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Shuhei Yamaguchi

Publications and source records attributed to Shuhei Yamaguchi.

At least 19 recordsLinked to original sources
PubMed2006

Somatosensory disinhibition and frontal alien hand signs following medial frontal damage.

We report augmentation of somatosensory evoked potentials (SEP) in a patient with frontal alien hand signs after left medial frontal lobe damage. The SEP components occurring later than 30 msec post stimuli were enhanced over the parietal and frontal scalp sites of the lesioned hemisphere. This finding suggests that deficits in inhibitory control of somatosensory processing in parietal and frontal lobes contributes in some way to frontal alien hand signs.

Aged, 80 and over↗
PubMed2006

Hepatic iron overload associated with a decreased serum ceruloplasmin level in a novel clinical type of aceruloplasminemia.

BACKGROUND & AIMS: Aceruloplasminemia is a novel hereditary iron overload disease caused by a mutation in the ceruloplasmin gene and characterized by a complete deficiency of serum ceruloplasmin and iron accumulation in the liver and brain. METHODS: We herein studied a novel clinical type of aceruloplasminemia in which a low amount of ceruloplasmin was detected in the serum of a patient. The patient presented with an asymptomatic hepatic iron overload, retinal degeneration, and diabetes mellitus. Magnetic resonance imaging of the liver and basal ganglia showed T2-hypointensity signals associated with parenchymal iron accumulation because of an absence of the ferroxidase activity in ceruloplasmin. RESULTS: A gene analysis showed a novel G969S mutation in the ceruloplasmin gene. A biochemical analysis of the patients' serum and a biogenesis study of G969S mutant ceruloplasmin using mammalian cell culture system resulted in the synthesis and secretion of only apoceruloplasmin without any ferroxidase activity. CONCLUSIONS: This novel clinical type of aceruloplasminemia should therefore be considered in the differential diagnosis of unexplained hemochromatosis, which is associated with a decrease in the serum ceruloplasmin level.

Aged↗
PubMed2006

[Effect of sarpogrelate in enteral feeding of patients with gastroesophageal reflux (GER)].

AIM: Enteral feeding of patients who are unable to eat or drink because of neurological disorders finally undergo percutaneous endoscopic gastrostomy (PEG) or nasogastric tube feeding. Their most common serious complication is aspiration pneumonia. Our objectives were to evaluate the effect of sarpogrelate (a 5-HT2A receptor blocker) on gastroesophageal reflux (GER) in these patients. METHODS: This study was performed in 5 elderly patients, aged 70-87 years with neurological disorders (stroke 4, post herpes encephalitis 1), on PEG or nasogastric feeding for 5 weeks-1 year. A 48-hour esophageal pH study was performed using the Degitrapper pH400 (Medtronic Co.). The pH monitor catheter was passed into the esophagus transnasally and positioned with the pH electrode 5cm above the lower esophageal sphincter. During the first 24 hours drug no drug was given, and during the next 24 hours we gave 100mg sarpogrelate 3 times. We analyzed the frequency of acid reflux (when the pH in the esophagus become less than 4.0 for more than 5 seconds, we defined this is 1 episode of acid reflux), frequency of acid reflux and mean pH values between drug-on and drug-off periods. An upright position was maintained for two hours after each meal. RESULTS: When the results of pH monitoring during two half days (from 7 pm to 7 am: 12 hours) was compared between drug-on term and drug-off term, mean pH value was statistically elevated from 6.0 +/- 0.2 (drug-off) to 6.5 +/- 0.4 (drug-on) (mean +/- SD, p< 0.05). Frequency and the total time of acid reflex showed no difference between the two periods. CONCLUSION: Treatment with sarpogrelate might be effective in patients with GER by blocking activated serotonin receptor in the gastrointestinal system.

Aged↗
PubMed2006

[Clinical characteristics and prognosis in stroke patients with diabetes mellitus: retrospective evaluation using the Japanese Standard Stroke Registry database (JSSRS)].

We studied clinical characteristics and prognosis in acute stoke patients with diabetes mellitus registered on the Japanese Standard Stroke Registry database. A total of 16,630 acute stroke patients admitted to 56 hospitals in Japan. They were examined as to their stroke types, risk factors, their severity of stroke according to the NIH Stroke Scale (NIHSS) and Japan Stroke Scale (JSS), and outcomes by the modified Rankin Scale (m-RS). The incidence of subarachnoid hemorrhage was relatively high in the group of patients who had neither hypertension nor diabetes, and the incidence of brain hemorrhage was higher in the group of patients who had hypertension without diabetes. The frequencies of lacunar infarct and atherothrombotic infarct were also higher in the group of patients who had both hypertension and diabetes. In the diabetic group without hypertension, there were less numbers of hemorrhagic stroke. The ratio of good prognosis (m-RS 0-1) was significantly smaller in the diabetic patients with lacunar infarction, cardioembolic infarction, and subarachnoid hemorrhage. Additionally, there was significantly more stroke recurrence in the diabetic patients (33.0% vs. 26.9%, p<0.0001). The diabetic patients who received insulin therapy (-0.8 +/- 7.4), diet therapy (-0.4 +/- 9.4), or oral medicine (-0.9 +/- 7.2), showed significantly less improvements in the NIHSS compared to the non-diabetic patients (-1.6 +/- 8.2), respectively. Moreover, the poor-management diabetic patients showed significantly less improvements in the JSS compared to non diabetic patients (3.8 +/- 7.7 vs. 4.8 +/- 8.6, p<0.005). In conclusions, stroke patients with diabetes mellitus showed more stroke recurrence and resulted in poorer functional recovery compared to patients without diabetes.

Aged↗
PubMed2005

Event-related potentials for response inhibition in Parkinson's disease.

This study investigated inhibitory function in patients with Parkinson's disease (PD) by recording event-related brain potentials (ERPs) during a Go/NoGo task. Fourteen healthy volunteers and 13 patients with PD without dementia performed a cued continuous performance test that included Go and NoGo trials. The peak latency, amplitude, and topographic distributions of the ERPs to Go and NoGo stimuli were analyzed. Cognitive function was evaluated using the Wisconsin Card Sorting Test (WCST), Kana Pick-out Test, and Verbal Fluency Test (VFT). Performances in the WCST and VFT were significantly impaired in the PD group as compared with the control group. The PD group had significantly higher rates of omission and commission errors during the ERP task. The ERP study found no differences in the latency and amplitude of the Go-P3 between the two groups. By contrast, the NoGo-P3 latency was significantly longer in the PD group than in the control group. The amplitudes of the NoGo-P3 and NoGo-N2 were also significantly smaller in the PD group than in the control group. The NoGo-P3 latency was significantly correlated with the Kana Pick-out Test and VFT scores. The NoGo-P3 amplitude was significantly correlated with the WCST and VFT scores, as well as with the number of commission errors. There were no significant correlations between the cognitive function tests and either the Go-P3 or NoGo-N2 measures. The behavioral and ERP data suggest that there is selective impairment of inhibitory function in PD and that this deficit may be related to impaired inhibitory executive function in the frontal lobe.

Aged↗
PubMed2005

[Acute divergence paralysis in the Miller Fisher syndrome].

We experienced a 53-year-old man diagnosed as Miller Fisher syndrome (MFS) associated with anti-GQ1b and anti-GT1a antibodies. He presented acute divergence paralysis, bulbar palsy, ascending hyperesthesia, areflexia and diminished vibration sense. External ophthalmoplegia and convergence paralysis were not seen, but he noticed double vision when looking at an object from the distance of more than 70 cm away on a day 10 of hospitalization. Hess chart test revealed an esotropic pattern, so the diagnosis of divergence palsy was made. Brain MRI was normal. Neurological deficits were treated with plasma exchange, resulting in favorable outcome. Divergence paralysis could be one of the clinical manifestations for MFS and might be due to nuclear or supranuclear damge of vergence-related neurons.

Acute Disease↗
PubMed2005

[Intravenous tissue plasminogen activator (t-PA) for acute ischemic stroke in a local university hospital].

Thrombolytic therapy for ischemic stroke has not been approved in Japan yet. However, we have used intravenous t-PA for acute ischemic stroke patients. We reviewed the clinical data on patients who were treated with intravenous t-PA and entered in the stroke registry of our hospital between April 1999 and March 2004. Of 408 acute ischemic stroke patients, 20 patients (mean age 73.6 +/- 10.9, male 15, female 5) were given intravenous t-PA (alteplase in 18 patients and monteplase in two patients). The baseline NIH Stroke Scale (NIHSS) and Japan Stroke Scale (JSS) scores were 17.5 (median) and 13.3 +/- 7.6 (mean), respectively. The NIHSS and JSS at discharge were 12.5 and 12.1 +/- 11.8, respectively. Symptomatic intracerebral hemorrhage occurred in one patient. The rate of favorable outcome (mRS 0-3) at 90 days was 40%. The rate of favorable outcome at 90 days in our study was lower than that in reported randomized trials of intravenous t-PA, such as the NINDS study or the ATIANTIS trial, perhaps because age and baseline severity were higher in our patients than in the subjects in these trials. Another reason may be the dose of t-PA. As we concerned about the occurrence of symptomatic intracranial hemorrhage and there are no data on appropriate dose of t-PA for Japanese patients, the dose of t-PA that we used was 0.4 mg/kg in most patients. Although five patients died in our study, the cause of death in four patients was not hemorrhagic transformation but deteriorating ischemic infraction. The dose of t-PA that we used may have been safe but a little low for thrombolysis.

Age Factors↗
PubMed2005

Effects of aging on regional cerebral blood flow assessed by using technetium Tc 99m hexamethylpropyleneamine oxime single-photon emission tomography with 3D stereotactic surface projection analysis.

OBJECTIVES: Although many previous reports have described age-related changes in regional cerebral blood flow (rCBF), none has used 3D stereotactic surface projection (3D-SSP) analysis, which is able to detect subtle and significant changes in rCBF. METHODS: The subjects were 31 healthy volunteers (16 men and 15 women; 50-79 years of age) without abnormal MR imaging and MR angiographic findings, cognitive impairment, or depression. For each subject, rCBF was evaluated by using technetium Tc 99m-radiolabeled hexamethylpropyleneamine oxime single-photon emission CT. Maps of rCBF were compared among different age groups (50-59, 60-69, and 70-79 years of age) by using 3D-SSP. The mean z score for each gyrus was calculated for each age group by using a recently developed stereotactic extraction estimation method. RESULTS: Significant age-related reductions in rCBF were seen in the bilateral cingulate gyri, left inferior gyrus, bilateral medial frontal gyri, left subcallosal gyrus, and left superior temporal gyrus. Extensive and constant reduction in rCBF occurred with increasing age in the bilateral anterior cingulate gyri, and the mean z score for this region was the highest among all the regions examined. CONCLUSION: The 3D-SSP analysis revealed that the greatest reduction in rCBF occurred within the bilateral anterior cingulate gyri in normal middle-aged and older subjects.

Aged↗
PubMed2004

Impaired novelty processing in apathy after subcortical stroke.

BACKGROUND AND PURPOSE: Apathy is associated with decreased novelty-seeking behaviors and is a prevailing behavioral symptom after stroke affecting cortical and subcortical regions. We studied the relationship between apathetic state after subcortical stroke and neural orienting response to novel events using an event-related evoked potential (ERP) technique. METHODS: Twenty-nine patients with subcortical ischemic stroke were grouped according to whether they showed apathy or not. We analyzed apathy state scaled by the modified Starkstein apathy score and auditory P3 ERP components evoked by task-relevant target stimuli (target P3) and task-irrelevant novel stimuli (novelty P3). RESULTS: The apathetic group showed a significantly lower score of verbal fluency test and global cognitive function test compared with the nonapathetic group. The novelty P3 latency was significantly prolonged, and its amplitude was reduced over the frontal site in the apathy group. The apathy scale was correlated with the novelty P3 latency and amplitude at the frontal site. The target P3 measures were related to global cognitive function. CONCLUSIONS: The present study suggests that apathy after subcortical stroke is associated with impaired neural processing of novel events within the frontal-subcortical system and that the novelty P3 is a useful physiological measure for assessing apathy after stroke.

Affect↗
PubMed2004

Rapid prefrontal-hippocampal habituation to novel events.

Unexpected novel events generate an orienting response that plays an important role in some forms of learning and memory. The orienting response involuntarily captures attention and rapidly habituates as events become familiarized. Although evidence from patients with focal lesions and scalp and intracranial event-related brain potential recordings supports the involvement of a distributed neural network involving association cortex and the limbic system in novelty detection, the key neural substrates and temporal dynamics have not been defined. While subjects performed a bi-field visual-selective attention task with random novel stimuli embedded in either attended or unattended visual fields, we measured rapid changes of regional blood oxygenation level-dependent (BOLD) signal to target and novel stimuli using single-trial analysis of event-related functional magnetic resonance imaging with a 4T scanner. Habituation was quantified by serial BOLD signal changes during the first 10 novel stimuli for each subject. Novel stimuli activated the bilateral superior/middle frontal gyrus, temporal-parietal junction, superior parietal lobe, cingulate gyrus, hippocampus, and fusiform gyrus. The superior/middle frontal gyrus and hippocampus showed significant reduction of BOLD signal during the first few novel stimuli, whereas the signals in the fusiform and cingulate gyrus were constant. Prefrontal and hippocampal responses to attended and unattended novel stimuli were comparably habituated. These results, and previous data from lesion studies, support the view that prefrontal and hippocampal regions are involved in rapid automatic detection and habituation to unexpected environmental events and are key elements of the orienting response in humans.

Adult↗
PubMed2004

Successful treatment with succinate in a patient with MELAS.

We present a case report of a 27-year-old man with MELAS, who presented with general convulsions and left flaccid hemiparesis. Anticonvulsant drugs failed to achieve complete control of his convulsions. A good response to oral administration of succinate has been maintained for more than 30 months, with no recurrence of any stroke-like episode. Succinate therapy may have potential for treatment of uncontrolled convulsive MELAS patients.

Administration, Oral↗
PubMed2004

Deterioration of vascular dementia caused by recurrent multiple small emboli from thoracic aortic atheroma.

We report a case of a 77-year-old man with deteriorating dementia caused by repeated multiple small cerebral embolisms from a thoracic aortic atheroma. Multiple small embolisms were confirmed by diffusion-weighted magnetic resonance imaging (DWI). The patient ultimately died due to aortic dissection. Pathological examinations revealed that no causative embolic source for multiple embolisms could be detected other than severe atheromatous ulcer in thoracic aorta. This case demonstrates that severe aortic atheroma has the potential to precipitate deterioration of vascular dementia.

Aged↗
PubMed2004

[Clinical characteristics of cerebral infarction in China and Japan].

In order to elucidate the clinical characteristics of cerebral infarction in a northeastern district of China, 1,353 patients with first-ever cerebral infarction in Shenyang, China, were compared with 2,929 patients registered in Japan. Using the identical database (Japan Standard Stroke Registry Study), we prospectively collected clinical data on acute ischemic stroke patients who were admitted to two main hospitals in Shenyang, China, and 50 hospitals in Japan. The mean age was 67.3 years in China and 71.3 years in Japan. Of the patients in China, 78% were classified as atherothrombotic infarction, 18% as lacunae, and 1% as cardioembolism. By contrast, 30% of the patients in Japan were classified as atherothrombotic infarction, 32% as lacunae, and 31% as cardioembolism. Regarding the risk factors, the incidence of hypertension was 76% in China and 62% in Japan. Diabetes mellitus was 10% in China and 26% in Japan. Hyperlipidemia was 10% in China and 22% in Japan. Atrial fibrillation was 3% in China and 21% in Japan. As the diagnostic criteria for hyperlipidemia differed, we could not compare this risk factor between the two countries statistically; however, cardioembolism, lacunae, and atrial fibrillation were significantly less common in China than in Japan. Our data suggest that hypertension is an important risk factor for ischemic stroke, and the incidence of cardioembolism and atrial fibrillation is very low in Shenyang, China.

Age Factors↗
PubMed2003

Event-related brain potential changes after Choto-san administration in stroke patients with mild cognitive impairments.

RATIONALE: Few drugs have been reported to be effective for the treatment of vascular dementia. Choto-san is a herbal medicine expected to be effective in this condition, but it is unclear how this drug modulates brain activities and cognitive functions. P3 event-related brain potentials (ERP) provide reliable electrophysiological indices for some aspects of cognitive functions. OBJECTIVES: We measured P3 ERP to assess the effect of Choto-san administration on stroke patients with mild cognitive impairments. METHODS: Choto-san was given for 12 weeks to ten chronic stroke patients. P3 ERP were recorded before and after drug administration in a modified auditory oddball paradigm including occasional novel sounds using a high-density array EEG recording system. The reproducibility of ERP was also assessed in other ten stroke patients with a 12-week interval. Cognitive functions were assessed with the Mini Mental State Examination (MMSE) and verbal fluency test. RESULTS: Twelve-week administration of Choto-san significantly improved MMSE and verbal fluency test scores. The reproducibility of P3 latency and amplitude to target and novel sounds was excellent. P3 latency to target sounds was shortened in association with reduced reaction time to the sounds after drug administration. Furthermore, P3 amplitude to novel sounds was enlarged and its topography shifted from central to frontal sites. CONCLUSIONS: These results indicate that Choto-san improves electrophysiological indices related to attention and decision making, in addition to neuropsychological test scores in stroke patients with mild cognitive impairments.

Aged↗
PubMed2002

Electroencephalographic activity in a flanker interference task using Japanese orthography.

The neural activities for color word interference effects were investigated using event-related brain potentials (ERPs) recorded in a flanker-type interference task. Kanji words (Japanese morphograms) and kana words (Japanese phonograms) were used as the flanker stimuli to obtain insights about hemispheric specialization for processing two types of Japanese orthographies. Interference effects in reaction time were larger when kanji words were presented in the left visual field and when kana words were in the right visual field. ERPs were modulated by the incongruent flankers, which generated a negative ERP component with the different onset and offset depending on flanker attributes. Consistent with the behavioral data, the interference-related negativity was observed for kanji words presented in the left visual field and for kana words in the right visual field. The negativity distributed maximally over the fronto-central site. The early part of the negativity distributed strongly over the frontal midline area, whereas it extended bilaterally over the frontal area in the late phase. The present results support the view of preferential processing of kanji in the right hemisphere and that of kana in the left hemisphere. The temporal profile of scalp topographies for the interference-related neural activity suggests that the medial and dorsolateral prefrontal regions may be involved in maintaining attentional set and conflict resolution.

Adult↗
PubMed2002

Frequency and pathogenesis of silent subcortical brain infarction in acute first-ever ischemic stroke.

OBJECTIVES: We have often observed silent subcortical brain lesions on CT or MRI in first-ever ischemic stroke, but there is little published information on the relationship of these lesions to stroke subtypes. Here, we describe the incidence of MRI-detected silent subcortical brain lesions, including infarctions and white matter lesions, in a series of patients with first-ever ischemic stroke classified according to stroke subtypes. We also discuss the pathogenesis of these silent subcortical lesions. PATIENTS: We evaluated 171 patients with acute first-ever ischemic stroke. METHODS: The subjects were divided into three groups: lacunar, atherothrombotic and cardioembolic infarction groups. We evaluated silent subcortical brain infarction (SSBI), enlargement of perivascular space (EPS), and other white-matter lesions using MRI. RESULTS: Hypertension was observed in 67.6% of lacunar infarction, 57.1% of atherosclerotic infarction, and 54.1% of cardioembolic infarction. SSBI was more frequently observed in lacunar infarction than the others (lacunar vs. atherothrombotic vs. cardiogenic infarction, 81.5% vs. 44.4% vs. 42.1%, p=0.006). High-grade EPS (grade 2 or higher) was also observed more frequently in lacunar infarction than in the others (lacunar vs. atherothrombotic vs. cardiogenic infarction, 63.3% vs. 24.2% vs. 0%, p<0.001). Scheltens' score of silent subcortical lesions was significantly higher in lacunar infarction than in the others. CONCLUSIONS: The frequency of silent subcortical ischemic brain lesions was significantly higher in lacunar infarction than in atherosclerotic or cardioembolic infarction. We suggest that the pathogenesis of silent subcortical ischemic brain lesions is common to that of lacunar infarction, that is, small-vessel vasculopathy.

Adult↗