Analysis of methods to determine the latency of online movement adjustments

When studying online movement adjustments, one of the interesting parameters is their latency. We set out to compare three different methods of determining the latency: the threshold, confidence interval, and extrapolation methods. We simulated sets of movements with different movement times and amplitudes of movement adjustments, all with the same known latency. We applied the three different methods in order to determine when the position, velocity, and acceleration of the adjusted movements started to deviate from the values for unperturbed movements. We did so both for averaged data and for the data of individual trials. We evaluated the methods on the basis of their accuracy and precision, and according to whether the latency was influenced by the intensity of the movement adjustment. The extrapolation method applied to average acceleration data gave the most reliable estimates of latency, according to these criteria.     

The Jerusalem TeleRehabilitation System, a new low-cost, haptic rehabilitation approach.

Survivors of brain injury or stroke can improve movement ability with intensive, supervised practice. Since the hours of supervised therapy with a physical or occupational therapist are limited, telerehabilitation will enable patients to greatly expand the hours that they practice therapeutic exercises. The Jerusalem TeleRehabilitation System (JTRS) consists of patient and therapist systems plus a central server and database connected via the internet. The system can work in two modes: (1) a cooperative mode in which the therapist and patient are online at the same time, and (2) a stand-alone mode in which the patient uses the system on his own. In both cases, the system will monitor the status and progress of the patient and various parameters of his movement abilities, and prepare reports for the patient and for the therapist. From the clinic, the therapist will be able to change the screen seen by the patient and change the level and types of tasks, as needed. Compared to existing systems, our system will have the following advantages: (1) inexpensive and easy to use; (2) remote monitoring and control of the patient's computer by the therapist in the clinic; (3) more detailed analysis of patient status and progress; (4) a "smart" system which self-adapts to the patient's capabilities in real time, increasing or decreasing the difficulty of the exercise as needed; and (5) a central, international database which, by gathering data on many patients over time, will provide the basis for "smart" therapy and will also facilitate coordinated multicenter research studies.     

Movement in the ipsilesional hand is segmented following unilateral brain damage

Unilateral stroke results in hemiplegia or hemiparesis of the contralateral side of the body. The ipsilateral side of the body, the so-called "good" side, is often assumed to have no deficit. However, there is increasing evidence that the function of the unaffected limbs, especially the upper extremities, is different from that of normal age-matched controls. In the present study, we examined the motor control of both hands of chronic stroke subjects, 6 with left hemisphere brain damage (LHBD) and 5 with right hemisphere brain damage (RHBD). The control group consisted of 5 normal age-matched subjects. The task of the subject was to move a handle by flexing his/her fingers until the target position was reached. The target position was set as 33% of the range of each subject. No time constraints were imposed. The movements of the normal subjects were basically smooth, with few hesitations. In contrast to this, the movements of both hands in the two stroke groups were segmented and characterized by multiple starts and stops. As compared to normals, the time to reach the target, the number of pauses during the movement, and the percent of time spent in pauses, were significantly greater for both hands of the LHBD group. In the RHBD group, the percent of time spent in pauses was significantly greater than the control group for the ipsilesional hand. The increased segmentation seen in the movements of the ipsilesional, as well as the contralesional. hands of the hemiplegic subjects suggests that the motor deficits in stroke patients may be due to a global inability to correctly plan and carry out movements.     

Perceived target displacement as a function of field movement and asymmetry

In two experiments induced movement of an object was produced to demonstrate that movement of the background influences the perceived localization of the object in space. The Roelofs (asymmetry) effect could be used to explain only part of the shift in localization in Experiment1. The asymmetry effect was excluded from Experiment2 by the procedure employed. It was concluded that the Roelofs effect is a sufficient, but not necessary, condition for the effects of induced movement to occur, and that relative displacement of the target and background plays an important part in the illusion. Furthermore, it was shown that the effects of induced movement can occur even when the border of the background remains stationary.     

The Persuasive Effects of Emotive Visual Imagery: Superficial Manipulation or the Product of Passionate Reason?

This study reevaluates the persuasive impact of emotional visual appeals within politics and examines two different explanations for their effects. One possibility is that the effects of emotive visual images are essentially superficial in nature, consistent with the view that feelings aroused by an affective image are transferred somewhat mechanically to a political candidate or cause with which it is paired. This transfer-of-affect explanation suggests that emotional appeals may work best among the least informed voters or those paying the least attention to a persuasive political message. The second possibility is that emotional appeals work via passionate reason, in which affective responses to an emotive image are integrated with, and potentially bias, reasoned thought about the accompanying message. This integrated approach leads to the counterintuitive prediction that individuals who are most highly involved in an issue (and who know the most about it) are most influenced by emotional imagery. This prediction arises from growing evidence that people highly involved in value-laden social issues generate the strongest emotional responses to issue-related persuasive appeals. These two models were tested in a study in which undergraduate students were presented with a picture of a cute or an ugly animal and a flyer from an organization advocating a pro- or anti-environment stance with respect to preserving the animal's habitat. The responses showed that emotive imagery was most persuasive among the most involved environment supporters, providing clear evidence of passionate reasoning.     

Child versus adult psychoanalysis: Two processes or one?

Child analysis continues to be seen as a different technique from adult analysis because children are still involved in a developmental process and because the primary objects continue to play active roles in their lives. This paper argues that this is a false dichotomy. An extended vignette of the analysis of a latency‐aged girl is used to demonstrate that the psychoanalytic process that develops in child analysis is structurally the same as that in adult analysis. Both revolve around the analysis of resistance and transference and use both to promote knowledge of the patient’s mind at work. And both techniques formulate interventions based on the analyst’s appraisal of the patient’s mental organization. It is hoped that stressing the essential commonality of both techniques will promote the development of an overarching theory of psychoanalytic technique.     

Changes in search rate but not in the dynamics of exogenous attention in action videogame players

Many previous studies have shown that the speed of processing in attentionally demanding tasks seems enhanced following habitual action videogame play. However, using one of the diagnostic tasks for efficiency of attentional processing, a visual search task, Castel and collaborators (Castel, Pratt, & Drummond, Acta Psychologica 119:217-230, 2005) reported no difference in visual search rates, instead proposing that action gaming may change response execution time rather than the efficiency of visual selective attention per se. Here we used two hard visual search tasks, one measuring reaction time and the other accuracy, to test whether visual search rate may be changed by action videogame play. We found greater search rates in the gamer group than in the nongamer controls, consistent with increased efficiency in visual selective attention. We then asked how general the change in attentional throughput noted so far in gamers might be by testing whether exogenous attentional cues would lead to a disproportional enhancement in throughput in gamers as compared to nongamers. Interestingly, exogenous cues were found to enhance throughput equivalently between gamers and nongamers, suggesting that not all mechanisms known to enhance throughput are similarly enhanced in action videogamers.