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Author Ezrati, O.; Friedman, J.; Dar, R. pdf  url
doi  openurl
  Title Attenuation of access to internal states in high obsessive-compulsive individuals might increase susceptibility to false feedback: Evidence from a visuo-motor hand-reaching task Type Journal Article
  Year 2019 Publication Journal of Behavior Therapy and Experimental Psychiatry Abbreviated Journal Journal of Behavior Therapy and Experimental Psychiatry  
  Volume (up) 65 Issue Pages 101445  
  Keywords Obsessive-compulsive disorder; Movement; Agency; Proprioception; Proxies  
  Abstract Background and objectives

The Seeking Proxies for Internal States (SPIS) model of obsessive-compulsive disorder (OCD) posits that obsessive-compulsive (OC) individuals have attenuated access to their internal states. Hence, they seek and rely on proxies, or discernible substitutes for these internal states. In previous studies, participants with high OC tendencies and OCD patients, compared to controls, showed increased reliance on external proxies and were more influenced by false feedback when judging their internal states. This study is the first to examine the effects of false feedback on performance of hand movements in participants with high and low OC tendencies.

Method

Thirty-four participants with high OC tendencies and 34 participants with low OC tendencies were asked to perform accurate hand reaches without visual feedback in two separate sessions of a computerized hand-reaching task: once after valid feedback training of their hand location and once with false-rotated feedback. We assessed the accuracy and directional adaptation of participants' reaches.

Results

As predicted, high OC participants evidenced a larger decrease in their hand positioning accuracy after training with false feedback compared to low OC participants.

Limitations

The generalization of our findings to OCD requires replication with a clinical sample.

Conclusions

These results suggest that in addition to self-perceptions, motor performance of OC individuals is prone to be overly influenced by false feedback, possibly due to attenuated access to proprioceptive cues. These findings may be particularly relevant to understanding the distorted sense of agency in OCD.
 
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  ISSN 0005-7916 ISBN Medium  
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  Notes Approved no  
  Call Number Serial 95  
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Author Cantergi, D.; Awasthi, B.; Friedman, J. pdf  url
doi  openurl
  Title Moving objects by imagination? Amount of finger movement and pendulum length determine success in the Chevreul pendulum illusion Type Journal Article
  Year 2021 Publication Human Movement Science Abbreviated Journal Human Movement Science  
  Volume (up) 80 Issue Pages 102879  
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  ISSN 0167-9457 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 111  
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Author Bezalel, G.; Nachoum Arad, G.; Plotnik, M.; Friedman, J. pdf  url
doi  openurl
  Title Voluntary step execution in patients with knee osteoarthritis: Symptomatic vs. non-symptomatic legs Type Journal Article
  Year 2021 Publication Gait & Posture Abbreviated Journal Gait Posture  
  Volume (up) 83 Issue Pages 60-66  
  Keywords Accidental falls; Gait; Knee; Osteoarthritis; Voluntary step  
  Abstract BACKGROUND: Individuals with osteoarthritis fall at a greater rate than the general population, likely as a result of weakness, pain, movement limitations, and a decline in balance. Due to the high prevalence of osteoarthritis in the population, understanding the mechanisms leading to greater fall risk is an important issue to better understand. RESEARCH QUESTION: What is the influence of unilateral knee osteoarthritis on the characteristics of performing a voluntary step (i.e., similar to that performed to avoid a fall after a perturbation), compared to healthy age-matched controls? METHODS: Case-control study performed in a Health maintenance organization physical therapy clinic. The research group consisted of a referred sample of 21 patients with unilateral knee osteoarthritis. The control group consisted of 22 age-matched healthy individuals. All participants were over 65 years of age. Participants were excluded if they had a surgical procedure to back or lower limb within one year before testing, oncological or neurological disease or a deficit in tactile sense. Movements were performed with and without dual tasking. MEASUREMENTS: Duration of the initiation phase (cue to step initiation), preparatory phase (step initiation to foot off) and swing phase (foot off to foot contact). RESULTS: In the preparatory phase and swing phase, the osteoarthritis group moved more slowly than the control group, and these differences were larger for forward compared to backward movements. Dual-tasking slowed responses in the pre-movement initiation stage across groups. SIGNIFICANCE: The differences in basic parameters, and the slower movements in the osteoarthritis group, are consistent with known features of osteoarthritis, being a disease commonly regarded as primarily “mechanical”, and are likely to increase fall risk. These response deficits suggest we should take advantage of advanced rehabilitation techniques, including cognitive loading, to help prevent falls in older adults with osteoarthritis.  
  Address Dept. Physical Therapy, Stanley Steyer School of Health Professions, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel. Electronic address: jason@tau.ac.il  
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  ISSN 0966-6362 ISBN Medium  
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  Notes PMID:33080457 Approved no  
  Call Number Serial 107  
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Author Salzer, Y.; Friedman, J. pdf  url
doi  openurl
  Title Reaching trajectories unravel modality-dependent temporal dynamics of the automatic process in the Simon task: a model-based approach Type Journal Article
  Year 2020 Publication Psychological Research Abbreviated Journal Psychol Res  
  Volume (up) 84 Issue 6 Pages 1700-1713  
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  Abstract The Simon effect represents a phenomenon in which the location of the stimuli affects the speed and accuracy of the response, despite being irrelevant for the task demands. This is believed to be due to an automatic activation of a response corresponding to the location of the stimuli, which conflicts with the controlled decision process based on relevant stimuli features. Previously, differences in the nature of the Simon effect (i.e., the pattern of change of the effect across the distribution of response times) between visual and somatosensory stimuli were reported. We hypothesize that the temporal dynamics of visual and somatosensory automatic and controlled processes vary, thus driving the reported behavioral differences. While most studies have used response times to study the underlying mechanisms involved, in this study we had participants reach out to touch the targets and recorded their arm movements using a motion capture system. Importantly, the participants started their movements before a final decision was made. In this way, we could analyze the movements to gain insights into the competition between the automatic and controlled processes. We used this technique to describe the results in terms of a model assuming automatic activation due to location-based evidence, followed by inhibition. We found that for the somatosensory Simon effect, the decay of the automatic process is significantly slower than for the visual Simon effect, suggesting quantitative differences in this automatic process between the visual and somatosensory modalities.  
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  Series Volume Series Issue Edition  
  ISSN 0340-0727 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30980236 Approved no  
  Call Number Serial 97  
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Author Friedman, J.; Raveh, E.; Weiss, T.; Itkin, S.; Niv, D.; Hani, M.; Portnoy, S. url  doi
openurl 
  Title Applying Incongruent Visual-Tactile Stimuli during Object Transfer with Vibro-Tactile Feedback Type
  Year 2019 Publication Journal of Visualized Experiments : JoVE Abbreviated Journal J Vis Exp  
  Volume (up) 147 Issue Pages e59493  
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  Abstract The application of incongruent sensory signals that involves disrupted tactile feedback is rarely explored, specifically with the presence of vibrotactile feedback (VTF). This protocol aims to test the effect of VTF on the response to incongruent visual-tactile stimuli. The tactile feedback is acquired by grasping a block and moving it across a partition. The visual feedback is a real-time virtual presentation of the moving block, acquired using a motion capture system. The congruent feedback is the reliable presentation of the movement of the block, so that the subject feels that the block is grasped and see it move along with the path of the hand. The incongruent feedback appears as the movement of the block diverts from the actual movement path, so that it seems to drop from the hand when it is actually still held by the subject, thereby contradicting the tactile feedback. Twenty subjects (age 30.2 +/- 16.3) repeated 16 block transfers, while their hand was hidden. These were repeated with VTF and without VTF (total of 32 block transfers). Incongruent stimuli were presented randomly twice within the 16 repetitions in each condition (with and without VTF). Each subject was asked to rate the difficulty level of performing the task with and without the VTF. There were no statistically significant differences in the length of the hand paths and durations between transfers recorded with congruent and incongruent visual-tactile signals – with and without the VTF. The perceived difficulty level of performing the task with the VTF significantly correlated with the normalized path length of the block with VTF (r = 0.675, p = 0.002). This setup is used to quantify the additive or reductive value of VTF during motor function that involves incongruent visual-tactile stimuli. Possible applications are prosthetics design, smart sport-wear, or any other garments that incorporate VTF.  
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  ISSN 1940-087X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:31180348 Approved no  
  Call Number Serial 101  
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