In focal ictogenesis, gamma oscillations (30–70 Hz) recorded by electroencephalography (EEG) are related to the epileptiform synchronization of interneurons that links the seizure onset zone (SOZ) to the surrounding epileptogenic zone. We hypothesized that the synchronization of interneurons could be detected as changes in the regularity of gamma oscillation rhythmicity. We used multiscale entropy (MSE) analysis, which can quantify the regularity of EEG rhythmicity, to investigate how the regularity of gamma oscillations changes over the course of a seizure event. We analyzed intracranial EEG data from 13 pediatric patients with focal cortical dysplasia. The MSE analysis revealed the following characteristic changes of MSE score (gamma oscillations): (1) during the interictal periods, the lowest MSE score (the most regular gamma oscillations) was always found in the SOZ; (2) during the preictal periods, the SOZ became more similar to the epileptogenic zone as the MSE score increased in the SOZ (gamma oscillations became less regular in the SOZ); and (3) during the ictal periods, a decreasing MSE score (highly regular gamma oscillations) propagated over the epileptogenic zone. These spatiotemporal changes in regularity of gamma oscillations constitute an important demonstration that focal ictogenesis is caused by dynamic changes in interneuron synchronization.

Object: The purpose of this paper is to report on the authors' advanced presurgical interactive virtual simulation technique using a 3D computer graphics model for microvascular decompression (MVD) surgery. Methods: The authors performed interactive virtual simulation prior to surgery in 26 patients with trigeminal neuralgia or hemifacial spasm. The 3D computer graphics models for interactive virtual simulation were composed of the brainstem, cerebellum, cranial nerves, vessels, and skull individually created by the image analysis, including segmentation, surface rendering, and data fusion for data collected by 3-T MRI and 64-row multidetector CT systems. Interactive virtual simulation was performed by employing novel computer-aided design software with manipulation of a haptic device to imitate the surgical procedures of bone drilling and retraction of the cerebellum. The findings were compared with intraoperative findings. Results: In all patients, interactive virtual simulation provided detailed and realistic surgical perspectives, of sufficient quality, representing the lateral suboccipital route. The causes of trigeminal neuralgia or hemifacial spasm determined by observing 3D computer graphics models were concordant with those identified intraoperatively in 25 (96%) of 26 patients, which was a significantly higher rate than the 73% concordance rate (concordance in 19 of 26 patients) obtained by review of 2D images only (p < 0.05). Surgeons evaluated interactive virtual simulation as having “prominent” utility for carrying out the entire surgical procedure in 50% of cases. It was evaluated as moderately useful or “supportive” in the other 50% of cases. There were no cases in which it was evaluated as having no utility. The utilities of interactive virtual simulation were associated with atypical or complex forms of neurovascular compression and structural restrictions in the surgical window. Finally, MVD procedures were performed as simulated in 23 (88%) of the 26 patients . Conclusions: Our interactive virtual simulation using a 3D computer graphics model provided a realistic environment for performing virtual simulations prior to MVD surgery and enabled us to ascertain complex microsurgical anatomy.

To determine whether the monitoring of abnormal muscle response (AMR) and facial motor evoked potential (FMEP) during microvascular decompression (MVD) for hemifacial spasm (HFS) might be useful for predicting the postoperative clinical course and final outcomes. We analyzed 45 HFS patients who underwent both AMR and FMEP monitoring during MVD. Patients were divided into two groups on the basis of post-MVD disappearance (group AMR-A) or persistence (group AMR-B) of AMR. With regard to FMEPs, patients were classified into one of the two groups according to the ratio of the final to baseline FMEP amplitudes recorded for the orbicularis oculi muscle: one group with a ratio of <50% (group FMEP-A), and the other with a ratio of ≥50% (group FMEP-B). Twenty-one of the 26 (81%) patients in group AMR-A were assigned to group FMEP-A, whereas 9 of the 17 (53%) patients in group AMR-B were assigned to FMEP-B (P < 0.05). In 38 of the 40 (95%) patients in whom the AMRs disappeared or persisted at amplitudes <50% that at the baseline, HFS had subsided at the final follow-up. Forty of the 42 (95%) patients whose FMEP amplitude ratios indicated reduction in the amplitudes from the baseline, had complete relief of the symptoms. Nineteen of the 20 (95%) patients whose AMRs disappeared after MVD experienced immediate relief of their symptoms after the operation. With regard to 14 of the 20 (70%) patients whose AMRs persisted at the final recordings, the symptoms of HFS improved over time and eventually subsided (P < 0.001). Intraoperative monitoring of both AMR and FMEP during MVD may be useful in predicting the postoperative outcomes in HFS patients. The AMR-related findings may help to predict whether HFS disappears immediately after surgery or some time later.

Lavender essential oil (LEO) was reported to improve sleep quality. We investigated the influence of aromatherapy by testing the effects of LEO on stress responses during a short-duration sleep in a single-blind, randomized, crossover trial. The subjects were twelve healthy adults who were nonsmokers without any known disease and who were not prescribed medications, and nine of these completed the study. After the subjects had fallen asleep, they were sprayed with LEO using an aroma diffuser. Before and after 90 min of sleep, α-amylase, chromogranin A (CgA), and cortisol levels in saliva were measured as objective stress indicators, and the Japanese version of the UWIST Mood Adjective Checklist was used as a subjective indicator. A comparison of changes before and after sleep, with and without LEO, revealed that the cortisol level did not significantly change; however, α-amylase (p < 0.05) and CgA (p < 0.01) levels significantly decreased after LEO inhalation. A mood test indicated no change in mood before and after sleep, with or without LEO. Since α-amylase and CgA reflect the sympathetic nervous system response, these results indicate that LEO aromatherapy during a short-duration sleep cycle suppresses the stress response, especially that of the sympathetic nervous system.