Enhancing non-noxious perception: behavioural and neurophysiological correlates of a placebo-like manipulation.

Sensory perception can be influenced by cognitive functions like attention and expectation. An emblematic case of this is the placebo effect, where a reduction in pain perception can be obtained by inducing expectation of benefit following a treatment. The current study assessed the behavioural and brain activity correlates of a placebo procedure inducing an enhancement of non-noxious somatic sensation.

Muscular pain in Parkinson's disease and nociceptive processing assessed with CO2 laser-evoked potentials.

Muscular pain is the most frequent kind of nondystonic pain associated with Parkinson's disease (PD). It might be related not only to peripheral factors but also to an abnormal nociceptive input processing in the central nervous system. To test this hypothesis, we recorded CO(2) laser-evoked potentials (LEPs) in response to shoulder stimulation (skin over deltoid muscle) in 11 hemiparkinsonian PD patients complaining of muscular pain in the shoulder (ipsilateral to motor symptoms) and compared the results with those obtained in 12 pain-free PD patients with hemiparkinson and in 11 normal subjects.

Hyperalgesia and laser evoked potentials alterations in hemiparkinson: evidence for an abnormal nociceptive processing.

A number of patients with Parkinson's Disease (PD) complain of painful sensations that might be related not only to peripheral factors (muscle spasms, postural abnormalities) but also to an abnormal processing of nociceptive inputs in the Central Nervous System (CNS). To test this hypothesis, we recorded scalp CO(2) laser evoked potentials (LEPs) to foot skin stimulation in 11 pain-free treated PD patients affected by hemiparkinson (during the off state), in 6 pain-free drug-naïve hemiparkinsonian patients and in 11 healthy subjects. After each LEP recording, both patients and controls were asked to rate pain due to laser stimuli.

Abduction finger sign: a new sign to detect unilateral functional paralysis of the upper limb.

Objective of this study is testing a new sign to differentiate functional from organic paralysis of the arm. Thirty-six healthy subjects, ten patients with acute functional paralysis of one arm and eleven patients with acute organic paralysis of one arm were enrolled. The test consisted of abduction finger movements of one hand against resistance with a maximal sustained contraction to detect synkinetic abduction finger movements of the contralateral hand.