Fal-tor-voh

Fal-tor-voh is the name of a Vulcan treatment used for those sufferers of a neurological imbalance that can only be cured through the use of a Vulcan mindmeld.

The disease itself causes the neuropeptide levels in the brain to decrease and effects the Vulcan's ability to maintain their logical control. Fal-tor-voh requires a mindmeld with a compatible patient which usually means a blood relative.

Tuvok suffered from the disease in 2378 which required him to take treatment as he was beginning to show signs of a lack of control and displays of emotion. However, none of the Vulcans on the ship were compatible which required him to reach the Alpha Quadrant in order to find a relative that could perform the fal-tor-voh treatment. (VOY episode: Endgame)