Adding A Gentle Touch To Prosthetic Limbs With Somatosensory Stimulation

June 30, 2021 by Maya Posch 5 Comments

When Nathan Copeland suffered a car accident in 2004, damage to his spinal cord at the C5/C6 level resulted in tetraplegic paralysis. This left him initially at the age of 18 years old to consider a life without the use of his arms or legs, until he got selected in 2014 for a study at the University of Pittsburgh involving the controlling of a robotic limb using nothing but one’s mind and a BCI.

While this approach, as replicated in various other studies, works well enough for simple tasks, it comes with the major caveat that while it’s possible to control this robotic limb, there is no feedback from it. Normally when we try to for example grab an object with our hand, we are aware of the motion of our arm and hand, until the moment when our fingers touch the object which we’re reaching for.

In the case of these robotic limbs, the only form of feedback was of the visual type, where the user had to look at the arm and correct its action based on the observation of its position. Obviously this is far from ideal, which is why Nathan hadn’t just been implanted with Utah arrays that read out his motor cortex, but also arrays which connected to his somatosensory cortex.

As covered in a paper by Flesher et al. in Nature, by stimulating the somatosensory cortex, Nathan has over the past few years regained a large part of the sensation in his arm and hand back, even if they’re now a robotic limb. This raises the question of how complicated this approach is, and whether we can expect it to become a common feature of prosthetic limbs before long. Continue reading “Adding A Gentle Touch To Prosthetic Limbs With Somatosensory Stimulation” →

Alice Ball Steamrolled Leprosy

June 15, 2021 by Kristina Panos 22 Comments

Leprosy is a bacterial disease that affects the skin, nerves, eyes, and mucosal surfaces of the upper respiratory tract. It is transmitted via droplets and causes skin lesions and loss of sensation in these regions. Also known as Hansen’s disease after the 19th century scientist who discovered its bacterial origin, leprosy has been around since ancient times, and those afflicted have been stigmatized and outcast for just as long. For years, people were sent to live the rest of their days in leper colonies to avoid infecting others.

The common result of injecting chaulmoogra oil. Image via Stanford University

Until Alice Ball came along, the only thing that could be done for leprosy — injecting oil from the seeds of an Eastern evergreen tree — didn’t really do all that much to help. Eastern medicine has been using oil from the chaulmoogra tree since the 1300s to treat various maladies, including leprosy.

The problem is that although it somewhat effective, chaulmoogra oil is difficult to get it into the body. Ingesting it makes most people vomit. The stuff is too sticky to be applied topically to the skin, and injecting it causes the oil to clump in abscesses that make the patients’ skin look like bubble wrap.

In 1866, the Hawaiian government passed a law to quarantine people living with leprosy on the tiny island of Moloka’i. Every so often, a ferry left for the island and delivered these people to their eventual death. Most patients don’t die of leprosy, but from secondary infection or disease. By 1915, there were 1,100 people living on Moloka’i from all over the United States, and they were running out of room. Something had to be done.

Professor Alice Ball hacked the chemistry of chaulmoogra oil and made it less viscous so it could be easily injected. As a result, it was much more effective and remained the ideal treatment until the 1940s when sulfate antibiotics were discovered. So why haven’t you heard of Alice before? She died before she could publish her work, and then it was stolen by the president of her university. Now, over a century later, Alice is starting to get the recognition she deserves.

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Digital X-Ray Scanner Teardown Yields Bounty Of Engineering Goodies

June 14, 2021 by Dan Maloney 12 Comments

We’ll just go ahead and say it right up front: we love teardowns. Ripping into old gear and seeing how engineers solved problems — or didn’t — is endlessly fascinating, even for everyday devices like printers and radios. But where teardowns really get interesting is when the target is something so odd and so specialized that you wouldn’t normally expect to get a peek at the outside, let alone tramp through its guts.

[Mads Barnkob] happened upon one such item, a Fujifilm FCR XG-1 digital radiography scanner. The once expensive and still very heavy piece of medical equipment was sort of a “digital film system” that a practitioner could use to replace the old-fashioned silver-based films used in radiography, without going all-in on a completely new digital X-ray suite. It’s a complex piece of equipment, the engineering of which yields a lot of extremely interesting details.

The video below is the third part of [Mads]’ series, where he zeroes in on the object of his desire: the machine’s photomultiplier tube. The stuff that surrounds the tube, though, is the real star, at least to us; that bent acrylic light pipe alone is worth the price of admission. Previous videos focused on the laser scanner unit inside the machine, as well as the mechatronics needed to transport the imaging plates and scan them. The video below also shows experiments with the PM tube, which when coupled with a block of scintillating plastic worked as a great radiation detector.

We’ve covered a bit about the making of X-rays before, and a few of the sensors used to detect them too. We’ve also featured a few interesting X-ray looks inside of tech, from a Starlink dish to knock-off adapters.

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Trials Begin For Lozenge That Rebuilds Tooth Enamel

June 2, 2021 by Kristina Panos 48 Comments

For all the cool regenerative tricks the human body can do, it’s kind of weird that we only have one shot at tooth enamel with no way to get it back. That may be about to change, as researchers at the University of Washington have developed a lozenge that rebuilds this precious protective coating a few microns at a time and are taking it to the trial stage. Could it really work? It’s certainly something to chew on.

The lozenge uses a genetically-engineered peptide (a chain of amino acids) derived from a protein that’s involved in developing enamel in the first place, as well as with the formation of the root surface of teeth. Inside the lozenge, this peptide works alongside phosphorus and calcium ions, which are the building blocks of tooth enamel. It’s designed to bind to damaged enamel without harming the gums, tongue, or other soft tissues of the mouth.

The researchers have already verified the efficacy on teeth extracted from humans, pigs, and rats, so the trials will largely revolve around comparing it to other whitening methods and documenting their findings.

One added advantage is that the new enamel the lozenges produce is really white, because it’s brand new. These lozenges sound like an all-around great solution, especially compared with traditional whitening techniques that often make enamel weaker. The researchers are also developing an over-the-counter toothpaste and some kind of solution for hypersensitivity, which is right up our alley.

We are skeptical of course, because nothing in history thus far has been able to regenerate enamel. Then again, yours truly uses toothpaste with nano-hydroxyapatite, which is touted as a non-toxic version of the same mineral that makes up teeth and bones. Skepticism abounds with that stuff, too, although my grill looks better to me. But why settle for new enamel when you could regrow entire teeth?

Main image by Eric Moreau and thumbnail image by Kevin Bation via Unsplash

Algae Gene Gives Blind Man Some Light-Based Sight

June 1, 2021 by Kristina Panos 8 Comments

What are single-celled organisms good for, you may wonder? Science has found a wonderful new use for one of them — restoring partial sight to people with inherited forms of blindness. More specifically, they took a gene from algae that responds to light and moves toward it in order to replace dead or defective photo-receptor cells that lie between the human pupil and the optic nerve.

When light enters the eye, it triggers photo-receptor cells that in turn send signals to nerve cells called ganglions. These add information about motion and send the complete picture to the brain via the optic nerve. The researchers basically hacked the ganglion cells and turned them into photo-receptors. First they used a virus to get light-sensing molecules called chrimson into one of the retinas of the lone volunteer they’d managed to train before the pandemic. He’d been wearing the goggles out on walks and told them he could see the stripes of the crosswalk.

They were able to get him into the lab in summer 2020, where he donned a pair of goggles that register light changes and send amber light into the eye whenever that happens. He also wore a cap full of electrodes so the researchers could see what parts of his brain lit up when the goggles do their thing. With the goggles on and ready to fire, the man was able to distinguish whether a black cup was in front of him, and was even able to count multiple cups correctly most of the time. Although this is not a full restoration of vision, it’s an excellent development in that direction, and we’re excited to see where it goes.

In the future, the researchers hope to slim down the goggles into something more fashionable. Combine them with these camera-enabled shoes, and accessibility goes way up.

Thanks for the tip, [foamyguy]!

Self-Driving Or Mind Control? Which Do You Prefer?

May 24, 2021 by Orlando Hoilett 9 Comments

We know you love a good biohack as much as we do, so we thought you would like [Tony’s] brainwave-controlled RC truck. Instead of building his own electroencephalogram (EEG), he thought he would use NeuroSky’s MindWave. EEGs are pretty complex, multi-frequency waves that require some fairly sophisticated circuitry and even more sophisticated signal processing to interpret. So, [Tony] thought it would be nice to off-load a bit of that heavy-lifting, and luckily for him, the MindWave headset is fairly hacker-friendly.

EEGs are a very active area of research, so some of the finer details of the signal are still being debated. However, It appears that attention can be quantified by measuring alpha waves which are EEG content between 8-10 Hz. And it seems as though eye blinks can be picked from the EEG as well. Conveniently, the MindWave exports these energy levels to an accompanying smartphone application which [Tony] then links to his Arduino over Bluetooth using the ever-so-popular HC-05 module.

To control the car, he utilized the existing remote control instead of making his own. Like most people, [Tony] thought about hooking up the Arduino pins to the buttons on the remote control, thereby bypassing the physical buttons, but he noticed the buttons were a bit smaller than he was comfortable soldering to and he didn’t want to risk damaging the circuit board. [Tony’s] RC truck has a pistol grip transmitter, which inspired a slightly different approach. He mounted the servo onto the controller’s wheel mechanism, allowing him to control the direction of the truck by rotating the wheel using the servo. He then fashioned another servo onto the transmitter such that the servo could depress the throttle when it rotates. We thought that was a pretty nifty workaround.

Cool project, [Tony]! We’ve seen some cool EEG Hackaday Prize entries before. Maybe this could be the next big one.

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Thought Control Via Handwriting

May 16, 2021 by Al Williams 12 Comments

Computers haven’t done much for the quality of our already poor handwriting. However, a man paralyzed by an accident can now feed input into a computer by simply thinking about handwriting, thanks to work by Stanford University researchers. Compared to more cumbersome systems based on eye motion or breath, the handwriting technique enables entry at up to 90 characters a minute.

Currently, the feat requires a lab’s worth of equipment, but it could be made practical for everyday use with some additional work and — hopefully — less invasive sensors. In particular, the sensor used two microelectrode arrays in the precentral gyrus portion of the brain. When the subject thinks about writing, recognizable patterns appear in the collected data. The rest is just math and classification using a neural network.

If you want to try your hand at processing this kind of data and don’t have a set of electrodes to implant, you can download nearly eleven hours of data already recorded. The code is out there, too. What we’d really like to see is some easier way to grab the data to start with. That could be a real game-changer.

More traditional input methods using your mouth have been around for a long time. We’ve also looked at work that involves moving your head.