Limbic paroxysmal magnetoencephalographic activity in 12 obsessive-compulsive disorder patients: a new diagnostic finding.
BACKGROUND
We describe frontotemporal paroxysmal rhythmic activity recorded by magnetoencephalography (MEG) in patients with obsessive-compulsive disorder (OCD).


METHODS
Twelve patients with OCD (per ICD-10 and DSM-IV criteria), aged 18 to 65 years, were assessed using MEG. Patients' classification according to the Yale Brown OCD Scale was as follows: severe = 8, moderate = 3, and mild = 1. MEG findings were compared with those of 12 age- and sex-matched healthy subjects (control group) with no previous history of psychiatric or neurologic disorders. All study participants underwent neurologic and basic medical examinations, including magnetic resonance imaging, electrocardiograms (EEGs), and electrooculograms. The study was conducted between January 2001 and January 2002.


RESULTS
Two types of MEG activity were observed in patients with OCD: (1) frontotemporal paroxysmal rhythmic activity with low-amplitude spikes (< 1 picoTesla) in 92% (11/12) of patients and (2) intermittent isolated spikes and sharp waves in all patients (12/12). The OCD group had paroxysmal rhythmic MEG activity in the cingulate cortex (12/12), insula (10/12), hippocampus (9/12), temporal superior gyrus and angular and supramarginal gyri (9/12), precentral and post-central gyri (8/12), orbitofrontal cortex (5/12), and parietal lobes (5/12). MEG recordings were normal in the control group, and EEG findings were normal in both the OCD and control groups.


CONCLUSIONS
Frontotemporal paroxysmal rhythmic activity with a preferential limbic distribution is a sensitive MEG finding in patients with OCD. Although the pathophysiology of this abnormality remains unknown, a corticostriatal network dysfunction was hypothesized.
Amo
Carlos
C
Magnetoencephalography Center Dr Pérez Modrego, Faculty of Medicine (Pabellón 8), Complutense University of Madrid, Avenida Complutense s/n, E-28040 Madrid, Spain.
Quesney
L Felipe
LF
Ortiz
Tomás
T
Maestú
Fernando
F
Fernández
Alberto
A
López-Ibor
Maria Inés
MI
López-Ibor
Juan José
JJ
D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006179:Gyrus Cinguli / Q000503:physiopathology*; D006624:Hippocampus / Q000503:physiopathology*; D006801:Humans; D008032:Limbic System / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D012815:Signal Processing, Computer-Assisted; D013702:Temporal Lobe / Q000503:physiopathology*