Nocturnal paroxysmal dystonia related to a prerolandic dysplasia.

Nocturnal paroxysmal dystonia (NPD) is a rare disorder characterized by attacks of short-lived dystonic, tonic and choreoatetoid movements occurring mainly during sleep. Although seizures are believed to arise from the frontal lobe, their localization is, however, uncertain due to the lack of ictal clinical-EEG correlations. Two patients are reported with episodes clinically compatible with NPD who also experienced occasional generalized tonic-clonic seizures in which there was a frontal (prerolandic) dysplasia detected by MRI. In one patient interictal/ictal SPECTs suggested that the seizure focus was over the area of dysplasia. Both patients support the notion that NPD is a type of epilepsy arising from the frontal lobe, possibly originating in the prerolandic region.

Evaluation of algorithms for the registration of 99Tcm-HMPAO brain SPET studies.

Five functions of merit were used for the registration of 99Tcm-HMPAO brain SPET studies. The correlation coefficient (COR), the stochastic sign change (SSC), the standard deviation of ratios (SDR), the sum of the absolute differences (SAD) and a new function based on a local correlation coefficient (LOC) were tested in the registration of photic neuroactivation (ACT), epilepsy (EPL) and Wada (WAD) SPET studies. The comparison included simulated and real studies. The translation error in registration was 0.1 +/- 0.1 pixels (mean +/- S.D.) for all functions of merit for the complete set of simulated studies (10 runs for each ACT, EPL and WAD). For rotation, LOC yielded the best results with a mean error of 0.3 +/- 0.2 degree and a maximum error of 0.6 degree. Slightly higher errors were found with SAD (0.4 +/- 0.2 degree, maximum 1.0 degree) and COR (0.5 +/- 1.0 degree, maximum 1.0 degree). The highest errors were found with SDR (0.8 +/- 1.0 degree, maximum 4.8 degrees) and SSC (0.8 +/- 1.1 degrees, maximum 4.7 degrees). The results obtained from five real studies of ACT, of EPL and of WAD were in agreement with the findings from the simulated studies, thus confirming the robustness of LOC, SAD and COR for the registration of 99Tcm-HMPAO brain SPET studies.