Kinematic Performance in Deep Brain Stimulated Individuals with Parkinson's Disease

Motion Capture Analysis of Subthalamic Nucleus Deep Brain Stimulation in Parkinson's Disease

Dunbar Alcindor MDAllegheny General Hospital12/8/2012

DisclosuresNoneParkinsons Disease (PD) PD is a progressive neurodegenerative disorder associated with a loss of dopaminergic neurons in substantia nigra par compacta.It affects approximately 1% of individuals older than 60 years. Cardinal features include resting tremor, rigidity, bradykinesia, and postural instability.

Parkinsons Disease-TreatmentThe goal of medical management is to provide control of signs and symptoms for as long as possible while minimizing adverse effects. Medications usually provide good symptomatic control of motor signs for 4-6 years. Parkinsons Disease-Treatment-Deep Brain Stimulation (DBS)The subthalamic nucleus (STN) most common site for DBS-PDSTN-DBS has been shown to improve motor activity and ADLThe Unified Parkinsons Disease Rating Scale (UPDRS), most common and well established measurement tool.

The Unified Parkinsons Disease Rating Scale (UPDRS)Total UPDRS consists of four partsParts I, II, and III contains 44 questions each measured on a 5-point scale (0-4). I. Mentation, behavior, and moodII. Activities of daily living (ADL) III. Motor functionIV. Complications of therapy6UPDRS Part III

14 sectionsScore 0-52Symptomatic worsening/improvement can be measured as a change from baselineWorsening of symptoms increases scoreImprovement in symptoms decreases score

7The Unified Parkinsons Disease Rating Scale (UPDRS )UPDRS scale has several limitations:Inherent subjectivity Requires specialized training to administer the test. Early and mild motor disability with PD may not be detected with the UPDRS

8Motion capture in movies, military , sports and medicine AvatarStar wars Pirates of the Caribbean

Motion CaptureMotion capture or mocap is the process of recording the movement of objects or people. It is used in military, entertainment, sports, and medical applications, and for validation of computer vision[1] and robotics. In filmmaking and video game development, it refers to recording actions of human actors, and using that information to animate digital character models in 2D or 3D computer animation. When it includes face and fingers or captures subtle expressions, it is often referred to as performance capture9ObjectiveCan motion capture provide objective measures of a subjects response to DBS treatment for Parkinsons disease?Methods6 Subjects (3M,3F) Idiopathic PD dx 8-16 yrs(mean 11 yrs)Age range 51-67 years (mean 58 yrs)Post DBS-STN 2-5yrs (mean 3.3 yrs)Single surgeon and centerDr. D.M. Whiting, Allegheny General Hospital

Methods-MCKinematic data from 6 subjects (3M/3F) were recorded using a motion capture system consisting of 16 Vicon Vx infrared cameras. The cameras record the 3-dimensional location of 60 reflective markers placed on the participant's body at 120 Hz.

Methods-MCParticipants walked along a walkway(3 meters) at a self selected pace. Medications withheld 12 hours prior to studyPts were assessed with stimulator on and then off30 minutes between testingStudy approved by AGH and CMU IRB

MethodsUPDRS Part III Motor componentTremor- hands and feet Action tremor Hand pronation/supinationGait Arise from chairPostural stabilityLeg agility

MethodsUPDRS Part III Motor componentTremor- hands and feet Action tremor Hand pronation/supinationGait Arise from chairPostural stabilityLeg agility

MethodsUPDRS Part III Motor componentTremor- hands and feet Action tremor Hand pronation/supinationGait Arise from chairPostural stabilityLeg agility

MethodsUPDRS Part III Motor componentTremor- hands and feet Action tremor Hand pronation/supinationGait Arise from chairPostural stabilityLeg agility

MethodsUPDRS Part III Motor componentTremor- hands and feet Action tremor Hand pronation/supinationGait Arise from chairPostural stabilityLeg agility

MethodsUPDRS Part III Motor componentTremor- hands and feet Action tremor Hand pronation/supinationGait Arise from chairPostural stabilityLeg agility

MethodsUPDRS Part III Motor componentTremor- hands and feet Action tremor Hand pronation/supinationGait Arise from chairPostural stabilityLeg agility

Results-UPDRS

UPDRS Scores for 6 subjectsStimulator on and offAverage score On 1.5 and Off 15.3OnOff0170183921123126Results-Gait Analysis

DBS-STN OnStride LengthWalked FasterTasked completed in less time

Blue = Off Green = On Gait :stride length22Results-Gait Analysis

When stepping patterns were assessed, subjects took longer stepsGait :stride length23Results- Gait Analysis

Walked faster and completed their assigned task in less time in the On state3.28ft=1m0.3048m=1ft24Results-GaitOnOffP valueStep Length Mean(mm)4924020.02Speed Mean (mm/sec)7866320.01Step Width Variance (mm)65018970.02MC stepping patters during 3 meter walkCorrelation of UPDRS Part III Motor Scores with DBS in On and Off ConditionOn-Positive Correlation:Step Height VarianceSpeed Variance

Off -Positive Correlation:Step width

The resulting correlation coefficients have values from -1 to 1, where values closer to 1 reflects a strong positive correlation and values closer to -1 strong negative correlation. 26R Wrist acceleration during walking

L Wrist acceleration during walking

Less oscillations, more fluid movement -On Pelvis Accelerations

The pelvis angle(rad) recorded during walking in the Off state was lower and distance between peaks wider for AP and vertical accelerations.

Similar for both in M-L accelerations.

Heel Clearance

Improved heel clearance seen with stimulator OnThis was seen irrespective of R/LPatients were able to raise their feet higherTook less time to raise their feetConclusion

UPDRS correlated when DBS-On for step height and speed, and DBS Off for step widthMC in DBS-STN subjects in On StateImproved heel clearance Wrist: Less oscillations, more fluid movementsPelvis: more control and consistencyIn AP and vertical acceleration during assigned walking taskPatients took less steps, longer strides and completed task in less timeConclusionMC may be utilized to provide a non-invasive and quantifiable method of motor assessment in PD. Our preliminary evidence suggest that MC may be more sensitive to certain motor problems than the UPDRS MC data may someday be used to improve DBS parameter programming.Future Studies-MC and PDHow can we more accurately capture the cardinal symptoms of PDDisease ProgressionOverall effect of treatmentAre there any other subtle signs and symptoms that we can capture to accurately predict disease courseAcknowledgementsAllegheny General Hospital-Division of NeuromodulationDr. D.M. WhitingDr. M.Y. OhDr. N.D. TomyczDr. B. C. Cheng

Allegheny General Hospital-Dept of Neurology-Movement Disorders SectionDr. S. Baser

Carnegie Mellon University- Robotics and Computer Science DepartmentDr. J. HodginsL. TrutoiuAcknowledgements