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Biomedical subjects

A J Mackinnon

Publications and source records attributed to A J Mackinnon.

At least 19 recordsLinked to original sources
PubMed1997

Accurate confidence intervals for measures of test performance.

The use of confidence intervals to estimate population parameters is briefly reviewed. Exact binomial confidence intervals can be calculated through the use of tables or statistical software packages. As an alternative, a microcomputer program to calculate sensitivity and specificity, point estimates and binomial confidence intervals for false-negative and -positive rate, positive and negative predictive power, prevalence of cases and non-cases, correct classification rate, and misclassification rate has also been developed. Characteristics of the computer program, 'AccuCon', which is available from the authors, are described.

Confidence Intervals↗
PubMed1997

The psychogeriatric assessment scales (PAS): further data on psychometric properties and validity from a longitudinal study of the elderly.

The PAS is a standardized interview which assesses the changes seen in dementia and depression using a set of scales. There are three scales derived from an interview with the subject (cognitive impairment, depression, stroke) and three from an interview with an informant (cognitive decline, behaviour change, stroke). The aim was to provide data on the psychometric properties and validity of the PAS. The scales were originally developed using data from the first wave of a longitudinal study of the elderly. Reported here are further data on the PAS from the second wave of the same study, carried out 3 1/2 years later. The setting was a community survey carried out in the Australian city of Canberra. Seven hundred and nine elderly persons, with a mean age of 80 years, and 641 informants participated. Besides the PAS, participants were administered several other scales: the Mini-Mental State Examination, the Informant Questionnaire on Cognitive Decline in the Elderly, the National Adult Reading Test and the Goldberg anxiety and depression scales. Diagnoses of dementia and depression were made with the Canberra Interview for the Elderly, from which the PAS is derived. Confirmatory factor analysis replicated the five-factor model which underpins the PAS. The PAS was found to correlate with the other scales having similar content and showed correspondence with diagnoses of dementia and depression derived from the Canberra Interview for the Elderly. Longitudinal data supported the validity of the cognitive decline scale as a measure of change. Overall, the results support the original psychometric and validity research on the PAS.

Aged↗
PubMed1997

Education and decline in cognitive performance: compensatory but not protective.

The association between education and cognitive change was investigated in a large community sample of elderly people followed up after 3.6 years. Lower education was predictive of decline on the Mini-Mental State Examination (MMSE) and on tests of language and knowledge, but not on tests of cognitive speed, memory or reaction time. The effects of education were not attenuated when adjusted for health, disability or activity level. The findings suggest that education slows the rate of decline on crystallized intelligence, but not other cognitive abilities. Education may compensate for neurodegenerative changes rather than protect against them.

Activities of Daily Living↗
PubMed1997

ICD-10 mild cognitive disorder: its outcome three years later.

OBJECTIVE: The aims were to (i) report the outcome of mild cognitive disorder (MCD) 3.6 years after initial interview and diagnosis; (ii) identify predictors of new cases of MCD. The hypotheses were that (i) persons with MCD are more likely to develop dementia than those without MCD; (ii) symptoms of anxiety or depression predict MCD caseness at follow-up. DESIGN: Longitudinal cohort study. SETTING: Community of elderly people (age 70-97 years). PARTICIPANTS: 612 of 897 elderly subjects (mean 76 years) were reinterviewed. Of the 36 MCD cases originally identified, 25 were available at follow-up. 24 incident cases of MCD were identified. MAIN OUTCOME MEASURES: ICD-10 dementia, DSM-III-R dementia, ICD-10 mild cognitive disorder diagnoses made by the Canberra Interview for the Elderly, tests of anxiety, depression, neuroticism and cognitive performance. MAIN RESULTS: Of the original 25 MCD cases available at follow-up, two had a diagnosis of MCD, and three had a diagnosis of both ICD-10 and DSM-III-R dementia. The prevalence of MCD and DSM-III-R dementia at follow-up was no greater for MCD cases diagnosed at initial interview than in normal subjects at initial interview. There was, however, an increased prevalence of ICD-10 dementia among original MCD cases. At initial interview and at follow-up MCD cases were more anxious and depressed but had similar cognitive performance to normals. For incident cases of MCD the only significant predictor was age. CONCLUSIONS: MCD cannot be seen to be a specific forerunner of dementia. Those with a diagnosis of MCD are distinguished more by their anxiety, depression and neuroticism than by their cognitive deficits.

Aged↗
PubMed1997

The course of depression in the elderly: a longitudinal community-based study in Australia.

BACKGROUND: We report the outcome of depressive states after 3-4 years in a community sample of the elderly. METHODS: A sample of 1045 persons aged 70+ years in 1990-1 was re-interviewed after 3.6 years. RESULTS: Mortality (21.7%) and refusal or non-availability (10.4%) were higher in those who initially had had a diagnosis or symptoms of depression. Of those with an ICD-10 depressive episode in 1990-1, 13% retained that diagnosis. Of those who were not depressed initially only 2.5% had become cases. Depression was unrelated to age or apolipoprotein E genotype. The best predictors of the number of depressive symptoms at follow-up was the number at Wave 1, followed by deterioration in health and in activities of daily living, high neuroticism, poor current health, poor social support, low current activity levels and high service use. Depressive symptoms at Wave 1 did not predict subsequent cognitive decline or dementia. CONCLUSIONS: Non-random sample attrition is unavoidable. ICD-10 criteria yield more cases than other systems, while continuous measures of symptoms confer analytical advantages. Risk factors for depressive states in the elderly have been further identified. The prognosis for these states is favourable. At the community level, depressive symptoms do not seem to predict cognitive decline, as they do in referred series.

Activities of Daily Living↗
PubMed1997

A prospective study of cognitive function in the elderly.

BACKGROUND: We report on the change in cognitive function in a population sample of elderly people who have been examined on two occasions more than 3 years apart. METHODS: A sample of 1135 persons aged 70-102 years was interviewed at base-line then re-interviewed 3.6 years later with the Canberra Interview for the Elderly, which included tests of episodic memory and cognitive speed as well as the Mini-Mental State Examination and the National Adult Reading Test (NART). RESULTS: Mortality and loss to follow-up reduced the sample to 736, of whom 614 completed at least one test of cognitive performance on both occasions. Cognitive performance decreased with age, except on the NART. Decline over the follow-up period increased as a function of age in all cognitive measures, except the NART. Change in cognitive scores was close to normal distribution. Incident dementia was associated strongly with age and current level of cognitive performance, but not with rate of decline. Cognitive decline and the risk of incident dementia did not differ by gender. CONCLUSIONS: A score indicating possible impairment in the very elderly carries a worse prognosis than for the younger elderly. Decline is almost universal in at least one cognitive area among those over the age of 85.

Aged↗
PubMed1996

Activity levels and cognitive functioning in an elderly community sample.

The influence of self-reported and informant-reported activity levels on Crystallized Intelligence, Fluid Intelligence, Memory and the Mini-Mental State Examination was investigated in a sample of 858 community-dwelling elderly subjects. Both self-reported and informant-reported activity levels explained variance beyond that accounted for by sex, sensory functioning, activities of daily living, medical conditions, current health problems and education. Age accounted for additional variance once activity and the other contextual variables were entered. Interaction effects indicated that inactivity was associated with poorer performance on fluid intelligence in older rather than younger elderly subjects and that inactivity was predictive of poor crystallized intelligence at younger ages. Higher informant-rated activity levels moderated the effects of education, so that higher activity offset effects associated with low education on memory tasks. The mount of variance explained by activity levels was modest.

Activities of Daily Living↗
PubMed1995

Apolipoprotein E allele epsilon 4, dementia, and cognitive decline in a population sample.

From clinically based series it has been proposed that, in homozygotes for the apolipoprotein E epsilon 4 (apoE epsilon 4) allele, Alzheimer's disease is almost inevitable by the age of 80. A population sample of persons aged 70 years and over was interviewed in 1990-91 to ascertain the presence of dementia or cognitive impairment. The sample was reinterviewed in 1994, when the apoE genotype was also determined. Prevalence data for the 638 persons who completed the second examination revealed a linear association between having an apoE epsilon 4 allele and both dementia and cognitive impairment (for heterozygotes, odds ratio for dementia 1.89, 95% confidence interval 1.04-3.44 and for homozygotes OR 3.58, 95% CI 1.08-11.82; both adjusted for age). However, even in subjects homozygous for epsilon 4 the estimated prevalence of dementia by age 90 was only about 50%. Persons with one or two epsilon 4 alleles were more likely to have a family history of dementia than those with none. This study confirms in a population sample that the epsilon 4 allele is a risk factor for dementia, but refutes the suggestion that homozygosity for the epsilon 4 allele is sufficient for the development of Alzheimer's disease: persons with either one or two epsilon 4 alleles may reach late old age without cognitive impairment.

Aged↗
PubMed1995

Insomnia in the elderly: its prevalence and correlates in the general population.

OBJECTIVE: To estimate the prevalence of persistent insomnia and its correlates in samples of people living in the community and in institutional settings. METHODS: Respondents were interviewed in their place of residence by trained interviewers using the Canberra Interview for the Elderly, a structured psychiatric examination. RESULTS: Information about sleeping habits was obtained from 874 community and 59 institutional residents. Insomnia was persistent in 16% of the community-dwelling population and 12% of the institutional residents, with 15% and 40%, respectively, regularly taking a hypnotic. Of those without insomnia, 10% in the community but over a third in institutions were using a hypnotic. Insomnia was associated with depression, pain and poor physical health. CONCLUSIONS: Persistent insomnia in the elderly, as in other age groups, is strongly associated with depressed mood, as well as with physical disease. Because of this, insomnia should not be dismissed as a normal part of ageing, and therefore ignored as a significant symptom. Continued surveillance is needed in general practice, geriatric services and nursing homes of the routine use of hypnotics by the elderly.

Activities of Daily Living↗
PubMed1995

ICD-10 mild cognitive disorder: epidemiological evidence on its validity.

Criteria for the diagnosis of ICD-10 Mild Cognitive Disorder (MCD) were applied to a sample of 897 community dwelling elderly participants. Criterion A (the presence of a physical disorder) was met by 44%, Criterion B (report of a cognitive disorder) by 17%, Criterion C (an abnormality in quantified cognitive assessments) by 60%, and Criterion D (exclusion on basis of dementia and other conditions) by 74%. A total of 36 cases (4%) met all four criteria. Correlations between Criteria A and B, and B and C were weak (r = 0.18), and the correlation between Criteria A and C was almost zero (r = 0.02). This suggests that no syndrome exists. Membership of MCD was predicted by a report that memory or intelligence interfered with daily life but not by performance on cognitive tests or by a report of physical illness. Cases of MCD had higher anxiety, depression and neuroticism scores than normal elderly, but did not differ substantially on tests of cognitive functioning. These findings call into question the validity of the ICD-10 diagnosis of MCD.

Activities of Daily Living↗
PubMed1995

The Psychogeriatric Assessment Scales: a multi-dimensional alternative to categorical diagnoses of dementia and depression in the elderly.

The Psychogeriatric Assessment Scales (PAS) provide an assessment of the clinical changes seen in dementia and depression. Principal components analysis and latent trait analysis were used to develop a set of scales to summarize these clinical changes. There are three scales derived from an interview with the subject (Cognitive Impairment, Depression, Stroke) and three from an interview with an informant (Cognitive Decline, Behaviour Change, Stroke). Results are reported on the reliability and validity of these scales using data from clinical samples in Sydney and Geneva and a population sample from Canberra. The scales were found to have excellent validity when judged against clinical diagnoses of dementia and depression and could distinguish Alzheimer's from vascular dementia. Cut-off points were developed to indicate correspondence between scale scores and clinical diagnoses. Percentile rank norms were developed from the Canberra population sample. The PAS is easy to administer and score and can be used by lay interviewers after training. It is intended for application both in research and in services for the elderly.

Activities of Daily Living↗
PubMed1995

Factors associated with the wish to die in elderly people.

This study aimed to determine the prevalence of the wish to die in elderly people and investigate the factors associated with it, in particular, whether factors other than depression contribute to the wish to die. Data were obtained from an Australian epidemiological survey of people aged 70 or more. Survey participants were asked whether, in the last two weeks, they had felt that they wanted to die and, if so, if they had had such thoughts repeatedly. Three classes of possible risk factors were investigated: sociodemographic factors (age, sex, marital status), mental health (depression, cognitive impairment), and physical health (poor self-rated health, disability, pain, sensory impairment, and living in a nursing home or hostel). Only 21 of 923 elderly persons reported repeatedly having had a wish to die during the previous two weeks. Although the wish to die was associated with depression, there were several other factors also associated with it independently of depression: not being married, poor self-rated health, disability, pain, hearing impairment, visual impairment, living in a nursing home or hostel. A small minority expressed the wish to die but had a normal mood state. It was concluded that the wish to die is associated with several factors in addition to depression and may be present in individuals with few depressive symptoms. There is a need to investigate whether factors associated with the wish to die are treatable and whether this can restore the desire to live.

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PubMed1994

Do mental health surveys disturb? Further evidence.

In a community survey of 873 persons aged 70 years or over, focusing on dementia, cognitive decline, depression, and current life circumstances, we included an enquiry into the emotional impact of the interview. A large majority reported at the end of the interview that it had no adverse effect on their emotional state. About 4% reported that it made them distressed, 1% that it depressed them, and 2% that it had intruded on their privacy. By contrast, 52% said it had made them feel good about themselves. Distress seemed to be largely related to performing poorly on cognitive tests. There is no information on the duration of these effects in the period following the interview. It is recommended that respondents in community surveys, including the elderly, be informed that they can decline to answer any question, and that interviewers be trained in how to respond to the few who will be distressed by the experience.

Aged↗
PubMed1994

Complaints of cognitive decline in the elderly: a comparison of reports by subjects and informants in a community survey.

In a community survey, subjects and their informants were asked the same questions about memory and intellectual decline in the subjects. Subjects and informants both commonly reported cognitive decline, although in most cases the decline was not seen as interfering with daily life. However, when responses from subjects and informants were cross-tabulated, agreement was found to be poor. For subjects, reports of cognitive decline were correlated with anxiety and depression symptoms and with trait neuroticism. Subjects' reports were uncorrelated with age and only weakly correlated with cognitive test performance, indicating little validity. By contrast, informants' reports were correlated with the subjects' cognitive test performance and age, but also with the informants' own anxiety and depression symptoms. Although informants' reports have validity, they may also be contaminated by the informants' affective state.

Aged↗
PubMed1994

The relationship between health and cognitive functioning in a sample of elderly people in the community.

The association between health status and cognitive performance was examined in a sample of 708 community dwelling elderly people aged 70 years or over. Cognitive performance declined significantly across the age groups 70-74, 75-79, 80-84, and 85-89 years on the Mini-Mental State Examination and on measures of fluid intelligence and memory, but not on measures of crystallized intelligence. Health status declined significantly across age for five of 49 past and current medical conditions, for measures of Activities of Daily Living (ADL) and for systolic blood pressure, but did not decline significantly for global self-ratings of health, diastolic blood pressure or reports of smoking. Weak but significant correlations between health and cognitive performance were found for self-reported global ratings of health and for self-reports of some physical symptoms but not for diastolic or systolic blood pressure, or for many other physical conditions. Both self- and informant-based ratings of ADL correlated with cognitive performance. Age differences remained after cognitive performance was adjusted for health variables such as ADL, self-ratings of health and current health problems. It is concluded that, at the population level, lower levels of cognitive performance in community-dwelling elderly subjects are not strongly mediated by ill health.

Activities of Daily Living↗
PubMed1993

The disabled elderly living in the community: care received from family and formal services.

OBJECTIVES: Based on a community sample, to assess the reasons disabled elderly people need care, the type of formal services they receive, the characteristics of their carers and the degree of psychological morbidity in these carers. DESIGN AND SETTING: A community survey of people aged 70 or more years living in Canberra or Queanbeyan. Survey participants were asked to nominate informants, who were interviewed about the subjects' state of health. The informants provided information on need for care, services received and the role of carers. Informants also reported on their own health, including symptoms of anxiety and depression. RESULTS: Elderly people needed care because of physical disability more often than behavioural disability. Those with physical disability received more formal services and more help from health professionals than those with behavioural disability. Contact with general practitioners was high for both disabled and non-disabled subjects. Carers of the physically disabled had raised levels of anxiety and symptoms of depression, and poorer self-rated health, but carers of the behaviourally disabled did not. Wives, daughters and husbands made up the biggest categories of carers and around two-thirds of carers were women. CONCLUSION: Family carers play an important role in maintaining disabled elderly people in the community and this role is often stressful. Formal services have to be aimed as much at the needs of the carers as at the disabled people themselves.

Activities of Daily Living↗
PubMed1992

An epidemiological study of mental health and socioeconomic conditions in Sumatera, Indonesia.

A mental health survey was conducted in Palembang, Indonesia, to test the hypothesis that rapid socioeconomic and cultural change is detrimental to mental health. The 30-item General Health Questionnaire, translated into Bahasa Indonesia, was administered to a probability sample of 1670 adults (94.9% of the target sample). The Present State Examination was conducted on a weighted subsample of 100, using a 2-phase design. Overall morbidity rates were surprisingly similar to those in industrialized countries. A strong association was found between psychological symptoms and poverty. Persons belonging to communities that had progressed substantially in standards of living had fewer symptoms. The evidence points to a possibly beneficial effect of economic progress on mental health. Longitudinal data are needed to confirm this.

Adolescent↗