Yes, there is a woman who claims she can smell Parkinson's and yes, in a pilot study her abilities convinced scientists who started further research.
However, from the (so far) available data it is hard to tell, whether she really has the abilities or not.
Very interesting topic, but not easy to answer.
Here are my current findings.
Yes, it's possible.
Generalized anxiety disorder can make you sweat more:
Physical symptoms of GAD
GAD can also have a number of physical symptoms, including:
a noticeably strong, fast or irregular heartbeat (palpitations)
muscle aches and tension
trembling or shaking
shortness of ...
The phenomenon is real, but the first explanation is wrong. For an account of what happens, help yourself to a very good answer at the Seasoned Advice StackExchange.
Basically, there are various droplets in scotch that take up or release molecules relevant to taste and odour, depending on the alcohol concentration in the surrounding liquid. This is a ...
It is true - the process is called habituation. It depends on how frequent (odor exposure [or sniffs] per minute) a smell is registered. Habituation can last from less than ten minutes up to at least 30 minutes (Chaudhury et al., 2010). As mentioned in the link, different parts of the olfactory system appear to be involved, but it is mainly explained through ...