Hypotension/hypovolemia as a low-pass filter: I got cut, I went into shock, and then everything started sounding funny. I'd guess it was a 40 dB (±10) rolloff, which began near 200 Hz (±50) and left me with nothing above 1kHz. How in the world? Story, discussion of numeric estimates, off-the-cuff physiological speculations, etc...
posted by eritain to health & fitness (24 answers total) 6 users marked this as a favorite
About a week ago I had a gentlemanly disagreement with a pane of glass, which left venous blood running richly from two of my knuckles. (No winner was declared, but you should see the other guy. I totally took him.) At the first-aid station, I dropped into a typical case of shock: pallor, weakness, sweating, and thirst. I knew what it was, so I got my head between my knees and asked a bystander for water to sip. I was still feeling awful when someone got a car to drive me and my now-bandaged hands to the emergency room (where those hands would get six stitches and some iodine).
As I walked some 15 or 20 feet to the car, I experienced an unfamiliar symptom: My hearing drained out. First the high end, then the mids went very quiet. A waterfall fountain became inaudible; male voices had a very flat timbre. I could hear the bass rumble of the car engine very clearly, but not its rattling-type noises, or much road hiss/tire noise.
Note that I am pretty bad at estimating loudness, but it was a profound loss. Frequency, I'm a little better with. I understood people speaking, so I must have had some hearing up to 1000 Hz (to make out the first two vowel formants). But 700 Hz is a good estimate for the top of the road hiss that I wasn't hearing, and the loudest sounds were definitely 100-160 Hz or so.
Qualitatively, here is how much shock I was in: My vision was washed out, but not tunneled. My lips, I'm told, were colorless. I did walk 20 feet, but I'm sure I couldn't have gone 40. I had the presence of mind to keep my knees slightly bent in case I went down, and to be irritated at the people who thought that holding my elbow was really gonna help if I fainted. (Arms go limp, yo?) I did not have the presence of mind to say, 'Hold me at the shoulder, not the elbow,' or better yet, 'Wait, give me a minute here, I can't walk yet.' In the car, with a few minutes' rest and some water sipped, the normal shock symptoms receded, and the hearing loss with them.
So: What was that? Has this happened to other people? Can you propose a mechanism? (Could shock drain fluid from your cochlea, or do some fibers of the auditory nerve have a better blood supply than others, or would it more likely be the auditory cortex going under?) I welcome hypotheses, but I'm not about to go gouge myself again to test them. (Hmm, guineapigs.metafilter.com is still available.)