Electrotherapy Basics

Question 1

What’s the difference between resistance and impedance? They both refer to opposition of movement.

Answer 1

R = DC current
I = AC current

Question 2

Can DC current be biphasic?

Answer 2

No, it can’t switch polarity by definition.

Question 3

Iontophoresis is used to ___? What current type?

Answer 3

Stimulate denervated muscles; wound healing.

DC current.

Question 4

DC current + or - polarity can create a chemical reaction. The oxidation of + or - ions result in ___ and ___ reactions respectively.

Answer 4

Acidic (scleroitc - toughening agent).

Alkaline (sclerolytic - softening agent).

Question 5

Does DC current have an interruption to its amplitude?

Answer 5

No.

Question 6

Used for strengthening, ___ is delivered at 2,500 Hz in bursts of 50.

Answer 6

Russian protocol.

Question 7

For what 3 types of stimulation is bimodal AC current typically used?

Answer 7

1. Inferential
2. Premodulated
3. Russian protocol

Question 8

What is the key characteristic of pulsed currents?

Answer 8

They are interrupted DC or AC (biphasic/bidirectional) currents

Question 9

Russian current and TENS are measured in ___, while pulse/cycle duration is measure in ___.

Answer 9

Bursts per minute (bups).

Beats per minute (bps).

Question 10

List and describe the 3 clinical uses of electrical stimulation.

Answer 10

1. Ameliorating muscle dysfunction. NMES (MedFq burst AC or Russian) for activation of muscle through stimulation; NM re-education.
   - Dec muscle spasms & spasticity.
2. Pain suppression (electroanalgesia). TENS (transcutaneous electrical nerve stimulation) or inferential current. ESTR (electrical stimulation for tissue repair).
3. Control inflammation and tissue repair. DC current, HVPC (high volt pulsed control).

Question 11

Name the contraindication for ESTIM.

Answer 11

1. Implanted electrical pacing devices (cardiac demand pacemaker, bladder stimulator)
2. Over pregnant uterus
3. Over superficial metal implants
4. Severely impaired sensation
5. When active motion is contraindicated - if stimulating for a muscle contraction (acute fracture)
6. Active bleeding in area being stimulated
7. Over malignancies
8. Phlebitis
9. Over transthoracic or anterior cervical area
10. Placement of electrodes over carotid sinus

Question 12

Name the precautions for ESTIM.

Answer 12

1. Open wounds or broken skin in treatment area
2. Extreme edema
3. Unreliable patients
4. Cardiac disease
5. Malignant tumors

Question 13

What is the minimum required distance for electrode placing?

Answer 13

2 inches or 5 cm.

Question 14

The most commonly used ESTIM on/off cycle ratio that doesn’t result in fatigue is ___?

Answer 14

1:2/3 (6 seconds on, 12-18 seconds off).

Question 15

When would you use reciprocal stimulation, and what is it?

Answer 15

Used with 2 channels; alternate stimulation.

Question 16

Small electrodes have ___ current density?

Answer 16

Greater.

Question 17

What areas are good for placing electrodes?

Answer 17

• Over motor points for stimulation of muscles for contraction.
• Over areas of pain, along dermatomes , referral patterns for electroanalgesia, transarthrally (across a joint)

Question 18

As electrode distance increases, current penetration depth ___?

Answer 18

Increases.

Question 19

What are the typical time guidelines for electroanalgesia and iontophoresis?

Answer 19

E: 20-30 minutes.
I: 10-20 minutes.