1. RIPPS: Repeated Incremental Predictable Perturbations: Balance Tool; Clinical Applications APTA Combined Sections Meeting San Diego, CA January 21-24, 2013 Louis DePasquale PT, MA Bon Secours Health System Francis Schervier Long Term Home Health Riverdale, New York 1

2. RIPPS: Course Objectives  ID issues re: balance and timed performance measures in active older adults  ID RIPPS performance criteria and RIPPS test end points  Administer RIPPS protocol and obtain RIPPS % TBW measurements  Interpret RIPPS % TBW scores 2

3. RIPPS: Course Objectives  Apply current postural control evidence to RIPPS testing and interpretation  Apply motor learning evidence to develop RIPPS intervention strategies  Document RIPPS % TBW measures 3

4. RIPPS Balance Assessment Evidence-Based: The Spring Scale Test (SST): A Reliable and Valid Tool for Explaining Fall History. (DePasquale L, Toscano L, JGPT: 2009;32(4). 4

5. RIPPS: Course Outline  Overview  Falls: Clinical challenges  Perturbation studies: historical  RIPPS Protocol: SST Evidence  RIPPS: Foundations: aging, neurophysiology  RIPPS: Applications 5

6. RIPPS: SST Evidence Overview  Repeated cycles of loading/unloading  Predictable 1 lb.   Anterior: rear step  Posterior: fwd step  Load: Foot flat  Unload: 3 step limit  % TBW measure  FIRST TRIAL 6

7. Why RIPPS? Falls and Risks  Most falls occur while walking, requiring proactive and reactive postural responses. (Harris J, et al. PTJ, 2005). 1  Incidence and prevalence of gait disorders is high in community- residing older adults.  Early ID of gait impairment may ID high-risk individuals and provide opportunity to provide interventions to  progression of impairment. (Verghese J, et al. J Am Ger Soc. 2006). 2 7

8. Why RIPPS? Falls Data  Fall history is most commonly used to ID  risk for future falling.  Falls are the leading cause of injury in adults aged 65 years or older.  30 % - 40 % of community living older adults aged 65 years and older fall at least once per year. (Moyer V, Annal Int Med, 2012). 3 8

9. Why RIPPS? Falls Impact  Fall risk for community-living older adults is an urgent public health problem. (Renfro, JGPT 2011). 4  20-30% falls result in hip fracture or head trauma with  mobility, balance and force production with  fall risk. (Mangione, PTJ 2005). 5 9

10. Why RIPPS? Fall Risk ID  Difficult to ID fall risk in active older adults  Current tests not predictive to fall status in the active community- dwelling older adults. (Boulgarides PTJ 2003) 6 10

11. Why RIPPS: Current Tests  TUG, SLST, BBS, POMA, FR, TST are less predictive of falls in the community active population with fewer health problems (Boulgarides PTJ 2003, Lin S, Woollacott M, Age Aging 2005, Muir S, PTJ 2010, Lin MR, JAGS 2004, Buatois S, et al PTJ 2010, Neul P, et al. JGPT 2011). 6-11 11

12. Why RIPPS? Fall Risk ID  Observational gait assessment and tandem stance are not statistically associated with  risk for any fall; 12 mo. prospective study. (Muir S, Berg C, et al. PTJ 2010). 8  Current balance measures: ceiling effects, low sensitivity to change and responsiveness, have limited use for community population. (Pardasaney P, Latham N, Jette A, PTJ, 2012). 12 12

13. Why RIPPS? Fall Risk ID Certain balance and timed mobility performance measures are unable to explain falls due to:  intrinsic ceiling effects.  compromised sensitivity due to lack of variability in maximum performance scores.  lack of responsiveness in active older adults. (Pai YC, JGPT, 2010). 13 13

14. Why RIPPS? Fall Risk ID  New tools should contain more challenging performance-based measures. (Boulgarides, PTJ, 2003). 6  Tests involving responses to externally imposed perturbations need attention of researchers. (Harris, PTJ, 2005). 1 14

15. Why RIPPS? Reactive Balance  Reactive balance in the elderly needs to be specifically addressed. 7 (Lin S, Woollacott M, Age Aging, 2005).  The clinical examination of reactive balance control is not standard practice. (Mansfield PT. 2011; 91(6) Training rapid stepping responses in an individual with stroke). 14 15

16. Why RIPPS? AGS  The American Geriatric Society (AGS) 2011 revised guidelines recommend that all adults aged 65 years and older be screened ANUALLY for falls.  CMS Expanded guidelines include annual screening for balance and mobility impairments. 16

17. RIPPS: Take Home Message  New tests needed for active aging population.  Challenging performance based measures.  Need to reveal fall related deficits in the high functioning older adult.  Early ID of mild balance dysfunction. 17

18. Perturbation Studies Historical Perspective 18

19. Perturbation Studies: Review  Laboratory: random platform or waist pull methods, reactive biased, not clinically feasible.  Percent of total body weight (% TBW) units of force / performance measure described. 19

20. 1986 Wolfson, Whipple, AGS Stressing the Postural Response 15  PST predictable uni-direction  1.5/3/4.5 % TBW posterior waist pulls  fallers/young & old controls  Old non-fallers: 2-3 rear steps  Normals: 1-2 well controlled steps  Responses video taped, scores assigned  Multiple observations; feasibility? 20

21. 1988 Lee, Deming, PTJ Static loading limits in post stroke 16  Predictable loading to foot flat limits  Young & older normal, post CVA  Anterior/posterior/left/right  Begin at 1 lb, increase by 1% TBW  [5.8p – 7.1p / 8.4a-11.4a] Old Healthy [4.2p – 6.1p / 7 a – 9.2a ] CVA  Lower % TBW posterior direction 21

22. 1990 Chandler, Duncan, Studenski, PT Balance Performance on PST 17  PST protocol (Wolfson and Whipple)  Predictable sudden weight drop  @4.5% limit healthy older: 1-3 steps  Half of the fallers withstood 4.5% TBW 22

23. 1994 Luchies C, et al. J Am Ger Soc. Stepping responses of young and old. 18  Young and old healthy adults  Sudden backward waist pulls  At large disturbance levels: Young - single step mostly Older - multiple shorter steps - earlier step thresholds 23

24. 2003 Rogers et al, Jl Gerontol Step training improves speed of voluntary step initiation in aging 19  Displacing perturbations (53/session)  3 weeks, 2 times per week training  Perturbation-induced step training resulted in  response time compared to voluntary step practice  Voluntary and IND stepping resulted in improved step initiation (IT). 24

25. 2004 Jöbges et al, Jl Neuros Psych: rep. training of compen. steps PD. 20  10% TBW dropped 78cm (L/R-A/P) pre/post test; thoracic harness  Training via manual pull/push method  5 reps each direction; large step cues  Results:  compensatory step length; 2 month retention;  step initiation time;  gait speed 25

26. 2005 Schultz et al. Gait Posture Compensatory stepping in response to waist pulls in BI and UI women. 21  AP waist pulls 1-5% TBW unpredictable  BI required more steps  Feet in place strategies may dissipate some perturbation force for  stability  Torso flexion during forward stepping could increase instability  First step critical in  COM velocity  Lateral stepping is inefficient during rear stepping, wasted effort and time. 26

27. 2007 Pai, Bhatt, PT Repeated slip-training; Emerging paradigm. 22  Unpredictable slip perturbations during repeated stand/sit trials and walking  Highly threatening environment  Single acquisition session  Long term retention of motor behavior  Older adults can rapidly develop adaptive skills similar to young adults 27

28. 2009 DePasquale L,Toscano L, JGPT (SST). 23  Predictable 1 lb  anterior/posterior  Active independent living older adults  Fallers and non-fallers clinical setting  Reliable and valid clinical tool for ID fall history  RIPP forces 10 % TBW critical threshold for ID fall risk. Feasible 28

29. 2010 Mansfield, PT Perturbation-based program on compensatory stepping and grasping older adults RCT. 24  Platform/waist-pulls at 20% TBW  Unpredictable 4 directions  Stepping/grasping responses elicited  Potential for perturbation- based balance training to  fall risk in older adults  High forces, feasibility? 29

30. 2010 Pai et al. JGPT Adaptability to perturbation as a predictor of future falls: Preliminary prospective. 13  Slip perturbations during rapid repeated stand/sit trials unannounced  Slip/non-slip blocks total 14 trials  Adaptations to perturbations may be linked to fall risk  High risk method, feasibility? 30

31. 2011 Mansfield, PT, Training rapid stepping responses in an individual with stroke: Case report. 14  Lean/release perturbation system  % TBW associated with dorsi flexion angle (11% TBW / 9 degrees df)  Evoking compensatory stepping responses  Increase use of affected limb stepping  Obstacle step clearance  Force and joint angle measurement? 31

32. RIPPS Evidence Spring Scale Test 32

33. RIPPS Evidence: SST Method  Retrospective descriptive same day test-retest repeated measures reliability 4 examiners.  Convergent validity: OLST, TST, TUG, VEL.  Discriminant validity: Log. regress., ROC/AUC  58 active, independent community- living adults subjects ages 65-90+  N=29 no fall history; N= 29 fall history in past 2 years. 33

34. RIPPS Evidence: SST Method Decade Distribution Data  6 @ 65 to 69 yrs.  16 @ 70 to 79 yrs.  30 @ 80 to 89 yrs.  6 @ 90 + yrs. 34

35. RIPPS: SST Evidence Faller Characteristics N = 29MinimumMaximumMeanStd. Dev. Age759483.65.55 Weight (lb) 106200145.826.4 Weight (kg) 48.190.766.2211.97 Height (m) 1.351.851.640.11 BMI (index) 17.834.424.53.27 SF-36 score 25.095.063.318.58 35

36. RIPPS: SST Evidence Non-faller Characteristics N = 29MinimumMaximumMeanStd. Dev. Age659078.07.75 Weight (lb) 103200153.028.8 Weight (kg) 46.790.769.412.78 Height (m) 1.481.831.670.089 BMI (index) 19.432.524.93.12 SF-36 score 55.0100.086.212.15 36

37. RIPPS: SST Evidence Sample Characteristics 37

38. RIPPS Evidence: Fall Definition  Fall Definition: any unintentional loss of balance during routine activities resulting in contact with any lateral or lower level support surface (ground included) by any body part other than feet. (Boulgarides, PTJ, 2003). 6 38

39. RIPPS: SST Evidence Participant Inclusion  TUGT under 14 seconds  Ability to walk independently 1+ blocks  No walker devices, canes OK (n=3)  Medically stable no pain / 3 mos. post hosp/fx  200 pounds body weight limit  Ankle  DF 3/5 and AROM  10 degrees  Heel height and floor surfaces controlled 39

40. RIPPS: SST Evidence Reliability Test Re-test  Same day: 2 SST trials 15 min apart, 2 examiners. 4 examiners participated in study.  Vital signs, age, wt, ht, leg/foot length, SF-36 short form, slst, tug, tst, vel., fall hx.  45 minutes avg. in-home completion time.  Data collection from 6/07 to 12/07.  No drop outs/adverse outcomes or responses. 40

41. RIPPS: SST Evidence Instrumentation  8-inch pocket-sized linear spring scale (Pelouze/Pelstar) 26 pound capacity.  1 pound units with calibration dial.  Scale calibrated with 5lb wt. prior to & mid point of each test day.  Securely affixed to 5-inch padded belt secured at the waist. 41

42. 42 RIPPS: SST Protocol Setup  Scale / feet in view  4-foot tether strap  Client faces examiner: anterior test  Client’s back to examiner: posterior test  % TBW Score  Support surface 3 feet

43. RIPPS: SST Evidence Protocol  Normal stance, waist belt secured with spring scale affixed midline orientation, tether strap.  AP saggital plane linear, horizontal 1 lb. incremental accommodative loading.  quasi-random (5s) unloading at each new 1lb increment force.  Limits of foot-flat accommodation or effective stepping (3 step limit) expressed as %TBW.  First attempt, single trial test. 43

44. RIPPS: SST Anterior DLT - Loading  Continuous / cyclic  Accommodative  1 lb. increments  Ongoing instruction  % TBW score  End point: heel lift or fwrd. step 44

45. RIPPS: SST Anterior DLT Unloading - Rear Stepping  1 pound increments  Quasi-random release 5 second window  3 step limit criteria  % TBW score  End point: + 3 steps or contact with compliant surface 45

46. RIPPS: SST Posterior DLT Loading  Continuous / cyclic  1 pound increments  Accommodative  Ongoing instruction  End point: Sole lift or rear step  % TBW score 46

47. RIPPS: SST Posterior DLT Unloading - Forward Step  5 sec quasi-random  1 pound increments  3 step limit criteria  Forward step limits  % TBW score  End point: + 3 steps or contact with compliant surface 47

48. RIPPS: Sequence summary  Anterior direction: rear stepping  Preliminary loading to foot flat limit  RIPPS loading / unloading to end point limits  Anterior direction limit ADL % TBW score  Posterior direction: forward stepping  Preliminary loading to foot flat limit  RIPPS loading / unloading to end point limits  Posterior direction limit PDL % TBW score 48

49. RIPPS: % TBW Clinical Performance Measure  2 Direction Limit (DL)%TBW scores: anterior and posterior.  RIPPS % TBW clinical performance measure = Lower DL % TBW score.  % TBW = limit force in pounds divided by obtained body weight. 49

50. RIPPS: SST % TBW Measures Direction Limit Scores  End point force = (failure), not DL % TBW score.  Direction Limit % TBW scores: highest loading/unloading force achieving RIPPS criteria.  Example: failure at 10 pounds denotes in a DL force value of 9 pounds. (9%TBW for 100 pound body weight). 50

51. RIPPS: GRID 51 [#= steps] [T / L] [.X= decimal portion of % TBW]

52. RIPPS: Documentation Ideas  RIPPS % TBW score = lower DL % TBW  DL: % TBW values both directions  DL: number of steps  10% TBW number steps  Threshold % TBW / # steps  Trials 1-2?  Ankle / hip strategy % TBW limits 52

53. 53 RIPPS: SST Protocol Elements  1 pound incremental predictable loading  Single trial  Performance Criteria: Loading: foot-flat accommodation Unloading: 3 step limit  2 DL % TBW scores  RIPPS % TBW clinical performance measure: Lower DL % TBW score

54. RIPPS: Technique Notes Demonstration  Obtain body weight  Continuous instructions and reminders  Loading gently scaled, accommodative  Unloading abrupt, snap like  Tether strap held in free hand, on slack  Resist impulse to prevent fall response  Step toward client during unloading 54

55. RIPPS: Troubleshooting Technique Notes  Poorly defined multiple steps (>3)= F  2 nd chance loading accommodation  Contact with support surface = F  Loading: empty end feel-keep pulling!  Modify distance from support surface in cases of  apprehension and or frailty 55

56. RIPPS: Restrictions RIPPS not advised in presence of:  Acute orthopedic “healing” issues  Acute surgical “healing” issues  Unstable medical conditions  Painful lower limb bearing issues  Disproportionate anxiety 56

57. RIPPS: Scale calibration 57 Known weight (5lbs) attached to scale suspended in vertical orientation. Scale measurement should equal known weight. Calibration achieved via adjustable locking turn knob mechanism feature.

58. 58 BREAK

59. RIPPS: Evidence Spring Scale Test: SST Results Reliability, Discriminant Validity Fallers vs Non-fallers 59

60. 60 RIPPS Evidence: SST Data Analysis  Age, fall status & other fall related variables.  Reliability: Test re-test ICC, Method error (ME) and Coefficient of variation (CV).  Validity: Convergent via Pearson point-biserial analysis. Discriminant via logistic linear regression / odds ratio and ROC/AUC analysis.

61. 61 RIPPS: SST Evidence Results Mean % TBW, Reliability  Mean SST % TBW: fallers 7.5% +/-1.4% 95% CI (6.1 - 8.9) p=.000.  Non-fallers 12.3% +/- 1.7% 95% CI (10.6 - 14)p=.000.  ICC.94 single and.97 average.  Method error (ME).74 < 1 lb: (1lb=real change); calibration= 1 lb.

62. 62 RIPPS: SST 10% Evidence Results Discriminant Validity  Coefficient of variation (CV) real change 7.25%. (1 lb. ‹135 lb. / 2 lbs.  135 lb.)  AUC =.992, sensitivity = 93.1% specificity = 96.6%.  + PV = 96.4% and – PV 93.3%.  Odds ratio = 700245.7. (Portney, Watkins. Foundations of clinical research: applications to practice 2 nd ed 2000, Prentice Hall)

63. Table 2. Comparison of Measurements Obtained from 58 Older Adults Classified as Fallers (n=29) or Non-fallers (n=29) VariableFallerMe an±S Non-fall Mean±S T-test T (p) ROC Results** Area Under Curve Cut Point Sensitivity/ Specificity (%) Age (yr)83.5±5.578.0±7.8-3.18 (.003).694 80 75.9 / 51.7 SST (% weight)*7.5±1.412.3±1.711.63 (.000).992 10.093.1 / 96.6 Gait speed (m/s)1.0±.21.3±.24.623 (.000).820 1.265.5 / 75.9 Timed Up & Go (s)9.2±1.37.0±.9-7.22 (.000).916 7.479.3 / 93.1 Single limb stance (s)3.2±3.310.3±9.63.78 (.001).766 6.548.3 / 89.7 Tandem stance (s)12.7±10.823.9±9.94.12 (.000).765 22.072.4 / 75.9 Physical functioning (%) 63.3±18.686.3±12.25.56 (.000).850 77.572.4 / 79.3 *% TBW **ROC = Receiver operating characteristic curve 63

64. Table 1. Pearson Correlations (Probabilities) Between Variables Predicting Falls AgeSST%GSTUGSLSTS SST%-.471 (.000) Gait speed (GS)-.389 (.003).532 (.000) Timed Up & Go (TUG).399 (.002) -.671 (.000) -.513 (.000) Single limb stance (SLS) -.582 (.000).539 (.000).340 (.009) -.477 (.000) Tandem stance (TS) -.355 (.006).552 (.000).364 (.005) -.458 (.000).498 (.000) Physical functioning (PF) -.400 (.002).623 (.000).746 (.000) -.696 (.000).416 (.001).406 (.002) 64

65. 65 SST 10% TBW AUC TUGT 7.4 sec AUC (79.3 sens) RIPPS: ROC Area Under the Curve (AUC)

66. 66 RIPPS: SST Evidence Sensitivity, Specificity SST 10%/ GS 1.2/ TUG 7.4/ SLS 6.5/ TS 22 TUGT ceiling effects evident at high performance levels

67. RIPPS: SST Evidence Balance-Related Measures  TUGT: fallers; 28/29 (97%) within norm published decade specific 95% CI (Bohannon, JGPT’09). 26  SLST: correctly ID fallers 35%; non- fallers falsely ID 38% based on published 95% CI (Bohannon, Top Ger Rehab’06). 27 67

68. RIPPS: SST Evidence Balance-Related Measures  TST: 10 sec. Cutoff failed to ID 52% fallers; false + ID 14% non-fallers. (Guralnik, 2000). 28  Gait speed: mean vel. >1.0m/sec for both groups significant for community walking (Fritz, Lusardi JGPT’ 09). 29 68

69. RIPPS: SST 10% Evidence Summary  Reliable ICC.94/.97.  Most discriminant ROC (AUC=.992) compared to available alternatives.  Efficient tool supported by logistic regression. 69

70. RIPPS: Stepping Applications Threshold and Direction Limits Stepping 70

71. RIPPS: SST Evidence (n=58) Directional Threshold Steps 71 N AFANFPFPNF Rear Stepping Forward Stepping Fallers exhibit higher frequency multiple steps Fallers exhibit  threshold steps

72. Threshold: Mean Percent Body Weight Fallers vs Non-fallers 72 % Non-faller threshold % values approximate 50% m DL %

73. RIPPS Threshold Application  Fallers: lower % TBW threshold  Fallers: multiple step threshold responses (>50%)  RIPPS intervention goal:  threshold % TBW force and  # steps 73

74. RIPPS: SST Evidence (n=58) Limit (DL) % TBW : Decade 74

75. RIPPS: SST Evidence DL Step Responses 75 N Rear Stepping Forward Stepping Fallers:  stepping frequency

76. Mean Limit % Body Weight: Fallers vs Non-fallers (n=58) 76 % 10 % TBW achieved by all decades

77. RIPPS: % TBW Limit Non- faller Frequency (n=29) 77

78. RIPPS: Faller % TBW Limit Frequency (n=29) 78

79. RIPPS: SST Evidence Step Responses in Old and Young  5% TBW:UI (un-impaired) 1.14f/1.60r steps vs BI (balance impaired) 1.63f/2.11r steps. (Schultz,’05). 21  SST: NF:1.43r/1.45f, F: 2.41r/2.17f  Of note: Young adults: 10% TBW (avg. thresh) 1.07/1.0(r/f). (Unpub. IRB study).  SST results in agreement with lab-based random method study by Schultz. 79

80. RIPPS: Stepping Significance  Multi-step responses are not innocuous.  Each additional step is destabilizing presenting additional opportunity for adverse responses, increasing fall risk. (Maki B, et al. J Gerontol A Bio Sci Med Sci. 2000). 42 80

81. RIPPS: Stepping Significance  Altered stepping may be viewed as an emergent feature of multiple impairments associated with falls. (Hanke, JGPT, 2006). 40  Aging affects stepping responses.  Following perturbation training a reduction of 0.5 steps will have functional significance. (Mansfield A, BMC Ger. 2007). 41 81

82. RIPPS: Application DL Stepping RIPPS goals:  number DL steps  DL % TBW  DL step length 82

83. Non-fallers Fallers  Anticipatory   anxiety, efficient strategy shift  Smooth, proportional scaling accommodation (loading)  Fewer, well defined steps   5% TBW threshold  12.3% DL mean  Reactive   anxiety, inefficient   Hip strategy,  UE  Disproportionate scaling  Multiple shorter, poorly defined steps  low threshold % TBW  7.5% DL mean 83

84. RIPPS: 10 % TBW Stepping Responses Clinical Significance Evidence 84

85. RIPPS 10% TBW Step Responses: Fallers vs Non-fallers 85 3 1-2 step response common at 10% TBW [Younger adults exhibit threshold at 10% TBW] STEPS N

86. RIPPS: 10% TBW Non-faller Responses  Anticipatory, well – defined 1-2 steps  Anticipatory, min-reactive, low anxiety  Should not be DL value (reserve)  Report subjective significant effort 86

87. RIPPS: SST Evidence 10% TBW Discussion  Valid and reliable.  Most discriminant to fall history.  Excellent positive and negative predictive values for ID fall status.  Sensitivity (snout) and specificity (spin) > 90% useful as a diagnostic tool. 87

88. RIPPS Applications: Functional mobility correlates  RIPPS 10% DL : ID stepping reserve deficits requiring intervention. (no device)  RIPPS scores 8.5 (FOF); restricted, familiar environment community integration with cane.  < 8.0%; walker @ level 6 or cane level 4/5 assist. (further study). 88

89. RIPPS: SST Evidence 10% TBW Discussion  Efficient ID fall status in active older persons with less pronounced deficits.  Applications in both wellness and impaired populations.  Assessment and treatment application.  Early detection of ‘concealed’ deficits.  Appropriate for various clinical settings 89

90. RIPPS: SST Evidence Supports  Single clinician administration.  RIPPS foundations: repeated, incremental, predictable perturbations.  Cyclic rounds loading/unloading 1 lb. incremental waist pull forces.  Criteria: loading accommodation unloading 3 step limit. 90

91. RIPPS: SST Evidence Summary  Quantifies stepping balance domain, not currently in clinical use. (Mansfield). 14  Percent of total body weight (% TBW) as a quantitative balance “measuring stick” 91

92. RIPPS: Foundations Integrating Current Evidence: Neurophysiology, Aging Postural Control Motor learning 92

93. RIPPS Foundation: Aging Neuromuscular changes  Selective atrophy type II ftm fibers.   number of muscle fibers & spinal cord axons. 1/3  muscle mass by age 80.   reaction time,  latency,  response amplitude,  NCV. Later motor fiber loss  Selective loss in anatomical structure and physiologic function of large A  myelinated fibers (spindles, GTO, joint afferents, proprioceptor/kinethesia).  Vestibular hair cell loss 93

94. RIPPS Foundation: Aging Postural Control   recruitment and recovery from external perturbations.  co- contraction  Slower initiation and termination reaction times   sensori-motor function  postural stability (Tucker M, et al. J Mot Behav. 2010). 32 94

95. RIPPS Neurophysiology: Scaling  Scaling of automatic postural responses occurs in direct proportion to the magnitude of the imposed disequilibrium utilizing anticipatory predictive mechanisms based upon prior experience. (Horak, PTJ, 1997). 38  Scaling is based on both the direct sensory characteristics such as initial perturbation speed and anticipatory mechanisms. 95

96. RIPPS Foundation: Single Trial First Trial Reactions (Oude L, et al. J Neurophys, 2009). 30  Does inclusion of first trial reactions add extra information in discriminating between normal and balance impaired individuals?  Message: FTR’s are significant within a predictable context incorporating SINGLE TRIAL format. 96

97. RIPPS Foundation: Single Trial First Trial Response FTR (Allum J, et al. Hum Mov Sci. 2011). 31  FTRs associated with  trunk flexion, exaggerated postural responses  Associated with postural instability  Vestibular modulating, no trigger role  Proprioceptive triggering, [unresolved]  Link between FTRs and balance? RIPPS first trial performance criteria 97

98. RIPPS: Neurophysiology: Proactive - Reactive Control  Proactive and reactive responses play key role in dynamic standing balance control via feed forward control to continuously update internal model of COM stability region (Pai, Jl. Neurophys, 2003). 33 98

99. RIPPS Neurophysiology: Reactive Proactive  May be dominant in avoiding a fall when perturbations are less certain. Pavol 34  Reactive stepping has a critical importance in fall prevention. Pai 33   reliance on reactive response in uncertain conditions. Pavol 34   stability with a  reliance on reactive responses. Pai 22 99

100. RIPPS Neurophysiology: Reactive Proactive  Generated via sensorimotor feedback (VISION) unpredictable.  Can modify behavior in progress, automatic (trip) or volitional step. (Tseng et al. Jl Gerontolol A Biol Sci Med Sci 2009). 35  Based on a feed- forward movement plan, predictable.  Highly effective when perturbation direction is foreseeable. Pai 33 100

101. RIPPS Neurophysiology: Reactive Proactive  Second line of defense. Pai 33  Distal to proximal temporal / spatial sequence.  Distal responses with  latencies and longer burst durations vs  proximal muscle group latency. (Tang, Woolacott, Exp. Brain Res., 1998). 36  First line of defense against falling.   reliance on reactive feedback control with repeated perturbations. Pai 33 101

102. RIPPS: Neurophysiology: adaptive control  Repeated exposure to perturbations results in the emergence of newly acquired predictive adaptive control.  CNS refines or updates an internal representation of the potential threats that may occur in the external environment. Pai 22 102

103. RIPPS: Reactive Proactive  RIPPS anticipatory biased method seeks to optimize feedforward, anticipatory responses.  Persistent RIPPS - induced reactive response dominance could be indicative of deficits related to predictive adaptation and COM stability updating.  RIPPS employs reactive and proactive elements of motor control. 103

104. RIPPS Neurophysiology: Cortical Control; perturbations  Perturbation response quicker than fastest voluntary movement.  Long latency postural responses: direct cortical influence via corticospinal loops.  Shorter latency indirect: via communication w brainstem synergies centers. (Jacobs J, Horak F,J Neural tansm. 2007). 43 104

105. RIPPS Neurophysiology: Cortical control  Cortical: Changing responses via central set modifications based upon prior experience, warning, context.  Cerebellar-cortical: Adapting responses based on prior experience.  Basal ganglia-cortical: Preselection and optimizing responses based upon current context. 43 [RIPPS engages these elements of control] 105

106. RIPPS Neurophysiology: Supplementary motor area (SMA)  SMA may contribute to timing of anticipatory postural adjustments  Motor cortex or basal ganglia may modulate amplitude (Jacobs J, et al. (Neuroscience 2009). 44 [RIPPS predictable, anticipatory format seems compatible SMA] 106

107. RIPPS: Neurophysiology: Cortical control  Cortical circuit activation may modify postural responses only where balance loss is anticipated.  Movements once considered automatic may be under cortical influence thus enabling voluntary cortical access to automated postural responses (Jacobs J, et al. Clin Neurophys. 2008). 45 [Cortical activation augmented with RIPPS anticipatory biased format] 107

108. RIPPS Neurophysiology Stepping postural responses  Functional muscle synergies that produce forces to restore CoM position in non stepping responses are also used to displace the CoM during stepping.  Muscle synergies may reflect spinal and brain stem structures mediating motor control across a variety of behaviors and contexts. (Stacie A, et al. J Neurophys. 2011). 46 [RIPPS employs both non-stepping and stepping responses] 108

109. RIPPS: Neurophysiology Voluntary vs Induced Stepping Reactive voluntary time stepping: 1.waist pull perturbation 2.SOM waist tug 3.audible cue  Perturbation training resulted in greater IT improvement vs AUD transfer cue task.  Repeated application of stimuli could enhance the synaptic effectiveness of step pathways in common neural circuits with voluntary stepping. (Rogers,Jl Gerontol’03). 19 109

110. RIPPS Neurophysiology: Voluntary stepping  Compensatory stepping reactions differ fundamentally from voluntary stepping. (McIlroy, et al. Brain Res ’93). 39  Voluntary training might be useful to train postural responses. (Jacobs J, et al. Clin Neurophys. 2008). 4 [Could be adjunct to RIPPS] 110

111. RIPPS Neurophysiology: Plasticity - Peri Infarct Cortex  Structural changes include axonal sprouting, dendritic remodeling, synapse formation (animal studies).  Early intervention for exploitation of spontaneous occurring plasticity (PIC)  Reorganization possible > 6 months post CVA (Hosp J, Luft A, Neural Plasticity 2011). 47 Good news! 111

112. RIPPS Foundation: Motor Learning; retention Good news!  Older adults can rapidly develop adaptive skills for fall prevention similar to young adults after exposure to repeated perturbations. Pai 22  General postural motor learning, regardless of the mechanism, in healthy older adults, does not change with age. (Van Ooteghem, 2010 Exp Br Res). 37 112

113. RIPPS: Neurophysiology Motor learning: Mental practice (MP)  MP: activation of same neuromuscular structures involved with actual physical practice of same task.  30 min. task specific practice (RTP) followed by 20 min MP: changes observed without intensive practice, efficient.  MP with RTP appears to result in cortical reorganization. (Page S, et al. Neurorehab Neuro Repair. 2009). 48 Underutilized modality? 113

114. RIPPS Neurophysiology: Retention  Single acquisition sessions with highly threatening environment could induce long term retention of acquired motor behavior. Pai 22  Trial sequence for acquisition session NS/NS/NS/NS SSSSS NS/NS/NS SS S: First slip unannounced followed by warning that slip might occur. 13 Modifiable for RIPPS at sub and supra stepping threshold forces. 114

115. RIPPS Neurophysiology Motor learning  Perturbation-based training combined with power/high-velocity resistance training may have the potential to improve neuromuscular capacities for balance - threatening conditions. (Granacher U, et al. Sports med. 2011). 49 [RIPPS specificity for induced stepping] 115

116. RIPPS Neurophysiology: Motor learning External focus of attention results in more effective motor learning and greater automaticity. External focus of attention enhances balance learning in older adults. (Chiviacowsky S, et al. Gait Posture. 2010). [Example: Avoid contact with support surface] 116

117. RIPPS: Applications Intervention; Goals; Options  Non-stepping mode :  foot flat accommodation % TBW force limit.  Induced stepping mode:  threshold stepping force  DLT steps required  DLT % TBW force.  Trial blocks : step/non-step Borg RPE monitored.  Verbal instruction, goal manipulation 117

118. RIPPS Applications: Retention  Goal:  10% TBW directional limit scores, anterior and posterior.  Retention observed for 3 consecutive sessions for  2 week interval. (personal experience, further study). 118

119. RIPPS Applications: Outside the Box Ideas  Lateral stepping RIPPS % TBW (dominant foot in rear heel step stance)   Non stepping limits via ankle / hip  Seated RIPPS for trunk control via continuous or load / unload methods  > 1lb intervals for reactive effect  Protracted quasi-random 5s window 119

120. RIPPS: Lateral Stepping  Multiple stepping for ML balance recovery associated with ID future fall risk. (Hilliard M, et al. Arch Phys med Rehab. 2008). 51  Young: single step response with original loaded limb  Older: Crossover step preference with multiple steps and limb collisions  Hip abduction torque - time capacity deficits could be associated with lateral balance control issues in elderly. (Mille M, et al. Clin Biomech. 2005). 52 120

121. Questions ? BREAK 121

122. RIPPS: Case Presentations Comparisons Interpretations Clinical Performance Measures 122

123. RIPPS: (71) Vertigo, COPD, MG  Gait speed: 1.0 m/sec  TUGT 10 sec  Tinetti 28  FR 12 inches  RIPPS: 9.8a/5.5p  Impression? 123

124. RIPPS: (80) OA Knees  Gait speed:.90 m/sec  TUGT: 12.5 sec  Tinetti: 24  4SST: 10.6 sec  360 turn: 3 sec. FR 11 inches  RIPPS: 3.7t:8.6DL/2t:8.0DL (t=thresh/DL=limit)  Impression: Transitional boarder line? 124

125. RIPPS: (93)Cx.Sp.Fx, Syncope  Gait speed:.70m/sec  TUGT 10.3 sec  Tinetti 25  4SST: 15 sec  RIPPS: 4.8a/11.7p  GS and RIPPS concur 125

126. RIPPS: Cancer/Chemotherapy  Gait speed: 1.0  TUGT 8.4 sec.  5XSST: 10 sec.  Tinetti 28  FR: 11 inches  RIPPS: 11a/10.9p Impression ? 126

127. RIPPS: (90) Hip HA  Gait speed: 1.15m/sec  TUGT: 8 sec  4SST: 10.5 sec  Tinetti: 28  RIPPS: 8a/11.1p FTR apprehension  Impression? Too fast for own good? 127

128. RIPPS: (75) CVA  Gait speed: 1.02 m/sec  TUGT: 9.3 sec  Tinetti: 25  360 turn: 3 sec  RIPPS: 8.3a/12p Impression? 128

129. RIPPS: (85) vaso-vagal Syn.  Gait speed: 1.28 m/sec  TUGT: 9 sec.  5XSST: 10.9 sec  FR: 12 inches  Tinetti: 28  RIPPS: 10.7a/12/1p  % TBW : 8.5 11.1 9.3 10.7 (4 visits). Retention? 129

130. RIPPS: (94) OA Knee  Gait speed: 1.04 m/sec  TUGT 9.5 sec.  Tinetti 28  4SST: 11.9 sec  RIPPS: 8.5a/11.5p  Impression (cane/car 1 yr later) 130

131. RIPPS: (75) COPD, RA  Gait Speed: 1.0 m/sec  TUGT: 9.8 sec  Tinetti: 25  5XSST: 10 sec  RIPPS: 11.1a/11.1p  Impression? 131

132. RIPPS: % TBW Training Perturbation Exercise Quantifying Force: RIPPS % TBW 132

133. Force Elongation Chart: Modified @ 100 % Elongation  YELLOW = 3 pounds (2.9)  RED = 4 pounds (3.9)  GREEN = 5 pounds  BLUE = 7 pounds  BLACK = 10 pounds (9.7)  SILVER = 13 pounds (13.2) Page, et al. JOSPT 2000; 30(1):A47. 53 133

134. RIPPS: Bed Pull System  Web strap length adjusted to bed width less 1 foot  1-foot tubing length connected to strap and to 2-inch wide nylon waist belt (user not in photo) 134

135. RIPPS: Perturbation Home Program Bed Pull System  PVC T anchor  Adjustable length web strap  Tubing in 1-foot lengths  2-inch nylon belt  Snap hook and D/O rings 135

136. RIPPS: Bed Pull Anchor  PVC T anchor stabilized between mattress and box spring  Adjustable web strap secured to PVC T anchor 136

137. RIPPS: Determining Force  Normal resting length = 1 foot  Tubing mid point ID  Tubing color(s) 100% force / elongation chart 137 Nylon webbing check strap

138. RIPPS: 100% Elongation  1 ft length @ 100% elongation = 2 feet  User/bed distance 1 foot (safe) @ 100 % elongation 138 Nylon webbing check strap

139. RIPPS: Bed Pull Perturbation  Mono / multi-color combinations, multiple tubing strands. Check strap (breakage)  Combined tubing force should = RIPPS % TBW direction limit value  User to bed distance = 1 foot during training session maintaining 100% elongation  Waist belt slip O ring allows user freedom of movement any direction during use 139

140. RIPPS: Perturbation Training Advantages  Safety  Quantification  Compliance  Goal driven  Specificity training  Documentation 140

141. RIPPS: Bed Pull Perturbation Treatment Strategies  Feet in-place: ankle/hip LOS tasks  Stepping: Alternate uni / rhythmic cyclic  Stepping: AP/ML/Diagonal  Lunge patterns, reaching, 360 turns  Terminal hold  Dual tasking, EO EC, foam 141

142. Alternate Exercise Ideas Auto Perturbation Tasks Ankle Strengthening SOT 142

143. Balance Exercise Ideas  Ankle strengthening / stretching  Compliant Surface: DBA tasks  MSL tasks (SL:LEL)  Four Square Step Test  SOT #6? 143

144. Ankle Ideas  PVC T DESIGN  Resisted PF/DF  PF Stretching  Maximizes short lever mechanics  Swifter/sponge mop seated 144

145. Auto Perturbation Options: Compliant Surface Task  SHAPES/DENSITIES  Incline Orientation  SLOW/FAST AP  ANKLE STRATEGY  CANE/BROOMSTICK  DIAMETERS/HEEL HT 145

146. Cylinder Ankle Rock Tasks  SOLID/FOAM OR  FOAM OVERLAY  DIAMETER SIZES  ANKLE/HIP/STEP  Terminal holding  Pro/Re ACTIVE  Speed 146

147. Lateral Stepping MSL (Cho B,Tests of Stepping.. Mobility, Balance, Fall Risk BI Older Adults. JAGS. 2004). 55  MSL STUDY  MAX STEP LENGTH  SPEED  LENGTH  AGILTY  TEMPO  MEASUREABLE  SL: LEL vs MSL? 147

148. 4 Square Step Test (FSST) Dite W., A Clinical Test of Stepping…..ID Multiple Falling Older Adults. Arch Phys Med Rehab. 2002. 55  1-4  4-1 ROUTE  NO TURNS  Same orientation  2 FEET EACH BOX  CLEAR OBSTACLE  12/15 SEC CUT OFF 148

149. RIPPS: Future Study  Induced stepping treatment paradigm, responsiveness, retention  Duplication of RIPPS SST results  Lateral perturbation step testing  Prospective or Retro study design?  Predictable vs random (reactive) perturbation methods  RIPPS vs instrument-based tests 149

150. RIPPS: Conclusion Why wait for a fall ?  Responsive balance tests to ID mild levels of balance impairment could ID people who, without intervention, would likely progress to becoming a “faller”. (Yang XJ, et al. PTJ. 2012). 58 150

151. RIPPS: Conclusion Why wait for a fall ?  Intervention introduced when balance dysfunction has recently developed or is of a mild level of severity may be most efficacious than implementing interventions when a fall has occurred. (Herman C, et al. AJR. 2002). 59 151

152. RIPPS: Final thought If……………… a prior fall is the best predictor of a future fall….. and if…. a non-faller is ID as a ‘faller’ by a fall assessment tool highly discriminant to known fallers, then…………….. in effect……. has a ‘fall’ occurred? 152

153. RIPTS: Repeated Incremental Peeling Tomatoes (mom, 2013)  Questions  Discussion  Further study  Ideas  Innovation 153 Peeling in the years

154. Spring at Cold Spring “You can’t follow all your dreams….you might.....…get…..lost”….. Always be……….. “working on a dream”…. From……. “a day dream believer”…. “long may you run”! ( borrowed lyrics ) 154

155. References 155 1.Harris JE, et al. Relationship of balance and mobility to fall incidence in people with chronic stroke. Phys Ther. 2005; 85: 150-158. 2.Verghese J, et al. Epidemiology of gait disorders in community-residing older adults. J Am Geriatr Soc. 2006; 54(2): 255-61. 3.Moyer V, Prevention of falls in community-dwelling older adults: U.S. preventive services task force recommendation statement. Ann of Intern Med 2012; 157(3). 4.Renfro MO, Fehrer S. Multifactorial screening for fall risk in community- dwelling older Adults in the primary care office: development of the fall risk & screening tool. JGPT. 2011; 34: 1-10

156. References 156 5. Mangione K, Palombaro K. Exercise prescription for a patient 3 months after hip fracture. Phys Ther. 2005 Jul; 85 676-87. 6.Boulgarides LK, McGinty SM, Willett JA, Barnes CW. Use of clinical and impairment-based tests to predict falls by community-dwelling older adults. Phys Ther. 2003; 83: 328-339. 7.Lin S, Woollacott M. Association between sensorimotor function and functional and reactive balance control in the elderly. Age and Aging. 2005; 34:358-63. 8. Muir S, Berg C, et al. Balance impairment as a risk factor for falls in community-dwelling older adults who are high functioning; a prospective study. Phys Ther. 2010; 90(30: 338-47.

157. References 157 9. Lin MR, Hwang HF. Et al. Psychometric comparisons of the timed “up and go”, one-leg stand, functional reach and Tinetti balance measures in community- dwelling older people. J Am Geriatr Soc. 2004; 52: 1343-1348. 10. Buatois S, et al. A simple clinical scale to stratify risk of recurrent-falls in community-dwelling adults 65 years and older. Phys Ther. 2010; 90(4): 550-60. 11. Neuls P, et al. Usefulness of the Berg Balance Scale to predict falls in the elderly. Jl Geriatr Phys Ther. 2011; 34(1): 3-10. 12. Pardasaney PK. Latham NK, Jette AM et al. Sensitivity to change and responsiveness of four balance measures for community-dwelling older adults. Phys Ther. 2012; 92: 1-10.

158. References 158 13. Pai YC, Wang E, Espy D, Bhatt T. Adaptability to perturbation as a predictor of future falls: A prelim. prospective study. J Geriatr Phys Ther. 2010; 33(2) 50-61. 14. Mansfield A, et al. Training rapid stepping responses in an individual with stroke. Phys Ther. 2011; 91(6): 958-69. 15. Wolfson LI, Whipple R, et al. Stressing the posture response: a quantitative method for testing balance. J Am Geriatr Soc. 1986; 34: 845-850. 16. Lee W, Deming L, Sahgal V. Quantitative and clinical measures of static standing balance in hemiparetic and normal subjects. Phys Ther. 1988; 68(6): 970-76.

159. References 159 17. Chandler J, Duncan P, Studenski S. Balance performance on the postural stress test: comparison of young adults, healthy elderly and fallers. Phys Ther. 1990; 70(7): 410-415. 18. Luchies C, et al. Stepping responses of young and old adults to postural disturbances: kinematics. J Am Geriatr Soc. 1194; 42(5): 506-12. 19. Rogers M, et al. Step training improves the speed of voluntary step initiation in aging. Jl Gerontol. 2003; 58a(1): 46-51. 20. Jöbges M, Heuschkel G, et al. Repetitive training of compensatory steps: a therapeutic approach for postural instability in Parkinson’s didease. J Neurosurg Psychiatry Neurol. 2004; 75: 1682-87.

160. References 160 21. Schultz BW, Ashton-Miller JA, et al. Compensatory stepping in response to waist pulls in balance-impaired and unimpaired women. Gait Posture. 2005; 22: 198-209. 22. Pai YC, Bhatt TS. Repeated-slip training: an emerging paradigm for prevention of slip-related falls among older adults. Phys Ther. 2007; 87: 1-13. 23 DePasquale L, Toscano L. The spring scale test (sst): a reliable and valid tool for explaining fall history JGPT. 2009; 32(4): 159-67. 24. Mansfield A, Peters AL, et al. A perturbation-based balance training program on compensatory stepping and grasping reactions in older adults: A randomized controlled trial. Phys Ther. 2010; 90: 476-89.

161. References 161 25. Portney L, Watkins M. Foundations of clinical research: applications to practice. Prentice Hall Health. 2nd ed. 2000. Validity of measurements. Chapter 6; p 95. 26. Bohannon R. Reference values for the timed up and go test: A descriptive meta- analysis. Jl Geriatr Phys Ther. 2009; 29(2): 64-68. 27. Bohannon R. Single limb stance times: A descriptive meta-analysis of data from individuals at least 60 years of age. Top Geriatr Rehab. 2006; 22(1): 70-77. 28. Guralnik JM, Ferricci L, Pieper CF et al. Lower extremity function and subsequent disability: Consistency across studies, predictive models, and value of gait speed alone compared with the short physical performance battery. J Gerontol A Biol Sci Med Sci. 2000; 55: M221-M231.

162. References 162 29. Fritz S, Lusardi M. White paper: “Walking speed: The sixth vital sign.” Jl Geriatr Phys Ther. 2009;32(2): 2-4. 30. Oude L, et al. Directional sensitivity of “first trial” reactions in human balance control. J Neurophsiol. 2009; 101: 2802- 2814. 31. Allum J et al. Review of first trial responses in balance control: influence of vestibular loss and parkinson’s disease. Hum Mov Sci. 2011; 30(2): 279- 95. 32. Tucker M, et al. Differences in rapid initiation and termination of voluntary postural sway associated with aging and falls risk. J Mot Behav. 2010;42(5): 277- 87.

163. References 163 33. Pai YC, Wening JD, Runtz EF, Iqbal K, Pavol MJ. Role of feedforward control of movement stability in reducing slip- related balance loss and falls among older adults. J Neurophysiol.2003; 90: 755-762. 34. Pavol MJ, Pai YC. Feedforward adaptations are used to compensate for a potential loss of balance. Exp Brain Res. 2002; 145: 528-538. 35. Tseng S, et al., Impaired reactive stepping adjustments in older adults. J Gerontol A Bio Sci Med Sci. 2009; 64a: (7) 807-15. 36. Tang P, Woolacott M, Chong K. Control of reactive balance adjustments in perturbed human walking: Roles of proximal and distal postural muscle activity. Exp Brain Res. 1998; 119: 141- 52.

164. References 164 37. Van Ooteghem K, et al. Healthy older adults demonstrate generalized postural motor learning in response to variable amplitude oscillations of the support surface. Exp Brain res. 2010; 204(4): 505-14. 38. Horak F, et al. Postural perturbations; new insights for treatment of balance disorders. Phys Ther. 1997; 77(5): 517- 33. 39. McIlroy W, Maki B. Task constraints on foot movement and the incidence of compensatory stepping following perturbation of upright stance. Brain Res. 1993; 616: 30-38. 40. Hanke T, Tiberio D. Lateral rhythmic unipedal stepping in younger, middle- aged and older adults. JL Geriatr Phys Ther 2005; 29: 20-25.

165. References 165 41. Mansfield A, et al. A perturbation-based balance training program for older adults: study protocol for a RCT. BMC Geriatrics. 2007; 7(12) 14 pages. 42. Maki B, et al Age-related differences in laterally directed compensatory stepping behavior. J Gerontol A Bio Sci Med Sci. 2000; 55: M270-77. 43. Jacobs J, Horak F. Cortical control of postural responses. J Neural transm. 2007; 114(10) 1339-48. 44. Jacobs J, et al. The supplementary motor area contributes to the timing of the anticipatory postural adjustment during step initiation in participants with and without Parkinson’s disease. Neuroscience. 2009; 164(8): 877-85.

166. References 166 45. Jacobs J, et al. Changes in the activity of the cerebral cortex relate to postural response modification when warned of a perturbation. Clin Neurophysiol. 2008; 119(6): 1431-42. 46. Stacie A, et al. Common muscle synergies for control of center of mass and force in nonstepping and stepping postural behaviors. 2011; J Neurophysiol. 106: 999-1015. 47. Page S, et al. Cortical plasticity following motor skill learning during mental practice in stroke. Neurologic Neural Repair. 2009; 23(4): 382-88. 48. Hosp J, Luft A. Cortical plasticity during motor learning and recovery after ischemic stroke. Neural Plasticity. 2011; doi: 10.1155/2011/871296: 9 pages.

167. References 167 49. Grenacher U, et al. Comparison of traditional and recent approaches in the promotion of balance and strength in older adults. Sports Med. 2011; 41(5): 377-400. 50. Chiviacowsky S, et al. An external focus of attention enhances balance learning in older adults. Gait Posture. 201;32(4): 572-75. 51. Hilliard MJ, et al. Lateral balance factors predict future falls in community-living older adults. Arch Phys Med Rehab. 2008; 89(9): 1708-13. 52. Mille M, it al. Age-dependent differences in lateral balance recovery through protective stepping. Clin Biomech. 2005; 20(6): 607-16. 53. Page P, et al. JOSPT. 2000; 30(1) A 47

168. References 168 54. Cho B, et al. tests of stepping as indicators of mobility, balance and fall risk in balance-impaired older adults. JAGS.2004; 52: 1168-73. 55. Dite W, et al. A clinical test of stepping and change of direction to identify multiple falling older adults. Arch Phys Med Rehab. 2002; 83: 1566-71. 56. Desai A, et al. Relationship between dynamic balance measures and functional performance in community- dwelling elderly. Phys Ther. 2010; 90(5): 748-60. 57. Buatois S, et al. Posturography and risk of recurrent falls in healthy non- institutionalized persons aged over 65. Gerontology. 2006; 52: 345-52.

169. References 169 58. Yang XJ, et al. Effectiveness of a targeted exercise intervention in reversing older people’s mild balance dysfunction: a RCT. Phys Ther. 2012; 92(1): 24-37 59. Herman C, et al. Screening for pre- clinical disease: test and disease characteristics. AJR Am J Roentgenol. 2002; 179: 825-31.