Driving Performance in Parkinson's Disease and Multiple Sclerosis Using a Driving Simulator

NeuroSimDrive is a prospective observational comparative driving-simulator study designed to characterize driving performance in people with Parkinson's disease and multiple sclerosis using a standardized simulator-based assessment. The study integrates simulator-derived driving data with clinical and functional information already available from previous assessments performed in the participating patient cohorts.

The clinical groups consist of participants with established neurological diagnoses who previously completed psychodiagnostic and screening assessments within an earlier research framework. These pre-existing data include measures of cognitive, attentional, motor, and other functions potentially relevant to driving performance. The simulator study does not use these previous test results as a basis for exclusion; instead, they will be incorporated as explanatory variables when interpreting simulator performance.

A central methodological feature of the study is standardization of the participant's clinical condition at the time of simulator testing. All patients undergo neurological assessment on the day of the simulator session to verify clinical stability and to document factors that could influence driving performance. In participants with multiple sclerosis, disability is characterized using the Expanded Disability Status Scale (EDSS), including relevant functional system scores. In participants with Parkinson's disease, motor status is characterized using the Movement Disorder Society-Unified Parkinson's Disease Rating Scale Part III (MDS-UPDRS III) and Hoehn and Yahr staging. Parkinson's disease participants are assessed during the best practically achievable ON-medication state, with timing of dopaminergic medication and simulator testing documented to improve interpretability of the driving data.

Visual and auditory function are assessed before simulator testing because sensory impairment may affect the validity and interpretation of driving performance. Specialized ophthalmologic assessment, including visual field testing, and audiometric assessment are therefore incorporated into the clinical characterization of the patient groups.

Before the simulator session patients are also screened by Montreal Cognitive Assessment.

The simulator session includes standardized instructions, an adaptation period, and a structured driving scenario. The adaptation period allows participants to become familiar with the simulator controls and virtual environment and provides an opportunity to assess tolerance of the simulation before the evaluated part of the session begins. The expected duration of the simulator component, including instructions and adaptation, is approximately 30 to 60 minutes.

The driving scenario is composed of predefined modules representing common and safety-relevant driving demands. These include baseline driving, lane-changing situations, urban driving, intersections, hazard events, roundabouts, motorway entry, vehicle following, multilane driving, reduced-visibility conditions, and a short repeated module. The same simulator configuration, scenario structure, instructions, and technical conditions are intended to be used across the study groups to maximize comparability.

The simulator continuously records vehicle-control and driving-behavior data, including steering input, pedal use, vehicle speed, lateral position, vehicle trajectory, distance and time relationships to surrounding traffic, and event-related responses. The technical infrastructure may additionally include a camera system, eye tracking, a chest-worn physiological sensor, and a microphone, depending on the final validated study configuration. These additional systems are intended to provide complementary information about visual attention, head and eye movements, selected motor manifestations, physiological responses, and verbal reactions where applicable.

Simulator and sensor data will be time-synchronized and linked to predefined driving segments and events. This allows driving behavior to be examined in relation to the specific demands of each scenario rather than only as an overall session average. Technical validity, completeness of the recording, reasons for interruption, and relevant clinical conditions at the time of testing will be documented for each simulator session.

Healthy control participants are assessed by the technology partner using the same simulator and the same standardized driving scenario under comparable technical and organizational conditions. The control group provides a reference population for interpretation of simulator-derived driving patterns observed in the neurological cohorts.

The study is exploratory and hypothesis-generating in nature. Analyses will focus on group-level differences in simulator-derived driving behavior and on associations between driving performance and clinical, cognitive, motor, and functional characteristics. Additional exploratory analyses may assess whether multimodal data from video, eye tracking, or physiological monitoring provide information beyond conventional simulator telemetry.

Because of the pilot sample size, interpretation will emphasize effect sizes, confidence intervals, feasibility, tolerability, and the consistency of observed performance patterns rather than the establishment of definitive diagnostic thresholds. The study is not designed to provide an individual medical or legal determination of fitness to drive. Simulator findings will be interpreted as research data and not as stand-alone decisions regarding a participant's driving license or medical driving eligibility.

Inclusion criteria

• Age 18 to 85 years.
• Ability to understand study instructions and provide written informed consent.
• Valid driving license for passenger vehicles (Category B or equivalent).
• Active non-professional driving of a motor vehicle.
• Ability to understand the instructions and complete the standardized driving simulator assessment.

For participants with multiple sclerosis:

• Confirmed diagnosis of multiple sclerosis according to applicable diagnostic criteria.
• Expanded Disability Status Scale (EDSS) score less than 6.5.
• Clinically stable disease at the time of simulator assessment.
• At least 6 weeks since the most recent multiple sclerosis relapse and any corticosteroid treatment for relapse.
• Previous completion of the psychodiagnostic and screening assessment used in the preceding OP-JAK research framework (NCT07360886) within 6 months before simulator testing, provided that no clinically relevant deterioration has occurred.
• Completion of the required neurological, ophthalmological, visual-field, and audiometric assessments before or on the day of simulator testing, as specified by the study protocol.

For participants with Parkinson's disease:

• Confirmed diagnosis of idiopathic Parkinson's disease.
• Hoehn and Yahr less than stage IV in the ON-medication state.
• Clinically stable condition at the time of simulator assessment.
• Ability to undergo simulator testing during the best practically achievable ON-medication state.
• Previous completion of the psychodiagnostic and screening assessment used in the preceding OP-JAK research framework within 6 months before simulator testing, provided that no clinically relevant deterioration has occurred.
• Completion of the required neurological, ophthalmological, visual-field, and audiometric assessments before or on the day of simulator testing, as specified by the study protocol.

For healthy control participants:

• No known neurological disorder expected to substantially affect driving performance.
• Self-reported current health status compatible with safe completion of the driving simulator assessment.
• Visual and auditory function, with usual correction if applicable, sufficient to safely and validly complete the simulator assessment.

Exclusion criteria

• Acute medical or neurological deterioration that would prevent safe or valid completion of the driving simulator assessment.
• Current intoxication with alcohol or other psychoactive substances.
• Marked sleep deprivation, excessive fatigue, or another temporary condition that, in the judgment of the responsible study personnel, would substantially impair the ability to complete testing safely and validly.
• Severe simulator sickness or current vestibular symptoms that prevent completion of simulator testing.
• Clinically significant uncorrected visual or auditory impairment that prevents valid completion of the simulator assessment.

Inability to understand study instructions or safely operate the driving simulator.

• Withdrawal of consent or refusal of data recording required for the study when no technically valid alternative method is available.

Additional exclusion criteria for participants with multiple sclerosis:

• Current multiple sclerosis relapse.
• Less than 30 days since the most recent relapse or corticosteroid treatment for relapse.
• EDSS score > 6.5.

Additional exclusion criteria for participants with Parkinson's disease:

• Atypical parkinsonian syndrome.
• Hoehn and Yahr stage > 4 in the ON-medication state.
• Deep brain stimulation in the main Parkinson's disease cohort.
• Clinical condition preventing testing during a sufficiently stable ON-medication period.

Additional exclusion criteria for healthy control participants:

• Self-reported neurological disease or other health condition expected to substantially influence cognitive, sensory, or motor functions relevant to driving.
• Current psychiatric or medical condition that would prevent safe or valid completion of the simulator assessment.
• Current use of substances or medications producing an acute level of impairment incompatible with safe simulator testing.