Non-traumatic Rectus Sheath Hematoma During Direct Oral Anticoagulation.

We report a case of anticoagulation therapy complicated by a non-traumatic rectus sheath hematoma (RSH). RSH is a relatively rare occurrence caused by bleeding into the rectus sheath following the rupture of the superior and inferior epigastric vessels combined with a primary tear of the rectus muscle fibers. Herein, we report a rare presentation of RSH in a 73-year-old man taking the direct oral anticoagulant (DOAC) apixaban orally. The patient presented with sudden right abdominal pain after a severe cough, which worsened with cough and movement. The Fothergill and Carnett signs were positive. The platelet count, renal function test, and the prothrombin time/international normalized ratio were within the normal range. The activated partial thromboplastin time was 40.0 s, slightly longer than normal. Computed tomography (CT) of the abdomen and pelvis showed RSH, and DOAC therapy was temporarily discontinued. Subsequently, RSH resolution was confirmed via CT four weeks after the onset. DOACs are safer and more efficacious than warfarin for patients with non-valvular atrial fibrillation. However, RSH is a potential complication of anticoagulant therapy. This case report demonstrates that RSH should be considered in the differential diagnosis of sudden-onset abdominal pain and mass in patients on DOACs.

High-risk patent foramen ovale and elderly in cryptogenic stroke.

BACKGROUND: High-risk patent foramen ovale (PFO) could be pathological in cryptogenic stroke (CS), but its clinical characteristics have not been fully studied, especially in elderly patients. METHODS: Patients with CS were enrolled in the CHALLENGE ESUS/CS registry, a multicenter registry of CS patients undergoing transesophageal echocardiography. Clinical characteristics were compared among three groups: high-risk PFO group, large shunt PFO (≥25 microbubbles) or PFO with atrial septal aneurysm (ASA); right-to-left shunt (RLS) group, RLS including PFO with <25 microbubbles or without ASA; and no-RLS group. RESULTS: In total, 654 patients were analyzed: 91, 221, and 342 in the high-risk PFO, RLS, and no-RLS groups, respectively. In multinomial logistic regression analysis, the male sex (odds ratio [OR] 1.825 [1.067-3.122]) was independently associated with high-risk PFO, but hypertension (OR, 0.562 [0.327-0.967]), multiple infarctions (OR, 0.601 [0.435-0.830]), and other cardioaortic embologenic risks (OR, 0.514 [0.294-0.897]) were inversely associated with high-risk PFO compared with non-RLS. In 517 patients aged ≥60 years, multiple infarctions (OR, 0.549 [0.382-0.788]) and other cardioaortic embologenic risks (OR, 0.523 [0.286-0.959]) were inversely associated with high-risk PFO. CONCLUSIONS: High-risk PFO had specific clinical characteristics and possible mechanistic associations, and this trend was consistent among CS patients aged ≥60 years. CLINICAL TRIAL REGISTRATION INFORMATION: http://www.umin.ac.jp/ctr/ (UMIN000032957).

Characteristics of sagittal spinopelvic alignment in patients with Parkinson's disease presenting with dropped head syndrome: a case series study.

BACKGROUND: Dropped head syndrome (DHS) is a rare specific abnormal posture known to develop in Parkinson's disease (PD). This case series study aimed to characterize DHS by analyzing the characteristics of sagittal spinopelvic alignment in patients with PD/DHS. METHODS: The study included eight patients with PD/DHS (men = 3, women = 5; mean age, 68.1 ± 6.4 years). Sagittal spinopelvic alignment was evaluated using 10 parameters on whole-spine lateral radiographs. RESULTS: The time from the onset of PD to that of DHS varied among the patients from 0 to 15.3 years. In three patients, DHS appeared before the diagnosis of PD. The severity of motor symptoms at DHS onset varied from modified Hoehn and Yahr stage 1 to 4 among the patients. Although the spinopelvic parameters differed among PD/DHS individuals, all patients exhibited cervical kyphosis (cervical lordosis < 0˚). In patients with a larger T1 slope and greater thoracic kyphosis, anterocollis tended to be more severe. According to the assessment of the sagittal vertical axis (SVA), half of the patients showed a positive SVA (SVA ≥ 0 mm), whereas the other half showed a negative SVA (SVA < 0 mm). CONCLUSION: DHS appeared regardless of the duration or severity of PD. Although all patients with PD/DHS exhibited cervical kyphosis, the C7 plumb line was shifted anteriorly in half of the patients and posteriorly in the other half.

Effect of Serum Perampanel Concentration on Sporadic Amyotrophic Lateral Sclerosis Progression.

BACKGROUND AND PURPOSE: To clarify the effect of perampanel (PER) on sporadic amyotrophic lateral sclerosis (sALS) progression, the relationship between the changes in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) scores and serum PER concentrations was investigated. METHODS: 12 patients with sALS from our hospital who agreed to participate and completed the PER for sALS randomized phase 2 study were included. After completing the study, we retrospectively obtained serum PER concentration data from the patients. Based on their mean PER concentrations, we divided the patients who had been taking PER into two groups: four patients with a mean PER concentration of ≥400 ng/mL were assigned to the H group, and three with a mean PER concentration of <400 ng/mL were assigned to the L group. The control group consisted of five patients who had been taking a placebo. We obtained the ALSFRS-R scores of each patient at 36 and 48 weeks after randomization. The differences in ALSFRS-R scores at baseline (0 weeks) and each subsequent week were used in the analysis. RESULTS: At 48 weeks, there were no differences in the degree of deterioration of the bulbar, upper and lower limb, and respiratory ALSFRS-R subscores and total ALSFRS-R score. However, at 36 weeks, the bulbar subscore was significantly lower in the H group than in the control group (p=0.032). CONCLUSIONS: Because high PER concentrations may exacerbate bulbar symptoms in patients with sALS, serum PER measurements may be beneficial when patients with sALS are taking PER.

Pathological features of glial cells and motor neurons in the anterior horn of the spinal cord in sporadic ALS using ADAR2 conditional knockout mice.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the selective degeneration of motor neurons (MNs). In the MNs of patients with ALS, adenosine deaminase acting on RNA 2 (ADAR2)-mediated RNA editing of GluA2 mRNA at the Q/R site is profoundly deficient. In genetically modified mice (ADAR2flox/flox/VAChT-Cre.Fast; AR2), the selective knockout of ADAR2 in cholinergic neurons induced progressive loss of lower MNs. MNs exhibiting an age-related increase in abnormal TDP-43 localization and reduced ADAR2 immunoreactivity are localized in the lateral areas of the anterior horns (AHs) in aged wild-type mice. However, the patterns in the AHs of AR2 mice remain unknown. In this study, we investigated whether similar degeneration is observed in AR2 mice. We compared the number of astrocytes and MNs in the lateral and medial AHs of the lumbar spinal cord of 12-month-old AR2 mice with age-matched wild-type mice. The number of MNs significantly decreased in both the lateral and medial areas in AR2 mice AHs, particularly in the former. The number of reactive astrocytes increased significantly in the lateral areas of the AHs of AR2 mice. In conclusion, stronger activation of astrocytes with reduction of MNs in the ADAR2 deficiency-related lateral area increases in AR2 mice AHs. Fast fatigable MNs are expected to be present in the lateral area of the AHs. We found that MN death is more common in the lateral area of AHs associated with FF MNs due to differences in vulnerability to MN under ADAR2 deficiency.

High frequency of HTRA1 AND ABCC6 mutations in Japanese patients with adult-onset cerebral small vessel disease.

BACKGROUND: This study aimed to clarify the frequency and clinical features of monogenic cerebral small vessel disease (mgCSVD) among patients with adult-onset severe CSVD in Japan. METHODS: This study included patients with adult-onset severe CSVD with an age of onset ≤55 years (group 1) or >55 years and with a positive family history (group 2). After conducting conventional genetic tests for NOTCH3 and HTRA1, whole-exome sequencing was performed on undiagnosed patients. Patients were divided into two groups according to the results of the genetic tests: monogenic and undetermined. The clinical and imaging features were compared between the two groups. RESULTS: Group 1 and group 2 included 75 and 31 patients, respectively. In total, 30 patients had NOTCH3 mutations, 11 patients had HTRA1 mutations, 6 patients had ABCC6 mutations, 1 patient had a TREX1 mutation, 1 patient had a COL4A1 mutation and 1 patient had a COL4A2 mutation. The total frequency of mutations in NOTCH3, HTRA1 and ABCC6 was 94.0% in patients with mgCSVD. In group 1, the frequency of a family history of first relatives, hypertension and multiple lacunar infarctions (LIs) differed significantly between the two groups (monogenic vs undetermined; family history of first relatives, 61.0% vs 25.0%, p=0.0015; hypertension, 34.1% vs 63.9%, p=0.0092; multiple LIs, 87.8% vs 63.9%, p=0.0134). CONCLUSIONS: More than 90% of mgCSVDs were diagnosed by screening for NOTCH3, HTRA1 and ABCC6. The target sequences for these three genes may efficiently diagnose mgCSVD in Japanese patients.

[Cytomegalovirus associated myelitis in a non-immunocompromised adult due to initial cytomegalovirus infection].

The patient was a 30-year-old man who developed muscle weakness in both lower extremities, sensory deficits below the fourth thoracic spinal cord level, and bladder rectal dysfunction owing to cytomegalovirus (CMV) associated myelitis. His blood tests showed mononucleosis, hepatic dysfunction, and the presence of serum CMV-IgM antibodies, and T2-weighted imaging on MRI displayed a continuous high signal on the ventral side of the spinal cord. Although his medical history and laboratory tests did not indicate that he was immunocompromised, we speculated he had CMV-associated myelitis. As the first infection with CMV in a non-immunocompromised adult can result in mononucleosis, we considered that this patient developed myelitis after mononucleosis caused by CMV infection for the first time. CMV-associated myelitis in non-immunocompromised individuals is rare. In general, CMV infections are common in immunosuppressed individuals. However, in Japan, adults with CMV antibodies have recently been decreasing, and hence CMV infections in non-immunocompromised adults are expected to increase in the future.

Prolyl Isomerase Pin1 Expression in the Spinal Motor Neurons of Patients With Sporadic Amyotrophic Lateral Sclerosis.

BACKGROUND AND PURPOSE: Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease. Selective deficiency of edited adenosine deaminase acting on RNA 2 (ADAR2), a key molecule in the acquisition of Ca2+ resistance in motor neurons, has been reported in sporadic ALS (sALS) spinal motor neurons. Since ADAR2 activity is positively regulated by prolyl isomerase Protein never in mitosis gene A interacting-1 (Pin1), a known phosphorylation-dependent peptidyl-prolyl cis/trans isomerase, we investigated Pin1 expression in spinal motor neurons in sALS. METHODS: Specimens of the spinal cord were obtained from the lumbar region in eight sALS patients and age-matched five controls after postmortem examinations. The specimens were double stained with anti-Pin1 and anti-TAR DNA-binding protein of 43 kDa (TDP-43) antibodies, and examined under a fluorescence microscope. RESULTS: This study analyzed 254 and 422 spinal motor neurons from 8 sALS patients and 5 control subjects, respectively. The frequency of motor neurons with high cytoplasmic Pin1 expression from the spinal cord did not differ significantly between sALS specimens without cytoplasmic TDP-43 inclusions and control specimens. However, in sALS specimens, neurons for which the Pin1 immunoluminescence intensity in the cytoplasm was at least twice that in the background were more common in specimens with cytoplasmic TDP-43 inclusions (p<0.05 in χ² test). CONCLUSIONS: In sALS, neurons with higher expression levels of Pin1 levels had more TDP-43 inclusions. Despite the feedback mechanism between Pin1 and ADAR2 being unclear, since Pin1 positively regulates ADAR2, our results suggest that higher Pin1 expression levels in motor neurons with TDP-43 pathology from sALS patients represent a compensatory mechanism.

Clinical Features of Parkinson's Disease in Patients with Early-Onset Freezing of Gait.

Background: Freezing of gait (FOG) is an important symptom that can impair activities of daily living in patients with Parkinson's disease (PD). However, its pathogenic mechanism is largely unknown. The aim of the present study was to elucidate the clinical characteristics of newly diagnosed and levodopa-naïve patients with PD who present with FOG. Methods: A total of 53 patients with untreated PD (29 men and 24 women) within 2 years of disease onset were included in the study. Using item 3 of the Freezing of Gait Questionnaire (FOG-Q), patients were classified as "freezers" and "nonfreezers" and compared for cognitive function, depressive symptoms, apathy, olfactory function, motor severity, gait parameters, and daily physical activity. We also assessed the relationship between FOG severity (total score of items 3-6 on the FOG-Q) and various clinical parameters. Results: The FOG was reported by 8 (15%) patients with PD. The Apathy Scale score (p=0.018), Modified Hoehn and Yahr stage (p < 0.001), Unified Parkinson's Disease Rating Scale part III score (p < 0.001), and postural instability and gait disorder score (p < 0.001) were significantly higher, and the mean gait acceleration amplitude (p=0.006) was significantly lower in freezers compared to that in nonfreezers. However, there was no significant correlation between FOG severity and these clinical parameters. There was also no significant difference in cognitive function, depressive symptoms, and olfactory function between the two groups. Daily physical activity was significantly lower in freezers than that in nonfreezers. Conclusions: Since FOG develops soon after PD onset, the study findings suggest that the FOG might be associated with the severity of apathy, motor symptoms, and in particular, gait disturbance.

[Usefulness of an anti-mouse cerebellar tissue-derived antigen antibody test in predicting immunotherapy efficacy in patients with idiopathic cerebellar ataxia].

BACKGROUND: Autoimmune cerebellar ataxia (AICA) is a general term for diseases in which the cerebellum is damaged by an autoimmune mechanism. For the diagnosis of the AICA, anti-thyroid antibodies (anti-thyroid peroxidase antibody and anti-thyroglobulin antibody), anti-glutamic acid decarboxylase (GAD) antibodies, and anti-gliadin antibodies are measured. Immunotherapy is known to be effective for AICA, but some patients with effective immunotherapy lack autoantibodies associated with cerebellar ataxia. The purpose of this study was to clarify whether the effectiveness of immunotherapy in patients with suspected AICA could be predicted by anti-mouse cerebellar tissue-derived antigen antibody tests. METHODS: This study was conducted on 25 patients with idiopathic cerebellar ataxia (excluding multiple system atrophy, hereditary spinocerebellar degeneration, cancer-bearing patients, and patients taking phenytoin) who received immunotherapy from 2005 to 2016 at Tokyo Medical University Hachioji Medical Center. The patients were suspected of having AICA because they were positive for cerebellar ataxia-related autoantibodies (anti-thyroid antibody, anti-GAD antibody, anti-gliadin antibody, or anti-transglutaminase 6 antibody) or other autoantibodies. Antibodies that bind to mouse cerebellar tissue-derived antigens were defined as "anti-mouse cerebellar tissue-derived antigen antibodies" in this study, and their IgG-class antibodies were comprehensively measured using a slot blot. RESULTS: Anti-mouse cerebellar tissue-derived antigen antibody test results were correlated with immunotherapy efficacy. Furthermore, the combination of anti-mouse cerebellar tissue-derived antigen and anti-GAD antibody tests could predict the effectiveness of immunotherapy with 83% sensitivity and 100% specificity, while the combination of the anti-mouse cerebellar tissue-derived antigen, anti-GAD, and anti-gliadin (IgA class) antibody tests could predict the effectiveness of immunotherapy with 94% sensitivity and 86% specificity. CONCLUSION: Anti-mouse cerebellar tissue-derived antigen antibody tests could help to provide useful information for immunotherapy administration to patients with idiopathic cerebellar ataxia suspected to be AICA.

Characteristics of sagittal spinopelvic alignment in patients with Parkinson's disease.

INTRODUCTION: The aim of this study was to characterize the associations between sagittal spinopelvic alignment and motor symptoms in patients with Parkinson's disease (PD). METHODS: The study included patients with idiopathic PD (aged <80 years and with abnormal posture). All patients underwent whole-spine lateral and coronal radiography. Sagittal spinopelvic alignment was evaluated using nine parameters. Motor symptoms were evaluated using the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III score-with bradykinesia and axial motor sub-scores. Multivariate analysis was used to analyze associations between motor symptoms and sagittal spinopelvic alignment in PD patients according to sex. RESULTS: The study subjects were 79 PD patients (39 men, 40 women; median age, 70 years). Clear sex-related differences were noted. In male patients, the MDS-UPDRS part III score correlated significantly with cervical sagittal vertical axis (SVA), and bradykinesia and axial motor scores correlated significantly with SVA, cervical SVA, and T1 slope. In female patients, the MDS-UPDRS part III score correlated significantly with thoracic kyphosis, bradykinesia score correlated significantly with cervical SVA and thoracic kyphosis, and the axial motor score correlated significantly with SVA, cervical SVA, T1 slope, sacral slope, and pelvic tilt. CONCLUSION: Our results showed clear correlations among various motor symptoms and sagittal global alignment in PD patients and that these correlations are different in female PD patients and their male counterparts.

Randomized phase 2 study of perampanel for sporadic amyotrophic lateral sclerosis.

OBJECTIVE: To evaluate the efficacy and safety of perampanel in patients with sporadic amyotrophic lateral sclerosis (SALS). METHODS: This randomized, double-blind, placebo-controlled, multicenter, phase 2 clinical study was conducted at 12 sites. Patients with probable or definite ALS as defined by revised El Escorial criteria were enrolled. Sixty-six patients were randomly assigned (1:1:1) to receive placebo, 4 mg perampanel, or 8 mg perampanel daily for 48 weeks. Adverse events (AEs) were recorded throughout the trial period. The primary efficacy outcome was the change in Amyotrophic Lateral Sclerosis Rating Scale-Revised (ALSFRS-R) score after 48 weeks of treatment. RESULTS: One patient withdrew before starting the treatment. Of 65 patients included, 18 of 22 patients randomized to placebo (82%), 14 of 22 patients randomized to 4 mg perampanel (64%), and 7 of 21 patients randomized to 8 mg perampanel (33%) completed the trial. There was a significant difference in the change of ALSFRS-R scores [- 8.4 (95% CI - 13.9 to - 2.9); p = 0.015] between the placebo and the perampanel 8 mg group, primarily due to worsening of the bulbar subscore in the perampanel 8 mg group. Serious AEs were more frequent in the perampanel 8 mg group than in the placebo group (p = 0.0483). CONCLUSIONS: Perampanel was associated with a significant decline in ALSFRS-R score and was linked to worsening of the bulbar subscore in the 8 mg group.

Distinction in Prevalence of Atherosclerotic Embolic Sources in Cryptogenic Stroke With Cancer Status.

Background Cerebrovascular diseases are common comorbidities in patients with cancer. Although active cancer causes ischemic stroke by multiple pathological conditions, including thromboembolism attributable to Trousseau syndrome, the relationship between stroke and inactive cancer is poorly known. The aim of this study was to elucidate the different underlying pathogeneses of cryptogenic stroke in active and inactive patients with cancer, with detailed investigation by transesophageal echocardiography. Methods and Results CHALLENGE ESUS/CS (Mechanisms of Embolic Stroke Clarified by Transesophageal Echocardiography for Embolic Stroke of Undetermined Source/Cryptogenic Stroke) registry is a multicenter registry including data of patients initially diagnosed as having cryptogenic stroke and undergoing transesophageal echocardiography. Patients were divided into active cancer, inactive cancer, and noncancer groups, and their clinical features were compared. Of the total 667 enrolled patients (age, 68.7±12.8 years; 455 men), 41 (6.1%) had active cancer, and 51 (7.5%) had a history of inactive cancer. On multinomial logistic regression analysis, infarctions in multiple vascular territories (odds ratio [OR], 2.73; 95% CI, 1.39-5.40) and CRP (C-reactive protein) (OR, 1.10; 95% CI, 1.01-1.19) were independently associated with active cancer, whereas age (OR, 1.05; 95% CI, 1.01-1.08), contralateral carotid stenosis from the index stroke lesion (OR, 4.05; 95% CI, 1.60-10.27), calcification of the aortic valve (OR, 2.10; 95% CI, 1.09-4.05), and complicated lesion of the aortic arch (OR, 2.13; 95% CI, 1.11-4.10) were significantly associated with inactive cancer. Conclusions Patients with cancer were not rare in cryptogenic stroke. Although patients with active cancer had more multiple infarctions, patients with inactive cancer had more atherosclerotic embolic sources potentially causing arteriogenic strokes. Registration URL: https://www.umin.ac.jp/ctr/; Unique identifier: UMIN000032957.

Persistent Hemichorea as a Preceding Symptom of Cerebral Infarction Due to Middle Cerebral Artery Stenosis.

We herein report an 84-year-old woman with right middle cerebral artery (MCA) stenosis who presented with persistent left hemichorea preceding cerebral infarction. She visited our hospital on day 9 after the hemichorea onset. Magnetic resonance imaging (MRI) showed no acute cerebral infarction. Magnetic resonance angiography revealed right MCA stenosis. Her hemichorea persisted for 19 days and subsequently disappeared. On day 21, she developed left hemiplegia. Repeat MRI revealed a cerebral infarction in the right putamen. MCA stenosis can present with persistent hemichorea, even in the absence of cerebral infarction. Persistent hemichorea with MCA stenosis may presage cerebral infarction.

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

INTRODUCTION: Although functional imaging is useful for the diagnosis and pathophysiological evaluation of Parkinson's disease (PD), little is known about the relationship between functional imaging findings and PD clinical features. The objective of this study was to determine the relationship between 123I-FP-CIT-SPECT findings and motor symptoms, in particular gait disturbance. METHODS: The study included 46 drug-naive patients with early-stage PD. The specific binding ratios (SBRs) in the striatum and its subregions, namely anterior/posterior putamen and caudate nucleus, were calculated in patients who underwent 123I-FP-CIT-SPECT. Motor symptoms were evaluated using the modified Hoehn and Yahr (HY) stage and the Unified Parkinson's Disease Rating Scale (UPDRS) part III. Gait disturbance was evaluated by the mean gait cycle duration and the mean gait acceleration amplitude measured with a wearable sensor. RESULTS: The mean SBRs of the striatum and anterior putamen were significantly associated with the modified HY stage and UPDRS part III score. The mean SBR of the caudate nucleus was significantly associated with the UPDRS part III score. The mean striatal SBR was also significantly associated with the mean gait cycle duration and mean gait acceleration amplitude. CONCLUSION: The mean striatal SBR, as determined by 123I-FP-CIT-SPECT, was significantly associated with motor severity and gait severity in drug-naive patients with PD.

[Posterior reversible encephalopathy syndrome during intravenous immunoglobulin therapy in Guillain-Barré syndrome].

A 63-year-old woman was diagnosed with Guillain-Barré syndrome (GBS), and intravenous immunoglobulin (IVIg) therapy was initiated. On the second day of IVIg therapy, she became less alert (JCS III-200) and had hyponatremia. Brain MRI showed vasogenic edema in bilateral occipital lobes, which disappeared afterwards. Her clinical course and MRI findings were consistent with those of posterior reversible encephalopathy syndrome (PRES). As a result of considering the timing of the onset of GBS and PRES and the degree of hyponatremia and hypertension in some documented patients, the cause of PRES onset in this case is considered to be IVIg therapy itself and IVIg therapy-induced hyponatremia.

Impact of the catechol-O-methyltransferase Val158Met polymorphism on the pharmacokinetics of L-dopa and its metabolite 3-O-methyldopa in combination with entacapone.

In the pharmacotherapy of patients with Parkinson's disease (PD), entacapone reduces the peripheral metabolism of L-dopa to 3-O-methyldopa (3-OMD), thereby prolonging the half-life (t1/2) of L-dopa and increasing the area under the concentration curve (AUC). The effect of entacapone on the pharmacokinetics of L-dopa differs between patients with high-activity (H/H) and low-activity (L/L) catechol-O-methyltransferase (COMT) Val158Met polymorphisms, but the effects are unclear in heterozygous (H/L) patients. 3-OMD has a detrimental effect and results in a poor response to L-dopa treatment in patients with PD; however, the influence of this polymorphism on the production of 3-OMD remains unknown. Therefore, the present study aimed to clarify the effect of the COMT Val158Met polymorphism on the concentrations of L-dopa and 3-OMD in the presence of entacapone. We performed an open-label, single-period, single-sequence crossover study at two sites in Japan. The study included 54 Japanese patients with PD, who underwent an acute L-dopa administration test with and without 100 mg entacapone on two different days. Entacapone increased L-dopa AUC0-infinity by 1.59 ± 0.26-fold in the H/H group, which was significantly higher than that in the H/L (1.41 ± 0.36-fold) and L/L (1.28 ± 0.21-fold) groups (p < 0.05). The concurrent administration of L-dopa with entacapone suppressed the increase in 3-OMD levels compared with L-dopa alone in all genotypes. Our results suggest that the COMT Val158Met polymorphism may be an informative biomarker for individualized dose adjustment of COMT inhibitors in the treatment of PD.