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Biomedical subjects

K Koivisto

Publications and source records attributed to K Koivisto.

At least 37 records · Page 2Linked to original sources
PubMed1996

Memory functions in human subjects with different apolipoprotein E phenotypes during a 3-year population-based follow-up study.

The apolipoprotein E epsilon4 allele is the most common risk factor for Alzheimer's disease (AD). The epsilon2 allele may play a protective role in AD. Our previous cross-sectional study showed that in non-demented elderly subjects the epsilon2 allele is associated with better learning ability than other alleles. We wished to investigate the influence of different apolipoprotein E (apoE) phenotypes on cognitive functions in a 3-year follow-up study starting with a random sample of 917 non demented elderly subjects. Episodic memory was examined with the List Learning Test (Buschke's selective reminding method), as well as with immediate and delayed recall of figures. Retrieval from semantic memory was assessed with the Category and Verbal Fluency tests. Constructional abilities were examined by copying figures. Attention functions were examined with the Trail Making A and B tests. A total of 632 subjects completed the 3-year follow-up study. The subjects with apoE phenotypes E2/2 or E2/3 were able to maintain their verbal learning performance, while the learning ability of the subjects with other apoE phenotypes deteriorated. We suggest that successful mental aging may be at least in part associated with genetic factors.

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PubMed1996

Prevalence of ageing-associated cognitive decline in an elderly population.

Different diagnostic definitions have been proposed for use in the characterization of mild cognitive disorders associated with ageing. Previously, we reported a high (38.4%) prevalence of age-associated memory impairment (AAMI) using the National Institute of Mental Health criteria in an elderly population. Recently, a work group of the International Psychogeriatric Association proposed criteria for 'ageing-associated cognitive decline' (AACD). The objective of this study was to evaluate the prevalence of AACD in an elderly population. We examined 403 randomly selected subjects (68-78 years of age) with tests of memory, cognitive processing, attention, verbal and visuoconstructive functions and with a structured questionnaire for health status and subjective complaints of cognitive decline. In all, 26.6% of the subjects (24.4% of women, 30. 1% or men) fulfilled the AACD criteria. The prevalence was slightly related to age and education. The rate was lowest in the oldest age of 75 - 78 years (20.5%) and highest in the age of 71 -74 years (30%). Subjects with less than 4 years of education had the lowest (14.3%) and subjects with more than 6 years of education had the highest rate (29.4%) for AACD. However, the differences between these subgroups were not statistically significant. These results suggest that the prevalence of AACD is lower than that of AAMI. As AAMI tends to identify a very heterogeneous subject group, the AACD diagnosis, which takes into account age and education specific norms in its inclusion criteria, might prove superior to AAMI in differentiating a meaningful subgroup from an elderly population both for research purposes and in clinical settings.

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PubMed1995

The association of apolipoprotein E polymorphism with memory: a population based study.

Several studies have shown an association between the apolipoprotein epsilon 4 allele and Alzheimer's disease (AD). The allele epsilon 2 has been associated with survival and longevity. We wanted to examine whether the relationship between cognitive efficiency and apolipoprotein E polymorphism (APOE) exists in a random sample of 916 non-demented elderly subjects. Episodic memory was examined with the list learning test, and with immediate and delayed recall of the figures. Semantic memory was examined with the Category and Verbal Fluency Tests. Constructional abilities were examined by copying the figures. Attention functions were examined with Trail Making A and B tests. We found that subjects with APOE E2/2 and 2/3 phenotypes showed better learning ability than those subjects with the APOE E2/4, 3/4 or 4/4 phenotypes. Impaired memory was not related to the excess of cardiovascular diseases in the subjects with APOE E2/4, 3/4, 4/4 phenotypes. Thus they may be associated, at least partly, with genetic factors.

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PubMed1995

Apolipoprotein E polymorphism and Alzheimer's disease in eastern Finland.

Apolipoprotein E is a polymorphic protein defined by three alleles, epsilon 2, epsilon 3 and epsilon 4. An increased frequency of the epsilon 4 allele is associated with late-onset familial and sporadic Alzheimer's disease (AD). We studied 202 Finnish AD patients and 55 age- and sex-matched controls. AD patients were divided into four subgroups; sporadic early-onset, sporadic late-onset, familial early-onset and familial late-onset disease. We found no significant differences in the epsilon 4 allele frequency between the subgroups. However, all the subgroups differed in the frequency of epsilon 4 allele detection from the controls (P < 0.0001). In the late-onset patients, the age at onset decreased from 76 to 69 as the number of epsilon 4 alleles increased from 0 to 2.

Age of Onset↗
PubMed1995

Habituation of auditory N100 correlates with amygdaloid volumes and frontal functions in age-associated memory impairment.

We studied the habituation of auditory N100 responses in subjects with age-associated memory impairment (AAMI) and in healthy age-matched volunteers. The findings were correlated with volumes of the amygdala, hippocampus, and frontal lobe measured by magnetic resonance imaging (MRI), as well as with subjects' performance on tests assessing frontal lobe functions and memory. Habituation of N100 did not differ across AAMI subjects and controls. However, in AAMI subjects there was a significant correlation between habituation of N100 and volumes of the amygdala; the more reduced habituation, the smaller volume. In addition, decline in habituation of N100 correlated with impaired performance on a visual memory test (Heaton Visual memory test (Heaton Visual Retention Test; r = 0.77; p < 0.001) and impairment on tests assessing frontal functions (Verbal Fluency, Trail Making Test, and Stroop). Habituation of N100 was not related to age or sex. To our knowledge this is the first study to demonstrate a relationship between habituation of evoked responses, MRI volumetric measures, and performance on psychometric tests. The results suggest that impaired memory and frontal lobe functions in AAMI subjects may be associated with poor habituation of N100. Since habituation reflects focusing of attention to relevant features of stimuli, impairment of this mechanism and subsequent defective memory trace formation may contribute to the observed deficits on memory tests.

Aged↗
PubMed1995

A follow-up study of age-associated memory impairment: neuropsychological predictors of dementia.

OBJECTIVE: To examine the clinical course of age-associated memory impairment (AAMI) and to evaluate the value of neuropsychological tests in predicting cognitive decline in AAMI subjects in a follow-up period of more than 3 years. DESIGN: Prospective cohort study. SETTING: The outpatient Memory Research Unit of the Department of Neurology at the University of Kuopio in Eastern Finland. PARTICIPANTS: A sample of 229 subjects (mean age 71.7 years) identified in two screening studies as having AAMI. MEASUREMENTS: A battery of neuropsychological tests and a structured inquiry for health status and subjective memory complaints were performed at baseline and follow-up to diagnose AAMI according to the criteria proposed by a National Institute of Mental Health work group. RESULTS: Of the 229 subjects, 176 (76.9%) participated in the follow-up for, on average, 3.6 years after the baseline. Of the participants, 104 (59.1%) still met the AAMI criteria. Other subjects were classified into five subgroups: (1) subjects showing decline in cognition meeting dementia diagnosis (16, 9.1% (13 of them AD)); (2) subjects with mild cognitive decline meeting neither dementia nor AAMI criteria (13, 7.4%); (3) subjects with memory performance now superior to AAMI criteria (17, 9.7%); (4) subjects having a disease classified as exclusion in the criteria (15, 8.5%); (5) subjects not now reporting subjective memory loss in everyday life (9, 5.1%). Two subjects (1.1%) were not classified because of incomplete data. Neuropsychological tests predicted which subjects would develop dementia during the follow-up period. The best discriminators between these subjects and those who remained AAMI were memory and verbal fluency tests. CONCLUSION: The study suggests that, in general, AAMI is nonprogressive, but the AAMI population also includes subjects with early dementia and subjects without genuine memory loss. However, these subjects can be differentiated with a more detailed neuropsychological evaluation.

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PubMed1995

Hemodynamic effects of carotid endarterectomy by magnetic resonance flow quantification.

BACKGROUND AND PURPOSE: Blood flow can be evaluated non-invasively using magnetic resonance phase-contrast flow quantification. The purpose of this prospective study was to assess the feasibility of this method and to evaluate the hemodynamic effects of carotid endarterectomy. METHODS: Volumetric flow rates and peak systolic velocities of the internal and common carotid and the vertebral arteries were measured by magnetic resonance flow quantification. Sixteen patients undergoing 18 endarterectomies had complete flow data recorded preoperatively and 3 days after surgery. RESULTS: The inverse correlation between the angiographic stenosis degree and the preoperative flow rate in the corresponding internal carotid artery was highly significant (r = -.69, P < .001). After endarterectomy, the mean flow in the ipsilateral internal carotid artery improved from 143 to 233 mL/min (P < .001). The mean peak systolic velocity increased from 23 to 37 cm/s (P < .001). No significant changes were seen in the contralateral carotid or the vertebral arteries. The mean total blood flow improved by 81 mL/min (P = .08). In the severely stenosed bifurcations (70% to 99%, n = 11), the flow rate improved by 106 mL/min and in the moderately (30% to 69%, n = 4) or mildly (< 30%, n = 3) stenosed bifurcations by 63 mL/min. If the contralateral carotid artery was occluded or severely stenosed, the improvement was 164 mL/min. CONCLUSIONS: Magnetic resonance flow quantification provides a useful tool for the follow-up of the hemodynamic effects of carotid endarterectomy. Our results indicate that surgery is followed by a significant increase of blood flow in the ipsilateral carotid artery and that there appear to be differences in flow increase between subgroups of patients with different degrees of stenosis.

Aged↗
PubMed1995

Prevalence of age-associated memory impairment in a randomly selected population from eastern Finland.

Aging has multiple effects on memory in normal subjects. However, information on the prevalence of age-associated memory impairment (AAMI) is scanty. We studied the prevalence of AAMI in a randomly selected population of 1,049 subjects aged 60 to 78 years from eastern Finland. Research criteria proposed by the National Institute of Mental Health (NIMH) Work Group were applied. We calculated prevalence rates for AAMI by the inclusion criteria alone (subjective and objective memory impairment and no dementia) as well as by the inclusion and exclusion criteria (evidence of any neurologic or other medical disorder that could produce cognitive deterioration) for the total study population, for both sexes, and for four age groups (60 to 64, 65 to 69, 70 to 74, and 75 to 78 years). Subjective memory impairment was present in 76.3% of the subjects. Prevalence rates for objective memory impairment ranged from 31.9 to 78.4% in individual tests. A total of 564 subjects (239 men, 325 women) were classified as having AAMI by the inclusion criteria alone, giving a prevalence rate of 53.8% (men, 57.4%; women, 51.3%). When we included the exclusion criteria, the prevalence of AAMI decreased to 38.4% (men, 42.5%; women, 35.7%). By both methods, age- and sex-specific prevalence rates were highest in the youngest group, aged 60 to 64 years, and lowest in the oldest group, aged 75 to 78 years. We conclude that the prevalence of AAMI, by the diagnostic criteria of the NIMH Work Group, is high in the elderly Finnish population.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1994

Association of apolipoprotein E phenotypes with late onset Alzheimer's disease: population based study.

OBJECTIVE: To determine the association between the e4 allele of apolipoprotein E and Alzheimer's disease in a randomly selected population sample. DESIGN: Cross sectional population based study. SUBJECTS: 980 people aged 69 to 78 (349 men, 631 women). SETTING: Population of Kuopio, eastern Finland. MAIN OUTCOME MEASURES: Presence of e4 allele and diagnosis of Alzheimer's disease by detailed neurological and neurophysiological evaluation. RESULTS: 46 (4.7%) subjects were classified as having probable or possible Alzheimer's disease. The frequency of the apolipoprotein E e4 allele was 0.359 in patients with Alzheimer's disease and 0.165 subjects without dementia (P < 0.0001). The prevalence of Alzheimer's disease was 2.9% in subjects with no e4 alleles, 7.6% in subjects with one e4 allele, and 21.4% in subjects with two e4 alleles of apolipoprotein E. CONCLUSIONS: Allele e4 of apolipoprotein is associated with Alzheimer's disease in a dose-response fashion in a randomly selected elderly population.

Aged↗
PubMed1994

Subjective memory complaints and personality traits in normal elderly subjects.

OBJECTIVE: To evaluate the relationship between objectively measured memory functions and subjective complaints of memory disturbance and whether subjective complaints are affected by some personality traits or affective states. DESIGN: Cross-sectional two-group comparison. SETTING: The city of Kuopio in Eastern Finland, considered representative of the urban elderly population of Finland. PARTICIPANTS: Originally 403 subjects aged 67-78 years from the random sample and then two matched study groups initially including eighteen subjects but only ten in the final analysis. MEASUREMENTS: Screening and follow-up examinations of subjects with and without subjective memory complaints: (1) Memory functions: Benton's visual retention test and the paired-associated learning subtest of Wechsler Memory Scale. (2) Memory complaints: Memory Complaint Questionnaire. (3) Personality traits and affective state: Two subscales from Minnesota Multiphasic Personality Inventory and Geriatric Depression Scale. RESULTS: Complaints of memory loss did not correlate with the actual memory performance in the tests. However, those subjects who most emphatically complained of memory disturbance had greater tendencies toward somatic complaining, higher feelings of anxiety about their physical health, and more negative feelings of their own competence and capabilities than those who did not complain of memory deterioration associated with aging. CONCLUSIONS: The study suggests that subjective feelings of memory impairment are more closely associated with personality traits than with actual memory performance in normal elderly people.

Affect↗
PubMed1994

Volumetric MRI analysis of the amygdala and the hippocampus in subjects with age-associated memory impairment: correlation to visual and verbal memory.

Age-associated memory impairment (AAMI) is a common but disputed entity. It is unclear whether AAMI is a phenomenon of normal aging or an early sign of Alzheimer's disease. The present study aimed to identify possible structural abnormalities in the medial temporal lobe of AAMI subjects. We measured volumes of the hippocampus and amygdala by MRI in 16 AAMI subjects and in 16 age- and sex-matched controls and correlated the volumes with subjects' performance on two visual memory tasks (the Benton and the Heaton visual retention tests) and on a verbal memory task (the Buschke-Fuld Selective Reminding Test). The mean hippocampal and amygdaloid volumes normalized for brain size per se did not differ between the two study groups. In controls, but not in AAMI subjects, the right hippocampus was larger than the left. Accordingly, the volumetric asymmetry between the right and left hippocampi was smaller in AAMI subjects than in controls (Student's t test, p < 0.05). The volume of the right hippocampus (r = 0.37, n = 32, p < 0.05) and the magnitude of the asymmetry between the right and left hippocampi (r = 0.38, n = 32, p < 0.05) correlated with total score on the Benton test. We also found significant correlations between the amygdaloid volumes and the performance on visual memory tests but not with score on the verbal memory test.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Carotid stenosis by digital subtraction angiography: reproducibility of the European Carotid Surgery Trial and the North American Symptomatic Carotid Endarterectomy Trial measurement methods and visual interpretation.

PURPOSE: To evaluate different carotid stenosis estimation methods with digital subtraction angiography. METHODS: We assessed the intraobserver reproducibilty and interobserver variability of visual interpretation and the measurement methods used by the European Carotid Surgery Trial and the North American Symptomatic Carotid Endarterectomy Trial. Angiographic stenosis measurements according to both criteria were performed twice by a radiologist, a neurologist, and a vascular surgeon. Eighty bifurcations of consecutive symptomatic patients underwent 480 pairs of measurements. In addition, four radiologists estimated the stenoses visually. RESULTS: Intraobserver consistency was slightly better by the European (kappa, 0.86 to 0.94) than by the North American (kappa, 0.68 to 0.91) trial criteria or by visual interpretation (kappa, 0.79 to 0.81). No significant interobserver variability was found, except in the subgroup of mild stenoses by the North American Trial criteria. By kappa statistic, the interobserver agreement was excellent by the European trial method (kappa, 0.72 to 0.86), good by the North American trial method (kappa, 0.59 to 0.77), and good to excellent by visual evaluation (kappa, 0.68 to 0.88). The visual estimation agreed more closely with the European (kappa, 0.73 to 0.92) than with the North American trial (kappa, 0.55 to 0.74) criteria measurements. CONCLUSIONS: All three methods have good reproducibility in digital subtraction angiography. Interobserver differences become more important in the estimation of mild stenosis.

Adult↗
PubMed1993

Circulating immune complexes in sera from patients with Alzheimer's disease and subjects with age-associated memory impairment.

Before, we reported a higher frequency of circulating immune complexes (CIC) in the sera from institutionalized Alzheimer's disease (AD), multi-infarct dementia and Down's syndrome patients than from age-matched controls. In this study, we tested the presence of CIC in the sera from an extended series of hospitalized AD patients, AD patients living in the community, from age-associated memory impairment (AAMI) subjects as well as from nursing home and community controls. We used two methods to measure CIC, C1q binding Elisa (C1qB-Elisa) and conglutinin binding (KgB-Elisa). The AD patients showed the highest frequency of positive findings and differed from the controls in KgB (42% vs. 17%) (Chi-square, p = 0.01) and C1qB (30% vs. 11%) (p < 0.05). In severe AD, 14/19 patients were KgB positive and 11/19 were C1qB positive and differed from controls. The frequency of CIC for the patients with moderate or mild dementia, the AAMI subjects and controls was similar. In the multivariate linear regression analysis, high CIC values of the AD patients significantly associated with a long disease duration and a history of recurrent urinary infections but not with age, sex, hospitalization, or the Mini-Mental Status score. We conclude that AD patients with severe dementia frequently show CIC but those with mild or moderate disease do not. The CIC relate to a long disease duration and a history of recurrent urinary infections.

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PubMed1993

Essential hypertension and cognitive function. The role of hyperinsulinemia.

The relation between hypertension and cognitive function is not well established. Therefore, we examined cognitive function in a random sample of 744 nondiabetic elderly inhabitants of Kuopio, East Finland. Five brief neuropsychological tests known to be sensitive to cognitive impairment due to dementia--the Mini-Mental State Examination (MMSE), the Trail Making Test (TMT), the Buschke Selective Reminding Test (BSR), Russell's Adaptation of the Visual Reproduction Test (HVR), and the Verbal Fluency Test (VFT)--were used to evaluate cognitive function. The performance of the hypertensive group (n = 378) was impaired in almost all test items compared with that of the normotensive group (n = 366), but the difference between these two groups was statistically significant in 5 of 19 test items only. Moreover, within the hypertensive group, hyperinsulinemic (fasting plasma insulin > 17.9 mU/L) hypertensive subjects (n = 57) scored worse than normoinsulinemic hypertensive subjects (n = 321) in 16 of 19 test items and worse than the normotensive subjects in the same 16 of 19 test items. The difference between the hyperinsulinemic hypertensive and normotensive groups was significant in 11 test items that reflected complex cognitive function such as calculation, language, semantic memory, and problem solving. This difference in neuropsychological tests among the three study groups (normotensive, normoinsulinemic hypertensive, and hyperinsulinemic hypertensive subjects) persisted after adjustment for fasting plasma glucose, age, sex, and education in 3 test items measuring calculation, copying, and semantic memory. Thus, essential hypertension in the elderly is associated with an impairment in complex cognitive function.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1991

Electroneuromyographic findings in patients with Alzheimer's disease.

Electroneurophysiological abnormalities have been reported in some patients with dementia, but the data available is rather limited and controversial. We studied nerve conduction velocities and electromyography in 59 patients with moderate to severe involvement of Alzheimer's disease. Except some occasional mono- and polyneuropathies, the patients showed no systemic dysfunction of the peripheral nervous system.

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