Main points of the lecture

Teljes szövegt

(1)

Development of Complex Curricula for Molecular Bionics and Infobionics Programs within a consortial* framework**

Consortium leader

PETER PAZMANY CATHOLIC UNIVERSITY

Consortium members

SEMMELWEIS UNIVERSITY, DIALOG CAMPUS PUBLISHER

The Project has been realised with the support of the European Union and has been co-financed by the European Social Fund ***

**Molekuláris bionika és Infobionika Szakok tananyagának komplex fejlesztése konzorciumi keretben

***A projekt az Európai Unió támogatásával, az Európai Szociális Alap társfinanszírozásával valósul meg.

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Neuromorph Movement Control

Application of biomedical measurements and modeling in medical diagnostics

Neuromorf mozgás szabályozás

(Biomed mérések és modellezés alkalmazása az orvosi diagnosztikában)

József LACZKÓ PhD; Róbert TIBOLD

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Main points of the lecture

The importance of quantitative comparison of healthy and patients suffering from movement disorder

Anatomical planes

Movement disorders and their symptoms

Dystonia

Parkinsonian

Stroke

Case studies on healthy, dystonic and stroke subjects

Upper limb analysis (touching; target tracking)

Gait analysis

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Measured movement patterns of healthy subjects and of patients with neural based movement disorders are quite different.

• One branch of motor control deals with the investigation of variances of healthy movement patterns and variances of pathologic movement patterns.

• Using this method, scientists reveal control principles employed by distinct groups of subjects with different illnesses. These contribute to classification of patients.

• Patients’ neural control usually leads to less movement stability that can be quantitized by the variance of repetitvely excuted motor tasks.

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The importance of quantitative comparison of healthy and pathologic movement patterns

Three-dimensional (3D) motion analysis turned out to be a powerful tool for the quantitative assessment of movements.

• Thanks to several important features:

• non invasive

• within a short period of time measurements can be repeated and evaluated

• provides quantitative and 3D data in kinematics (trajectories, velocity, accelerations, angles),

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The importance of quantitative comparison of healthy and pathologic movement patterns

Kinetics (forces, joint moments, joint powers) Quantitative evaluation of muscle activity (EMG)

Because the comparison of healthy and patients suffering from different movement disorders/disfunctions is a powerful tool:

Thus: quantitative evaluation of motion represents a fundamental tool in human movement analysis.

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Application in different fields such as:

• Clinical applications; kinesiology

Quantitative comparision helps to diagnose movement disorders, e.g. dystonia, Parkinson Disease

It may help to plan the rehabilitation method applied

Thus rehabilitation may focus on the improvement of the precision of movements of individual body parts or on

individual joint rotations, or on improving the cooperation (synergy) of the individual elements.

• Biomechanical studies

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Clinical applications and kinesiology

In clinical applications: the breakthrough of 3D motion analysis is attributed to gait analysis

More precisely: the quantitative analysis of walking

Gait analysis is an important method to represent information:

• Crucial in establishing the level of functional limitation due to a pathology and in following its evolution in time.

• The effect of rehabilitation can be followed, monitored.

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The clinical importance of quantitative motion analysis:

• is demonstrated by the increasing number of laboratories

Clinical applications are used for diagnosing a pathology;

planning of rehabilitation treatment in patients with e.g.:

• Cerebral Palsy (Lee et al., 1992; Gage, 2004).

• Parkinson disease (Keresztenyi et. al.,2009)

• Dystonia

• Other movement disfunctions

(hemiplegics,paraplegics,tetraplegics)

• Multiplex sclerosis

• Down syndrome

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Main anatomical planes in humans

Transverse (horizontal) plane: is an X-Z plane, parallel to the ground.

Coronal (frontal) plane is a Y-X plane, perpendicular to the ground, which separates the anterior from the

posterior.

A sagittal (lateral) plane is an Y-Z plane, perpendicular to the ground, which separates left from right.

Horizontal

Sagittal Frontal

x y

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Dystonia: as a disorder and symptoms of it Dystonia: is a neurological movement disorder,

• in which sustained muscle contractions cause twisting and repetitive movements or abnormal postures.

• The disorder may be hereditary or caused by other factors such as birth-related or other physical trauma, infection, poisoning (e.g., lead poisoning)

or

• reaction to pharmaceutical drugs, particularly neuroleptics

• Treatment is difficult and has been limited to minimizing the symptoms of the disorder, since there is no cure available.

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Parkinson’s disease: as a disorder and symptoms of it

Parkinson's disease (Parkinson's, PD): a degenerative disorder of the central nervous system.

• It is characterized by: muscle rigidity, tremor, postural abnormalities, gait abnormalities, slowing of physical movement (bradykinesia) and a loss of physical movement (akinesia).

Parkinsonian motor control yields higher variability than healthy one .

Healthy motor control may reduce biomechanicallz available number of degrees of freedom by empolying joint-synergies and muscle

synergies.

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Parkinson’s disease: as a disorder and symptoms of it

– Primary symptoms are the results of decreased stimulation of the motor cortex by the basal ganglia.(It involves insufficient

formation and thus action of dopamine produced in the dopaminergic neurons of the midbrain (substantia nigra).

Secondary symptoms include high level cognitive dysfunction and subtle language problems.

Symptoms at the level of the motor system:

– Motor:tremor, rigidity, bradykinesia and postural instability – Neuropsychiatric:cognition, mood and behavior problems

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Stroke as a disorder and symptoms

• Stroke: previously known medically as a cerebrovascular accident (CVA)

It is the rapidly developing loss of brain function(s) due to disturbance in the blood supply to the brain.

This can be due to:

• ischemia (lack of blood flow) caused by blockage (thrombosis, arterial embolism),

• leakage of blood.

Result: the affected area is unable to function, leading to inability to move limbs on one side of the body; inability to understand or

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Comparison of healthy and dystonic patients

• A case study of healthy subjects and patients suffering from dystonia is investigated:

Subjects were asked to perform reaching arm movements:

Reaching an object placed in front of the subject was executed repetitively.

Biomedical measurements were performed

EMG (muscle activities of arm muscles(elbow flexor-extensor)) was recorded

3D joint coordinates were measured to determine joint angles

• Joint angles:

• Intersegmental joint angles: elbow;wrist

Shoulder angle: computed with respect to the frontal plane

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Comparison of healthy and dystonic patients

• Results of the study concerning kinematics and muscle activities are presented in the next 3 slides

• In the left side of these slides: (Healthy)

Angular changes of the shoulder,elbow,wrist

Measured and processed (filtered and smoothed) EMG’s of the

Biceps

Triceps

• In the rigth side of these slides: (Patients with dystonia)

Angular changes of the shoulder,elbow,wrist

Measured and processed (filtered and smoothed) EMG’s of the

Biceps

Triceps

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Angle [o ]

Time [ms]

Shoulder Elbow Wrist

Healthy

1. 2. 3.

t=88

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Angle [o ]

Patient with dystonia

1. 2. 3.

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Movement description based on figures of angular changes

The given motor task: the subjects had to reach an object placed in front of them.

The movement is partitioned into 3 phases:

1. Before touching the object (the time interval lasting from the starting position till touching the object)

2. Touching the object (the time interval between touching the object and releasing it)

3. After touching the object (the time interval elapsed from releasing the object till the arm is returned in the starting position)

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Movement description based on figures of angular changes

It is presented that:

In both healthy and dystonic patients the elbow and the shoulder joints dominate the movement execution.

The changes of elbow and shoulder amplitudes are much higher than the wrist

Dystonic patient started shoulder rotation earlier than elbow rotation.

In contrast, healthy subject started elbow rotation earlier than shoulder rotation. Their neural control employed quite different joint synergies.

Interesting: touching the object interval is not highly effected by the

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Movement description based on figures of angular changes

Other obvious differences between healthy and dystonic patients:

In the dystonic patients no exact touching the object can be discerned in all angular changes

In shouder angle (dystonic subject) there are 2 local maxima opposing to healthy shoulder angle

It is explained by the symptomes of dystonia

In the wrist angle (dystonic patient) local minima’s in 1. and 3. occures when the elbow reached its local minima’s

In dystonic patients the wrist doesn’t have „self motion” it is synchronized with the elbow while in the healthy subject 2 local maximas are present in the wrist angle.

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Healthy Biceps vs. Dystonic Biceps

Healthy Biceps EMG

EMG [mV]

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Healthy Biceps vs. Dystonic Biceps

Patient with dystonia Biceps EMG

EMG [mV]

Time [ms]

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Healthy Triceps vs. Dystonic Triceps

Healthy Triceps EMG

EMG [mV]

t=177

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Patient with dystonia Triceps EMG

EMG [mV]

Time [ms]

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Movement description based on figures of muscle activities

Other obvious differences between healthy and dystonic patients:

In healthy biceps and triceps the flexor and extensor muscles are in different phases

It means: if the flexor reaches its local maxima then the extensor is at a local minima

Such different activity phase is present at t=177 ms

Healthy biceps activity started to increase when the internal elbow angle was decreasing (t=88 ms);

triceps started to reach its top out when the internal elbow

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Such normal behavior is not present in the dystonic subject

Chaotic characteristics are the results of muscle twisting and repetitive movements

Comparion at kinematic level:

Phase diagram of the elbow and shoulder rotations is

presented on the next slide. The motos task was to reach a target and than repose the arm to its initial position

In the case of the healthy subject the relation between the elbow and shoulder angle was very similar in the reaching phase and in the reposing phase of the movement.

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2D joint space (defined by elbow and shoulder angles) in

„touch the object”

movements

Useful: to investigate the the effect of dystonia on elbow- shoulder trajectory

In the dystonic subject the trajectory in the joint space is highly effected by the symptoms

Elbow[o]Elbow[o]

Shoulder [o]

Healthy

Patient with dystonia

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Measured knee and ankle joint angle changes during

one step of a rat and predicted motoneuron pool

activity (discharge rate)

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Human Gait analysis

Healthy and dystonic subjects

• The movement task: the subject had to perform one step.

• 3D coordinates of lower limb joints were recorded in both healthy and dystonic subjects (on their right lower limbs)

• Joint angles of the hip, knee and the ankle were computed

•1 step of the right leg ( stance and swing phases have the same meaning in rats and humans)

with different limb kinematics Hip level

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Gait analysis of healthy and dystonic subjects

Upper panel: the 3 movement phases show normal behavior

Lower panel: The obvious effects of the dystonia (muscle twisting) are present

Angular trajectories are highly effected by the movement disorder

Ankle Knee Hip

Normalized Time Normalized Time Angle[o]Angle[o]

Healthy

Patient with dystonia

Stance Swing

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Target tracking of healthy and stroke patients

The subjects saw a small moving disk on a computer display. They had to follow it with the mouse pointer on the screen controlled by an A/3 size digitizer tablet.

• Two paths were applied(circle and rectangle) and two speed (normal and fast) parameters for the target.

During the movement:

the spatial (3D) position of the subject’s arm

EMG activities of Deltoid anterior, Deltoid posterior, Biceps and Triceps were

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Calculated arm angular changes during the movement of one representative subject from the controlgroup Condition:normal circle

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Calculated arm angular changes during the movement of one representative subject from the patient group Condition:normal circle

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In the control subject: thanks to the task (tracking a given trajectory) in almost all joints except „lower arm rot” and „wrist side” sinusoid angular changes are present

Trajectory = circle

Furthermore: sinusoid muuscle activity patterns were observed

These effects are normal: because the shape of the trajectory to be followed

However, in stroke the patient: the normal sinusoid angular changes and muscle activity patterns are not present

Reason: it is originated from the typical symptoms of stroke as a movement disorder

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Joint & limb angles of stick figure in different gait analysis (rat)

knee ∠

ankle

tip of toe foot

3D mapping of the limb

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Foot contact

Foot contact Swing

Foot lift

“Loading”

swing phase stance phase

A step cycle (stance and swing phase) in the case of a rat

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Summary

• It is really important to deal with 3D motion analysis and the quantitative comparison of healthy subjects and patients (suffering from either movement disfunction or movement disease)

• If we know the symptoms of the movement disorder after executing a series of measurements on both healthy people and patients by doing proper analysis we may be able to understand which „good motor control feature” (healthy motor control) is effected by the disease.

• This information can be applied in planning rehabilitation prosess focusing on the improvement of the discerned dysfuntion.

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Summary (continued)

Then: a proper method for rehabilitation purposes can be defined and applied on the patient

In the lecture: such quantitative comparisons were presented for dystonic, Parkinsonian and stroke patients for both the upper and lower limbs

In all cases: comparisons were performed based on 3D kineamtics and muscle activities

The relation of individual angular changes in te joints of 3-joint systems were presented

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Suggested Literature

Lee E.H., Goh J.C., Bose K. (1992). Value of gait analysis in the assessment of surgery in cerebral palsy.

Arch Phys Med Rehabil. 73 (7): 642-6

Gage J.R. The treatment of gait problems in cerebral palsy. Gage JR editor. London: Cambridge University Press Cambridge University Press (known colloquially as CUP) is a publisher given a Royal Charter by Henry VIII in 1534, and one of the two privileged presses (the other being Oxford University Press);2004

Keresztenyi, Z., Cesari, P., Fazekas, G., Laczko, J. (2009). The relation of hand and arm

configuration variances while tracking geometric figures in Parkinson's disease: aspects for rehabilitation.

International Journal of Rehabilitation Research, 32(1), 53-63.

Thomas T. Warner,Susan B. Bressman, Clinical Diagnosis and Management of Dystonia

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