Susan W. Muir PT PhD. Post-Doctoral Fellow Division of Geriatric Medicine Schulich School of Medicine & Dentistry University of Western Ontario

Transcription

1 Susan W. Muir PT PhD Post-Doctoral Fellow Division of Geriatric Medicine Schulich School of Medicine & Dentistry University of Western Ontario University of Toronto Rehabilitation Rounds June 14,

2 Demographic shift Stat Can released recent census data on age Impact on health care Geriatric Giants Postural instability Cognitive impairment Falls Dementia 2

3 Requires the integration of information from multiple systems: Vision Somatosensory system Vestibular system Motor system Reaction time Cognition (Horak 2006 ) 3

4 Coordination of motor and sensory systems Linked by higher order neurological processes and cognition Perception of environmental stimuli Responding to alterations in the body s orientation in the environment to control body movement (Horak 2006; Lord et al 2007) 4

5 Neuroanatomy of Postural Stability Executive Function Memory 5

6 Pathology Alzheimer Disease 30-50% gait disorders Impaired brain structures Frontal-subcortical circuits Hippocampus Annweiler C & Montero-Odasso M. Am J Alzheimers Dis (under review) 6

7 Cognition has a key role in the regulation of gait and balance (Woollacott & Shumway-Cook 2002) Gait and balance: should be treated as a higher level of cognitive functioning (Hausdorff et al. 2005) Higher level cognitive domains Executive function, attention 7

8 Falls in older adults are a common event 30% community-dwelling adults over 65 will fall at least once each year 50% will have recurrent falls 50% will sustain an injury 10-15% suffer serious injury 2-6% suffer a fracture % suffer a hip fracture (PHAC 2005) 8

9 Prominent falls risk factors: History of falls Balance impairment Gait impairment Basis for clinical practice guidelines for prevention of falls in older adults Key falls risk factors are within the clinical domain of physiotherapy 9

10 AGS & BGS Falls Prevention Guidelines 2011 Any falls in the past year? No falls No intervention Recurrent falls Single fall Check for gait/balance problem No problems Gait/balance problems Fall Evaluation 10

11 ((Muir et al. J Geriatr Phys Ther. 2010) How many falls have you had in the last year? N = 117 None (Box A) Fall risk = 29% n=58 One only Fall risk = 47% n = 36 Two or more (Box D) Fall risk = 74% n = 23 Balance/gait impairment? No (Box B) Fall risk = 40% n = 21 Yes (Box C) Fall risk = 60% n = 15 No intervention recommended and monitor yearly Fall risk = 33% n = 79 Fall evaluation indicated Fall risk = 68% n = 38 11

12 29% fell over 12 months (Muir et al. Physiother Can 2010) 12

13 Balance Measure Number (%) identified as impaired on testing Self-report of balance problems Mean total BBS Score (impaired/non-impaired) Absolute fall risk (%) Risk difference (95%CI) 53 (30%) 45.2/ % 19% (2%, 37%) One leg stand 114 (63%) 47.9/ % 22% (6%, 37%) Tandem stand 79 (43%) 45.6/ % 12% (0%, 27%) Limits of stability 43 (24%) 42.0/ % 17% (0%, 35%) Unsteady gait 31 (17%) 38.6/ % 18% (3%, 39%) (Muir et al. Phys Ther. 2010) 13

14 Berg Balance Scale (Muir et al. Phys Ther. 2008) had good discriminative ability to predict multiple falls threshold of 45, was inadequate to identify the majority of future fallers Sensitivity: 25% for any fall 45% for multiple falls Dichotomizing scale not recommended AUC=

15 Balance Measure Univariate Analysis (RR) Adjusted Analysis* (RR) P-value Self-report of balance problems 1.58 (1.14, 2.19) 1.58 (1.06, 2.35) 0.02 One leg stand 1.73 (1.15, 2.61) 1.58 (1.03, 2.41) 0.04 Tandem stand 1.30 (0.93, 1.82) 1.26 (0.76, 1.90) 0.18 Limits of stability 1.44 (1.02, 2.01) 1.46 (1.02, 2.09) 0.04 Unsteady gait 1.46 (1.02, 2.09) 1.24 (0.86, 1.80) 0.25 Sum of balance impairments 1.18 (1.05, 1.32) 1.20 (1.04, 1.39) 0.01 *, adjusted for age ( 80 years), sex, number of prescription medications ( 4), history of falls in the previous 12 months, treatment group in PPFV;, sum of impairment on one leg stand, tandem stand, limits of stability and unsteady gait. (Muir et al. Phys Ther. 2010) 15

16 Why focus on this group of older adults? 16

17 Multifactorial fall prevention programs not successful in the cognitively impaired for MMSE < 20 (Hauer et al 2006; Tinetti 2004; Jensen 2003) People with cognitive impairment excluded from studies on interventions Limited research (Hauer 2006; Oliver 2007) Adaptations to meet the needs of this population (Shaw 2007) 17

18 Older adults with cognitive impairment: Can comply with: Multifactorial interventions (Shaw 2003) Programs to improve physical function (Brill 1995; Jensen 2003) Complex exercise programs (Schwenk 2010) Post hip fracture make gains comparable to the cognitively normal on inpatient rehab (Muir & Yohannes 2009) Exercise training increases fitness, physical function, cognitive function, and positive behavior (Heyn 2004) 18

19 19

20 Benign age-associated changes Mild Cognitive Impairment prevalence 16-20% adults over age 65 years Dementia prevalence 80% Alzheimer s disease 8% at age 65 35% over age 85 55% living in the community Majority of cases are undiagnosed 20

21 What do we mean by Cognitive Impairment? Disease-specific diagnosis Deficits on measures of global cognitive function Deficits in specific cognitive domains Need to be clear what we mean by cognitive impairment Essential in order to translate the research into clinical practice 21

22 Systematic review and meta-analysis: (Muir et al. Age Ageing. 2012) Cognitive impairment not consistently associated with falls 56% of studies positive association Measures of global cognitive function (i.e. MMSE) Only 38% found positive association Measures of executive function consistently associated 22

23 Meta-analysis results: Fall Outcome Odds Ratio (95% CI) I 2 (%) Any fall community-dwelling 1.32 (1.18,1.49) 74.3% Serious injury community-dwelling 2.33 (1.61,3.36) 5.9% Fractures community-dwelling 1.78 (1.34,2.37) 0% Any fall institution-dwelling 1.78 (1.34,2.37) 46.7% Any fall executive function impairment 1.44 (1.20,1.83) 70.9% 23

24 Two important considerations with different intents: How does cognitive impairment influence the person s ability to follow instructions? Reliability How does the cognitive impairment influence the physical performance? Challenging the cognitive role in postural stability Impairment sub-clinical 24

25 Dual-task paradigm Observing people during a gait or balance task while they perform a secondary task Stops walking while talking (Lundin Olsson 1997) Relevant Most activities of daily living involve the simultaneous performance of two or more cognitive and motor tasks Representative of real life situations where falls are likely to occur 25

26 Balance in the Cognitively Impaired A. Control RS_EO RS_ES DS_EO DS_ES B. Alzheimer s disease 26

27 Cognitive Test Clinical Test for Balance Function BBS TUG TUG-cog BST BST-cog FABS MMSE No No YES No No No MoCA No No YES No No YES TMT-a YES YES YES No No YES TMT-b YES YES YES No No YES * Multivariable linear regression adjusted for age and history of falls. 27

28 TUG-cog TUG 28

29 Controls MCI AD Gait Variable Group Usual Gait Naming Animals Serial Sevens Repeated Measures Two-way ANOVA* (p-value) Gait Velocity (cm/sec) Control (n=16) MCI (n=18) AD (n= 19) (21.50) (28.16) (26.30) Group <0.0001* Condition Interaction * (20.82) (27.98) (27.69) (14.39) (26.53) (26.55) 29

30 Controls MCI AD Gait Variable Group Usual Gait Naming Animals Gait Variability (CoV) Control (n=16) MCI (n=18) AD (n=19) Serial Sevens Repeated Measures Two-way ANOVA* (p-value) 1.70 (0.63) 2.17 (1.09) 2.82 (1.28) Group * Condition Interaction (1.47) 8.91 (10.98) 9.08 (8.02) 2.41 (0.56) (18.30) (11.85) 30

31 CONCLUSIONS: Cognitive impairment imparts a moderate increase risk for falling Executive function evaluation should be part of a falls assessment Reliable and valid methods to assess interplay of physical and cognition function Dual-task testing 31

32 Assessment protocols for balance using dualtask paradigm to identify future fall risk Association established for gait Contradictory for balance Literature doesn t allow knowledge translation Need to know prognostic test properties Prospective cohort Novel populations of older adults Rigorous statistical methodology 32

33 Neurorehabilitation protocols to improve balance and decrease falls Older adults with cognitive impairment Novel intervention regimens Dual-task training Cognitive training in conjunction with balance rehabilitation Quantifying change over time in this population 33

34 Factors that influence functional recovery among older adults admitted for inpatient rehabilitation Fall-related injuries Prognostic factors and interaction Outcomes post-discharge CIHR Institute of Aging Functional autonomy & cognition = priority research themes 34

35 PhD Thesis Committee, Dept of Epidemiology Dr. Mark Speechley Dr. Neil Klar Dr. Bert Chesworth Dr. Katherine Berg Post-Doctoral Fellowship: Gait & Brain Lab, Parkwood Hospital Dr. Manuel Montero Odasso Karen Gopaul, Anam Islam, Shamis Nabeel, Cedric Annweiler Aging and Brain Memory Clinic, Parkwood Hospital Dr Jennie Wells Dr Michael Borrie Janyth Mowat Funding Agencies Alzheimer Society of Canada Ontario Rehabilitation Coalition 35

36 THANK YOU Questions? 36