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
    • \downarrow\text{VO}_2\text{ max}
    • \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}
  • Requires UE push to rise from chair
  • LE weakness (esp. proximal, knee)
  • Balance/gait impairments
  • Use of assistive device (cane users \approx 2\times risk)
  • Hx of falls or FOF
  • Slow TUG, weak knee, proprioceptive loss (diabetes, post-stroke), female sex, antidepressant use

Extrinsic / Environmental Risk Factors

  • Multiple meds (\ge4 or psychoactive)
  • Crowded, noisy, cluttered spaces; animals
  • Slippery surfaces, poor lighting, throw rugs, uneven sidewalks, stairs w/o rails

Greatest Relative Risks (top 6)

  1. Previous fall
  2. Balance impairment
  3. Muscle weakness
  4. Vision impairment
  5. >4 meds / psychoactives
  6. Reported gait impairment

Fall-Risk Clinical Algorithm (AGS 2017)

  1. Screen ALL adults \ge65 y (or younger but sedentary/frail-appearing)
  2. Ask: “Have you fallen in the past year?”
    • \ge2 falls or any fall with injury ⇒ high risk
  3. Ask re: acute/Recent fall? Difficulty with walking/balance?
  4. Positive response → full multifactorial assessment ± referral

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}

Gait Parameters Across Robust→Frail Continuum

  • Data via GAITRite / wearables (large samples)
  • Mean preferred velocity:
    • Robust \approx130\,\text{cm}\,\text{s}^{-1}
    • Almost-frail \approx113\,\text{cm}\,\text{s}^{-1}
    • Frail \approx90\,\text{cm}\,\text{s}^{-1}
  • Consistent significant trends (except step-width CoV)
    • \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
  • Kinematics
    • Less vertical COM excursion
    • Decreased arm swing; reduced hip/knee/ankle flexion; flatter foot strike
    • More forward trunk flexion
  • Muscle Activation
    • \uparrow EMG of LE muscles (e.g., peroneus longus, gastroc)
    • \uparrow agonist–antagonist co-contraction → joint stiffening, DOF reduction
  • Joint Kinetics
    • \downarrow plantar-flexor power at push-off
    • \downarrow quadriceps absorption late stance
    • Heavier reliance on hip extensors

“Sixth Vital Sign” – Gait Speed

  • Predicts: functional dependence, hospitalization, rehab needs, discharge destination, ambulation category
  • 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