Publications by authors named "Ken Johkura"

Background: Sound stimulation can influence electrophysiological vestibular reflexes. However, the effects of sound stimulation on space perception remain unknown.

Objective: To know the effects of monaural sound stimulation on subjective visual vertical (SVV).

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Article Synopsis
  • This study investigated repeat expansion in patients with adult-onset cerebellar ataxia, focusing on the differences between Japanese and non-Japanese populations.
  • The researchers used nanopore sequencing to analyze samples from 460 Japanese patients and various control groups, finding that different repeat motifs (GCA in Japanese vs. GGA in non-Japanese) affect pathogenicity.
  • Ultimately, the study highlights how unique features of repeat expansion and genetic background contribute to the prevalence of the disease in different ethnic groups.
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Purpose: Tandem occlusion, in which the intracranial artery is obstructed along with proximal carotid occlusive or stenotic lesions, occurs in 10-15% of patients with large vessel occlusion. Our study introduces a novel technique for tandem occlusion treatment that involves the simultaneous coaxial deployment of a percutaneous transluminal angioplasty balloon and aspiration catheters with the delivery wire of a stent retriever. After percutaneous transluminal angioplasty of the carotid lesion with a thin balloon catheter, the aspiration catheter was advanced over the balloon to eliminate the ledge between the catheter tip and delivery wire.

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Platelet hyperactivity often occurs in patients with coronavirus disease 2019 (COVID-19). However, it remains unclear how long platelet hyperactivity lasts after the acute phase, owing to a lack of follow-up studies. To elucidate the course of platelet hyperactivity, we serially measured platelet activity in patients with COVID-19 up to 40 days after hospital admission using an easily assessable haematology analyser that semi-quantitates platelet clumps on a scattergram.

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This study aimed to test our hypothesis that the cerebellum plays an important role in the generation of the optical-geometric illusion known as the Poggendorff illusion, the mechanism of which has been explained by accumulated experience with natural scene geometry. A total of 79 participants, comprising 28 patients with isolated cerebellar stroke, 27 patients with isolated cerebral stroke and 24 healthy controls, performed Poggendorff illusion tasks and 2 different control tasks. We also investigated core brain regions underpinning changes in the experience of the illusion effect using multivariate lesion-symptom mapping.

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Objectives: A foreign body granuloma after an endovascular intervention is a rare complication. Some cases of foreign body granulomas, especially after coil embolization, have been reported. However, only four cases of foreign body granulomas after mechanical thrombectomy (MT) have previously been reported.

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Background: Carotid endarterectomy (CEA) and carotid artery stenting (CAS) are common treatments for ischemic stroke prevention in patients with carotid artery stenosis. However, the beneficial effects of CEA/CAS for cerebral hypoperfusion due to carotid artery stenosis have yet to be fully established. As dizziness is a common symptom in patients with carotid artery stenosis, we aimed to evaluate the effects of CEA/CAS on cerebral function in patients with carotid artery stenosis, using equilibrium function tests.

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Background And Purpose: Dizziness may persist even after the causative vestibular imbalance subsides. Although the precise mechanism of chronic dizziness is unknown, various cerebral activity changes associated with it have been reported. To understand its mechanism in the absence of the causative vestibular imbalance, we compared cerebral changes in chronic dizziness with and without persistent vestibular imbalance.

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[Vertigo and dizziness].

Rinsho Shinkeigaku

May 2021

Pathophysiology of vertigo/dizziness can be understood by eye deviation (nystagmus). In benign paroxysmal positional vertigo, eye deviation of causative semicircular canal stimulation is directly observed. In other peripheral vestibular disorders, eye deviation results from the sum of unilateral all semicircular canal disorders.

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Background And Purpose: The presence of hemispatial neglect adversely affects functional outcomes in stroke patients; consequently, it warrants early targeted rehabilitative intervention. Nevertheless, hemispatial neglect in the acute phase of stroke has often been underdiagnosed. In this study, we aimed to detect hemispatial neglect at the bedside in acute stroke patients by measuring eye movements using video-oculography (VOG).

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[Hypoglycemia].

No Shinkei Geka

March 2021

Hypoglycemia may lead to acute hemiplegia. The most common diffusion-weighted MRI finding in patients with hypoglycemic hemiplegia is a hyperintense internal capsule lesion, which mimics acute ischemic stroke. In addition to the internal capsule lesion, various MRI findings have been reported in patients with hypoglycemia(including hyperintense lesions in the cerebral cortex, basal ganglia, subcortical white matter, and splenium of the corpus callosum).

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Objective: Carotid artery stenosis and cerebral aneurism may have different platelet functions and antiplatelet responses because these diseases have different etiologies. In this study, we compared the antiplatelet loading effects prior to endovascular treatment between carotid artery stenosis and unruptured cerebral aneurysm (UCA) patients.

Methods: Nine patients with asymptomatic carotid artery stenosis (ACS), 14 with symptomatic carotid artery stenosis (SCS), and 20 with unruptured cerebral aneurysms were enrolled in this study.

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Background And Purpose: Uncomfortable care and histamine H2 antagonist (H2A) are implicated in precipitating delirium. In acute stroke, however, the need for them depends on stroke severity, an established risk factor for delirium. So, it is unclear whether care or H2A itself is responsible for delirium.

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Background And Purpose: Delirium frequently complicates acute stroke and worsens outcomes. Because delirium is potentially preventable, predicting its occurrence is essential. Although several prediction scores have been proposed, nurses need to quickly predict delirium in stroke care units (SCUs).

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In eye movement examination, video-oculographic monocular recording has become more popular than electro-oculographic binocular recording. The aim of this study was to examine the characteristics of monocular movements recorded using video-oculography. In 66 healthy subjects, the horizontal saccades and smooth pursuit eye movements of the right eye within a range of 30º were evaluated using a video-oculographic eye movement recording system.

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Background: The utility of light transmission aggregometry (LTA)-based assessment of platelet function in acute ischemic stroke patients remains controversial. This study aimed to clarify why LTA failed to estimate platelet function in acute ischemic stroke patients.

Methods: Using LTA, we evaluated the platelet aggregation abilities of citrated blood samples from 22 acute noncardiogenic ischemic stroke patients prior to treatment and compared them with those of 65 heathy volunteer controls.

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