M Risinger | PubMed Health

PubMed2001

Neuronavigational epilepsy focus mapping.

The localization of a seizure focus for resective surgery often requires invasive monitoring for precise localization of the target as well as structures to avoid. We report on the use of intra-operative surgical navigation to precisely localize and co-register subdural electrodes to regions of know radiographic pathology. Additionally, the navigation system was used to develop intra-operative electrode maps. These maps were subsequently used in the sub-acute recording phase to assign electrographic pathology and function (e.g. speech) to a specific cortical surface anatomy. This permitted for more precise planning of surgery and better assessment of potential risk, based on functional as well as anatomical criterion.

Artificial Intelligence↗

PubMed1995

A point mutation in the protein 4.2 gene (allele 4.2 Tozeur) associated with hereditary haemolytic anaemia.

A recessively transmitted haemolytic anaemia associated with the lack of protein 4.2 was found in a Tunisian kindred. Trace amounts of this protein (72 kD component) became visible using high-sensitivity Western blots. Band 3 and ankyrin genes were excluded as candidate genes by linkage studies, and nucleotide sequencing of band 3 cytoplasmic domain cDNA revealed no alteration. In contrast, protein 4.2 gene contained in the homozygous state a mutation at position 310: CGA-->CAA (Arg-->Gln). This mutation defining allele 4.2 Tozeur was co-inherited with the disease. The mRNA encoding the variant protein was normal in size and approximately normal in amount. Recombinant protein 4.2 Tozeur bound normally to red cell IOVs but disclosed an increased susceptibility to proteolysis in vitro. We infer that the nearly total absence of protein 4.2 in the patients results from imbalance between destruction and synthesis of mutated protein 4.2 prior to its binding to the membrane.

Anemia, Hemolytic↗

PubMed1988

Computer enhancement of scalp-sphenoidal ictal EEG in patients with complex partial seizures.

Color topographic maps of scalp/sphenoidal ictal EEG records were computer-generated in 5 patients with medically refractory complex partial seizures of suspected temporal lobe origin. Seven ictal EEG records were analyzed by parsing them into a series of 1.28 sec epochs. User-interactive, computer techniques were utilized to replace eye movement and other artifactual segments in the peri-ictal records with nearby uncontaminated EEG segments. Artifact replacement techniques were designed to minimize or eliminate EEG discontinuities in those epochs in which artifact was removed. Significance probability maps consisting of z scores were constructed by comparing theta band power for each 1.28 sec epoch composing the peri-ictal period with the mean and standard deviation of theta power computed from a pre-ictal baseline period consisting of 50-75 epochs. The resulting maps were compared with available independent clinical measures in order to validate their usefulness. The independent measures consisted of non-invasive data (visual impressions of raw scalp/sphenoidal ictal EEGs and positron emission tomography) and invasive data (depth ictal recordings, pathological findings in resected temporal lobes, and surgical outcome). Ictal topographic maps appeared to either confirm or provide new localizing information in all 5 patients. In 3 of 5 patients, several seconds of localized theta suppression preceded localized theta augmentation during the peri-ictal period. The transition between the 2 states was very rapid (approximately 2 sec). The spatial locus of suppression was always in agreement with the spatial locus of augmentation. In general, the maps were considerably easier to interpret than the raw scalp/sphenoidal ictal EEGs: (1) Localized theta suppression in the maps was not evident from visual inspection of the raw ictal scalp/sphenoidal EEG. (2) Clear localized theta augmentation in the maps occurred well before the appearance of unambiguous phase reversals in the raw scalp/sphenoidal ictal EEG. (3) Mapping data were correctly lateralizing in 1 patient in whom visual interpretation of the raw scalp/sphenoidal ictal EEGs was considered non-localizing but often suggestive of a seizure origin in the hemisphere contralateral to that implicated by depth recordings, PET, and pathological data. These results suggest that topographic mapping of scalp/sphenoidal ictal EEGs in patients with complex partial seizures may eventually prove to be a useful adjunct to the interpretation of raw ictal recordings.

Brain↗