## 3 Results
### Data Synthesis  
#### 3.6.1 Photobiomodulation Therapy for Managing Pain Intensity in Fibromyalgia Patients  
The findings from the reviewed studies highlight the efficacy of PBMT in modulating pain perception and central sensitization in individuals with Fibromyalgia. Localized PBMT has demonstrated significant effectiveness in reducing hyperalgesia associated with tender points. In a placebo-controlled trial, [PERSON] et al. (2002) [51] applied a Class IIIb Ga-As laser (904 nm, 30 mW output) directly to tender points for 3 min per session over two weeks, resulting in a pain reduction from 3.09 to 1.27 (\(p<0.05\)). Similarly, [PERSON] et al. (2019) [47] investigated the effects of ten PBMT sessions in Fibromyalgia patients using a Class IIIb laser system, reporting a decrease in pain intensity from 6.9 to 3.5 (\(p<0.001\)), reinforcing its role in targeted pain modulation. Within localized applications, [PERSON] et al. (2023) [40] introduced a novel PBMT approach incorporating static magnetic fields (PBMT-sMF) via the FibrLuxTM system, which yielded the most significant pain reduction among the reviewed studies. The intervention, using 905 nm pulsed lasers, 850 nm infrared LEDs, and 630 nm red LEDs with a power output of 50 mW per laser diode, resulted in a VAS score decrease from 80.64 to 37.80 (\(p<0.0001\)). The treatment protocol involved direct skin contact at tender points for 120 s per site, delivering 60 J per region, administered three times per week, over three weeks. Additionally, this intervention significantly reduced the number of tender points, from 15.29 to 7.29 (\(p<0.0001\)), suggesting a substantial impact on central sensitization mechanisms. Beyond localized applications, whole-body PBMT has also been extensively studied for its systemic analgesic effects in Fibromyalgia syndrome. This modality involves the use of full-body light beds that emit red to near-infrared light (typically 660-850 nm) across the entire body, aiming to produce widespread biological effects through uniform tissue irradiation. In a single-arm feasibility study, [PERSON] et al. (2023) [36] evaluated the effects of 18 whole-body PBMT sessions over 6 weeks using the NovoTHOR(r) system (660-850 nm, total power output of 967 W), reporting a VAS pain reduction from 7.4 to 3.9 \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Outcome** & **1** & **2** & **3** & **4** & **5** & **6** & **7** & **Recommendation** \\ \hline Pain & 6 (n = 250) & Moderate & Low & Moderate & Moderate & Not serious & Moderate & Moderate in favor \\ \hline Quality of Life & 5 (n = 210) & Low & Moderate & Moderate & Moderate & Not serious & Moderate & Strong in favor \\ \hline Fatigue & 3 (n = 150) & Moderate & Moderate & Moderate & Moderate & Not serious & Moderate & Moderate in favor \\ \hline Tender Points & 4 (n = 180) & Moderate & Low & Moderate & Moderate & Not serious & Moderate & Moderate in favor \\ \hline Self-efficacy & 2 (n = 80) & Low & Low & Moderate & Moderate & Not serious & Moderate & Moderate in favor \\ \hline \hline \end{tabular} Summary of the findings and quality of the evidence assessed using the GRADE approach. The GRADE framework evaluates the certainty of evidence across four levels (high, moderate, low, and very low), based on factors such as the risk of bias, inconsistency, indirectness, imprecision, and publication bias: (1) number of studies (subjects), (2) risk of bias, (3) inconsistency, (4) indirectness, (5) imprecision, (6) publication bias, and (7) quality.  
\end{table} 
Table 2: Grade of recommendation (GRADE). (\(p\) < 0.001), with improvements maintained at a 24-week follow-up. Similarly, [PERSON] et al. (2023) [38] conducted a triple-blinded, randomized controlled trial using the same NovoTHOR(r) system, applying near-infrared and red-light therapy (660-850 nm, power density \(\sim\)40 mW/cm\({}^{2}\)) in 12 sessions, over 4 weeks.