Three professors from the medicine faculty of Kuwait University took the oath on Tuesday in a brief hearing before judge Hani al-Hamdan who gave them full authority to examine the suspects.
In a written statement following the hearing, the judge said he examined two of the 37 suspects and found scars on various parts of their bodies.
The judge ordered the formation of the commission on 28 June on requests by lawyers, after having turned down similar demands four days earlier.
Many of the suspects and their lawyers insisted they were subjected to excessive physical torture in an attempt to force them to confess.
A number of the suspects took off their shirts in the opening hearing on 24 May and showed scars on their body.
The judge had referred 10 of them to the forensic department of the Interior Ministry but its report was challenged as "fake" by defence lawyers who called for an independent inquiry.
Hamdan set the next hearing for 6 September.
The defendants face charges of joining an illegal group and participating in the killing of several policemen and allegedly plotting to attack US forces and citizens in the oil-rich Gulf emirate.
The prosecution is calling for the death penalty for 34 of the suspects, including a woman, who are accused of involvement in clashes in January that left four police officers dead.
The judge said he examined two
of the suspects and found scars
Eight of the attackers were killed, while the alleged leader of the group, known as the Peninsula Lions Brigade, died in police custody.
Eight of the suspects, including the only woman, are free on bail, 19 are in jail while the remaining 10 others are still at large.
Among those freed is Shaikh Hamed al-Ali, whom a state security officer testified had issued fatwa (decrees) encouraging attacks against US troops.
His lawyer, Mubarak al-Mutawa, told the court on Tuesday that his client was being tried solely because of his opinions.