Journals of Gerontology: MEDICAL SCIENCES Cite journal as: J Gerontol A Biol Sci Med Sci doi:10.1093/gerona/glt166

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Neuropsychological, Physical, and Functional Mobility Measures Associated With Falls in Cognitively Impaired Older Adults Morag E. Taylor,1,2 Kim Delbaere,1,3 Stephen R. Lord,1,3 A. Stefanie Mikolaizak,1,3 Henry Brodaty,4–6 and Jacqueline C. T. Close2,7 Falls and Balance Research Group, Neuroscience Research Australia, 2 Prince of Wales Clinical School, Medicine, 3 School of Public Health and Community Medicine, Medicine, and, 4 Dementia Collaborative Research Centre, School of Psychiatry, Medicine, UNSW, Sydney, Australia. 5 Academic Department for Old Age Psychiatry, Prince of Wales Hospital, Randwick, Australia. 6 Centre for Healthy Brain Ageing, School of Psychiatry, Medicine and, 7 Falls and Injury Prevention Group, Neuroscience Research Australia, UNSW, Sydney, Australia. 1

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Address correspondence to Jacqueline C. T. Close, MBBS, MD, Neuroscience Research Australia, Barker Street, Randwick, Sydney, NSW 2031, Australia. Email: [email protected]

Background.  Older people with cognitive impairment have an elevated fall risk, with 60% falling annually. There is a lack of evidence for fall prevention in this population, in part due to limited understanding of risk factors. This study examined fall risk in older people with cognitive impairment with an emphasis on identifying explanatory and modifiable risk factors. Methods.  One hundred and seventy-seven community-dwelling older people with mild–moderate cognitive impairment (Mini-Mental State Examination 11–23/Addenbrooke’s Cognitive Examination–Revised 60 years, living in the community or a low-level care facility and having an identified “person responsible” with at least 3.5 hours of faceto-face contact per week. CI was defined as a Mini-Mental State Examination score 11–23 inclusive (5) (Figure 1a), an Addenbrooke’s Cognitive Examination–Revised (ACE-R) < 83 (6) (Figure 1b), or a diagnosis of CI or dementia by a specialist clinician (Figure 1a and b). Exclusion criteria included: recent stroke (within 18 mo), progressive neurodegenerative disorders (excluding dementia), insufficient English to complete the tasks or known end-stage illness. The study was approved by the South East Sydney Human Research Ethics Committee and consent was obtained from all participants and their persons responsible prior to assessment. All participants were stable at home for a minimum of 6 weeks prior to assessment confirmed by their carer or person responsible. Baseline Assessment Demographics, medical, and medication measures.— Participants and their persons responsible were interviewed at home for demographic characteristics,

medical history, medication use, and usual level of function. Medications included in the classification of “Central nervous system acting medication” were opioids, anticonvulsants, antipsychotics, anxiolytics, hypnotics and sedatives, antidepressants, and antidementia drugs. Orthostatic hypotension was defined as a ≥20 mmHg systolic and/or a ≥10 mmHg diastolic drop in blood pressure on standing at 1 or 3 minutes. Physical activity.—The Incidental and Planned Exercise Questionnaire was administered, with the assistance of carers, to obtain information on total hours of physical activity, total hours of walking activity, total hours of incidental activity, and total hours of planned exercise over the past week (7). Neuropsychological function.—The neuropsychological test battery consisted of a number of well-validated and commonly used measures of cognitive performance including the ACE-R, Trail-Making Test (A and B), the Boston Naming Test–short form and logical memory. The ACE-R includes the Mini-Mental State Examination but also measures a broader range of cognitive domains, which include attention and orientation, memory, verbal fluency, visuospatial, and language skills (6). The ACE-R has good reliability and a cutoff of 82 has excellent sensitivity (0.84) and specificity (1.00) for dementia (6). The cube and clock drawing are also contained within the ACE-R. Trails A  and B measure visual search and processing speed (8). Trails B measures divided attention, mental flexibility, and executive function (8). The executive component of the Trail-Making Test was ascertained by subtracting Trails A from B. Verbal fluency and the clock drawing also measure executive function (9). The Boston Naming Test measures confrontational naming (10). Logical memory assesses memory and involves verbal presentation of story A.  Immediate and delayed recall (approximately 30 min) were assessed, as well as delayed recognition—15 questions requiring a yes or no response (11). Depression, anxiety, and concern about falling.—The 15-item Geriatric Depression Scale (GDS) assessed mood (12), the Goldberg Anxiety Scale assessed anxiety, and the seven-item Falls Efficacy Scale–International assessed concern about falling and has been demonstrated to have excellent reliability and good to excellent validity in people with CI (13,14). Sensorimotor function.—These measures of sensorimotor function were chosen as they have previously been shown to be associated with falls and have excellent (visual contrast sensitivity, knee extension strength) or fair to good (proprioception, reaction time) reliability in older people (15). Visual contrast sensitivity was assessed

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balance, have consistently been associated with CI (2,3), and are also known risk factors for falls. Impaired gait and balance can partially be attributed to central neurodegenerative processes in dementia. Motor tasks such as walking are complex processes that require integration of both sensorimotor and cognitive systems. Slowed cognitive processing speed may fail to compensate for impairments of sensorimotor systems and compromise motor planning and responses required for maintaining balance in challenging environments. Previous studies have identified fall risk factors such as psychotropic drug use, autonomic dysfunction, depression, symptomatic orthostatic hypotension, and periventricular white matter lesions in community-dwelling older people with CI (1,4). These studies have explored a limited range of potential risk factors. Further examination of a broad set of neuropsychological, physical, and functional mobility measures is required to identify key explanatory and modifiable risk factors and assess the relative importance of each factor in predisposing older people with CI to falls. This large, prospective study builds on previous work by administering a multidomain risk factor assessment to a sample of community-living older people with CI and prospectively determining fall outcomes over 12 months. The ultimate aim is to facilitate more effective approaches to fall prevention in this high-risk population.



RISK FACTORS FOR FALLS IN DEMENTIA

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using the Melbourne Edge Test (15). Simple hand reaction time (ms) was measured using a visual stimulus and a finger-press response (15). Proprioception was measured using a lower limb–matching task; errors in degrees were recorded (15). Maximum grip strength was recorded with a hydraulic hand dynamometer (North Coast Hydraulic Hand Dynamometer; North Coast Medical Inc., Morgan Hill, CA) in the dominant hand (best of three, kilograms force). Maximal isometric knee extension strength was measured in the dominant leg (best of three, kilograms force) (15). Standing balance.—Postural sway was assessed using a swaymeter that measures displacement of the body at waist level with participants standing on a firm surface and a foam rubber mat (15-cm thick) with eyes open for 30 seconds (15). Sway score (mm2) was calculated using mediolateral sway displacement × anteroposterior sway displacement. Sway on floor and foam have previously been demonstrated to be associated with falls in older people and have acceptable reliability (intraclass correlation coefficient 0.68 and 0.57, respectively) (15,16).

Standing balance (eyes open, barefoot) was assessed by recording the time (for a maximum of 10 s) each of the following foot positions could be held without support; apart, together, semitandem (heel of one foot in the instep of the other), near-tandem (heel of one foot 2.5cm anterior and laterally to the great toe of rear foot) and tandem (17). Near-tandem was also assessed with eyes closed as this measure has previously been shown to be significantly associated with falls with moderate reliability (18). Functional mobility.—These functional mobility measures were chosen as they have been associated with falls in older people and have very good to excellent reliability in older people with (9,19,20) and without dementia (16,18,21). Functional mobility was assessed using coordinated stability (19,21), timed-up-and-go (9,20,22), and five-repetition sit-to-stand (20,23) tests. The co-ordinated stability test assesses leaning balance and measures the ability to adjust body position in a steady and coordinated way while navigating a pen on the end of a rod (secured to the participant’s waist) around a convoluted

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Figure 1. (a) Percentage of participants in each Mini-Mental State Examination (MMSE) score bracket. (b) Percentage of participants in each Addenbrooke’s Cognitive Examination–Revised (ACE-R) score bracket (likelihood ratio of dementia = 100 if score

Neuropsychological, physical, and functional mobility measures associated with falls in cognitively impaired older adults.

Older people with cognitive impairment have an elevated fall risk, with 60% falling annually. There is a lack of evidence for fall prevention in this ...
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