Depth of Anesthesia on Implicit Memory
Condition: Anesthesia, General; Memory
Study type: Interventional

Summary: 
      Purpose of this study is to see if different levels of anesthesia have an effect on hearing
      spoken words without awareness of having heard them or anxiety after surgery.
    

Detailed description: 
      Amnesia (lack of recall) is one of the most important goals of general anesthesia.
      Inadvertent free recall during a major surgical procedure is not only inhumane, but also
      predisposes the patient to morbidity such as post-traumatic stress disorder. Therefore, it is
      standard practice among anesthesiologists to inquire about free (explicit) recall during a
      post-anesthetic visit.

      Free recall requires a functional long term memory. Historically, lack of free recall during
      general anesthesia has been regarded as complete absence of long term memory activity.
      However, recent evidence suggests that the relationship between general anesthesia and memory
      is more complex than previously thought.

      Objectives of the proposed are twofold: (1) to test the presence of implicit memory under two
      different planes of surgical general anesthesia in elderly males (55-90 years old) during a
      uniform surgical procedure (urologic procedures via transurethral approach) (2) to compare
      the pre and postoperative anxiety levels as a marker of clinical significance of operational
      implicit memory function.

      The study is divided into three phases: pre-operative, operative, and post-operative.

      Pre-operative phase will consist of a cognitive function test (mini-mental state exam). This
      will be administered at the urology or pre-operative anesthesia clinic visit, after obtaining
      the informed consent of the patient.

      Operative phase will start with a baseline anxiety test (Spielberger state-trait anxiety
      test) just before being taken to the operating room. This will be followed by playing an
      audio file (a list of spoken words) via headphones under general anesthesia during the
      surgical procedure.

      Post-operative phase will have of a spoken word-stem completion test (just before discharge
      from the hospital) and a repeat of the anxiety test mentioned above (2 to 3 weeks
      post-operatively).
    

Intervention name(s): BIS 40; BIS 60
Intervention type(s): Combination Product; Combination Product
Intervention description(s): Mini-mental state exam: For subjects > 60, this exam will be administered pre-operatively.
Spielberger State-Trait anxiety test: Spielberger test just before being taken to the operating room.
Spoken word-stem completion test: After discharge from recovery but within 24 hrs. post surgery, this test along with the anxiety test will be administered.
Bispectral Index Monitor: The physiologic monitor is used intraoperatively to assess surgical anesthesia.
Audio File: Playing an audio file (a list of spoken words) via headphones under general anesthesia during the surgical procedure.; Mini-mental state exam: For subjects > 60, this exam will be administered pre-operatively.
Spielberger State-Trait anxiety test: Spielberger test just before being taken to the operating room.
Spoken word-stem completion test: After discharge from recovery but within 24 hrs. post surgery, this test along with the anxiety test will be administered.
Bispectral Index Monitor: The physiologic monitor is used intraoperatively to assess surgical anesthesia.
Audio File: Playing an audio file (a list of spoken words) via headphones under general anesthesia during the surgical procedure.
Other intervention name(s): Mini-mental state exam; Spielberger State-Trait anxiety test; Spoken word-stem completion test; Bispectral Index Monitor; Audio File; Mini-mental state exam; Spielberger State-Trait anxiety test; Spoken word-stem completion test; Bispectral Index Monitor; Audio File
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Supportive Care
Keywords: elective surgery; general anesthesia; implicit memory