Geriatric Gait

Definition & Stages of Frailty

• Three-stage continuum
  • Pre-frail → Frail → Frail with complications (complex, multidimensional impairment)
• Common patient comment/example: speaker moved to Houston, heat + inactivity → felt “frail”; illustrates reversibility with intervention

Phenotypic Criteria for Frailty (Fried et al.)

• Meet $\ge 3$ of 5 items → classified as frail; $1\text{–}2$ items → pre-frail
  • Unintentional weight loss
  • Self-reported exhaustion / poor endurance
  • Weak grip force (proxy for global weakness)
  • Slow walking speed (>$>6\text{–}7\text{ s}$to cover$15\text{ ft})
  • Low physical activity (sex-specific cut-offs)

Biological Cycle of Frailty

• Aging, malnutrition, disease, environmental stressors → undernutrition
• Undernutrition drives inflammation, coagulation deficits, hormonal dysregulation
• Leads to sarcopenia & muscle weakness →
  • \uparrow$insulin resistance</li> <li>$\downarrow\text{VO}_2\text{ max}$</li> <li>$\downarrow strength, power, gait speed, PA level, total EE
• Vicious cycle perpetuates progressive frailty unless interrupted (e.g., PT, active community)

“Slippery Slope” Model of Aging

• Axes: Time (x) vs. Physical/Cognitive/Social Function (y)
• Bands:
  • Successful Agers: high reserves, active, volunteering/gardening, emotional–social–spiritual engagement (salutogenic factors)
  • Frail: mid-level, at risk for rapid decline
  • Dependent/Complicated Frail: ADL loss
• Rapid downward curves once reserve is lost—highlights urgency of early intervention

Falls & Fear of Falling (FOF)

• Quality-of-life cascade: FOF → reduced PA → deconditioning → higher instability → more falls
• Personal example: tile floors in flood-prone Houston triggered thoughts about fall consequences

Intrinsic Risk Factors

• Cannot SLS >5\text{ s}$</li> <li>Requires UE push to rise from chair</li> <li>LE weakness (esp. proximal, knee)</li> <li>Balance/gait impairments</li> <li>Use of assistive device (cane users$\approx 2\times$risk)</li> <li>Hx of falls or FOF</li> <li>Slow TUG, weak knee, proprioceptive loss (diabetes, post-stroke), female sex, antidepressant use</li> </ul> <h5 id="extrinsicenvironmentalriskfactors">Extrinsic / Environmental Risk Factors</h5> <ul> <li>Multiple meds ($\ge4$or psychoactive)</li> <li>Crowded, noisy, cluttered spaces; animals</li> <li>Slippery surfaces, poor lighting, throw rugs, uneven sidewalks, stairs w/o rails</li> </ul> <h5 id="greatestrelativeriskstop6">Greatest Relative Risks (top 6)</h5> <ol> <li>Previous fall</li> <li>Balance impairment</li> <li>Muscle weakness</li> <li>Vision impairment</li> <li>$>4$meds / psychoactives</li> <li>Reported gait impairment</li> </ol> <h4 id="fallriskclinicalalgorithmags2017">Fall-Risk Clinical Algorithm (AGS 2017)</h4> <ol> <li>Screen ALL adults$\ge65$y (or younger but sedentary/frail-appearing)</li> <li>Ask: “Have you fallen in the past year?”<ul> <li>$\ge2 falls or any fall with injury ⇒ high risk

Self-Report Measures

• FES-I (Falls Efficacy Scale-International)
• Geriatric Depression Scale (GDS) – both correlate with fall risk

Performance Measures & Cut-offs

• Single-Limb Stance <6\text{ s}
• Self-selected gait speed <1\,\text{m}\,\text{s}^{-1}
• Berg Balance Scale <50
• TUG >11\text{ s}
• 5× Sit-to-Stand >12\text{ s}$</li> </ul> <h4 id="gaitparametersacrossrobustfrailcontinuum">Gait Parameters Across Robust→Frail Continuum</h4> <ul> <li>Data via GAITRite / wearables (large samples)</li> <li>Mean preferred velocity:<ul> <li>Robust$\approx130\,\text{cm}\,\text{s}^{-1}$</li> <li>Almost-frail$\approx113\,\text{cm}\,\text{s}^{-1}$</li> <li>Frail$\approx90\,\text{cm}\,\text{s}^{-1}$</li></ul></li> <li>Consistent significant trends (except step-width CoV)<ul> <li>$\downarrow Stride length & walk ratio
• \uparrow Single & double-support times
• \uparrow$Absolute step width (but variability not always$\uparrow)

Where Does Gait Become Dysfunctional?

• Debate: “normal” aging vs. pathology; variability & dual-task cost key discriminators
• Older fallers show greater variability than age-matched non-fallers despite similar mean speed & strength

Kinematic & Kinetic Age-Related Changes

• Temporal-Spatial
  • \downarrow velocity, step/stride length & rate
  • \uparrow stride width, stance & double support; \downarrow$swing phase</li></ul></li> <li>Kinematics<ul> <li>Less vertical COM excursion</li> <li>Decreased arm swing; reduced hip/knee/ankle flexion; flatter foot strike</li> <li>More forward trunk flexion</li></ul></li> <li>Muscle Activation<ul> <li>$\uparrow$EMG of LE muscles (e.g., peroneus longus, gastroc)</li> <li>$\uparrow$agonist–antagonist co-contraction → joint stiffening, DOF reduction</li></ul></li> <li>Joint Kinetics<ul> <li>$\downarrow$plantar-flexor power at push-off</li> <li>$\downarrow$quadriceps absorption late stance</li> <li>Heavier reliance on hip extensors</li></ul></li> </ul> <h4 id="sixthvitalsigngaitspeed">“Sixth Vital Sign” – Gait Speed</h4> <ul> <li>Predicts: functional dependence, hospitalization, rehab needs, discharge destination, ambulation category</li> <li>Thresholds: inability to exceed$1.4\,\text{m}\,\text{s}^{-1} linked to poorer outcomes

  Assistive Devices

  • Cane: mild balance impairment, unilateral deficits, decreased ankle-foot proprioception (hand proprioception augments feedback)
  • Walker / rollator: moderate balance impairment, generalized weakness/pain; provide maximal stability
  • Paradox: cane/quad-cane users fall > walker users & > device-free peers (“moderately disabled” subgroup)

  Sarcopenia

  • High prevalence in females >60\text{ y}; progressive type II fiber atrophy
  • CT/MRI: increased intramuscular adipose; lost cross-section vs. active counterparts (e.g., 74-y triathlete vs. 74-y sedentary)
  • Assessment: 6-MWT, DXA, CT, MRI

  Exercise & Osteoporosis Considerations (Highlights)

  • “Sit less, move more” – embed PA in enjoyable daily routine
  • Moderate-impact WB + resistance → bone mass stimulus
  • Monitor intensity: Borg RPE or talk test (esp. on β-blockers where HR blunted)

  Clinical Framework (ICF Perspective)

  • Locomotor requirements: basic pattern generation + orientation/stability + adaptability
  • Systems approach: sensory degradation (vision, vestibular, proprioception) & cognitive load → conservative gait similar to early walkers

  Example Illustrations

  • Stick-figure modeling of trip recovery: maximal strength vs. moderate weakness vs. severe weakness (foot contacts & fall)
  • Graphs: four elder classes (Robust+, Robust, Frail, Frail−) show progressive \uparrow$step width$+$$\downarrow step/stride length

  Key Take-Home Messages & Counseling Points

  • Frailty is measurable, often reversible; screen using 5 criteria & gait speed
  • Falls result from intertwined intrinsic & extrinsic factors; ask about prior falls & FOF at every visit
  • Gait speed
  • Promote strength, power & dual-task training; address visual, vestibular & proprioceptive inputs
  • Encourage community engagement & meaningful activity (salutogenic model) for successful aging