Previous findings suggest that, in anosognosic patients, their illusory motor experience is based on a "normal" motor intention and planning for the paralyzed limbs. However, these studies involved proximal muscles (shoulder) that can be mediated by the ipsilateral (intact) cortex more than distal muscles (fingers). In the present study, we asked whether, in anosognosic patients, the spared motor intention for the paralyzed limb can go as far as to influence kinematic parameters of distal movements. Six hemiplegic patients (1 with and 5 without anosognosia) were required to reach and grasp with both hands targets of the same or different size, attached to a plinth. Maximum grip aperture of the right (intact) hand was recorded using an infrared motion capture system. All patients were evaluated with a specific battery for anosognosia and different neurpsychological test. In the patient affected by anosognosia for hemiplegia, the grip aperture of the healthy hand was influenced by the intended (but not executed) movement of the plegic hand when the patient was trying to reach to grasp targets of different size, F(2, 14) = 11.87, p < .001. Patients affected by hemiplegia (without anosognosia) didn't show any interference effect between the plegic and healthy hand even when they were asked to reach to grasp targets of different size. Our results confirm the hypothesis that a spared intention-programming system within the contralateral (damaged) cortex can go as far as to influence distal kinematic parameters of the healthy hand of patients affected by anosognosia for hemiplegia.

Objective: Expectations are known to be key determinants of placebo and nocebo phenomena. In previous studies, verbal suggestions to induce such expectations have mainly focused on the direction and magnitude of the effect, whereas little is known about the influence of temporal information. Methods: Using an experimental placebo and nocebo design, we investigated whether information about the expected onset of a treatment effect modulates the start and time course of analgesic and hyperalgesic responses. Healthy volunteers (n = 166) in three placebo and three nocebo groups were informed that the application of an (inert) cream would reduce (placebo groups) or amplify pain (nocebo groups) after 5, 15, or 30 minutes. Two control groups were also included (natural history and no expectations). Participants’ pain intensity rating of electrical stimuli administered before and 10, 20, and 35 minutes after cream application was obtained. Results: Mixed-method analysis of variance showed a significant interaction between group and time (F(12,262) = 18.172, p < .001, pη² = 0.454), suggesting that pain variations differed across time points and between groups. Post hoc comparisons revealed that the placebo and nocebo groups began to show a significantly larger change in perceived pain intensity than the no-expectancy control group at the expected time point (p < .05) but not earlier (p > .05). Once triggered, the analgesic effect remained constant over the course of the experiment, whereas the hyperalgesic effect increased over time. Conclusions: Our results indicate that temporal suggestions can shape expectancy-related treatment effects, which, if used systematically, could open up new ways to optimize treatment outcome.