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Hsiu-Chih Liu

Publications and source records attributed to Hsiu-Chih Liu.

32 records · Page 2Linked to original sources
PubMed2003

Generalized Kohonen's competitive learning algorithms for ophthalmological MR image segmentation.

Kohonen's self-organizing map is a two-layer feedforward competitive learning network. It has been used as a competitive learning clustering algorithm. In this paper, we generalize Kohonen's competitive learning (KCL) algorithm with fuzzy and fuzzy-soft types called fuzzy KCL (FKCL) and fuzzy-soft KCL (FSKCL). These generalized KCL algorithms fuse the competitive learning with soft competition and fuzzy c-means (FCM) membership functions. We then apply these generalized KCLs to MRI and MRA ophthalmological segmentations. These KCL-based MRI segmentation techniques are useful in reducing medical image noise effects using a learning mechanism. They may be particularly helpful in clinical diagnosis. Two real cases with MR image data recommended by an ophthalmologist are examined. First case is a patient with Retinoblastoma in her left eye, an inborn malignant neoplasm of the retina frequently metastasis beyond the lacrimal cribrosa. The second case is a patient with complete left side oculomotor palsy immediately after a motor vehicle accident. Her brain MRI with MRA, skull routine, orbital CT, and cerebral angiography did not reveal brainstem lesions, skull fractures, or vascular anomalies. These generalized KCL algorithms were used in segmenting the ophthalmological MRIs. KCL, FKCL and FSKCL comparisons are made. Overall, the FSKCL algorithm is recommended for use in MR image segmentation as an aid to small lesion diagnosis.

Algorithms↗
PubMed2003

The three-item clock-drawing test: a simplified screening test for Alzheimer's disease.

The Clock-Drawing Test (CDT) has been used to screen for Alzheimer's disease (AD) as a supplement to cognitive tests that focus on memory impairment. We examined a comprehensive scoring system of the CDT in screening of AD in a Chinese population and derived a simplified scoring system. All 403 (144 AD and 259 nondemented) subjects were administered the CDT, including both the drawing part (CDT-D) and the copying part (CDT-C). The Cognitive Abilities Screening Instrument and the Clinical Dementia Rating were also administered. Stepwise discriminant analysis was used to develop a simplified CDT scoring system. The optimal CDT cutoff scores (CDT-D: 10/11; CDT-C: 12/13) show intermediate sensitivity (CDT-D: 66.7%; CDT-C: 51.4%) and specificity (CDT-D: 74.5%; CDT-C: 74.1%). The simplified 3-item CDT scoring system, with a cutoff score of 2/3, has a sensitivity of 72.9% and a specificity of 65.6%; it can be used as a quick test for AD screening.

Adult↗
PubMed2003

Statistical parametric mapping of brain SPECT perfusion abnormalities in patients with Alzheimer's disease.

Brain perfusion in 20 patients with mild Alzheimer's disease (AD), 20 patients with moderate AD and 20 control subjects (matched for age, gender and education) were assessed by single photon emission computed tomography (SPECT) using technetium-99m hexamethylpropylene amine oxime ((99m)Tc-HMPAO). SPECT images were transformed to a standard size and shape for group comparisons by the voxel-based t test of the statistical parametric mapping techniques. Cerebral hypoperfusion in the left lower parietal area was found in mild AD patients. In moderate AD patients, significant cerebral hypoperfusion was located in bilateral posterior parietotemporal cortices, contiguous anterior occipital lobes, posterior cingulate gyri and, to a lesser extent, in frontal areas.

Aged↗
PubMed2003

Selective hypoperfusion of anterior cingulate gyrus in depressed AD patients: a brain SPECT finding by statistical parametric mapping.

This study tests the hypothesis that depression in patients with Alzheimer's disease (AD) is due to a specific pathogenesis rather than a reactive phenomenon. Forty-three AD patients received a psychiatrist's interview, neuropsychological assessments, and a 99mTc-hexamethyl propyleneamine oxime single photon emission computed tomography (HMPAO-SPECT). Analysis by statistical parametric mapping (SPM) showed that the depressed group had selective hypoperfusion in the bilateral anterior and posterior cingulate gyri and precuneus. Using the Hamilton Depression Rating Scale as a parameter, an inverse correlation was found between cerebral perfusion and the severity of depression. The right anterior cingulate gyrus demonstrated a most significant reduction in perfusion. These locations are akin to the imaging findings in patients with primary depression, indicating a specific pathogenesis for depression in AD.

Aged↗
PubMed2003

Smoking and cognitive performance in the community elderly: a longitudinal study.

This prospective study investigated the association between smoking and cognitive performance in a community of nondemented elderly subjects aged 65 or older. All subjects were categorized as current smokers, former smokers, or never smokers. The lifetime cigarette exposure was computed. At baseline, we found the abstainers from smoking had better cognitive performances; however, the differences were not significant after adjusting for age, education, hypertension, diabetes, and vascular events. The lifetime cigarette exposure was not predictive of the cognitive status. At a 3-year follow-up, neither the smoking status nor the lifetime cigarette exposure predicted the declination of cognition.

Aged↗
PubMed2002

Study of the association between Alzheimer's disease and angiotensin-converting enzyme gene polymorphism using DNA from lymphocytes.

Angiotensin-converting enzyme (ACE) may play a role in cognition and memory. A recent study found that a 287-bp insertion/deletion (I/D) polymorphism of the ACE gene is associated with susceptibility to Alzheimer's disease (AD). However, this finding has not been replicated by all studies. These discrepancies may be due to the difference in ethnic background. Therefore, we investigated the possibility of such an association in 173 AD patients and 286 normal controls from a Chinese population. We found that there is an increased frequency of the ACE I allele in AD patients and the odds ratio for bearers of the I allele was 2.88. Our findings further support previous reports of an association between ACE polymorphism and AD. The implication of the ACE I/D polymorphism in the pathogenesis of AD warrants further exploration.

Adult↗
PubMed2002

The Alzheimer's Disease Assessment Scale: findings from a low-education population.

We constructed a Chinese version of the cognitive component of the Alzheimer's Disease Assessment Scale (ADAS-Cog). In order to accommodate illiteracy, the Chinese version used pictures instead of words for assessing recall and recognition. The Chinese ADAS-Cog was administered to 125 individuals with no dementia, 127 with questionable dementia, and 77 with Alzheimer's disease (AD). Their age range was 51-92 years and their education range was 0-20 years. The Chinese ADAS-Cog had high internal consistency (Cronbach's alpha = 0.87) and very high interrater reliability (intraclass correlation coefficient, or ICC, = 0.99) and test-retest reliability (ICC = 0.96). It had high correlations with scores on the Clinical Dementia Rating Scale (Pearson's r = 0.85), the Cognitive Abilities Screening Instrument (CASI, Pearson's r = -0.88), and CASI-estimated scores on the Mini-Mental State Examination (Pearson's r = -0.85). Performance on the Chinese ADAS-Cog was uninfluenced by age or gender, nor by education level except within the low education range of 0-6 years. Its memory items were best for early detection of dementia; its language items were best for monitoring the progression of dementia. This study found that the Chinese ADAS-Cog is a good instrument for use with Chinese AD patients.

Aged↗
PubMed2002

Association analysis for the genetic variants of the NMDA receptor subunit 2b and Alzheimer's disease.

N-methyl-D-aspartate (NMDA) receptor dysfunction has been implicated in the pathogenesis of Alzheimer's disease (AD). The NMDA receptor is composed of several subunits, of which the receptor 2b subunit (NR2b) is of particular significance for AD. Abundant in the hippocampus of normal subjects, reductions in NR2b have been demonstrated in the hippocampus and entorhinal cortex of AD patients. In this study, we tested the hypothesis that the allelic variant (C2664T) of the NR2b confers susceptibility to AD using a sample population of 132 AD patients and 114 normal controls. The distribution of the NR2b genotypes (p = 0.600) and alleles (p = 0.652) did not differ significantly between AD patients and controls, however, suggesting that it is unlikely that the NR2b C2664T polymorphism plays a substantial role in conferring susceptibility to AD. We propose that other genetic variations of the NMDA subunits, relating either to AD or to the therapeutic response for NMDA partial agonists, may need further investigation.

Aged↗
PubMed2002

Performance on the cognitive abilities screening instrument at different stages of Alzheimer's disease.

The Cognitive Abilities Screening Instrument (CASI) contains nine cognitive domains. Its total score has been used to screen for dementia in epidemiological studies conducted in the US, Japan and Taiwan, but its usefulness in distinguishing different levels of dementia has not been examined. This study was conducted to compare CASI scores of patients with Alzheimer's disease (AD) with different levels of severity of dementia. The CASI was administered to 475 AD patients with mild, moderate or severe dementia according to the Clinical Dementia Rating Scale. The patients' scores were compared to the scores of 475 age-, education- and gender-matched control subjects. More specifically, each patient's score, X, was transformed to a z score with reference to the mean and SD of the scores of the control group, where z = (X - mean)/SD. Then, the mean of the z scores and the percentage of patients with z scores of <-2.0 were compared among the three patient groups. For the CASI total score and all of its nine domain scores, the mean z score decreased (except that for short-term memory) and a higher percentage of patients scored below the normal range with increasing severity of dementia. This study validates the usefulness of the CASI for assessing the severity of dementia. The domain scores differed in their relative usefulness for detecting dementia and for distinguishing in different levels of dementia.

Alzheimer Disease↗
PubMed2002

Cutoff scores of the cognitive abilities screening instrument, Chinese version in screening of dementia.

The purpose of this study of dementia screening was to obtain different cutoff scores of the Cognitive Abilities Screening Instrument, Chinese versions (CASI C-2.0) for subjects with different educational backgrounds. The diagnosis of dementia was based on the Diagnostic and Statistical Manual of Mental Disorders, ed 3 revised or ed 4 criteria. To diagnose Alzheimer's disease, the guidelines of the National Institute of Neurological and Communicative Disorders and Stroke and Alzheimer's Disease and Related Disorders Association was followed. The severity of dementia was determined on the Clinical Dementia Rating scale. Altogether 2,096 subjects, aged 65 years and more, were included. Of them, 1,178 were normal and 918 were demented. Their performance on CASI C-2.0 was influenced by their education and age. Gender difference on CASI C-2.0 scores was only significant in the illiterate, but not in the literate group. We recommend that the population be divided into three levels, namely those who (1) had no formal education (Edu = 0); (2) received 1-5 years of schooling (Edu = 1-5), and (3) received 6 or more years of education (Edu >/=6). The cutoff scores of CASI C-2.0 in the diagnosis of dementia in these three educational groups were as follows: Edu = 0: 49/50 (sensitivity = 0.83; specificity = 0.85); Edu = 1-5: 67/68 (sensitivity = 0.83; specificity = 0.91), and Edu >/=6: 79/80 (sensitivity = 0.89; specificity = 0.90).

Aged↗
PubMed2002

Association study for Parkinson's disease and a dopamine transporter gene polymorphism (1215A/G).

The dopamine transporter (DAT) may play a role in the pathogenesis of Parkinson's disease (PD) because dopamine-specific neurotoxins are taken into dopaminergic nerve terminals via the DAT. A recent study has demonstrated that a DAT polymorphism in exon 9 (1215A/G) is associated with susceptibility to PD. This finding was not replicated by another study, however. Therefore, the significance of this association was tested using a Chinese sample population consisting of 102 PD patients and 174 controls, together with the association for onset age. Comparing the two groups, neither the genotypic (p = 0.272) nor allelic frequencies (p = 0.209) were statistically different. Further, the mean onset age was not significantly different for PD patients comparing the DAT genotypes (p = 0.925). Our findings confirm those of the previous negative report and, taken together, suggest that the DAT polymorphism (1215A/G) does not play a major role in the susceptibility to PD. Other DAT genetic variants, and the association of these variants with PD symptomatology or treatment response, may merit further investigation.

Age of Onset↗
PubMed2002

Lack of association between the apolipoprotein E genotype and depression in Alzheimer's disease.

The epsilon4 allele of apolipoprotein (apo E) is one of the risk factors for late-onset Alzheimer's disease (AD). We evaluated the association between apo E genotypes and depression in patients with AD. A psychiatrist interviewed all patients and their caregivers for depression using a Chinese version of the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, and for the severity of depression using the Hamilton Depression Rating Scale (HDRS). Twenty-five of the 149 patients with AD were diagnosed with depressive disorders. The numbers of patients in each apo E genotype were 10 in epsilon2/3, 2 in epsilon2/4, 74 in epsilon3/3, 46 in epsilon3/4, and 17 in epsilon4/4. We did not find an association between depression and the presence or absence of the epsilon4 or epsilon2 allele. The HDRS scores were not different in patients with AD with the epsilon4 or epsilon2 allele or in those patients without them. Our study did not find an association between depression and the apo E epsilon4 or epsilon2 allele in AD.

Age of Onset↗