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Dear Colleagues,
Few weeks ago, I made an inquiry about the possibility of un-assisted
standing up in paraplegics. I would like to thank all of you who answered
and those who took your time to think about the problem.
In brief:
Megan questions the necessity of un-assisted standing up and its
justification by mentioning the extensive sensory requirements and the
difficulty of coordinating voluntary movements with postural strategies.
Chris thinks hybrid systems and closed loop control are needed for
maintaining stance for reasonable time.
Thomas mentions AutoMove for stroke victims that may not be applicable for
paraplegics with damaged neural pathways.
Fariba confirms the importance of arms in paraplegic standing by
explaining their experience.
Some of the practical problems requiring arm assistance are discussed by
June Akers.
It seems that Michael believes in the possibility of un-assisted standing
up. He sent me an interesting discussion on the subject that has also
appeared in his Ph.D. thesis. The complete discussion is included here.
Thank you all - Very merry Christmas and happy holidays
Best wishes
Rahman Davoodi
*-------------------------------------------------*
| Rahman Davoodi |
| Department of Biomedical Engineering |
| 10-102 Clinical Science Building |
| University of Alberta |
| Edmonton, Canada T6G 2G3 |
| |
| Ph: (403)492-0723 Fax: (403)492-8259 |
| E-mail: Rahman.Davoodi@ualberta.ca |
| http://www.ualberta.ca/~rdavoodi/davoodi.html |
*-------------------------------------------------*
The following is the original message followed by the responses:
=============================================
Dear Colleagues,
I am involved in modeling and control of arm-supported standing up in
paraplegics. As part of our study we are evaluating the possibility of
un-assisted standing up and its limitations as related to issues such as
control strategies, required and available joint torque produced by
electrical stimulation and so on.
I would like to have your opinions about:
1. The possibility of un-assisted standing up
2. The reasons if you think it is impossible
3. The requirements if you think it is possible
I will send a summary to the list.
Regards
Rahman Davoodi
-----------------------------------------------------------------------------
My first question to you is: Why do you think it is necessary
to provide unassisted standing up? In other words, how often
is it necessary for a paraplegic person to stand; what percent
of those times does standing need to be unassisted; and does
the "benefit" (of being able to stand up unassisted) outweigh
the "costs" of carting around all the sensors that will be
required to make this happen?
Second, as has been discussed on this listserver before,
voluntary movements (like standing up) are both feed-forward
(requiring trajectory planning and maintaining posture and
balance simultaneously) and feedback (correcting for
disturbances in trajectory along the way). How will you
coordinate (or account for) the voluntary movements and
postural strategies of the person's un-paralyzed upper body?
To your sensors, these voluntary movements of the upper body
will "look" like external disturbances--even if they serve an
important postural role.
Those are my thoughts.
-Megan Moynahan
E-mail: MBM@FDADR.CDRH.FDA.GOV
-----------------------------------------------------------------------------------------
Rahman,
You might be interested in a study we've just done on the Clinical Gait
Analysis email list and web-site. You'll find it at:
http://www.curtin.edu.au/curtin/dept/physio/pt/staff/kirtley/cga/teach-in
It should give you some idea of the likely muscle moments and powers
you'll need to generate with your FES. We did quite a bit of work on
standing with FES when I was at Strathclyde in the mid-'80s. In the end we
used hybrid AFOs, with a closed-loop controller to conserve quads
stimulation (using it only when the patient was in an unstable state, with
Ground Reaction Vector in front of the knee). Basically, this is the only
chance you have of
maintaining stance for a reasonable time, as otherwise the quads just
fatigue within a few seconds. You need to mimic the physiological phasic
action of the quads, just restoring passive stability by using the GRV.
Best wishes,
Chris
__________________________________________________ __________________
DDr. Chris Kirtley MB ChB, PhD c.kirtley@info.curtin.edu.au
Department of Biomechanics
University of Vienna
Auf der Schmelz, 6
A-1150 Vienna tel +43-1-9822661-232
Austria fax +43-1-9822661-277
WWW: http://www.curtin.edu.au/curtin/dept/physio/pt/staff/kirtley
Clinical Gait Analysis: website with clinical cases, data & FAQ:
http://www.univie.ac.at/cga &
http://www.curtin.edu.au/curtin/dept/physio/pt/staff/kirtley/cga
Internet Relay Chat: irc.curtin.edu.au (port 6667) "bio-engineering"
-----------------------------------------------------------------------------------------
Dear Sir,
Have you heard about the AutoMove, a device that combines NMES with EMG
especially for stroke rehab ?
The AutoMove has helped thousands of stroke victims in Germany, Japan,
Hong Kong, etc. to gain control over paralyzed extremities by COGNITIVE
RELEARNING.
The NMES assists the central nervous system to identify the correct parts
of the brain to use, while the EMG is a biofeedback that rewards the
patient for trying hard hard enough to fire neurons to the right muscle
groups. The
ultimate biofeedback is to have the patient experience that what he is
trying to do actually happens (e.g. thinking very hard about moving the
hand, and when he sends enough neurons he will actually see the hand
moving
(NMES).
If you are interested I shall be happy to fax or mail you copies of
clinical studies on this unique equipment. Perhaps you also know of other
people that are interested in hearing about these little "miracles".
Best regards, Thomas Sandgaard
E-mail: sandgaar@post4.tele.dk
-----------------------------------------------------------------------------------------
Dear Mr. Davoodi,
I have received last week your email distributed through
BIOMECH-LIST. I have also read the two abstractes about your
work in proceedings of IEEE, EMBS 96. I am working in
collaboration with a group of neurologists and engineers .
I am doing my research since two years ago at the Institute
of Automatic Control in Technical university of Munich
as a guest Ph.D student, and my research thema is exactely
the same as yours.
Recentely we have done a series of measurements during standing up
and sitting down on healthy subjects and paraplegic patients (with
and without electrical stimulation), and have collected the
kinematic and kinetic data.
According to the preliminary results both groups use their arm
during the movement to coordinate the motion of their upperbody
with their lower extremities (the measured hand reaction
forces and calculated shoulder loads support this idea).
I believe that (as you have mentioned in your work
in EMBS's meeting) arms have an indispensable function during
standing up in patients( moving with or without FES) which
must be integrated in our modeling process. For example in
patients with two channel FES, they transfer their weight
to their feet first after reaching a stable standing posture,
and it is not even for all subjects possible.
I have also some questions about the model you introduced in your
abstract: as you have mentioned the model has 5 segments, and
you control the shoulder loads with a fuzzy controller.
What is the role of 2-segmental arm in your model, and do
you use a 2D model for it?
With best regards
Fariba Bahrami
E-mail: bahrami@ventura.lsr.e-technik.tu-muenchen.d
===================
Dear Mrs. Bahrami,
I tried several times to answer your questions by sending emails but all
of them were returned. Please let me know if you have another E-mail
address.
Best wishes
Rahman
===================
-----------------------------------------------------------------------------------------
NOT SURE IF THIS WILL HELP BUT....
THERE WAS A RESEARCH STUDY BEING DONE AT MCGILL ON FES AND WALKING WITH
PARAPLEGIC SUBJECTS (NOT SURE IF THEY HAD COMPLETE OR INCOMPLETE
INJURIES). I
BELIEVE THE PROFESSOR INVOLVED WAS DR.BARBEAU (NOW AT UNIVERSITE DE
MONTREAL?)
AND I THINK ONE OF THE MASTERS STUDENTS WAS ELLEN MELLIS (NOW AT OTTAWA U.
E-MAIL ADDRESS IS EMELIS@AIX1.UOTTAWA.CA). HOPE THIS IS OF SOME USE,
MARIE
E-mail: MARIE.HISCOCKS@centrahealth.com
-----------------------------------------------------------------------------------------
Dear Rahman,
We, too, use FES to assist those with paraplegia to stand up. I am a
biomedical engineer who assists in the programming of the patterns of
FES delivery to the muscles. From speaking with our physical therapist,
Dan Bonaroti, and from my own personal observations, I can offer some
insights and opinions.
Both of our two largest subjects (late teen males, > 6 ft. tall), have
to give a good deal of upper extremity assistance in rising from the
chair because of insufficient power generation from the knee extensors --
we use Vastus Lateralis and Vastus Medius with percutaneous electrodes.
One of our smaller, lighter subjects (a 12 yr old male) prefers to allow
the FES to put his legs into extension BEFORE getting up from the chair.
This is primarily because the initiation of stimulation triggers spasms
which subside after a few moments. These spasms would make rising from
the chair difficult with their variability and resistance to hip
extension.
Most of our patients have lateral hip instability during rising.
We use the Gluteus Maximus and Gluteus Medius during standing to give
hip extension and stability, but we only use the G. Maximus during the
very end of the rising phase preceding standing. Perhaps the G.Med.
should be used during rising to keep the hips from wobbling out to
the sides? Perhaps there are other lateral control muscles that can
achieve this?
Our FES is currently an open-loop system. Perhaps a closed-loop system
would be able to adjust for the day-to-day, stand-to-stand variations in
FES-controlled muscle output and the output of the voluntary (trunk and
other upper-body) output.
You certainly have your work cut out for you. Please keep us posted
on how it's going!
June Akers
Research Department
Shriners Hospital for Children
8400 Roosevelt Blvd.
Philadelphia, PA 19152
(215) 332-4500 email: akers@astro.ocis.temple.edu
-----------------------------------------------------------------------------------------
Extract from:
"Restoration and Biomechanical Evaluation of Standing Up and Sitting Down
in Paraplegics using Functional Electrical Stimulation"
by Michael John Dolan, PhD Thesis, University of Strathclyde.
Unaided FES-assisted Stand-sit Manoeuvres:
An interesting question that is related to the work reported here and
which is, perhaps, crucially important to the future practical application
of FES-assisted standing and walking is: Can FES-assisted standing up and
sitting down be achieved unaided by the upper limbs? To achieve
unsupported FES-assisted standing up and sitting down two goals must be
achieved: (1) sufficiently large muscle contractions must be elicited to
physically lift and lower the user, and (2) the manoeuvres must be
adequately controlled since the upper limbs will not be able to correct
for any sway.
In the studies reported here all three subjects were able to
stand up and sit down with the assistance of FES. However,
during standing up all three subjects relied heavily on upper
limb support to lift themselves upwards (as indicated most
directly by the large vertical forces) and to stabilise themselves
(as shown by the forces in the horizontal plane). During sitting
down these factors would appear to be less critical since a user
would be moving into a stable position, though it would of course
still be important that seat contact was controlled.
Rodosky and co-workers (1989) reported maximum hip and knee
extension moments during standing up to be between 9 and
10% BWheight, and 4 and 5% BWheight respectively. So for
example, someone with weight 800 N and height 1.8 m would have
a maximum hip moment of around 135 N m and a knee moment of around
65 N m. Kotake and co-workers (1993) reported the minimum
theoretical extension moment per body mass in kilograms required
to stand up to be 0.7 N m kg-1 for the hip and 0.9 N m kg-1 for
the knee. So for example, a 80 kg person would need to produce
moments of 56 N m about hip and 72 N m about knee. These two
studies and the reported parameters differ, but there is
nevertheless good agreement between the knee extension moments
required for standing up. The hip extension moments do, however,
differ quite considerably. Rodoskys subjects were young adults
who might be expected to have a quite dynamic ascent requiring
more than the minimum hip extension moment, whilst Kotakes
attempted to find the minimum required for elderly subjects to
stand up. In respect of FES-assisted standing up Kotakes values
may therefore be the most appropriate indicators of the extensor
moments that must be generated in order to achieve standing up
without upper limb support.
The maximum knee extensor moment achieved by subject A was
57.8 N m, while subject B achieved 70.1 N m (table 7.1). Other
studies have reported achieving knee extensor moments of similar
magnitudes, for example, Marsolais & Kobetic (1983) reported that
a myelitis subject achieved around 50 N m isokinetically (60 s-1)
after eight months training, and Carroll and co-workers (1989)
achieved isometric moments of up to 91 N m with two well-trained
paraplegic subjects. Both of these studies used percutaneous
electrodes. The results of this study and other reports
demonstrate that the knee moment required to stand up unaided
(around 70 N m) is a realistic target.
The hip extensors were not recruited in the study and the strength
of these muscles was not evaluated. Brindley and co-workers
(1978) reported that with the same degree of training and
stimulation frequency the extensor moment at the hip never
exceeded one-tenth of the knee extensor moment, and that it
was not sufficient to prevent the interruption of walking by
episodes of hip flexion. The actual hip and knee extensor moments
were not reported though the knee forces up to 30 kg were measured
(though the point of measurement was not stated). These results
were obtained using an implanted system with cuff electrodes
around the femoral nerves and inferior gluteal nerves. Although,
the hip extensors have been recruited in many other FES studies,
the author is not aware of any studies that have reported the
magnitude of the hip extension moments that were achieved using
electrical stimulation. The amount of hip extensor strength that
can be elicited clearly needs further evaluation.
Provided there is sufficient muscle strength the next goal must
be to adequately control the two manoeuvres to minimise the amount
of sway. Standing up in the young and able-bodied is a very
dynamic movement with the upper body being thrust forward to
generate forward and upward momentum, and once standing is
achieved a period of stabilisation is required. More elderly
subjects will tend to stand up less dynamically. A less dynamic
ascent can minimise the magnitudes of the moments about the lower
limbs (Wheeler et al., 1985; Pai & Rogers, 1991), an advantage
for FES-assisted standing up, but will extend the duration of
the manoeuvre and therefore requiring more muscle activity. The
latter is only a disadvantage for FES-assisted standing up, if
several stand-sit manoeuvres need to be performed in a short
period of time. The initial body position can also be an
important factor (see section 2.1.1.5). Sitting down must also
be controlled. In particular the force with which the user
contacts the seat is important so as to avoid injury.
The discussion above has assumed that the techniques used to
achieve standing up and sitting would be the same as those
employed by able bodied subjects. However, it has long been
known that simply placing the hands on the knees can help those
with weak lower limb muscles (Gowers, 1879) (presumably by
providing an extending moment about the hip) and other techniques
have been adopted by those suffering from neuromuscular weakness
(Butler et al., 1991). These need to be considered further.
Doorenbosch and co-workers (1994) also demonstrated that the joint
moments are dependent to some extent on the technique employed
to stand up. It could be envisaged that a FES user could use
their upper arms to assist their standing up and sitting down,
but without a standing frame, by placing their hands on their
seat or its armrests during the initial or later periods of the
standing up and sitting down respectively, or by placing their
hands on their knees, to compensate for muscle weakness.
References:
Brindley GS, Polkey CE & Rushton DN (1978) Electrical splinting
of the knee in paraplegia. Paraplegia 16:428-435.
Butler PB, Nene AV & Major RE (1991) Biomechanics of transfer
from sitting to the standing postion in some neuromuscular
diseases. Physiotherapy 77(8):521-525.
Carroll SG, Triolo RJ, Chizeck HJ, Kobetic R & Marsolais EB
(1989) Teteanic responses of electrically stimulated paralyzed
muscle at varying interpulse intervals. IEEE Trans Biomed
Eng BME-36(7):644-653.
Doorenbosch CAM, Harlaar J, Roebroeck ME & Lankhorst GJ (1994)
Two strategies of transferring from sit-to-stand; activation of
monoarticular and biarticular muscles. J Biomech 27:1299-1307.
Gowers WR (1879) Pseudo-hypertrophic Muscular Paralysis: A
Clinical Lecture. J & A Churchill, London.
Kotake T, Dohi N, Kajiwara T, Sumi N, Koyama Y & Miura T (1993)
An analysis of sit-to-stand movements. Arch Phys Med Rehabil
74:1095-1099.
Marsolais EB & Kobetic R (1983) Functional walking in paralyzed
patients by means of electrical stimulation. Clinical
Orthopaedics & Related Research 175:30-6.
Pai YC & Rogers MW (1991) Speed variation and resultant joint
torques during sit-to-stand. Arch Phys Med Rehabil 72:881-885.
Rodosky MW, Andriacchi TP & Andersson GBJ (1989) The influence of
chair height on lower limb mechanics during rising. J Orthopaedic
Research 7(2):266-271.
Wheeler J, Woodward C, Ucovich RL, Perry J & Walker JM (1985)
Rising from a chair: Influence of age and chair design. Physical
Therapy 65(1): 22-26.
Michael J. Dolan, Lecturer in Biomedical Engineering,
Dept. Orthopaedic and Trauma Surgery, Fleming Building
University of Dundee, Dundee DD1 4HN, Scotland, U.K.
Tel: ++ 44 (0)1382 344642 Fax: ++ 44 (0)1382 344644
E-mail: m.j.dolan@dundee.ac.uk
www: http://www.dundee.ac.uk/orthopaedics/mjdolan
---------------------------------------------------------------------
Few weeks ago, I made an inquiry about the possibility of un-assisted
standing up in paraplegics. I would like to thank all of you who answered
and those who took your time to think about the problem.
In brief:
Megan questions the necessity of un-assisted standing up and its
justification by mentioning the extensive sensory requirements and the
difficulty of coordinating voluntary movements with postural strategies.
Chris thinks hybrid systems and closed loop control are needed for
maintaining stance for reasonable time.
Thomas mentions AutoMove for stroke victims that may not be applicable for
paraplegics with damaged neural pathways.
Fariba confirms the importance of arms in paraplegic standing by
explaining their experience.
Some of the practical problems requiring arm assistance are discussed by
June Akers.
It seems that Michael believes in the possibility of un-assisted standing
up. He sent me an interesting discussion on the subject that has also
appeared in his Ph.D. thesis. The complete discussion is included here.
Thank you all - Very merry Christmas and happy holidays
Best wishes
Rahman Davoodi
*-------------------------------------------------*
| Rahman Davoodi |
| Department of Biomedical Engineering |
| 10-102 Clinical Science Building |
| University of Alberta |
| Edmonton, Canada T6G 2G3 |
| |
| Ph: (403)492-0723 Fax: (403)492-8259 |
| E-mail: Rahman.Davoodi@ualberta.ca |
| http://www.ualberta.ca/~rdavoodi/davoodi.html |
*-------------------------------------------------*
The following is the original message followed by the responses:
=============================================
Dear Colleagues,
I am involved in modeling and control of arm-supported standing up in
paraplegics. As part of our study we are evaluating the possibility of
un-assisted standing up and its limitations as related to issues such as
control strategies, required and available joint torque produced by
electrical stimulation and so on.
I would like to have your opinions about:
1. The possibility of un-assisted standing up
2. The reasons if you think it is impossible
3. The requirements if you think it is possible
I will send a summary to the list.
Regards
Rahman Davoodi
-----------------------------------------------------------------------------
My first question to you is: Why do you think it is necessary
to provide unassisted standing up? In other words, how often
is it necessary for a paraplegic person to stand; what percent
of those times does standing need to be unassisted; and does
the "benefit" (of being able to stand up unassisted) outweigh
the "costs" of carting around all the sensors that will be
required to make this happen?
Second, as has been discussed on this listserver before,
voluntary movements (like standing up) are both feed-forward
(requiring trajectory planning and maintaining posture and
balance simultaneously) and feedback (correcting for
disturbances in trajectory along the way). How will you
coordinate (or account for) the voluntary movements and
postural strategies of the person's un-paralyzed upper body?
To your sensors, these voluntary movements of the upper body
will "look" like external disturbances--even if they serve an
important postural role.
Those are my thoughts.
-Megan Moynahan
E-mail: MBM@FDADR.CDRH.FDA.GOV
-----------------------------------------------------------------------------------------
Rahman,
You might be interested in a study we've just done on the Clinical Gait
Analysis email list and web-site. You'll find it at:
http://www.curtin.edu.au/curtin/dept/physio/pt/staff/kirtley/cga/teach-in
It should give you some idea of the likely muscle moments and powers
you'll need to generate with your FES. We did quite a bit of work on
standing with FES when I was at Strathclyde in the mid-'80s. In the end we
used hybrid AFOs, with a closed-loop controller to conserve quads
stimulation (using it only when the patient was in an unstable state, with
Ground Reaction Vector in front of the knee). Basically, this is the only
chance you have of
maintaining stance for a reasonable time, as otherwise the quads just
fatigue within a few seconds. You need to mimic the physiological phasic
action of the quads, just restoring passive stability by using the GRV.
Best wishes,
Chris
__________________________________________________ __________________
DDr. Chris Kirtley MB ChB, PhD c.kirtley@info.curtin.edu.au
Department of Biomechanics
University of Vienna
Auf der Schmelz, 6
A-1150 Vienna tel +43-1-9822661-232
Austria fax +43-1-9822661-277
WWW: http://www.curtin.edu.au/curtin/dept/physio/pt/staff/kirtley
Clinical Gait Analysis: website with clinical cases, data & FAQ:
http://www.univie.ac.at/cga &
http://www.curtin.edu.au/curtin/dept/physio/pt/staff/kirtley/cga
Internet Relay Chat: irc.curtin.edu.au (port 6667) "bio-engineering"
-----------------------------------------------------------------------------------------
Dear Sir,
Have you heard about the AutoMove, a device that combines NMES with EMG
especially for stroke rehab ?
The AutoMove has helped thousands of stroke victims in Germany, Japan,
Hong Kong, etc. to gain control over paralyzed extremities by COGNITIVE
RELEARNING.
The NMES assists the central nervous system to identify the correct parts
of the brain to use, while the EMG is a biofeedback that rewards the
patient for trying hard hard enough to fire neurons to the right muscle
groups. The
ultimate biofeedback is to have the patient experience that what he is
trying to do actually happens (e.g. thinking very hard about moving the
hand, and when he sends enough neurons he will actually see the hand
moving
(NMES).
If you are interested I shall be happy to fax or mail you copies of
clinical studies on this unique equipment. Perhaps you also know of other
people that are interested in hearing about these little "miracles".
Best regards, Thomas Sandgaard
E-mail: sandgaar@post4.tele.dk
-----------------------------------------------------------------------------------------
Dear Mr. Davoodi,
I have received last week your email distributed through
BIOMECH-LIST. I have also read the two abstractes about your
work in proceedings of IEEE, EMBS 96. I am working in
collaboration with a group of neurologists and engineers .
I am doing my research since two years ago at the Institute
of Automatic Control in Technical university of Munich
as a guest Ph.D student, and my research thema is exactely
the same as yours.
Recentely we have done a series of measurements during standing up
and sitting down on healthy subjects and paraplegic patients (with
and without electrical stimulation), and have collected the
kinematic and kinetic data.
According to the preliminary results both groups use their arm
during the movement to coordinate the motion of their upperbody
with their lower extremities (the measured hand reaction
forces and calculated shoulder loads support this idea).
I believe that (as you have mentioned in your work
in EMBS's meeting) arms have an indispensable function during
standing up in patients( moving with or without FES) which
must be integrated in our modeling process. For example in
patients with two channel FES, they transfer their weight
to their feet first after reaching a stable standing posture,
and it is not even for all subjects possible.
I have also some questions about the model you introduced in your
abstract: as you have mentioned the model has 5 segments, and
you control the shoulder loads with a fuzzy controller.
What is the role of 2-segmental arm in your model, and do
you use a 2D model for it?
With best regards
Fariba Bahrami
E-mail: bahrami@ventura.lsr.e-technik.tu-muenchen.d
===================
Dear Mrs. Bahrami,
I tried several times to answer your questions by sending emails but all
of them were returned. Please let me know if you have another E-mail
address.
Best wishes
Rahman
===================
-----------------------------------------------------------------------------------------
NOT SURE IF THIS WILL HELP BUT....
THERE WAS A RESEARCH STUDY BEING DONE AT MCGILL ON FES AND WALKING WITH
PARAPLEGIC SUBJECTS (NOT SURE IF THEY HAD COMPLETE OR INCOMPLETE
INJURIES). I
BELIEVE THE PROFESSOR INVOLVED WAS DR.BARBEAU (NOW AT UNIVERSITE DE
MONTREAL?)
AND I THINK ONE OF THE MASTERS STUDENTS WAS ELLEN MELLIS (NOW AT OTTAWA U.
E-MAIL ADDRESS IS EMELIS@AIX1.UOTTAWA.CA). HOPE THIS IS OF SOME USE,
MARIE
E-mail: MARIE.HISCOCKS@centrahealth.com
-----------------------------------------------------------------------------------------
Dear Rahman,
We, too, use FES to assist those with paraplegia to stand up. I am a
biomedical engineer who assists in the programming of the patterns of
FES delivery to the muscles. From speaking with our physical therapist,
Dan Bonaroti, and from my own personal observations, I can offer some
insights and opinions.
Both of our two largest subjects (late teen males, > 6 ft. tall), have
to give a good deal of upper extremity assistance in rising from the
chair because of insufficient power generation from the knee extensors --
we use Vastus Lateralis and Vastus Medius with percutaneous electrodes.
One of our smaller, lighter subjects (a 12 yr old male) prefers to allow
the FES to put his legs into extension BEFORE getting up from the chair.
This is primarily because the initiation of stimulation triggers spasms
which subside after a few moments. These spasms would make rising from
the chair difficult with their variability and resistance to hip
extension.
Most of our patients have lateral hip instability during rising.
We use the Gluteus Maximus and Gluteus Medius during standing to give
hip extension and stability, but we only use the G. Maximus during the
very end of the rising phase preceding standing. Perhaps the G.Med.
should be used during rising to keep the hips from wobbling out to
the sides? Perhaps there are other lateral control muscles that can
achieve this?
Our FES is currently an open-loop system. Perhaps a closed-loop system
would be able to adjust for the day-to-day, stand-to-stand variations in
FES-controlled muscle output and the output of the voluntary (trunk and
other upper-body) output.
You certainly have your work cut out for you. Please keep us posted
on how it's going!
June Akers
Research Department
Shriners Hospital for Children
8400 Roosevelt Blvd.
Philadelphia, PA 19152
(215) 332-4500 email: akers@astro.ocis.temple.edu
-----------------------------------------------------------------------------------------
Extract from:
"Restoration and Biomechanical Evaluation of Standing Up and Sitting Down
in Paraplegics using Functional Electrical Stimulation"
by Michael John Dolan, PhD Thesis, University of Strathclyde.
Unaided FES-assisted Stand-sit Manoeuvres:
An interesting question that is related to the work reported here and
which is, perhaps, crucially important to the future practical application
of FES-assisted standing and walking is: Can FES-assisted standing up and
sitting down be achieved unaided by the upper limbs? To achieve
unsupported FES-assisted standing up and sitting down two goals must be
achieved: (1) sufficiently large muscle contractions must be elicited to
physically lift and lower the user, and (2) the manoeuvres must be
adequately controlled since the upper limbs will not be able to correct
for any sway.
In the studies reported here all three subjects were able to
stand up and sit down with the assistance of FES. However,
during standing up all three subjects relied heavily on upper
limb support to lift themselves upwards (as indicated most
directly by the large vertical forces) and to stabilise themselves
(as shown by the forces in the horizontal plane). During sitting
down these factors would appear to be less critical since a user
would be moving into a stable position, though it would of course
still be important that seat contact was controlled.
Rodosky and co-workers (1989) reported maximum hip and knee
extension moments during standing up to be between 9 and
10% BWheight, and 4 and 5% BWheight respectively. So for
example, someone with weight 800 N and height 1.8 m would have
a maximum hip moment of around 135 N m and a knee moment of around
65 N m. Kotake and co-workers (1993) reported the minimum
theoretical extension moment per body mass in kilograms required
to stand up to be 0.7 N m kg-1 for the hip and 0.9 N m kg-1 for
the knee. So for example, a 80 kg person would need to produce
moments of 56 N m about hip and 72 N m about knee. These two
studies and the reported parameters differ, but there is
nevertheless good agreement between the knee extension moments
required for standing up. The hip extension moments do, however,
differ quite considerably. Rodoskys subjects were young adults
who might be expected to have a quite dynamic ascent requiring
more than the minimum hip extension moment, whilst Kotakes
attempted to find the minimum required for elderly subjects to
stand up. In respect of FES-assisted standing up Kotakes values
may therefore be the most appropriate indicators of the extensor
moments that must be generated in order to achieve standing up
without upper limb support.
The maximum knee extensor moment achieved by subject A was
57.8 N m, while subject B achieved 70.1 N m (table 7.1). Other
studies have reported achieving knee extensor moments of similar
magnitudes, for example, Marsolais & Kobetic (1983) reported that
a myelitis subject achieved around 50 N m isokinetically (60 s-1)
after eight months training, and Carroll and co-workers (1989)
achieved isometric moments of up to 91 N m with two well-trained
paraplegic subjects. Both of these studies used percutaneous
electrodes. The results of this study and other reports
demonstrate that the knee moment required to stand up unaided
(around 70 N m) is a realistic target.
The hip extensors were not recruited in the study and the strength
of these muscles was not evaluated. Brindley and co-workers
(1978) reported that with the same degree of training and
stimulation frequency the extensor moment at the hip never
exceeded one-tenth of the knee extensor moment, and that it
was not sufficient to prevent the interruption of walking by
episodes of hip flexion. The actual hip and knee extensor moments
were not reported though the knee forces up to 30 kg were measured
(though the point of measurement was not stated). These results
were obtained using an implanted system with cuff electrodes
around the femoral nerves and inferior gluteal nerves. Although,
the hip extensors have been recruited in many other FES studies,
the author is not aware of any studies that have reported the
magnitude of the hip extension moments that were achieved using
electrical stimulation. The amount of hip extensor strength that
can be elicited clearly needs further evaluation.
Provided there is sufficient muscle strength the next goal must
be to adequately control the two manoeuvres to minimise the amount
of sway. Standing up in the young and able-bodied is a very
dynamic movement with the upper body being thrust forward to
generate forward and upward momentum, and once standing is
achieved a period of stabilisation is required. More elderly
subjects will tend to stand up less dynamically. A less dynamic
ascent can minimise the magnitudes of the moments about the lower
limbs (Wheeler et al., 1985; Pai & Rogers, 1991), an advantage
for FES-assisted standing up, but will extend the duration of
the manoeuvre and therefore requiring more muscle activity. The
latter is only a disadvantage for FES-assisted standing up, if
several stand-sit manoeuvres need to be performed in a short
period of time. The initial body position can also be an
important factor (see section 2.1.1.5). Sitting down must also
be controlled. In particular the force with which the user
contacts the seat is important so as to avoid injury.
The discussion above has assumed that the techniques used to
achieve standing up and sitting would be the same as those
employed by able bodied subjects. However, it has long been
known that simply placing the hands on the knees can help those
with weak lower limb muscles (Gowers, 1879) (presumably by
providing an extending moment about the hip) and other techniques
have been adopted by those suffering from neuromuscular weakness
(Butler et al., 1991). These need to be considered further.
Doorenbosch and co-workers (1994) also demonstrated that the joint
moments are dependent to some extent on the technique employed
to stand up. It could be envisaged that a FES user could use
their upper arms to assist their standing up and sitting down,
but without a standing frame, by placing their hands on their
seat or its armrests during the initial or later periods of the
standing up and sitting down respectively, or by placing their
hands on their knees, to compensate for muscle weakness.
References:
Brindley GS, Polkey CE & Rushton DN (1978) Electrical splinting
of the knee in paraplegia. Paraplegia 16:428-435.
Butler PB, Nene AV & Major RE (1991) Biomechanics of transfer
from sitting to the standing postion in some neuromuscular
diseases. Physiotherapy 77(8):521-525.
Carroll SG, Triolo RJ, Chizeck HJ, Kobetic R & Marsolais EB
(1989) Teteanic responses of electrically stimulated paralyzed
muscle at varying interpulse intervals. IEEE Trans Biomed
Eng BME-36(7):644-653.
Doorenbosch CAM, Harlaar J, Roebroeck ME & Lankhorst GJ (1994)
Two strategies of transferring from sit-to-stand; activation of
monoarticular and biarticular muscles. J Biomech 27:1299-1307.
Gowers WR (1879) Pseudo-hypertrophic Muscular Paralysis: A
Clinical Lecture. J & A Churchill, London.
Kotake T, Dohi N, Kajiwara T, Sumi N, Koyama Y & Miura T (1993)
An analysis of sit-to-stand movements. Arch Phys Med Rehabil
74:1095-1099.
Marsolais EB & Kobetic R (1983) Functional walking in paralyzed
patients by means of electrical stimulation. Clinical
Orthopaedics & Related Research 175:30-6.
Pai YC & Rogers MW (1991) Speed variation and resultant joint
torques during sit-to-stand. Arch Phys Med Rehabil 72:881-885.
Rodosky MW, Andriacchi TP & Andersson GBJ (1989) The influence of
chair height on lower limb mechanics during rising. J Orthopaedic
Research 7(2):266-271.
Wheeler J, Woodward C, Ucovich RL, Perry J & Walker JM (1985)
Rising from a chair: Influence of age and chair design. Physical
Therapy 65(1): 22-26.
Michael J. Dolan, Lecturer in Biomedical Engineering,
Dept. Orthopaedic and Trauma Surgery, Fleming Building
University of Dundee, Dundee DD1 4HN, Scotland, U.K.
Tel: ++ 44 (0)1382 344642 Fax: ++ 44 (0)1382 344644
E-mail: m.j.dolan@dundee.ac.uk
www: http://www.dundee.ac.uk/orthopaedics/mjdolan
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