Use of Modalities in Upper Limb Management in Tetraplegia

Original Editor - Ewa Jaraczewska

Top Contributors - Ewa Jaraczewska, Jess Bell and Tarina van der Stockt  

Introduction

A wide range of therapeutic modalities addressing upper limb function in patients with tetraplegia is available in spinal cord injury rehabilitation. This article overviews the most commonly used modalities in treating clients with upper and lower tetraplegia.

Vibration

Muscle vibration is a technique that can potentially reduce muscle tone and spasticity in individuals with neurological disorders. A direct effect of muscle vibrations includes increased corticospinal excitability and inhibition of neuronal activity in the antagonistic muscle. Focal vibration as a modality in spinal cord injury facilitates a contraction of the agonist's muscle. Isometric contraction in triceps brachii were induced with the application of vibratory stimuli at 80 Hz on the muscle.

Three motor effects achieved through muscle vibration are as follows:

1. Sustained contraction of the vibrated muscle via tonic vibration reflex
2. Depression of the motor neurones innervating the antagonistic muscles via reciprocal inhibition or antagonistic inhibition
3. Suppression of the monosynaptic stretch reflexes of the vibrated muscle while being vibrated.

The sustained effect of vibration remains under investigation. According to Laessøe et al. , lower limb spasticity was reduced up to 3 hours following vibratory stimulation at 100 Hz.

Two different vibration frequencies can be chosen and applied directly to the muscle or tendon: high-frequency and low-frequency vibration.

High-Frequency Vibration

• Frequency of 100 - 200 Hz and
• Amplitude of 1 – 2 mA.
• Produce facilitation of muscle contraction through a tonic vibration reflex.
• The effect is brief after the application

Low-Frequency Vibration

• 5 -50 Hz
• Inhibitory effect on muscle through activating spindle secondary endings and the Golgi tendon organs.

General Precautions

• Heat generation at the point of the application when the high amplitude is used can cause skin damage
• Unstable health conditions (unstable spine, fractures)

Potential concerns related to use of vibration therapy

• Increased the risk of thrombosis
• Tissue damage from acute or severe oedema
• Increased cardiac issue
• Dislodgement of a thrombus
• Increased damage from peripheral vascular disease
• Effects on spinal stimulators
• Skin injury from friction

You can read more about self-applied vibration here.

Surface Stimulation

Two of the most commonly used forms of surface stimulation are:

• Transcutaneous Electrical Nerve Stimulation (TENS)
• Functional Electrical Stimulation(FES).

TENS

TENS is a "surface applied neuromodulation system that has been utilized in the treatment of various types of chronic pain, including noninvasive neuropathic pain relief." TENS stimulates sensory A-beta fibres in chronic pain management. As a result, pain signals transmitted via A-delta and C-nociceptive fibres are blocked. TENS enhances presynaptic inhibition in spasticity management following spinal cord injury and "induces short-term neuroplasticity by increasing the strength of reciprocal Ia inhibition" between antagonistic (flexors and extensors) muscles.

These points below summarise the mechanisms of TENS:

• It activates sensory nerves
• Sensory nerves activate inhibitory interneurons
• Spastic muscle activity is inhibited
• It may involve the stimulation of large diameter afferent fibres

Goals:

1. To reduce spasticity
2. To alleviate pain
3. To reduce muscle fatigue

Treatment Protocols Examples

Spasticity management:

• High frequency of 50–150 Hz
• Low-intensity (below motor threshold)

Neuropathic pain management:

• High frequency of 80 Hz
• Each session for 45 minutes
• Two sessions per day for eight weeks
• Adverse effects can be present: rash and local tingling sensation
• Possibility of relapse of neuropathic pain

FES

Functional Electrical Stimulation induces muscular contraction to complete a functional task via electrical stimuli applied to paralyzed nerves or muscles. The neurorehabilitation effect of FES supports the rewiring and regeneration of damaged synaptic connections.

The FES training can produce the following metabolic benefits:

• Increases in lean muscle mass
• Increases in capillary number
• Decreases in adipose tissue

Other benefits include lowering the blood glucose and insulin levels, improvement in muscle size, strength, and composition, improved fatigue resistance and oxidative capacities, proportional increases in fibre area and capillary number.

Goals:

1. To prevent upper limb muscle atrophy
2. To increase muscle strength
3. To increase endurance
4. To improve cardiovascular fitness

FES can be used to treat the upper limb in a person with tetraplegia to:

• Replace function (i.e., as an orthotic device)
• Retrain function (i.e., as a therapeutic device)

Replacing function

• A specific movement facilitation (neuroprosthesis)
• Neuroprosthesis consists of an electrical stimulator, stimulation-delivering electrodes, sensors for the user or automatic control of the stimulation, and an orthosis that provides additional assistance to perform the desired movement
  • Electrical stimulator generates the electrical discharges. It produces muscle contraction.
  • Electrodes connect the external circuitry and the tissue. They are transcutaneous or implantable.
  • Sensors provide the biofeedback for the neuroprosthesis. The maximum functionality of neuroprosthesis depends on sensors.
  • Orthosis provides assistance to perform the desired movement. It prevents muscle fatigue and helps patients conserve energy

The example of neuroprosthesis:

• IST-12 , a newer version of The Freehand system, designed to improve the ability to grasp and manipulate objects
• NESS H200
• Bionic Glove
• HandEstim Wireless Hand Stimulator
• MyndMove stimulator

Retraining function

• Short-term treatment modality
• The patient is expected to regain voluntary function
• Kapadia et al.described a protocol for transcutaneous FES to retrain reaching and grasping in individuals with spinal cord injury:
  • Upper extremity retraining program is designed based on the level and extent of the injury
  • The patient with upper tetraplegia will start with retraining proximal function followed by distal function training
  • The patient with lower tetraplegia will retrain distal function from the beginning
  • The patient with little to no voluntary movement at the wrist and fingers can perform simple tasks while being stimulated with the FES
  • The number of repetitions is based on each of the participant’s strength and endurance
  • 30–45 min out of 1-h session, the patient performs activities of daily living with FES
  • The following parameters are used: balanced, biphasic, current-regulated electrical pulse, pulse amplitude from 8 to 50 mA, pulse width 250 μs; and pulse frequency 40 Hz
  • During the session, the therapist guides the patient's hand to make the movement functional
  • Typical FES session is conducted for 45–60 min, 3–5 days a week, for 8–16 weeks, for a total of about 40 sessions

Resources

• Marquez-Chin C, Popovic MR. Functional electrical stimulation therapy for restoration of motor function after spinal cord injury and stroke: a review. Biomed Eng Online. 2020 May 24;19(1):34.
• Ragnarsson KT. Functional electrical stimulation after spinal cord injury: current use, therapeutic effects and future directions. Spinal Cord. 2008 Apr;46(4):255-74.