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Ezrati, O., Friedman, J., & Dar, R. (2019). 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. Journal of Behavior Therapy and Experimental Psychiatry, 65, 101445.
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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Portnoy, S., Mimouni-Bloch, A., Rosenberg, L., Offek, H., Berman, T., Kochavi, M., et al. (2018). Graphical Product Quality and Muscle Activity in Children With Mild Disabilities Drawing on a Horizontally or Vertically Oriented Tablet. Am J Occup Ther, 72(6), 1–7.
Abstract: OBJECTIVE. We compared performance level and muscle activity patterns during shape copying and tracing in two positions, while sitting at a desk and while standing in front of a wall, between typically developing (TD) preschool children and children with mild disabilities (MD).
METHOD. Twenty-two TD children (8 boys, 14 girls; mean [M] age 5 5.2 yr, standard deviation [SD] 5 0.1) and 13 children with MD (9 boys, 4 girls; M age 5 4.9 yr, SD 5 0.5) participated in this study.
RESULTS. The children performed faster and smoother movements when copying shapes on the vertical surface, with no reduction of accuracy, than on the horizontal surface. Children with MD exerted their upper trapezius while performing the short tasks on the vertical surface compared with their muscle activity on the horizontal surface.
CONCLUSION. Incorporating short copying or drawing tasks on a vertical surface may increase the control of proximal muscles and ease graphomotor performance in children with MD.
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Kaufman-Cohen, Y., Friedman, J., Levanon, Y., Jacobi, G., Doron, N., & Portnoy, S. (2018). Wrist Plane of Motion and Range During Daily Activities. Am J Occup Ther, 72(6), 1–10.
Abstract: OBJECTIVE. The dart-throwing motion (DTM) is a multiplane wrist motion that is needed for many daily occupations. Mobilization along the DTM plane may be essential for rehabilitation after wrist injury, but DTM angles are reported for the dominant hand alone, so their relevance to injury in the nondominant hand cannot be surmised. The aim of this study was to quantify the DTM plane angles for both hands during different activities of daily living (ADLs).
METHOD. Forty-three healthy participants wore a twin-axis electrogoniometer during ADLs.
RESULTS. No significant differences were found between the DTM plane angles of the dominant (20°�45°) and nondominant (15°�40°) hands. These angles varied by task and across participants.
CONCLUSION. The DTM plane is a functional motion used by both hands during ADLs. Because the DTM plane angle differs among hands, tasks, and individual clients, wrist rehabilitation involving the DTM plane should not be limited to a singular DTM plane angle.OBJECTIVE. The dart-throwing motion (DTM) is a multiplane wrist motion that is needed for many daily occupations. Mobilization along the DTM plane may be essential for rehabilitation after wrist injury, but DTM angles are reported for the dominant hand alone, so their relevance to injury in the nondominant hand cannot be surmised. The aim of this study was to quantify the DTM plane angles for both hands during different activities of daily living (ADLs).
METHOD. Forty-three healthy participants wore a twin-axis electrogoniometer during ADLs.
RESULTS. No significant differences were found between the DTM plane angles of the dominant (20°�45°) and nondominant (15°�40°) hands. These angles varied by task and across participants.
CONCLUSION. The DTM plane is a functional motion used by both hands during ADLs. Because the DTM plane angle differs among hands, tasks, and individual clients, wrist rehabilitation involving the DTM plane should not be limited to a singular DTM plane angle.
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Cantergi, D., Awasthi, B., & Friedman, J. (2021). Moving objects by imagination? Amount of finger movement and pendulum length determine success in the Chevreul pendulum illusion. Human Movement Science, 80, 102879.
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Bezalel, G., Nachoum Arad, G., Plotnik, M., & Friedman, J. (2021). Voluntary step execution in patients with knee osteoarthritis: Symptomatic vs. non-symptomatic legs. Gait Posture, 83, 60–66.
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.
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