A surgeon is giving patients VR instead of sedatives | Hacker News Reader

A surgeon is giving patients VR instead of sedatives

bbc.com

98 pointspmcpinto97 comments

Distraction works really well in general; even without VR.

The dentist discovered that my 3 year old son has a bit of caries; but she said that filling a cavity for small kids like him is only possible under anaesthesia. I thought this sounded ridiculous.

My girlfriend found a different dentist who specialized on treating kids. She performed the procedure without any anaesthesia or sedatives by using lots of distractions, including a magic wand and elaborate stories about dwarves wandering in the forest of teeths.

I wish my dentist distracted me like that :)

Complete medical newbie here... What is wrong with anaesthesia?

The risk of any side effects, especially in a yet-to-fully-develop human? I wouldn't be surprised if the list included coma because someone got the dosage wrong. It's just not worth the risk at that point.

(Disclaimer: I have nothing to do with medicine)

You are mixing local anesthesia with complete pass-out by using NO2 or similar for surgeries (which has 1:10000 mortality ratio if I recall correctly) and side effects.

Local anesthesia can be even in form of spray instead of injection, depends on severity. Heck, once I tried to chew coca leaves and that got me pretty numb in my mouth for quite some time, couldn't articulate properly etc.

It's still chemistry put into the body messing up with pain signaling, but I wouldn't worry that much about it (or you'll go crazy with all possible things that could harm a kid one way or the other)

PLEASE do not state fear-mongering numbers without source, especially about medicine! Anesthesia is safer than traveling by plane, nowadays. According to a 10 sec googling, the mortality is now sub 10/million/year, and that's including high-risk populations. source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697561/

US commercial airlines haven't had a fatal accident since 2009. I think that's a better apple than 'traveling by plane'.

But even those numbers show that the death rate for kids aged 0-4 is significantly higher[1] than for older kids and young adults. I know that doctors on the whole really try to avoid having to put kids under for just this reason.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697561/figure/...

The common guideline is 6 mo and 2 yo. Those ages are commonly viewed as cutoffs for risk levels. In our hospital for example, the presence of an attending will be required for induction/waking up of anesthesia under 2 years old. Under 6 months, the risk of respiratory complication is far greater, which is why surgery is withheld until that age, except in emergencies.

PLEASE understand the meaning of "if I recall correctly". I was wrong.

Not everybody is attempting to write a post in an online forum about in form or article for Nature or Science, backchecking every statement in every sentence. Jeez

I do understand. It's not a problem for me. But look at all the terrorized people commenting on this story. They already think anesthesia means death to the kids, or something. You are not helping them.

> I have nothing to do with medicine

And yet your response is just supposition ("I wouldn't be surprised if...").

Anesthesia is fine.

The classic risk in dental procedures is the dentist using a lidocaine-adrenalin mix, which when injected into a vessel (by mistake), will make your heart race, your blood pressure skyrocket, and provoke a general sense of unease/impending doom. It is also the main reason why many people say they are "allergic" to anesthesia. In fact, the complication profile of amide-class local anesthetics is very safe. As for the interaction of anesthesia with development, scientific evidence is scarce and anesthesia alone does not seem to have such a great impact on the long term. Anyway, I would be far more worried about hypnotic drugs than local anesthetics in that regard.

> a lidocaine-adrenalin mix, which when injected into a vessel (by mistake), will make your heart race, your blood pressure skyrocket, and provoke a general sense of unease/impending doom

Wait, that's not supposed to happen? I pretty much just figured oh well, it's epi, what are you gonna do.

> The classic risk in dental procedures is the dentist using a lidocaine-adrenalin mix, which when injected into a vessel (by mistake), will make your heart race, your blood pressure skyrocket, and provoke a general sense of unease/impending doom.

And there's a fun side-effect, or at least I had that: body learns to completely blow up under stress. Before I went through that I had very low stress impact (psychological stress had no physical impact), since then stressful situations almost lock me up (heart racing, muscles contracting, …). It's really quite annoying.

> and provoke a general sense of unease/impending doom

Oh shit I thought I was just weird. Do you have any more information on that? I felt that when I was getting a crown put in, it was horrifying, "impending doom" is the perfect description.

It also happened the (one) time I donated blood, though I don't remember being given any injections or anything though; but I felt that EXACT same "impending doom" sensation; at the time I thought basically "well this is the end, they accidentally took too much blood and I'm going to die now". I felt cold to the core and started sweating horribly and spontaneously, just like the time at the dentist.

>I felt cold to the core and started sweating horribly and spontaneously

Isn't that low blood pressure ? I felt that once when I had food poisoning, collapsed to the ground after having insane stomach pain for an hour trying to get to the phone to call ambulance, fortunately by the time I got up it cleared up.

I don't know; at the time, I generally had high blood pressure, and I don't know anything about what might cause it to raise/lower in the short-term (obviously losing blood would, but I dunno if a controlled, intentional blood-drawing for a donation would be enough)

I definitely agree that it works wonders. When I was a child I had a dentist work on my teeth using the same technique, albeit it was jokes instead of story-telling.

As a kid, I had a dentist who refused to use local anaesthesia, he thought it was 'bullshit' and I shouldn't be able to feel anything. The pain was indescribable. I'm still traumatised by it and haven't been to the dentist in years. I would literally shit my pants out of fear (not exaggerating here, I would have to wear a diaper to undergo regular treatment even with local anaesthetics).

Just the though of being operated on while fully conscious gives me the shivers. The only thing I can image being scarier is when they have to do brain surgery and they wake you up halfway through while your skull is open.

I'm currently on a waiting list for a specialist at the local hospital where they can treat you under general anaesthesia. It's the only way I can be treated after my childhood experiences. unfortunately the waiting list is long. I just hope it's my turn before something starts to really hurt.

I had one treatment under GA before, about 8 years ago, and it was the first and only non-traumatic dentist experience in my life. It was such a huge difference with the 'regular' experience that I simply can't understand why dentists insist on letting people experience the torture. I think they are all secretly sadists that get off on hurting people.

I'm not trying to scare you, just make sure your kid is okay with it because it could fuck him up for life.

My friend was in the Marines and had to get is wisdom teeth removed. Lucky for him they were training Marine dentist at his base.

He said they wiped some type of numbing gel and proceeded to grab his wisdom teeeth out with pliers. The trainee couldn't get them out so the instructor climbed on his chest and yanked them out.

I can confirm. I had the same experience minus the trainee. Had my wisdom teeth extracted while in the Marines. It was over in less than 30 seconds - no time for anesthesia to kick in nor do I remember him administering any. Crack, crack, yank - done.

Much depends on the position of the teeth. Pulling some with pliers would cause so much bleeding that choking could kill the patient (teeth still well below gum line).

You could just do the operation with the patient laying face-down on a massage table (the kind with a head-hole), so that the blood runs out of their mouth instead of down their throat. Might be a lot of blood loss, though; you'd want to wear goggles while doing the yanking. :)

My wisdom teeth happened to come in pretty straight and level. When I was in the Army, the dentist there suggested having them taken out during AIT (primary MOS training school), but it wasn't an order. I nope'd right out of that because I had heard about a dozen stories like yours.

My wisdom tooth extraction was a minor disaster. I have an extremely sensitive gag reflex, and the surgeon just couldn't do his job. Had to knock me out.

Go to the dentist, you do not want bad teeth. Brushing and flossing 2x/day is not always enough (and 1x almost never is).

Can confirm. 23 years old, 5 years no dentist, aggressive paradontosis with 2 teeth already dead and a lot of gum recession. Can't eat apples or steaks any more. Go to your god damn dentist.

I feel your pain, i'm in a similar boat with less excuse. Any recommendations for choosing a dentist? I've got a lot of work to be done, so i want someone competent, friendly, etc. I fear price gouging for something that is already more expensive than i can afford.

I've got so much work to be done i need to construct a long term "game plan" with this to-be dentist. So, yea.

edit: I should add a bit of "dentist phobia" as well, i suppose. I don't claim it normally, but my heart is racing just reading this thread -_-

I live in Europe so I unfortunately cannot recommend ways to find the best dentist in the states. Dentists here choose depending on need first because a lot is covered by insurance anyway. However you should definitely see more than one dentist and ask all of them for a care plan. It's called therapy and cost plan here, there surely is something similar everywhere.

By the way, don't be scared. I have no excuse also, and thats very liberating. Distance yourself from the story in the head - for it is root of all suffering in this world. Underneath, everything is and is okay like that.

30, haven't been to a dentist in 9 years. Scared to go, but no pain or bleeding. I brush every other day...

That being said, I've had a lot of work done -- the front to half of most of my teeth is fake. The fake enamel saved my molars. I know this because my last dentist was a preventative and let's fixa problem when it is a problem type, not an aggressive one.

I do not understand why fake enamel is not standard. It works -- I'm proof. It's almost like dentist want you to suffer and use their services.

I suspect it depends on your diet as well. I am less good at brushing/flossing than I used to be, but have a healthier diet (less processed foods) and go sometimes for years without needing anything beyond plack removal.

No matter what you do (or your dentist does), if you have bad lymphatic circulation, any sinus infection has potential to turn into a root-pulp infection necessitating a root canal. I've had five of those—and no cavities—in the last four years.

I finally decided to research the problem, and ended up taking diosmin (not for any of its on-label uses, but simply by the logic of its pharmacodynamics: it increases lymphatic flow rate, like blood thinners increase blood flow rate.) Eliminated a bunch of other circulation problems I never really realized I had at the same time.

A big part of it is that going under general anesthesia is more dangerous than not going under general anesthesia.

It's also more expensive than a vial of lidocaine and takes longer.

I had a filling put in last year. Local anesthetic only. No pain. Took about 20 minutes.

I've had a few procedures done over the past year (root canal, extraction, wisdom-tooth extraction) all under local anaesthetic. Quick and painless, just like your experience.

The pain is not the issue, being stuck in the chair is. I get really anxious just getting a haircut.

I was not trying to tell you how you should experience dental treatment.

I did feel it was useful to respond to It was such a huge difference with the 'regular' experience that I simply can't understand why dentists insist on letting people experience the torture. I think they are all secretly sadists that get off on hurting people. with my contrasting experience.

Counter anecdote - I've had a few root canals and fillings in the last few years. The first one was with a doctor who refused to re-apply the local. I was all but climbing out of the chair from the pain.

Went to another dentist a few years later to let the experience dull in my mind - this one would re-apply the local, which made the experience tolerable, but hardly pain free. And that doesn't cover for the feeling/sound of the drill. And the smell. Gods below, the smell of burning tooth, root, and plastic... That's me you're burning up there!

Seriously thinking about GA next time.

Many dentists use water cooled drills. Shop around?

I do have the good fortune of having seen the same dentists for 20 years.

When you say local, you do mean a novocaine injection, right? Not just the numbing gel they smear on your gums first?

Tell your next dentist that you're very sensitive to pain, and they'll up the amount of novocaine, and the locations they inject it. I suffered for awhile before telling the dentist, and making them take me seriously, and they started injecting more, making the procedure bearable.

> a novocaine injection, right

Indeed.

> Tell your next dentist that you're very sensitive to pain

That's what I did. Still wasn't pain free, apparently I have deep roots, and Novocain wears off faster. Bad luck, I guess.

My guess would be that GA is an order of magnitude more dangerous than most routine dentist procedures like root canals or teeth extraction. Most people would rather suffer through the pain than add extra risk to the operation.

I'm with you, in that I avoid anaesthesia when possible, but be careful making sweeping statements about "most people" without having some data to back it up. My off-hand guess is that "most people" would prefer GA.

> Most people would rather suffer through the pain than add extra risk to the operation.

That might be true when people are making decisions about their kids. I question whether it's true of people making decisions for themselves.

Is avoiding pain really a good reason for GA? At least in my dental procedures (and I've had quite a few for my age), the operations itself where uncomfortable, but the painful part was afterwards, when the anesthetics wore off.

Depends on the type of pain. The pain afterwards I can manage, the pain during is of a completely different magnitude.

But even if they could guarantee it would be 100% painless, I would opt for GA every time. The problem is being operated upon while fully aware of what is happening. We don't even treat animals that badly. If you bring your dog to the vet to have tooth fixed they put him under, but a human has to suffer through the experience ?

GA can be extremely dangerous for some people. I know someone who has had several knee surgeries without GA because they don't handle GA well enough to make it worth the risks (death, for example). There are very good reasons why a lot of procedures are done without GA.

It is highly likely that even if your relative is very sick, the odds of him/her dying due to general anesthesia are pretty low. The amount of people for whom GA itself is "extremely dangerous" is extremely small. Anesthesiologists optimize. Their job is to counsel you on what they think is best, to lower the odds of complication. We often have to put people under who are very, very sick due to surgical constraints. A crushing majority of the time, nothing bad happens. It's all a question of lowering the probability.

I suspect the opposite.

A few years ago I had to have a gastroscopy and the doctor was baffled that I refused GA.

Motivations vary wildly. My mother actually had root canal treatments with no anesthetics whatsoever, solely to save money on anesthetics. OTOH my SO now saves money to get all her teeth fixed under GA, because of her fear of dentists.

That is only looking at the physical part though. It doesn't take into account the psychological damage that is done. I'm pretty sure I've got a form of PTSD as a result of my childhood dentist experience and I suspect my anxiety issues are at least somewhat related to it.

GA may be "an order of magnitude" more dangerous if you are already very sick or have it administered by a non-specialist. In the hands of someone who knows what he is doing, the risks are orders of magnitude lower than even crossing the street to go to work every day.

There are two main real reasons why a dentist prefers to go without GA:

- no need: most dental procedures are minor, and well-conducted local anesthesia is sufficient. Unfortunately, dentists often underestimate the pain and anxiety generated by some of their actions.

- not alone anymore: if you want anesthesia, you have no other alternative than getting a specialist, who will have to be paid. Furthermore, the anesthesia provider will interfere in care decisions if required, making him a pain for the dentist.

So yeah, mainly money...

Are you saying this with awareness of claims like this?

http://www.medicalnewstoday.com/articles/294966.php

Is that difference statistically significant? For those who don't have time to click the link, they looked at 53 kids who received GA and 53 who didn't. The average IQ of the first group was 5-6 points below the second. Now the stdev of one IQ is 15, so the stdev of the average of 53 is 15/sqrt(53)=2.06. The stdev of the difference of two such averages is then 2.06*sqrt(2)=2.91. A 5-point difference is then a 1.72 sigma event and a 6-point move a 2.06 sigma event, and the probabilities of more extreme events are 4.3% and 2%. I guess that's statistically significant, but not by much.

Look, I didn't read the paper, and it's not the only one.

I had a cavity filled last year and the dentist told me about how when he was a child, he went to a dentist who didn't use local anesthetics and he felt everything.

He didn't say it but I suspect that he went into dentistry to save other people from what he experienced.

Soviet dentists didn't use anesthesia either. I experienced quite a few visits that would probably be considered war crimes if they were done to captured combatants. It took a long time for me to be able to visit the dentist regularly.

I'm sorry what you went through, and I agree - let the kids have anaesthesia.

People often wake up dumber after general anesthesia.

Ok, it looks like I wasn't clear enough: when I wrote anaesthesia, I meant general anaestesia (narcosis). (English is not my primary language.)

Narcosis for filling a minor cavity seems like something that should only be necessary as a last resort.

I wouldn't have a problem with local anaesthesia, but it just wasn't necessary in this case.

He came home from the dentist and told me how he turned on the tap with his magic wand. No sign of trauma anywhere.

What you wrote was clear to me.

It seems a bit unlikely a dentist would be able to distract a kid from excruciating pain.

I don't know how old you are, but old medical theory stated that babies, and by extension small children, did not feel pain due to their nervous system being immature. By "old theory", I mean no more than 30-40 years... Needless to say, the attitude towards that has completely changed since then, and dental care for children is now commonly done under general anesthesia when necessary.

As for children being potentially struck for life by that, you are absolutely correct. It is also valid in adults, as I have been unfortunate enough to witness first hand during my younger years.

So you risk a kids excruciating pain on the mere promise of a doctor being good with distractions?

And for what?

Do you mean general anesthesia, or local, or just the nitrous oxide?

If the cavity doesn't reach the nerve, it's probably painless. But if any serious dental work needs to be done that's going to hurt, telling jokes isn't going to do it.

Signed, someone who grew up under the soviet dental system that didn't use anesthesia, and consequently suffered what would amounts to torture during several visits.

This kind of process is akin to clinical hypnosis (which falls within the realm of anesthesia, not surgery). Anesthesiologists have had the opportunity to specialize in clinical hypnosis for a few years now. However, the cost-effectiveness is difficult to demonstrate, because it requires staff to be totally involved in it, so you can no longer roam several ORs at once. I guess this is where VR comes in...

It is explicitly stated in the article that the patient received a local anesthetic - the VR environment is only used to replaced the sedative (commonly used to used to distract the patient, not to remove physical pain)

Hypnosis can be and is used with regional anesthesia for such indications. It depends on the stress level of the patient, and whether specialized staff is available. You are right about the article, of course.

Yeah, same as VR, I don't suppose hypnosis removes pain - probably just provides a distraction to make sure the brain doesn't fill in the pain and discomfort the eyes are saying should be here.

Reminds me of Mark Cuban's experiment with VR to relieve a health problem:

http://blogmaverick.com/2016/07/16/virtual-reality-gave-me-m...

Not quite the same thing, but my dentist lets me watch Netflix with noise cancelling headphones. I had a crown put in over 1.5 hours with anesthetic but lots of drilling and I almost didn't notice it was happening. It felt like barely 30 minutes had passed.

The place is called Studio Dental if you're looking in SF.

Wow, now I wish my dentist allowed that!

How did you watch Netflix? Cardboard set?

VR instead of sedatives, not instead of locals. This is vr mitigating mental stress not dulling actual pain. There have already been many studies linking vr to reduced requests for painkillers in childens hospitals, dulling real pain. That it too works to distract old people is no great leap.

Yeah, it's not really a surprise that VR benefits patients undergoing surgery. What would you rather see during an operation? A sterile room with surgeons roaming around you, or a virtual calming environment?

Maybe I'm just a sick fuck, but I really enjoyed watching when they tore open my big toe a bit to remove an ingrown nail. If I recall correctly, they even put up a barrier so I wouldn't be able to see, but I asked them to take it down.

I also like watching the needle go in when they draw blood or give me a shot.

"Sick fuck" seems a bit harsh. I've always put it down to spending my first few years in and out of hospitals all the damn time; it was either learn to deal or go crazy, and while some no doubt would argue strongly for the latter, at the very least it's fair to say I did both.

I'm the opposite. I can't even watch fake needles go "into" arms on television.

Lol. Ive been on one set where the needles were real. Hiring a EMT to do a saline drip on a stand-in's arm for a closeup is cheaper than the fake rig.

This makes me wonder how often that's the case; how many real injections have I seen?

How about neither and you just knock me out completely ?

The only time I've been awake for surgery they pumped me so full of drugs that the sterile room was the best thing ever and for about an hour or two afterwards I wanted to go back for more surgery so that I could get more of those awesome drugs.

I had something done under something akin to "twilight sleep" - it was oral surgery, and I took a pill in a doctor's office. It came out of a bottle stored in a safe, and I understand why - I was so afraid of the procedure, I started crying after taking the pill, but 10 minutes later I calmed down, and then I remember nothing - except a brief blip of the surgeon suturing something in my mouth - until getting home.

Apparently I was awake and responsive enough to follow instructions throughout the procedure, but as far as my memory is concerned, it simply didn't happen.

No wonder they kept those pills in a safe.

Dont care. Put me to sleep and let the docs use whatever environment they think best. I dont plan on participating much let alone judge the decor.

Some people like having a sense of control. They may rather be aware of what's happening.

Some surgeries can even take place without local anesthetics using only hypnosis (thyroidectomy, for example). I will however readily admit that opiates are often liberally used as an adjunct to hypnosis, and that cases where hypnosis works well enough to withhold anesthetic drugs are not that common.

Did you read the article? Yes, hypnosis can work (although an episode of 'House M.D.' comes to mind), but that doesn't relate to the point being made here.

Yes I did read the article. I must however admit that I commented based on personal experience instead of the article. My bad.

There is a great DrCox bit on youtube about hypnosis anesthetics. Some people can make a go of it, but there is a reason they still "restrain" such patients and keep a big needle of morphine on standby.

Eventually we will develop the game:

https://en.m.wikipedia.org/wiki/The_Game_(Star_Trek:_The_Nex...

Dammit! I hadn't lost the game in years.

https://imgs.xkcd.com/comics/anti_mind_virus.png

It's over, you're welcome

Also the game ended back in like 2010 when someone called quads and rolled quads.

http://fortune.com/2015/08/26/resolution-games-funding/

they're already on it don't worry

This makes me think of SnowWorld, a VR project which was used to help people take their mind off the pain when recovering from severe burns. The idea is that they play in virtual snow and it actually soothes the burn by distracting them from the physical pain and making them think of cool snow and ice.

https://www.hitl.washington.edu/projects/vrpain/

It's talked about in the article, but thanks for linking it.

This is highly related to the Master Project we are doing at university right now. Trying to make games that have players using a relaxation technique in a playful way. Reading through the papers on the topic at the beginning of the project you could see that this stuff really works and works well. There are even attempts to treat mental problems like PTSD with VR. Exciting stuff.

If this is effective on people getting cut open, I wonder how effective such a thing could be to cut stress even in daily life!

Anyone know of any good "calming" games on Steam that might help to de-stress after a long day? I used to play Journey to chill out, but I don't have a ps3 anymore, and even that game gets old after a while.

Sounds fine for people who are resistent to motion sickness.

But, especially in a medical setting, what would they do if the patient became nauseated during surgery? Surely that can't be beneficial.

And lying in bed while all senses tell your body you are stationary and only your eyes say "no, we are actually standing and the world is moving around us" will cause motion sickness. It is a normal response from the body.

So you would be basically switching the sedatives with drugs to combat motion sickness when you want to use VR.

I don't know much about what causes motion sickness - My only experience was when I was developing a game for the Vive and I manually moved the CameraRig. How hard do you have to try to trick the body? Would sitting so your back and head are upright (and legs bent at ~90 degree angle) be enough? What if you were laying down but sitting up?

We need help:

Children's Hospital Colorado (CHC) serves from the Mexican to the Canadian border via it's Flight for Life program [1] that air-lifts children and adults in dire need to the ICU in Aurora. One of the not so nice parts of a children's ICU ward, and ICU care in general, is the issue of ICU psychosis [2][3]. In short, to keep you alive after severe trauma physicians must run the risk of inducing mental trauma (please read the citations for further information). Children can also undergo ICU psychosis. To compensate, anti-depressants and pain medications are prescribed to lessen the mental trauma, but these drugs also have interactions with other drugs and are thought to prolong recovery.

Virtual Reality devices like the MS Hololens and the Occulus Rift may be able to help lessen the toll on these poor children by lessening the use of psychoactive drugs, increasing the rate of recovery, and decreasing the length of stay in critical care. AirBnB has a system like Google-Street view, but for apartment listings; you can take a virtual tour of the listing in VR and see if you like it. CHC could really use something like this for the kids.

Imagine you are a 7 year old. Your last memory before waking up in the ICU was your mother and father being killed in an automobile accident. You wake up surrounded by strange beeping machines, you are no longer breathing, there are tubes in every hole in your body pumping in and out vital fluids and gasses, the doctors may have even made new holes in you to keep your blood moving, you are restrained in the bed to keep you from tearing out these life-saving methods, you are likely drugged to deal with the pain and mostly incoherent. This is a nightmare for just about any person, but it is especially terrible for children. Many people come out of ICU care with PTSD, many children come out with PTSD. VR devices could allow these patients to 'take five' and return virtually to their homes via the AirBnB like systems. These children could run in their back-yards or play in their rooms again, if only for an hour.

C.S. Mott Children's Hospital in Michigan has run some pilot research with children [4] and the results are optimistic. The US Army has run some other pilot studies using VR for PTSD with returning Vets via the Bravemind program [5] and these results indicate success in using VR as a PTSD treatment. The limited results thus far indicate that VR in the ICU may be a viable method for recovery from severe trauma.

This is where we need your help, HackerNews. Children are suffering. We need hackers, programmers, and administrative people to help get VR devices into hospitals and determine the efficacy of using these devices as treatment. I am not a 'CS' person, not like you all are. We need your expertise. Honestly, we don't know what is going to happen in the end, but we have to give it a shot. The kids need for us to give it the ol' college try.

If you are interested in helping and have the time to dedicate, please email me (email is in my user-account). Thank you for reading this and for your time, we all appreciate it.

[1] https://www.childrenscolorado.org/doctors-and-departments/de...

[2]http://www.medicinenet.com/icu_psychosis/article.htm

[3]https://www.theatlantic.com/health/archive/2015/06/the-overl...

[4] https://www.youtube.com/watch?v=RIgxRhz6lmM

[5] http://ict.usc.edu/prototypes/pts/

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