the classification of Cognard et al. [Radiology 1995;194:671–680]. Presumable etiologies, clinical features, imaging findings and therapeutic outcomes were evaluated on the basis of the location and type of DAVFs. Results: Sinus thrombosis, previous trauma, craniotomy, cerebral infarction and acupuncture were detected as possible etiologic factors of DAVFs. The cavernous sinus (57%) was the most common location of DAVFs. Although the neurological symptoms were closely related to the location of the DAVFs, in some patients, there were also symptoms that did not reflect the location. Although the women outnumbered the men, the men presented with aggressive neurological manifestations more often (p < 0.05). Ten out of 12 patients (83%) with DAVFs involving locations other than the large sinuses presented with aggressive neurological manifestations. 70% of brain CTs and 81% of brain MRIs showed abnormal findings suggestive of DAVFs. Of 33 patients who underwent only endovascular embolization, 29 patients (88%) were cured or improved. Radiosurgery and surgical excision done in some patients provided fair results. Patients with DAVFs involving large sinuses showed a better therapeutic outcome than those in whom locations other than the large sinuses were involved, while patients without venous ectasia had more a favorable outcome than those with it (each, p < 0.01). Conclusions: DAVFs result from various etiologic factors, show diverse manifestations usually reflecting the location and can be treated successfully in most patients. Factors related to poor clinical outcome include male sex, the presence of venous ectasia and involved locations other than the large sinuses.