On the development of a cybernetic prosthetic hand

The human hand is the end organ of the upper limb, which in humans serves the important function of prehension, as well as being an important organ for sensation and communication. It is a marvellous example of how a complex mechanism can be implemented, capable of realizing very complex and useful tasks using a very effective combination of mechanisms, sensing, actuation and control functions. In this thesis, the road towards the realization of a cybernetic hand has been presented. After a detailed analysis of the model, the human hand, a deep review of the state of the art of artificial hands has been carried out. In particular, the performance of prosthetic hands used in clinical practice has been compared with the research prototypes, both for prosthetic and for robotic applications. By following a biomechatronic approach, i.e. by comparing the characteristics of these hands with the natural model, the human hand, the limitations of current artificial devices will be put in evidence, thus outlining the design goals for a new cybernetic device. Three hand prototypes with a high number of degrees of freedom have been realized and tested: the first one uses microactuators embedded inside the structure of the fingers, and the second and third prototypes exploit the concept of microactuation in order to increase the dexterity of the hand while maintaining the simplicity for the control. In particular, a framework for the definition and realization of the closed-loop electromyographic control of these devices has been presented and implemented. The results were quite promising, putting in evidence that, in the future, there could be two different approaches for the realization of artificial devices. On one side there could be the EMG-controlled hands, with compliant fingers but only one active degree of freedom. On the other side, more performing artificial hands could be directly interfaced with the peripheral nervous system, thus establishing a bi-directional communication with the human brain

Development of a portable sensorised handle for the objective assessment of the effectiveness and concordance of intervention plans in dementia

Dementia is a global issue which is rising rapidly, with 46.8 million people worldwide living with dementia in 2015. This number is expected to increase to 74.7 million by 2030. Some researches show that some kinds of exercises, such as resistance band exercises, would help to improve the memory and other abilities in patients with dementia. However, the true effectiveness of these activities is not really known due to the lack of objective assessment of efforts done during the long intervention time. Moreover, there is no way of measuring the actual activities performed by the patient without direct observation. As a consequence, it is impossible to measure the concordance between the patient and the therapist

An implanted antenna system for the monitoring of the healing of bone fractures

An implanted antenna system consisting of two monopoles attached on a metal plate for the monitoring of the healing of bone fractures has been investigated. The proposed structure has been simulated on a three layer body phantom model and the S2i response of the system is evaluated as the bone fracture that is introduced in the phantom gradually heals turning from blood to bone marrow and bone cortical in five discrete steps

Bone fracture monitoring using implanted antennas in the radius tibia and phalange heterogeneous bone phantoms

This paper proposes an innovative technique for monitoring the healing of severe bone fractures using a pair of radio frequency monopoles implanted in the fractured bone. It is envisaged that the screws and external fixation used to stabilise and align the bone will also act as monopole antennas. The proposed antenna configurations were measured inside three novel heterogeneous bone phantoms representing the radius, tibia and phalange bones, and the results were compared to computer simulations with a voxel model of a 26-year-old female from CST Microwave Studio's Virtual Family. The power transmitted from one monopole to the other (S 21) was measured and evaluated as an indicator for fracture healing as blood emulating liquid was injected inside the phantom emulating the conditions of a bone fracture. Finally, for the validation of the phantom measurements, an ex-vivo measurement was conducted using a lamb femur bone. In all cases, the power transmitted from one monopole to the other through the fracture decreased significantly as the volume of the blood representing the fracture increased. The proposed system could provide doctors with a quantitative monitoring tool regarding the healing progress of a fractured bone through the reduction of the wound's hematoma during the first four weeks after the trauma that are critical for bone restoration

Control of multifunctional prosthetic hands by processing the electromyographic signal

The human hand is a complex system, with a large number of degrees of freedom (DoFs), sensors embedded in its structure, actuators and tendons, and a complex hierarchical control. Despite this complexity, the efforts required to the user to carry out the different movements is quite small (albeit after an appropriate and lengthy training). On the contrary, prosthetic hands are just a pale replication of the natural hand, with significantly reduced grasping capabilities and no sensory information delivered back to the user. Several attempts have been carried out to develop multifunctional prosthetic devices controlled by electromyographic (EMG) signals (myoelectric hands), harness (kinematic hands), dimensional changes in residual muscles, and so forth, but none of these methods permits the "natural" control of more than two DoFs. This article presents a review of the traditional methods used to control artificial hands by means of EMG signal, in both the clinical and research contexts, and introduces what could be the future developments in the control strategy of these devices

Anatomical calibration through post-processing of standard motion tests data

The inertial measurement unit is popularly used as a wearable and flexible tool for human motion tracking. Sensor-to-body alignment, or anatomical calibration (AC), is fundamental to improve accuracy and reliability. Current AC methods either require extra movements or are limited to specific joints. In this research, the authors propose a novel method to achieve AC from standard motion tests (such as walking, or sit-to-stand), and compare the results with the AC obtained from specially designed movements. The proposed method uses the limited acceleration range on medial-lateral direction, and applies principal component analysis to estimate the sagittal plane, while the vertical direction is estimated from acceleration during quiet stance. The results show a good correlation between the two sets of IMUs placed on frontal/back and lateral sides of head, trunk and lower limbs. Moreover, repeatability and convergence were verified. The AC obtained from sit-to-stand and walking achieved similar results as the movements specifically designed for upper and lower body AC, respectively, except for the feet. Therefore, the experiments without AC performed can be recovered through post-processing on the walking and sit-to-stand data. Moreover, extra movements for AC can be avoided during the experiment and instead achieved through the proposed method

The mediation effect of political interest on the connection between social trust and wellbeing among older adults

Previous research has established significant positive associations between social trust and wellbeing among older adults. This study aimed to obtain a deeper understanding of the relationship between different sources of social trust and wellbeing by examining the mediational role of political interest. A sample of 4,406 Italian residents aged 65 years and over was extracted from a national cross-sectional survey during 2013 in Italy, representative of the non-institutionalised population. Measures included trust in people, trust in institutions, political interest, life satisfaction and self-perceived health. Mediation path analysis and structural equation modelling were used to test the mediation effects of political interest on the relationship between trust in people and trust in institutions with life satisfaction and self-perceived health. Associations between trust in people, life satisfaction and self-perceived health, and between trust in institutions and life satisfaction were partially mediated by political interest, while the association between trust in institutions and self-perceived health was fully mediated by political interest. Having high levels of political interest may thus enhance the relationship between social trust and wellbeing among older adults. These results suggest that interventions to enhance wellbeing in older adults may benefit from examining individuals’ levels of political interest

Wavelet thresholding technique for sEMG denoising by baseline estimation

The surface electromyography (sEMG) signal is affected by different sources of noises: current technology is considerably robust to the interferences of the power line or cable motion artefacts, but still there are many limitations in denoising the baseline. In this paper, we introduce a new technique, named baseline adaptive denoising algorithm (BADA), for denoising the sEMG signal by wavelet thresholding procedure. In particular, the thresholds are estimated using the same baseline signal with fixed and adaptive techniques. Eventually, we verify that the proposed adaptive method performs better than the standard Donoho technique and different variations, in term of noise cancellation and distortion of the signal, quantified by a new suggested indicator of the denoising quality. Copyright © 2012 Inderscience Enterprises Ltd

Development of an ultra-miniaturized inertial measurement unit for jaw movement analysis during free chewing

Problem statement: Jaw movement analysis, as a clinical aid, can provide an objective basis for understanding and diagnosing jaw musculoskeletal disorders. Therefore, the use and development of devices for quantitatively measuring and analyzing jaw movement have become more common and popular in the clinic. Many types of jaw tracking devices have been developed, but most of them are still not handy and easy to be used. Approach: To improve the handiness and utility of the jaw movement analysis devices, we developed a simple to be used jaw tracking prototype by using a new ultra-miniaturized Inertial Measurement Unit (IMU) named WB-3. The WB-3 IMU was composed by 3-axis gyroscope, 3-axis accelerometer and 3-aixs magnetometer, which can not only measure the acceleration and angular speed of jaw movement, but also can measure mouth opening angle. The IMU's extremely reduced weight and size allowed it to be easily adhered to mandible during normal tests without physical restriction to the subjects. A preliminary experiment for jaw movement analysis during free chewing of three types of food with different shapes and hardness was evaluated. A group of 15 healthy subjects aged from 21-36 years old kindly participated in the experiment. Results: The parameters of chewing time, chewing frequency, power spectrum density of jaw's angular speed and acceleration, cumulative distribution function of jaw's acceleration and mouth opening angle were presented. The experimental results clearly showed that the subjects used less chewing time, less chewing frequency, less acceleration cumulative distribution and energy to eat soft food; higher values were found in the case of hard food and there was no significant difference in mouth opening angle while eating these three foods. Conclusion: Our jaw movement analysis prototype using IMU WB-3 was proved to be a valid and handy method for jaw movement and pattern analysis which may be used clinically as an assistant system for dental therapy. © 2010 Science Publications

Age-related decrements in dual-task performance: Comparison of different mobility and cognitive tasks. A cross sectional study

This cross-sectional study investigated the age-related differences in dual-task performance both in mobility and cognitive tasks and the additive dual-task costs in a sample of older, middle-aged and young adults. 74 older adults (M = 72.63±5.57 years), 58 middle-aged adults (M = 46.69±4.68 years) and 63 young adults (M = 25.34±3.00 years) participated in the study. Participants performed different mobility and subtraction tasks under both single and dual-task conditions. Linear regressions, repeated-measures and one-way analyses of covariance were used, The results showed: significant effects of the age on the dual and mobility tasks (p<0.05) and differences among the age-groups in the combined dual-task costs (p<0.05); significant decreases in mobility performance under dual-task conditions in all groups (p<0.05) and a decrease in cognitive performance in the older group (p<0.05). Dual-task activity affected mobility and cognitive performance, especially in older adults who showed a higher dual-task cost, suggesting that dual-tasks activities are affected by the age and consequently also mobility and cognitive tasks are negatively influenced