may the DEKA be with you

DARPA handout image shows the DEKA Arm SystemAnd FDA (U.S. Food and Drug Administration) finally said Yes! The robotic arm developed at the the DEKA Research and Development Corp. (founded by Dean Kamen, the smart guy who invented the Segway) has finally been approved as the first prosthetic arm that can carry out multiple, simultaneous movements controlled by signals from electromyogram electrodes (as reported here). Along the lines of what we discussed in a previous post, the DEKA Arm System (codenamed Luke, after Luke Skywalker’s artificial hand) is a prosthetic arm for upper limb amputees (either from the elbow or the shoulder).

With respect to conventional artificial limbs, Luke mainly relies on myoelectricity: via specific electrodes, the electrical activity sent to muscle fibers (absent in case of amputations, but still seeked by firing nerves) is detected and converted into corresponding movements. Besides making the prosthetic control more natural and intuitive for the user, Luke can take advantage of one of the most advanced myoelectric techniques, Targeted Muscle Reinnervation (TMR). Basically, residual nerves from the lost limb can be transplanted and re-wired to the remaining muscular structures. As explained by Wiki, “the goal of TMR is to transfer multiple nerves into separate regions of the targeted muscle, record multiple yet independent signals from the muscle regions, and to use the EMG signals to control a motorized prosthesis sophisticated enough to process multiple control signals”. A Luke-bearing patient could actually feel actual sensations via the prosthetic limb! Luke’s control flexibility is clearly remarkable and is meant to address a wide range of needs from various amputees.

deka2Come on, no drawbacks? There must be an issue with this awesome product! Actually, as discussed on this site, “the real challenge for the Deka arm, as for many other types of sophisticated prostheses, is cost. A simple prosthestic arm (an essentially cosmetic device) can run $3000, while a sophisticated prosthesis can crack $50,000. In many cases, limbs have a relatively short lifespan; it’s not unusual to need a replacement every 3-4 years due to wear and tear on the device”. In any case, in order for Luke’s price to lower a bit, some wise character would say “patience you must have, my young padawan” !



ready to become a superhero ?

I wildly copy-paste here a very interesting article that I found on this webpage 🙂

A group of students from the Royal College of Art in London has developed headsets that allow the wearer to adjust their sight and hearing in the same way they’d control the settings on a TV or radio. The Eidos equipment was developed to enhance sensory perception by tuning in to specific sounds or images amongst a barrage of sonic and visual information, then applying effects to enhance the important ones. “We’ve found that while we experience the world as many overlapping signals, we can use technology to first isolate and then amplify the one we want,” say the designers.

first deviceThe first device is a mask that fits over the mouth and ears to let the wearer hear speech more selectively. A directional microphone captures the audio, which is processed by software to neutralise background noise. It’s then transmitted to the listener through headphones and a central mouthpiece, which passes the isolated sound directly to the inner ear via bone vibrations. “This creates the unique sensation of hearing someone talk right inside your head,” they say. The audio equipment could enable concert-goers to enhance specific elements of a band or orchestra. The designers also suggest that filtering out distracting background noise could improve focus in the classroom for children with ADHD and assist elderly people as their natural hearing ability deteriorates.

second deviceThe second device fits over the eyes and applies special effects – like those seen in long-exposure photography – to what the wearer is seeing in real-time. A head-mounted camera captures the imagery and sends it to a computer, where it’s processed by custom software to detect and overlay movement. It’s then played to the wearer inside the headset, allowing them to see patterns and traces of movement that would normally be undetectable. Possible applications could include sports, allowing teams to visualise and improve technique in real time, and performing arts where effects normally limited to video could be applied to live performance.


Two prototypes styled with faceted surfaces and graduated perforations were presented at the Work in Progress exhibition at the Royal College of Art earlier this year. “Our final objects convey the mixing of digital technology with the organic human body,” explain the team. The Eidos team includes students Tim BouckleyMillie Clive-Smith, Mi Eun Kim and Yuta Sugawara.


Knee Alignment Conditions

The lower limb Mechanical Axis is defined by a line running through the centre of the hip joint to the centre of the ankle joint.  This line should pass essentially through the centre of the knee joint.

The tangential distance of this line from the centre of the knee joint is referred to as the Mechanical Axis Deviation.

In a Varus knee, the axis passes through the knee medial compartment, while in a Valgus knee it crosses the knee lateral side.

Another key concept is the one of Anatomical Axis. The Anatomical Axis of a bone is represented by a line drawn down the centre of the medullary cavity of the bone.

In the femur, the mechanical and anatomical axes deviate whereas in the tibia the mechanical and anatomical axes are essentially represented by the same line.

The angle between the Anatomical Axis of the femur and the lower limb Mechanical Axis is normally 6° of Valgus.

source: this website