Otto Bock Healthcare Products GmbH

Reliable force control is especially important when using myoelectric upper-limb prostheses as the force defines whether an object will be firmly grasped, damaged, or dropped. It is known from human motor control that the grasping of non-disabled subjects is based on a combination of anticipation and feedback correction. Inspired by this insight, the present study proposes a novel approach to provide artificial sensory feedback to the user of a myoelectric prosthesis using vibrotactile stimulation to facilitate both predictive and corrective processes characteristic of grasping in non-disabled people. Specifically, the level of EMG was conveyed to the subjects while closing the prosthesis (predictive strategy), whereas the actual grasping force was transmitted when the prosthesis closed (corrective strategy). To investigate if this combined EMG and force feedback is indeed an effective method to explicitly close the control loop, 16 non-disabled and 3 transradial amputee subjects performed a set of functional tasks, inspired by the "Box and Block" test, with six target force levels, in three conditions: no feedback, only EMG feedback, and combined feedback. The highest overall performance in non-disabled subjects was obtained with combined feedback (79.6±9.9%), whereas the lowest was achieved with no feedback (53±11.5%). The combined feedback, however, increased the task completion time compared to the other two conditions. A similar trend was obtained also in three amputee subjects. The results, therefore, indicate that the feedback inspired by human motor control is indeed an effective approach to improve prosthesis grasping in realistic conditions when other sources of feedback (vision and audition) are not blocked.

The clinical benefits of microprocessor-controlled prosthetic knees (MPKs) in community ambulators have been well-established. A systematic review in limited community ambulators published in 2014 found benefits in safety, performance-based, and patient-reported outcomes. This work updates the previous analysis to the current state of the published evidence.

Systematic review and meta-analysis of the effect of MPKs in limited community ambulators.

Thirteen research projects presented in 15 publications were identified. Overall validity was "high" in nine studies, "moderate" in three, and "low" in one. The literature described a total of 2366 patients, with 704 classified as limited community ambulators. The use of MPKs in limited community ambulators led to a reduction in falls (SMD g: -0.59; 95% confidence interval (CI) [-0.85, -0.32; I²=0%]), fear of falling (SMD g: 1.2; 95%CI [0.55, 1.85; I²=80%]), risk of falling as indicated by the TUG (SMD g: -0.45, 95%CI [-0.87, -0.02; I²=0%]), an improvement in mobility grade (0.51; 95%CI [0.47,0.55]), self-selected walking speed (SMD g: 0.47; 95%CI [0.14,0.81; I²=0%]), and patient-reported ambulation (MD 9.32; 95%CI [3.61, 15.02; I²=7%]), and utility (MD 7.76; 95%CI [2.05-13.47; I²=0%]). Other outcomes exhibited trends in favor of MPK use or remained insensitive. No outcome was identified favoring non-MPKs.

These results suggest that MPKs may be considered a valuable therapeutic option in limited community ambulators with a transfemoral amputation.Implications for rehabilitationAbove knee amputees may be treated with a large variety of artificial exo-prosthetic knee components.Microprocessor-controlled prosthetic knees have proven to be advantageous and cost effective for community ambulators.The current analysis shows similar effects in safety, mobility, and patient perception also for limited community ambulators.Microprocessor-controlled prosthetic knees are a viable therapeutic option for limited community ambulators.

Wearing time of a prosthesis is regarded as an indicator for success of prosthetic rehabilitation. However, prostheses are frequently worn for esthetic purposes only. Although different supervised measurements to assess prosthetic dexterity are used, it is not clear how performance in such tests translates into actual use in everyday life.

To evaluate the actual daily use of the prosthetic device in patients with below-elbow amputations by recording the number of grasping motions.

Observational study.

Upper extremity function was evaluated using different objective and timed assessments in five unilateral patients with below-elbow amputations. In addition, patients reported daily wearing time, and the number of performed prosthetic movements over a period of at least three months was recorded.

The patients achieved a mean Southampton Hand Assessment Procedure score of 66.60 ± 18.64 points. The average blocks moved in the Box and Block Test were 20.80 ± 7.46, and the mean score in the Action Research Arm Test was 37.20 ± 5.45. The mean time for the Clothespin-Relocation Test was 26.90 ± 11.61 seconds. The patients reported a wearing time of an average of 12.80 ± 3.11 hours per day. The mean number of prosthetic motions performed each day was 257.23 ± 192.95 with a range from 23.07 to 489.13.

Neither high functionality nor long wearing times necessitated frequent use of a prosthesis in daily life. However, frequent daily motions did translate into good functional scores, indicating that regular device use in different real-life settings relates to functionality.