Table 2.

Studies about laser evoked potentials (LEPs) in fibromyalgia (FM) and healthy controls (HC) published within the last 5 years. In bracket, disease duration in years is reported, when available

Authors	Methods	Subjects	Results	Significance
De Tommaso et al. (2017)	CO2 laser stimulation	50 FM (7.2 ± 6.21 y) and 30 HC	Reduced habituation of vertex LEPs	Finding supporting abnormal central elaboration of pain
Fasolino et al. (2020)	Nd:YAP laser stimulation	57 FM (7 ± 8.5 y)	Normal LEP parameters in patients with and without small-fiber pathology	Finding suggesting that small-fiber pathology has a negligible impact on somatosensory system function in fibromyalgia
Van Assche et al. (2020)	CO2 laser stimulation	92 FM 39 HC	Normal LEP parameters	Finding suggesting that small-fiber neuropathy is not a significant contributor to the pathophysiology of fibromyalgia
Vecchio et al. (2020)	CO2 laser stimulation	81 FM (10.69 ± 8.16 y)	Abnormal habituation index and correlation with reduced IENFD at the thigh	Finding suggesting central impairment of pain processing and association with mild proximal small-fiber pathology
Vecchio et al. (2022)	CO2 laser stimulation	37 FM (10.27 ± 7.17 y) (22 patients with proximal denervation, 18 with normal skin biopsy, and 7 with proximal and distal IENFD reduction	Reduced amplitude of the P2 component, not coherent with the site of denervation Decreased habituation of P2 prevailing in patients with reduced IENFD	Finding suggesting that LEP abnormalities are not the expression of small-fiber impairment in fibromyalgia

Sympathetic skin response — SSR — and autonomic assessment (heart rate variability-HRV)