We at Hyfe, Inc., are a company devoted to working on tools to better understand the importance of cough. It is Hyfe’s intention in the future to seek regulatory approval for medical products that analyze cough in order that they may be used to diagnose, monitor, and facilitate better treatment of respiratory illnesses.
Reid Moorsmith: Dr. Slovarp, thank you for agreeing to this Q&A! To start, can you tell us where you work, what your current position is, and what’s the focus of your clinical research and practice?
Dr. Laurie Slovarp: I’m an associate professor at the University of Montana in the School of Speech, Language, Hearing, and Occupational sciences. I’m also the director of the VOICES Lab, which is Voice Outcomes and the Inquiry of Cough and Essentials in Swallowing. At this point, my research is solely about chronic refractory cough with a particular focus on Behavioral Cough Suppression Therapy, or BCST.
RM: What is BCST?
Dr. LS: The first step in Behavioral Cough Suppression Therapy is education. We’re helping patients understand cough hypersensitivity and the rationale for cough suppression therapy. The cough reflex is very plastic, it changes a lot depending on viral infections and things we’re exposed to. We help patients understand that suppressing the urge to cough triggers our body to calm down and not be so sensitive.
The second part is teaching them different breathing-type cough suppression strategies. I always tell my patients, the idea of these strategies is to work all of the parts that you use to cough, but to make them do something different - often the exact opposite. When we cough, we contract our abdominal muscles really abruptly. To suppress a cough we do a really long exhale, we contract those muscles really slowly and gradually.
Then we send our patient home and say - we want you to practice these breathing strategies multiple times a day. This is for two reasons, I want them to get good at it and I want them to know exactly what they need to do when a need arises. But the other thing is, I want them to establish a strong motor pattern because every type of sequential motor act that we do is ingrained in our nervous system. The more you do it, the more ingrained it is. This makes it more able to override your very ingrained cough response. Then we ask them to also do it at the first sign that they might feel an urge to cough or if they're about to enter a situation that they think will be cough-provoking, like walking down the soap aisle at the grocery store or going out into the cold.
Then they come back, we see how they're doing. Sometimes these patients only need one or two sessions. Others need a few more sessions because they're just so severe, they're struggling to reliably suppress the cough. In such sessions, if we can reliably trigger the cough, like exposing them to perfume, I'll do that in my therapy session. We'll just coach them through it - get ready, here it comes, now breathe through it. We make sure they can suppress it. Sometimes that was really helpful for them because they think they can't do it. But then with some coaching, they realize they can. They're usually surprised that eventually, the urge to cough went down.
Some patients have concomitant muscle tension dysphonia, which is a voice problem where they're having some strained vocal quality. About 40% of the patients with chronic refractory cough have this muscle tension dysphonia and a lot of them don't even know they have it. They just have gotten used to talking like this, and it's just accepted, but it's not normal and it's irritating to the voicebox.
RM: How often does behavioral cough suppression therapy actually work?
Dr. LS: The research tells us 70 to 88% of the time. Now, that doesn't mean that all of those patients are completely cured. But in the research that I have done, 55% or more patients reported they were quite satisfied. I didn't ask if that satisfaction is enough so that they're not going to seek any more treatment, but my hunch is that it is. The majority of the people that come to see me, well over 50%, are thrilled with the progress they've made. And a lot of times they're thrilled because they've already been to like five doctors, and they've been dealing with this cough for years and years. So even a marginal improvement is a drastic improvement in their quality of life.
RM: What makes BCST interesting among therapies for respiratory conditions?
Dr. LS: We spend a lot of time talking about cough triggers and trying to intervene at the moment just before the cough. If you really start to get them to pay attention, they'll be able to identify something. In our patients, it’s almost always something that they feel in their throat. A lot of people describe it as a tickler itch that's pretty obvious for them. Sometimes it's just a little bit of a tightening that they'll feel, or they might notice a change in their breathing. I do see a lot of patients who say they don't know what's coming. But then as we're talking, they're in mid-sentence, and I can tell that they are very clearly trying not to cough so that they can get their sentence out. Then it's a matter of pointing out - see, you don't have to be able to tell me what it is that you're feeling but you do know a cough is coming.
RM: Gastro-esophageal reflux disease (GERD) is a common cause of cough. One that can sometimes be addressed with behavioral change. Can you talk about how BCST works with GERD you would say to someone with persistent cough that GERD may be contributing to?
Dr. LS: I always ask about symptoms of GERD. If they have symptoms and are not on a medication for it, I give them some education about GERD meds and encourage them to speak to their doctor about it. I also often recommend an alginate and behavioral modifications to minimize GERD (e.g., don’t eat 2-3 hours before going to bed, sleep on an incline, avoid certain foods and alcohol, etc.). If they are on a reflux med, particularly a PPI (proton pump inhibitor such as omeprazole), I ask them when they take it. I find LOTS of people don’t know how to properly take PPIs - which is 30 minutes before a meal. If they are on a med and are still experiencing reflux symptoms, I strongly recommend alginate (I don’t think I’ve ever come across a patient who has ever heard of this type of treatment) and also encourage them to speak to their doctor because they might need to change how they are treating it.
If they are on a reflux med that was prescribed for their cough, I ask them if they had reflux symptoms prior to going on the med and if the med changed their cough. If the answer is no to both of those questions, I strongly encourage them to speak to their doctor about stopping whatever med they are on. The cough guidelines don’t recommend putting someone on a reflux med for cough unless they have overt symptoms of GERD, but I find these guidelines are rarely followed and just about every patient I see was prescribed either an H2 blocker (such as Pepcid) or PPI in case their cough was due to GERD. This is often not followed up on by the doctor and then people stay on it indefinitely.
I also tell people, if your GERD is not managed, behavioral cough suppression therapy can help with symptom control but the GERD may contribute to persistence of hypersensitivity. So, they need to work hard to get their GERD under control.
RM: Do you think knowing how closely connected cough is to mealtimes would help with the diagnostic process?
Dr. LS: My hunch is that coughing during meals is not an indication of reflux but more of general laryngeal irritation (hypersensitivity) but cough within a certain time period after meals may be more associated with reflux.
RM: Someone who hasn't had success dealing with their cough, how do they find a cough behavioral therapist?
Dr. LS: Yeah, that's a good question. The best place to find a therapist that knows how to do this research is to find one that works closely with an ear, nose, and throat doctor. Because there's such an overlap between upper airway disorders and voice problems, and with cough patients, those types of therapists that specialize in voice are likely to know how to deal with this condition. I randomly get emails from people across the country and I just got one this morning from somebody in Miami who came across my name. Luckily, I was able to find somebody for her right away, because I know to look for ENT offices and see if they have a speech pathologist, and generally speaking, they will have worked with cough. It's a lot harder for people that live in rural areas, because there are not that many therapists that can specialize in there because they won't stay busy.
RM: Why does cough tracking matter?
Dr. LS: For me as a therapist, it’s relevant to understand the behaviors that are contributing to triggering a cough that my patients may not be aware of. We can then capitalize on maybe not even so much to avoid those things but to help prepare for them.
RM: Okay, let’s talk more generally about cough monitoring. So how have people tracked and monitored their cough in the past?
Dr. LS: I've tried to get people to write it down. Doesn't work. People don't want to do that. Even if I say to answer three questions at the end of the day. Invariably, they won't do it. So I don't think anybody's had a good way to monitor their cough. They just kind of subjectively monitor it like, oh, this was a pretty good day or this was a bad day.
RM: Is there now a better way to track cough?
Dr. LS: Yes, I actually have recommended [CoughTracker] occasionally for patients. And I remember one particular patient for whom it was actually pretty helpful because this patient didn't really think that drinking alcohol was related to his cough. Then he came back after abstaining for a week. And then on that Friday, he started drinking again, and there was a huge uptick in his coughing over the weekend. So I think that there's a lot of room where that's going to be helpful.
RM: I'm seeing a kind of typology. There are things that are just part of life that one can’t avoid, like the weather. Then there are things in the middle category that are more voluntary, like changing a soap or shampoo or getting a partner to not wear perfume. And then there are things that are voluntary, like smoking or coffee, which are less subject to change. Do you see BCST playing a different role in each of these categories?
Dr. LS: So much, actually. We definitely talk to a lot of people about what they do during their day, and what helped contribute to their triggers. Unless it's something that I know is really harmful for them, my treatment approach is not avoidance at all. In fact, I do the opposite. If they can successfully suppress it, I encourage them to trigger an urge to cough that they then can suppress. The data seems to indicate that that is what contributes to a change in sensitivity. But the monitoring can be helpful because then they know when to kind of prep for that, and what kind of a situation or scenario is going to contribute to it. There are some things like maybe if alcohol does contribute, or caffeine, they know they're going to a wedding today or whatever. So they are going to avoid the day before so that it’s less likely they’ll have a problem
RM: In addition to the projects you already have going on, what's on your wishlist?
Dr. LS: If finances were not an issue, I would have a functional MRI machine. And I would look at changes in the brain after BCST.
RM: Interesting! What would your hypothesis be?
Dr. LS: So there's some really cool work by Stuart Mazzone, and he's done a ton of functional MRI work. And we know that patients with chronic refractory cough have higher levels of activity in the midbrain than people who do not have it. So there's something going on there. They also have lower levels of activation in networks that we know are involved in cough suppression. So my theory is that after behavioral therapy those areas that we know are linked to cough suppression will light up more - they're going to be more active. I think we're strengthening those cough suppression networks…. I think there's so much room for opening the door for more on behavioral management for a range of health issues.
Our thanks to Reid Moorsmith and dr. Laurie Slovarp for their contribution to this article.