|   | 
Details
   web
Records
Author Park, J.; Pazin, N.; Friedman, J.; Zatsiorsky, V.M.; Latash, M.L.
Title Mechanical properties of the human hand digits: Age-related differences Type Journal Article
Year 2014 Publication Clinical Biomechanics Abbreviated Journal
Volume 29 Issue 2 Pages 129–137
Keywords hand; aging; friction; apparent stiffness; damping
Abstract Background

Mechanical properties of human digits may have significant implications for the hand function. We quantified several mechanical characteristics of individual digits in young and older adults.

Methods

Digit tip friction was measured at several normal force values using a method of induced relative motion between the digit tip and the object surface. A modified quick-release paradigm was used to estimate digit apparent stiffness, damping, and inertial parameters. The subjects grasped a vertical handle instrumented with force/moment sensors using a prismatic grasp with four digits; the handle was fixed to the table. Unexpectedly, one of the sensors yielded leading to a quick displacement of the corresponding digit. A second-order, linear model was used to fit the force/displacement data.

Findings

Friction of the digit pads was significantly lower in older adults. The apparent stiffness coefficient values were higher while the damping coefficients were lower in older adults leading to lower damping ratio. The damping ratio was above unity for most data in young adults and below unity for older adults. Quick release of a digit led to force changes in other digits of the hand, likely due to inertial hand properties. These phenomena of “mechanical enslaving” were smaller in older adults although no significant difference was found in the inertial parameter in the two groups.

Interpretations

The decreased friction and damping ratio present challenges for the control of everyday prehensile tasks. They may lead to excessive digit forces and low stability of the grasped object.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0268-0033 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 73
Permanent link to this record
 

 
Author Raveh, E.; Friedman, J.; Portnoy, S.
Title Evaluation of the effects of adding vibrotactile feedback to myoelectric prosthesis users on performance and visual attention in a dual-task paradigm Type Journal Article
Year 2018 Publication Clinical Rehabilitation Abbreviated Journal Clin Rehabil
Volume 99 Issue 11 Pages 2263-2270
Keywords
Abstract Objective: To evaluate the effects of adding vibrotactile feedback to myoelectric prosthesis users on the performance time and visual attention in a dual-task paradigm.

Design: A repeated-measures design with a counterbalanced order of two conditions.

Setting: Laboratory setting.

Subjects: Transradial amputees using a myoelectric prosthesis with normal or corrected eyesight (N=12, median age=65 ± 13 years). Exclusion criteria were orthopedic or neurologic problems.

Interventions: Subjects performed grasping tasks with their prosthesis, while controlling a virtual car on a road with their intact hand. The dual task was performed twice: with and without vibrotactile feedback.

Main measures: Performance time of each of the grasping tasks and gaze behavior, measured by the number of times the subjects shifted their gaze toward their hand, the relative time they applied their attention to the screen, and percentage of error in the secondary task.

Results: The mean performance time was significantly shorter (P=0.024) when using vibrotactile feedback (93.2 ± 9.6 seconds) compared with the performance time measured when vibrotactile feedback was not available (107.8 ± 20.3seconds). No significant differences were found between the two conditions in the number of times the gaze shifted from the screen to the hand, in the time the subjects applied their attention to the screen, and in the time the virtual car was off-road, as a percentage of the total game time

(51.4 ± 15.7 and 50.2 ± 19.5, respectively).

Conclusion: Adding vibrotactile feedback improved performance time during grasping in a dual-task paradigm. Prosthesis users may use vibrotactile feedback to perform better during daily tasks, when multiple cognitive demands are present.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0269-2155 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Penn State @ write.to.jason @ Serial 89
Permanent link to this record
 

 
Author Portnoy, S.; Mimouni-Bloch, A.; Rosenberg, L.; Offek, H.; Berman, T.; Kochavi, M.; Orman, G.; Friedman, J.
Title Graphical Product Quality and Muscle Activity in Children With Mild Disabilities Drawing on a Horizontally or Vertically Oriented Tablet Type Journal Article
Year 2018 Publication American Journal of Occupational Therapy Abbreviated Journal Am J Occup Ther
Volume 72 Issue 6 Pages 1-7
Keywords
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0272-9490 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Penn State @ write.to.jason @ Serial 91
Permanent link to this record
 

 
Author Kaufman-Cohen, Y.; Friedman, J.; Levanon, Y.; Jacobi, G.; Doron, N.; Portnoy, S.
Title Wrist Plane of Motion and Range During Daily Activities Type Journal Article
Year 2018 Publication American Journal of Occupational Therapy Abbreviated Journal Am J Occup Ther
Volume 72 Issue 6 Pages 1-10
Keywords
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0272-9490 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 92
Permanent link to this record
 

 
Author Salzer, Y.; Friedman, J.
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 84 Issue 6 Pages 1700-1713
Keywords
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0340-0727 ISBN Medium
Area Expedition Conference
Notes PMID:30980236 Approved no
Call Number Serial 97
Permanent link to this record