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

Study Overview
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Brief Summary
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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: To evaluate changes in neuromuscular excitability occurring after PILER irradiation using filters of different colours. 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).

Detailed Description
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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: Does PILER light affect sensory and motor excitation? Does the electromagnetic wavelength of PILER light influence its effect? Is the I/T curve coefficient a useful measure of sensory and motor excitation?

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

Conditions
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Nerve Disorders

Intervention / Treatment
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* 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.


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 23 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Piler light + red filter<br>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.<br>* 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.<br>|
| Active Comparator: Piler light + blue filter<br>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.<br>* 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.<br>|
| Active Comparator: Piler light without a filter<br>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.<br>* 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.<br>|
| Placebo Comparator: placebo<br>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.<br>* 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.<br>|

What is the study measuring?
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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 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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electrodiagnostics, i/t curve, neuromuscular excitation, PILER (Polychromatic Incoherent Low-Energy Radiation), algometry