Background: Pain is a common disabling non-motor symptom affecting patients with functional motor disorders (FMD). Objective: We aimed to explore ascending and descending nociceptive pathways with laser evoked potentials (LEPs) in FMD. Methods: We studied a "bottom-up and top-down" noxious paradigm applying a conditioned pain modulation (CPM) protocol and recorded N2/P2 amplitude in 21 FMD and 20 controls following stimulation of both right arm and leg at baseline (BS) (bottom-up), during heterotopic noxious conditioning stimulation (HNCS) with ice test (top-down) and post-HNCS. Results: We found a normal ascending pathway, but reduced CPM response (lower reduction of the N2/P2 amplitude) in FMD patients, by stimulating both upper and lower limbs. The N2/P2 amplitude ratio*100 (between the HNCS and BS) was significantly higher in patients with FMD than HC. Conclusions: Our results suggest that pain in FMD possibly reflects a descending pain inhibitory control impairment, therefore, providing a novel venue to explore the pathophysiology of pain in FMD. © 2024 International Parkinson and Movement Disorder Society.
Abnormalities of the descending inhibitory nociceptive pathway in functional motor disorders
Squintani, Giovanna;Geroin, Christian
;Pasquali, Alessia;Cavazzana, Eleonora;Segatti, Alessia;Lippolis, Marianna;Bonetto, Chiara;Antelmi, Elena;Tinazzi, Michele
2024-01-01
Abstract
Background: Pain is a common disabling non-motor symptom affecting patients with functional motor disorders (FMD). Objective: We aimed to explore ascending and descending nociceptive pathways with laser evoked potentials (LEPs) in FMD. Methods: We studied a "bottom-up and top-down" noxious paradigm applying a conditioned pain modulation (CPM) protocol and recorded N2/P2 amplitude in 21 FMD and 20 controls following stimulation of both right arm and leg at baseline (BS) (bottom-up), during heterotopic noxious conditioning stimulation (HNCS) with ice test (top-down) and post-HNCS. Results: We found a normal ascending pathway, but reduced CPM response (lower reduction of the N2/P2 amplitude) in FMD patients, by stimulating both upper and lower limbs. The N2/P2 amplitude ratio*100 (between the HNCS and BS) was significantly higher in patients with FMD than HC. Conclusions: Our results suggest that pain in FMD possibly reflects a descending pain inhibitory control impairment, therefore, providing a novel venue to explore the pathophysiology of pain in FMD. © 2024 International Parkinson and Movement Disorder Society.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.