Ανάλυση βάδισης με το σύστημα RehaWatch

Gait analysis withA novel approach for clinical gait analysis

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Gait analysis with RehaWatch • © Hasomed 2011

Outline

1. Gait analysis− Introduction

− Measurement systems

2. RehaWatch®− System

− Measurement

− Parameter

− Examples

3. Studies

4. Conclusion

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1. Gait analysis – introduction

Gait

− Walking represents the ordinary manner of locomotion

− The human gait is a periodic and reliable cycle and follows basic patterns

− Gait is suitable to evaluate the functionality of the musculoskeletal system

− The gait cycle produces many information over a short time, which an observing person can‘t fully memorize

− Thus, and the necessity of documentation led to the development of instrumented gait analysis

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1. Gait analysis - basics

Situation in European Clinics

− Better - but more expensive treatments of patients are available (new technologies)

− The structure of the society is changing – more elderly persons

− So costs for treatment of patients are increasing dramatically

− Pressure of insurances for quality examination is increasing

− Patients want to get objective information for the results of the treatment – they pay for treatment

− Tools for objective measurements for effects of the treatment are necessary

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Gait analysis is a very important issue in the rehabilitation of

patients with different indications concerning gait

Focus Neurological Rehabilitation− Only in Germany more then 250.000 new patients per year

with stroke – nearly 80% of these patients have disturbances in locomotion

Focus Orthopedic Clinics− Surgery of artificial knees and hips has very increased

Focus Geriatric Clinics

Focus Pediatric Clinics

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3 Phases using objective measurement of locomotion

1. Help to make a decision for a certain kind of treatment (treatment intervention planning)

2. Documentation of results during and at the end of the treatment for insurances and patients

3. Helping to decide whether to continue or to finish a treatment (a pro when talking with the health insurances to extend the treatment)

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How we can describe gait?

− Most popular scheme is published by J. Perry and colleagues of RLARC (California, USA)

Modified by Perry & Burnfield 2010

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Perry & Burnfield 2010, 10

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1. Gait analysis – problems in clinical use

− Visual gait observation underlies verifiable subjective influence. Every people has its own subjective gait.

− During early stages of rehabilitation patients have many abnormalities (e.g. no detection of gait phases is possible)

− Other parameters to quantify gait are necessary

− Gait cycle provides too much information in short time to observe and memorize everything without device

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1. Gait analysis – observation vs. instrumented analysis

− Today in many rehabilitation centers subjective, visual gait observation by physician or therapist is most commonly used. Different scales for observing gait are available (e.g. Tinetti test, 6 Minute Walking Test).

but the results are …

… subjective

… not accurate

… hardly comparable

Therefore objective measurements of the gait are necessary.

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1. Gait analysis – assistive systems

− Over the time different gait assessment systems with different measurement methods were developed:

− 3 D ultrasound systems (e.g. Zebris)

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Optical marker based infrared systems (e.g. Vicon) or video-based systems (e.g. SIMI Motion)

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Such systems are

− Cost intensive (20.000 to >100.000€)

− special laboratory/ room necessary only for gait analysis

− Special education necessary for therapist – no automatic analysis – markers must positioned very exact

− Limited to a small observation area - no independent gait –the results do not show the actual movement

− Mostly connected to a treadmill – no independent gait possible

But : you can document the movement of the whole body

Mostly used in research institutes – not for clinical use

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Foot pressure systems (e.g. Medilogic)

Only a small component of gait is

documented – not movement but

effected pressure

Not used in rehabilitation.

Mostly used for optimization

of orthopedic shoes e.g. for

diabetic patients.

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1. Gait analysis – clinical expectations

What do Clinics need?

Clinical expectations regarding instrumented gait analysis:

− Objective and reliable data

− Fast and easy to use

− Economic

− Possibility of documentation of the treatment

− Therapy supervision

− Verification of therapeutic success

− Use in authentic situations

It should secure and establish high quality in daily gait therapy

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1. Gait analysis - inertial sensor based systems

Therefore a new generation of gait measurement with inertial sensors was developed by the German companyHASOMED GmbHin close cooperation with clinical partners

System

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Outline




− Measurement

− Parameter

− Examples

3. Studies

4. Conclusion

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− RehaWatch is a mobile, inertial sensor based gait analysis system.

− Sensors attached to lateral ankle measure linear acceleration and angle velocity

− Processing raw data leads on− Position of the foot on earth

and at the air

− Gait events,

− Orientation in space

2. RehaWatch - Overview

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2. RehaWatch - Package

− 2 inertial sensors, one for each foot

− Data logger for controlling the measurement and storing the collected data

− foot holds in different sizes

− USB flash drives

− Power supply

− Velcro straps

− Software for PC on CD

− User manual

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− The Easy and fast preparation and operation takes 3-5 minutes only

1. Fix the foot holds to the shoes

2. Sensors mounted with the foot holds

3. Cables fixed with adjustable straps to the legs

4. Data logger fixed with a belt on the back

5. Cables connected to the logger

6. Start measurement

2. RehaWatch – Mounting/ Preparation

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2. RehaWatch - Measurement

Place for Measurement:− Straight, even floor, e.g. clinic corridor

− distance min. of 10m – better 15m2 Markers at the floor

Measurement:

− Start (3s) – walking – stop (3s)

During measurement:

− Patient uses regular but sturdy shoes

− Patient walks with self selected speed

− Allows use of walker or special aid deviceor help from therapists

− The device controls the assessment and guides the user – useable by a nurse or assistant

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2. RehaWatch – Analyse with PC-Software

After Measurement:

− Transfer of measurement data to PC via USB flash device

− Automatic analysis with PC-software− Calculates gait parameters for each step

− Diagrams and visualization of parameters

− Runs on standard Windows-PC and allows full patient and measurement data management

− Export and report functionalities

− Compares the results with norm data of healthy people

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2. RehaWatch - Parameters

− Time and space parameters− Number of steps

− Stride duration

− Stride length

− Cadence

− Velocity

− Gait phases− Loading response, foot flat, pre swing, swing

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− Kinematic parameters− Foot height ->

− Circumduction

− Angle ground-foot

− Special events− Forefeet first, early heel off

− Symmetry− For all bilateral

parameters(e.g. stand phase)

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2. RehaWatch – report

Report for the

documentation

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2. RehaWatch – norm data

− Software includes reference values for comparison measurements data with data of healthy subjects

− Based on 1,860 healthy subjects (data collected together with Prof. Leuchte, Martin-Luther-University Halle-Wittenberg)

− Norm data are in dependency of age, body height and gender Ranges from 5 - 100 years and 1,18m – 2,06m body height

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− Score based on reference values− Allows graphical and customizable one-view assessment in

comparison with healthy subjects

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2. RehaWatch – Therapy progression

− Provides an overview of the therapy progression for each gait parameter

− Values from multiple measurements at different times

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2. RehaWatch – Therapy progression

Progress in symmetry of gait

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2. RehaWatch – Example 1

− 58 years old woman

− Uses walker

− Patient in a neurological rehabilitation center

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− 27 years old man

− Patient in a Chinese clinic

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Outline




− Measurement

− Parameter

− Examples

3. Studies

4. Conclusion

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3. Studies – Reliability/ Reference values

Performed by Prof. Leuchte/ Dr. Schwesig, Martin-Luther University Halle-Wittenberg, Germany

Published in Gait & Posture 33 (2011): „ Inertial sensor based reference gait data for healthy subjects“, pages 673–678

Aim:

− Obtain spatio-temporal gait parameters using a large cohort of healthy persons of all ages and to identify relationships between gait parameters and subject characteristics

− Test of reliability

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3. Studies – Reliability / Reference values

Methods− 1860 healthy subjects, 5-100 years

− Self selected walking speed

− 20m floor walking distance

− Own comfortable shoes

− 3 trials per subject

Results− Large database over complete life span

− Base for RehaWatch reference data

− Allows more precise evaluation of specific gait parameters, not only in comparison to age groups but also at specific time points throughout a person’s life span

− RehaWatch is highly reliable

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3. Studies - Validation

Performed by Prof. Smolenski, Dr. Derlien, University Jena, Germany, Department of Physiotherapy

Published in Manuelle Medizin 2010: „Validation studies for new, innovative gait analysis system RehaWatch from Hasomed”

Aim:

− Validation of RehaWatch in comparison with foot pressure measurement system “MediLogic”

− Does normal or soft floor influence the results?

Methods:

− 51 healthy subjects (21 male, 30 female, age: 25 ± 5 years)

− 15 to 20 steps per measurement with 3 trials each

− Randomized measurement system order

− Normal and soft floor

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3. Studies - Validation

Results− High correlation for spatio-temporal gait parameters

− Pearson-correlation shows good results for normal and soft floor

− Conclusion: “ From our point of view the new gait analysis system RehaWatch® is suitable for monitoring the course in the clinical routine.” (Derlien et al.)

Subjects

Str

ided

ura

tio

n(s

)

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3. Studies - Fatigue measurement

Pilot study „Long term analysis with RehaWatch“ performed by Dr. Röpke, University Magdeburg, Clinic for Orthopedics

Aim:− Determine the time at which the subject/ patients shows changes in

gait-specific parameters

− How can fatigue be identified and evaluated?

Methods:− 12 subjects from a senior sports group (5 male, 7 female,

age: 64,75 64,75 ±± 3,25 years3,25 years)TEP group: 6 subjects with knee or hip TEPTest group: 6 subjects with no orthopedic intervention

− Each subject walks 400m

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Results:− TEP group shows a significantly greater fatigue than the test group

at 400m (left picture)

− Decrease in dependant parameters cadence, stride duration and stride length. Symmetry of gait is different.

Test group TEP group

Minutes

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Outline




− Measurement

− Parameter

− Examples

3. Studies

4. Conclusion

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4. Conclusion – take home messages RehaWatch

− Offers objective and reliable measurement of gait parameters

− Easy and fast to use - measurement including preparation and analysis takes maximum 5 minutes

− Usable everywhere, no specific gait-location necessary (10-15 m clinic floor)

− Further equipment is not necessary (e.g. treadmill)

− No influence on the gait by the system. Very small Sensors. Own shoes can be used.

− Large accumulator capacity for several hours measurements

− Automatic analysis of the data on PC. No special education necessary.

− Patient data compared with norm data

− Important for quality management and documentation of treatment

− Cost effective System

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1. Gait analysis - history

− Gait observation was first described by Aristoteles (384 - 322 BC)

− First steps of scientific gait analysis were done by Boreli(1608 – 1679 AD) with the publication „de motu animalum“

− Modern scientific elaboration of gait mechanisms was formed by the brothers Weber in the 19th century

− Most important milestone was led by Braune & Fischer with the first 3 D movement analysis (early 20th century)

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− Comparison of different measurement methods in relation to the clinical rehabilitation relevance :

SystemFoot

PressureVideoBased

InertialSensor

Optical infrared

Ultrasound

Cost ++ + ++ -- -

Capture volume - -- ++ - --

Accuracy + + + ++ ++

Usability + - ++ -- -

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1. Gait analysis - inertial sensor based systems

That’s why a new generation of gait measurement with inertial sensors was developed from a German company

System

This technology combines the benefits of visual gait monitoring and instrumented gait analysis:

− Provide objective, reliable and exact gait parameters

− No place boundary (e.g. laboratory) – walking 15m on clinic floor

− Easy and time saving to use – 5 minutes

− Expansive equipment is not necessary (e.g. treadmill)

− Large data capacity recording (number of steps)

− If necessary, data can be recorded for up to 2 hours forlong time observation

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2. RehaWatch - Sensors

− Inertial sensors = „use the inertia of mass for detection of motion“

− Each sensor consists of accelerometers and gyroscopes

− Build as MEMS – Technology: electronic and mechanical elements on 1 silicon chip

− 3-axis accelerometer

− 3-axis gyroscope

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3. Studies – Reliabilitation/ Reference values

− RehaWatch is highly reliable

− Pictures below shows regression lines of corrected stride length for men (left side) and women (right side)

Men Women

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4. Conclusion / outlook - Future development directions

− 7-sensor system− Measuring ankle, knee and hip joint

− Primary in sagittal plane, later also in coronal and transverse plane

− Biomechanical model of lower body

− Therapy system− Supplements traditional therapy to recover gait

− Online analysis

− Real time feedback for patients and suggestions for improvement

− Multiple training programs

− Adjustable for each subject

All these future developments are actually possible with RehaWatch

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1. Gait analysis – observation vs. instrumented analysis

− Instrumented gait analysis is traditionally used for surgical applications, rehabilitation and treatment intervention planning, because…

… it provides detailed kinetic and kinematic parameters

… the results are objective

… the systems are reliable

but the application is …

… limited to laboratory use

… cost intensive

… time consuming

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Results:− TEP group shows a significantly greater fatigue than the test group

at 400m (left picture)

− Decrease in dependant parameters cadence, stride duration and stride length

− Test group has less deviationin symmetry (right picture)

Test group TEP group

Minutes

m/s

Ανάλυση βάδισης με το σύστημα RehaWatch

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