Decreased prefrontal brain activation during verbal fluency task in patients with somatoform pain disorder: An exploratory multi-channel near-infrared spectroscopy study.

BACKGROUND

Pain is a common phenomenon. Patients with somatoform pain disorder (SPD) suffer from lasting chronic pain which may cause cognitive impairment. The dysfunction of prefrontal cortex (PFC) may be involved in pain-induced cognition impairment, which is the most important part in regulating of cognitive function. Multi-channel near-infrared spectroscopy (NIRS) is a noninvasive and low-cost functional neuroimaging technique being used to detect the prefrontal cortex activation during cognitive tasks to demonstrate the relationship between PFC dysfunction and cognition impairment in SPD patients.

METHODS

24 patients with SPD and 24 age-, gender- and education level-matched healthy controls were examined by NIRS of the relative concentration of oxygenated hemoglobin (oxy-Hb) in PFC during verbal fluency task (VFT). All data analysis procedures were accomplished under MATLAB, SPM and SPM-fNIRS which is an SPM12-based software for fNIRS analysis.

RESULTS

1. The number of words generated during the VFT tasks in SPD patients were fewer than healthy controls. 2. The activated areas in SPD patients were smaller than healthy controls. 3. The average activation strength of [oxy-Hb] in SPD patients was much lower than healthy controls. 4. The difference of activation areas between left and right lobe were particularly obvious in SPD patients.

CONCLUSION

There are evidences suggested that the markedly dysfunction in PFC especially bilateral dorsolateral prefrontal cortex (DLPFC) areas may be involved in the cognitive deficiency in patients with SPD.