Measuring expectation of pain: Contingent negative variation in placebo and nocebo effects

The Power of Expectation – Understanding the Placebo and Nocebo Phenomenon

Although placebo pills are supposed to have no pharmacological activity, people taking placebo pills describe a variety of positive (i.e., placebo phenomenon) and negative (i.e., nocebo phenomenon) reactions. This has major clinical implications. Placebo reactions account for a substantial part of improvement when treating patients with hypertension, mental disorders, and even after surgical pr...

Contingent negative variation response in chronic pain patients.

The present study assesses central processing of subjective appraisal, expectancy, orientation and reaction time as indexed by Contingent Negative variation (CNV) response in chronic pain patients. Waves N1, P3 and CNV were recorded during a CNV paradigm in a simple reaction time task with a constant interstimulus interval (ISI) of 1 sec. CNV was measured from CZ x FZ in controls and chronic pa...

Contingent negative variation in epilepsy

The contingent negative variation (CNV) is a long-latency event-related potential elicited by paired or associated stimuli. We recorded contingent negative variation in 50 patients with complex partial and secondarily generalized seizures and in 20 neurologically and psychiatrically normal unmedicated controls. CNV was recorded from Fz, Cz, and Pz. A 2000 Hz tone was followed after 1.5 s by 100...

Nonconscious activation of placebo and nocebo pain responses.

The dominant theories of human placebo effects rely on a notion that consciously perceptible cues, such as verbal information or distinct stimuli in classical conditioning, provide signals that activate placebo effects. However, growing evidence suggest that behavior can be triggered by stimuli presented outside of conscious awareness. Here, we performed two experiments in which the responses t...

Pain, placebo, and nocebo: epistemic, ethical, and practical issues.