Sensory room: Naturalistic assessment of auditory and visual perception in developing children.

INTRODUCTION: Hearing is essential for language acquisition and understanding the environment. Understanding how children react to auditory and visual information is essential for appropriate management in case of hearing loss. Objective and subjective assessments can diagnose hearing loss, but do not measure natural perception in children. We developed a "sensory room" for complementary assessment of children's perceptions so as to assess behavioral responses to meaningful natural sounds and visual stimuli in an ecologic environment suited to children. MATERIAL AND METHODS: Sixteen normal-hearing children and 10 with congenital hearing loss before cochlear implantation, aged 13 to 32months, were included in this feasibility study. They perceived 18 environmental sounds and 9 visual stimuli, and their behavioral responses were coded accordingly as: stopping, looking, moving, pointing, language or emotional reactions. RESULT: All children completed the task, demonstrating its feasibility in children. Percentage responses to auditory versus visual stimuli did not differ in normal-hearing children; those with congenital hearing loss responded like normal-hearing children to visual stimuli, but did not react to auditory stimuli. Progression in normal-hearing children's behavioral responses corresponded to cognitive and linguistic development according to age. CONCLUSION: The "sensory room" quantified children's responses to various auditory and visual stimuli, providing clinicians with measurable insight into the children's sensory perception and processing.

The time windows of the sense of agency.

The sense of agency depends on some internal cues that derive from action control, as well as external cues like contextual information and prior information (degree of contingency between an action and is effect). We assessed whether external agency cues are combined with internal agency cues to affect the sense of agency. In two experiments participants performed a movement (button press) that elicited, after a varying delay, an effect (ball appearing on a screen), and reported their sense of agency over the effect (full, partial or no-agency) while internal cues (premotor information) and external cues (contextual and prior information) were manipulated. We assessed the effect of agency cues on the delays at which the sense of agency varied. The delays were increased with premotor signals but were decreased with contextual information. These findings favour a model of integration of internal and external agency cues over time.

[Sense of body in schizophrenia]. / Sens du corps dans la schizophrénie.

First-rank symptoms of schizophrenia have been related to an impaired sense of agency (the sense of causing and controlling an action). The sense of agency is considered as one of the two components of self-recognition, the other component being the sense of body (awareness of one's body). The present study aimed at evaluating whether first-rank symptoms can be considered as a general impairment in self-recognition that will also concern the sense of body. A group of schizophrenic patients with first-rank symptoms, a group of schizophrenic patients without first-rank symptoms and a group of normal subjects were compared in a self-recognition task where they first had to execute hand movements simultaneously with the experimenter and subsequently to indicate the position either of their own or the experimenter's hand. The visualized locations of the hands could rotate by 0 degrees , 90 degrees , -90 degrees or 180 degrees from their real locations. This rotation allowed us to induce a distorted sense of body since there was a visual discontinuity between the patient's hand and the rest of his/her body. If patients present a perturbed sense of body we would expect a greater impairment in discriminating between their own hand and the experimenter's hand as the rotation values increased. This preliminary study shows that patients with first-rank symptoms are more impaired than normal subjects in distinguishing between their own hands and the experimenter's hands when the visualization of the locations of their hands were rotated respective to their real locations. However, both group of patients performed equally, thus showing that sense of body impairment is not specific to first-rank symptoms. These symptoms, compared to other symptoms of schizophrenia do not reflect general self-recognition impairment but rather a specific impairment of the sense of agency.

Cancelling discrete and stopping ongoing rhythmic movements: Do they involve the same process of motor inhibition?

Motor inhibition is considered to be an important process of executive control and to be implicated in numerous activities in order to cancel prepared actions and, supposedly, to suppress ongoing ones. Usually, it is evaluated using a "stop-signal task" in which participants have to inhibit prepared discrete movements. However, it is unknown whether other movement types involve the same inhibition process. We therefore investigated whether the inhibition process for discrete movements is involved in stopping ongoing rhythmic movements as well. Twenty healthy adults performed two counterbalanced tasks. The first task was used to estimate the stop-signal reaction time (SSRTd) needed to inhibit prepared discrete key-pressing movements. In the second task, participants drew graphic patterns on a tablet and had to stop the movement when a stop-signal occurred. We calculated the rhythmic stop signal-reaction time as the time needed to initiate stopping such ongoing rhythmic movement (SSRTr) and the same latency relative to the period of the rhythmic movement (relSSRTr). We measured these delays under different movement frequencies and motor coordination conditions and further investigated whether they varied as a function of several parameters of the rhythmic movements (speed, mean and variance of the relative phase, and movement phase at several time events). We found no correlation between inhibition measures in the two tasks. In contrast, generalized linear models showed a moderate yet significant influence of the motion parameters on the inhibition of ongoing rhythmic movements. We therefore conclude that the motor inhibition processes involved in cancelling prepared discrete movements and stopping ongoing rhythmic movements are dissimilar.

Effect of distorted visual feedback on the sense of agency.

It has been hypothesized that an internal model is involved in controlling and recognizing one's own actions (action attribution). This results from a comparison process between the predicted sensory feedback of the action and its real sensory consequences. The aim of the present study is to distinguish the respective importance of two action parameters (time and direction) on such an attribution judgment. We used a device that allows introduction of discordance between the movements actually performed and the sensory feedback displayed on a computer screen. Participants were asked to judge whether they were viewing 1) their own movements, 2) their own movements modified (spatially or temporally displaced), or 3) those of another agent (i.e, the experimenter). In fact, in all conditions they were only shown their own movements either unaltered or modified by varying amounts in space or time. Movements were only attributed to another agent when there was a high spatial discordance between participants' hand movements and sensory feedback. This study is the first to show that the direction of movements is a cardinal feature in action attribution, whereas temporal properties of movements play a less important role.

Defective recognition of one's own actions in patients with schizophrenia.

OBJECTIVE: The possibility that delusions of influence could be related to abnormal recognition of one's own actions was investigated in persons with schizophrenia. METHOD: Schizophrenic patients with (N=6) and without (N=18) delusions of influence were compared with normal subjects (N=29) on an action recognition task. The image of a virtual right hand holding a joystick was presented to the subjects through a mirror so that the image was superimposed on their real hand holding a real joystick. Subjects executed discrete movements in different directions. Angular biases and temporal delays were randomly introduced in some trials, such that the movement of the virtual hand departed from the movement executed by the subjects. After each trial, subjects were asked whether the movement they saw was their own. RESULTS: Compared with normal subjects, both patient groups made significantly more recognition errors in trials with temporal delays. In trials with angular biases, the error rate of patients with delusions of influence significantly differed from that of comparison subjects and from that of patients without delusions of influence. CONCLUSIONS: The findings support the hypothesis that delusions of influence are associated with a quantifiable difficulty in correct self-attribution of actions. This difficulty may be related to a specific impairment of a neural action attribution system.

Advanced colorectal cancer treated with combined 5-fluorouracil and folinic acid: the experience within a surgical department.

Thirty-seven patients with advanced colorectal cancer were treated with fluorouracil (5-FU) and folinic acid (FA) (Jan 1990-Dec 1992). Clinical assessment and administration of chemotherapy was incorporated as part of the daily work load of a busy general surgical unit. Records were available for all 37 patients and showed that 13 patients (Treatment failures, Group B) failed to receive more than 3 monthly cycles of treatment, while the remaining 24 received 6 or greater cycles (Treatment completed, Group A). There was no survival advantage demonstrated for the complete study cohort (n = 37) when compared to an historical group (n = 1038) of untreated patients. Median survival in Group A (14.2 months) was significantly greater (chi-squared, P < 0.0001) than survival in Group B (6.7 months). Toxicity was common with 43% experiencing mouth ulcers or stomatitis (13% severe). Three per cent had dose-limiting diarrhoea and myelotoxicity was minimal. There were six partial responses and 16 patients had no change in their disease status while on treatment. Current regimen of 5-FU/FA are well-tolerated with low toxicity but show no survival advantage for advanced colorectal cancer. However, these regimens may be administered within the confines of general surgical practice.

Experiencing oneself vs another person as being the cause of an action: the neural correlates of the experience of agency.

The present study is aimed at identifying the neural correlates of two kinds of attribution: experiencing oneself as the cause of an action (the sense of agency) or experiencing another person as being the cause of that action. The experimental conditions were chosen so that they differed only in their requirement to attribute an action to another person or to oneself. The same motor task and the same visual stimuli were used in the experimental conditions. Subjects used a joystick to drive a circle along a T-shaped path. They were told that the circle would be driven either by themselves or by the experimenter. In the former case subjects were requested to drive the circle, to be aware that they drove the circle, and thus to mentally attribute the action seen on the screen to themselves. In the latter case they were also requested to perform the task, but they were aware that action seen on the screen was driven by the experimenter. In accord with previous studies, the results showed that being aware of causing an action was associated with activation in the anterior insula, whereas being aware of not causing the action and attributing it to another person was associated with activation in the inferior parietal cortex. These two regions are involved in the perception of complex representations of the self and of its interactions with the external world. We suggest that the anterior insula is concerned with the integration of all the concordant multimodal sensory signals associated with voluntary movements. The inferior parietal cortex, in contrast, represents movements in an allocentric coding system that can be applied to the actions of others as well as the self.

The role of proprioception in action recognition.

This study aimed at evaluating the role of proprioception in the process of matching the final position of one's limbs with an intentional movement. Two experiments were realised with the same paradigm of conscious recognition of one's own limb position from a distorted position. In the first experiment, 22 healthy subjects performed the task in an active and in a passive condition. In the latter condition, proprioception was the only available information since the central signals related to the motor command were likely to be absent. The second experiment was realised with a deafferented patient who suffers from a complete haptic deafferentation, including loss of proprioception. The results first argue in favour of a dominant role of proprioception in action recognition, but they also stress the possible role of central signals. The process of matching the final position of one's limbs with an intended movement and thus of action recognition would be achieved through a comparison process between the predicted sensory consequences of the action, which are stored in its internal model, and the actual sensory consequences of that action.

A role for the ventral visual stream in reporting movements.

In this experiment we contrast the neural activity associated with reporting a stimulus attribute with the activity that occurs when the same stimulus attribute is used to guide behavior. Reporting the characteristics of a stimulus differs from simply tracking that stimulus since reporting requires that a stimulus is explicitly recognized and associated with an arbitrary response. In one condition the subject used his right finger to follow a square that moved randomly on a screen. In a second condition he had to indicate changes in the direction of the square's movements by touching one of two report buttons with his right finger. Two other conditions were added to control for the differences in the form of movement between the two primary conditions. When the reporting condition was contrasted with the tracking condition (controlling for the differences in the form of movement), areas in the ventral visual system (the left ventral prefrontal cortex and the left inferior temporal cortex) were activated. This study shows that contrasting a manual task which involves a report with a manual task which does not activates the ventral visual system. However, the observation of additional activity in other areas suggests that, while activity in the ventral stream is necessary for reporting, it is not sufficient.

Glucose infusion rates from various complex carbohydrates estimated from two models.

Due to the importance of diet in the management of noninsulin dependent diabetes, we are interested in constructing a model to study the glycemic response to different foods in normal and diabetic subjects. In this study, serum glucose and insulin values from individual normal subjects (Diab. 26, 1178) following the ingestion of different foods (corn, rice, bread, potato) high in complex carbohydrate were analyzed to determine glucose infusion rates (J) into the blood from the gut as a function of time following the ingestion of the food item. A Modular Modeling Program was designed to allow selection of data, curve fit, model, and tuning of parameters. The two models used were from Ackerman et al (Phys. Med. Biol. 9, 203) and the minimal model (VI) from Bergman and Cobelli (Fed. Proc. 39,110). The models were modified so that glucose and insulin values were used as input and J was the output. There was a good correspondence between the shape of the J curves predicted by the two models. While the J curves resembled serum glucose curves, they generally reached a peak earlier and declined more rapidly. Two peaks occurred in the J curves for bread, corn and rice. The second peaks may correspond to a delay in the release of glucose during digestion. The resulting infusion rate characterization of these foodstuffs maybe useful for modeling responses in diabetic patients with normal gut function but with impaired peripheral glucose utilization and in detecting abnormal gut function.

Modulating the experience of agency: a positron emission tomography study.

This study investigated agency, the feeling of being causally involved in an action. This is the feeling that leads us to attribute an action to ourselves rather than to another person. We were interested in the effects of experimentally modulating this experience on brain areas known to be involved in action recognition and self-recognition. We used a device that allowed us to modify the subject's degree of control of the movements of a virtual hand presented on a screen. Four main conditions were used: (1) a condition where the subject had a full control of the movements of the virtual hand, (2) a condition where the movements of the virtual hand appeared rotated by 25 degrees with respect to the movements made by the subject, (3) a condition where the movements of the virtual hand appeared rotated by 50 degrees, and (4) a condition where the movements of the virtual hand were produced by another person and did not correspond to the subject's movements. The activity of two main brain areas appeared to be modulated by the degree of discrepancy between the movement executed and the movement seen on the screen. In the inferior part of the parietal lobe, specifically on the right side, the less the subject felt in control of the movements of the virtual hand, the higher the level of activation. A reverse covariation was observed in the insula. These results demonstrate that the level of activity of specific brain areas maps onto the experience of causing or controlling an action. The implication of these results for understanding pathological conditions is discussed.

[Chylous effusion and surgical treatment of diaphragmatic hernia in 2 newborn infants]. / Epanchement chyleux après cure chirurgicale d'une hernie diaphragmatique chez 2 nouveau-nés.

BACKGROUND. Post-operative chylous effusion is rare in infants. It may result from venous thrombosis, thoracic duct injury or lymphatic vessel obstruction. This paper describes 2 cases of diaphragm hernia with post-operative chylous effusion. CASE REPORTS Case 1: A newborn developed chylous ascites two weeks after repair of a left posterolateral diaphragm hernia. Abdominal paracentesis showed milky fluid containing numerous lymphocytes (98%). Ascites was rapidly reduced by feeding with medium-chain triglyceride-rich (MCT) formula. Case 2: A chylothorax was seen 7 days after surgery to repair a left posterolateral diaphragm hernia. Thoracocentesis showed serous fluid containing numerous lymphocytes (93%). The chylothorax was resolved after two thoracocenteses, parenteral nutrition and feeding with MCT formula. CONCLUSION. These cases are the third report of chylothorax and the second report of chylous ascites after surgical repair of a diaphragm hernia. The exact cause of the chylous effusion is not clear.