Premium
Neuroimaging evidence of progressive neuronal loss and dysfunction in temporal lobe epilepsy
Author(s) -
Tasch Edwin,
Cendes Fernando,
Li Li Min,
Dubeau Francois,
Andermann Frederick,
Arnold Douglas L.
Publication year - 1999
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/1531-8249(199905)45:5<568::aid-ana4>3.0.co;2-p
Subject(s) - temporal lobe , epilepsy , magnetic resonance imaging , hippocampal formation , neuroscience , psychology , neuroimaging , atrophy , medicine , central nervous system disease , hippocampal sclerosis , cardiology , pathology , radiology
Whether temporal lobe epilepsy is the result of an isolated, early injury or whether there is ongoing neuronal dysfunction or loss due to seizures is often debated. We attempt to address this issue by using magnetic resonance techniques. Proton magnetic resonance spectroscopic imaging can detect and quantify focal neuronal dysfunction or loss based on reduced signals from the neuronal marker N ‐acetylaspartate (NAA), and magnetic resonance imaging (MRI)‐based measurements of hippocampal volumes (MRIvol) can quantify the amount of atrophy in this structure. We performed magnetic resonance spectroscopic imaging and MRIvol in 82 consecutive patients with medically intractable temporal lobe epilepsy to determine whether there was a correlation between seizure frequency, or type or duration of epilepsy, with NAA to creatine (Cr) values or hippocampal volumes. Volumes and spectroscopic resonance intensities were categorized as to whether they were measured from the temporal lobe ipsilateral or contralateral to the predominant electroencephalographic focus. Ipsilateral and contralateral NAA/Cr was negatively correlated with duration of epilepsy. Hippocampal volumes were negatively correlated with duration ipsilaterally but not contralaterally. Frequency of complex partial seizures was not correlated with any of the magnetic resonance measures. However, patients with frequent generalized tonic–clonic seizures had lower NAA/Cr bilaterally and smaller hippocampal volumes ipsilaterally than patients with none or rare generalized tonic–clonic seizures. The results suggest that although an early, fixed injury may cause asymmetric temporal lobe damage, generalized seizures may also cause progressive neuronal dysfunction or loss. Ann Neurol 1999;45:568–576