Hippocampal Radiation Exposure and Memory

Brief Title

Hippocampal Radiation Exposure and Memory

Official Title

Hippocampal Radiation Exposure and Memory: A Pilot Study

Brief Summary

      Neurocognitive impairment as a result of gamma knife radiosurgery has not been well studied
      and is poorly understood. Radiosurgery to the base of skull for the treatment of benign and
      malignant disorders may consequently impair memory function. There is a need to evaluate
      changes in memory function that may be associated with such exposures.

      In this pilot study, we will investigate changes in hippocampal-dependent memory function in
      10 patients receiving a low SRS dose to the hippocampus. We will also investigate such
      changes in a no-dose control group and a high-dose control group. This study will provide
      preliminary estimates of variance in memory changes associated with radiation exposure, and
      will then permit us to design future studies with the appropriate sample size justification.

Study Type



Arteriovenous Malformation

Study Arms / Comparison Groups

Description:  (Experimental group): Receiving > 2 Gy SRS to left hippocampus (n=10)


* Includes publications given by the data provider as well as publications identified by National Clinical Trials Identifier (NCT ID) in Medline.

Recruitment Information

Estimated Enrollment


Start Date

September 2007

Completion Date

December 2013

Primary Completion Date

December 2013

Eligibility Criteria

        Inclusion Criteria:

          -  Patients planned for radiosurgery for benign disorders (Groups 1&2).

          -  Patients planned for prophylactic cranial irradiation (Group 3)

        Exclusion Criteria:

          -  Previous cranial radiation

          -  Severe psychiatric disorder

          -  Severe cognitive or memory impairment (MMSE < 21)

          -  Non-English speaking, which will potentially make memory testing difficult and

          -  Other medical conditions deemed by the PI or associates to make the patient ineligible
             for protocol procedures

          -  Patients on steroid medications.

          -  Left hand dominant patients

          -  Dose exposure to left hippocampus >0.5Gy and <2Gy. We will attempt to estimate dose to
             hippocampus prior to enrollment using pre-planning on diagnostic imaging to minimize
             exclusion of patients due to dose exposure >0.5 Gy and < 2Gy following baseline memory

          -  Benzodiazepine or narcotics given on the day of radiotherapy/radiosurgery prior to
             completion of the study procedures

          -  Previous brain surgery within one year prior to radiosurgery

          -  Pregnant women




18 Years - N/A

Accepts Healthy Volunteers



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Location Countries


Location Countries


Administrative Informations



Organization ID


Responsible Party


Study Sponsor

University Health Network, Toronto

Study Sponsor

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Verification Date

June 2016