Electrotherapy
Electrical Stimulation Devices
Large tabletop clinical units:
-
Smaller portable units:
Biphasic Symmetrical
speed and total amount of current flow are the same in 2 phases
Biphasic Asymmetrical
- speed of curret flow is different for each [hase
- balence total amount of current flow for 2 phases is the same
- unbalenced total amount of current flow for the 2 phases is different
Interferential Current
- produce bby interference of two medium frequency ACs with slighty different frequecies
- Interference of these ACs produces cyclically increasing and decreasing amplitude waves
- freq cycle called the beat freq is = to the differece between the freqs of 2 ACs
- ex AC of 4000 Hz interfering with another of 4100 Hz will produce a beat freq of 100 Hz
- medium fre rang 1000- 10000
Direct Current
-current flow eqully throughout the stimulation
- includes only amplitude and total treatments time
Russian Stimulation
AC delivered in the burst between 1000 10000 Hz and burst. freq between 1-100 burst per second
Pulsed Currents
- pulse duration/ phase duration
- frquency
- on and off time
- ramp u and ramp down time
- amplitude
Phase Duration
- period when electical current flows in one direction
- How long a phase last measured in microseconds
Pulse Duration
-period when electrical current flows in any direction
-How long a pulse last from the beginning of the first phase of the pulse to the end of the last phase of the pulse, measured in microseconds
Interpulse interval
the amount of time between pulse
Frequency
number of cycles or pulses per second, mesured in Hz or pulse per second
Amplitude
- magnitude of current flow
- also called strength or intensity
- Measured in amps or volts
on/off times
on- the seconds when current is on
off- the seconds when the current is off
- ratio 10 sec on 50 sec off; 10:50 sec on:off time
or 1:5 on:off
Ramp Up and Ramp Down
UP- the number of seconds it takes for the current amplitude to increase from zero during off time to max amp of the on time
Down sec take for current amp to ecrease from max to zero
resting Membrane potential
electrical potential difference between the inside of neuron and the outside of the neuron when it is at rest
- (-60 to -90 mV)
-
Strength duration
Graphic rep of the min combination of amp and duratgion that is sufficient to produce an actio n potential in a nerve
Amp and duration of electrical current
need to generate an AP depen on the type of neve being stimulated
- lower currents and shorter puls duration can stimulate APs in sensory nerves
higher and longer needed to stim motor
Ionic effects
- can leave a charge in the body that have ionic effect
- dir current, pulsed mono cur or
Contraindacations
- Demand pacemakers
- defibrillator
- unstable arrythmia
- over carotid sinus
- over venous arteriothrombosis
- pregnancy
Precutions
cardiac diseases
- impaired sensation or menttation
- malignancy
- Skin irritation/ wounds
Adverse effects
-burns
- skin irritation
- pain
Innervated Muscle
-When action potentials (APs) are propagated along motor nerves
- fast twitch type 2 muscle fibers are activated
Denervated Muscle
- When a muscle becomes denervated by nerve injury or disease, it no longer contracts physiologically, and a contrac- tion cannot be produced by the amount of charge that is effective for an innervated muscle.
Physiologically Stimulated Contractions
- slow twitch type 1 muscle fiber contract first: low contraction force, slow speed of contraction, fatigue resistance, Atrophy resistance
- Asychronouse Recruitment
Electrally Stimulation Contractions
-Fast twitch type 2 muscle fibers contract first: high contraction force, fast speed of contraction, fatique quicky, Atrophy quickly
-sychronous recruitment
Over load princable
the greater the load placed on a muscle and the higher-force contraction it produces, the more strength that muscle will gain.
Specificity
-muscle contractions specifically strengthen the muscle fibers that contract.
-es has more effect on type 2 uscle fibers than on type 1
- disuse atrophy is primarily of type 2 fibers
Clinical Applications
1. MUSCLE STRENGTHENING FOR PATIENTS WITH ORTHOPEDIC CONDITIONS
2. CARDIORESPIRATORY AND FUNCTIONAL TRAINING FOR PATIENTS WITH CARDIAC, PULMONARY, OR CRITICAL ILLNESS
3. MUSCLE STRENGTHENING FOR ATHLETIC PERFORMANCE
4. COUNTERACT DECONDITIONING IN OLDER ADULTS
5. IMPROVED MUSCLE COORDINATION AND MOTOR CONTROL IN PATIENTS WITH NEUROLOGICAL CONDITIONS
6. RETARDATION OF ATROPHY AND
RETURN OF FUNCTION IN DENERVATED MUSCLE
7. EDEMA CONTROL AND IMPROVED CIRCULATION
Application Techniues
Electrode Placement
- one electrode over motor point
-other electrode over stimulated muscle aligned paraell to muscle fiber direction
-electrodes at least 2 inches apart
patient positioning
-keep joint in mid range
- isometric or isotonic contraction
wave form
to produce a muscle contraction either a pulsed biphasic waveform or or Russian protocol should be used.
Current Amplitude and pulse duration
- amp: contraction 10% to 50% MVIC of uninjured side
- pulse: 125 -350
Setting up frequency
- 35 to 50 pps, for larger muscle
- 20 to 30 pps for smaller muscles
- 50 to 80 may ot only increase muscle stength but also fatique
setting up On:Off and Ramp time
- on 6 to 10 secs
- off 50 -120 sec
ramp up and down 1 to 4 secs