I've read that ms used to be checked (at least partially) with the "hot tub test." i've noticed my symptoms (dizziness, balance issues, numbness/tingling extremities) actually seem better when i'm in a hot bath/shower. mean anything or coincidence?

MS less likely but..: 60-80% of those with MS notice their symptoms significantly worsen when exposed to heat, so this makes it much less likely that you have MS, but does not totally rule it out. Many with MS-like symptoms actually have Lyme disease which is often overlooked and can be hard to diagnose. See http://www.lymeinfo.net/multiplesclerosis.html and http://www.betterhealthguy.com/lyme/testing

Coincidence: Sometimes patients with MS will worsen when subjective to sudden temperature changes. But not all patients.

RESPONSE: Yes, in the past, prior to imaging advances, "Hot Bath" test was utilized to exacerbate patient symptoms to confirm diagnosis, but no longer used as was often false positive, and MRI supplanted. Occasional MS patients seem to do better in warmer environments, and some even do worse in cold weather. Thus, your responses are not indicative of definitive diagnosis.

Hot tubs nice: Per the National Multiple Sclerosis Society the "hot tub test" was used in the past to diagnose MS. A person suspected of having MS was immersed in a hot tub of water. The appearance of neurological symptoms or their worsening was taken as evidence the person has MS. Slight elevation core body temp impairs the ability of demyelinated nerve to conduct electrical impulses. Discuss your sx with Dr.