"What are Modalities? And What
do they do?"
Modalities refer to a wide range
of devices ranging from ice to electrical muscle stimulators
that are used to provide a therapeutic intervention for
an array of musculoskeletal conditions. Ice was discussed
in a previous article ('First Aid Tips'), so I will discuss
some of the other common modalities, which are utilized
within the physical therapy clinic.
Ultrasound
This is the production of longitudinal mechanical sound
waves above the audible range (20 kHz). The frequencies
used in physical therapy vary from 1.0 to 3.0 MHz. The depth
of penetration ranges from 3 mm to 5 mm below the surface
of the skin depending on which frequency is used. The sound
waves produced by the sound head require a medium to penetrate
into the tissue so it is commonly applied with a bluish
gel-like substance. Ultrasound is thought to promote chemical
mediators, which promote tissue healing. There is also an
increase in circulation and an increase in cellular activity
of substances that promote a reduction in edema. This also
accelerates the healing process and results in pain relief.
Ultrasound may be used in recent soft-tissue injuries (e.g.
tendonitis, muscle strains, ligament sprains), recent and
chronic scar tissue, and venous ulcers and pressure sores,
to name just a few of the uses. The only sensation that
may be felt is a deep heat in the area in which the ultrasound
is applied and, contrary to what was believed in the past,
there is no danger of tissue burn, no matter what the intensity.
Therapeutic Electrical
Muscle Stimulation (EMS)
This term can encompass a wide range of devices. The devices
used commonly in our clinic are TENS, NMES, and HVPC. They
can be both stationary and portable devices. Within our
clinic the devices tend to be of the portable model with
many patients having rental units for use away from the
clinic. Attached to the small portable base units are one
or two lead wires which connect to, anywhere from two to
four self-adhesive surface electrodes, which are applied
to the skin surface. Though applied in roughly the same
manner, they each represent a therapeutic intervention for
a variety of clinical symptoms as well as an unattended
treatment technique.
· TENS (Transcutaneous Electrical Nerve Stimulation)
Is most commonly associated with portable stimulators that
the patient can utilize whenever they experience pain or
discomfort and they are not in the clinic. TENS units are
comparable in size to a cassette tape. They are battery-operated
stimulators that are capable of providing sensory or motor-level
stimulation for pain management.
· NMES (Neuromuscular Electrical Stimulation)
These units are utilized for the reduction of muscle spasm,
muscle strengthening, and potentially for edema reduction
via muscle pumping. NMES devices deliver electrical stimulation
across the skin the same way that TENS devices do, but the
treatment goal is a motor response (muscle contraction)
rather than a sensory analgesia response (pain relief).
· HVPC (High Voltage Pulsed Current)
This device was named for its output parameters, which allowed
voltage output levels of up to 500 V. HVPC is utilized for
a variety of therapeutic applications, including pain reduction,
muscle spasm reduction, edema reduction, and muscle re-education.
Surface stimulation is used with this device as well, which
enables this unit to be used as both a TENS and NMES device.
Current research has led to resurgence in the devices particularly
for edema reduction and wound healing and is probably the
most utilized electrical stimulation device in our clinic.
This is providing just a brief
overview of some of the more common modalities that are
used in physical therapy clinics. If you have any further
questions regarding these modalities, feel free to contact
us at C.O.A.S.T. Rehab and we will gladly try to answer
any questions/concerns you may have.
