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Biomedical subjects

A Yamadori

Publications and source records attributed to A Yamadori.

At least 19 recordsLinked to original sources
PubMed2001

Judging semantic and episodic incongruity: a magnetoencephalographic study.

Evoked magnetic fields over the entire head were measured during a semantic judgment task, in which conditions of the pre-test learning session were manipulated. Subjects learnt related and unrelated category-noun pairs, and were then asked to judge the relationship between category and noun. Unrelated pairs evoked activation around 400 ms in the left temporal area. In addition, newly presented related pairs, of which the categories were used to learn unrelated pairs, also evoked similar activities. Our findings suggest that these activities are not only related to the semantic incongruity between a pair of words as in previous studies, but also to the episodic incongruity between the learning and measurement sessions.

Adult↗
PubMed2001

Elderly Japanese emigrants to Brazil before World War II: I. Clinical profiles based on specific historical background.

OBJECTIVE: To research the demographic and clinical profiles of elderly Japanese emigrants, who arrived in Brazil before World War II, in order to give them appropriate psychogeriatric care. DESIGN: Elderly Japanese immigrants aged 65 years and over, belonging to the Miyagi Association in the São Paulo Metropolitan Area, were targeted. They emigrated from Miyagi Prefecture to Brazil and are now living in the area. We were able to interview 166 respondents. All data were gathered using standardized interview methods covering (a) free interview about the immigration history, (b) demographics, and (c) physical status. RESULTS: Through the free interview, we found their immigration histories, which affected their clinical profiles. The mean age and educational level were 77.5 years and 6.3 years, respectively. Sixty per cent of them immigrated when they were younger than 14. Ninety-four per cent of them still keep Japanese nationality. Fifty-seven per cent of them usually use Japanese, while 10% of them use Portuguese. Although their emigration histories were hard, 76% of them perceived their health as being excellent or relatively good. The percentages of subjects with histories of disease were hypertension, 52.5%; cardiac disease, 20.8%; diabetes mellitus, 24.2%; and hyperlipidemia, 25.0%, which were affected by the Brazilian environment. CONCLUSION: The elderly Japanese who emigrated to Brazil before World War II have a unique historical and demographic background. Their clinical profiles cannot be fully understood without knowing their histories. They definitely need high quality international psychogeriatric care.

Age Distribution↗
PubMed2001

Elderly Japanese emigrants to Brazil before World War II: II. Prevalence of senile dementia.

BACKGROUND: We previously showed the prevalence of dementia in the town of Tajiri (Miyagi Prefecture, Japan), and found it to be 8.0%. The first population-based study on dementia in Brazil (Catanduva) disclosed the prevalence as being 7.1%. To evaluate the effects of environment on development of dementia, elderly Japanese immigrants living in Brazil were examined. Brazil is the country with the largest number of Japanese immigrants. METHODS: All immigrants aged 65 years and over from Miyagi Prefecture, living in the four cities of the São Paulo Metropolitan area were targeted (n = 192). We were able to examine 166 subjects (86.5%). The diagnosis of dementia was based on the DSM-IV with the severity assessed by the CDR (clinical dementia rating) scales. The cognitive ability screening instrument (CASI) was used for neuropsychological assessment. RESULTS: Thirteen subjects were diagnosed with dementia, CDR 1-3, the prevalence being 7.8%. Older subjects suffered more from dementia, and, paradoxically, the more highly educated subjects also suffered more. All the CASI items, except for long-term memory and visual construction, significantly deteriorated in the CDR 0.5 group compared with the CDR 0 group. COMMENTS: The prevalence of dementia was not thought to be affected by environmental factors. A paradoxically higher rate of dementia in the more educated subjects was probably due to the historical problems of the immigrants. Intact CASI item long-term memory in the CDR 0.5 group indicated that suspected dementia patients could maintain this function. This is the first epidemiological study on dementia in elderly Japanese immigrants in Brazil.

Age Distribution↗
PubMed2001

Depressive symptoms and associated factors in a cognitively normal elderly population: the Tajiri Project.

BACKGROUND AND OBJECTIVE: Since depression is one of the main problems of elderly subjects, it is important to examine the prevalence of this condition and to identify associated factors. METHODS: A total of 1525 cognitively normal subjects aged 65 years and over in the town of Tajiri, a typical agricultural town in Japan, were analysed. Their MMSE (mini-mental state examination) scores were 24 or over. Depressive state was assessed by Zung's SDS (self-rating depression scale) with a comprehensive interview to examine ADL, demographics and symptoms associated with illness, etc. The prevalence of depression was calculated. To determine the factors associated with depression, the t-test and the Chi-square test were used. To examine the relative strength of each factor, logistic regression analysis was performed. RESULTS: The ratio of the depressive subjects was 6.4%, lower than those of previous reports, probably due to the effect of excluding dementia subjects. The ratio for older females aged 80 years and over was 14.3%, which was significantly higher than that of the males. Among socio-demographic factors, sex, age, number of children and perception of economic status, were significantly related. For health status and ADL, such factors as perception of health and medical history of heart disease and rheumatism were related. For familial and social status, factors such as daily activity and several conversation abilities were related. The logistic regression analysis indicated that perception of health and daily activity were associated. CONCLUSIONS: In this study, we isolated some factors related to depression in a cognitively normal population. Knowledge of such factors is important for appropriate mental care of aged subjects.

Activities of Daily Living↗
PubMed2001

The influence of misnaming on object recognition: a case of multimodal agnosia.

We present a case of multimodal agnosia in the visual and tactile modality due to an infarction in the territory of the left posterior cerebral artery. The patient's ability to recognize objects fluctuated depending on his verbal activity. When he misnamed presented objects, he tended to use them and to draw them in keeping with the wrong name. We submit that the mechanism causing associative agnosia is more dynamic than it was hitherto considered. It originates from the rivalry between top-down central regulation and bottom-up peripheral flow.

Aged↗
PubMed2001

Pure Kana agraphia as a manifestation of graphemic buffer impairment.

We report a left-handed man who demonstrated a pure agraphia limited to words written in Kana characters (syllabograms) following a right putaminal hemorrhage. Writing words in Kanji characters (logograms) was well preserved. His performance in Kana writing was characterized by intact ability to write single syllables, error increase in the second half of words directly proportional to the word length and correct but slow writing of words using kana blocks. Errors were more prominent in Hiragana words than Katakana words which are usually used to transcribe foreign words. Acoustic-grapheme sequencing per se was not impaired as shown by his correct performance in arranging character blocks. These findings suggest selective damage to the graphemic buffer, a module that temporarily maintains the graphemic representation elaborated in previous stages before it is sent to the peripheral systems for its motor realization.

Aged↗
PubMed2001

Neuroanatomical discrimination between manipulating and maintaining processes involved in verbal working memory; a functional MRI study.

We used functional magnetic resonance imaging (fMRI) to investigate neural correlates of processes concerning store and manipulation in verbal working memory. We prepared a revised lag 1 digit span, digit span and a simple number detection task. Specific activities in association with manipulating process were identified in the right middle (BA 9/46) and left precentral gyrus (BA 6). Activated areas specific to maintaining process were detected in the right middle (right BA 11/10) and medial (BA 6) frontal gyri, the right inferior parietal lobule (BA 40), and the left middle (BA 9) and inferior frontal gyri (BA 44). The process-nonspecific activated areas common to two processes were identified in the right inferior frontal gyrus (BA 47) and the left superior parietal lobule (BA 7). Using the signal percent change of each subject, we calculated the correlation coefficients among each activated area. The results of this analysis showed that two processes of verbal working memory were clearly discriminated. The two essential processes of manipulation and maintenance in working memory seem to activate process-specific and overlapping (process-nonspecific) areas, but the patterns of combination were definitely different.

Adult↗
PubMed2001

A 5-year retrospective examination of cognitive screening test stages in normal older adults and patients with Alzheimer's disease: the Tajiri project.

One conception of aging and cognitive deterioration is that cognitive decline becomes common with age, and dementia may be regarded as one extreme of the continuum. An alternative conception is that the cognitive process is spared by the aging process itself and that cognitive functioning of normal older adults and those with slight cognitive impairment, a CDR (Clinical Dementia Rating) score of 0.5 (suspected dementia), should be different. We examined changes in the screening test performances of 170 older adults over a 5-year period and found the following: (a) The CDR 0 (normal) participants did not show remarkable changes even in the older groups and (b) the subitems of orientation, memory, and so forth were useful for distinguishing normal older adults from early Alzheimer's disease patients. The results support the idea that dementia is better conceptualized as an age-related than as an "aging-related" disorder and that a CDR score of 0.5 should be considered very mild Alzheimer's disease.

Aged↗
PubMed2001

Isolated and focal retrograde amnesia: a hiatus in the past.

Two cases of isolated retrograde amnesia were reported. Both showed the same clinical pattern in development and resolution of amnesia despite of different etiologies. Sudden insult to the brain (trauma in Case 1 and viral encephalitis in Case 2) caused concurrent antero- and retrograde amnesia. Fortunately both recovered from the anterograde amnesia completely. However, both were left with a period of postictal amnesia of a few months and retrograde amnesia of up to 14 months' duration. The analysis of their pattern of temporal evolution and dissolution of amnesia support the hypothesis that recently acquired episodic information requires a certain amount of constant activation for a certain period of time in order to be organized into a durable memory. The nature of this activation as well as its origin remains to be solved.

Accidents, Traffic↗
PubMed2001

Ideomotor apraxia in patients with Alzheimer disease: why do they use their body parts as objects?

OBJECTIVE: Difficulty in pantomiming the use of tools is observed in patients with Alzheimer disease. Patients with Alzheimer disease tend to use their body parts as objects when they try to pantomime the use of tools. The body-parts-as-objects phenomenon was thought to consist of appropriate gross movement of patients' arms despite inappropriate patterns of handling tools with their hands. However, the mechanism has not been investigated fully. METHODS: The authors examined 11 healthy individuals and 24 patients with Alzheimer disease for ability to recognize tools, to pantomime the use of tools, to use actual tools, and to select an appropriate photograph of a handling pattern of the tool. RESULTS: In comparison with the patients with Alzheimer disease, the healthy individuals had higher scores for all tasks. The authors classified the patients into group A (patients with higher pantomime scores), group B (patients with middle level scores), and group C (patients with lower scores). Frequency of use of body parts as objects for patients in group B was higher than that of patients in group A and in group C. The mean Mini-Mental State Examination score for patients in group A was higher than that of patients in group B and in group C. In comparison with patients in group A, patients in group B showed lower scores on the hand-posture discrimination task without a tool, even after controlling the Mini-Mental State Examination score. CONCLUSIONS: The authors conclude that body-parts-as-objects responses in patients with Alzheimer disease occur because general cognition is lowered or because retrieval ability of the appropriate holding posture for tools is impaired.

Aged↗
PubMed2001

[A case of crossed aphasia with echolalia after the resection of tumor in the right medial frontal lobe].

We report a right-handed woman, who developed a non-fluent aphasia after resection of astrocytoma (grade III) in the right medial frontal lobe. On admission to the rehabilitation department, neurological examination revealed mild left hemiparesis, hyperreflexia on the left side and grasp reflex on the left hand. Neuropsychologically she showed general inattention, non-fluent aphasia, acalculia, constructional disability, and mild buccofacial apraxia. No other apraxia, unilateral spatial neglect or extinction phenomena were observed. An MRI demonstrated resected areas in the right superior frontal gyrus, subcortical region in the right middle frontal gyrus, anterior part of the cingulate gyrus, a part of supplementary motor area. Surrounding area in the right frontal lobe showed diffuse signal change. She demonstrated non-fluent aprosodic speech with word finding difficulty. No phonemic paraphasia, or anarthria was observed. Auditory comprehension was fair with some difficulty in comprehending complex commands. Naming was good, but verbal fluency tests for a category or phonemic cuing was severely impaired. She could repeat words but not sentences. Reading comprehension was disturbed by semantic paralexia and writing words was poor for both Kana (syllabogram) and Kanji(logogram) characters. A significant feature of her speech was mitigated echolalia. In both free conversation and examination setting, she often repeated phrases spoken to her which she used to start her speech. In addition, she repeated words spoken to others which were totally irrelevant to her conversation. She was aware of her echoing, which always embarrassed her. She described her echolalic tendency as a great nuisance. However, once echoing being forbidden, she could not initiate her speech and made incorrect responses after long delay. Thus, her compulsive echolalia helped to start her speech. Only four patients with crossed aphasia demonstrated echolalia in the literature. They showed severe aphasia with markedly decreased speech and severe comprehension deficit. A patient with a similar lesion in the right medial frontal lobe had aspontaneity in general and language function per se could not be examined properly. Echolalia related to the medial frontal lesion in the language dominant hemisphere was described as a compulsive speech response, because some other 'echoing' phenomena or compulsive behavior were also observed in these patients. On the other hand, some patients with a large lesion in the right hemisphere tended to respond to stimuli directed to other patients, so called 'response-to-next-patient-stimulation'. This behavior was explained by disinhibited shift of attention or perseveration of the set. Both compulsive speech responses and 'response-to-next-patient-stimulation' like phenomena may have contributed to the echolalia phenomena of the present case.

Adult↗
PubMed2000

Striatal dopaminergic transmission and neocortical glucose utilization in Alzheimer's disease: a triple-tracer positron emission tomography study.

The central dopaminergic neuron system is related to cognitive function and behavior. For Alzheimer's disease (AD), using PET and the ligands of dopa, D2 receptor antagonist, and deoxyglucose, we previously found that dopa uptake into the striatum (the Ki value) was correlated with the Mini-Mental State (MMS) score. AD patients exhibiting wandering had an increased level of D2 receptor (the k3/k4 value). The Ki value was correlated with glucose metabolism (CMRglc) of the frontal and temporal lobes, those of wanderers being lower than nonwanderers. We investigated the relationships between the Ki value and the k3/k4 value with reference to cognitive impairment and wandering. Using the three-tracer technique for the single subject, the Ki value, the k3/k4 value, and CMRglc in 12 AD patients were measured. For the wanderers, there was a reverse correlation between the Ki and the k3/k4 values. Multiple regression analysis showed that the score on the verbal fluency test was explained by the Ki value and CMRglc of the frontal and temporal lobes, while MMS score was related to more global areas.

Journal Article↗
PubMed2000

Retention of words in long-term memory: a functional neuroanatomical study with PET.

We used PET to identify brain regions associated with retention of verbal materials in long-term memory. During a PET scan, subjects repeated many sets of words one after another. In a retention condition, they were simultaneously required to retain 10 key words that were irrelevant to the repetition task. Significant increases in regional cerebral blood flow during the retention condition were found in bilateral parahippocampal regions, the left prefrontal and parietal association cortices, the supplementary motor area, the neostriatum and the cerebellum. We clearly demonstrated that retention of verbal materials was accompanied by neural activities in the medial temporal lobes. We also showed that, in the early phase, retention of words in long-term memory recruited left cortical areas surrounding those relevant to verbal short-term memory.

Acoustic Stimulation↗
PubMed2000

Atrophy of the corpus callosum correlates with white matter lesions in patients with cerebral ischaemia.

Many studies of white matter high signal (WMHS) on T2-weighted MRI have disclosed that it is related to cerebral ischaemia and to brain atrophy. Atrophy of the corpus callosum (CC) has also been studied in relation to ischaemia. Our objective was to test the hypothesis that CC atrophy could be due to ischaemia. We therefore assessed CC, WMHS and brain atrophy in patients with risk factors without strokes (the risk factor group) and in those with infarcts (the infarct group), to investigate the relationships between these factors. We studied 30 patients in the infarct group, 14 in the risk factor group, and 29 normal subjects. Using axial T1-weighted MRI, cortical atrophy and ventricular enlargement (brain atrophy) were visually rated. Using axial T2-weighted MRI, WMHS was assessed in three categories: periventricular symmetrical, periventricular asymmetrical and subcortical. Using the mid-sagittal T1-weighted image, the CC was measured in its anterior, posterior, mid-anterior and mid-posterior portions. In the normal group, no correlations were noted between parameters. In the infarct group, there were significant correlations between CC and brain atrophy, and between CC atrophy and WMHS. After removing the effects of age, gender and brain atrophy, significant correlations were noted between some CC measures and subcortical WMHS. In the risk factor group, there were significant correlations between CC and brain atrophy and between CC atrophy and WMHS. After allowance for age, gender and brain atrophy, significant correlations between some CC measures and periventricular WMHS remained. The hypothesis that CC atrophy could be due to cerebral ischaemia was supported by other analyses. Namely, for correlations between the extent of infarcts and partial CC atrophy in patients with anterior middle cerebral artery (MCA) and with posterior MCA infarcts, there were significant correlations between the extent of infarct and mid-anterior CC atrophy in the former, and posterior CC atrophy in the latter. Our findings could indicate that CC atrophy is associated with cerebral ischaemia.

Adult↗
PubMed2000

The nature of age-related decline on the reading span task.

We examined the effect of age on working memory with a reading span task (RST) together with other verbal span tasks. Sixty-two participants were divided into three subgroups (young, middle-aged, and elderly). The RST performances were significantly different among all the subgroups. To elucidate which component of the working memory system is affected by age, we performed an analysis of covariance with the scores of simple and complex verbal span tasks as covariates. From the results, we conclude that the difference of the RST performance between the middle-aged and elderly groups reflects a decline in the capacity of the phonological loop, and the difference between the young and middle-aged groups reflects malfunctioning of the central executive system.

Adult↗
PubMed2000

Intact verbal description of letters with diminished awareness of their forms.

Visual processing and its conscious awareness can be dissociated. To examine the extent of dissociation between ability to read characters or words and to be consciously aware of their forms, reading ability and conscious awareness for characters were examined using a tachistoscope in an alexic patient. A right handed woman with 14 years of education presented with incomplete right hemianopia, alexia with kanji (ideogram) agraphia, anomia, and amnesia. Brain MRI disclosed cerebral infarction limited to the left lower bank of the calcarine fissure, lingual and parahippocampal gyri, and an old infarction in the right medial frontal lobe. Tachistoscopic examination disclosed that she could read characters aloud in the right lower hemifield when she was not clearly aware of their forms and only noted their presence vaguely. Although her performance in reading kanji was better in the left than the right field, she could read kana (phonogram) characters and Arabic numerals equally well in both fields. By contrast, she claimed that she saw only a flash of light in 61% of trials and noticed vague forms of stimuli in 36% of trials. She never recognised a form of a letter in the right lower field precisely. She performed judgment tasks better in the left than right lower hemifield where she had to judge whether two kana characters were the same or different. Although dissociation between performance of visual recognition tasks and conscious awareness of the visual experience was found in patients with blindsight or residual vision, reading (verbal identification) of characters without clear awareness of their forms has not been reported in clinical cases. Diminished awareness of forms in our patient may reflect incomplete input to the extrastriate cortex.

Awareness↗