 Hello guys, this marks the second in the series I'm doing, hopefully all this month, on explaining different parts of autism, especially the less talked about side of it. As I said last time, I'm gonna be touching on why some autistic individuals are nonverbal and why, even among the verbal autistic, they seem to communicate less and even parts of how they vocalize seems to be different. I know I've spent enough comments in my channel, I'm aware of it, I can't do much about it. So I'll be explaining why. So if you didn't know, roughly a third of autistic individuals are nonverbal. Even among the verbal autistic, they tend to communicate less. This partially manifests as just socializing less, although there's many reasons why that's the case, but that is part of it. Rich pathologists have been noticing this for a while and for several decades, the idea was oh well they just don't know that they're supposed to socialize, and we sort of talked about that in my last video and now it's probably not the case, and it's not the case. One of the fantastic things that more modern technology has provided is the ability to type because you don't need to find motor control to do that. And so individuals like what I mentioned last time with Carly Fleischman was believed to not be able to communicate and not understand the people around her, type, communicate that way and sort of shock the parents because they had been speaking as if in front of her as if she was there, totally aware of everything. This started getting people to look at things differently. And what some speech pathologists started to notice is that if you carefully write down the exact phonemes that are being produced, they're biased in particular directions. So especially with the like semi-verbal, it's not really a good name for it, but the individuals who are able to produce vocalizations, but they're not the complex, sophisticated stuff that we call language, you notice patterns and it's specifically biased towards vowels and what are called plosives, which are a specific type of consonant. You're a little uncertain what a plosive is, I'm not going to go into too much detail, but puh, or the beginning of plosive is a plosive, that kind of more forced, not really nuanced to it or like with a lot of other consonants. This got them thinking, and if you are a speech therapist or speech pathologist, you might already be on the right track after I had just said that. This got them thinking, are there structural or motor differences in autism? Another one of the things that sort of got them thinking this that have been noticed for a while anyways is that there is altered prosody and that is a specific part of speech dealing with sort of the overall flow of the speech. If you pay attention and you're going to be now that I'm going to mention this, like my speech there tends to be much more emphasized pauses a lot of the time and after there is a pause the very next vocalization is more emphasized. This is the altered prosody finding. So this got them especially more recently starting to look into what is going on here. There's clearly differences that we can identify. Why? One of the techniques for doing so was to take recordings and analyze the waveform that resulted as well as to do imaging of the throat while the individual was talking. There are a lot of studies involving this. I'm not going to talk about every single one because I'm going to be horribly boring but I've got four that I just want to mention. The first is from a Yasuhiro Kaki Hara and others and the findings because I'm not going to bore you with the specific numbers and metrics and all of that was that there tended to be a noticeable elevation in pitch and difficulty starting the vocalization but not carrying through the rest of the vocalization. So this was an actuation at the very beginning but once you got speaking it was largely fine. They suspected that this was probably lip strain, that the difficulty getting the lips to move at first. Another study that looked at it in a different way was by Ahijit Mahanta. I'm sorry if I butchered that, I almost certainly did. The findings there was that there was a higher vocal fold vibration so that part of the throat vibrated more rapidly than it would normally. This is obviously going to change how you speak. That it took more effort to vocalize, that this was not just in the lips but throughout the entire throat there was a very impulse-like excitation. So there was a strain to get the vocalization at first and then when it happened it was very sudden, jerky kind of movement. And they also noticed a structural difference in the pharyngeal oral tract, the vocal tract was shortened and this would be because the pharyngeal muscles aren't constricting as much, which sort of ties into the other muscle issues that I've been describing. Yao Santos, which I probably butchered as well, I'm sorry, didn't have any novel findings as far as what was going on but took many of the models that were already being done and tried applying them to much younger ages than they were already done and was able to find that you can start to identify these differences as early as 18 months old. Then a more comprehensive study was done by DK Aller and others where they just looked at taking a bunch of these techniques and validating their accuracy. Holding them up under much higher scrutiny than was originally done. So no new findings again, but verified the models in fact work. Overall these are surprisingly accurate given that it's something that's basically never talked about as far as autism goes and that you can correctly identify whether the person is autistic or not based on a local sample, anywhere between like 84 to 97% accuracy, which is phenomenal. And you've probably noticed by the names that I've given, this has been done in numerous different countries with essentially identical findings, so this isn't local to specifically the United States or some other country, this seems to apply to autism in general. So a little summary of what the findings were in that there are structural differences, like the Jordan-Larengeal tract, but more importantly is the motor differences because these are actually the same motor differences that have been observed otherwise, that the impulse like the difficulty getting the muscles to start moving, and then when they do it's a little too much, you have to bring that in, that's observed throughout most of the skeletal muscles, even some of the non-skeletal muscles, which is fun, but when it comes down to nonverbal children, it's not that the autistic child doesn't know that they need to speak, it's not that they're being defiant or anything like that, it is quite literally that they can't get their muscles to move in the ways that are necessary to produce speech, so that's unfortunate, but some things that I have found useful working in with other autistic individuals who are much more affected than I am, consider options like having them write down messages on a piece of paper or type them out on a computer, nearly everybody has phones or tablets nowadays, so it's very easy to do that, if that's something that they're able to do, and it seems like that's one of the easier options, then that would be a fantastic way to still be able to communicate, that's important, there's still a person there, it's just that their muscles aren't working right, and they still have preferences on things, all of that, I see a lot of the time, just assume that a person's not speaking, they're too far gone, just gonna, you know, we're out eating and just gonna order whatever they want, and they're gonna be able to tell you, maybe not through vocalizations, but they're gonna be able to tell you. Other techniques that, and this sort of applies more generally too, is sometimes little picture cards, can be very helpful, you have to have the cards for every single possible setting, which gets a little tedious, just given how much we have phones and tablets and everything nowadays, that will be probably the best option to go about it. Still communicate with your kid, just fantastic, obviously appreciate that too. Hopefully that has been very insightful, I sort of explained what is actually going on there, well at least what we think, there's some other explanations for why that might be the case, and I will be touching up on that next time, because there's another side of the vocalization and hearing, dealing with some neurological differences found in the temporal parietal junction, specifically Bernicke's area, which deals with speech processing, and Broca's area, which deals with producing speech. So there's other findings with temporal parietal junctions as well, which are highly relevant to autism, but yeah, until then, have a good one guys.