Kim M. Kiely

Cognitive, Health, and Sociodemographic Predictors of Longitudinal Decline in Hearing Acuity Among Older Adults

BACKGROUND We aimed to investigate predictors of change in pure-tone hearing thresholds in older adults. METHODS Data were drawn from a pooled sample from the Dynamic Analyses to Optimise Ageing (DYNOPTA) project (N = 4,221, mean age = 73.6, range: 50-103 years). Pure-tone hearing thresholds were tested for frequencies between 0.5 and 8 kHz, on up to four occasions over a period of 11 years. Linear mixed models tested for predictors of change in hearing. RESULTS Hearing loss for high-range frequencies preceded decline in low-range frequencies. Men had higher baseline hearing thresholds, but women experienced faster rates of decline in hearing for mid- to high-range frequencies. The estimated rate of change for a 75-year-old adult was 0.91 decibel hearing level (dB HL) per year for pure-tone thresholds averaged over frequencies ranging between 0.5 and 4 kHz in the better ear. Baseline age (β = 0.03, p < .01), hypertension (β = 0.15, p < .01), and probable cognitive impairment (β = 0.40, p = .01) were independent predictors of annual rate of change in hearing thresholds. Incidence of probable cognitive impairment was also associated with higher hearing thresholds. Other known correlates for prevalence of hearing impairment, including low education, noise damage, diabetes, and history of stroke were independently associated with baseline levels of hearing but were not predictive of change in hearing thresholds. CONCLUSIONS Faster rates of decline in hearing are predicted by probable cognitive impairment and hypertension.

Cohort profile: The Dynamic Analyses to Optimize Ageing (DYNOPTA) project

National Health and Medical Research Council (410215); NHMRC Fellowships (#366756 to K.J.A. and #316970 to P.B.)

Dual Sensory Loss and Depressive Symptoms: The Importance of Hearing, Daily Functioning, and Activity Engagement

Background: The association between dual sensory loss (DSL) and mental health has been well established. However, most studies have relied on self-report data and lacked measures that would enable researchers to examine causal pathways between DSL and depression. This study seeks to extend this research by examining the effects of DSL on mental health, and identify factors that explain the longitudinal associations between sensory loss and depressive symptoms. Methods: Piecewise linear-mixed models were used to analyze 16-years of longitudinal data collected on up to five occasions from 1611 adults (51% men) aged between 65 and 103 years. Depressive symptoms were assessed by the Centre for Epidemiological Studies Depression (CES-D). Vision loss (VL) was defined by corrected visual acuity >0.3 logMAR in the better eye, blindness, or glaucoma. Hearing loss (HL) was defined by pure-tone average (PTA) >25 dB in the better hearing ear. Analyses were adjusted for socio-demographics, medical conditions, lifestyle behaviors, activities of daily living (ADLs), cognitive function, and social engagement. Results: Unadjusted models indicated that higher levels of depressive symptoms were associated with HL (B = 1.16, SE = 0.33) and DSL (B = 2.15, SE = 0.39) but not VL. Greater rates of change in depressive symptoms were also evident after the onset of HL (B = 0.16, SE = 0.06, p < 0.01) and DSL (B = 0.30, SE = 0.09, p < 0.01). The associations between depressive symptoms and sensory loss were explained by difficulties with ADLs, and social engagement. Conclusion: Vision and HL are highly prevalent among older adults and their co-occurrence may compound their respective impacts on health, functioning, and activity engagement, thereby exerting strong effects on the mental health and wellbeing of those affected. There is therefore a need for rehabilitation programs to be sensitive to the combined effects of sensory loss on individuals.

Estimates of probable dementia prevalence from population-based surveys compared with dementia prevalence estimates based on meta-analyses

BackgroundNational data on dementia prevalence are not always available, yet it may be possible to obtain estimates from large surveys that include dementia screening instruments. In Australia, many of the dementia prevalence estimates are based on European data collected between 15 and 50 years ago. We derived population-based estimates of probable dementia and possible cognitive impairment in Australian studies using the Mini-Mental State Examination (MMSE), and compared these to estimates of dementia prevalence from meta-analyses of European studies.MethodsData sources included a pooled dataset of Australian longitudinal studies (DYNOPTA), and two Australian Bureau of Statistics National Surveys of Mental Health and Wellbeing. National rates of probable dementia (MMSE < 24) and possible cognitive impairment (24-26) were estimated using combined sample weights.ResultsEstimates of probable dementia were higher in surveys than in meta-analyses for ages 65-84, but were similar at ages 85 and older. Surveys used weights to account for sample bias, but no adjustments were made in meta-analyses. Results from DYNOPTA and meta-analyses had a very similar pattern of increase with age. Contrary to trends from some meta-analyses, rates of probable dementia were not higher among women in the Australian surveys. Lower education was associated with higher prevalence of probable dementia. Data from investigator-led longitudinal studies designed to assess cognitive decline appeared more reliable than government health surveys.ConclusionsThis study shows that estimates of probable dementia based on MMSE in studies where cognitive decline and dementia are a focus, are a useful adjunct to clinical studies of dementia prevalence. Such information and may be used to inform projections of dementia prevalence and the concomitant burden of disease.

Older Drivers in Australia: Trends in Driving Status and Cognitive and Visual Impairment

OBJECTIVES: To investigate self‐reported driving status within three Australian states; associations between demographic, health, and functional factors and driving status; and the extent to which remaining a driver in spite of cognitive and visual impairments varies as a function of sex.

Evaluating a dichotomized measure of self- reported hearing loss against gold standard audiometry: prevalence estimates and age bias in a pooled national data set

Objectives: To evaluate a harmonized binary measure of self-reported hearing loss against gold standard audiometry in an older adult population. Method: Seven nationally representative population-based studies were harmonized and pooled (n = 23,001). Self-report items were recoded into a dichotomous format. Audiometric hearing loss was defined by averaged pure-tone thresholds greater than 25-decibel hearing level in the better ear. We compared age and sex stratified prevalence rates of hearing loss estimated by self-report and audiometric measures. Results: Overall, 56% of men and 43% of women had audiometric hearing loss. There were moderate associations between self-reported and audiometric hearing loss. However, prevalence based on self-report was overestimated for adults aged below 70 years and underestimated for adults aged above 75. Discussion: Self-report of hearing loss is insensitive to age effects and does not provide a reliable basis for estimating prevalence of age-related hearing loss, although may indicate perceived hearing disability.

Depressive symptoms predict decline in perceptual speed in older adulthood.

Depressive symptoms and cognitive decline are associated in older age, but research is inconsistent about whether one condition influences the development of the other. We examined the directionality of relations between depressive symptoms and perceptual speed using bivariate dual change score models. Assessments of depressive symptoms and perceptual speed were completed by 1,206 nondemented older adults at baseline, and after 2, 8, 11, and 15 years. After controlling for age, education, baseline general cognitive ability, and self-reported health, allowing depressive symptoms to predict subsequent change in perceptual speed provided the best fit. More depressive symptoms predicted subsequently stronger declines in perceptual speed over time lags of 1 year.

Validation of four measures of mental health against depression and generalized anxiety in a community based sample.

There is a need to validate screening measures of affective and generalized anxiety disorders for use in epidemiological surveys of mental health in the general population. This study examined the diagnostic accuracy of the Patient Health Questionnaire (PHQ-9), Goldberg Anxiety and Depression Scales (GAS, GDS) and the 12-item Short Form Health Survey (SF-12) Mental Health Component Summary Scale (MCS-12) in a population based longitudinal study in Australia. We report analyses of two narrow age birth cohorts in the Personality and Total Health (PATH) through life study (ages 32-36 and 52-58). Depressive episodes (severe, moderate, and mild), dysthymia and generalized anxiety disorder were diagnosed according to International Classification of Diseases (ICD-10) criteria using the World Health Organisation (WHO) Composite International Diagnostic Interview (CIDI) as a criterion. All scales had high concordance with their target 30-day diagnoses, with area under the Receiver Operating Characteristic (ROC) curve (AUC) ranging between 0.85 and 0.90. The PHQ-9, GDS, GAS and MCS-12 were all valid instruments for identifying possible cases of depression and anxiety, and assessing the severity of these common mental disorders in the general population. We report recommended cut-points for each scale, though note that the optimal cut-point on mental health screening instruments may vary depending on the context of test administration.

Multiple imputation was an efficient method for harmonizing the Mini-Mental State Examination with missing item-level data

OBJECTIVE The Mini-Mental State Examination (MMSE) is used to estimate current cognitive status and as a screen for possible dementia. Missing item-level data are commonly reported. Attention to missing data is particularly important. However, there are concerns that common procedures for dealing with missing data, for example, listwise deletion and mean item substitution, are inadequate. STUDY DESIGN AND SETTING We used multiple imputation (MI) to estimate missing MMSE data in 17,303 participants who were drawn from the Dynamic Analyses to Optimize Aging project, a harmonization project of nine Australian longitudinal studies of aging. RESULTS Our results indicated differences in mean MMSE scores between those participants with and without missing data, a pattern consistent over age and gender levels. MI inflated MMSE scores, but differences between those imputed and those without missing data still existed. A simulation model supported the efficacy of MI to estimate missing item level, although serious decrements in estimation occurred when 50% or more of item-level data were missing, particularly for the oldest participants. CONCLUSIONS Our adaptation of MI to obtain a probable estimate for missing MMSE item level data provides a suitable method when the proportion of missing item-level data is not excessive.

The Symbol Digit Modalities Test:: Normative Data from a Large Nationally Representative Sample of Australians

Data from the Household, Income and Labour Dynamics in Australia (HILDA) Survey were used to calculate weighted norms for the written version of the Symbol Digits Modalities Test (SDMT) by gender, 5-year age groups and four levels of educational attainment. The sample comprised 14,456 Australians (47% male; age range 15-100), of whom 25% reported a tertiary qualification, 30% reported a technical qualification (diploma or trade certificate), 16% reported completing Year 12 (final year of high school), and 29% reported their highest level of educational attainment to be Year 11 or below. Participants were excluded if they reported physical or neurological conditions that limited performance. Age, gender, and education were all significantly associated with SDMT performance, as was poor health, and cultural background. The reported norms are of greater scope and precision than previously available and have utility in a range of clinical and research settings. Indeed, normative data for the SDMT that are representative of a national population have not previously been published.