Hypercapnia Reduces Perceived Heat Pain in Healthy Subjects.

Background: Danger signals modulate pain perception. Both amplification and attenuation of perceived pain are observed in healthy subjects exposed to danger signals, such as transient threats of an imminent electrical shock. However, exposure to danger signals in real life typically is not transient but constant over minutes to hours.

Healthy women show more experimentally induced central sensitization compared with men.

Women more often experience chronic pain conditions than men. Central sensitization (CS) is one key mechanism in chronic pain that can differ between the sexes. It is unknown whether CS processes are already more pronounced in healthy women than in men.

Are changes in nociceptive withdrawal reflex magnitude a viable central sensitization proxy? Implications of a replication attempt.

Objective: The nociceptive withdrawal reflex (NWR) has been proposed to read-out central sensitization (CS). Replicating a published study, it was assessed if the NWR magnitude reflects sensitization by painful heat. Additionally, NWR response rates were compared for two stimulation, the sural nerve at the lateral malleolus (SU) and the medial plantar nerve on the foot sole (MP), and three recording sites, biceps femoris (BF), rectus femoris (RF), and tibialis anterior (TA) muscles.

Limited prognostic value of pain duration in non-specific neck pain patients seeking chiropractic care.

Background: Pain chronicity is considered an important prognostic factor for outcome. Here, it was investigated whether pain duration influences outcome when only chronic patients (pain >3 months) are considered. Secondary aims were to determine, in patients of any pain duration, how much variance in outcome is explained by pain duration and whether pain duration truly predicts outcomes, that is out-of-sample prediction in independent data.