Interventions Exam 2: EMG and Biofeedback

define EMG

electromyography: diagnostic tool, quantifies muscle tone via recording electrical activity, can be used to provide biofeedback

define biofeedback

provides information to the individual on their physiological or biomechanical processes in order to allow for improved function (targeted process) and performance

define direct biofeedback

accurate, numerical value

heart monitor, brain waves, respiratory rate

define transformed biofeedback

representative signal of muscular activity (EMG)

detects the muscle activity and converts it to extrinsic auditory, visual, or tactile feedback

define peak amplitude

highest EMG activity during muscle contraction

define contraction latency

amount of time to reach peak amplitude

define return latency

time from peak amplitude to baseline level

define hold capacity

time during which consistent EMG amplitude is observed; reflects mm. endurance or ability to sustain contraction

define threshold

goal level of activity set by clinician

what is ionic activity measured in

microvolts (uV), range from 1-2000 uV

T/F: gain setting determines device sensitivity; higher gain setting, small change produce EMG signal

true

what are physiologic effects of EMG

response given to user based on myoelectric activity

feedback allows for volitional alteration in activity: activation or relaxation

what are the 3 neurophysiologic mechanisms

neuromuscular facilitation, inhibition, coordination

define neuromuscular facilitation

-combats arthrogenic muscle inhibition (AMI)

-increases muscle's ability to generate force: MVIC

-decreased AMI = increased ability to generate force

define neuromuscular inhibition "down training"

-decreased tone (fewer or smaller motor units)

-increased afferent inhibition of aberrant efferent signals

-uses: relaxation, postural training, reducing m. tone

define neuromuscular coordination

-improves timing and recruitment of m. activity, both m. timing and strength/force matter

-used with: musicians, athletes, and patients with central/peripheral neurological injury

what are clinical indications for EMG/Biofeedback

"hardcore muscles help patients control their chronic nerve gains"

-hemiplegia

-muscular strengthening

-headaches

-pelvic floor conditions

-temporomandibular disorders

-CVA

-Neck m. spasticity/whiplash

-Gait impairments

if a patient presents with a foot drop, what muscles will be targeted, what neurophysiological effects will be used, and what is the functional goal

anterior tib: facilitation

gastroc: inhibition

functional goal: improve gait

if a patient presets with shoulder hemiparesis, what muscles will be targeted, what effects will be used, and what is the functional goal

upper trap: facilitate

anterior deltoid: facilitate

functional goal: reduce shoulder subluxation

what are contraindications to EMG/Biofeedback

"PWAAB"

-Pregnancy (no intravaginal devices; not with preterm labor or high-risk pregnancy)

-Within 6 weeks of pelvic or rectal surgery

-Acute inflammation (fx, infection, DVT, post-op)

-Allergy to adhesives

-Bladder or vaginal infections: no intracavity

what are adverse effects

although relatively safe:

-skin reaction

-responses to cardiovascular and strengthening exercises

describe the application techniques

1. discuss goal of using biofeedback, contraindications, consent

2. skin prep: alcohol wipe, US gel on electrode

3. electrode placement: parallel with muscle fibers, may need to fix with tape; attach leads to unit

4. baseline and resting activity over 1-3 min time frame; then peak amplitude having them do max isometric contraction

5. set threshold level (at or above peak amplitude)

6. assess patient during tx, may need to adjust threshold or patient may not meet it because of fatigue

describe the process of muscle re-education

-start with maximal muscle contraction

-low sensitivity (patient can perform reps at 2/3 MVIC)

-6-10 sec isometric holds

-5-10 min per muscle group

what are the parameters for muscle relaxation

-requires high sensitivity

-electrodes start closer together

-10-15 min tx

**what must be documented following tx

-goal of tx

-tx area and electrode placement

-baseline amplitude

-peak amplitude

-threshold level

-net change in amplitude

-latency (rise/fall)

-duration of tx

-patient position

-activity during tx

-patient response to tx