Identifying the affected hemisphere by 1H-MR spectroscopy in patients with temporal lobe epilepsy and no pathological findings in high resolution MRI

Up to 30% of patients with temporal lobe epilepsy (TLE) remain without remarkable changes in MRI. In this study we investigated the role of (1)H-MR spectroscopy ((1)H-MRS) in lateralizing the affected hemisphere in the mentioned patient group. Twenty-two consecutive patients diagnosed with TLE were investigated by high resolution MRI and (1)H-MRS. We examined the incidence and diagnostic accuracy of temporal metabolite alterations determined by Linear Combination of Model Spectra (L C Model) via water reference. Metabolite values of each hemisphere of TLE patients were compared with healthy controls. Results of metabolite alterations were related to intensive video EEG focus localization. Reduction of N-acetylaspartate + N-acetylaspartyl-glutamate (tNAA) in the affected hemisphere revealed identification in six of nine patients (66%) with unilateral TLE. Group comparison revealed a significant reduction of tNAA (6.1+/-0.8*) in the involved temporal lobe compared with controls (6.67+/-0.4*, P=0.026). Choline levels were significantly increased in the affected hemisphere (1.42+/-0.17*) compared with healthy controls (1.22+/-0.17*, P=0.035). The results of our study show that (1)H-MRS is able to identify the affected hemisphere of MRI negative TLE patients and can be used as an additive tool in multimodal focus localization.     

Chemical shift imaging spectroscopy and memory function in temporal lobe epilepsy

PURPOSE: Hippocampal neuron loss and associated memory deficits are characteristic of intractable temporal lobe epilepsy (TLE). Proton chemical shift imaging (CSI) spectroscopy is a sensitive tool for detecting neuronal loss. The aim of this study was to investigate the correlation between memory functions and results provided by CSI spectroscopy of the hippocampal structures. METHODS: Ten patients with cryptogenic TLE participated. The study protocol involved both the acquisition of high-spatial-resolution CSI spectroscopy and neuropsychological evaluation, including memory testing and intracarotid sodium amytal test (IAT). The analysis of the CSI data was based on normative data obtained in 30 healthy volunteers. Memory functions were represented by verbal, visual, and general memory indices. RESULTS: A significant correlation was found between CSI spectroscopy of the hippocampal formation and the verbal memory indices for the dominant hemisphere. In addition, there was a significant correspondence of the qualitative judgment "hippocampal pathology indicated by CSI spectroscopy" and both "material specific memory deficit" and "memory deficit in the IAT." CONCLUSIONS: Our results demonstrate that CSI spectroscopy of the hippocampal structures is strongly related to lateralized memory deficits in patients with TLE. This suggests that CSI spectroscopy may be useful in the prediction of postoperative outcome in respect of seizure control and memory.     

Oral administration of BDNF and/or GDNF normalizes serum BDNF level in the olfactory bulbectomized rats: A proof of concept study

BackgroundNeurotrophins, especially brain-derived neurotrophic factor (BDNF) have gained significant therapeutic interest particularly in neurologic and psychiatric disorders and they have been found in human breast milk of mothers who suffered from adverse outcomes in pregnancy. This study tested the hypothesis that oral administration of BDNF/GDNF (glial cell line-derived neurotrophic factor) can exert a biological effect in a rat model of severe neuropathology induced by olfactory bulbectomy (OBX), which exhibits dysregulation of BDNF signaling and impaired blood-brain barrier.MethodsAdult male albino Sprague-Dawley rats underwent the OBX surgery and separate groups of OBX and sham-operated controls received one oral dose of vehicle, BDNF (0.005 mg/kg), GDNF (0.03 mg/kg) or their combination. One week after neurotrophin dosing the rats were sacrificed and BDNF level was assessed by ELISA in the blood serum and cerebrospinal fluid.ResultsA significant decrease of serum BDNF level was found in the OBX model. This alteration was normalized by all types of treatment BDNF, GDNF, or their combination. No influence of sham surgery or treatment was observed in the control rats. BDNF levels in cerebrospinal fluid were below detection limit.ConclusionThis study indicates that oral administration of neurotrophins is able to exert a biological effect in the OBX model. There is a number of potential mechanisms, which remain to be elucidated.