The mapping of cortical activation by near-infrared spectroscopy might be a biomarker related to the severity of fibromyalgia symptoms

Abstract

The delta value of oxyhemoglobin (Δ-HbO) determined by functional near-infrared spectroscopy at prefrontal cortex (PFC) and motor cortex (MC) based on primary (25 °C) and secondary (5 °C) thermal stimuli presented a larger peak latency at left MC in fibromyalgia than in controls. The difference between HbO concentration 15 s after the thermal stimuli ending and HbO concentration before the thermal stimuli onset (Δ-HbO*) at left PFC increased 47.82% in fibromyalgia and 76.66% in controls. This value had satisfactory discriminatory properties to differentiate cortical activation in fibromyalgia versus controls. A receiver operator characteristics (ROC) analysis showed the Δ-HbO* cutoffs of − 0.175 at left PFC and − 0.205 at right PFC offer sensitivity and specificity of at least 80% in screening fibromyalgia from controls. In fibromyalgia, a ROC analysis showed that these cutoffs could discriminate those with higher disability due to pain and more severe central sensitization symptoms (CSS). The ROC with the best discriminatory profile was the CSS score with the Δ-HbO* at left PFC (area under the curve = 0.82, 95% confidence interval = 0.61–100). These results indicate that cortical activation based on Δ-HbO* at left PFC might be a sensitive marker to identify fibromyalgia subjects with more severe clinical symptoms.

Insula functional connectivity at EEG resting-state as a biomarker linked to pain processing and severity of clinical symptoms in fibromyalgia

“…Even though we do not have a clear hypothesis so far to accommodate all the differences between FM and HC found across the different frequency bands, it seems reasonable to derive some conclusions based on the neurophysiopathology of FM. Earlier studies that used other methods, like the EEG spectral density [16], the BOLD signal [13], and the transcranial magnetic stimulation (TMS) parameter [37], support this idea. Ultimately, this set of ndings aligns with the notion that cortical hypoactivation may be a marker of cortical dysfunction in FM.…”

Primary somatosensory cortex and periaqueductal gray functional connectivity as a marker of the dysfunction of the descending pain modulatory system in fibromyalgia

“…Considering this, it is possible that the left S1-PAG rs-FC results from an increased persistent excitatory input of pain signals between important antinociceptive locations, such as the brainstem. While several cortical regions have been proposed as possible sources of faulty pain inhibition in FM, the CSS scores reveal abnormal processes in the PFC and motor cortex [ 44 ].…”

Functional connectivity response to acute pain assessed by fNIRS is associated with BDNF genotype in fibromyalgia: an exploratory study

“…PFC dysfunction in chronic pain is associated with changes in neurotransmitters, gene expression, and neuroinflammation and with alterations in structure, activity, and connectivity during acute and chronic pain 15 . Also, left PFC activation assessed by fNIRS after thermal stimuli seem to be a sensitive marker of FM patients with more severe clinical symptoms 16 .…”