Abstract
FES systems in Europe and North America are generally used only as assistive devices. For the last 30 years
a number of rehabilitation methods utilizing basic FES principles were developed
in Russia. However, FES usage for rehabilitating patients with orthopaedic and neurological
pathology has its own important points, including the usage of specific
equipment and methods. By now our experience is based on the treatment of more
than 6000 patients with different motion abnormality. Therefore FES usage is effective for
patients with no pathology of central and peripheral nervous system as well.
1
A survey and practice
The general conclusion
concerning development of the FES in Europe and in the North America is that it stopped methodically many years ago
(sorry if this viewpoint is inconvenient). This is in spite of well
sophisticated hardware progression and new investigations of motion programs
for able-bodied and damaged central nervous system (CNS) [1, 2, 3]. At present the FES systems
are used mainly only as assistive devices or prosthesis of motion management
system CNS. Central Prosthesis Institute in Moscow, Russia, continued research into using FES as primary rehabilitation tool for the last 30 years. A number of
experimental works were dedicated to neurophysiological
aspects of influence of electrical impulses on human muscles [4]. These
investigations made it possible to suggest new methods of synchronizing
electrical stimulation impulse to muscle’s motion cycle. The effectiveness of
methods was examined experimentally and improved at the next stage according to
the achieved results. A number of different FES systems were developed by this time. The practical usage of FES in Russia is also different from that abroad. Instead of stimulating nerves, as
done abroad, Russian researchers prefer to stimulate body of muscles. The
second difference is the contingent of patients. These are not only patients
with hemiplegia or spastic spinal-cord-injured subjects, but also different
orthopedic and neurological patients with normal CNS or almost saved peripheral
nervous system. This practice includes lower extremity prosthetic patients, low
back pain and scoliosis patients, patients with consequences of poliomyelitis,
cerebral palsy, stroke, occlusive diseases of arteries of lower extremity. The FES method proved to be good for all kinds of above described pathologies
[4].
The neurophysiological and biomechanical investigations of the FES treatment results show the global effect of the FES therapy [5, 6]. One of the main results is reprogramming the muscle
automatic program in the walking cycle. This effect stays for a period from
half a year to a year or longer, depending on the decease. Other experimental
works helped to invent a new method of diagnosing the insufficient muscle
function.
The survey of current FES systems that are manufactured in the world is shown. There are many
different FES systems represented at the world
market. In spite of this it is hard to find any adoptable system for multichannel surface muscles stimulation while walking or
any another repeatable motion whole body or extremities which could be usable
in clinical practice. Only experimental systems exist in specific Labs or
clinics. Some of them use basic principles of FES, but not always correctly.
2
Criteria
Analyzing the history of FES systems development in the world and in Russia, and taking into consideration experimental
and practical results (including mistakes, inconveniences and other non-lack
outcomes of FES), it is possible to point out several main
criteria for building rehabilitation FES systems.
Such systems could follow these guidelines:
·
time
programming accuracy must not be less than 1/100 of walking or any another
motion cycle,
·
each
patient’s side should have its own synchronization device,
·
synchronization
should be achieved by using motion of different basical
joints (hip, knee, shoulder, elbow joints) or footswitches for heel and toe of
the foot,
·
synchronization
program should use different types of motion patterns and adequate settings for
each type of synchronization devices,
·
synchronization
program must follow definite patient’s motion pattern parameters,
·
wide ranges of
stimulation impulse amplitude, frequency, pulse width, time of beginning and
finishing the stimulation package along with high accuracy.
All principles written
above of using FES in clinical practice as a rehabilitation tool, are based on conclusions approved by our clinical
application.
At first, we need to
make a biomechanical investigation of the patient’s motion before prescribing FES rehabilitation. It has six main goals:
·
detailed
functional diagnostics of patient’s motion pathology and abnormal motion
patterns of the patient,
·
which
repeatable motion pattern needs to be used (walking, bicycling, etc),
·
determine,
which muscles should be stimulated,
·
which time
program needs to be used for each selected muscle,
·
what kind
of synchronization device is required to be applied for each patient’s side
(left and right),
·
what type of
synchronization algorithm will be adequate for the selected synchronization
device and given patient.
We can make several
conclusions at this point.
The first is that each
patient should have a biomechanical investigation before FES is used as a rehabilitation tool. Depending on the patient's problem a
locomotion for FES should be selected by using a biomechanical investigation,
that might include gait analysis or examination of any another cyclic motion at
lower or upper extremity. At this point the physician makes a decision
concerning the motion pattern for FES. For
example, if a patient shows a deep abnormal and nonrhythmic
pattern of walking the bicycling exercising could be used for FES. Another important question is what type of synchronization device is
necessary to use for a particular patient and what would be the criterion for
defining the motion cycle. For this aim it's better to use a biomechanical
transducer which shows the most stable process with good quality of motion
repetition. For example, if we have an unstable pattern of walking cycle for
the knee joint at the affected side and a stable pattern for hip joint at the
same side, we could use a goniometer for the hip
joint as a synchronization device.
The detailed motion
analysis with obligatory utilization of multichannel
surface EMG recording could help determining which muscles group needs to be
stimulated at the beginning of FES treatment
and the following stages. Often it's possible to find the general answer to
this question by a routine clinical examination. However, surface EMG
investigation should increase the accuracy of the decision.
Preliminary
biomechanical and EMG exploration are necessary for the most important
assessment – what should be the time program of FES? If the motion pattern is far from normal we could not use for the
first trials normal time program, because it is not to be synchronized with
abnormal pattern. For example, walking pattern of patients with cerebral palsy
or after stroke or after a long time of immobilization has a time shift of
muscle program from normal. Some patterns have very complicated time
disturbances for different muscles on each extremity.
At our experience [5,
6] the rehabilitation procedure of FES could take
from 20 minutes to one hour for a patient each day. The whole number of FES procedures is usually from 10 to 20. During FES it is necessary to have a complete information concerning work of
stimulation channels and synchronization transducers. Often when the patient
has a serious motion pathology it would be convenient for the physician to get
more biomechanical information from the patient. Therefore the best way to use FES for rehabilitation is to have on-line control of biomechanics data and
parameters of stimulation procedure. The most important stimulation parameters
are the beginning and the end of stimulation impulses relatively to the
patient’s motion cycle. On-line biomechanics data makes it possible to get
information about what kind of motion correction the patient has as a result of
FES. Consequently, the appropriate FES rehabilitation system should register necessary biomechanical data with
its own hardware devices.
3
Possible solution
According to the
criteria written above we have created a new 8-channel FES-rehabilitation
system called “STIMUL”. The system includes: the system unit which is placed on
a patient with a special belt; synchronization devices: goniometers
for hip and knee joints, footswitches (for heel and toe); a number of
differently sized electrodes, the system cable (with a length of 30 meters or
more), a computer with the WINDOWS operation system, specific software and
additional attachments. The cable connection was chosen basing on a long
experience, because a patient needs to have organized distinct and limited
walkway and biomechanical and stimulation parameters should be controlled the
whole time during FES. Our experiments show that any system with
connection between the patient and the physician’s computer by the radio
channel is limited. We found that it's possible to use this type of systems
only for patients with slight degree of motion disturbance.
In software a
physician could find different FES methodic
or create one with existing options and software instruments. During a FES procedure a physician could see at one-line regimen work of
synchronization devices and stimulation channels. It is also possible to change
the function condition of each device or stimulation channel options. When the
procedure is over the software could save all data and create a complete report
(biomechanical data are included).
The clinical
investigation of the system shows that the system is more convenient for
patients as well as physicians. Except that it is possible to
use it for different types of cyclic locomotion as for lower as for upper
extremity. A big number of synchronization devices and synchronization
algorithms makes it possible to adopt FES procedure for different types of patients including high degree
disability.
4 Discussion and Conclusions
The viewpoint written
above is based on a long experience of rehabilitating more than 6000 patients
with different types of motion abnormalities. The main aim of this paper is to
invite researchers and physicians outside Russia to use FES not only as
assistive devices, but also as a rehabilitation method for patients with motion
disabilities such as: cerebral palsy, stroke, poliomyelitis, after bones and
spinals column fractures, low back pain, endo and exso prosthesis for leg and upper extremity, occlusive
vascular deceases, and many others. At this time the general usage of FES systems in the world is usually limited to treating paralyzed patient
on the one hand and sport and fitness (i.e. able-bodied) persons on the other
hand. But it is almost anybody between them.
However, the most
important effect of rehabilitation FES is
reprogramming automatic muscle action, which is also useful when central
nervous and peripheral nervous system is not damaged.
Probably this is a good source for future
development of FES in rehabilitation industry.
References
[1]
Bobet J Can muscle
models improve FES-assisted walking after spinal cord injury? J. Electromyogr. Kinesiol. 8(2):125-32, 1998.
[2]
Sinkjaer
T, Haugland M, Inmann A, et all. Biopotentials as command and feedback signals in functional
electrical stimulation systems. Med Eng Phys.25(1):29-40,
2003.
[3]
Skelly MM, Chizeck HJ Real-time gait event detection for paraplegic FES walking. IEEE Trans Neural Syst Rehabil Eng. 9(1):59-68, 2001.
[4]
Vitenson AS, Mironov EM, Petrushanskaia KA, et all. Iskusstvennaia korrektsia
dvizhenii pri patologicheskoi hod’be. Moskva, OOO Zerkalo, 503 p. 1999.
[5]
Vitenson AS, Petrushanskaia KA, Skvortsov DV. Rukovodstvo po primeneniu metoda iskusstvennoi korrektsii hod’bi I ritmicheskih dvizhenii posredstvom programmiruemoi electrostimulatsii
mishts. Moskva, NMF “MBN”,
284 p., 2004.
[6]
Vitenson AS,
Petrushanskaia KA, Ot estestvennogo k iskusstvennomu upravleniu lokomociei. Moskva, NMF “MBN”,
439 p., 2003.
Acknowledgements
Special thanks to Dr. Vitenson
and Dr. Petrushanskaia for their consultations and
clinical approbation of the new FES rehabilitation system.