Trends in orthopedic biomechanics applied to rehabilitation

Abstracts

Conceitos de Biomecânica são constantemente utilizados nas mais diversas áreas. Tais conceitos são entretanto primordiais na área de Engenharia de Reabilitação. Este artigo pretende divulgar alguns estudos realizados e em andamento nas áreas de biomecânica e bioengenharia com o intuito de desenvolver novas técnicas para reabilitação de pacientes com algum tipo de deficiência motora. Estas deficiências podem ser de âmbito neurológico ou músculo-esquelético. Dentre as deficiências causadas por problemas neurológicos, pode-se mencionar os casos oriundos de lesões medulares, como a paraplégica e a tetraplegia, e os causados por lesões crânio-encefálicas. No campo das deficiências músculo-esqueléticas incluem-se amputações de membros inferiores ou superiores, doenças congênitas, e algumas doenças degenerativas, como a osteoporose.

Biomecânica Ortopédica; Estimulação Elétrica Neuromuscular; Próteses para membros superiores; Propriocepção Artificial; Modelo Biomecânico da Coluna Vertebral

ARTIGO DE REVISÃO

Trends in orthopedic biomechanics applied to rehabilitation

Rodrigo Lício Ortolan^I; Fransérgio Leite da Cunha^II; Daniela Cristina Leite de Carvalho^III; Juracy Emanual Magalhães Franca^IV; Adriana Simone Lopes Santa Maria^V; Orivaldo Lopes Silva^VI; Alberto Cliquet Jr^VII

^IElectrician Engineer - Post graduate studente at Master level in Electrical Engineering wiht focus in Biomedical Engineering (EESC-USP/SEL)

^IIMaster in Electric Engineering - Post graduate student at Doctorate level in Electrical Engineering with focus in Biomedical Engineering (EESC-USP/SEL)

^IIIPhysiotherapist - Post graduate student at Master level of Bioengineering Interunits (EESC/FMRP/IQSC-USP)

^IVElectrician Engineer - Post graduate student at Master level with focus in Biomedical Engineering (EESC-USP/SEL)

^VPhysical Educator - Post graduate student at Master level of Bioengineering Interunits (EESC/FMRP/IQSC-USP)

^VIFree docent EESC-USP

^VIITitular Professor EESC-USP/ FCM -UNICAMP

SUMMARY

Biomechanic concepts are constantly used in several areas. These concepts are however of a paramount importance in Rehabilitation Engineering. This paper aims to divulge some studies, both performed and ongoing in the areas of biomechanics and bioengineering with the objective of developing new techniques for rehabilitation of patients with motor problems. These problems can be of a neurologic or musculoskeletal nature. Among these disturbs caused by neurologic problems, we can mention spine cord injuries related ones, as paraplegia and tetraplegia, and those caused by cranioencephalic injuries. Musculoskeletal conditions include lower and upper limb amputations, congenital diseases and some degenerative diseases as osteoporosis.

KeyWords: Orthopedic Biomechanics, Neuromuscular Electrical Stimulation, Prosthetic Devices, Artificial Proprioception, Rehabilitation Engineering.

SECTION I

INTRODUCTION: MOBILITY PROBLEMS

One of the major problems faced by modern society is integration of people with any kind of deficiencies for daily activities. Frequently it is not noticed in most of people any difficulty in performing simple tasks as opening a door, hearing and answering a telephone call, stand up, walking or even drink a cup of coffee. Several efforts to rehabilitate those individuals are being done in many places of the world. There are good results in areas such as ergonomics, building, disabled people considering architectural projects, however development of devices and technology specific for each case is essential. Patients who suffered spine cord injuries, according to lesion level, should be able to walk and move, as well as amputee patients could have their limbs rehabilitated by the use of functional prosthesis and in some cases as similar as possible to the natural limb. New methods for healing degenerative diseases caused by acquired motor deficiencies should be investigated and new alternatives for sensorial rehabilitation should be found for visually impaired patients.

So, to allow a motor impaired patient to become more independent, productive and this way more integrated to the society, this paper aims to display some of current trends in the filed of biomechanics and bioengineering, applied to rehabilitation of patients with some motor impairment. These deficiencies may be of neurologic or musculoskeletal. Among those caused by neurologic problems, we could mention those from medullary injury, as paraplegia and tetraplegia, and those caused by cranioencephalic problems. One of the consequences of this kind of problems is lack of proprioception. Among those of musculoskeletal origin, we can find lower and upper limb amputations, congenital diseases and some degenerative diseases such as osteoporosis. This classification is displayed in Figure 1.

Several advances in this field can allow patients with a certain types of spine cord injury hope of recovering some movements or even to walk. High technology prosthesis, which use myoelectrical signs for its control allow the performance of variable tasks, and are widely sold around the world, however there is still much to be done to make them fully anthropomorphic.

SECTION II

NEUROLOGIC PROBLEMS

Individuals with neurologic conditions suffer from different degrees of sensorial and motor deficiency causing huge psychological impacts. Attempting to reintegrate those individuals to the society, multi-disciplinary groups are formed, aiming to elaborate strategies that are adequate in rehabilitating those people.

Among the works related to neurologic conditions developed in Rehabilitation Engineering we will mention those related to neuromuscular electrical stimulation, electric-tactile stimulation and communication environment for those cranioencephalic injured individuals.

Neuromuscular Electric Stimulation

Skeletal muscle stimulation has been shown as useful for improving movement of paralyzed limbs. This way, Neuromuscular Electrical Stimulation (NMES) came to be used aiming muscle re-education, atrophy prevention, temporary control of spasticity and contratctures and swelling. ⁽⁵⁶⁾.

The electrical sign applied through surface electrodes induces lines of field inside the limb, making Na ions located externally to motor nerve membrane to suddenly influx to the nerve, generating an action potential. This disturbance proceeds through axon to the synaptic cleft and the muscle then contracts. ⁽⁴²⁾.

One of the first historic reports of NMES was around 1750, when an hemiplegic violinist, due to a cerebral stroke had his upper muscles paralyzed and was electrically stimulated with an static source, and after two years under this treatment came back to play his violin. ⁽⁴⁷⁾. In 1985, in Glasgow, Scotland, a pioneer work was developed which lead to the first walk in laboratory of a completely paraplegic patient, using NMES in the inactive limbs. Thus, besides being useful in physioterapical treatment, NMES can be adopted to restore walking in spine cord injuried patients. ⁽²¹⁾

NMES is performed through rectangular pulses of low frequency and high amplitude, giving efficacious stream of some milliamperes. Signal frequency is adopted in a way that offers a satisfactory muscle contraction, versus time to reach muscle fatigue. The equipment is a source of controllable tension, for in cases of stream sources, in case the electrode is not well fixed to the skin there is the possible inconvenience of reaching high stream intensity with risk of causing burnings aggravated by the fact of lack of sensation of the spine cord injuried. Besides this, these systems are designed to work with batteries, avoiding the risk of discharge form the network ⁽²⁰⁾.

For walking it is necessary a number of movements which perform trunk extension (paravertebral muscle), hip extension and abduction (gluteus maximus and medium), knee extension (quadriceps), knee flexion and hip extension (ischiotibials), plantar flexion of ankle and knee (gastrocnemius) and withdrawn reflex (fibular nerve) - Figure 2. So, 16 channels (8 each leg) are enough to restore walking in spine cord injuried patients at a high level (cervical) ⁽⁵⁴⁾.

Complete paraplegic when walking through NMES consume about 400% more oxygen during walking when compared to baseline, and have an energy consume of 349 J/kg.m. While march performed by those individuals through mechanical orthesis, so making an hybrid system, consume significantly less energy when compared to system using only NMES. According to the orthesis the energy consumption can reach 90 J/kg.m ^{(2, 22)}. The reaction to floor forces of the leg in the hybrid system is considerably smaller than in the system using only NMES ^(24,25).

A patient with spine cord injury has a physiologic atrophy due to changes in metabolic and contractile properties of muscle fibers leading to a reduced working capacity of the muscle. So, patients get fatigued earlier, taking from 24 to 48 h to muscle submitted to NMES return to normal. Tests were performed in patients by using one stimulation channel, recruiting all quadricipital group, and multi-channel sequential stimulation, recruiting in a multi-plexate way the following muscles: lateral vastus, medial vastus, femoral rectus, which are part of the quadriceps. It was noticed that paralyzed muscle resistance to fatigue could be increased by an exercise program induced by NMES. Besides this, with a multi-channel stimulation the muscle prolongs the time to get into fatigue, since this process is similar to the physiological stimulation ⁽⁵⁰⁾. However, with the use of multi-plexate technique, the muscle doesn’t develop enough strength to perform walking.

For gait control using multi-channel stimulators, several works were performed, proposing to control through neural networks, allowing walk to be as similar as possible to the natural one. The network is composed of 3 layers and can use as points of entrance the angles joints of knee, ankle and hip ^{(59, 60)}; additional to these, it can also be used as an entrance for the network the floor vertical reaction force and the momentum anterior/posterior linked to the upper limbs in gauntlets of crutches/walkers ^{(57, 58)}. As angle sensors for joints are used electro-goniometers in patient’s knee, hip and ankle, and for measuring vertical component of floor reaction force and anterior/posterior momentum, special inner soles (FSRs placed in determined points of foot soles) or even special crutches (with strain gauges placed to measure crutch deformation) ⁽⁵³⁾. For walking performance the network should have exits that are proportional to changes in NMES pulse width in femoral and fibular nerves at individual’s leg ^{(54, 59, 60)}, so contracting the femoral rectus, anterior tibial ischio-tibial, gluteus maximus and gastrocnemius muscles ^{(57, 58)}.

The neural network compares the step taken to normal gait and when relation between them is good, an improvement supervised feed back program is applied. Network training is performed off line and later on line. Movement control is made in such way that muscles are contracted only when necessary and this information in gathered by sensor monitoring. With this control we can have a larger time before muscle gets fatigued.

However, for using NMES out of a lab, the system should be able to match the different necessary conditions, such as overcoming small obstacles ⁽⁵³⁾, or to climb stairs. A command was including proposed, as a voluntary control of movement through acknowledgment of voice patterns, using neural networks ^{(19, 57, 58)} and also through acknowledgment of myoelectrical sign (EMG) of muscle preserved above the lesion, using digital analysis ⁽⁵²⁾.

NMES can also be used in rehabilitation of tetraplegic patients, restoring upper limb movements and functions. Electrodes Surface electrodes were used to recruit muscle units and to perform the desired grip function - Figure 3. The proposed claw functions are Palmar Prehension, Composed Claw and a composition of the Strength Grip Claw and indicator finger extension ⁽²⁸⁾. The composition of strength claw and index extension can be use for typing a computer’s keyboard, and the composed claw is used for lateral prehension through thumb opponens muscle, allowing, for example, holding a credit card ⁽¹⁴⁾.

For hand muscles control it was developed a voice system by the use of artificial neural networks. The network is responsible for acknowledging voice patterns, identifying the phonemes /a /, /e /, and /i /, associating each phoneme to a claw type. The system presents an index of success of 70% for masculine voices and 20% for feminine voices, due to the fact of the net was trained exclusively for masculine voice ⁽²³⁾.

Tetraplegic patients have no sensation in their limbs, and their hand can exert an excessive force in stimulated prehension of objects, and damage can occur to objects as with a disposable glass. To solve this problem a special device composed by a glove of Lycra with stress gauges based in FSRs placed in the corresponding areas of the distal phalanges of the thumb, indicator and medium. The FSRs sign was filtered, digitized and visualized graphically through a software in language C, for prehension of objects with different weights ^{(12, 13, 15)}. From the study of these signs it is so possible to implement a feed back system, making the system really adequate in two different ways: first, is that after processing the sign a control software determines the intensity of stimulation according to the desired levels, and second, through a electron-tactile proprioception process, where the individual him/herself can know how to correct the power his/her hand is applying to a given object.

Electron-tactile Stimulation

When an individual looses one or more of his/her primary sensations (vision, hearing, proprioception, and tact), which can be consequence of neurological or musculoskeletal problems, electrical stimulation can also be used for sensorial feed back ⁽⁴⁸⁾.

In this case, it is worthy to consider that a median individual has about 2 m² of skin ⁽³⁵⁾, and in the consequent advantage of the exploration of the tactile sensation as an alternative sensorial entrance channel for transmitting the lost information. Besides the availability of a large area for information transmission, several other advantages of the use of tactile sensation can be considered such as releasing the remaining senses for other tasks, being not normally disturbed by rapid and constant environmental stimuli, allowing large amounts of information which are compacted within the band of useful space-temporal response and tactile stimulation may be performed by using light and small panels placed under the clothes avoiding cosmetic problems and rejection by the user due to social pre-concepts ^{(46, 55, 62)}.

Safe and comfortable tactile sensations can be generated through application of well controlled electrical stimuli over skin surface. This procedure is called electron-tactile stimulation. Studies demonstrated that its utilization could be optimized (by number of electrodes reductions, for example) when the system is developed to generate a Phi tactile phenomenon ⁽⁴⁹⁾. This phenomenon allows the creation of a series of moving figures (of different sizes and positions) over the skin using only 2 or 3 electrical stimulation channels. This properties particularly important because spatial modulation presents the best results ⁽⁴³⁾.

The Phi tactile phenomenon occurs when two stimuli are simultaneously applied to adjacent places over the skin, generating a unique sensation in a region between them. This sensation is determined by the distance between the electrodes, the amplitudes and temporal orders of the signs, and corresponds to an image composed by their combination. For this, it is normally called phantom sensation ^{(7, 35)}.

Electron-tactile sensation has been used for compensate lost of vision ^{(3, 34)}, hearing ^{(61, 63)}, and proprioception ^{(11, 49)}. This last, particularly is fundamental for the development of more efficient prosthesis since proprioception indicates the position and orientation of the limbs, and the degree of muscle contraction. And the proprioceptors are present mainly in muscles, joints and tendons. For instance, in the development of prosthesis for lower limbs using NMES for spine cord injuried patients as described in the section before, Castro and Cliquet ⁽¹⁶⁾ used a special inner sole with FSRs, and electron-tactile stimulation of the shoulder of the patient, making possible to him to know when his foot is in contact with the floor in the walking process.

Communication Environment for Head Injuried Patients

In many cases patients of head injury have loss of mobility and sensation in all the body, and absence of communication with their outside environment, remaining active only the ocular sensation. Aiming to promote a link of communication between those people and the outside world, artificial communication environments were developed.

The system is composed by a LED (Light Emitter Diode) matrix and a menu of varied needs to be communicated. The LEDs run the menu, staying for a time over each need. The choice is made by blinking the eyes during 2 seconds or more when the LED is over the desired item, triggering a sound device to call the attention of a person who is around. The blinking sensor is composed by an infrared emitter, which incides light over eyelashes and eyelids, and an infrared sensor. When the patient has eyes opened, eyelashes serve as light fence reflecting it back to the sensor. This system has still the capability of allowing the patient to communicating by answering direct questions through a "yes" and "no" code ⁽¹⁸⁾.

An other version, able to track eye movement and blinking, and making possible to the patient roll over a screen is under development. This would make possible to choose the desired option in a process similar to the use of a mouse in a computer screen. As in the other system, the patient should close the eyes for at least 2 seconds to choose the option, triggering a sound device.

Eyes movement is performed by 3 pairs of extra-ocular muscles placed around the eye globe, such that one pair is responsible for the horizontal movement, other for the vertical, and a third pair for the oblique movement of the eye globe ⁽³⁸⁾. Through Electron Myographic techniques it is possible to measure the potential of extra-ocular muscles according to the position of the eyes, by the use of surface electrodes.

To capture the signs of eye movements 5 electrodes are placed: one pair at the sides to capture horizontal movements, one pair above and below the eye to capture the vertical movement, and an other electrode is used as a reference ⁽⁶⁾. With this system, the patient does not depend on the LEDs movement on the panel, since can run over the screen at will. The system can be on 24 hours with the sensors connected, and, when the individual wants close the eyes, can choose a rest mode. And also the patient can choose letters and write some phrase.

SECTION III

MUSCULO-SKELETAL CONDITIONS

In this section some of the trends in orthopedic biomechanics, superior limb prosthesis and osteoporosis are discussed. Osteoporosis is a problem that can be originated in spine cord injuried patients due to the lack of movements. Some of the subjects discussed in the above section, as artificial proprioception, for example, can also be applied in musculoskeletal conditions. In this example it is possible to apply the knowledge to produce an upper limb prosthesis with artificial temperature sensors, using the same concepts as discussed in artificial proprioception.

Study of Spine Stress Factors

One of the major problems to be considered in biomechanics is what happens in spine. The inadequate lifting of a load brings several injuries, affecting a large percent of population. The index of incapacity and morbidity due to low back pain is very high, and causes huge prejudices and very severe social and economic problems. In the USA, in 1990 192 million dollars were expent with medicines for low back pain, and the total cost of the treatments was estimated in more than 50 billion-dollars/year ⁽⁴⁰⁾.

With the objective of reverting this picture several authors described some biomechanical models of the spine, where contact forces were analyzed when a load was lifted in an improper way ^{(1, 17)}, which can reach some times the individual’s weight himself, according to the lifted load ⁽²⁹⁾. The analysis of these forces, previously proposed by some authors ^{(11, 29)}, considers the column as a rigid pole, so representing a very poor approximation to this system, once several involved muscular forces are not adequately analyzed, and the rectification movement of the spine not took into consideration ⁽¹¹⁾.

One of the ways to deal with this problem is to elaborate a model closer to the real conditions. For a more accurate model, several mechanic and anatomic aspects should be considered, as well as an adequate mathematical model. Accordingly a new model is under development with a more precise calculation of the actual forces acting in the spine, allowing a better interpretation of the stresses, avoiding traumas, postural problems and so, giving subsides to correcting usual weigh bearing problems.

Myoelectrical Prosthesis for Upper Limbs

Rehabilitation of upper limb amputees or malformation bearing patients, through intelligent prosthesis is another theme under study. Prosthesis used in recovery of this kind of patients can be understood as manipulator robots ⁽²⁸⁾. Unfortunately, in case of rehabilitation, the problem of control is more sophisticated, since generally artificial controllers or hybrid systems should replace control systems of the human body ⁽²⁸⁾.

The difference between a robot and an intelligent prosthesis is that the man/machine interface should be better analyzed in this last case by the control system. There is still the need to replace the natural sensors that were lost, and of the command execution mechanisms, which can also be artificial. Many times, it becomes impossible to recover the natural control, and it is necessary to develop alternative methods by applying new kinds of sensor ⁽³⁰⁾ and actors ⁽³¹⁾ to replace the lost ones. In the research of this kind of problems there is an integration of areas such as Medicine, Mechanics and Electrical Engineering.

One of the aspects that can not be ignored in developing upper limb prosthesis is the psychological side ⁽³⁶⁾. The experience shows that a purely esthetic prosthesis ⁽⁸⁾ is preferred t a functional one if this brings constraint to the patient. So, prosthesis should be very much anthropomorphic (Figure 4), imitating a human hand ^{(26, 27)}, both in an esthetic aspect as in movements. Most of the current prosthesis for upper limb have very restrict movements, as well as a control system that demands a long training time, making the rejection index to be high ^{(9, 36)}.

So, the main objective is to reduce the rejection index of upper limb prosthesis, making easier their control training process, and making them more anthropomorphic. A new approach that can also be interesting for this area is to give a prosthesis with synchronic movements to the other hand, in cases of unilateral amputation ⁽⁴⁴⁾. This is also a severe problem when projecting prosthesis for the upper limb, since their control is not made in a natural way. The difficult synchronization of the prosthesis with the existing hand is also an important factor for rejection. This can de made by using knowledge from previous works ⁽²⁸⁾, with grasping of objects that are larger of the size of the hand, and defining several kinds o co-ordinated movements possible for such a grasping. Conversely, traditional prosthesis, which need a long training time to learn how to use it, this proposed prosthesis will be adapted according to the patient making the control simplified and leaving to the controlling plate the several possible configurations.

For this, a new study of these synchronic movements should be performed, relating these functions with other pattern objects of larger dimensions. This will lead to a significant control strategy change, starting from controlling signs, preferably through myoelectrical signs, to prehension functions.

Ultrasound in the Treatment of Osteoporosis

Osteoporosis is a metabolic disease promoting bone mass reduction, micro-architecture changes, making the bone fragile and consequently leading to an increased risk of fracture.

Osteoporosis can be associated to aging, menopause and systemic diseases promoting bone mineral reduction, as rachi-medullary traumas. However, its incidence is mainly related to deficiency of ovarian hormone in post-menopausal women, affecting 1/3 of those ⁽⁴¹⁾. Ovarian hormone deficiency disturbs the balance between osteoblasts and osteoclasts, responsible cells for the formation and house keeping of bone tissue. With the reduction of serum levels of estrogen, it is believed that osteoclasts become hyperactive, penetrating deeply lamellar plates and perforating them ⁽³²⁾. These changes increase bone fragility and reduce bone ability to resist to compression and twisting, making it more vulnerable, and increasing incidence of fractures.

According to world statistics, the most frequent osteoporotic fractures are of spine (17%), proximal femur (16%) and distal radius (11%), where a larger concentration of lamellar bone is found, and, except radius, are directly weight bearing bones ^{(10, 37, 51)}. Femoral neck fractures may lead sequelae including loosening of independence to death. It is estimated that up to 2000 about 15 million of Brazilian people will present with a risk of developing osteoporosis ⁽³⁹⁾, increasing in 2025 to 34 million of people aged above 60 years old ⁽⁴⁵⁾.

Bone and conjunctive tissue, when deformed, generate local electrical potentials, which are called SGP (stress generated potentials) which contribute to bone repair ⁽⁵⁾ for working as stimulators for bone forming cells. In this way, the use of pulsatile ultrasound promotes micro-deformations in the bones, which are subject to mechanical energy, crates SGPs and stimulates bone formation. So, cells act as biological transductors with a larger mitotic activity produced by electrical stimulation ⁽⁴⁾.

Due to the severity of the clinical picture, several treatments are available aiming to prevent or to ameliorate this picture, which are based on medicines, nutritional orientation and physical exercise ⁽³³⁾. However, there are no studies that evaluate the efficiency of low intensity ultrasound in already installed cases of osteoporosis. So, an experimental work is being developed in an animal model subject to ovarectomy aiming to evaluate the response to treatment. It is expected from bone tissue to react by maintaining or increasing the bone mass amount in an specific region, reducing fractures and sequelae.

SECTION IV

CONCLUSIONS

Biomechanic concepts applied to rehabilitation allow development of systems, artificial organs and orthopedic devices which are intelligent prosthesis which are esthetic and functional, effectively contributing to improve life quality of physically impaired patients. The researches presented in this paper show to be viable mainly if those concepts are well employed demonstrating that biomechanics can reach unexpected fields. So, study and development of new techniques and measuring and working equipment, and the dissemination of centers focused in biomechanics are of great value for the development of projects in the field of rehabilitation.

ACKNOWLEDGEMENTS

The authors would like to thank FAPESP, CAPES and CNPq for funding the researches presented in this paper.

REFERÊNCIAS

These works were performed at Escola de Engenharia de São Carlos - Universidade de São Paulo (EESC/USP), at Departament of Electrical Engineering by Bio-cybernetic Lab and Rehabilitation Engineering (LABCIBER)^1,2,4,7, in the Post-graduate course Bioengineering Interunits^3,5,6,7 and at Department of Orthopedics and Traumatology of Faculdade de Ciências Médicas- UNICAMP⁷.

Escola de Engenharia de São Carlos - Universidade de São Paulo

Departamento de Engenharia Elétrica - Laboratório de Biocibernética e Engenharia de Reabilitação - Caixa Postal 359 - 13560-250 - São Carlos - SP

• 1. ANDERSSON, G.B.J et al. Quantitative studies of back loads in luting. SPINE, v.1, p-178-185, 1976.
• 2. ANDREWS, B.; CLIQUET JR., A.; OLIN, M.; BURNHAM, R.; TRASHER, A. Paraplegic locomotion: a linked knee-ankle-foot hybrid system. IN: 2^nd Annual IFESS Conference and Neural Prosthesis: Motor Systems 5. Burnaby, Canada, pp. 165-167, 1997.
• 3. ANTONINO, P.H., CLIQUET JR., A. Sistema de estimulação táctil para recepção de informações ópticas. Anais do I Fórum Nacional de Ciência e Tecnologia em Saúde, Caxambu, MG, Brasil, 20-24/11/92, p. 196-198, 1992.
• 4. BASSET, C.A.L. Biologic significance of piezoeletricit: Calcify Tissue Res, 1:252-172, 1968.
• 5. BASSET, C.A.L. e BECKER, R.O.: Generation of Electric Potentials by Bone in Response to Mechanical stress. Science (137): 1063-4, 1962.
• 6. BASSI, T. A. G.; CLIQUET JR., A. Relatório de Iniciação Cientifica - FAPESP, Departamento de Engenharia Elétrica, UNICAMP, Campinas, S.P., 1997
• 7. BÉKÉSI, G. Sensory Inhibition. Princeton Press, USA, 1967.
• 8. BLOHMKE, Fritz. Compêndio Otto Bock: Próteses para o membro Superior. Berlin: Schiele & Schön, 1994.
• 9. BOCCOLINI, F. Reabilitação: Amputado - Amputações - Próteses. São Paulo: Robe Livraria e Editora, 1990.
• 10. BONNICK, S.L. The osteoporosis handbook: Every womans guide to prevention and treatment. Taylor Publishing Company, 1994.
• 11. CARLSÖÖ, S. The static muscle load in different work positions: an electromyographic study, Ergonomics, v.4, p.193, 1961.
• 12. CASTRO, M. C. F.; CLIQUET JR., A. A low cost instrumented glove for monitoring forces during object manipulation. IEEE Transactions on Rehabilitation Engineering. ISSN: 1063-6528. The Institute of Electrical and Electronics Engineering, EUA, v. 5, n. 2, pp.140-147, 1997.
• 13. CASTRO, M. C. F.; CLIQUET JR., A. An artificial grasping evaluation system for the paralysed hand. Medical & Biological Engineering & Computing. Journal of the International Federation for Medical & Biological Engineering, GB, v. 38, n. 5, pp. 1-6, 2000.
• 14. CASTRO, M. C. F.; CLIQUET JR., A. An artificial grasping system for the paralysed hand. Artificial Organs. ISSN: 0160-564-X. Journal of the International Society for Artificial Organs. Blackwell Scientific Publications, Inc., MA, EUA, v.24, n. 3, pp.1- 4, 2000.
• 15. CASTRO, M. C. F.; CLIQUET JR., A. Uma luva instrumentalizada para tetraplégicos. Revista bresileira de Engenharia, Caderno de Engenharia Biomédica. ISSN: 0102-2644. Sociedade Brasileira de Engenharia Biomédica, Rio de Janeiro, v. 12, n.1, p.41-56, 1996
• 16. CASTRO, M.C.F.; CLIQUET JR., A. Artificial sensorymotor integration in spinal cord injured subjects through neuromuscular and electrotactile stimulation. Artificial Organs. ISSN: 0160-564-X. Journal of the International Society for Artificial Organs. Blackwell Scientific Publications, Inc., Cambridge, MA, EUA, v.24, n. 9, 2000.
• 17. CHAFFIN, D.B. Biomechanical modeling of the low back during load lifting, Ergonomics, v.31, n. 5, p. 685 - 697, 1988.
• 18. CLIQUET JR., A. Bioengenharia já consegue milagres; Milagres viram referência dentro da Bioengenharia; Equipamentos entram na batalha pela vida. Jornal A Tribuna de Campinas. Campinas, São Paulo, Brasil, capa, pag. 6, 23/11/1997
• 19. CLIQUET JR., A. et al. A neural network-voice controlled neuromuscular electrical stimulation system for tetraplegics. Rehabilitation Engineering Society of North America-RESNA. ISBN: 0-932101-30-5/ISBN: 0883-4741. RESNA press, Washington DC, EUA, 12, pp. 29-31, 1992
• 20. CLIQUET JR., A. Paraplegic gait restoration through neuromuscular electrical stimulation based strategies. Medical & Biological Engineering & Computing, 29 (Supplement), p.711, 1991.
• 21. CLIQUET JR., A. Paraplegic locomotion with neuromuscular electrical stimulation based systems - a feasibility study". Ph.D. thesis, University of Stratchclyde, Glasgow, UK, 1998.
• 22. CLIQUET JR., A.; BAXENDALE, R. H.; ANDREWS, B. J. Paraplegic Locomotion and its metabolic energy expenditure. In: Comprehensive Neurologic Rehabilitation - Vol. 3 - Neuromuscular Stimulation: Basic Concepts and Clinical Implications (Capítulo 11). Ed. Rose, Jones and Vrborá. ISBN: 0-939957-17-5. Demos, New york, EUA, pp. 139-146, 1989.
• 23. CLIQUET JR., A.; MENDELECK, A.; QUESNEL, D. R. F.; SOVI, F. X.; FELIPE JR., P.; OBERG, T. D.; LEMOS, G. J. P., GUIMARÃES, E. A.; QUEVEDO, A. A. F. A neural network-voice controlled neuromusculsr electrical stimulation system for tetraplegics. Rehabilitation Engineering Society of North America-RESNA. ISBN: 0-932101-30-5 / ISSN: 0893-4741. RESNA Press, Washington DC, EUA, 12, pp. 29-31, 1992.
• 24. CLIQUET JR., A.; SOLOMONIDIS, S. E.; ANDREWS, B. J. Paraplegic locomotion with neuromuscular electrical stimulation. In: North Sea Conference on Biomedical Engineering. International Federation for Medical and Biological Engineering, Antwerp, Bélgica, 1990.
• 25. CLIQUET JR., A.; SOLOMONIDIS, S. E.; ANDREWS, B. J.; PAUL, J. P. Fns in standing up paralysed person - a biomechanical assessment. Clinical Applications of Biomechanics. Biological Engineering Society, University of Salford, GB, 1988.
• 26. CUNHA, F. L. da et al. Determinação dos Valores dos Ângulos entre as Juntas de um Dedo Através do Processamento Digital de Imagens. In: II Simpósio Interdisciplinar em Tecnologia e Saúde, Anais... p. 18, Rio de Janeiro, 1998.
• 27. CUNHA, F. L. da, SCHNEEBELI H. A., DYNNIKOV V. I. Obtenção das Ligações Cinemáticas entre os Dedos de uma Prótese Adaptativa para Mão Humana. In: XVI Congreso Nacional de Control Automático, Anais... Vol. 2, p. 520 - 524, Buenos Aires, 1998.
• 28. CUNHA, F. L., SCHNEEBELI, H. A., DYNNIKOV, V. I. A development of Anthropomorphic Upper Limb Prostheses with Human-Like Interphalangian and Interdital Couplings. Artificial Organs - Março de 2000, Vol. 24, No. 3, pp. 193-197..
• 29. DANIELS, M.L.A., WORTHINGHAM, C. Provas de função muscular, Interamericana, 1981.
• 30. DE CASTRO, M. C. F. Uma Luva Instrumentalizada para Tetraplégicos. 1996. Dissertação (Mestrado em Engenharia Biomédica) - DEB/FEE/UNICAMP.
• 31. DE VINCENZO, C. V. et al. Modelagem mais Precisa dos Movimentos Mecânicos do Oscilador Piezelétrico. In: XVI Congresso Nacional de Controle Automático, Anais.Vol. 2, p. 449 - 454, Buenos Aires, 1998.
• 32. DEMPSTER, D.A.; LINDSAY, R.. Pathogenesis of osteoporosis. The Lancet. 341: 797- 801, 1993.
• 33. DRIUSSO, P. Efeitos de um programa de atividade física na qualidade de vida em mulheres com osteoporose. Dissertação de Mestrado, Programa de Pós-Graduação Fisioterapia, Universidade Federal de São Carlos, 2000.
• 34. FONSECA, D.V.; ARAÚJO, M.V.; MALENA, G.P.G.; BARANAUSKAS, V.; CLIQUET JR., A. Studies in a tactile vision substitution systems. Physics in Medicine and Biology, v. 39a, n. 2, p. 865, 1994.
• 35. GIBSON, R. H. Electrical stimulation of pain and touch. In: The Skin Senses. Ed.: D.R. Kenshalo, Springfield, Illinois: Charles C. Thomas, p. 223-260, 1968.
• 36. GIRAUDET G. Iniciação à Aparelhagem dos Deficientes Físicos. São Paulo: Organização Andrei Editora, 1978.
• 37. GROSSI, R.; CAMPELLO, E.C.; OLIVEIRA, N.A.L.; GROSSI, C.V. Fraturas osteoporóticas: Clínica e tratamento ortopédico. ARS CVRANDI Clínica Médica, vol. 29, junho, 1996
• 38. GUYTON, A. C. Fisiologia Humana. Rio de Janeiro, editora Ganabara Koogans S. A., 1988.
• ³⁹
  IBGE(on line), Disponível: http://www.ibge.gov.br(capturado 20 fev. 2000).
• 40. INDEX OF /DISSERTA96/MERINO,(on line), Florianópolis, fev. 1996. Disponível: http://www.eps.ufsc.br/disserta96/merino/(capturado 5 abr. 2000)
• 41. JOHNELL, O. Advances in osteoporosis: better identification of risk factors can reduce morbidity and mortality. J. Int. med., 239: 299-304, 1996.
• 42. KOVÁCS, Z. L. O cérebro e sua mente: uma introdução a neurociência computacional. São Paulo, edição acadêmica, 1997.
• 43. KUME Y. and OHZU H. Electrocutaneous stimulation for information transmission - I: optimum waveform eliciting stable sensation without discomfort. Acupuncture and Electro-Therapeutics Research, Int. J., v. 5, p. 57-81, 1980.
• 44. LATWESEN, A., PATTERSON, P.E. Identification of Lower Arm Motions Using the EMG Signals of Shoulder Muscles. Med. Eng. Phys., Vol. 16, p. 113-121, March 1994.
• 45. LEDERMAN, R.; CARNEIRO, R.A. Osteoporose: saúde pública no Brasil. ARS CVRANDI Clínica Médica, v. 29, p. 17-24, jun, 1996.
• 46. MASON, J.L., MACKAY, N.A.M. Pain sensations associated with electrocutaneous stimulation. IEEE Transactions on Biomedical Engineering, v. 23, p. 405-409, 1976.
• 47. MCNEAL, D. R. 2000 years of electrical stimulation. In: Functional Electrical Stimulation: Applications in Neural Prostheses, edited by F. T. Hambrecht and J. B. Reswick. New York: Marcel Dekker, 1977, pp 3-35.
• 48. NOHAMA, P., CLIQUET Jr., A. Sensação Fantasma: Avanços da Estimulação Eletrotáctil no Estudo de Propriocepção Artificial, RBE - Caderno de Engenharia Biomédica, v. 14, n. 2, p. 7-35, jul/dez 1998.
• 49. NOHAMA, P., LOPES, A.M.V.A., CLIQUET JR., A. Electrotactile stimulator for artificial proprioception. Artificial Organs. V. 19, n. 3, p. 225-30, 1995.
• 50. PEIXOTO, B. O.; CLIQUET JR., A. Redução da fadiga muscular através da Estimulação Elétrica Neuromuscular em pacientes portadores de lesão medular. Revista de Bioengenharia, Caderno de Engenharia Biomédica. ISSN: 0102-2644. Sociedade Brasileira de Engenharia Biomédica, Rio de Janeiro, v.12, n.2, pag. 21-46, jul/dez 1996.
• 51. PLAPLER, P.G. Osteoporose e Exercícios. Rev. Hosp. Clin. Fac. Med., SP, 52 (3): 163- 170, 1997.
• 52. QUEVEDO, A. A. F.; CLIQUET JR., A. A system for digital analysis of eletromyographic signals. In: Myoelectric Control Symposium93 (Future Trends in myoelectric technology). ISBN: 1-55131-004-X. Institute of Biomedial Engineering, University of New Brunswick, Fredericton, Canada, pp. 128-132, 1993.
• 53. QUEVEDO, A. A. F.; PATLA, A. E.; CLIQUET JR., A. Methodology for definition of neuromuscular electrical stimulation sequences: application on overcoming small obstacles. IEEE Transactions on Rehabilitation Engineering. ISSN: 1063-6528. The Institute of Electrical and Engineers, EUA, 5(1), pp. 30-39, 1997
• 54. QUEVEDO, A. A. F.; SEPÚLVEDA, F.; CASTRO M. C. F.; SOVI, F. X.; NOHANA, P.; CLIQUET JR., A. Development of control strategies for restoring function to paralyzed upper and lower limbs. In: IEEE Annual Meeting Engineering in Medicine and Biology Society. ISBN: 0-7803-4262-3. The Institute of Electrical and Electronics Engineers, Chicago, EUA, pp. 1946-1949, 1997.
• 55. RISO, R.R., IIGNANI, A.R., KEITH, M.W. Electrocutaneous sensations elicited using subdermally located electrodes. Automedica, v. 11, pp. 25-42, 1989.
• 56. SELKOWITZ, D. M. Improvement in Isometric Strength of Quadriceps Femoris Muscle After Training with Electrical Stimulation. Physical Therapy. v. 65, n. 2, p. 186-196, 1985.
• 57. SEPÚLVEDA, F.; CLIQUET JR., A. A simple auto-adaptive neural circuit for control of human gait: A simulation based on back-propagation. In: Intelligent Engineering Systems Through Artificial Neural Networks, vol. 4, Ed. Dagli, Fernández, Ghosh and Kumara. ISBN:0-7918-045-8. A.S.M.E.Press, New York, EUA, pp. 585-590, 1994.
• 58. SEPÚLVEDA, F.; CLIQUET JR., A. An artificial neural system for closed-loop control of locomotion produced via neuromuscular electrical stimulation. Artificial Organs. ISSN: 0160-564-X. Journal of International Society for Artificial Organs. Blackwell Scientific Publications, Inc., Cambridge, MA, EUA, 19(3), pp. 231-237, 1995
• 59. SEPÚLVEDA, F.; GRANAT, M. H.; CLIQUET JR., A. Gait restoration in a spinal cord injured subject via neuromuscular electrical stimulation controlled by an artificial neural network. The International Journal of Artificial Organs. ISSN: 0391-3988. European Society for Artificial Organs. Wichtig Editore, Milano - Birmingham - Osaka, 21(1), pp. 49-62, 1998
• 60. SEPÚLVEDA, F.; GRANAT, M. H.; CLIQUET JR., A. Two artificial neural systems for generation of gait swing by means of neuromuscular electrical stimulation. Medical engineering & Physics. ISSN: 1350-4533. Biological Engineering Society. Elsevier Science Ltd., Oxford, GB, 19(1), pp. 21-28, 1997.
• 61. SHERRICK, C.E. Basic and applied research on tactile aids for deaf people: progress and prospects. The Journal of the Acoustical Society of America, v. 75, n. 5, p. 1325-42, 1984.
• 62. SZETO, A.Y.J., SAUNDERS, F.A. Electrocutaneous stimulation for sensory communication in rehabilitation engineering. IEEE Transactions on Biomedical Engineering, vol. BME-29, n. 4, p. 300-08, 1982.
• 63. SZETO, A.Y.J.; CHRISTENSEN, K.M. Technological devices for deaf-blind children: needs and potential impact. IEEE Engineering in Medicine and Biology Magazine, p. 25-29, 1988.
• 64. TUREK, S.L. Ortopedia: princípios e sua aplicação. 4a.Edição.SP: Editora Manole, 1991, vol 1.

Publication Dates

• Publication in this collection
  20 Feb 2006
• Date of issue
  Sept 2001