Thiamine is highly effective with all the symptoms, both motor and non-motor.

[Gcf51]

I am sure I am not the first to post this summary of Dr. Antonio Costantini Work. hormonesmatter.com/high-dos...

There is even a quote from it in Dap1948 's book.

"The use of a vitamin in megadoses to treat disease is brand new. It seems that enough clinical evidence of its benign, non-toxic effect has been reported by this Italian group to “set the world of medicine on fire”. The concept of using a molecule, essential to life, in large doses as a drug will undoubtedly require further confirmation, but it would be absurd to ignore these results."

The whole article is worth quoting but I like:

“The effectiveness of one intramuscular injection of 100 mg is nothing short of impressive in all cases they have observed. It determines an almost sudden improvement, clearly appreciable by the doctor as well as by the patient. The tremor, one of the major symptoms in this disease, is strikingly reduced.”

[jocelyng]

many, many posts on the effectiveness of B1. I am among the devotees.