GABA/Glutamate Balance in Temporal Lobe Epilepsy With and Without Major Depression

Completed

Conditions studied: Epilepsy, Epilepsy, Temporal Lobe, Depression, Depressive Disorder, Major

In brief

Objective: To study the relative balance of GABA (A) binding potential and glutamate utilization in subjects with localization-related epilepsy with and without depression, subjects with major depressive disorder alone, and in subjects with generalized epilepsy (expected not to have significant comorbid depression). Pilot data shows that GABA(A) binding potential and glutamate utilization are tightly coupled in healthy subjects particularly in the mesial temporal lobe. We hypothesize that subjects with epilepsy will not exhibit the same degree of coupling, and that subjects with both epilepsy and depression will exhibit an even more pronounced decoupling. Study Population: Subjects aged 18-55 with localization-related epilepsy with and without depression, subjects with generalized epilepsy, subjects with major depressive disorder (MDD) alone, and healthy controls. Design: This is a neuroimaging study, using positron emission tomography (PET) with \[11C\]flumazenil, to measure GABA(A) binding potential, and \[18F\]fluorodeoxyglucose, to measure glucose utilization (reflective of neuronal glutamate release) Magnetic resonance spectroscopy (MRS), will be used to measure GABA and glutamate in the mesial temporal cortex, and corroborate the PET results. Structural magnetic resonance images (MRI) will be obtained for MRS localization and partial volume correction of PET images. Outcome measures: The binding potential of GABA(A), the regional rate of glucose metabolism, and the levels of GABA and glutamate as measured by MRS. Patients will be stratified by seizure type and depression ratings. ...

Key facts

Study ID: NCT00931619
Run by: National Institute of Neurological Disorders and Stroke (NINDS)
People needed: 29
Starts: 2009-06-29
Expected to finish: 2013-04-02
Last updated by the study team: 2019-12-17

Who can join

Age: 18 and older, up to 55. Sex: any. Healthy volunteers: accepted.

You may not qualify if…

Subjects with major medical or neurological disorders (besides TLE or generalized epileptiform disorder) expected to influence cerebral blood flow or morphology
Subjects with epilepsy taking any medications (other than antiepileptic drugs) that may affect cerebral blood flow, GABA or glutamate neurotransmission, or metabolism.
Subjects with epilepsy taking AED s known to exert direct effects on GABA or glutamate.
Subjects with epilepsy with depression who have taken anti-depressant drugs within 2 weeks of the study (4 weeks for fluoxetine)
Medically healthy depressed subjects who have taken any drugs, including anti-depressants, expected to influence cerebral blood flow, metabolism, or morphology within 2 weeks of the study (4 weeks for fluoxetine)
Healthy subjects who are taking any medications expected to influence cerebral blood flow, metabolism, or morphology.
Healthy subjects must be free from a personal history of seizure disorders
In order to exclude subjects at-risk for the development of a mood disorder, healthy control subjects must be free from either a personal or family history (first-degree relatives) of Axis I psychiatric disorders
Subjects with a history of drug or alcohol abuse within one year, or a lifetime history of alcohol or drug dependence (DSM-IV criteria). Subjects who consume an excessive amount of alcohol (more than 7 drinks per week for women, more than 14 drinks per week for men) will also be excluded.
Subjects with structural lesions visible on MRI, excluding mesial temporal sclerosis
Subjects with suicidal ideation, or a past history of suicide attempts
Subjects with psychotic symptoms
Subjects in whom MRI is contraindicated
Female subjects who are lactating or pregnant
Subjects with an IQ of less than 80 will be excluded from the study.

Where it is running

National Institutes of Health Clinical Center, 9000 Rockville Pike — Bethesda, Maryland, United States

Full record on ClinicalTrials.gov

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