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Scientific
Articles and Abstracts about Pulsed Electromagnetic Field Therapy
PEMF
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The Effect of
Pulsed Electromagnetic Fields in the Treatment of Osteoarthritis of the Knee
and Cervical Spine. Report of Randomized, Double-Blind, Placebo Controlled Trials.
Low-amplitude, extremely low frequency magnetic fields for the
treatment of osteoarthritic knees. A double-blind clinical study.
Magnetic pulse treatment for knee osteoarthritis: a randomised,
double-blind, placebo-controlled study.
Electrochemical therapy of pelvic pain: effects of pulsed electromagnetic
fields (PEMF) on tissue trauma.
Evaluation of electromagnetic fields in the treatment of pain in
patients with lumbar radiculopathy or whiplash syndrome.
We assessed the efficacy and tolerability of low-frequency pulsed
electromagnetic fields (PEMF) therapy in patients with clinically symptomatic
knee osteoarthritis (OA) in a randomised, placebo-controlled, double-blind study
of six weeks' duration.
Pulsed magnetic field therapy and the physiotherapist
Treatment of migraine with pulsing electromagnetic fields: a double-blind,
placebo-controlled study.
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The Effect of Pulsed Electromagnetic Fields in the Treatment
of Osteoarthritis of the Knee and Cervical Spine. Report of Randomized, Double-Blind,
Placebo Controlled Trials
OBJECTIVE. We conducted a randomized, double blind clinical trial to determine
the effectiveness of pulsed electromagnetic fields (PEMF) in the treatment of
osteoarthritis (OA) of the knee and cervical spine. METHODS. A controlled trial
of 18 half-hour active or placebo treatments was conducted in 86 patients with
OA of the knee and 81 patients with OA of the cervical spine, in which pain
was evaluated using a 10 cm visual analog scale, activities of daily living
using a series of questions (answered by the patient as never, sometimes, most
of the time, or always), pain on passive motion (recorded as none, slight, moderate,
or severe), and joint tenderness (recorded using a modified Ritchie scale).
Global evaluations of improvement were made by the patient and examining physician.
Evaluations were made at baseline, midway, end of treatment, and one month after
completion of treatment.
RESULTS. Matched pair t tests showed extremely significant changes from baseline
for the treated patients in both knee and cervical spine studies at the end
of treatment and the one month follow-up observations, whereas the changes in
the placebo patients showed lesser degrees of significance at the end of treatment,
and had lost significance for most variables at the one month follow-up. Means
of the treated group of patients with OA of the knee showed greater improvement
from baseline values than the placebo group by the end of treatment and at the
one month follow-up observation. Using the 2-tailed t test, at the end of treatment
the differences in the means of the 2 groups reached statistical significance
for pain, pain on motion, and both the patient overall assessment and the physician
global assessment. The means of the treated patients with OA of the cervical
spine showed greater improvement from baseline than the placebo group for most
variables at the end of treatment and one month follow-up observations; these
differences reached statistical significance at one or more observation points
for pain, pain on motion, and tenderness.
CONCLUSION. PEMF has therapeutic benefit in painful OA of the knee or cervical
spine.
Trock D. et.al. Department of Medicine, Danbury Hospital,
CT. J. of Rheumatology
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Low-amplitude, extremely low frequency magnetic fields
for the treatment of osteoarthritic knees: a double-blind clinical study.
CONTEXT: Non-invasive magneto-therapeutic approaches to bone healing have been
successful in past clinical studies. OBJECTIVE: To determine the effectiveness
of low-amplitude, extremely low frequency magnetic fields on patients with knee
pain due to osteoarthritis. DESIGN: Placebo-controlled, randomized, double-blind
clinical study. SETTING: 4 outpatient clinics. PARTICIPANTS: 176 patients were
randomly assigned to 1 of 2 groups, the placebo group (magnet off) or the active
group (magnet on). INTERVENTION: 6-minute exposure to each magnetic field signal
using 8 exposure sessions for each treatment session, the number of treatment
sessions totalling 8 during a 2-week period, yielded patients being exposed
to uniform magnetic fields for 48 minutes per treatment session 8 times in 2
weeks. The magnetic fields used in this study were generated by a resonator,
which consists of two 18-inch diameter (46-cm diameter) coils connected in series,
in turn connected to a function generator via an attenuator to obtain the specific
amplitude and frequency. The range of magnetic field amplitudes used was from
2.74 x 10(-7) to 3.4 x 10(-8) G, with corresponding frequencies of 7.7 to 0.976
Hz. OUTCOME MEASURES: Each subject rated his or her pain level from 1 (minimal)
to 10 (maximal) before and after each treatment and 2 weeks after treatment.
Subjects also recorded their pain intensity in a diary while outside the treatment
environment for 2 weeks after the last treatment session (session 8) twice daily:
upon awakening (within 15 minutes) and upon retiring (just before going to bed
at night). RESULTS: Reduction in pain after a treatment session was significantly
(P < .001) greater in the magnet-on group (46%) compared to the magnet-off
group (8%). CONCLUSION: Low-amplitude, extremely low frequency magnetic fields
are safe and effective for treating patients with chronic knee pain due to osteoarthritis.
Jacobson J. et.al. Inst. for Biophysical Research, Jupiter,
FL, USA
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Magnetic pulse treatment for knee osteoarthritis: a randomised,
double-blind, placebo-controlled study.
We assessed the efficacy and tolerability of low-frequency pulsed electromagnetic
fields (PEMF) therapy in patients with clinically symptomatic knee osteoarthritis
(OA) in a randomised, placebo-controlled, double-blind study of six weeks' duration.
While the treated group demonstrated improvement over different indices to the
contrary, the control group demonstrated none. There were no clinically relevant
adverse effects attributable to active treatment. These results suggest that
the unipolar magnetic devices are beneficial in reducing pain and disability
in patients with knee OA resistant to conventional treatment in the absence
of significant side effects.
Pipitone N. et.al. Rheumatology Department, King's College
Hospital (Dulwich), London, UK.
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Electrochemical therapy of pelvic pain: effects of pulsed
electromagnetic fields (PEMF) on tissue trauma.
Unusually effective and long-lasting relief of pelvic pain of gynaecological
origin has been obtained consistently by short exposures of affected areas to
the application of a magnetic induction device. Treatments are short, fasting-acting,
economical and in many instances have obviated surgery. This report describes
typical cases such as dysmenorrhoea, endometriosis, ruptured ovarian cyst, acute
lower urinary tract infection, post-operative haematoma, and persistent dyspareunia
in which pulsed magnetic field treatment has not, in most cases, been supplemented
by analgesic medication. Of 17 female patients presenting with a total of 20
episodes of pelvic pain, 16 patients representing 18 episodes (90%) experienced
marked, even dramatic relief, while two patients representing two episodes reported
less than complete pain.
Jorgensen W. et.al. International Pain Research Institute,
Los Angeles, California.
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Evaluation of electromagnetic fields in the treatment of
pain in patients with lumbar radiculopathy or whiplash syndrome.
Back pain and whiplash syndrome are very common diseases involving tremendous
costs and extensive medical effort. A quick and effective reduction of symptoms,
especially pain, is required. In two prospective randomized studies, patients
with either lumbar radiculopathy in the segments L5/S1 or whiplash syndrome
were investigated. Electromagnetic devices are pulsed field (PEMF) and constant
wave (CW) types. These studies indicate both are effective, PEMF usually more
quickly than CW. Pulsed magnetic fields appear to have a considerable and statistically
significant potential for reducing pain in cases of lumbar radiculopathy and
whiplash syndrome.
Thuile Ch. et.al. International Society of Energy Medicine,
Vienna, Austria.
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We assessed the efficacy and tolerability of low-frequency
pulsed electromagnetic fields (PEMF) therapy in patients with clinically symptomatic
knee osteoarthritis (OA) in a randomised, placebo-controlled, double-blind study
of six weeks' duration.
Patients with radiographic evidence and symptoms of OA (incompletely relieved
by conventional treatments), according to the criteria of the American College
of Rheumatology, were recruited from a single tertiary referral centre. 75 Patients
fulfilling the above criteria were randomised to receive active PEMF treatment
by unipolar magnetic devices or placebo. Six patients failed to attend after
the screening and were excluded from analysis. The primary outcome measure was
reduction in overall pain assessed on a four-point Likert scale ranging from
nil to severe. Secondary outcome measures included the WOMAC Osteoarthritis
Index (Likert scale) and the EuroQol (Euro-Quality of Life, EQ-5D). Baseline
assessments showed that the treatment groups were equally matched. Although
there were no significant differences between active and sham treatment groups
in respect of any outcome measure after treatment, paired analysis of the follow-up
observations on each patient showed significant improvements in the actively
treated group in the WOMAC global score (p = 0.018), WOMAC pain score
(p = 0.065), WOMAC disability score (p = 0.019) and EuroQol score
(p = 0.001) at study end compared to baseline. In contrast, there were
no improvements in any variable in the placebo-treated group. There were no
clinically relevant adverse effects attributable to active treatment. These
results suggest that PEMF magnetic devices are beneficial in reducing pain and
disability in patients with knee OA resistant to conventional treatment in the
absence of significant side-effects. Further studies using different types of
magnetic devices, treatment protocols and patient populations are warranted
to confirm the general efficacy of PEMF therapy in OA and other conditions.
Nicolò Pipitone, David L. Scott
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Pulsed magnetic field therapy and the physiotherapist
The therapeutic effect of the application of pulsed magnetic field therapy (PMFT)
has at last received world-wide recognition, although for a long time many practitioners
saw it only as an aid to fracture union. Research has now shown that it has
the potential to improve a wide range of conditions, although few understood
just how it achieved its effectiveness. Extensive research has since been carried
out to determine the mechanism by which this occurs. For the physiotherapist,
presented with a wide range of clinical problems, PMFT is an invaluable aid
to the clinic.
Resolution of soft tissue injuries:
Over the past few years, research has shown that its effectiveness is not through
heat production - as is the case with some modern treatments - but is at the
cellular level. One significant outcome of this is the effect it has on soft
tissue injuries. As early as 1940 it was suggested that magnetic fields might
influence membrane permeability. It has since been established that magnetic
fields can influence ATP (Adenosine Tri-phosphate) production; increase the
supply of oxygen and nutrients via the vascular system; improve the removal
of waste via the lymphatic system; and help to re-balance the distribution of
ions across the cell membrane. Healthy cells in tissue have a membrane potential
difference between the inner and outer membrane. This causes a steady flow of
ions through its pores. In a damaged cell the potential is raised and an increased
and an increased sodium inflow occurs. As a result, interstitial fluid is attracted
to the area, resulting in swelling and oedema.
The application of PMFT to damaged cells accelerates the re-establishment of
normal potentials (Sansaverino) increasing the rate of healing and reducing
swelling. This can help to disperse bruising also. A magnetic field pulsed at
5Hz with a base frequency of 50Hz can have the same effect as an ice pack in
that in that it causes vasoconstriction.
Effects on fracture repair:
Acceptance of magnetic fields in medicine came about foremost in the field of
orthopedics. Low frequency and low intensity fields have been used extensively
for the treatment of non-union fractures. By 1979 this method was approved in
the USA as a safe and effective treatment for non-union fractures; for failed
arthroses; and for congenital pseudo-arthroses. According to Bassett this method
has been used by more than 6,000 surgeons. The success rate was over 80% for
tibial lesions. No patient suffered complications and biological side-effects
included improved healing and increased neural function. In-depth research carried
out to investigate this, shows that magnetic fields influence the process of
bone formation in the intercellular medium. Madronero showed that bone healing
was promoted by means of the influence of the magnetic field on the crystal
formation of calcium salts.
Pain reduction:
Pulsed magnetic field therapy has been shown to bring about a reduction of pain,
which again is due to action at the cellular level. Pain is transmitted as an
electric signal, which encounters gaps at intervals along its path. The signal
is transferred in the form of a chemical signal across the synaptic gap and
this is detected by receptors on the post-synaptic membrane. A charge of about
-70mV exists across the inner and outer membranes, but when a pain signal arrives
it raises this to +30mV. This action causes channels to open in the membrane,
triggering the release of a chemical transmitter and allowing ions to flow into
the synaptic gap. The cell then re-polarizes to its previous resting level.
Research by Warnke suggests that PMFT affects the quiescent potential of the
membrane, lowering it to a hyper-polarized level of -90mV. Transmission is effectively
blocked since the pain signal is unable to raise the potential to the level
required to trigger the release of the chemical transmitter. Again, the frequency
of the applied magnetic field is important, as the most effective frequency
to produce this effect was found to be a base frequency of 100Hz pulsed at between
5 and 25 pulses per second.
Clinical applications:
The value of pulsed magnetic field therapy has been shown to cover a wide range
of conditions, with well documented trials carried out by hospitals, rheumatologists
and physiotherapists. For example, the department of rheumatology at Addenbrookes
Hospital carried out investigations into the use of PMFT for the treatment of
persistent rotator cuff tendinitis. The treatment was applied to patients who
had symptoms refractory to steroid injection and other conventional treatments.
At the end of the trial, 65% of these were symptom free, with 18% of the remainder
being greatly improved.
Lau (School of Medicine, Loma University, USA) reported on the application of
PMFT to the problems of diabetic retinopathy. Patients were treated over a 6-week
period, 76% of the patients had a reduction in the level of numbness and tingling.
All patients had a reduction of pain, with 66% reporting that they were totally
pain-free. Many research studies, including Lau, reported on the application
of PMFT for conditions such as sports injuries and for patients with joint and
spinal problems. Although these are too numerous to mention individually, in
almost every instance there was a reduction, if not complete resolution of symptoms.
Soft tissue injuries and joint pains tended to be resolved within 5 days of
treatment. Patients with cervical problems and low back pain were also successfully
treated, whereas previous treatment with ice, traction and other therapies had
been unsuccessful. In yet another trial, the effect of applying PMFT to sufferers
of Multiple Sclerosis was investigated (Geseo) 70% of sufferers had a reduction
of weakness, pain and spasticity, with 50% reporting improvement of their bladder
incontinence. Through the evaluation of hundreds of research papers, a number
of points have been established regarding PMFT: The field must be pulsed, with
low frequency to achieve the best effect.
Different conditions require different frequencies. For example, 5Hz causes
vasoconstriction whilst 10Hz and above causes vasodilatation. Biological effectiveness
is achieved in just 10 minutes for most injuries, so that long treatment sessions
are not required. When used at the correct level there are no recorded side
effects. Although PMFT is not yet recommended for use during pregnancy or in
the presence of tumors, there are papers to suggest that magnetic fields can
inhibit the growth of tumors.
Dr. D. C. Laycock, Ph.D. Med. Eng. Westville Consultants
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Treatment of migraine with pulsing electromagnetic fields:
a double-blind, placebo-controlled study.
The effect of exposure to pulsing electromagnetic fields on migraine activity
was evaluated by having 42 subjects (34 women and 8 men), who met the International
Headache Society's criteria for migraine, participate in a double-blind, placebo-controlled
study. During the first month of follow-up, 73% of those receiving actual exposure,
reported decreased headaches (45% substantial decrease, 14% excellent decrease)
compared to half of those receiving the placebo (15% worse, 20% good, 0% excellent).
Ten of the 22 subjects who had actual exposure received 2 additional weeks of
actual exposure, after their initial 1-month follow-up. All showed decreased
headache activity (50% substantial, 38% excellent). Eight of the subjects in
the placebo group elected to receive 2 weeks of actual exposure after the initial
1-month follow-up with 75% showing decreased headache activity (38% substantial,
38% excellent). In conclusion, exposure to pulsing electromagnetic fields for
at least 3 weeks is an effective, short-term intervention for migraine.
Sherman R. et.al. Orthopedic Surgery Service, Madigan Army
Medical Center, Tacoma, WA, USA.
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