Police have been under a lot of scrutiny this year, with many calling for reforms following the killings of George Floyd and others by officers. A new article by three Massachusetts General Hospital neurologists makes the case that there is no medical justification for the use of neck restraints like chokeholds by police officers. One of the article's authors, Dr. Altaf Saadi, spoke with GBH All Things Considered host Arun Rath. This transcript has been edited for clarity.

Arun Rath: Back in May, we saw George Floyd die when Minneapolis police officer Derrick Chauvin pressed his knee into Floyd's neck for more than eight minute. I know everybody remembers the best-known case of an officer killing a person with a chokehold, in 2014, when Eric Garner died at the hands of a New York City police officer. He'd been selling loose cigarettes. How did you and your colleagues come to be interested in looking at this specifically?

Dr. Altaf Saadi: As neurologists, we start very early on in our training hearing this adage that time is brain. What that implies to us is that even milliseconds of having interruption of blood flow to the brain can have really devastating consequences. So as neurologists, stories like Eric Garner's death and George Floyd's death, which involved having his carotid essentially compressed for eight minutes and forty-six seconds, was just really shocking to us, because we know that such a technique can be so dangerous to someone's health — and even fatal. So that really motivated us to write this piece.

Rath: Can you explain, when we're talking about chokeholds as examined in your article, specifically what kind of physical action is being taken by an officer on the subject? Talking about these two cases, George Floyd and Eric Garner, there were different physical actions taken prior to the deaths. What kind of range are we talking about?

Saadi: So the police departments distinguish between two different types of neck restraints. They refer to one as chokeholds, which involves applying pressure to restrict the airway, and then they also refer to strangle-holds, which is applying pressure to restrict the blood flow of the brain. And they differentiate this, but really we're talking about a really narrow space right in someone's neck that separates the trachea versus the carotid area. Here are these actions involved pressing or laying on a person's back to keep their face down, using an arm to restrain someone's neck, or — as was the case with George Floyd— knee-to-neck holds.

Rath: Tell us a bit more about what a chokehold physically does to an individual — the disruption of vital bodily processes, the physical trauma. What happens?

Saadi: There are a lot of negative health consequences to the brain not receiving blood and oxygen. That can include brain damage. It can include stroke, it can include seizure. It can include arrhythmia, so even potentially really fatal heart, irregular heart rhythms. And it can include tearing of the neck vessels, which can lead to stroke weeks later. So there are complications not just in the short term, but there can also be complications several weeks afterwards that would be difficult to trace as being a consequence. We know that there are both short and long-term consequences, and obviously the most devastating consequences is death. We know that these consequences are even higher if someone has conditions like coronary artery disease, for example. We know that police officers are not doing a complete assessment of someone's past medical history before applying this technique, so it really is this wide range of potential complications from this technique.

The other thing I want to mention, and that we mentioned in our article, is that interrupting the blood supply to the brain for as little as four seconds can lead to a loss of consciousness. We cite a study in our article that used cadavers to see what's the minimum amount of weight that would be required to interrupt the blood going through the carotid artery, and that was six kilograms, which is the weight of a household cat. That's (much less than) the average of an adult male, and certainly not for eight minutes and forty six seconds.

Rath: Tell us a bit about the perspective, the scientific perspective, that you're taking here. It would seem intuitive to most people that there's not a medical justification for chokeholds and neck restraints, but how are you looking at the data and employing this to come to this conclusion?

Saadi: A lot of these studies that have been published, like the one I just mentioned, weren't done in the context of studying carotid restraints used by police officers. The article that I just mentioned where they were trying to see what the minimum weight required to compress the carotid artery was just trying to advance our understanding of carotid pathophysiology. They just were using a cadaver and they were trying to understand how this works medically for us to apply to other contexts other than law enforcement. Essentially what we did is look at what had been written out there about carotid compression and made inferences from that to the context of these techniques being used in a law enforcement context. I think it's really important to point out that I'm a researcher, and so I'm always looking for data. One of the things that's really striking here is that although a lot of police departments talk about this being supposedly a safe technique to use, there's really no data transparency about police custody deaths or situations requiring use of techniques like neck restraints. So that's one of the things we called for at the very minimum — to try to have more transparency around this data.

Rath: Even though it may be obvious on a gut level to many of us, if people are making the argument that this is totally safe, you sort of need the the data there to to back it up.

Saadi: Yeah. You know, I think that for us as neurologists, it's intuitive, but I have seen quotes from police departments where they say things like, well, we're not choking anyone, we are using a carotid restraint. I think for some people, that language is very medicalized, and the use of medical lingo gives it some air of legitimacy on the surface, so a lot of people don't actually question it. I think that's what we were hoping to try to do here, because as a neurologist, I hear that and I think, why would you ever want to use a carotid restraint? That's not safe. I wouldn't trust a doctor or a nurse to perform this technique, much less a cop who's not trained as a medical professional.

Rath: For obvious reasons, we're focusing on the deaths from this. But shy of people being killed, for this kind of brain trauma, there's potentially a horrendous range of consequences for survivors, right?

Saadi: Exactly. People can have cognitive consequences years later. And as I mentioned earlier, sometimes the complications can happen several weeks later. Sometimes people can have tears or what we call dissections in the arteries just from the mechanical force that's applied, and sometimes from that people don't have strokes until weeks later. So it really is much more than the immediate consequences of what we see. Obviously what captures media attention is deaths like the tragic deaths of George Floyd and Eric Garner, but we know from the medical standpoint that there are much longer-term consequences that are probably not being captured at all because of the lack of data and transparency about the technique.

Rath: We're talking about this in the context of the police reform bill agreed to by Gov. Charlie Baker. In terms of that bill, which it looks like Baker is going to sign, are you happy with the language in it, in terms of how it addresses this? Do you think it's satisfactory?

Saadi: I think it's important to point out that the death of Eric Garner, for example, occurred in the New York Police Deparment, which had prohibited the use of chokeholds. So my emphasis here would be that it's not just a matter of prohibition, of having the language about prohibiting some of these techniques, but really following that through with enforcement and accountability. That would be my hope here in Massachusetts as well — that yes, the first step is the bill, the first step is having language around this. But from there, we need the follow-through in terms of enforcement and accountability. Again, in the context of Eric Garner, that happened in a police department that had prohibited chokeholds.