When I was younger, one of my most favorite days was getting my Highlights Magazine, and my most favorite part was the little puzzle game where there were two pictures that were almost identical. The game was to try and find all the tiny differences between the two pictures. (Now that I am writing this, my current job makes a TON of sense. Wow.)
These clips are an excellent example of how things that seems the same can be very different between two patients. Patient #1 is relatively young and has a prior history of a CVA. You can see collection of the bolus-thin liquid-into the valleculae and pyriforms before airway closure. The patient aspirates before the swallow, with no cough response. In patient #2, we have a patient with a diagnosis of dementia, around 20 years older than patient #1. There is similar collection of the bolus, also thin, into the valleculae and pyriforms, with a similar length of time lapsed in between this collection and the closure of the airway-but no aspiration, no residues. Even though both patients have similar looking swallows, for patient #2, it can be considered a normal variance, given age, given history, given the functionality of the swallow. Patient #1 probably needs some intervention, while we should just leave patient #2 alone.
When looking at a swallow, it can sometimes be difficult to decide if what you are seeing is a normal variance, or something more problematic. Only by carefully considering the totality of the patient can you decide if the physiology that you are seeing is impaired and might need intervention and a plan of care… or if the physiology is normal for that patient. Looking at this big picture is the only way to really spot the difference.