Unit 6C - Lower-Extremity Motor Control Deficits

Overview

  • Unit VI-C focuses on lower-extremity (LE) motor–control deficits after neurologic injury (e.g., CVA, TBI, incomplete SCI).
  • Three recurring clinical goals:
    • ↑\uparrow Tone in flaccid musculature (first for mobility, later for weight-bearing stability).
    • ↓\downarrow Tone in spastic musculature.
    • ↑\uparrow Active isolated movement and selective motor control (breaking out of mass-synergy patterns).
  • Treatment concepts threaded through the unit:
    • Motor-learning progression: PROM → AAROM → AROM → resisted / functional.
    • Use of sensory stimuli (stretch, tapping, vibration, cutaneous input, approximation, traction, visual tracking, verbal cueing).
    • Avoiding reinforcement of abnormal reflex-synergy patterns (Brunnstrom flexion / extension synergies).
    • Application of developmental-sequence positions (supine → hook-lying / bridging → quadruped → tall-kneel → half-kneel → modified plantigrade → standing / pre-gait).
    • Safety: guard weak limb, maintain neutral ankle to prevent PF/inversion contractures, respect fatigue.

Flaccid LE – Increasing Tone for Mobility

  • Global goal: "wake-up" a hypotonic leg so the patient can begin moving it voluntarily.
  • Key principle: provide strong facilitatory input concurrently with—or immediately followed by—voluntary effort; always assist as much as needed to complete the task with correct kinematics.

Gravity-Eliminated (GE) Facilitation Techniques

  • Quick stretch ➔ active movement.
    • Start in GE plane (powder board, friction-less surface).
    • Give brisk elongation to target muscle; cue patient to finish the movement.
  • Cutaneous input with active movement:
    • Brushing or tapping the muscle belly.
    • Hand-held vibrator on muscle belly (100–200 Hz for < 30 s to avoid fatigue).
    • NMES: place electrodes over motor points, synchronize "on" phase with patient attempt.
  • Therapist body-mechanics tip: powder board reduces friction and therapist load.

Overflow / Associated Reactions

  • Ramiste’s phenomenon (proprioceptive reflex overflow): resisted hip abduction/adduction on the strong side elicits same motion on the paretic side.
    • Application: place both hips either flexed or extended; give stronger resistance to non-paretic limb, minimal resistance or assistance to paretic limb.

Rhythmic Combination Progressions

  • Progress to single-leg hip abduction in hook-lying: quick stretch hip abductors → active hold, then return.
  • PNF LE diagonals (D1flex/D1ext, D2flex/D2ext):
    • Start active-assist, progress to resisted.
    • Example of reciprocal inhibition overflow: resist plantar flexion (PF) on strong leg → facilitatory overflow for gross hip/knee flexion on weak leg; resist dorsiflexion (DF) on strong leg → overflow for hip/knee extension on weak leg.

Trunk-Pelvic Rotational Activities

  • Lower-trunk rotation (LTR) / "knee rocks": supine, knees together; therapist guides LE side-to-side while cueing head rotation opposite knees (advanced version adds eye/head dissociation for vestibular input).
  • Side-lying rotational activities: patient in side-lying, therapist facilitates pelvic/trunk dissociation while maintaining LE adduction or other desired alignment.

Early Bridging Series (Mobility Emphasis)

  • Assisted hip/knee flexion: PTA supports plantar surface to avoid PF reflex, then guides femur during lifting phase.
  • Bridging hierarchy:
    1. Bridging with therapist assist (tactile cues or draw-sheet under hips).
    2. Bridging with stool (feet on raised surface reduces hip flexor demand).
    3. Four-step bridges (mobility + stability):
      • Step 1 – raise pelvis.
      • Step 2 – task variant (raise strong leg OR abduct both legs).
      • Step 3 – reverse Step 2.
      • Step 4 – lower pelvis.

Flaccid LE – Increasing Tone for Stability in Weight-Bearing

  • Shift emphasis from mobility to proximal and distal stability so the limb can accept body weight.

Supine Stability Bridges

  • Bilateral bridge with approximation: therapist applies axial compression through knees to facilitate co-contraction.
  • Single-leg bridge on affected leg (strong leg extended and relaxed).
  • SLR on strong leg while sustaining bridge on affected leg (adds dynamic challenge).
  • Progression variables: hold time, reps, surface compliance.

Developmental-Sequence Stability Tasks

  1. Quadruped: weight shifts—antero-posterior (AP), then diagonal. Add rhythmic stabilization (RS) at shoulder girdle or pelvis; apply approximation through knees/hips.
  2. Tall-kneel / kneel-standing: same strategies; add upper-extremity (UE) PNF chop–lift to drive trunk/hip activation.
  3. Half-kneel / partial-kneel variants:
    • Entry either from standing (step-back into lunge) or from tall-kneel (bring one leg forward).
    • Modified half-kneel in parallel bars or against high-low mat for additional UE support; therapist may assist hip extension of forward (weak) limb.

Standing Pre-Gait in Parallel Bars

  • Side-to-side weight shifts: start in modified plantigrade or on elevated surface if needed.
  • Therapist may give maximal assist and block knee.
  • Progress to single-limb stance: lift strong leg, count hold time; step forward/back with strong leg while weak leg remains WB.

Spastic LE – Decreasing Tone

  • Pathophysiology: hyper-excitability of stretch reflex ➔ excessive co-contraction, loss of selective control.

Inhibitory Techniques

  • Prolonged stretch / positioning in opposite direction of spastic pull (e.g., sustained ankle DF with knee extension).
  • Cryotherapy (cold) over agonist for 20 min → temporary ↓\downarrow spindle firing.
  • Activation of antagonist (reciprocal inhibition): e.g., facilitate dorsiflexors to inhibit plantar-flexor spasticity.
  • Slow rotational movements of trunk or extremity—activates vestibular / GTO inhibitory pathways.

Reflex-Inhibiting Postures (RIP)

  • Foot: neutral DF + eversion; toes abducted with gentle traction (inhibits toe clawing, PF & inversion).
  • Must maintain positioning during exercise; always return passively to starting posture.
  • Can combine with:
    • PNF pelvic patterns (anterior–posterior elevation/depression) performed passively → AAROM.
    • Air-splints for prolonged stretch of knee or ankle (inflate for 15–20 min sessions).

Functional Movement Difficulty – Increasing Active Isolated Motion

  • Objective: break out of Brunnstrom mass synergies; achieve selective control in single joints/planes.

Brunnstrom Synergy Review

  • LE flexion synergy: hip flex+ABD+ER\text{flex} + \text{ABD} + \text{ER}, knee flex\text{flex} (~90∘90^{\circ}), ankle DF + inversion, toe extension.
  • LE extension synergy: hip ext+ADD+IR\text{ext} + \text{ADD} + \text{IR}, knee ext\text{ext}, ankle PF + inversion, toe flexion.
  • Treatment principle: use RIP and precise manual contacts to prevent unwanted components.

Progression of Selective-Control Tasks

  1. Gross hip/knee flexion & extension (supine): therapist holds foot in DF+eversion. Provide lateral tactile cue (TC) at distal femur during flexion; medial TC during extension to prevent synergy drift.
  2. Frenkel’s exercises (coordination drills): patient slides heel along specific pathways on table; tactile cue to distal femur counters synergy.
  3. Bridging variations (now for selective hip extensors): two-leg → involved-leg-only → four-step variants → add ABD/ADD, pelvic rotation, or manual resistance.
  4. Isolated hip flexion out of synergy:
    • Supine: PTA grips lateral border of foot (DF+eversion) + lateral distal femur to block ABD/ER.
    • Side-lying on powder board or sitting; same RIP contacts.
    • Standing: march onto stool or numbered floor targets; therapist guards for ankle inversion and hip ABD/ER.
  5. Isolated hip ABD/ADD with hip flexed: patient actively performs both directions while therapist monitors alignment.
  6. Isolated knee extension:
    • Supine, half-sitting, or standing with affected thigh abducted; lateral foot RIP + medial distal-femur cue to prevent hip ADD.
    • Prone, side-lying, or against wall (advanced home exercise) for end-range quad control—avoid ankle inversion.
  7. Isolated ankle DF:
    • Patient in sitting; therapist holds foot only (eversion) while stabilizing distal femur laterally.
    • Combine with knee flex/extend for functional sequencing (e.g., DF as knee extends, PF as knee flexes).
  8. Isolated knee flexion without inversion:
    • Prone or side-lying (if poor control); prohibit hip ER, anterior pelvic tilt.
    • Sitting: therapist blocks ankle inversion and hip ER.

Integrated Task Examples

  • "Manually resisted bridges": therapist supplies graded resistance at pelvis, thighs, or knees to challenge selective recruitment while maintaining neutral alignment.
  • Pelvic rotation while bridging (left/right) to differentiate hip extensors from trunk rotators.

Advanced & Assistive Technologies

  • NMES or FES on dorsiflexors may become permanent orthotic substitute (e.g., Bioness wireless stim system) when selective DF remains absent.

Ethical / Practical Considerations

  • Protect joints lacking tone (flaccid) from hyper-extension or subluxation; avoid aggressive ROM on spastic joints without adequate sedation–stretch cycle.
  • Home-exercise compliance: provide clear tactile-placement diagrams so patient/caregiver can replicate RIP and manual contacts safely.
  • Re-evaluate tone (Modified Ashworth Scale), motor stages (Brunnstrom), and functional outcomes (Functional Gait Assessment) each session to titrate facilitation vs. inhibition.

Connections to Previous Content

  • Builds on Unit VI-A concepts of proximal trunk control and Unit VI-B upper-extremity facilitation/inhibition strategies.
  • Reiterates principles from neurophysiologic approaches (Rood – sensory stimulation, Brunnstrom – synergy stages, PNF – diagonal patterns & developmental sequence, Bobath/NDT – RIP & postural control).

Real-World Relevance

  • Techniques mirror bedside practice in acute neuro wards (e.g., early bridging for pressure-relief training).
  • Pre-gait standing tasks are stepping-stones to gait training with orthoses or FES devices.
  • Selective‐movement drills reduce fall-risk by minimizing involuntary synergy kicks during transfers or stair climbing.

Numerical / Quantitative References

  • "Count holds" during single-limb stance or bridging: aim for 10 s10\,\text{s} initially; progress by 5 s5\,\text{s} increments.
  • sustained stretch time: minimum 30 s30\,\text{s}, optimal >60\,\text{s} to influence viscoelastic tissue and reflex.
  • Cryotherapy dosage: 15–20 min15–20\,\text{min} per muscle group, skin temp drop >10^{\circ}\text{C} for effective spindle inhibition.
  • Vibration frequency: 100–200 Hz100–200\,\text{Hz}; amplitude <2\,\text{mm}.

Quick Glossary

  • GE = Gravity Eliminated.
  • PF = Plantar Flexion; DF = Dorsiflexion.
  • ABD = Abduction; ADD = Adduction.
  • RIP = Reflex Inhibiting Posture.
  • RS = Rhythmic Stabilization (PNF technique).
  • AA = Active-Assistive.
  • TC = Tactile Cue.
  • AP = Antero-Posterior.
  • NMES = Neuromuscular Electrical Stimulation.
  • FES = Functional Electrical Stimulation.
  • PTA = Physical Therapist Assistant.
  • "Quick stretch" = Rood-based rapid muscle elongation to facilitate spindle firing.

Study Tips

  • Pair each intervention with its underlying neurophysiologic rationale to aid memory (e.g., quick stretch → spindle activation → ↑\uparrow alpha-motor neuron firing).
  • Practice drawing the Brunnstrom synergy diagrams; label which components you must block when aiming for isolated motion.
  • Form checklists for each developmental position (quadruped, tall-kneel, half-kneel) specifying: starting alignment, therapist hands, facilitation/inhibition cues, progression criteria.
  • Use the numerical parameters provided to create sample treatment plans (e.g., "3 × 10 bridges, 5-s hold, 1-min rest").