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

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).

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.