Biofeedback

Biofeedback

Objectives

  • Define Biofeedback: Understand what biofeedback is and its utilization for various disorders. (Outcome 3)

  • Use of Electrical Stimulation: Explain the application of electrical stimulation for patients with different conditions through a case study. (Outcome 4)

What is Biofeedback?

  • Biofeedback provides real-time information to the user about their physiological or biomechanical processes, fostering self-awareness and control over specific targeted processes.

  • Typically used to help individuals learn to self-regulate biological functions.

How Biofeedback Differs from Other Modalities

  • Biofeedback: Involves the user learning to control a targeted process using cognitive strategies, aiming to produce therapeutic or performance effects.

  • Other Modalities: These result in physiological effects due to the direct transfer of energy to the targeted tissue, without involving user control.

Two Types of Biofeedback

  1. Direct Biofeedback: Accurate external representation of internal biological processes.

    • Example: Heart rate monitor.

  2. Transformed Biofeedback: Processed information that represents internal biological processes.

    • Examples:

      • EMG: Represents electrical activity in muscle tissue.

      • EEG: Represents electrical activity in brain tissue.

EMG Biofeedback Overview

  • Focuses specifically on EMG biofeedback involving the conversion of intrinsic biological signals to extrinsic signals.

  • Surface Electrodes: Used to detect intrinsic electrical activity in muscle tissues; outputs can be auditory, visual, or haptic.

  • EMG biofeedback does not measure muscle contractility or tension directly but reflects electrical changes in the underlying tissue.

Surface Electrodes

  • Surface EMG does not directly measure muscle contractility but shows electrical changes in tissue.

  • Narrow Electrode Spacing: Captures data from superficial muscles.

  • Wider Electrode Spacing: Allows greater tissue sampling, though at a loss of specificity.

EMG Signal Processing

  • Steps involved in signal processing:

    1. Raw EMG Signal

    2. Amplified

    3. Rectified

    4. Smoothed

  • Processed signals are then relayed back to the user for feedback.

Key Parameters in EMG Biofeedback

  • Gain: Reflects the sensitivity of the device to various levels of ionic activity.

  • Peak Amplitude: The maximum EMG activity recorded during muscle contraction.

  • Contraction Latency: Duration between the initiation command and peak amplitude (approximately 0.5 seconds).

  • Return Latency: The period for electrical activity in muscle to revert to resting levels post-relaxation (approximately 1 second).

  • Hold Capacity: The time a muscle can sustain contraction as per the stability of EMG measured activity.

  • Intercontraction Baseline: The ionic activity level measured between muscle contractions.

  • Threshold: The electrical activity level necessary to generate a signal.

Threshold Settings

  • Threshold Setting: Goal level of myoelectrical activity determined by the therapist.

  • Above Threshold: Requires the patient to increase myoelectric activity to produce an EMG signal.

  • Below Threshold: Requires the patient to decrease myoelectric activity to generate an EMG signal.

Physiologic Effects of EMG Biofeedback

  • Neuromuscular Facilitation

  • Neuromuscular Inhibition

  • Neuromuscular Coordination

Neuromuscular Facilitation (Up Training)

  • Arthrogenic Muscle Inhibition (AMI):

    • Occurs due to injury/surgery, causing pain and swelling that inhibit muscle function, resulting in atrophy and dysfunction.

    • EMG biofeedback can counteract this by enhancing muscle’s force generation, increasing motor-unit recruitment, reducing recruitment latency, and enhancing neural excitability.

Neuromuscular Inhibition (Down Training)

  • For “Over-active” Muscles: Utilized for relaxation, postural training, and therapeutic exercises aimed at decreasing pain and muscle tone, while increasing range of motion (ROM) and functionality.

  • EMG facilitates this by reducing motor unit activation.

Neuromuscular Coordination

  • Definition: The improved timing and recruitment of muscle activity.

  • Common Applications:

    • Gait training.

    • Improvement of higher-level functional activities.

    • Utilized by athletes, musicians, and patients with neurologic injuries.

Clinical Indications for EMG Biofeedback

  • Indications Include:

    • Hemiplegia

    • Quadriceps strengthening

    • Headaches

    • Pelvic floor disorders

    • Chronic pain conditions

    • Temporomandibular joint (TMJ) disorders

EMG Application for Hemiplegia Post-Stroke

  • Clinical Indications:

    • Primary Target Muscle:

    • Footdrop: Anterior tibialis and gastrocnemius muscles for gait improvement.

    • Shoulder hemiparesis: Upper trapezius and anterior deltoid for reducing shoulder subluxation.

    • Hand hemiparesis: Wrist/finger flexors and extensors to improve grasp.

EMG for Quadriceps Strengthening

  • Addressing knee pain related to quadriceps dysfunction is crucial for recovery.

  • Evidence-Based Practice: Shows EMG biofeedback is effective for pain and strength improvement post-surgery but less so for chronic issues.

EMG for Headaches

  • EMG biofeedback is well-established for managing migraine and tension-type headaches.

  • Focus is on reducing muscle tension and improving patient self-efficacy.

EMG for Pelvic Floor Disorders

  • Effective for various pelvic disorders including:

    • Urinary Incontinence: EMG is recommended for managing stress urinary incontinence, often combined with Kegel exercises.

    • Fecal Incontinence and Constipation: Inhibition and relaxation strategies applied.

    • Dyspareunia: Addressed by inhibiting muscle activation.

  • Treatment requires specialized training.

EMG for Temporomandibular Disorders (TMD)

  • Conditions affecting the TMJ include pain and limited movement.

  • Evidence suggests that combining EMG biofeedback with relaxation training is beneficial.

EMG for Chronic Pain Conditions

  • Investigated for musculoskeletal pain; benefits observed but not significantly better than other treatments.

  • Fibromyalgia Treatment: EMG biofeedback presents some short-term benefits for pain relief.

General Physiologic Effects with EMG for Pain

  • Facilitation: Enhancing muscle activation can mitigate stress on painful areas, restoring movement patterns and joint stability.

    • Example: Increases muscle activation.

  • Inhibition: Lowering muscle tone may improve circulation to painful areas, alleviating noxious stimuli.

Contraindications

  1. Acute inflammatory conditions: Certain circumstances can exacerbate pain or interfere with healing:

    • Certain surgical conditions.

    • Acute fractures.

    • Inflamed tissues or infections.

    • Within 72 hours of an injury.

    • Post-surgery within the first 6 weeks without specific physician guidance.

  2. Pregnancy: No intravaginal devices due to infection risk; avoid during high-risk pregnancies and initial postpartum recovery.

  3. Infection: No use of EMG for pelvic floor re-education in presence of infections.

  4. Allergies: To electrode materials or contact substances.

  5. Sensitive Areas: Avoid application in sensitive regions such as over the eyes.

Precautions

  • Diminished Skin Sensation: Limits effectiveness; consider electrode placement adjustments.

  • Patients with Epilepsy: May react negatively to visual feedbacks; monitor closely.

Adverse Effects of EMG

  • Excessive Strengthening: Risks include dyspnea, fatigue, cardiac stress, and delayed onset muscle soreness (DOMS).

  • Skin Reactions: Skin irritation can arise from electrode use.

Application Technique

  • Pretreatment Assessment:

    • Assess skin sensation, and impairments (pain, ROM, palpation, strength) to determine electrode placement and goals.

Application Steps

  1. Instruct Patient: Discuss the treatment goal and possible adverse responses.

  2. Skin Preparation: Clean thoroughly.

  3. Electrode Placement: Attach and activate for feedback.

  4. Facilitation Protocol:

    • Establish resting EMG activity baseline over 1-3 minutes.

    • Record peak amplitude from maximum voluntary isometric contraction (MVIC).

    • Set thresholds slightly above peak amplitude for facilitation goals.

    • Instruct isometric contraction maintenance during treatment.

    • Monitor and adjust as necessary during the session.

    • Remove electrodes and machine post-treatment.

Electrode Application Skills

  • Clean Skin: Ensure effective conductivity.

  • Electrode Orientation: Parallel to muscle fibers to enhance signal quality.

  • Signal Quality Influencers: Consider adipose layer thickness, electronic interference, and artifacts from cardiac and respiratory tissue activity.

Post Treatment Assessment

  • Evaluate for improvements; inspect skin conditions.

  • Reassess pain, ROM, strength, and functional outcomes.

  • Home Instructions: Guide on EMG usage and exercises.

Documentation Required

  • Document treatment goals, specific muscle area, electrode placements, threshold levels, baseline am, gain, peak amplitude, amplitude change, latencies, treatment duration, exercise/activity parameters, patient positioning, and responses to treatment.