Abnormalities of the Descending Inhibitory Nociceptive Pathway in Functional Motor Disorders.

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.