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Dive into the research topics where Hiroaki Oguro is active.

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Featured researches published by Hiroaki Oguro.


Stroke | 2011

Microbleeds Are Associated With Subsequent Hemorrhagic and Ischemic Stroke in Healthy Elderly Individuals

Hirokazu Bokura; Reiko Saika; Takuya Yamaguchi; Atsushi Nagai; Hiroaki Oguro; Shotai Kobayashi; Shuhei Yamaguchi

Background and Purpose— Cerebral microbleeds (MBs) are frequently detected in patients with stroke, especially those who experience intracerebral hemorrhage. However, the clinical significance of MBs in subjects without cerebrovascular disease is still unclear. We performed a prospective study to determine whether the presence of MBs provides useful prognostic information in healthy elderly individuals. Methods— We tracked 2102 subjects (mean age, 62.1 years) over a mean interval of 3.6 years after they voluntarily participated in the brain checkup system at the Shimane Institute of Health Science. An initial assessment was performed to document the presence of MBs and silent ischemic brain lesions and to map the location of the MBs. During the follow-up period, we obtained information about stroke events that occurred in each subject. Results— MBs were detected in 93 of the 2102 subjects (4.4%). Strokes occurred in 44 subjects (2.1%) during the follow-up period. They were significantly more common among subjects with MBs. Age and hypertension were independent risk factors for MBs. The presence of MBs was more strongly associated with a deep brain hemorrhage (hazard ratio, 50.2; 95% CI, 16.7 to 150.9) than ischemic stroke (hazard ratio, 4.48; 95% CI, 2.20 to 12.2). All hemorrhagic strokes occurred in deep brain regions, and they were associated with MBs located in the deep brain region. Conclusions— This longitudinal study demonstrated that the presence of MBs can be used to predict hemorrhagic and ischemic stroke, even in healthy elderly individuals.


Stroke | 2008

Metabolic Syndrome Is Associated With Silent Ischemic Brain Lesions

Hirokazu Bokura; Shuhei Yamaguchi; Kenichi Iijima; Atsushi Nagai; Hiroaki Oguro

Background and Purpose— Metabolic syndrome (MetS) is a recognized risk factor for stroke, but it is unclear whether MetS is also related to subclinical ischemic lesions. We examined the association of MetS with the prevalence of silent brain infarction, periventricular hyperintensity, and subcortical white matter lesions in healthy adults. Methods— We conducted a cross-sectional study in 1151 Japanese healthy subjects. Three types of silent lesions were assessed by MRI scans. MetS was diagnosed using the criteria by the National Cholesterol Education Adult Treatment Panel III. Results— After adjusting for age and other factors, MetS was significantly associated with silent brain infarction, periventricular hyperintensity and subcortical white matter lesions. Among the MetS components, elevated blood pressure was commonly associated with all types of lesions. Dyslipidemia and elevated fasting glucose levels were associated with subcortical white matter lesions and periventricular hyperintensities, respectively. Positive trends were observed between the number of MetS components and prevalence of silent lesions. Conclusions— MetS is associated with the prevalence of silent lesions independent of other risk factors. The clustering of MetS components tends to increase the prevalence of silent lesions.


Journal of Neurology | 1999

Medication-induced hallucination and cerebral blood flow in Parkinson's disease.

Kazunori Okada; Nobuo Suyama; Hiroaki Oguro; Shuhei Yamaguchi; Shotai Kobayashi

Abstract Although hallucinations in Parkinson’s disease (PD) are not unusual in the long-term treatment with anti-parkinsonian agents, their mechanism is not fully understood. We compared both the neuropsychiatric state and the results of 99mTc-labeled hexamethyl propyleneamine oxime single-photon emission computed tomography in 12 PD patients with medication-induced hallucinations and 21 PD patients without hallucinations. Hallucinatory patients showed significantly lower cerebral blood flow in left temporal regions than nonhallucinatory patients. The cerebral blood flow reduction in these regions may be related to the mechanism of medication-induced hallucinations in PD.


Cerebrovascular Diseases | 2011

Post-Stroke Apathy and Hypoperfusion in Basal Ganglia: SPECT Study

Keiichi Onoda; Yoko Kuroda; Yasushi Yamamoto; Satoshi Abe; Hiroaki Oguro; Atsushi Nagai; Hirokazu Bokura; Shuhei Yamaguchi

Background: Although apathy has been reported as one of the neuropsychiatric symptoms following stroke, there are few studies on regional cerebral blood flow (rCBF) in stroke patients with apathy. The present study compared rCBF between apathetic and non-apathetic patients after stroke. Methods: We recruited 102 patients with cerebral infarction within 1 month after stroke and performed neuropsychiatric assessments that included the apathy scale. rCBF was quantitatively measured using N-isopropyl-p-123I-iodoamphetamine single-photon emission computed tomography. Results: Thirty-seven patients (36%) had apathy. The apathetic group showed lower cognitive function and a higher depressive state than the non-apathetic group. rCBF in the basal ganglia was reduced for the apathetic group compared with the non-apathetic group. Furthermore, lesions in the left basal ganglia were associated with hypoperfusion in bilateral basal ganglia and the presence of apathy. Conclusion: These findings demonstrate that apathy is a frequent symptom among stroke patients and that hypoperfusion caused by basal ganglia lesions may contribute to post-stroke apathy.


Clinical Interventions in Aging | 2013

Validation of a new mass screening tool for cognitive impairment: Cognitive Assessment for Dementia, iPad version

Keiichi Onoda; Tsuyoshi Hamano; Yoko Nabika; Atsuo Aoyama; Hiroyuki Takayoshi; Tomonori Nakagawa; Masaki Ishihara; Shingo Mitaki; Takuya Yamaguchi; Hiroaki Oguro; Kuninori Shiwaku; Shuhei Yamaguchi

Background We have developed a new screening test for dementia that runs on an iPad and can be used for mass screening, known as the Cognitive Assessment for Dementia, iPad version (CADi). The CADi consists of items involving immediate recognition memory for three words, semantic memory, categorization of six objects, subtraction, backward repetition of digits, cube rotation, pyramid rotation, trail making A, trail making B, and delayed recognition memory for three words. The present study examined the reliability and validity of the CADi. Methods CADi evaluations were conducted for patients with dementia, healthy subjects selected from a brain checkup system, and community-dwelling elderly people participating in health checkups. Results CADi scores were lower for dementia patients than for healthy elderly individuals and correlated significantly with Mini-Mental State Examination scores. Cronbach’s alpha values for the CADi were acceptable (over 0.7), and test–retest reliability was confirmed via a significant correlation between scores separated by a one-year interval. Conclusion These results suggest that the CADi is a useful tool for mass screening of dementia in Japanese populations.


Journal of Neurology | 2006

Differentiating Alzheimer’s disease from subcortical vascular dementia with the FAB test

Hiroaki Oguro; Shuhei Yamaguchi; Satoshi Abe; Yuri Ishida; Hirokazu Bokura; Shotai Kobayashi

BackgroundThe frontal assessment battery (FAB) test is a composite tool for assessing executive functions related to the frontal lobe. Neuropsychological and blood-flow studies indicate distinct patterns of deterioration of anterior and posterior cortical function in Alzheimer’s disease (AD) and subcortical vascular dementia (VD) patients. We predict that the FAB score may be useful for discriminating VD from AD.ObjectiveTo evaluate the clinical usefulness of the FAB test for differential diagnosis of AD and VD.MethodsWe compared FAB scores in 25 patients with AD, 27 patients with VD, and 80 age-matched normal control subjects. The AD group was matched for age, education and MMSE score with the VD group. The subtest scores in FAB were also compared among the three groups.ResultsThe FAB scores were significantly decreased in both the AD and VD groups compared to the control group, and the reduction were greater in the VD group. Among the FAB subtests, mental flexibility (phonological verbal fluency) was the only subtest that significantly discriminated VD from the other two groups.ConclusionsThe FAB test can provide useful information for differentiating AD and VD at the bedside.


Dementia and Geriatric Cognitive Disorders | 2010

The Association of Metabolic Syndrome with Executive Dysfunction Independent of Subclinical Ischemic Brain Lesions in Japanese Adults

Hirokazu Bokura; Atsushi Nagai; Hiroaki Oguro; Shotai Kobayashi; Shuhei Yamaguchi

Background/Aims: The aim of this study is to examine whether metabolic syndrome is directly associated with cognitive impairment independent of subclinical ischemic brain lesions. Methods: We examined 1,543 neurologically normal subjects (44–86 years of age). Metabolic syndrome, brain MRI, and cognitive functions including general cognition and executive function were assessed. Results: After adjusting for silent brain lesions and demographic risk factors, metabolic syndrome was an independent risk factor for impairment of executive function (OR = 1.41, 95% CI = 1.17–1.25 for Kohs’ Test; OR = 2.25, 95% CI = 1.64–3.07 for Frontal Assessment Battery). Among the components of metabolic syndrome, elevated fasting glucose was the only independent risk factor for impairment of executive function. Conclusion: Metabolic syndrome is associated with impairment of executive function independent of silent brain lesions in the Japanese population.


Gerontology | 2004

Decline of Vertical Gaze and Convergence with Aging

Hiroaki Oguro; Kazunori Okada; Nobuo Suyama; Kazuya Yamashita; Shuhei Yamaguchi; Shotai Kobayashi

Background: Disturbance of vertical eye movement and ocular convergence is often observed in elderly people, but little is known about its frequency. Objective: The purpose of this study was to investigate age-associated changes in vertical eye movement and convergence in healthy elderly people, using a digital video camera system. Methods: We analyzed vertical eye movements and convergence in 113 neurologically normal elderly subjects (mean age 70 years) in comparison with 20 healthy young controls (mean age 32 years). The range of vertical eye movement was analyzed quantitatively and convergence was analyzed qualitatively. Results: In the elderly subjects, the angle of vertical gaze decreased with advancing age and it was significantly smaller than that of the younger subjects. The mean angle of upward gaze was significantly smaller than that of downward gaze for both young and elderly subjects. Upward gaze impairment became apparent in subjects in their 70s, and downward gaze impairment in subjects in their 60s. Disturbance in convergence also increased with advancing age, and was found in 40.7% of the elderly subjects. Conclusion: These findings indicate that the mechanisms of age-related change are different for upward and downward vertical gaze. Digital video camera monitoring was useful for assessing and monitoring eye movements.


Journal of Clinical Neuroscience | 2010

Successful treatment of post-stroke apathy by the dopamine receptor agonist ropinirole

Naoto Kohno; Satoshi Abe; Genya Toyoda; Hiroaki Oguro; Hirokazu Bokura; Shuhei Yamaguchi

Dopamine D2/3 receptor agonists have been widely used to treat motor symptoms in Parkinsons disease and are also reported to improve cognitive and emotional disturbances. Here we describe a patient who developed severe apathy after cerebral infarction in the prefrontal cortex. After administration of ropinirole, his verbal output and spontaneity in daily life was improved remarkably. This improvement was associated with increased blood flow in the prefrontal cortex and basal ganglia. We suggest that ropinirole may be a treatment option for deficits in motivated behavior after prefrontal damage.


Journal of Stroke & Cerebrovascular Diseases | 2013

Gastroesophageal Reflux during Enteral Feeding in Stroke Patients: A 24-hour Esophageal pH-monitoring Study

Yukie Satou; Hiroaki Oguro; Yo Murakami; Keiichi Onoda; Shingo Mitaki; Chizuko Hamada; Ryo Mizuhara; Shuhei Yamaguchi

BACKGROUND Patients who are unable to eat or drink after stroke may receive percutaneous endoscopic gastrostomy (PEG) or nasogastric tube feeding. Although the most common serious complication is well known to be aspiration pneumonia, the role of gastroesophageal reflux (GER) has not been fully assessed. The aim of this study was to examine, by means of 24-hour esophageal pH monitoring, whether GER is related to aspiration pneumonia and whether the size and laterality of brain lesions influence GER. METHODS Sixteen stroke patients were examined using a Degitrapper pH400 (Medtronic Japan Co., Tokyo, Japan) and Zinetics 24ME multiuse pH catheter (Medtronic). All patients had stroke lesions in the territory of the left or right middle cerebral artery that were confirmed by magnetic resonance imaging (MRI) and were receiving PEG or nasogastric feeding. Stroke volume was measured with MRIcron software. RESULTS Nine patients (56%) were diagnosed with GER, and 10 (63%) developed aspiration pneumonia after enteral feeding. The rate of aspiration pneumonia was significantly higher in patients with GER (88.9%) than in those without GER (42.9%; P = .04). Patients with left hemispheric lesions had a significantly higher incidence of acid reflex than those with right lesions (116 ± 105 vs 13 ± 17; P = .04). There were no significant differences in total time of acid reflux or mean pH value between patients with left and right hemispheric lesions. The lesion volume had no significant effect on any of 3 indices of GER. CONCLUSIONS GER is associated with aspiration pneumonia and occurs more often in patients with stroke lesions in the left hemisphere.

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