In the Star Trek fictional universe, the Emergency Medical Hologram or EMH is a holographic program intended to support or replace medical personnel aboard a Starfleet vessel or installation in case of emergency. The EMH was most commonly seen on the series Star Trek: Voyager. The program also made appearances on Star Trek: Deep Space Nine and the movie Star Trek: First Contact.

The EMH was created by Dr. Lewis Zimmerman, with assistance from Lt. Reginald Barclay. It possesses one of the Federation's most extensive medical databases, containing information from over 3,000 cultures and the personal experiences of 47 specific surgeons. The program itself is built on an adaptive heuristic matrix, pioneered by Dr. Zimmerman, which allows the EMH programs to learn and adapt quickly to new situations.

Four versions of the EMH series have been created to date, the Mark I, II, III and IV. While the status of the latter three incarnations is unknown, the Mark I programs, based on Dr. Zimmerman himself and possessing his short temper and numerous other character flaws, failed to live up to Starfleet expectations and were re-assigned to menial labour. Nicknames for the Mark I's include "Emergency Medical Hotheads" and "Extremely Marginal Housecalls".

The only Mark II to be seen was on the Voyager Episode "Message in a Bottle " aboard the USS Prometheus. The Mark II believed himself to be far superior to the Doctor, but the two had to work together to help retake the ship from Romulan captors. He is played by Andy Dick.

Only three Mark I's escaped the fate mentioned above. The EMH's of the USS Voyager and the USS Equinox, both of which were stranded in the Delta Quadrant by the Caretaker. Of these two, only Voyager's EMH, known as the Doctor or "Joe", survived. With a total run-time of approximately 10 years, he is the oldest EMH known to be in existence.

The third Mark I who escaped being re-assigned to menial labour was actually a back-up copy of the Voyager EMH. Captain Janeway had agreed to provide the Vaskans with medical supplies in exchange for dilithium crystals. The Kyrians, who were at war with the Vaskans, boarded Voyager to stop the deal, which they thought was a weapons deal of some sort. During their time on the ship, they stole a data module carrying a backup copy of the Doctor. 700 years later this module was part of a Kyrian museum exhibit which showed their version of the encounter. This biased encounter showed Voyager as a warship, crewed by a savage and sadistic crew that was willing to commit genocide. Even the Vaskan in the simulation became horrified over the atrocities committed, but the simulated Janeway told him it was too late to stop now. A curator at the museum finally figured out how to revive the holographic doctor. The Doctor was able to finally set the 700 year old record straight. Following that, the Doctor served as the surgical chancellor for the Kyrians and Vaskans for many years. Eventually he took a ship and departed for Earth — he felt a strong need to go home.

While spending some time in the 20th century, Voyager's EMH received a mobile emitter, a piece of 29th century technology that allows him to move freely anywhere.

His character's growth and gradual humanisation throughout Star Trek: Voyager provided one of the more compelling arcs in the series, eventually repeated with Seven of Nine in later seasons.

The Doctor created the ECH, or Emergency Command Hologram, during one of his many fantasies. This was once used when the Doctor took over Voyager when the Captain couldn't command.

Dr. Zimmerman has also been involved in a project to create a longer-running version of the EMH, the Long-term Medical Hologram. The status of this project is unknown following the discovery that Dr. Julian Bashir, the man selected to be the template for the LMH, was genetically enhanced.

See also

• Expert system

External links