Ryusaku Hashimoto

Prevalence and Cognitive Performances of Clinical Dementia Rating 0.5 and Mild Cognitive Impairment in Japan. The Tajiri Project

The borderline zone condition between normal aging and dementia is a major issue of concern. Although the term mild cognitive impairment (MCI) is popular, its prevalence and neuropsychological features have not been fully investigated. We investigated the prevalence and neuropsychological features for Clinical Dementia Rating (CDR) 0.5 and MCI. For normal aging, the effects of age and educational level on cognitive performance were examined. We examined 1501 older residents (46.8%) in Tajiri 65 years of age and older. They performed the Cognitive Abilities Screening Instrument (CASI). Depressive scores and subjective memory complaints were also evaluated. There was no age effect but an educational effect on cognitive performance in healthy adults. We found the overall prevalence of CDR 0.5 to be 30.2%, whereas that of MCI was only 4.9%. All CASI domains were deteriorated except for long-term memory and visual construction in the CDR 0.5 participants compared with healthy adults, suggesting that CDR 0.5 is similar to very mild Alzheimer disease. Memory complaints’ data suggested that it would be better to exclude memory complaints from the MCI criteria. We considered that the concept of CDR 0.5 would be more applicable to community residents rather than that of the MCI.

Effect of age and education on the Trail Making Test and determination of normative data for Japanese elderly people : The Tajiri Project

Abstract  The Trail Making Test (TMT) is a common two‐part neuropsychological test, in which visuospatial ability (TMT‐A) and executive function (TMT‐B) are evaluated. Normative data for this test have not been reported for Japanese subjects; therefore, the purpose of the present paper was to investigate the effect of age and education on the TMT in 155 healthy elderly adults with clinical dementia rating 0 (healthy). The participants were classified into three groups based on age (70–74 years, 75–84 years and ≥85 years), and also into three groups based on educational level (6 years, 8 years and ≥10 years). The time to complete TMT‐A and TMT‐B were measured, and the difference in score between TMT‐A and TMT‐B (B–A) and the ratio of the score (B/A) were calculated as indices of executive function. The time for completion of both parts of the TMT increased markedly in the ≥85‐years group. For TMT‐A, there was a significant difference between the 6‐years and 8‐years groups, and between the 6‐years and ≥10‐years groups, and for TMT‐B, there was a significant difference between the 6‐years and ≥10‐years groups, and between the 8‐years and ≥10‐years groups. The difference and ratio scores increased in the ≥85‐years group, but the educational level did not significantly influence these scores. Our data suggest that cognitive functions evaluated by TMT‐A and TMT‐B are not affected by aging until the subjects are ≥85 years old. For TMT‐A, an educational effect becomes apparent when the population includes poorly educated subjects, but this part of the test is not affected by educational level provided that the subjects have some education (>6 years). The time to complete TMT‐B is affected by educational level, consistent with previous reports. However, when adjusted using the results for TMT‐A [(B‐A) or (B/A)], the educational effect on executive function disappeared. Thus, the effect of educational level on executive function was unclear in normal elderly subjects.

Non-verbal learning is impaired in very mild Alzheimer's disease (CDR 0.5): normative data from the learning version of the Rey-Osterrieth Complex Figure Test.

Abstract  Mild cognitive impairment (MCI) is a transitional state between normal aging and dementia. Although there have been some studies on the role of verbal memory in learning ability, there have been no reports on the part played by visual memory. In the present study, the Rey–Osterrieth Complex Figure Test (RCFT) was given to healthy subjects and to those with MCI to determine if visual memory was maintained in these two groups. Additionally, normative data from the learning version of the RCFT for Japanese subjects were examined, for purpose of reference. The participants consisted of 381 clinical dementia rating (CDR) 0 subjects and 137 CDR 0.5 subjects who could perform the full set of RCFT tasks. The CDR 0 group had significantly higher scores than the CDR 0.5 group in all trials. The CDR 0 participants also showed a significant step‐by‐step learning effect, while the CDR 0.5 participants did not show a significant learning effect. These results suggest that the CDR 0 participants maintained intact learning abilities of encoding and retrieval, while the CDR 0.5 participants did not do so; but further studies will be needed to clarify these findings.

The role of the dorsolateral prefrontal cortex in deception when remembering neutral and emotional events

We used functional magnetic resonance imaging (fMRI) to investigate the neural correlates of deception while remembering neutral events and emotional events. Before fMRI, subjects were presented with a series of neutral and emotional pictures and were asked to rate each picture for arousal. During fMRI, subjects were presented with the studied and nonstudied pictures and were asked to make an honest recognition judgment in response to half of the pictures and a dishonest response to the remaining half. We found that deception pertaining to the memory of neutral pictures was associated with increased activity in the bilateral dorsolateral prefrontal cortex, the left ventrolateral prefrontal cortex, and the left orbitofrontal cortex. We also found that deception while remembering emotional pictures was associated with increased activity in the bilateral dorsolateral prefrontal cortex. An overlapping activation between the two types of deception was found in the bilateral dorsolateral prefrontal cortex. Our results indicate that the dorsolateral prefrontal cortex is associated with the executive aspects of deception, regardless of the emotional valence of memory content.

A Validation Study of the Japanese Version of the Addenbrooke's Cognitive Examination-Revised.

The aim of this study was to validate the Japanese version of the Addenbrooke’s Cognitive Examination-Revised (ACE-R) [Mori: Japanese Edition of Hodges JR’s Cognitive Assessment for Clinicians, 2010] designed to detect dementia, and to compare its diagnostic accuracy with that of the Mini-Mental State Examination. The ACE-R was administered to 85 healthy individuals and 126 patients with dementia. The reliability assessment revealed a strong correlation in both groups. The internal consistency was excellent (α-coefficient = 0.88). Correlation with the Clinical Dementia Rating sum of boxes score was significant (rs = –0.61, p < 0.001). The area under the curve was 0.98 for the ACE-R and 0.96 for the Mini-Mental State Examination. The cut-off score of 80 showed a sensitivity of 94% and a specificity of 94%. Like the original ACE-R and the versions designed for other languages, the Japanese version of the ACE-R is a reliable and valid test for the detection of dementia.

Executive dysfunction can explain word‐list learning disability in very mild Alzheimer's disease: The Tajiri Project

Abstract  Elderly people with questionable dementia (i.e. a Clinical Dementia Rating (CDR) of 0.5) have been focused on as representing the borderline zone condition between healthy people and dementia patients. Many of them are known to have pathologic traits of very mild Alzheimers disease (AD). Although they present mild memory disorder, the underlying mechanism has not been fully investigated. Herein is reported the mechanism of learning disability in very mild AD. Eighty‐six CDR 0.5 participants and 101 age‐ and education‐matched healthy controls (CDR 0) were randomly selected from a community in the town of Tajiri, Miyagi Prefecture. The word‐recall task of the Alzheimer Disease Assessment Scale–Japanese (i.e. learning and recall of 10 words) was administered. The numbers of words recalled in each trial and those never recalled throughout the trials were compared for the two CDR groups. The serial‐position function was depicted for three parts (i.e. primary, middle, and recency). The CDR 0.5 group recalled significantly fewer words than the CDR 0 group. The number of never‐recalled words was greater in the CDR 0.5 group. A remarkable difference was found in the middle part of the word list. The number of never‐recalled words of the CDR 0.5 group was greater in the middle part. The large number of never‐recalled words accounted for the poor learning performance of very mild AD participants. The results suggested that very mild AD participants have difficulty in learning and retaining words in the middle part of the word‐list because of a functional decline of the central executive system.

Confabulations in Episodic Memory Are Associated With Delusions in Alzheimer’s Disease:

Although confabulations and delusions are observed in Alzheimer’s disease, the relationship between the 2 has not been fully investigated. This study involved 50 patients with Alzheimer’s disease and 10 healthy participants. After the patients were divided into delusional and nondelusional groups, confabulations and cognitive function were assessed. No confabulations appeared in the healthy participants, and only patients with Alzheimer’s disease showed confabulations. The delusional group produced more confabulations on episodic subjects than on semantic subjects. There was a correlation between cognitive impairment and confabulations in semantic memory. These findings suggest that different mechanisms are involved in confabulations between semantic and episodic memories.

The neural basis of dishonest decisions that serve to harm or help the target

We conducted a functional magnetic resonance imaging (fMRI) study to elucidate the neurocognitive mechanisms of harmful and helpful dishonest decisions. During scanning, the subjects read scenarios concerning events that could occur in real-life situations and were asked to decide whether to tell a lie as though they were experiencing those events. Half of the scenarios consisted of harmful stories in which the dishonest decisions could be regarded as bad lies, and the other half consisted of helpful stories in which the dishonest decisions could be regarded as good lies. In contrast to the control decision-making task, we found that the decision-making tasks that involved honesty or dishonesty recruited a network of brain regions that included the left dorsolateral prefrontal cortex. In the harmful stories, the right temporoparietal junction and the right medial frontal cortex were activated when the subjects made dishonest decisions compared with honest decisions. No region discriminated between the honest and dishonest decisions made in the helpful stories. These preliminary findings suggest that the neural basis of dishonest decisions is modulated by whether the lying serves to harm or help the target.

Changing the criteria for old/new recognition judgments can modulate activity in the anterior hippocampus

Numerous functional magnetic resonance imaging (fMRI) studies have reported that the medial temporal lobe (MTL) is activated to a greater extent when subjects encounter novel items as compared with familiar ones. However, it remains unclear whether the novelty signals in the MTL are modulated by the criteria for old/new recognition judgments. In this study, we used fMRI to test our hypothesis that when subjects encounter items similar to previously encountered ones, the novelty signals in the MTL will differ depending on whether the subjects focus on the perceptual features or the semantic aspects of the items. The subjects studied a series of photographs and were later asked to make a recognition judgment of (a) Same items (items identical to those seen during encoding), (b) Similar items (items similar to but not identical to those seen during encoding), and (c) New items (unstudied items) in two types of tasks: Perceptual and Semantic. The subjects judged whether the items were perceptually identical to those seen during encoding in the Perceptual task and whether the items were semantically identical to those seen during encoding in the Semantic task. The left anterior hippocampus was activated when subjects were presented with New items relative to Same items in both tasks. In addition, the hippocampal activity in response to the Similar items was increased only in the Perceptual, but not the Semantic task. Our results indicate that the novelty signals in the hippocampus can be modulated by criteria for old/new recognition judgments.

Yellow Glasses Improve Contrast Sensitivity of a Patient with a Visual Variant of Alzheimer’s Disease

Yellow Glasses Improve Contrast Sensitivity of a Patient with a Visual Variant of Alzheimer’s Disease Shinya Sakai a, Kazumi Hirayama a, Syoichi Iwasaki b, Toshikatsu Fujii a, Ryusaku Hashimoto a, Atsushi Yamadori a Division of a Neuropsychology, Department of Disability Medicine, Tohoku University Graduate School of Medicine, and bGraduate School of Information Sciences, Tohoku University, Sendai, Japan