NCT03969927 is an observational study evaluating the validity and reliability of a portable driving simulator for assessing driving ability in individuals with neurological conditions including Parkinson's disease, stroke, and multiple sclerosis. The study compares a low-fidelity portable driving simulator (PDS) against a high-fidelity fixed-base simulator to determine whether portable devices can provide adequate assessment capabilities for clinical and research purposes.
This research addresses a critical need in neurorehabilitation: the ability to objectively assess driving fitness in patients with neurological conditions who may be at increased risk for driving-related accidents. Traditional driving assessments require expensive simulator equipment or on-road testing, limiting accessibility. Portable simulators could enable more widespread screening and follow-up evaluation.
| Attribute |
Value |
| NCT Number |
NCT03969927 |
| Status |
Recruiting (as of August 2024) |
| Study Type |
Observational |
| Conditions |
Parkinson's Disease, Stroke, Multiple Sclerosis |
| Interventions |
Low-Fidelity Portable Driving Simulator vs. High-Fidelity Fixed-Base Simulator |
| Sponsor |
University of Kansas Medical Center |
| Principal Investigator |
Abiodun E. Akinwuntan, PhD |
| Start Date |
August 28, 2019 |
| Estimated Completion |
June 30, 2025 |
| Enrollment |
Not specified |
- Validate Portable Simulator: Determine whether a low-fidelity portable driving simulator can provide valid measurements of driving performance compared to high-fidelity systems
- Assess Usability: Evaluate user-friendliness of the portable device across different patient populations
- Measure Simulator Sickness: Assess the incidence and severity of simulator sickness symptoms with portable vs. fixed-base systems
- Compare Driving Metrics: Evaluate lane position maintenance, speed adherence, traffic light reaction times, and overall reaction time between simulator types
- Establish Reliability: Determine test-retest reliability of the portable simulator
- Population-Specific Analysis: Compare performance across Parkinson's disease, stroke, and multiple sclerosis groups
| Measure |
Description |
| User-Friendliness |
Likert scale (1-5) assessing ease of use and participant satisfaction |
| Simulator Sickness |
Simulator Sickness Questionnaire (SSQ) scoring range 0-228.14 |
| Driving Performance |
Composite score including lane position, speed adherence, traffic light reaction, and reaction time |
- Comparison of individual driving metrics between simulator types
- Correlation analysis between portable and high-fidelity measurements
- Subgroup analysis by neurological condition
The study employs a cross-sectional, within-subjects design where each participant completes driving tasks on both the portable and high-fidelity simulators. This approach allows direct comparison of the two assessment methods within the same individual, controlling for between-subject variability.
- Baseline Assessment: Demographics, medical history, driving history
- Cognitive Screening: Mini-Mental State Examination (MMSE) score ≥24 required for eligibility
- Vision Testing: Binocular acuity at least 20/60
- Driving Tasks: Standardized scenarios including lane keeping, speed regulation, traffic light response, and hazard detection
- Adults aged 25-75 years
- Diagnosis of Parkinson's disease, stroke, or multiple sclerosis
- Valid driver's license for at least 3 years
- MMSE score ≥24 (cognitive eligibility)
- Binocular visual acuity at least 20/60
- Severe motor impairment preventing simulator interaction
- Active medical conditions contraindicated for driving
- Prior participation in this study
- Inability to provide informed consent
Driving assessment is particularly relevant for Parkinson's disease patients due to several disease-specific factors:
- Bradykinesia and rigidity can affect reaction time and vehicle control
- Tremor may interfere with steering wheel manipulation
- Postural instability can compromise emergency maneuver execution
- Executive dysfunction affects decision-making and divided attention
- Visual processing deficits may impair hazard recognition
- Memory impairments can affect navigation and task sequencing
- Dopaminergic medications may cause daytime sleepiness
- On-off fluctuations can create unpredictable driving capability
- Dyskinesias may interfere with safe vehicle operation
A validated portable driving simulator could:
- Enable remote monitoring of driving fitness in PD patients
- Provide objective data for clinical driving recommendations
- Facilitate tracking of disease progression impact on driving
- Support rehabilitation interventions targeting driving-specific skills
The low-fidelity portable driving simulator under evaluation includes:
| Component |
Specification |
| Display |
Laptop or tablet screen (12-15 inch) |
| Controls |
Keyboard-based or basic joystick |
| Software |
Custom driving scenario software |
| Setup Time |
< 10 minutes |
| Portability |
Fits in standard carrying case |
| Cost |
< $5,000 |
The comparison system includes:
| Component |
Specification |
| Display |
Multi-screen immersive display (180°+ field of view) |
| Controls |
Force-feedback steering wheel, brake/acceleration pedals |
| Motion |
Platform with 3-6 degrees of freedom motion |
| Software |
Full physics engine with realistic vehicle dynamics |
| Setup Time |
30-60 minutes |
| Space |
Dedicated room required |
| Cost |
$100,000-500,000 |
The fundamental differences between portable and high-fidelity systems affect their utility:
- Visual Fidelity: Portable simulators use 2D displays while high-fidelity systems provide immersive 3D environments
- Control Fidelity: Basic input devices cannot replicate the tactile feedback of real vehicle controls
- Motion Cues: Portable systems lack motion feedback that contributes to driving immersion
- Scenarios: Portable systems offer fewer and simpler driving scenarios
However, for basic assessment metrics like lane position, reaction time, and speed maintenance, portable systems may provide adequate validity.
¶ Lane Position Maintenance
This metric evaluates the driver's ability to maintain proper lane positioning:
- Measure: Standard deviation of lateral lane position
- Units: Meters from lane center
- PD Relevance: Impaired by bradykinesia affecting steering corrections and visual-spatial deficits
Compliance with speed limits and appropriate speed selection:
- Measure: Deviation from posted speed limit, speed variability
- Units: km/h or mph
- PD Relevance: Affected by impaired judgment, bradykinesia in acceleration/deceleration
Response time and accuracy when approaching traffic signals:
- Measure: Reaction time from light change to brake application
- Units: Seconds
- PD Relevance: Delayed by bradykinesia, impaired visual processing, cognitive slowing
Recognition and response to unexpected road hazards:
- Measure: Time to detection, avoidance maneuvers
- Units: Seconds, response accuracy
- PD Relevance: Compromised by reduced divided attention, executive dysfunction
Composite measure of cognitive and motor response:
- Measure: Complex reaction time tasks
- Units: Milliseconds
- PD Relevance: Significantly prolonged in PD due to combined cognitive-motor impairment
- Compare PDS metrics against gold-standard high-fidelity simulator
- Establish correlation coefficients for each metric
- Determine measurement error and reliability
- Collect normative data from healthy controls across age groups
- Establish cut-off scores for driving fitness
- Account for learning effects with repeated testing
- Develop decision algorithm for driving recommendation
- Create screening protocols for clinicians
- Establish retesting intervals for disease progression monitoring
- Enable at-home monitoring with consumer-grade equipment
- Track longitudinal changes in driving fitness
- Alert clinicians to concerning trends
¶ Regulatory and Safety Considerations
In most jurisdictions, driving is regulated but not systematically monitored:
- Self-Reporting: Patients typically must report medical conditions
- Physician Reporting: Varies by jurisdiction (some have mandatory reporting)
- Practical Testing: Often only triggered by accidents or incidents
Portable simulators could provide objective monitoring between clinical visits.
Simulator sickness is a significant concern that can affect both assessment validity and participant safety:
Symptoms:
- Nausea and vomiting
- Dizziness and disorientation
- Headache
- Visual discomfort
PD-Specific Concerns:
- Patients with autonomic dysfunction may be more susceptible
- Baseline dizziness from PD medications may compound effects
- Need for pre-screening for history of motion sickness
Portable driving assessment technology is advancing rapidly:
- Virtual Reality Integration: VR headsets provide immersive experience with portable devices
- Smartphone Compatibility: Phone-based assessment becoming feasible
- AI-Powered Analysis: Machine learning for automated performance scoring
- Biometric Integration: Heart rate, eye tracking for comprehensive assessment
Validated portable simulators could enable:
- Multi-Site Trials: Standardized assessment across geographic locations
- Longitudinal Monitoring: Track driving changes over disease progression
- Intervention Studies: Measure effects of medications or rehabilitation
- Telehealth Integration: Remote assessment for patients with mobility limitations
Driving is a complex instrumental activity of daily living that significantly impacts independence, quality of life, and employment for individuals with Parkinson's disease. The progressive nature of PD eventually compromises the motor, cognitive, and visual abilities essential for safe vehicle operation. Approximately 25-50% of individuals with PD eventually cease driving, with driving cessation occurring on average 3-5 years after diagnosis, though significant variability exists based on disease severity, comorbidities, and individual circumstances.
The loss of driving privileges has profound consequences:
Functional Impact:
- Reduced independence in daily activities
- Increased reliance on family members or public transportation
- Limited access to healthcare appointments, social activities, and community engagement
- Potential loss of employment for younger patients
Psychological Impact:
- Depression and anxiety related to loss of independence
- Reduced self-esteem and sense of self-efficacy
- Social isolation and withdrawal
- Family strain due to increased caregiving demands
Economic Impact:
- Annual cost of PD-related driving cessation estimated at $10,000-20,000 per patient
- Increased healthcare costs due to transportation barriers
- Lost productivity for patients and caregivers
Multiple PD-related factors impair driving ability:
Motor Symptoms:
- Bradykinesia affects reaction time and physical responses
- Rigidity limits neck rotation and mirror checking
- Tremor interferes with steering wheel control
- Postural instability compromises emergency maneuvers
- Freezing of gait can occur while driving
Cognitive Symptoms:
- Executive dysfunction impairs decision-making and divided attention
- Visual-spatial deficits affect lane positioning and hazard detection
- Memory impairment may affect route navigation
- Attention deficits reduce ability to process multiple stimuli
- Psychomotor slowing extends reaction times
Visual Symptoms:
- Reduced contrast sensitivity affects low-light driving
- Color vision deficits may impair traffic signal recognition
- Diplopia (double vision) can occur with PD medications
- Visual field defects may reduce hazard awareness
Non-Motor Symptoms:
- Daytime sleepiness from PD or medications
- Orthostatic hypotension causes dizziness
- Anxiety and panic can impair driving
Medication Effects:
- Dopaminergic medications can cause sudden "off" periods
- Dyskinesias may interfere with vehicle control
- Sleep attacks (sudden onset of sleep) are rare but dangerous
Currently available driving assessment methods include:
On-Road Testing:
- Gold standard but resource-intensive
- Requires certified examiner and appropriate vehicle
- Not available in all regions
- May not be covered by insurance
- Can be stressful for patients
High-Fidelity Simulation:
- Excellent validity but cost-prohibitive
- Requires dedicated space and equipment
- Not portable or accessible
- Limited availability at specialized centers
Paper-Based Tests:
- Useful screening tools but do not assess actual driving
- Examples: Trail Making Test, Useful Field of View
- Do not capture the integration of skills needed for driving
Self and Caregiver Reports:
- Subjective and potentially unreliable
- May underreport or overreport difficulties
- Useful but not sufficient alone
Portable driving simulators offer a middle ground:
Advantages:
- More valid than paper tests (includes actual driving behavior)
- More accessible than high-fidelity simulators
- Lower cost allows wider deployment
- Can be used in community settings
- Enables longitudinal monitoring
- Can be deployed in patient's home
Challenges:
- Lower fidelity than fixed simulators
- May not replicate all driving scenarios
- Learning effects with repeated testing
- Technical reliability concerns
The trial employs a cross-sectional, within-subjects design:
Design Rationale:
- Each participant serves as their own control
- Eliminates between-subject variability
- Requires smaller sample size
- Allows direct comparison of simulator types
Procedure:
- Participants complete driving tasks on both simulators
- Order randomized to control for order effects
- Adequate washout between sessions
- Same scenarios presented on both systems
Assessment Environment:
- Standardized lighting conditions
- Consistent instructions
- Trained research staff present
- Same cognitive screening conducted
Lane Keeping:
- Standard highway driving scenario
- Maintain position in lane
- No other traffic
- 3-5 minute duration
Speed Regulation:
- Variable speed limit zones
- Maintain appropriate speed
- Smooth acceleration/deceleration
- 3-5 minute duration
Traffic Light Response:
- Intersections with signal changes
- Stop on red, proceed on green
- Yellow light decisions
- 5-10 scenarios
Hazard Detection:
- Pedestrians entering road
- Vehicles merging
- Road debris
- Unexpected obstacles
Complex Reaction Time:
- Multiple stimuli presented
- Varied response requirements
- Measures cognitive processing speed
Training:
- Research staff trained on both systems
- Standardized instructions
- Consistent prompts
Monitoring:
- Real-time observation during testing
- Technical issues recorded
- Data integrity checks
Participant Instructions:
- Clear explanation of tasks
- Practice trials before data collection
- Encouragement to do their best
The trial assesses multiple types of validity:
Concurrent Validity:
- Correlation between portable and high-fidelity metrics
- Expected: moderate to high correlation (r > 0.5)
- Different metrics may have different validity
Construct Validity:
- Do metrics measure the intended constructs?
- Comparison with established measures
- Known-groups validity (PD vs. controls)
Predictive Validity:
- Do simulator metrics predict on-road performance?
- More difficult to assess (requires on-road testing)
- May be assessed in future studies
Based on prior research, we expect:
High Correlation Metrics:
- Lane position standard deviation
- Speed maintenance
- Simple reaction time
Lower Correlation Metrics:
- Complex scenario responses
- Hazard detection
- Real-world judgment
Test-Retest Reliability:
- Important for longitudinal monitoring
- Expected: moderate to high reliability
- Learning effects may affect reliability
Internal Consistency:
- Do metrics correlate within domains?
- Different aspects of driving may cluster
If the portable simulator proves valid, implementation pathways include:
Phase 1: Clinical Validation
- Establish cut-off scores for safety concerns
- Validate against on-road performance
- Develop interpretation guidelines
Phase 2: Clinical Integration
- Integrate into movement disorder clinics
- Train clinicians on interpretation
- Develop decision algorithms
Phase 3: Patient Monitoring
- Enable at-home periodic assessment
- Track changes over disease progression
- Alert clinicians to concerning trends
Clinicians need clear guidance:
Algorithm Components:
- Baseline assessment at diagnosis
- Periodic screening (annually or biannually)
- Triggered assessment (after significant change)
- Clear referral criteria for on-road testing
Considerations:
- Must balance safety with autonomy
- Consider patient and family preferences
- Account for regional regulations
- Document decision-making process
Driving assessment raises important ethical issues:
Autonomy:
- Patients have right to make decisions
- But safety of self and others is paramount
- Need transparent discussion of risks
Confidentiality:
- Assessment results may affect insurance
- Must maintain appropriate confidentiality
- Understand mandatory reporting requirements
Justice:
- Assessment should be accessible
- Not create barriers for underserved populations
- Consider costs and resources
Reporting Requirements:
- Vary by jurisdiction
- Some areas require physician reporting
- Many areas rely on self-reporting
- Portable assessment may enhance monitoring
Licensing:
- Most jurisdictions require periodic renewal
- Medical conditions must be reported
- May require functional assessment
- Appeals process for license revocation
Driving assessment technology continues to evolve:
Virtual Reality (VR):
- More immersive experience with portable devices
- Better engagement and realism
- Costs decreasing rapidly
- Validation studies needed
Smartphone Applications:
- Most accessible option
- Uses phone sensors for basic assessment
- Limited but rapidly improving
- Good for screening, not full assessment
Machine Learning:
- Automated analysis of driving behavior
- Pattern recognition for safety concerns
- May identify subtle warning signs
- Requires validation
Biometric Integration:
- Heart rate variability
- Eye tracking
- Brain-computer interfaces
- May detect fatigue or distraction
Key questions for future investigation:
- Predictive Validity: How well do simulator metrics predict on-road performance?
- Longitudinal Tracking: Can simulators track change over time?
- Intervention Effects: Can simulators measure treatment response?
- Population Norms: What are normal ranges by age and condition?
- Telehealth: Can remote assessment be validated?
Portable simulators could transform care:
Annual Screening:
- Part of routine PD management
- Track changes over time
- Trigger intervention when needed
Pre-Treatment Assessment:
- Baseline before medication changes
- Assess impact of new treatments
- Guide rehabilitation
Rehabilitation Monitoring:
- Track response to driving rehabilitation
- Identify areas for intervention
- Motivate patients with progress data
Hardware Requirements:
- Laptop or tablet computer (12-15 inch minimum)
- Keyboard with arrow keys or basic joystick
- Stable mounting surface
- Quiet environment
Software Requirements:
- Custom driving scenario software
- Data collection and storage
- Basic analytics
- Secure data transfer
Physical Specifications:
- Weight: <5 kg (portable)
- Dimensions: fits in standard case
- Setup time: <10 minutes
- Power: standard electrical outlet
Testing Environment:
- Controlled lighting (not direct sunlight)
- Minimal external distractions
- Comfortable temperature
- Quiet environment
Participant Preparation:
- Review instructions thoroughly
- Practice session (not scored)
- Comfortable seating position
- Correct screen distance/angle
Data Collection:
- Continuous recording of metrics
- Session metadata (time, date, duration)
- Technical issues logged
- Backup data storage
Privacy Considerations:
- HIPAA-compliant storage
- Limited access controls
- Secure transmission protocols
- Data retention policies
Quality Control:
- Automatic range checks on data
- Manual review of outliers
- Inter-rater reliability for subjective metrics
- Regular equipment calibration
| Feature |
Portable |
Fixed (High-Fidelity) |
| Initial Cost |
<$5,000 |
$100,000-500,000 |
| Space Required |
Small |
Dedicated room |
| Setup Time |
<10 min |
30-60 min |
| Portability |
High |
None |
| Visual Fidelity |
2D display |
180°+ immersive |
| Control Fidelity |
Basic keyboard/joystick |
Force-feedback wheel |
| Motion Cues |
None |
3-6 DOF motion |
| Validity for Basic Metrics |
Moderate-high |
High |
| Validity for Complex Scenarios |
Lower |
Higher |
| Feature |
Simulator |
On-Road |
| Standardization |
High |
Variable |
| Safety |
Very high |
Some risk |
| Cost per Assessment |
Low |
High |
| Availability |
Widespread |
Limited |
| Validity |
Good for basic |
Excellent |
| Real-World Transfer |
Moderate |
Excellent |
| Legal Admissibility |
Limited |
Strong |
The validation approach used in this trial may be applicable to other neurological conditions:
Stroke:
- Similar assessment needs
- Different specific impairments
- May benefit from portable monitoring
Multiple Sclerosis:
- Variable disease course
- Fatigue affects driving
- Portable assessment could help
Traumatic Brain Injury:
- Cognitive impairment is key
- Assessment important for return to driving
- Portable tools may assist
Dementia (Non-AD):
- Vascular dementia, Lewy body dementia
- Driving safety concerns
- May benefit from monitoring
Fidelity Constraints:
- Cannot replicate all real-world scenarios
- Limited visual detail
- Missing motion cues
- May not trigger all driving behaviors
Learning Effects:
- Performance improves with practice
- Need adequate washout between sessions
- Repeated testing requires adjustment
Technical Issues:
- Equipment reliability
- Software bugs
- Data quality
- Maintenance requirements
Computer Literacy:
- Some patients unfamiliar with technology
- May affect performance independent of driving ability
- Training may be needed
Physical Limitations:
- Cannot use standard controls
- Visual limitations
- Tremor affecting input devices
Motivation:
- May not take assessment seriously
- Practice effects if motivated
- Fatigue affecting performance
Workflow:
- Training staff on use
- Time in clinic schedule
- Data interpretation
- Reporting to patients
Reimbursement:
- Coverage for assessment
- Billing codes unclear
- May require advocacy
Legal Concerns:
- Documentation standards
- Liability for adverse events
- Reporting requirements