Effect of Photobiomodulation Therapy in Patients With Hashimoto's Thyroiditis

Fatigue level in all patients was assessed by Fatigue Impact Scale (FIS) and Fatigue Severity Scale (FSS). The FIS is a forty-item scale indicating the consequences of fatigue on daily life such that it includes cognitive, physical and psychosocial subscales. The sum of the subscales ranges from 0 to 40 (physical and cognitive) and 0-80 (psychosocial); a higher score indicates a more severe impact of fatigue in daily life. FSS assesses the degree of physical fatigue over the past week and includes nine items. Patients indicate how much they agree or disagree with the statements for each item on a seven-point Likert scale. FSS scores ≥ 4.0 indicate clinically relevant fatigue.

General fatigue feeling of the individuals were evaluated by Visual Analogue Scale (VAS).Individuals were asked to mark their fatigue level on the scale. '0' means 'not tired at all' and '10'means 'very tired'.

The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality based on participants' sleep experiences in the past week. The PSQI is a self-administered questionnaire that has been proven to be a valid and reliable tool for measuring sleep quality and quantity. The PSQI consists of a total of seven components and nineteen questions, including subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication and daytime dysfunction. The sum of the seven dimensional components gives global scores ranging from 0 to 21, with higher scores indicating poorer sleep quality. Those having score above 5 are considered as to have "poor sleep quality" and those having score 5 and below are considered as to have "good sleep quality" .

Epworth Sleepiness Scale (ESS) was used to assess sleepiness. The ESS is a short, easy-to-administer questionnaire that subjectively assesses daytime sleepiness. The probability of falling asleep in the eight-day condition is determined by a scoring from 0 to 3 (0=no chance of napping, 1=slight chance of napping, 2=moderate chance of napping, 3=high chance of napping). The ESS score is the sum of eight item scores and ranges from 0 to 24. Higher ESS scores indicate greater daytime sleepiness.

The inventory consists of twenty-one items describing subjective, somatic or panic-related anxiety symptoms, respectively. Self-reports are based on a four-point Likert scale ranging from "not at all" to "severe" regarding the experience of this symptom in the past month. Higher scores indicate more severe levels of anxiety.

The Beck Depression Inventory (BDI) is a twenty-one-item self-assessment scale that measures symptoms of depression. Each item is scored from 0 to 3; the total score ranges from 0 to 63. It was stated that those having scores as seventeen and above were in the group at risk of depression. Depression levels: 0-9, minimal; 10-16, mild; 17-29, moderate; 30-63, severe.