Amygdala volumetry in “imaging-negative” temporal lobe epilepsy

• Published in: Journal of neurology, neurosurgery and psychiatry Vol. 74; no. 9; pp. 1245 - 1249
• Main Authors: Bower, S P C, Vogrin, S J, Morris, K, Cox, I, Murphy, M, Kilpatrick, C J, Cook, M J
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.09.2003; BMJ; BMJ Publishing Group LTD; BMJ Group
• Subjects: Adult; Age; AMV; amygdala; Amygdala - abnormalities; Amygdala - growth & development; Amygdala - physiology; amygdala volume; amygdala volume ratio; AVR; Biological and medical sciences; Boundaries; Convulsions & seizures; Electroencephalography; Epilepsy; Epilepsy, Temporal Lobe - physiopathology; Female; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; hippocampal sclerosis; Humans; imaging-negative; magnetic resonance imaging; Male; Medical sciences; Middle Aged; MRI; Nervous system (semeiology, syndromes); Neurology; NMR; Nuclear magnetic resonance; Retrospective Studies; Studies; temporal lobe epilepsy; TLE; Tropical medicine; volumetry; Women; Human; Volumetric analysis; Nervous system diseases; Amygdala; Complex partial epilepsy; Electroencephalography; Nuclear magnetic resonance imaging; Cerebral disorder; Electrodiagnosis; Central nervous system disease; Medical imagery; Temporal lobe epilepsy; Diagnosis; Morphometry
• ISSN: 0022-3050; 1468-330X
• DOI: 10.1136/jnnp.74.9.1245

Objective: Although amygdala abnormalities are sometimes suspected in “imaging-negative” patients with video EEG confirmed unilateral focal epilepsy suggestive of temporal lobe epilepsy (TLE), amygdala asymmetry is difficult to assess visually. This study examined a group of “imaging-negative” TLE patients, estimating amygdala volumes, to determine whether cryptic amygdala lesions might be detected. Methods: Review of video EEG monitoring data yielded 11 patients with EEG lateralised TLE and normal structural imaging. Amygdala volumes were estimated in this group, in 77 patients with pathologically verified hippocampal sclerosis (HS), and in 77 controls. Results: Seven of 11 “imaging-negative” cases had both significant amygdala asymmetry and amygdala enlargement, concordant with seizure lateralisation. Although significant amygdala asymmetry occurred in 35 of 77 HS patients, it was never attributable to an abnormally large ipsilateral amygdala. Compared with patients with HS, patients with amygdala enlargement were less likely to have suffered secondarily generalised seizures (p<0.05), and had an older age of seizure onset (p<0.01). Conclusion: Abnormal amygdala enlargement is reported in seven cases of “imaging-negative” TLE. Such abnormalities are not observed in patients with HS. It is postulated that amygdala enlargement may be attributable to a developmental abnormality or low grade tumour. It is suggested that amygdala volumetry is indicated in the investigation and diagnosis of “imaging-negative” TLE.