Eitan Raveh

Visuomotor behaviors and performance in a dual-task paradigm with and without vibrotactile feedback when using a myoelectric controlled hand

ABSTRACT Prosthesis users allocate visual attention to their prosthetic hand while performing activities of daily living (ADLs), due to absence of sensory feedback. Dual-task assignments present competition for visual attention and may affect the performance of ADLs. Vibrotactile feedback (VTF) is a frequently-used method to provide prosthesis users with tactile feedback. However, the effect of adding VTF on visual attention and performance in a motor dual-task paradigm has not been investigated. Our aim was to compare visual attention and performance during ADLs in a motor dual-task paradigm when using binary VTF and without using VTF. Forty-three able-bodied subjects (age 26 ± 6.6 years) had a myoelectric-controlled hand attached to their right hand. The dual task comprised of a computer game played with the left hand, while manipulating objects with the artificial hand. This was performed with and without VTF in a counter-balanced order of two conditions. An eye-tracker monitored visual attention, while time to complete each task and the time the virtual car went off-road were recorded. No significant differences were found in visual attention or in performance time between the two conditions. Further examination of adding VTF to prosthesis users is recommended, with disrupted visual feedback and basic grasping tasks.

Prevention of Genu Recurvatum in Poststroke Patients Using a Hinged Soft Knee Orthosis

To evaluate the effect of a hinged soft knee orthosis on the gait pattern and symmetry of poststroke patients with chronic symptoms and knee hyperextension.

Adding vibrotactile feedback to a myoelectric-controlled hand improves performance when online visual feedback is disturbed

We investigated whether adding vibrotactile feedback to a myoelectric-controlled hand, when visual feedback is disturbed, can improve performance during a functional test. For this purpose, able-bodied subjects, activating a myoelectric-controlled hand attached to their right hand performed the modified Box & Blocks test, grasping and manipulating wooden blocks over a partition. This was performed in 3 conditions, using a repeated-measures design: in full light, in a dark room where visual feedback was disturbed and no auditory feedback - one time with the addition of tactile feedback provided during object grasping and manipulation, and one time without any tactile feedback. The average time needed to transfer one block was measured, and an infrared camera was used to give information on the number of grasping errors during performance of the test. Our results show that when vibrotactile feedback was provided, performance time was reduced significantly, compared with when no vibrotactile feedback was available. Furthermore, the accuracy of grasping and manipulation was improved, reflected by significantly fewer errors during test performance. In conclusion, adding vibrotactile feedback to a myoelectric-controlled hand has positive effects on functional performance when visual feedback is disturbed. This may have applications to current myoelectric-controlled hands, as adding tactile feedback may help prosthesis users to improve their functional ability during daily life activities in different environments, particularly when limited visual feedback is available or desirable.

Myoelectric Prosthesis Users Improve Performance Time and Accuracy using Vibrotactile feedback when Visual Feedback is disturbed

OBJECTIVE To evaluate the effects of adding vibrotactile feedback (VTF) in myoelectric prosthesis users during performance of a functional task when visual feedback is disturbed. DESIGN A repeated-measures design with a counter-balanced order of 3 conditions. SETTING Laboratory setting. PARTICIPANTS Transradial amputees using a myoelectric prosthesis with normal or corrected eyesight (N=12, median age 65±13y). Exclusion criteria were orthopedic or neurologic problems. INTERVENTIONS All participants performed the modified Box and Blocks Test, grasping and manipulating 16 blocks over a partition using their myoelectric prosthesis. This was performed 3 times: in full light, in a dark room without VTF, and in a dark room with VTF. MAIN OUTCOME MEASURES Performance time, that is, the time needed to transfer 1 block, and accuracy during performance, measured by number of empty grips, empty transitions with no block and block drops from the hand. RESULTS Significant differences were found in all outcome measures when VTF was added, with improved performance time (4.2 vs 5.3s) and a reduced number of grasping errors (3.0 vs 6.5 empty grips, 1.5 vs 4 empty transitions, 2.0 vs 4.5 block drops). CONCLUSIONS Adding VTF to myoelectric prosthesis users has positive effects on performance time and accuracy when visual feedback is disturbed.

Evaluation of the effectiveness of a novel gait trainer in increasing the functionality of individuals with motor impairment: A case series

ABSTRACT Regaining the ability to independently ambulate following a physical disability can increase functional ability and participation of patients in daily life. Gait trainers are assistive devices that enable body support and provide safety during gait. However, most conventional gait trainers are pre-configured to a constant position, therefore not suitable for practicing sit-to-stand function, and require assistance from a caregiver in order to mount the device from a sitting position. We therefore evaluated the effectiveness of a dynamically-adjusting gait trainer, designed to provide independence and safety during gait and various activities, in both lab setting and at home in four subjects (one female, three males, ages 32–79 years) with limited ambulation. Spatiotemporal parameters and gait symmetry were recorded, as well as activity levels, actual use of device, and satisfaction. Although gait parameters and physical activity levels were not notably improved, and in one case were worsened, three subjects reported positive experience with the gait trainer. The new gait trainer may have advantages in supporting users with limited mobility during walking and various functions and decrease the risk for falls. A longer practice time and individual fitting process are recommended for better accommodation to the new possibilities.