Disorientation is a very common computer or opponent imposed disability, but it is an umbrella term for a variety of disabilities.
In role playing games like D&D and Final Fantasy, poisons and spells are employed that are often visually represented by a purple or green mist over the affected character's head and a silly looking, looping movement of some sort. The affect on gameplay in RPGs covers a wide variety, in EarthBound if Ness or one of his allies becomes 'confused'. his or her attacks will often be misdirected, occasionally hitting his or her allies or his or herself! Another example of disorientation from Earthbound comes in the form of the mushrooms that can grow on one's head when fighting the Walking Mushrooms. If Ness is afflicted by this, his movement in the overworld will change. Left will become up, right will become left, weird things happen to your direction-finding abilities. This is a common form of disorientation.
Another popular form of disorientation, especially in the recent history of video games is onscreen effects. Yoshi's Island's 'Touch Fuzzy, Get Dizzy' level is a popular one because of the hilarious impact it has on Yoshi's sprite (he will stumble around as though drunk, but his pupils will dilate and whirl around inside his eyeballs) and the ground. Flat land will undulate and what was once flat will become steep and then a divot and back again, fluidly; this affect is a subtle but remarkable technological achievement for the time. In Grand Theft Auto Vice City, San Andreas, and IV, on the other hand players can drink alcohol or smoke cannibis (in one instance solely in San Andreas, and it's second hand, thanks to Peter Fonda's paranoia) and the screen gets wavy, and it becomes difficult to control your character, especially drive. Linking the two games in disorientation is DMA Design's Uniracers (or Unirally in the stranger territories) featured an evil unicycle, the Anti-Uni, who did not appear until the final grand prix, Hunter. Anti-Uni would cast spells that covered the spectrum of disorientation from Barf mode which would make the game's background move out of sync with the foreground, Hedgehog mode (a jab at Sega) which would slow everything down to a crawl, Reverse mode which made left right and right left was easily the most frustrating, in a side-scrolling racing game.
In multiplayer games, players can use items to disorient their opponents. Control reversal, screen-wackiness, pixelation, ink blots; the list goes on and on for different forms of disorientation.