NRS Week 7 Notes - Impaired Mobility + Case Study

Context and Course Positioning

Lecture by Brenton on impaired gait; content drawn from Shumway-Cook & Willacott textbook, chapter 15 in latest edition
Review of prior mobility content: gait cycle basics, spatial-temporal characteristics (step time, step length), joint forces/angles/moment arms, kinematics/kinetics
Neural control of gait; development (early milestones in walking); gait in older adults
This module: impairments in gait and their management; introduces research and innovations at the City West health clinic
Objectives (ICF framework focus): describe abnormal mobility with body structure/function impairments, activity limitations, participation restrictions; classify impairments by pathology (motor, sensory, cognitive); discuss management strategies; provide examples, videos, and practical/clinical implications; link to assessment (videos, documentation) and potential exam content
Practical emphasis: ability to document gait observations, plan management, and
recognise research innovations

ICF Framework and Impairment-Focused Description

Impaired gait
$\rightarrow$ abnormal movement
$\rightarrow$ impact on activity (e.g., walking, mobilising) and participation (social and practical mobility)
Body structure and function: impairments (e.g., reduced range of motion, reduced strength, tone/spasticity problems)
Impairments contribute to activity limitations and participation restrictions within real-world contexts (work, groups, transport, etc.)
Pathology-based gait classifications (to be used with caveat): ataxic gait (incoordination of foot placement), hemiparetic gait (one side affected, common after stroke)
Magnitude of pathology determines impairment severity and activity limitation; compensation strategies may modify gait (devices, learned patterns)
Key clinical point: assessment and intervention can target impairments, activities, and participation under the ICF framework

Classification of Gait Impairments (Motor, Sensory, Cognitive)

Motor impairments: impact on muscle force, tone, coordination, and postural control
Sensory impairments: somatosensory, visual, vestibular, perceptual problems; cognitive contributions (pain, fear, anxiety)
The next sections focus on motor impairments (weakness, spasticity, abnormal synergies, coordination), sensory impairments (peripheral neuropathy), and other factors (pain, fear, anxiety)

Motor Impairments in Gait

Weakness

Reduced ability to generate force; neural vs non-neural origins
- Neural: brain/spinal cord issues limiting supraspinal motor recruitment
- Non-neural: muscle-level execution limits despite neural drive

Example: Weak Dorsiflexors During Swing

Consequences: limited dorsiflexion in swing
$\rightarrow$ toe drag; difficulty achieving initial contact heel strike
Compensations: circumduction, vaulting
If dorsiflexors are weak, heel strike may be absent or minimal at initial contact
Illustration: video examples show right leg toe drag during swing and lack of dorsiflexion; compensatory hip/trunk strategies may occur

Ankle-Foot Orthosis (AFO) as a Common Intervention

AFO = ankle-foot orthoses; visible as a rigid plastic device behind the leg
Function: holds ankle at approximately $90^{\circ}$ (plantigrade) to prevent foot drop during swing
Effect: enables heel strike at initial contact and safer foot clearance
Limitation: restricts plantarflexion; may reduce push-off and forward progression
Clinical note: AFO improves swing clearance but does not fully restore push-off dynamics

Additional Video/Concepts: AFO Demonstration

The video sequence shows a patient with foot drop without brace, then with AFO; heel strike achieved with AFO but some gait cycle aspects remain affected

Hip Abductor Weakness

Hip abductors stabilise the pelvis during swing on the contralateral limb
Weakness
$\rightarrow$ contralateral pelvis drops (sag/Trendelenburg) or trunk lean (gluteus medius gait)
Long-term consequences: increased lumbar strain, higher energy expenditure
Typical presentation: pelvis drop during single-leg stance; visual comparison shows normal vs. weak abductor scenarios

Spasticity

A neurological condition; inappropriate muscle activation, especially when muscles are rapidly lengthened
Common in brain injury, stroke, CP; can limit dorsiflexion during swing and increase plantar flexor tone
Functional consequences: toe clearance loss, toe gripping, plantarflexion during swing, possible flat foot at contact
Associated phenomena: ground reaction force may become anterior to the knee, contributing to knee hyperextension moments
Video cues: left foot spastic plantar flexors produce reduced dorsiflexion and altered knee mechanics; spasticity can compromise heel strike and push-off
General effect: reduced push-off and overall gait efficiency

Other Motor Considerations

Abnormal muscle synergies (patterns firing in incorrect order)
Coordination issues (placement of feet and sequencing)
Musculoskeletal impairments affecting gait
Postural control deficits impacting stability during gait

Sensory Impairments and Their Impact on Gait

Role of Sensory Input in Gait

Sensory information helps maintain and adapt gait (base, foot placement, adaptation to terrain, initiation of swing, risk detection)

Peripheral Neuropathy (Key Example)

Loss of sensation at the feet
$\rightarrow$ ataxic gait with widened base of support
Compensations: stamping the feet for auditory feedback, reliance on vision (looking down), cautious gait in poor lighting
Increased attentional demand when walking (dual-task scenarios) and on uneven surfaces

Other Sensory Contributors

Visual problems (need to look down; risk with poor lighting)
Vestibular issues (postural control challenges)

Attentional and Cognitive Factors

Increased cognitive load can degrade gait when a secondary task is added (e.g., counting backwards, dual tasks)

Endangered Gait Patterns and Adaptive Responses

Recent injuries (ankle, knee) can produce painful gait with shorter stance phase on the affected limb
Protective stiffness or reduced loading to the painful limb
Use of walking aids (sticks, crutches) to offload the painful limb
Anxiety or fear can alter arm swing and base of support (e.g., cautious, lower centre of gravity)

Movement Strategies in Clinical Practice (Gait Retraining)

Three-Tier Approach Aligned to ICF

Impairment level: address underlying weaknesses or tone issues
Functional level: practice the task (walking) in a meaningful way
Strategy level: apply cues, attention manipulation, and task variation to improve performance

Impairment-Level Strategies

Strengthening weak muscles (e.g., dorsiflexors)
Tone management: stretching (passive/active), serial casting, and Botox as needed

Functional-Level Strategies

Whole practice: practice walking as a whole task in safe environments
Part practice: practice specific components (e.g., swing phase timing, weight shifting, step placement)
Varied environments: gym with parallel bars, outdoor environments to reflect real life

Strategy-Level Strategies

Verbal cueing: e.g., “step longer,” “take a bigger step,” etc.
Non-verbal and multimodal cues: visual, task-based cues
Attentional demand adjustments: reduce cognitive load where possible; gradually introduce dual-tasking
Dual-task training: combining walking with cognitive tasks (e.g., card-sorting while walking) to simulate real-life challenges

Individualised Application

Real-world tailoring: consider patient goals, e.g., community ambulation, faster walking, or safe street crossing
Practicable approach often involves a blend of impairment-, functional-, and strategy-level work

Example Cueing and Dual-Task Videos Described in Lecture

Parkinsonian gait example: using sticks to cue arm movement during swing
Card-sorting task on a treadmill: dual-task walking with cognitive load

Gait Retraining Equipment and Innovation (Clinical Research at UniSA and City West)

Rationale for Innovative Equipment

Address severe impairments where impairment/functional strategies may be insufficient

Core Equipment and Setup

Body weight support harness system: supports up to $90 ext{ kg}$ of body weight; user weight can be higher (e.g., $120 ext{ kg}$ ) but reduces supported body weight accordingly (e.g., up to 30 kg of user weight when at max) to enable upright training
Augmented reality screen: visual feedback to simulate real-world walking in engaging environments (e.g., forest scenes)
Projection/map treadmill integration: pressure-sensitive gait mat and visual cues/foot placement guidance
Mechanical assistance strings: provide limb assistance to facilitate movement when patient cannot move unaided

Goals and Measures

Assess changes in mobility and walking quality before and after therapy
Use interviews to capture patient perspectives on engagement and perceived impact

Case Example: Severe Spinal Cord Injury

Severe spinal cord injury (ASIA B, T1 level, chronic with sensory below injury but no motor movement)
Design: 10-session crossover study (control then intervention) to evaluate feasibility and impact
Outcome: upright positioning and ability to bear weight on the limbs allowed practice; after eight sessions, voluntary toe movement emerged (toe flexion) indicating motor activation where none existed previously; emotional significance for the patient

Interpretation of Case Example

Even in severe cases, engaging training with assistive tech can unlock residual capacity and drive neuroplastic changes

Environment Manipulation and Task Variation in Rehab

Gait over obstacles in a safe treadmill-based setup with virtual obstacles (log crossing) and reward-based feedback (score) to motivate task completion
Observed improvements: improved ability to adapt gait to environmental demands; increased confidence and community mobility (Functional Ambulation Category score improved in some patients)

Movement Strategy Innovation for Ataxic Gait

Use of projection-based footprints to guide step length and width; supports consistency and reduces gait variability
Incorporation of dual-tasking with visual feedback to enhance automaticity while maintaining accuracy

Brain Plasticity Window and Vagal Nerve Stimulation (VNS)

Found that motor recovery after stroke shows an initial rapid improvement followed by plateau; suggests a transient window of enhanced neuroplasticity (weeks 2–4) that can be broader
Research horizon: reopen or extend the window of plasticity to boost rehabilitation efficacy
Vagal nerve stimulation (via a small ear-based device) activates brain neurochemistry that may promote neuroplasticity
Trial design: randomised trial with real vs placebo VNS, combined with standard rehabilitation
Practical implication: if effective, VNS could be readily translated into clinical practice

Practical and Philosophical Takeaways from Research

Rehab is a substantial effort requiring weeks to months; patient engagement and motivational framing are critical
Creative, engaging approaches (gamified feedback, AR/VR, task variation) can improve adherence and outcomes
Emphasis on translating research innovations into real-world clinical practice

Clinical and Exam-Oriented Takeaways

Framework for describing impaired mobility: ICF model (impairments, activity limitations, participation restrictions)
Distinguishing impairment types helps with assessment planning and documentation for exams
Gait assessment in practice: assess from head-to-toe (or toe-to-head) to ensure no impairment is missed and to capture compensations
Common impairments and their gait signatures to
recognise in videos or in clinics: dorsiflexion weakness, hip abductor weakness, plantar flexor spasticity, sensory loss with widened base, ataxia, and fear/anxiety factors
Management strategies span impairment-focused (strength/tonus), functional practice (task-specific gait training), and strategy-focused approaches (cueing, dual tasks, environmental manipulation)
Be prepared to discuss both conventional approaches and innovative research findings (AR/VR, body weight support, obstacle training, dual-task paradigms, and VNS)

Practical Implications and Ethical/Philosophical Notes

Rehab requires collaboration, patient motivation, and adaptable strategies; a one-size-fits-all approach is ineffective
Innovative interventions should be evaluated for safety, feasibility, and patient-centered outcomes
Clear communication of goals and realistic expectations is essential for patient engagement and adherence

Exam Preparation Pointers

Be comfortable mapping impairments to the ICF framework and articulating how they affect activity and participation

- Be able to describe motor vs sensory impairment mechanisms and provide concrete gait examples (toe drag, heel strike, vaulting, circumduction, Trendelenburg, etc.)

Recognise and discuss common compensations and their limitations

Understand how different management levels interact (impairment-focused vs functional practice vs strategy cueing)
Be familiar with research-driven rehabilitation innovations and their clinical relevance (e.g., VNS, AR gait training, weight-supported treadmill training, dual-task gait training)

Quick Glossary and Notes

AFO: ankle-foot orthosis; maintains ankle at $90^{\circ}$ (plantigrade) to prevent foot drop but may limit push-off
Plantar flexors vs dorsiflexors: balance of push-off vs foot clearance during swing
Trendelenburg gait: pelvis drop on the swing side due to hip abductor weakness
Hemiparetic gait: gait pattern with unilateral impairment (common after stroke)
Ataxic gait: gait with poor coordination and wide base; high variability in step length/width
Functional Ambulation Category (FAC): a clinical score reflecting community mobility and independence
Asia Impairment Scale (ASIA): used to classify spinal cord injuries (e.g., Asia B = sensory preserved below injury, no motor function below injury)

References for Further Exploration

Ongoing University of South Australia (UniSA) gait rehabilitation research
City West health clinic engagement in innovative gait retraining technologies
Public-facing resources and summaries of neuroplasticity window and vagal nerve stimulation from the APA (as mentioned in lecture)

Contact and Further Discussion

Open invitation to email or visit for questions, discussion, and practical insights related to gait impairments, assessment, and rehabilitation planning

LECTURE 2

Case 1: Stroke (Bruce) – Clinical Gait Analysis and Interpretation

Context and Background

Case: Bruce, 45 years old, left MCA haemorrhagic stroke, occurred 4 weeks prior.
Haemorrhagic stroke notes
Historically more severe; approximately around half of patients may not survive this type in some contexts, making survival itself a positive outcome, though recovery trajectories tend to be prolonged compared to ischaemic strokes.
Hospital course and current status
Acute care at Royal Adelaide: 8 days.
Rehabilitation: Hampstead Rehab for 3 weeks post-acute care.
Recently discharged and home-safe status inferred.
Currently attending weekly physiotherapy at City West student clinic.
Deficits identified
Right hemiplegia (right-side weakness) and aphasia (language production impairment), indicating dominant-hemisphere involvement affecting speech and upper limb control.

Goals and SMART Framework

Initial goal: Bruce stated he wanted to walk better. This is too vague for SMART goals.
SMART questions to refine goals:
Specific: What exact walking ability is targeted?
Measurable: How will progress be measured?
Attainable/Realistic: Is the goal achievable within the planned rehab period?
Timely: What is the timeframe?
Patient-driven goal refinement
He expressed desire to walk faster (more functional in real-world tasks like crossing roads).
Context for community ambulation speed
Typical safe crossing speed benchmark: around ~0.80m/s for community ambulation.
Bruce’s discharge gait speed: ~0.60m/s, which is below the community requirement and supports the need for targeted speed improvement.

Observations from Gait Analysis

Assistive device and orthosis
Uses a quad-stick (four-point cane) for stability.
Wears an ankle-foot orthosis (AFO).
Strength and timing
Right lower limb weakness: manual muscle testing (MMT) around 2/5 on the right side.
Antigravity movement limited on the right; weaker initiation/start phase on the right limb.
Gait mechanics and deviations observed
Decreased stance phase on the right lower limb (shorter time spent on the paretic leg).
Left hip drop during loading response on the right limb, indicating pelvic/trunk control issues and asymmetric trunk/pelvic stability.
Right knee hyperextension in mid-stance (knee extending excessively, often to stabilise the limb).
Impaired swing limb advancement of the right leg (circumduction of the right hip to clear the foot during swing).
Forefoot contact at initial contact on the right foot (lack of heel strike) and knee flexion at initial contact (reduced knee extension at heel strike).
Effects of the AFO
AFO likely indicates dorsiflexor weakness/foot drop and contributes to forefoot contact and limited push-off.
AFO can limit plantarflexion during terminal stance, reducing propulsion and step length; potential consideration for later wean-off if strength improves.
Postural control considerations
Overall reduced postural control and balance in standing, requiring greater base of support (quad-stick) and possibly anticipatory balance strategies.
Implications for treatment focus
Target weaknesses: hip extensors, hip abductors, knee extensors (inner range), ankle dorsiflexors, and plantarflexors for push-off.
Improve stance phase duration on right limb and reduce compensatory patterns (circumduction, hip drop).
Improve heel strike and initial foot clearance to enable a more normalised gait pattern.

Potential Aetiologies and Cause-and-Effect Considerations

Impaired stance phase could be due to right lower limb weakness and poor postural control.
Left hip drop likely caused by weakness of the right hip adductors/abductors affecting pelvis stability.
Right knee hyperextension (mid-stance) may reflect weakness around knee extensors and adductors, closed-pack knee positioning, and compensatory extensor moments.
Forefoot contact could reflect dorsiflexor weakness, spasticity/rigidity, or ankle control limitations due to AFO and tone.
Impaired swing and hip circumduction point to hip flexor weakness and inadequate hip/knee control for proper foot clearance.

Clinician Reasoning and Assessment Strategy

Observations should drive objective testing:
Postural control assessment in standing (balance tests, anticipatory postural adjustments).
Strength testing of hip extensors/adductors, knee extensors, ankle dorsiflexors, plantarflexors; MM testing or a standardised scale.
Range of motion and joint moment assessment to identify limitations contributing to gait deviations.
Gait speed measurement with a timed walk test (e.g., 10-metre or 6-metre walk test) for objective progress tracking.
Correlate impairments with functional goals (e.g., increasing gait speed toward ~0.80m/s threshold) to inform treatment planning.

Management Plan (Case-Specific Implications)

Strengthening focus
Right hip extensors and abductors (e.g., hip abductor strengthening to reduce contralateral pelvic drop).
Quadriceps and hamstrings, with emphasis on learning inner range control around the knee to reduce knee hyperextension.
Ankle dorsiflexors to improve heel strike and foot clearance; plantarflexors to enhance push-off if timing permits.
Postural and sensory integration
Balance training and anticipatory postural control, particularly during the stance phase and during weight shift.
Gait retraining and device considerations
Reassess ongoing need for AFO as strength and control improve; potential weaning plan if dorsiflexion improves and heel strike returns.
Consider gait-specific training with objective progress measures (e.g., timed 10m walk).
Functional outcome target
Improve gait speed toward or beyond 0.80m/s in community contexts.
Education and safety
Set realistic expectations with patient about recovery trajectory (hemiplegia + aphasia impact).
Consider environmental adaptations (home setup, safety during ambulation).

Case 2: ACL Injury – Neuromuscular Control and Gait Adaptation (Neuroplasticity in Rehab)

Context and Rationale for Gait Analysis in ACL Rehab

ACL injury leads to compensatory neuromuscular changes and altered gait mechanics.
Neurophysiological changes observed after ACL injury
Decreased activation in the motor cortex representation for the knee in the contralateral hemisphere to the injury site.
Increased intracortical inhibition and changes in cerebellar representations; overall dynamic brain adaptations occur quickly (days to weeks).
Functional implications
Increased reliance on visual strategies (looking at the ground) due to altered knee representation and proprioceptive feedback.
Elevated cognitive demands during walking as the system recalibrates; movement becomes less automatic and more conscious.
Practical consequence
Rehabilitation must address both knee mechanics and cortical-motor control to restore efficient gait and function.
Relevance to sports and performance
Sports often impose high demands: rapid changes in direction, jumping, landing, kicks, and physical contact; rehab must prepare for these dynamic tasks.
Psychological and identity aspects
Athletes may experience identity disruption and pressure to return to sport; rehab should integrate psychological support and goal alignment.

Neurophysiology of Gait and Rehabilitation Implications

Visual reliance and cognitive load implications
Increased reliance on visual feedback and attention during early rehabilitation stages.
Training should progressively reduce external cues to promote automaticity and proprioceptive integration.
Neuromotor retraining strategies
Emphasise external focus of attention to improve automatic motor control and reduce conscious motor strategies.
Promote implicit learning to foster automatic movement patterns with less cognitive load.

Motor Learning Principles and Rehabilitation Strategies Relevant to ACL Rehab

External focus of attention
Direct attention to environmental outcomes rather than body mechanics (e.g., aim to move a cone or reach a target rather than focusing on knee angle).
Benefits: accelerates early learning, increases intracortical inhibition, and supports task performance under dynamic conditions.
Implicit learning and generative instructions
Use analogies/metaphors to guide movement without explicit focus on joint angles (e.g., imagine the leg as a spring; push off to spring upward).
Benefits include improved automaticity and reduced cognitive load during performance.
Salience and task relevance
Ensure training tasks are meaningful to sport context (e.g., jump height relevant to blocking, landing mechanics in a basketball rebound).
Enhances sensory-motor and premotor activation through task relevance.
Variable and contextual interference exercises
Variable practice, random practice schedules to strengthen adaptable motor programs.
Dual-task training to simulate real-world demands (e.g., cognitive tasks while performing proprioceptive tasks).
Perturbation and progression of complexity
Introduce controlled perturbations to challenge postural control and knee stability under stress.
Use virtual reality or computer-aided tasks to diversify sensory inputs and decision-making demands.
Proprioception and joint control
Emphasise knee proprioception, balance, and multi-joint control with tasks simulating sport-specific demands (stops, pivots, decelerations).
Specific sport considerations
Netball: start-stop, catching, and momentum control; AFL/basketball: change of direction, jumping/landing with knee protection.
Psychological considerations
Identity and return-to-sport expectations; address anxiety, motivation, and confidence through graded exposure and success experiences.

Practical Rehab Planning for ACL Rehab

Environment and task focus
Rehab setting tends toward closed, controlled tasks initially; progress towards open, dynamic environments resembling sport.
Task specificity and outcome orientation
Shift emphasis from single-joint metrics to whole-task outcomes (e.g., ability to land safely, change direction, or sprint with control).
Feedback strategies
High-frequency, multisensory feedback (visual, tactile, verbal) early on; taper as automaticity improves.
Salience-driven progressions
Start with highly relevant tasks (sport-specific actions) and gradually generalise to broader activities.

Connections to Foundational Principles and Real-World Relevance

Case 1 contrasts stroke-induced motor impairments with postural control demands and gait-specific adaptations; emphasises long recovery trajectory and the role of assistive devices.
Case 2 highlights brain-muscle coupling changes after ACL injury and demonstrates how rehabilitation must address both neural plasticity and mechanical knee function.
Across both cases, the integration of observation, objective measurement, and hypothesis-driven treatment aligns with clinical reasoning and evidence-based practice.

Practical Implications and Ethical/Philosophical Considerations

Patient-centred goals and SMART framework encourage autonomy and realistic expectations.
Psychological burden of injury, identity disruption, and sport-related pressures require holistic care beyond physical rehabilitation.
Use of assistive devices (AFO, quad-stick) should be continually reassessed for potential wean-off as function improves, balancing safety with independence.
The clinician must balance aggressive restoration of function with safety in the context of potential pain, fatigue, and risk of re-injury.

Key Numerical References and Formulas (LaTeX)

Community ambulation speed threshold: ~0.80m/s
Bruce’s discharge gait speed: ~0.60m/s
Right lower limb strength: MMT = 2/5
Note on haemorrhagic stroke prognosis: survival ~0.5 (approximate, context-dependent)

Critical Questions and Discussion Prompts

Define hemiplegia and aphasia in the context of stroke.
Why is a SMART goal important in a gait rehabilitation plan?
How would you decide when to wean the AFO in case 1? What metrics would you monitor?
In case 2, how might external focus and implicit learning be implemented in a sport like basketball or netball?
How can we integrate motor learning principles with neuromuscular training to optimise return-to-sport timelines while minimising re-injury risk?

Summary Takeaways

Gait analysis in clinical practice requires observation, objective measurement, and a testable hypothesis about impairments driving gait deviations.
Stroke gait is characterised by hemiparesis, spasticity, and compensations; goals should be SMART and targeted to functional speed and stability.
ACL injuries involve rapid brain-muscle adaptations; rehabilitation should address both knee mechanics and cortical-motor control through evidence-based motor learning strategies.
Leveraging external focus, implicit learning, salience, and progressive perturbations can accelerate motor learning and functional recovery while reflecting real-world sport demands.

References to Potential Audience Interaction (In-Class Prompts)

What is hemiplegia? What is aphasia? (definitions and examples)
What would be the SMART refinement of Bruce’s goal to walk faster within a 4-6 week window? What tests would you use to measure progress?
How might you determine if Bruce can safely discontinue the AFO in the near term?
For the ACL case, what specific sport-related