The thyroid disorder affects singing in several ways. The hypo condition causes vocal cords to swell, which in turn causes deep voice and inability to produce high notes.
The nodules in thyroid can compress the voice nerve causing partial paresis of the vocal cords resulting in hoarse voice and hiccups .Next, the goiter is adding mass to the voice box which distorts the voice. Finally the goiter can cause compression symptoms by narrowing the trachea causing a weak voice. In that particular case, singing with the head tilted back may help.
Most thyroid nodules that cause voice to change are quite large and can be detected by palpation or,
The AACE recommended thyroid neck check should help to determine if large nodules are present in the thyroid but ultrasound is the best.
I am a singer, too. They can check your vocal chords with a small mirror, no need for a scope down your nose. I have had it done both ways, my chords were fine...I have had many years of lessons, so I thought that would be the case. I had been steadily getting hoarse after about three hours of rehearsal, I would be hoarse for a couple hours, that turned into days. The connection here with the thyroid is the recurrent laryngeal nerve. It runs through the thyroid and can get squeezed by nodules. That nerve controls your vocal function. You could probably get a thyroid ultrasound for not too much, maybe $250. I had four nodules, three on the right, one on the left. I think mine were squeezing the nerve, when the right side of my thyoid came out, my singing voice was better...however, they found that I had cancer, so I had the other side removed. My last surgery was June 09 and I went back to singing and teaching that fall, with no loss of high notes, it is better and clearer. I highly suggest if you are a singer that you find a way to get an ultrasound, if there are nodules, then you will know if that could be a factor. If there are no nodules, you then know that it is not thyroid related. If you are using a lot of chest voice, you should be very careful, if you do damage the chords, there isn't much they can do. Surgery for vocal nodules most often leaves you without a singing voice permanently, so be careful.
I have thyroid nodules and my ENT had no inkling, even through 2 surgeries on my vocal cords and complaints that I felt like I had something in my throat. ENT looked down my throat about 4 times to make sure there was nothing there, but of course, he couldn't see my thyroid. Wasn't until my pcp didn't treat my hypothyroidism properly and I got sent back to ENT (after hypo dx) and explained what was happening. ENT ended up sending me for the u/s and antibody tests.
Only an ultra sound can see the A-typical cells and the formation of a nodule. Some you can feel and an ENT can provide info on if it is thyroid related if visable - but a US is always ordered to see the type of nodule it is.