Short term microgravity effect on isometric hand grip and precision pinch force with visual and proprioceptive feedback

Experiments executed on the upper limb are assuming increasing significance in the frame of the Human Physiology in space, for at least two reasons: the upper limb is the principal means of locomotion for the subject living in a space station; furthermore, fatigue can have a significant effect on the hand, for the ordinary work on board, and in particular for the extra-vehicular activities. The degradation of the performances affecting the muscular-skeletal apparatus can be easily recognized on the upper limb, by exerting specific scientific protocols, to be repeated through the permanence of the subject in weightlessness conditions. Another aspect relevant to the effect of microgravity on the upper limb is associated with the alteration of the motor control programs due to the different gravity factor, affecting not only the bio-mechanics of the subject, but in general all his/her psycho-physical conditions, induced by the totally different environment. Specific protocols on the upper limb can facilitate the studies on learning mechanisms for the motor control. The results of such experiments can be transferred to the Earth, useful for treatment of subjects with local traumas or diseases of the Central Nervous System.

Strain sensing fabric for hand posture and gesture monitoring

Monitoring body kinematics and analyzing posture and gesture is an area of major importance in bioengineering and several other connected disciplines such as rehabilitation, sport medicine and ergonomics. Recent developments of new smart materials consent the realization of a new generation of garments with distributed sensors. What we present here is a sensing glove able to detect the posture and movements of the hand.

A two DoF finger for a biomechatronic artificial hand

Current prosthetic hands are basically simple grippers with one or two degrees of freedom, which barely restore the capability of the thumb-index pinch. Although most amputees consider this performance as acceptable for usual tasks, there is ample room for improvement by exploiting recent progresses in mechatronics design and technology. We are developing a novel prosthetic hand featured by multiple degrees of freedom, tactile sensing capabilities, and distributed control. Our main goal is to pursue an integrated design approach in order to fulfill critical requirements such as cosmetics, controllability, low weight, low energy consumption and noiselessness. This approach can be synthesized by the definition "biomechatronic design", which means developing mechatronic systems inspired by living beings and able to work harmoniously with them. This paper describes the first implementation of one single finger of a future biomechatronic hand. The finger has a modular design, which allows to obtain hands with different degrees of freedom and grasping capabilities. Current developments include the implementation of a hand comprising three fingers (opposing thumb, index and middle) and an embedded controller.

Neural interfaces for regenerated nerve stimulation and recording

A class of implantable, regeneration-type neural interfaces (NI's) for mammalian peripheral nerve recording and stimulation were developed using different fabrication processes and integrating purposely designed components. A typical NI comprises three main components: 1) a microfabricated silicon die incorporating a microelectrode array on multiple through-holes, 2) a polymer guidance channel housing the die, and 3) a flexible flat cable connecting the die to an external electronic circuitry. The design and fabrication of the NI's were aimed at achieving long term, reliable implants by taking into careful account the biological, electrical, and mechanical requirements of the specific implant site. Different versions of the NI were fabricated and implanted between the severed ends of the sciatic nerve in a mammalian animal model (rabbit). Morphological and histological evidence showed that nerves regenerated through the NI's and electrophysiological results demonstrated the recovery of electrical functionality. Moreover, the NI's allowed stimulation of the regenerated nerve producing a visible leg/foot contraction. The NI's presented in this paper are being further improved in the authors' laboratories with the ultimate goal of allowing the control of nerve motor and sensory functions in future prosthetic devices.

Compression of the deep palmar branch of the ulnar nerve: clinical and electromyographic findings after a new method of decompression

Five cases of compression of the deep palmar branch of the ulnar nerve were operated upon and the hiatus released by subperiosteal removal of the pisiform bone. The clinical and electromyographical results after a minimum follow-up of eight months showed an improvement in all cases. The authors stress the importance of accurate electromyographic examination for a correct preoperative diagnosis.

Perichondrial wrist arthroplasty--a follow-up study in 17 rheumatoid patients

The author analyzes the long-term results of a new method of arthroplasty in the rheumatoid wrist. The new method, performed in 17 patients over four years, consists of reconstruction of the joint surfaces with perichondrial grafts. The functional and clinical results are analyzed. All patients showed overall subjective and objective improvement. Moreover, the new functional stability of the wrist remained constant throughout the follow-up period. No recurrence of joint deformity or synovitis was observed. The method is recommended for patients with painful, unstable, or dislocated wrists and in those with ankylosis in the nonfunctional wrist.

Perichondrial wrist arthroplasty in rheumatoid patients

A new method is proposed for reconstruction of the wrist joint in rheumatoid arthritis. Perichondrial arthroplasty done in four patients with severe deformity of the wrist from rheumatoid arthritis gave functionally improved results. In one case biopsy of the reconstructed joint showed newly formed cartilaginous tissue four months after initial surgery.

[Personal clinical and neurophysiological experience in the surgically treated carpal tunnel syndrome]

In 18 cases of carpal tunnel syndrome treated by surgical decompression of the median nerve, a neurophysiological control was performed before and after surgery. In all cases improvement or disappearance of the pain was observed; improvement in motor function was less constant. Control of the median nerve conduction showed that in all cases with preoperative distal latency less than 6 msec. there was a normalization of the nerve conduction after only 3 months. In cases of distal latency over 6 msec, and especially in those with complete motor conduction block, the latency remain within patological limits even 15 months after surgery. This may be explained either by a slower conduction of the regenerated fibres or by a persistent myelinic and axonal damage of the nerve.

The cartilaginous potential of the perichondrium in rabbit ear and rib. A comparative study in vivo and in vitro

In an experimental study the cartilaginous protential of the rabbit ear perichondrium has been compared with that of the rib in vivo and in vitro. Perichondrium was transferred as free autologous grafts to the subcutaneous tissue on the scalp and as loose bodies into the knee joint. The presence of cartilage in the grafts was examined after six weeks. In vitro explants of rabbit perichondrium from the ear and the rib were maintained in an organ culture system. The presence of cartilage was analyzed after one to three weeks. Rabbit perichondrium from the rib appeared to have a greater cartilaginous potential than that from the ear both in vivo and in vitro. Chondrogenesis in perichondrium was demonstrated in vitro.

[Muscular malformation of the wrist in an initial carpal tunnel syndrome. Clinical case]

A carpal canal syndrome in a young female subject was found at the operating table to be due to a wrist muscle abnormality. An extra muscle leaving the styloid process of the radius in the direction of the transverse ligament of the carpus, and an abnormal distal development of the muscular belly of the superficial flexor of the third finger, had led to compression on the median nerve corresponding to the carpal canal. Check on motor and sensitive conduction of the median nerve revealed nerve damage at wrist level. Removal of the extra muscle and section of the transverse ligament of the carpus resolved the painful symptomatology. Control of nervous conduction two months after operation confirmed the improvement.