Ciaran Finucane

Correlation of accelerometry with clinical balance tests in older fallers and non-fallers

BACKGROUND falls are a common cause of injury and decreased functional independence in the older adult. Diagnosis and treatment of fallers require tools that accurately assess physiological parameters associated with balance. Validated clinical tools include the Berg Balance Scale (BBS) and the Timed Up and Go test (TUG); however, the BBS tends to be subjective in nature, while the TUG quantifies an individuals functional impairment but requires further subjective evaluation for balance assessment. Other quantitative alternatives to date require expensive, sophisticated equipment. Measurement of the acceleration of centre of mass, with relatively inexpensive, lightweight, body-mounted accelerometers is a potential solution to this problem. OBJECTIVES to determine (i) if accelerometry correlates with standard clinical tests (BBS and TUG), (ii) to characterise accelerometer responses to increasingly difficult challenges to balance and (iii) to characterise acceleration patterns between fallers and non-fallers. STUDY DESIGN AND SETTING torso accelerations were measured at the level of L3 using a tri-axial accelerometer under four conditions; standing unsupported with eyes open (EO), eyes closed (EC) and on a mat with eyes open (MAT EO) and closed (MAT EC). Older patients (n = 21, 8 males, 13 females) with a mean age of 78 (SD +/- 7.6) years who attended a day hospital were recruited for this study. Patients were identified as fallers or non-fallers based on a comprehensive falls history. MEASUREMENTS Spearmans rank correlation analysis examined the relationship between acceleration root mean square (RMS) data and the BBS while Pearsons correlation was used with TUG scores. Differences in accelerometer RMS between fallers and non-fallers and between test conditions were examined using t-test and non-parametric alternatives where appropriate. RESULTS there was a stepwise increase in accelerometer RMS with increasing task complexity, and the accelerometer was able to distinguish significantly between sway responses to all test conditions except between EO and EC (P < 0.05). Acceleration data for MAT EO were significantly and inversely correlated with BBS scores (P = -0.829, P < 0.001) and positively correlated with TUG values (r = 0.621, P < 0.01). There was a significant difference in acceleration RMS for MAT EO between fallers and non-fallers (P < 0.011). CONCLUSIONS this is the first study of its kind to show a high correlation between accelerometry, the BBS and TUG. Accelerometry could also distinguish between sway responses to differing balancing conditions and between fallers and non-fallers. Accelerometry was shown to be an efficient, quantitative alternative in the measurement of balance in older people.

Low macular pigment optical density is associated with lower cognitive performance in a large, population-based sample of older adults

Macular pigment (MP) is comprised of the carotenoids lutein (L), zeaxanthin (Z), and meso-zeaxanthin (MZ), which selectively accumulate at the macula (central retina) of the eye and are neuroprotective. These carotenoids are also present in the brain, and evidence suggests a close correlation between retinal and brain concentrations. We investigated the relationship between MP and cognitive function in 4453 adults aged ≥ 50 years as part of The Irish Longitudinal Study on Aging. Macular pigment optical density (MPOD) was determined using customized heterochromatic flicker photometry-a quick and noninvasive way of measuring the concentration of the pigment. Lower MPOD was associated with poorer performance on the mini-mental state examination (p = 0.026) and on the Montreal cognitive assessment (p = 0.016). Individuals with lower MPOD also had poorer prospective memory (p = 0.011), took longer time to complete a trail-making task (p = 0.003), and had slower and more variable reaction times on a choice reaction time task (p = 0.000 and 0.001). These associations were only slightly attenuated following adjustment for physical and mental health. There was no significant association between MPOD and verbal fluency, word recall, visual reasoning, or picture memory. Overall, the findings support the theory that xanthophyll carotenoids impact on cognitive function, underscoring the need for exploration of novel, noninvasive biomarkers for cognitive vulnerability and preventive strategies.

Age-related normative changes in phasic orthostatic blood pressure in a large population study: findings from The Irish Longitudinal Study on Ageing (TILDA).

Background— In this report, we provide the first normative reference data and prevalence estimates of impaired orthostatic blood pressure (BP) stabilization, initial orthostatic hypotension, and orthostatic hypotension based on beat-to-beat blood pressure methods in a population-representative sample. Methods and Results— Participants were recruited from a nationally representative cohort study (≥50 years). Beat-to-beat systolic BP, diastolic BP, and heart rate records were analyzed among those who underwent an active stand test (n=4475). Normograms were estimated by use of generalized additive models for location, shape, and scale with Box-Cox power exponential distribution. Prevalence estimates of impaired BP stabilization, initial orthostatic hypotension, and orthostatic hypotension are reported. Orthostatic BP responses in adults aged 50 to 59 years stabilized within 30 seconds of standing, with older groups taking 30 seconds or longer. The total prevalence of impaired BP stabilization was 15.6% (95% confidence interval [CI], 14.1%–17.1%), increasing with age to 41.2% (95% CI, 30.0%–52.4%) in people ≥80 years old. Initial orthostatic hypotension occurred in 32.9% (95% CI, 31.2%–34.6%) of the population aged ≥50 years, with no age gradient evident. The prevalence of orthostatic hypotension was 6.9% (95% CI, 5.9%–7.8%) in the total population, increasing to 18.5% (95% CI, 9.0%–28.0%) in those aged ≥80 years old. Conclusions— Significant age-related differences exist in the time course of postural BP responses, with abnormal responses taking longer than 30 seconds to stabilize. Impaired BP stabilization is more common as we age, affecting more than two-fifths of the population aged ≥80 years, and may play a future role in the management of falls and syncope. # CLINICAL PERSPECTIVE {#article-title-40}Background— In this report, we provide the first normative reference data and prevalence estimates of impaired orthostatic blood pressure (BP) stabilization, initial orthostatic hypotension, and orthostatic hypotension based on beat-to-beat blood pressure methods in a population-representative sample. Methods and Results— Participants were recruited from a nationally representative cohort study (≥50 years). Beat-to-beat systolic BP, diastolic BP, and heart rate records were analyzed among those who underwent an active stand test (n=4475). Normograms were estimated by use of generalized additive models for location, shape, and scale with Box-Cox power exponential distribution. Prevalence estimates of impaired BP stabilization, initial orthostatic hypotension, and orthostatic hypotension are reported. Orthostatic BP responses in adults aged 50 to 59 years stabilized within 30 seconds of standing, with older groups taking 30 seconds or longer. The total prevalence of impaired BP stabilization was 15.6% (95% confidence interval [CI], 14.1%–17.1%), increasing with age to 41.2% (95% CI, 30.0%–52.4%) in people ≥80 years old. Initial orthostatic hypotension occurred in 32.9% (95% CI, 31.2%–34.6%) of the population aged ≥50 years, with no age gradient evident. The prevalence of orthostatic hypotension was 6.9% (95% CI, 5.9%–7.8%) in the total population, increasing to 18.5% (95% CI, 9.0%–28.0%) in those aged ≥80 years old. Conclusions— Significant age-related differences exist in the time course of postural BP responses, with abnormal responses taking longer than 30 seconds to stabilize. Impaired BP stabilization is more common as we age, affecting more than two-fifths of the population aged ≥80 years, and may play a future role in the management of falls and syncope.

Health and Aging: Development of The Irish Longitudinal Study on Ageing Health Assessment

To assist researchers planning studies similar to The Irish Longitudinal Study on Ageing (TILDA), concerning the development of the health assessment component, to promote use of the archived data set, to inform researchers of the methods employed, and to complement the accompanying article on normative values.

Orthostatic Hypotension Is Associated With Lower Cognitive Performance in Adults Aged 50 Plus With Supine Hypertension

OBJECTIVES This study investigated the association between orthostatic hypotension (OH), supine hypertension (SH), and cognitive performance. METHODS Four thousand six hundred and ninety participants of The Irish Longitudinal Study on Ageing (TILDA) were studied. SH was defined as systolic blood pressure (SBP) greater than or equal to 140 mmHg and/or diastolic blood pressure (DBP) greater than or equal to 90 mmHg, measured following supine rest (10 minutes). OH was defined as a sustained drop of greater than or equal to 20 mmHg SBP or greater than or equal to 10 mmHg DBP at 20, 30, 60, and 90 seconds following orthostasis. Cognitive performance tests assessed global function, executive function, processing speed, memory, and attention from which z-scores were computed. Multivariate adjusted analysis was performed comparing cognitive scores by OH status overall and in SH and non-SH groups separately. RESULTS Thirty-nine percent had baseline SH (n = 1,868) and demonstrated a greater orthostatic fall in SBP (p < .0001) and DBP (p < .0001). This group had a higher prevalence of OH at all time-points, and scored lower in tests across all cognitive domains. No overall association between OH and cognitive performance was seen. However, SH subjects with OH scored significantly worse (adjusted) than SH subjects without OH, in domains of global cognition (30 seconds poststand β = -0.15; 99% confidence interval -0.29, -0.14; p = .004) and executive function (20 seconds poststand; β = -0.11; 99% confidence interval -0.22, -0.01; p = .006). There was also an indication toward lower cognition in all nonsignificant analyses. OH was not associated with cognitive performance in non-SH subjects. CONCLUSION In conclusion, individuals with SH (defined as BP > 140/90 mmHg) coupled with OH measured using phasic BP had lower global and executive cognitive performance than those with SH but without OH.

Sustained Attention and Frailty in the Older Adult Population

OBJECTIVES We investigated whether sustained attention performance and variability were associated with prefrailty and frailty in the older adult population. METHOD A total of 4,317 participants aged 50 years and over from the Irish Longitudinal Study on Ageing (TILDA) completed a comprehensive health assessment. Frailty was defined by low gait speed, low grip strength, unintentional weight loss, self-reported exhaustion, and low physical activity. Scores of greater than or equal to 3, 1-2, and 0 indicated that participants were frail, prefrail, and nonfrail, respectively. Multinomial logistic regression computed associations between frailty state and measures of performance and variability on the Sustained Attention to Response Task (SART). Cognitive processing speed and executive function were also measured. RESULTS Mean reaction time (RT; odds ratio [OR] = 1.13, p < .05) and RT variability reflective of the top-down aspect of sustained attention (OR = 1.11, p < .05) were associated with prefrailty in the 50-64 age group. Mean RT (OR = 1.72, p < .05) was associated with frailty and RT variability (OR = 1.22, p < .01) with prefrailty in the 65+ age group. Results remained significant following adjustments for cognitive processing speed, executive function, chronic conditions, medications, age, and gender. DISCUSSION Sustained attention performance and variability were associated with prefrailty and frailty in the older adult population and may represent a novel, objective, and modifiable cognitive marker of frailty progression.

Cognitive performance in orthostatic hypotension: findings from a nationally representative sample.

To compare the cognitive profile of a population representative sample with orthostatic hypotension (OH) with the profile of a sample without.

Antidepressants strongly influence the relationship between depression and heart rate variability: findings from The Irish Longitudinal Study on Ageing (TILDA)

Background Heart rate variability (HRV) is known to be reduced in depression; however, is unclear whether this is a consequence of the disorder or due to antidepressant medication. Methods We analysed data on 4750 participants from the first wave of The Irish Longitudinal Study on Ageing (TILDA). Time [standard deviation of normal to normal intervals (SDNN ms2)] and frequency domain [low frequency (LF) and high frequency (HF)] measures of HRV were derived from 3-lead surface electrocardiogram records obtained during 10 min of supine rest. Depression was assessed using the Center for Epidemiologic Studies – Depression scale. Results Participants on antidepressants [with (n = 80) or without depression (n = 185)] differed significantly from controls (not depressed and not taking antidepressants n = 4107) on all measures of HRV. Depressed participants not taking antidepressants (n = 317) did not differ from controls on any measures of HRV. In linear regression analysis adjusted for relevant factors all antidepressants were associated with lower measures HRV. Participants on selective serotonin reuptake inhibitors (SSRIs) had higher measures of HRV relative to participants on tricyclic antidepressants or serotonin–norepinephrine reuptake inhibitors respectively. Conclusions Our results suggest that reductions in HRV observed among depressed older adults are driven by the effects of antidepressant medications. SSRIs have less impact on HRV than other antidepressants but they are still associated with lower measures of HRV. Study limitations include the use of a self-report measure of depression and floor effects of age on HRV could have limited our ability to detect an association between HRV and depression.

Parasympathetic autonomic dysfunction is common in mild cognitive impairment.

Components of the central autonomic network attract the greatest neurofibrillary degeneration and related cell death during the course of Alzheimers disease (AD). The insular cortex and brainstem are affected from the early stages of disease. Acetylcholine, the main neurotransmitter of the parasympathetic system may be deficient in mild cognitive impairment (MCI). Hence, autonomic dysfunction may be a novel biomarker of neurodegeneration. Autonomic function was examined in 97 MCI participants and 36 controls using beside cardiovascular reflex tests and heart rate variability. The association between dysautonomia and neuropsychiatric deficits was examined. This observational study was conducted in a clinical setting. MCI participants showed significant parasympathetic deficits in bedside cardiovascular reflex tests and heart rate variability compared with controls. Those with more significant autonomic dysfunction had more severe neuropsychological deficits. MCI participants were 5.60 (95% confidence interval, 1.6-27.2) times more likely than a control to have autonomic dysfunction. Autonomic dysfunction, particularly parasympathetic dysfunction is prevalent in MCI. This may be due to early neuroanatomical and neurochemical changes in the central autonomic network in Alzheimers disease. This may accelerate cognitive decline via proinflammatory mechanisms and/or hypotension-induced cerebral hypoperfusion. This provides insight into the pathophysiological mechanisms that contribute to cognitive decline, and may lead to the development of effective therapeutic interventions.

Impaired Orthostatic Blood Pressure Recovery Is Associated with Unexplained and Injurious Falls

Cardiovascular disorders are recognized as important modifiable risk factors for falls. However, the association between falls and orthostatic hypotension (OH) remains ambivalent, particularly because of poor measurement methods of previous studies. The goal was to determine for the first time to what extent OH (and variants) are risk factors for incident falls, unexplained falls (UF), injurious falls (IF) and syncope using dynamic blood pressure (BP) measurements in a population study.