6. MUSCLE STIMULATOR
6.1 INTRODUCTION
The neuro-muscular stimulator stimulates the nerves (neurons) of the part of the body to which the electrodes are attached. It provides relief for headache, muscular pain, or fatigue (due to exertion of muscles) and also revives the frozen muscle which impairs movement. The main function of this electronic instrument is to provide energy to nerve of the muscle and to remove cellulites.
Current stimulator is one of the most commonly used instruments used for diagnosis and treatment of a wide variety of neurological and muscular disorders. It works by forcing electric current into a human system, to elicit information to treat the system.
The muscular stimulator circuit generates 150 µs pulses at 80 Hz frequency, which is then given to the secondary of the transformer to generate 60V positive and 150V negative peaks at very low current so that the patient in not subjected to any shock. The intensity of the current can be varied by changing the resistance which is connected to the pulse generator. Pulse generator is the heart of the circuit involves CMOS timer (7555) to generate pulse train.
Electric muscular stimulation may be unsuitable for subjects with acute pathologies. It should be avoided in the case of epilexy, osteoporosis or bone tumour, arterial hypertension, pregnancy, cancer, skin pathologies, pacemakers, cardiopathies or arrythmia (never apply to the heart), kidney deficiency and under treatment of beta blocking drugs. Electrical stimulation is simply the application of electrical pulses to the body, for performing a function or therapy. The classical example is that of the cardiac pacemaker. The range of uses of electrical stimulation is wide and include.
Pain relief (often known as TENS - Transcutaneous Electrical Nerve Stimulation)
Maintaining and increasing range of movement
Muscle strengthening
Facilitation of voluntary motor function
Neuro-Muscular stimulator (NMS)
Neuro-Muscular stimulator (NMS) is a subset of electrical stimulation. The term NMS is applied to systems which attempt to restore lost or impaired neuromuscular function, such as standing and walking in case of paraplegia, by the application of electrical pulses to neural pathway or, but less often, directly to muscles.
Principal of NMS
At the electrode-tissue interface a conversion occurs between the current of electrons passing through the wires and the current of ions moved within the tissue. Then through this externally applied current, the depolarization of nerve and muscle to threshold is produced by transport of ions across the tissue membrane.
The factor determining whether the sufficient current flows to cause an action potential are:
Impedance of body tissue
Electrode size and position
Stimulation parameter
The conductivity of body tissues is related to their water and ion content. Muscle is a good conductor, but conduct much better in the longitudinal direction of its fiber than in transverse one, while adipose tissue is a good insulator.
Thus the electrode position can affect the current required for stimulation. With surface electrical stimulation the effect of electrical current (the current density) diminishes with depth of tissue.
A nerve will be stimulated when the transmembrane potential is reversed by an externally applied current. Indeed, the potential need only be reduced by about 30% for an action potential to be generated. Because the membrane has capacitance it will require a finite charge to change the transmembrane potential.
The energy require top stimulate all types of nerve fiber is not the same. A large nerve fiber has a lower threshold to stimulation than a small fiber, i.e. less energy is required, and also has a faster conduction velocity.
If the nerve supply to a muscle is cut than muscle will slowly die. An electrical stimulus can still be used to stimulate the muscle directly, rather than by stimulating the nerve, but the threshold is increased. If the muscle is denervated than greater energy is required to stimulate the muscle.
6.1 INTRODUCTION
The neuro-muscular stimulator stimulates the nerves (neurons) of the part of the body to which the electrodes are attached. It provides relief for headache, muscular pain, or fatigue (due to exertion of muscles) and also revives the frozen muscle which impairs movement. The main function of this electronic instrument is to provide energy to nerve of the muscle and to remove cellulites.
Current stimulator is one of the most commonly used instruments used for diagnosis and treatment of a wide variety of neurological and muscular disorders. It works by forcing electric current into a human system, to elicit information to treat the system.
The muscular stimulator circuit generates 150 µs pulses at 80 Hz frequency, which is then given to the secondary of the transformer to generate 60V positive and 150V negative peaks at very low current so that the patient in not subjected to any shock. The intensity of the current can be varied by changing the resistance which is connected to the pulse generator. Pulse generator is the heart of the circuit involves CMOS timer (7555) to generate pulse train.
Electric muscular stimulation may be unsuitable for subjects with acute pathologies. It should be avoided in the case of epilexy, osteoporosis or bone tumour, arterial hypertension, pregnancy, cancer, skin pathologies, pacemakers, cardiopathies or arrythmia (never apply to the heart), kidney deficiency and under treatment of beta blocking drugs. Electrical stimulation is simply the application of electrical pulses to the body, for performing a function or therapy. The classical example is that of the cardiac pacemaker. The range of uses of electrical stimulation is wide and include.
Pain relief (often known as TENS - Transcutaneous Electrical Nerve Stimulation)
Maintaining and increasing range of movement
Muscle strengthening
Facilitation of voluntary motor function
Neuro-Muscular stimulator (NMS)
Neuro-Muscular stimulator (NMS) is a subset of electrical stimulation. The term NMS is applied to systems which attempt to restore lost or impaired neuromuscular function, such as standing and walking in case of paraplegia, by the application of electrical pulses to neural pathway or, but less often, directly to muscles.
Principal of NMS
At the electrode-tissue interface a conversion occurs between the current of electrons passing through the wires and the current of ions moved within the tissue. Then through this externally applied current, the depolarization of nerve and muscle to threshold is produced by transport of ions across the tissue membrane.
The factor determining whether the sufficient current flows to cause an action potential are:
Impedance of body tissue
Electrode size and position
Stimulation parameter
The conductivity of body tissues is related to their water and ion content. Muscle is a good conductor, but conduct much better in the longitudinal direction of its fiber than in transverse one, while adipose tissue is a good insulator.
Thus the electrode position can affect the current required for stimulation. With surface electrical stimulation the effect of electrical current (the current density) diminishes with depth of tissue.
A nerve will be stimulated when the transmembrane potential is reversed by an externally applied current. Indeed, the potential need only be reduced by about 30% for an action potential to be generated. Because the membrane has capacitance it will require a finite charge to change the transmembrane potential.
The energy require top stimulate all types of nerve fiber is not the same. A large nerve fiber has a lower threshold to stimulation than a small fiber, i.e. less energy is required, and also has a faster conduction velocity.
If the nerve supply to a muscle is cut than muscle will slowly die. An electrical stimulus can still be used to stimulate the muscle directly, rather than by stimulating the nerve, but the threshold is increased. If the muscle is denervated than greater energy is required to stimulate the muscle.
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