CHAPTER 7:
The Doll Factory
Scott K @Kman549
Y’all already know I’m a neuro nerd, but did anyone else see the article in Rehabilitation Journal? The new neural control prosthetics are *amazing*!
DARPA @YesDARPA
@Kman549, if you think that’s amazing, wait until you see what’s coming next!
ChirpChat, March 2041
Despite numerous setbacks, and Glenn’s occasionally bleak attitude, the therapy had progressed well—he was walking, albeit with the assistance of a cane for stability, and could even use that cane with his artificial arm.
Dr. Pillarisetty thought the issues with vision and hearing were psychological, and had been working with him to train himself to see and hear again. Even though the interfaces were perfectly functional, they were not a perfect match to purely biological connections. The human brain could be trained to use the new inputs, but the patient had to want to do so. Many hours of counseling with Nik—one of the few people who would not be swayed by Glenn’s self-pity—were beginning to pay off.
“We’re going to have to put you under for the next one,” Marty had said. “We’re going to do an exploratory procedure to see why your vision and hearing aren’t working right. The engineers think it’s a power connection since that’s the only thing that would account for malfunctions in both. The power distribution built into your bionic processor is reading normal, but they want to check that, too.” Privately, Marty thought there was substance to the idea that the malfunction was all in Glenn’s mind, but the test instruments indicated that at least with the visual prosthetic, the signals were simply not reaching the brain.
“But that’s not what you think, is it? Nik thinks it’s a mental block.”
“I’m not sure what to think. Dr. Pillarisetty is not one-hundred-percent certain about the psychosomatic issues, and as I said, the bioengineers want us to check some things.”
Glenn sat quietly for a few minutes. “How will you be able to tell if it’s working and I’m just ignoring it?”
“Well, I wouldn’t say you’re ignoring the implants.” After a moment, Marty said “Wait, I have an idea,” and left the room. He returned a few minutes later with a portable EEG machine.
After fitting the electrode cap over Glenn’s head, the two of them watched the multiple horizontal lines trace from left to right on the screen. Marty had him put a patch on his left eye, and then flashed a light in his right eye multiple times.
“Okay, now see here, this is the point where the light flashes occurred.” Marty pointed to a spot at the left of the screen. “To the right is an average of all of the flashes. You can see the regular bumps to the left as the visual information passes through the various neural pathways to get to your visual cortex. Now the left eye.”
Glenn moved the patch to his right eye. All he could see was gray nothingness, not even the random flashes he normally got when his eyelids were closed.
“Okay, take the patch off and look. I flashed the light ten times and you never reacted.” Sure enough, the traces on the screen showed only random fluctuations instead of the regular peaks and troughs of the visual signal processing. “Now the hearing.”
He handed Glenn a set of headphones, and for the next few minutes he listened to clicks and beeps or different pitches. When they were finished, Marty showed him a screen comparing the signals recorded as each ear was tested.
“See here with the right ear you have the clicks, the low and the high frequency beeps. You can tell the difference in the two frequencies by the spacing of the peaks. Now on the left you get some of the appropriate bumps for the clicks and beeps, but not the rest of the information. We think a signal’s getting in, but you’re just not decoding it properly.”
“This procedure will fix that?”
“If it’s connectivity, yes.”
“And if not?”
“We cross that bridge when we come to it.” Marty started coiling up the wires from the EEG machine. “Now let’s get this off of you. The nurse will be in here in a few minutes to shave your head for surgery.”
“Again.”
“Yes, again. I don’t know why you’re complaining, Shep. You have a full head of hair, yet you wear it in a buzz-cut, and run your hand through it like a brush all the time. Your left hand, I might remind you.” Marty cocked an eyebrow at him, then rapped a knuckle against his own bald head and ruffled the fringe of hair at the sides.
“Yeah, well, it feels funny now when it’s completely shaved.”
“Sucks to be you, doesn’t it?”
“Right there,” the surgeon said, pointing to the magnified view of Glenn’s left eye.
“Scar tissue?” asked Marty. The two stood off to the side while another surgeon and technologist worked on the auditory prosthetic.
“Not necessarily. It looks like gliosis—but that doesn’t usually happen in the eye. All neurons are surrounded by glial cells. They provide metabolic and structural support and even provide protection where they form the blood-brain barrier. It’s not uncommon to see glial cells encapsulate a recording electrode. However, this doesn’t look like encapsulation and I’m not seeing individual cells.” The surgeon spoke a command to the viewer and it zoomed in on the membrane covering the electrode grid resting on Glenn’s retina.
“That looks fibrous. Just like scar tissue. So, what’s the difference?”
“Yes, that’s what it looks like, but scar tissue like that doesn’t normally grow in a neural environment. Gliosis might occur if the cells grow too much, but what this looks like is the sort of posterior capsule opacity we sometimes see after a cataract lens replacement. This can’t be exactly the same, because we completely removed the lens and its capsule to implant the camera system. However, in those cases, cells just like the ones lining the interior of the eye itself start to grow in the capsule where the natural lens used to be. On the other hand, we certainly disturbed the interior of the ocular space enough to cause some sort of overgrowth.”
“Ok, I can understand that. It’s a natural body defense mechanism, then. What do we do about it, and why doesn’t this happen with other implant patients?”
“Well, we can burn the cells off with an ocular surgery laser. Out of deference to your electronics, we have to do it through an incision on the side instead of going in through the lens. As for why? How long did you wait to have him start using it?”
“He had an extensive rebuild, and the first time we turned everything on, he was overloaded. After that, I didn’t want him to have to adjust to everything at once. I waited for the incisions to heal, and then he was struggling with arm and legs, so we waited some more.”
“Two months? Three? Four?”
“Um . . . we tried it again at six months . . . and it’s been about a year since the last surgical procedure. Why?”
“We see gliosis and scarring around purely passive, record-only electrodes. The small amount of current going through a stimulating electrode usually works to minimize overgrowth. He wasn’t fully activating the system, and it allowed the membrane to grow.”
“So, long term, it should be okay as long as he uses the implant?”
“It should, and we can treat it if it does. That all presumes that he doesn’t actually have a psychological block, like the ear.”
“Actually, he doesn’t have a purely psychological block there, either,” came a voice from the other side of the surgical table.
Marty turned to address the other surgeon who was looking at a scan of Glenn’s brainstem. “What do you see?”
“This, right here.” He indicated a dark spot on the scan right where the spinal cord began to swell into the medulla oblongata. “There was a clot right here above the cochlear nucleus. Now don’t worry, it’s just a spot of necrotic tissue putting pressure on the nucleus and affecting the signals from the cochlea itself. I’m going to laser ablate the mass, hopefully that will relieve the pressure. Otherwise, you’re going to have to go with a surface electrode directly on the auditory cortex.”
“Okay, Dan. Go ahead, once Adrian finishes in the eye. Then we’ll see what Glenn can tell us after he wakes up.”
It wasn’t that simple or that fast. The technology team insisted on doing more tests while they had direct access to the implants, but after twelve hours in surgery and another four in recovery, Marty sat quietly in the darkened room as Glenn slowly opened his eyes.
“Damn, but that’s bright!” Glenn said, then flinched at the sound of his own voice.
Marty reached out and touched a control on his tablet. “I’ve turned down your low-light sensitivity for now,” he whispered.
“You don’t need to shout,” Glenn said in a quiet voice.
“Ah, I take it I can turn down the audio sensitivity as well.” He touched another control, and then commanded the room lights to return to normal illumination. “There, how’s that?”
“Wow,” was all Glenn said for a moment. After several minutes just looking around the room, he continued. “It seems to be getting less sensitive. The room was much too bright at first, but it’s better now. If I look at something for a few moments, it becomes clearer.”
“That’s the active feedback system in the visual sensors. Now that everything is working, the camera that replaced your iris activates electrodes that directly stimulate your retina. However, there’s a processing chip to help you sort through the light levels, distance vision and focus. That’s what you just experienced.”
“And my hearing?”
“More pre-processing there. Cochlear electrodes are ‘known-tech’ but we gave you a lot more selective attention and filtering, and built all of that into the outer part of the ear when we rebuilt the cartilage and skin.”
“Clearly, you fixed the problems. What were they?”
“You had cells growing between the electrode and retina, and pressure on the cochlear nerve. We fixed that without having to do much surgery. The rest of the time was just making sure the electronics were okay.”
Glenn looked up at Marty and smiled—something that had been rare these past few weeks. “So, now the rest of me works. What’s going to keep it from happening again, though?”
Marty sighed. “Well, actually, it’s my fault. The membrane in your eye grew because I waited too long to let you try to use vision. The hearing issue was from not looking at the whole pathway; we found the remains of a clot and were able to remove it. I can’t guarantee that you won’t have more problems, but I can guarantee that it won’t take so long to find the problem as long as you are using sight and sound every day.”
Marty sat in silence for a moment, and Glenn began to worry that there was bad news his doctor was reluctant to share. “Spit it out, Marty. You’ve got bad news. It can’t be too bad because you fixed everything else.”
“It’s not bad—not to me, and not for you. It’s more a matter of it being in your medical record.”
“What’s so bad about something in my record. Space Force retired me, so it’s not like they’re recertifying me as a pilot.”
“It’s more complicated.” Marty paused then blurted out the next bit, “You have a cooling problem, so we put in an Ell-Vad.”
“As in L-V-A-D? A Left Ventricular Assist Device? I have an artificial heart pump?”
“Not so much for your heart. The bionics generate heat. Your body has plenty of ways to get rid of waste heat, as do the arm and leg components, but where any of that is in contact with your biology, you pick up additional heat. The solution is to boost blood and lymph circulation. We used an LVAD pump, but it’s not supporting the left ventricle of your heart, it’s lower down and connected to the lymph circulation.”
“But . . . my medical record now shows that I have what amounts to an artificial heart.”
“Right. Air Force and Space Force fitness regulations have been pretty lenient with respect to artificial limbs, but heart surgery? Even something as benign as boosting lymph circulation could block your flight status.”
“Oh, hell, Marty. I’m half machine as it is, and they already retired me. We’ll just have to cross that bridge when we come to it. We could even argue that the LVAD improves my gee-tolerance!”
“That’s true, I hadn’t thought of it that way. Alright, then.” Marty got up and headed for the door, then turned with a sly smile. “Get some rest and sleep off the anesthetics. Tomorrow we have to go over the radio, recording and remote systems.”
“What are you doing, trying to turn me into some sort of spy?”
“No, not at all, but we still want to get you back into space, LVAD or not. These functions are specifically for that purpose.”
“As you just said, presuming they let me go.”
“They will. You and I just need to make sure Command sees it. It’s time to get you out of the hospital and back to work. You’re going to be officially discharged soon. General Boatright is trying to get you attached to the civilian Space Program, and he’s arguing that you should rejoin astronaut training to show them what you can do. The question is whether you’ll go to Astronaut Basic in Houston at Johnson Space Center, or MarsX crew training in Tucson.”
“Well, okay. Just so I don’t have to go back to Spacer Basic, again.”
“What, you don’t like twenty-mile ruck marches? Didn’t you get the memo? You’re never going to have trouble with those again,” Marty laughed as he exited the room.