If, during the play of a hand, dummy touches a card in the dummy hand, is that card considered to be played?
Broadly, no. The exception is if nobody noticed that the dummy played a card not indicated by declarer until each side has played to the following trick.
The relevant passages from the Laws of Duplicate Bridge
Law 45 (Card Played)
B. Play of Card from Dummy
Declarer plays a card from dummy by naming the card, after which dummy picks up the card and faces it on the table. In playing from dummy's hand declarer may, if necessary, pick up the desired card himself.
C. Card Deemed to be Played
- A card in the dummy is played if it has been deliberately touched by declarer except for the purpose either of arranging dummy's cards, or of reach a card above or below the card or cards touched.
D. Dummy Picks up a Non-designated Card
If dummy places in the played position a card that declarer did not name, the card must be withdrawn if attention is drawn to it before each side has played to the next trick, and a defender may withdraw and return to his hand a card played after the error but before attention was drawn to it; if declarer's RHO changes his play, declarer may withdraw a card he had subsequently played to that trick. (See Law 16C.)
When it is too late to change dummy's wrongly placed card (see above), the play continues normally without alteration of the cards played to this or any subsequent trick. If the wrongly placed card was the first card of the trick, then the failure to follow suit to that card may now constitute a revoke (see Laws 64A, 64B7 and 64C). If the wrongly placed card was contributed to a trick already in progress and dummy thereby has revoked, see Laws 64B3 and 64C.
F. Dummy Indicates Card
After dummy's hand is faced, dummy may not touch or indicate any card (except for purpose of arrangement) without instruction from declarer. If he does so the Director should be summoned forthwith and informed of the action. Play continues. At the end of the play the Director shall award an adjusted score if he considers dummy suggested a play to declarer and the defenders were damaged by the play suggested.