Action Observation and Motor Imagery administered the day before surgery enhance functional recovery in patients after total hip arthroplasty: A randomized controlled trial.

OBJECTIVE: To investigate the effects of Action Observation and Motor Imagery administered the day before surgery on functional recovery in patients after total hip arthroplasty. DESIGN: Randomised controlled trial. SETTING: Humanitas Clinical and Research Center, Milan, Italy. PARTICIPANTS: Eighty inpatients with end-stage hip osteoarthritis undergoing total hip arthroplasty. INTERVENTIONS: All patients followed a standardized postoperative rehabilitation program. Experimental group (AO + MI) performed two 12-minute Action Observation and Motor Imagery sessions on the preoperative day, whereas control group underwent usual care consisting of education without any additional preoperative activity. OUTCOME MEASURES: A blinded physiotherapist assessed participants for functional mobility (Timed Up and Go - TUG) (primary outcome), maximum walking speed (10-Meter Walk Test - 10MWT), pain (Numeric Pain Rating Scale - NPRS) and fear of movement (Tampa Scale of Kinesiophobia - TSK) the day before and at four days after surgery. RESULTS: No between-group differences were found at baseline. Although TUG and 10MWT worsened in both groups (p < 0.001), better TUG was found for AO + MI group at four days (mean difference -5.8 s, 95% confidence interval from -11.3 to -0.3 s, p = 0.039). NPRS (p < 0.001) and TSK (p = 0.036 for AO + MI group, p = 0.003 for control group) improved after surgery without between-group differences. CONCLUSIONS: Patients undergoing Action Observation and Motor Imagery on the day before surgery showed less functional decline than control group in the first days after total hip arthroplasty. This intervention may contribute to a safer discharge with higher functional abilities in patients hospitalized for total hip arthroplasty.

Catching the imposter in the brain: The case of Capgras delusion.

Here we describe a rare case of Capgras delusion - a misidentification syndrome characterized by the belief that a person has been replaced by an imposter - in a patient without evident neurological or psychiatric symptoms. Intriguingly, delusional belief was selective for both person and modality, as the patient believed that his son - not his daughter or other relatives - was substituted with an imposter only while being in presence of him and looking at his face, but not when merely listening to his voice. A neuroanatomical reconstruction obtained integrating morphological and functional patient's neuroimaging data highlighted two main peculiarities: a compression of the rostral portion of right temporal lobe due to a large arachnoid cyst, and a bilaterally reduced metabolism of frontal areas. Autonomic data obtained from thermal infra-red camera and skin conductance recordings showed that a higher sympathetic activation was evoked by the observation of daughter's face, relative to the observation of the son's face as well as of not-familiar faces; conversely, daughter and son voices elicited a similar sympathetic activation, higher relative to not-familiar voices, indicating a modality-dependent dissociation consistent with the delusional behavior. Our case supports the "two-hit hypothesis" about Capgras delusion etiopathogenesis: here, the first hit is represented by the right-temporal lesion impairing the association between familiar faces and emotional values, the second one is the frontal bilateral hypometabolism favoring delusional behavior. The selective occurrence of "imposter" delusion for a particular subject and for a specific perceptual modality suggests the involvement of modality-specific interactions in the retrieval of affective properties during familiar people recognition.

Pathways for smiling, disgust and fear recognition in blindsight patients.

The aim of the present review is to discuss the localization of circuits that allow recognition of emotional facial expressions in blindsight patients. Because recognition of facial expressions is function of different centers, and their localization is not always clear, we decided to discuss here three emotional facial expression - smiling, disgust, and fear - whose anatomical localization in the pregenual sector of the anterior cingulate cortex (pACC), anterior insula (AI), and amygdala, respectively, is well established. We examined, then, the possible pathways that may convey affective visual information to these centers following lesions of V1. We concluded that the pathway leading to pACC, AI, and amygdala involves the deep layers of the superior colliculus, the medial pulvinar, and the superior temporal sulcus region. We suggest that this visual pathway provides an image of the observed affective faces, which, although deteriorated, is sufficient to determine some overt behavior, but not to provide conscious experience of the presented stimuli.

Impairment of actions chains in autism and its possible role in intention understanding.

Experiments in monkeys demonstrated that many parietal and premotor neurons coding a specific motor act (e.g., grasping) show a markedly different activation when this act is part of actions that have different goals (e.g., grasping for eating vs. grasping for placing). Many of these "action-constrained" neurons have mirror properties firing selectively to the observation of the initial motor act of the actions to which they belong motorically. By activating a specific action chain from its very outset, this mechanism allows the observers to have an internal copy of the whole action before its execution, thus enabling them to understand directly the agent's intention. Using electromyographic recordings, we show that a similar chained organization exists in typically developing children, whereas it is impaired in children with autism. We propose that, as a consequence of this functional impairment, high-functioning autistic children may understand the intentions of others cognitively but lack the mechanism for understanding them experientially.

The inferior parietal lobule: where action becomes perception.

The view defended in this article is that action and perception share the same neural substrate. To substantiate this view, the anatomical and functional organization of the inferior parietal lobule (IPL) is reviewed. In particular, it will be shown that many IPL neurons discharge selectively when the monkey executes a given motor act (e.g. grasping). Most interestingly, most of them fire only if the coded motor act is followed by a subsequent specific motor act (e.g. placing). Some of these action-constrained motor neurons have mirror properties and selectively discharge during the observation of motor acts when these are embedded in a given action (e.g. grasping for eating, but not grasping for placing). Thus, the activation of these IPL neurons allows the observer not only to recognize the observed motor act, but also to predict what will be the next motor act of the action, that is to understand the intentions of the action's agent. The finding that the same neurons that are active during the execution of specific motor acts also mediate the understanding of the 'what' and the 'why' of others' actions provides strong evidence for a common neural substrate for action and perception.

Parietal lobe: from action organization to intention understanding.

Inferior parietal lobule (IPL) neurons were studied when monkeys performed motor acts embedded in different actions and when they observed similar acts done by an experimenter. Most motor IPL neurons coding a specific act (e.g., grasping) showed markedly different activations when this act was part of different actions (e.g., for eating or for placing). Many motor IPL neurons also discharged during the observation of acts done by others. Most responded differentially when the same observed act was embedded in a specific action. These neurons fired during the observation of an act, before the beginning of the subsequent acts specifying the action. Thus, these neurons not only code the observed motor act but also allow the observer to understand the agent's intentions.