Eunjoo Lee

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.

Confabulations on episodic and semantic memory questions are associated with different neurologic backgrounds in Alzheimer disease.

BackgroundThe neurologic background of confabulations with reference to delusions or cognitive functions has not been clarified in Alzheimer disease (AD). MethodsConfabulations of 41 AD patients and 12 healthy controls were studied using the Modified Confabulation Battery. The mini-mental state examination and Cognitive Abilities Screening Instrument were used for cognitive evaluations. Cerebral atrophy was assessed by voxel-based–morphometry of magnetic resonance imaging and the correlations with confabulations were analyzed by statistical parametric mapping 2. For the relations with delusion, the AD patients were divided into the delusion and nondelusion groups. The single photon emission computed tomography was performed to evaluate cerebral blood flow and the group difference was analyzed by statistical nonparametric mapping 3. ResultsThe AD patients exhibited more confabulations on episodic memory questions compared with semantic questions. The semantic confabulation scores correlated with mini-mental state examination and most Cognitive Abilities Screening Instrument domains scores, and correlated with atrophy in the anterior cingulate, bilateral medial temporal, and right middle temporal gyrus. The delusion group exhibited more episodic confabulations and had lower prefrontal blood flow than the nondelusion group. ConclusionsDifferent mechanisms are involved in confabulations between semantic and episodic memories in AD. Episodic confabulation is affected by delusion related to frontal dysfunction, and semantic confabulation is associated with cognitive dysfunction.

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.

Ontogeny of protein kinase C in the rat hippocampus: an autoradiographic study with [3H]phorbol 12,13-dibutyrate

The ontogeny of protein kinase C (PKC) in the hippocampus was studied in 1-week-, 4-week-, and 3-month-old Wistar rats with in vitro receptor autoradiography using [3H]phorbol 12,13-dibutyrate ([3H]PDBu). The developmental pattern of [3H]PDBu binding varied within hippocampal subregions. [3H]PDBu binding in stratum oriens of the CA1 and CA3 sectors and stratum lucidum of the CA3 sector increased to adult levels by 4 weeks. In strata moleculare and granulosum of the dentate gyrus, the binding reached peak values at 4 weeks but declined at 3 months. Interestingly, in stratum lacunosum-moleculare of the CA1 sector, the [3H]PDBu binding activity was the highest at 1 week. There were constant binding activities in stratum radiatum of the CA1 and CA3 sectors and the dentate hilus during the postnatal development. These findings may provide evidence that PKC has a distinct role in different subregions of the hippocampus during postnatal development.

SLEEP DEPRIVATION INDUCES COGNITIVE DYSFUNCTION THROUGH MECHANISM INVOLVED IN NEUROINFLAMMATION AND OXIDATIVE STRESS

SAMP8 mice 11 months of age were injected with metformin or vehicle daily, after 4 weeks, mice were tested in T-maze foot shock avoidance, object recognition and Barnes maze. At the end of all three studies brain tissue was collected for oxidative stress analysis. Results: Topiramate improved T-maze acquisition at 0.1 and 0.01 mg/kg. It had no effect on memory in object recognition. Topiramate decreased superoxide dismutase (SOD), 4-hydroxynoneal (HNE) and 3-nito-tyrosine (3-NT) in brain tissue indicating a reduction in oxidative stress in the brain. Topirmate at 0.1mg/kg in the SAMP8 mice improved T-maze foot shock avoidance acquisition (0.1 mg/kg) and retention (1.0 mg/kg) and retention on the 5 day probe test in the Barnes maze (0.1 mg/kg). Metformin improved both acquisition and retention in T-maze foot shock avoidance, retention in object recognition and acquisition in the Barnes maze. Conclusions: Topiramate improved learning and memory both diabetic and the SAMP8 model of AD. Metformin improved learning and memory in the mouse model of AD. The current results suggest that topiramate may have therapeutic potential for diabetes and AD andmetforminmay have therapeutic potential in AD.