Electric and Magnetic Stimulation

Proprioceptive Neuromuscular Facilitation With Electrical Stimulation

Pavla Obrezar, Marko Munih2, Helika Benkolrlnstitute for Rehablitation of Republic of Slovenia, Linhartova 51, 1000 Ljubljana, SLOVENIA

2 Faculty of Electrical Engineering, University of Ljubljana, TrZaSk a 25, 1000 Ljubljana, SLOVENIA

209@

Abstract: The aim of Proprioceptive NeuromuscularFacilitation (PNF) method ,s to promote functionalm ov e m e nt of p ar alyz e d I im b t hr ough fac i I it at i o n, inhib it i on,strengthening, and relaxation of muscle groups. The

handicapped person produce the movement, which licombined with a properly graded resistance, fitted to thepatient's needs by a physiotherapist. New additionintroduced here, is the ossistance of surface functionalelectrical stimulation during some movement patterns of theleg (e.g. Jlexion-adduction-external rotation). Customizedelectrical stimulator was mounted inside a leg pedalhousing, enabling precise control of stimulation amplitude.

INTRODUCTION

PNF is a well-conceived physical therapy modalitydeveloped in the 1940s and 1950s to rehabilitate patientswith paralysis as a result of neurological dysfunction. In the1980s, sport therapists began using the stretchingcomponents of PNF with healthy athletes to increase theirrange of motion, to improve performance and to reduce therisk of injury. The PNF is observed more than a technique,it is a philosophy of treatment. Each treatment is directed ata total human being, not at a specific problem or bodysegment. The basic facilitation procedure provides the toolsfor the therapist to help the patient gaining efficient motorfunction. The effectiveness does not depend on consciouscooperation of patient. The desired motor response ingeneral, smooth, coordinated and optimal muscle pattern is

consisting of both isometric and isotonic contractions. InPNF there are used resistance, irradiation andreinforcement, manual contact, stretch, guidance andcontrol, traction, verbal commands, vision and timing.Resistance is used to aid muscle contraction, supervisemotor control and increase strength. Inadiation andreinforcement rely on spread of response to stimulation.Manual contact is used to increase strength and guidemotion with grip and pressure. Stretch action assists muscleelongation and provokes stretch reflex in order to facilitatecontraction and decrease muscle fatigue. Guidance andcontrol of the provoked movement trajectory by the finealignment of therapist's body arms and hands are here toassist to achieve desired pattern and timing of motion.Verbal instructions and visual information stimulate thepatient for maximal active cooperation. The commondenominator in PNF is always the patient's voluntarymediated, complex activify in several joints resulting (mostfrequently) in limb movement.

In the cases with severe neuromuscular dysfunction, therange of motion or the achieved performance in general is

not adequate if compared to the patient intention, desire orpsychical effort during the exercise. In these cases the

assistance with Functional Electrical Stimulation seems tobe a valuable addition to achieve: (i) instant improvementof motor response, (ii) steady and marked progress of thehealth condition, (iii) last, however very important the helpto the physiotherapist. This introductory study usedmodified one channel electrical stimulator. Prior to thesession is required that the physiotherapist adjusts themaximal desired amplitude. Latter, during the PNF training,while is the physiotherapist still being involved with thepatient by classical PNF means, in addition also controlsthe stimulator amplitude with the leg pedal from nullamplitude up to the previously adjusted 100 7o level. Insuch a way the physiotherapist supervises the timing andthe "degree of help" needed in particular moment.

METHODS AND RESULTS

FES stimulator

For PNF task was developed simple microprocessorbased stimulator with surface electrodes. Minimumrequired maintenance, easiness of use and the compliancewith EC requirements were among design goals. Toenhance versatility and accommodate the device toindividual needs, the stimulator enable adjustment ofstimulation parameters including: pulse width, stimulationfrequency and amplitude, which can be set by the clinicianvia PC computer or a simple external module in advance orduring stimulation if necessary. External module enablescommunication with the user via two pushbuttons and LEDbar display. The frequency may be preset at [ 5 20 25 30 4050 70 1001 Hz, stimulation pulse width at [150 200 250 300350 400 500 600 7001 ps and stimulation pulse amplitudefrom 0 up to 135 V. Stimulation level is adjusted with twopotentiometers. The potentiometer, mounted aside of thehousing, is used to set the overall maximum stimulationamplitude. This is preset when the pedal is fully pressed

down. The second potentiometer mounted on the pedalplate is adjusting stimulation amplitude from 0 up to themaximal level adjusted before. Amplitude is low when thepedal is in upward position. In this upward position is theDC/DC converter switched off automatically via hiddencontact-less reed relay. Such ON/OFF operation regime issignifi cantly extending battery life.

The device use is for the physiotherapist very simple;additional controls, not mentioned before, include onlyON/OFF switch and connector for electrodes. Externalparameter adjustment module, if needed, can be connectedvia DB9 connector on the side of pedal. The unit is meantto stay on the floor and is operated (stimulation amplitudemodulated) during a session with a foot only. The lowbattery situation is indicated with a beep signal.

3*o InrenNATroNAL ConreRrncE oN BrorucrRoMAGNETrsM8-12 October 2000, Bled - SLOVENIA

2L0

Figure l: PNF stimulator

PNF application

When treating neuromuscular dysfunction, complexmotor patterns are reduced to their basic movement and

developmental components. The emphasis is placed uponselective reeducation of individual motor elements, throughdevelopment of the fundamental skills of the limb control,stability and coordinated mobility. Possible exampleincludes electrode pair placement on the calf s orequivalently on the peroneal nerve under the knee, bothplaces being appropriate to elicit the flexion of knee joint.Such electrode placement is suitable for the leg flexion-adduction-external rotation task, when the therapist inaddition to normal PNF practice, as described inintroduction section, also varies stimulation level via the legpedal (stimulator). These basic motor skills are later builtupon by more functional activities. Each movement is

reinforced through repetition and at the beginning highdegree of FES assistance, which through time graduallydecreases.

CONCLUSIONS

This presentation outlines the PNF stimulator with simpleoperation, robust design, adjustable parameters and goodenergy efficiency. To make it as simple as possible, thenumber of controls was reduced to a minimal possiblenumber. Secondly, depicted is application of therapeuticelectrical stimulation for leg (knee) flexion-adduction-external rotation task pattern in PNF practice. This exampleof electrical stimulation in PNF training is giving only onepossible pattern for both, previously separated techniques,however several other movement patterns with this mergedapproach are possible.

Electric and Magnetic Stimulation

Figure 2: FES assisted PNF training

REFERENCES

[] S. Adler, PNF in practice: an illustrated guide. Berlin:Springer, 1993.

[2]8. Ott, M. Munih, A. Kralj, "Voluntary controlledperoneal stimulator," in Proc. Int. Conf IEEE Engineer-ing in Medicine and Biolog,,. Atlanta, Georgia, 1999.

t3] E. Ott, A. Kralj, "Wireless-controlled portable peronealstimulator," in Proc. IEEE Int. Symp on IndustrialElectronics. Bled, Slovenia, 1999.

[4] M. Munih, P. Obreza, E. 9tt, H. Benko, "PNF ElectricalStimulator," in Proc. 4'n IFESS Conference, Sendai,

Japan, 1999.

3*o InrrnNATroNAL CorurenencE oN BroelecrRoMAGNETrsMB-12 October 2000, Bled - SLOVENIA

100% omplitude