Week 13 EMG, Laser, Diathermy, and Alternative Approaches Flashcards
what is electromyography (EMG)?
the summation of all motor unit action potentials that a sensor can record from the muscle(s) underneath the sensor
what does a higher EMG amplitude indicate?
there is more motor unit recruitment or motor units are firing at a higher rate (or both)
how does skin impedance and subcutaneous structures affect EMG?
if there is a high impedance the signal will decrease
when should you use EMG biofeedback? list some examples.
-to increase muscle activity (motor learning, muscle reeducation, postural training)
-to decrease muscle activity (decrease muscle guarding, relaxation, muscle reeducation)
where should the EMG sensor be placed?
the muscle belly
what are the two modes of EMG biofeedback?
-above threshold: machine will give auditory/visual feedback when the muscle activity is above the threshold
-below the threshold
what are the contraindications of EMG biofeedback?
none
what are the precautions of EMG biofeedback?
-open wound
-fragile skin (due to adhesives)
-allergy to adhesive materials or gel
not applicable in patients with sever cognitive impairments due to it requiring cooperation
what does laser stand for?
light amplification by stimulated emission of radiation
what are the three characteristics of laser that differentiate it from other light sources?
-monochromatic: all photons have a single wavelength and, thus, a single color (or invisible)
-coherent: all photons travel in the same phase and direction
-collimated (parallel): minimal divergence over distance
what does wavelength determine in laser?
the depth of penetration
what is incident power?
how much of the laser the body will receive
what are the two different types of low power laser?
-helium-neon: gaseous; wavelength 400-700nm; visible; lower penetration
-gallium-arsenide: semiconductor; wavelength 600-1200nm; invisible; higher penetration
what is the optical window of the skin?
we want the laser to penetrate through the skin and water level to be absorbed by the tissue
600-1200nm
how is depth of penetration measured?
the depth at with the 60% of applied energy has been absorbed and 40% is still extending deeper into the tissue
what is the optimal wavelength used for effective depth of penetration?
*830nm - infrared 50-60nm
what are the effects of laser therapy?
-reduce excitability of nervous tissue
-increased vascularity
-reactivate enzyme
-increase APT release
(all above for pain control)
-stimulate collagen production
-increased RNA and DNA synthesis
-increased lymphatic drainage
-stimulate fibroblastic activity
-increased phagocytosis
how is laser classified?
-class I: cd player
-class II: laser pointer/therapeutic
-class IIIA: therapeutic
-class IIIB: therapeutic
-class IV: therapeutic, surgery
what are the contraindications/precautions for laser?
-over the eye
-epilepsy
-fever
-near cancerous lesions
-pregnant women (abdominal area)
-active hemorrhage area
-over endocrine glands
-photosensitive
what are the indications for laser?
-pain
-inflammation
-wound
-trigger point
-arthritis
-fracture
what is diathermy?
high frequency electromagnetic waves penetrate into the body; increases energy of tissues and cells
what are the two types of diathermy?
-microwave (300MHz-300GHz): more focal (hot spot) and superficial (skin burn)
-short wave(10-100MHz; FCC assigned 13.56, 40.68, and 27.12MHz): high frequency, short wavelength (11 meter), deeper, continuous or pulsed
what is inductive diathermy?
-drum or sleeve
-increase heating of muscle
-less heating of connective tissue
what is capacitive diathermy?
-series: treated area between plates; high impedance tissue (fat)
-parallel: both plated over treated area; low impedance tissue (muscle)
