NOUN: A mental condition of acute forgetfulness that affects the victim when she is engaged in a piano experience, e.g., practicing, composing, etc. The victim forgets time, forgets place, and generally becomes "swept away" by the musical experience, regardless of her talent or the quality of the music. During this state, the victim forgets that it is a work day and she is on her lunch hour and she was supposed to be back at work 45 minutes ago. The victim, instead, feels as though she is floating contentedly on a fluffy cloud of well-tempered happiness. This condition is nearly always accompanied by extended delusions of the victim's "bright future" as a concert pianist or Great Composer. The victim may suffer additional delusions of this nature, e.g., that piano and her "brilliant musical career" are more important than any dumb old, stupid old corporate job as a cubicle-dwelling software documentation specialist. Following her recovery from this delusional state (which can last from thirty minutes to several hours), the victim typically must sneak (often with great stealth) back into her company's office through a hidden basement back door--at which time the victim generally entertains vague hopes she will not get fired. In addition, it is common for the victim to suffer a dull sadness that her time with the piano has temporarily ended, and that she must exchange the piano keyboard for a computer keyboard for a seemingly endless while.
TREATMENT: Offer to be the victim's patron (i.e., rich financial supporter) so that she does not have to go to work and can stay home and continue to nurture her talent and maintain her delusional state indefinitely. If this is not feasible, it is advisable that the victim not forget her electronic timekeeping device (i.e., wristwatch) on her bedside table before leaving for work in the morning, and that said victim use said wristwatch to ensure that piano-practice sessions do not exceed the allotted lunch hour.
ETYMOLOGY: Italangreco-Janinian, from piano (lit., "the greatest instrument in the world"), key (from Middle English kai, kei) and amnesia (Gk. for "forgetfulness")
NOTE: PIANOKEYSIA is related to NINSTALGIA (neen-STAL-juh), which is a mental condition of sadness combined with fond memories. NINSTALGIA is commonly suffered by pianos whenever PIANOKEYSIA victims named Nina (my real name) snap out of their altered states and remember to go back to work.