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Depth of Anesthesia on Implicit Memory

The Effect of Depth of Anesthesia on Implicit Memory

Status
Completed
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT00584324
Enrollment
70
Registered
2008-01-02
Start date
2006-03-01
Completion date
2012-01-01
Last updated
2026-04-07

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Anesthesia, General, Memory

Keywords

elective surgery, general anesthesia, implicit memory

Brief 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).

Interventions

COMBINATION_PRODUCTBIS 40

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.

COMBINATION_PRODUCTBIS 60

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.

Sponsors

University of Oklahoma
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
SUPPORTIVE_CARE
Masking
DOUBLE (Subject, Investigator)

Eligibility

Sex/Gender
ALL
Age
55 Years to 90 Years
Healthy volunteers
No

Inclusion criteria

* Persons signing informed consent * Elective general surgery for orthopedics (external or internal fixation) or urologic (transurethral) * Literate * Native English speaking

Exclusion criteria

* Hearing impaired * History of cognitive dysfunction * Subjects requiring post-operative sedation for any indication

Design outcomes

Primary

MeasureTime frame
To test the presence of implicit memory under two different planes of surgical general anesthesia in patients undergoing urologic (transurethral) or orthopedic (internal and external fixation) procedures3 years

Secondary

MeasureTime frame
To compare the pre and postoperative anxiety levels as a marker of clinical significance of operational implicit memory function.3

Countries

United States

Contacts

PRINCIPAL_INVESTIGATORMehmet S. Ozcan, MD

University of Oklahoma

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Apr 8, 2026