This is very interesting! It is the first treatment ever for PseuodBulbar Effect (aka emotional lability) - this afflicts 4-6 million people and can be very disabling as it makes one react in socially taboo ways (laughing uncontrollably at a funeral, for example). It is prevalent in MS and ALS but can occur in PWP.

Even more interesting is the treatment. It's the same cough syrup used by White Rats here with the addition of Quinidine to greatly extend metabolism of the DXM. I think this sends a strong message that yes, we can find new uses for OTC drugs, market, and sell it. Will DXM neuroprotection for PD be far behind?

Medscape report

AAN News