The Use of i/t Curve in Assessment of Phototherapy Effects

The Use of i/t Curve in Assessment of Effects of Biceps Brachii Phototherapy With PILER Light

Conventional electrodiagnostic examination is useful in daily physiotherapeutic practice. Nevertheless, the subjective assessment of muscle contraction and perceived current vibrations carries the risk of error and thus is a limitation of the method. Therefore, the use of the I/T curve coefficient was proposed in this study. This coefficient is the arithmetic mean of the electrical charge needed to trigger a sensory or motor reaction at different widths of the electrical pulse. PILER (Polychromatic Incoherent Low-Energy Radiation) light affects the sensory and motor excitability of the tissue. The resulting changes may depend on the colour of the filter used in the irradiations.

The study aimed to:

1. To evaluate changes in neuromuscular excitability occurring after PILER irradiation using filters of different colours.
2. To evaluate the usefulness of the I/T curve coefficient in neuromuscular excitation test.

60 healthy volunteers were assigned to one of four groups irradiated with: 1 - Piler light + red filter, 2 - Piler light + blue filter, 3 - Piler light without a filter, 4 - placebo.

Main Outcome Measures were plotting I/T curve coefficient for rectangular (■I/T coeff) and triangular (▲I/T coeff) pulses and the pressure pain threshold (PPT).

Study Overview

• Status: Completed
• Conditions: Nerve Disorders
• Intervention / Treatment: Radiation: Irradiations of the biceps brachii muscle with PILER light. The participants were randomized into 4 groups: group v - no filter/ group x - red filter/ group y - blue filter/ group z - placebo.

Detailed Description

Electrodiagnostic examination is a valuable addition to clinical trials and is useful in disorders of neuromuscular excitability.

The I/T curve is a non-invasive electrodiagnostic method for the quantitative assessment of neuromuscular excitation. Plotting it makes it possible to determine the rheobase (minimum stimulus amplitude to reach the stimulation threshold with a long pulse duration /1000 ms/) and chronaxie (minimum duration of a stimulus with an amplitude twice that of the rheobase needed to reach the stimulation threshold.

Traditional electrodiagnostic examination is popular among clinicians due to its availability, ease of administration and usefulness in physiotherapeutic practice. The subjective assessment of muscle contraction and perceived current vibrations carries the risk of error and thus is a limitation of the method. Therefore, use of the I/T curve coefficient was proposed in this study. This coefficient is the arithmetic mean of the electrical charge needed to trigger a sensory or motor reaction at different widths of the electrical pulse.

Polarized polychromatic incoherent low-energy radiation (PILER light) can affect the sensory and motor excitability of living tissue. The biological activity of light results from the energy of its ordered electromagnetic waves acting on living cells. No thermal effect is present, as the density of the energy transmitted to the tissues is low.PILER therapy often uses filters of different colours, each showing a slightly different effect on excitable tissue.

The research questions of this randomised experiment were:

1. Does PILER light affect sensory and motor excitation?
2. Does the electromagnetic wavelength of PILER light influence its effect?
3. Is the I/T curve coefficient a useful measure of sensory and motor excitation?

• Study Type: Interventional
• Enrollment (Actual): 60
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 23 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria included: informed consent, good tolerance of current pulses, completion of all phototherapy sessions, declaration of alcohol/drugs/smoking abstinence

The exclusion criteria were: acute inflammatory processes and fever, the presence of pigmented moles in the irradiated area, exposure to any other physical factors, a history of upper limb trauma, and upper limb overload.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Piler light + red filter; Group x: irradiation with a red filter (visible red radiation and infrared; 650-800 nm and 800-3900 nm, respectively) time of phototherapy treatment: 10 minutes for one session 10 irradiations to the biceps brachii muscle	Radiation: Irradiations of the biceps brachii muscle with PILER light. The participants were randomized into 4 groups: group v - no filter/ group x - red filter/ group y - blue filter/ group z - placebo.; Biceps brachii examination was carried out before (examination 1) and after (examination 2) a series of 10 PILER light treatments. It included a traditional electrodiagnostic examination and the assessment of the pressure pain threshold (PPT). The electrodiagnostic examination of the muscle was performed using the unipolar stimulation method from the direct motor point. The passive electrode (6 cm x 6 cm) was attached to the side of the distal part of the forearm, and the distal edge of the electrode was adjacent to the proximal edge of the ulnar styloid process. The examination was performed with a Multitronic MT3 electrotherapy apparatus set. PPT at the direct motor point was determined using an algometer (Algometer commander TM ITECH Medical Industries). A head with a rubber jacket with a surface area of 0.5 cm2 was used to cause pressure pain. Pressure was exerted until the participant reported pain, at which time the force (lbs) marked by the algometer was recorded.
Active Comparator: Piler light + blue filter; Group y: irradiation with a blue filter (blue radiation; 440-480 nm) time of phototherapy treatment: 10 minutes for one session 10 irradiations to the biceps brachii muscle	Radiation: Irradiations of the biceps brachii muscle with PILER light. The participants were randomized into 4 groups: group v - no filter/ group x - red filter/ group y - blue filter/ group z - placebo.; Biceps brachii examination was carried out before (examination 1) and after (examination 2) a series of 10 PILER light treatments. It included a traditional electrodiagnostic examination and the assessment of the pressure pain threshold (PPT). The electrodiagnostic examination of the muscle was performed using the unipolar stimulation method from the direct motor point. The passive electrode (6 cm x 6 cm) was attached to the side of the distal part of the forearm, and the distal edge of the electrode was adjacent to the proximal edge of the ulnar styloid process. The examination was performed with a Multitronic MT3 electrotherapy apparatus set. PPT at the direct motor point was determined using an algometer (Algometer commander TM ITECH Medical Industries). A head with a rubber jacket with a surface area of 0.5 cm2 was used to cause pressure pain. Pressure was exerted until the participant reported pain, at which time the force (lbs) marked by the algometer was recorded.
Active Comparator: Piler light without a filter; Group v: irradiation without a filter (white radiation in the entire spectrum and near-infrared radiation; 480-3400 nm) one session lasted 10 minutes 10 irradiations to the biceps brachii muscle	Radiation: Irradiations of the biceps brachii muscle with PILER light. The participants were randomized into 4 groups: group v - no filter/ group x - red filter/ group y - blue filter/ group z - placebo.; Biceps brachii examination was carried out before (examination 1) and after (examination 2) a series of 10 PILER light treatments. It included a traditional electrodiagnostic examination and the assessment of the pressure pain threshold (PPT). The electrodiagnostic examination of the muscle was performed using the unipolar stimulation method from the direct motor point. The passive electrode (6 cm x 6 cm) was attached to the side of the distal part of the forearm, and the distal edge of the electrode was adjacent to the proximal edge of the ulnar styloid process. The examination was performed with a Multitronic MT3 electrotherapy apparatus set. PPT at the direct motor point was determined using an algometer (Algometer commander TM ITECH Medical Industries). A head with a rubber jacket with a surface area of 0.5 cm2 was used to cause pressure pain. Pressure was exerted until the participant reported pain, at which time the force (lbs) marked by the algometer was recorded.
Placebo Comparator: placebo; Group z: placebo irradiation (without a filter, 3 min, distance: 100 cm). time of phototherapy treatment: 3 minutes for one session distance of 1meter 10 irradiations to the biceps brachii muscle	Radiation: Irradiations of the biceps brachii muscle with PILER light. The participants were randomized into 4 groups: group v - no filter/ group x - red filter/ group y - blue filter/ group z - placebo.; Biceps brachii examination was carried out before (examination 1) and after (examination 2) a series of 10 PILER light treatments. It included a traditional electrodiagnostic examination and the assessment of the pressure pain threshold (PPT). The electrodiagnostic examination of the muscle was performed using the unipolar stimulation method from the direct motor point. The passive electrode (6 cm x 6 cm) was attached to the side of the distal part of the forearm, and the distal edge of the electrode was adjacent to the proximal edge of the ulnar styloid process. The examination was performed with a Multitronic MT3 electrotherapy apparatus set. PPT at the direct motor point was determined using an algometer (Algometer commander TM ITECH Medical Industries). A head with a rubber jacket with a surface area of 0.5 cm2 was used to cause pressure pain. Pressure was exerted until the participant reported pain, at which time the force (lbs) marked by the algometer was recorded.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in the Pressure Pain Threshold (PPT)	Increase in PPT meant decrease in sensitivity to pressure in the muscle. Decrease in PPT meant increase in sensitivity to pressure in the muscle.	baseline measurement and 3 weeks after a series of 10 phototherapy treatments
Calculation of Sensory i/t Curve Coefficient for Rectangle (■I/T Coeff)	Based on the results of the electrodiagnostic test, sensory I/T curve was plotted for rectangular (■) pulses.The I/T curve coefficient was calculated as the mean value of the electric charge that caused the sensory response (notification by the subject of the sensation of current vibrations) according to the following equations:■I/T coeff = (q1+q2 +…+q13 )/13 , where pulse current × pulse duration = q in coulombs. Comparisons were made based on the changes in the ■I/T coeff, observed as a result of PILER irradiations.	baseline measurement and 3 weeks after a series of 10 phototherapy treatments
Calculation of Sensory I/T Curve Coefficient for Triangular (▲I/T Coeff) Pulses	Based on the results of the electrodiagnostic test, sensory I/T curve was plotted for triangular (▲I/T coeff) pulses.The I/T curve coefficient was calculated as the mean value of the electric charge that caused the sensory response (notification by the subject of the sensation of current vibrations) according to the following equations:▲I/T coeff = (q1+q2+… +q10) /10 , where pulse current × pulse duration = q in coulombs. Comparisons were made based on the changes in the ▲I/T coeff, observed as a result of PILER irradiations.	baseline measurement and 3 weeks after a series of 10 phototherapy treatments
Calculation of Motor i/t Curve Coefficient for Rectangle (■I/T Coeff)	Based on the results of the electrodiagnostic test, motor I/T curve was plotted for rectangular (■) pulses.The I/T curve coefficient was calculated as the mean value of the electric charge that caused the motor response (threshold muscle contraction) according to the following equations:■I/T coeff = (q1+q2 +…+q13 )/13 , where pulse current × pulse duration = q in coulombs. Comparisons were made based on the changes in the ■I/T coeff, observed as a result of PILER irradiations.	baseline measurement and 3 weeks after a series of 10 phototherapy treatments
Calculation of Motor I/T Curve Coefficient for Triangular (▲I/T Coeff) Pulses	Based on the results of the electrodiagnostic test, Motor I/T curve was plotted for triangular (▲I/T coeff) pulses.The I/T curve coefficient was calculated as the mean value of the electric charge that caused the motor response (threshold muscle contraction) according to the following equations:▲I/T coeff = (q1+q2+… +q10) /10 , where pulse current × pulse duration = q in coulombs. Comparisons were made based on the changes in the ▲I/T coeff, observed as a result of PILER irradiations.	baseline measurement and 3 weeks after a series of 10 phototherapy treatments

Collaborators and Investigators

• Sponsor: University of Rzeszow

Study record dates

Study Major Dates

• Study Start (Actual): February 1, 2016
• Primary Completion (Actual): July 1, 2019
• Study Completion (Actual): July 1, 2019

Study Registration Dates

• First Submitted: November 27, 2015
• First Submitted That Met QC Criteria: November 27, 2015
• First Posted (Estimate): December 1, 2015

Study Record Updates

• Last Update Posted (Actual): January 13, 2020
• Last Update Submitted That Met QC Criteria: December 28, 2019
• Last Verified: December 1, 2019

More Information

Terms related to this study

• Keywords: algometry; electrodiagnostics; i/t curve; neuromuscular excitation; PILER (Polychromatic Incoherent Low-Energy Radiation)
• Other Study ID Numbers: jz.i/t