Conclusions
Functional abnormalities in early somatosensory cortical processing (reduced N20m amplitude, cross-correlation value, and SI gamma responses) as well as impaired SI responses (increased non-response rate and P20m rate) can be clearly detected in patients with chronic MD using MEG. Single-trial neuromagnetic analysis of somatosensory function may therefore be useful for identifying central somatosensory disturbance and elucidating the relevant pathophysiological mechanisms even in chronic cases of MD.