Tsunenori Takatani

Low-voltage EEG activity presenting from psychotic stage in a patient with anti-NMDA receptor encephalitis.

EEG in anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis shows generalised or predominantly frontotemporal δ–θ activity, and epileptiform potentials are less frequent than slowness. The voltage of EEG activity in this disorder is uncertain. We studied the voltage pattern of EEG of two patients. Both patients had psychiatric symptoms, central hypoventilation requiring prolonged ventilatory support, seizures, involuntary movements and autonomic instability. No patient showed abnormal findings on conventional MRI. Mature teratoma was diagnosed in one patient after ovarian tumour resection. Both patients received corticosteroids and intravenous immunoglobulins, and plasmapheresis. One patient recovered completely. In one patient, teratoma was not found, and ventilatory support or sedative drugs were given for about 35 months. The EEG voltages in both patients were decreased in all brain areas as compared with those of the healthy controls. Low-voltage EEG activity in all brain areas was evident from the psychotic stage.

Microvascular decompression for glossopharyngeal neuralgia using intraoperative neurophysiological monitoring: Technical case report.

Background: Glossopharyngeal neuralgia (GN) is a rare functional disorder representing around 1% of cases of trigeminal neuralgia. Lancinating throat and ear pain while swallowing are the typical manifestations, and are initially treated using anticonvulsants such as carbamazepine. Medically refractory GN is treated surgically. Microvascular decompression (MVD) is reportedly effective against GN, superseding rhizotomy and tractotomy. Methods: We encountered three patients with medically refractory GN who underwent MVD using intraoperative neurophysiological monitoring (IONM). The offending vessels were the posterior inferior cerebellar arteries, which were confirmed intraoperatively via a transcondylar fossa approach to be affecting the root exit zones of the glossopharyngeal and vagus nerves. As IONM, facial motor-evoked potentials (MEPs) and brainstem auditory-evoked potentials were monitored during microsurgery in all three patients. Pharyngeal and vagal MEPs were added for two patients to avoid postoperative dysphagia. Results: GN disappeared immediately after surgery with complete preservation of hearing acuity and facial nerve function. Transient mild swallowing disturbance was observed in 1 patient without pharyngeal or vagal MEPs, whereas the remaining two patients with pharyngeal and vagal MEPs demonstrated no postoperative dysphagia. Conclusion: Although control of severe pain is expected in surgical intervention for GN, lower cranial nerves are easily damaged because of their fragility, even in MVD. IONM including pharyngeal and vagal MEPs appears very useful for avoiding postoperative sequelae during MVD for GN.

γ Heavy chain disease screening showing a discrepancy between electrophoretic and nephelometric determinations of serum γ globulin concentration

A 75-year-old woman with rheumatoid arthritis showed a discrepancy between the reduced level of serum γ globulin on cellulose acetate electrophoresis and the normal level of serum IgG determined by laser nephelometry. Although no M-peak was detectable on cellulose acetate electrophoresis, immunoelectrophoresis of the patients serum revealed a monoclonal protein reacting with anti-IgG antiserum but not with anti-κ or anti-λ light chain antiserum. Western blotting of the patients serum showed abnormal low-molecular-weight γ chains. Thus, the patient was diagnosed with γ heavy chain disease. A comparison of γ globulin levels determined by different methods may be useful when screening for this disease.

Relationship between frequency spectrum of heart rate variability and autonomic nervous activities during sleep in newborns.

INTRODUCTION We analyzed the frequency spectrum of two neonatal sleep stages, namely active sleep and quiet sleep, and the relationship between these sleep stages and autonomic nervous activity in 74 newborns and 16 adults as a comparison. METHOD Active and quiet sleep were differentiated by electroencephalogram (EEG) patterns, eye movements, and respiratory wave patterns; autonomic activity was analyzed using the RR interval of simultaneously recorded electrocardiogram (ECG) signals. Power values (LFa, absolute low frequency; HFa, absolute high frequency), LFa/HFa ratio, and the values of LFn (normalized low frequency) and HFn (normalized high frequency) were obtained. Synchronicity between the power value of HFa and the LFa/HFa ratio during active and quiet sleep was also examined by a new method of chronological demonstration of the power values of HFa and LFa/HFa. RESULTS We found that LFa, HFa and the LFa/HFa ratio during active sleep were significantly higher than those during quiet sleep in newborns; in adults, on the other hand, the LFa/HFa ratio during rapid eye movement (REM) sleep, considered as active sleep, was significantly higher than that during non-REM sleep, considered as quiet sleep, and HFa values during REM sleep were significantly lower than those during non-REM sleep. LFn during quiet sleep in newborns was significantly lower than that during active sleep. Conversely, HFn during quiet sleep was significantly higher than that during active sleep. Analysis of the four classes of gestational age groups at birth indicated that autonomic nervous activity in a few preterm newborns did not reach the level seen in full-term newborns. Furthermore, the power value of HFa and the LFa/HFa ratio exhibited reverse synchronicity. CONCLUSION These results indicate that the autonomic patterns in active and quiet sleep of newborns are different from those in REM and non-REM sleep of adults and may be develop to the autonomic patterns in adults, and that parasympathetic activity is dominant during quiet sleep as compared to active sleep from the results of LFn and HFn in newborns. In addition, in some preterm infants, delayed development of the autonomic nervous system can be determined by classifying the autonomic nervous activity pattern of sleep stages.

Psychiatric Symptoms and Electroencephalograms in Anti-NMDAR Encephalitis

The awareness of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis has been increasing throughout the world. Typically, psychiatric symptoms (PS) initially occur, followed by the development of seizures, involuntary movements, autonomic instability, or central hypoventilation.

Bite injuries caused by transcranial electrical stimulation motor-evoked potentials’ monitoring: incidence, associated factors, and clinical course

PurposeThe incidence of bite injuries associated with transcranial electrical stimulation motor-evoked potentials monitoring reportedly ranges from 0.13 to 0.19%. However, in clinical practice, bite injuries appear to occur more frequently than previously reported. Our aim was to identify the incidence of and perioperative risk factors associated with bite injuries caused by transcranial electrical stimulation motor-evoked potential monitoring.MethodsPatients who underwent elective surgery with transcranial electrical stimulation motor-evoked potential monitoring at a single tertiary hospital in Japan between June 2017 and December 2017 were included in this study. All patients were assessed by oral surgeons preoperatively and postoperatively. The associated factors with bite injuries were explored by the univariate analysis.Results12 of 186 patients experienced 13 bite injuries, including three lip, six oral mucosa, and four tongue injuries. No patient required suture repair. 11 of 12 patients had uneventful postoperative courses and were cured within 12 postoperative days. One patient with a tongue ulcer and a hematoma had difficulty in oral intake and persistent dysgeusia. Patient severe movement during transcranial electrical stimulation motor-evoked potential monitoring was associated with bite injuries (p = 0.03).ConclusionsThe incidence of bite injuries assessed by oral surgeons was 6.5% in patients with transcranial electrical stimulation motor-evoked potential monitoring, and the patients with severe movement during the monitoring tended to incur bite injuries. In rare cases, transcranial electrical stimulation motor-evoked potential monitoring may cause difficulty in oral intake and dysgeusia.

S16-2. Strategy in anesthetic management for intraoperative neuromonitoring

The development of postoperative functional dysfunction can have an impact on the length of hospital stay, total medical costs, and necessity of dependency. To maintain functional integrity, neuromonitoring including motor evoked potential (MEP), sensory evoked potential, and visual evoked potential, has been conducted during the operation. Anesthetic management is usually based on the maintenance of MEP, which is most susceptible to suppression by anesthetic agents. MEP is indicated for craniotomy, spine surgery and aortic surgery, in which the technique for stimulation and recording can vary on types of surgery. Especially, stimulus intensity and technique should be carefully applied for craniotomy. Anesthetic management remains to be challenging during MEP monitoring in aortic surgery, in which cardiopulmonary bypass with aortic occlusion and hypothermia is conducted. In pediatric cases, the selection of anesthetic agents and monitoring of anesthetic depth remained to be debated. Anesthetic fade of MEP in prolonged surgery is possible topic to be overcomed. Although the use of remifentanil and sugamadex made anesthetic management for MEP easy, patient’s movement and bite injury in response to stimulation seem to be a problem, which needs to be resolved. Safety management of multidisciplinary monitoring team is also important issue for further progress.

Post-tetanic transcranial motor evoked potentials augment the amplitude of compound muscle action potentials recorded from innervated and non-innervated muscles

BACKGROUND CONTEXT Transcranial electrical stimulation used to produce motor evoked potentials (TES-MEPs) and subsequent compound muscle action potential (CMAP) recording is widely used to monitor motor function during surgery when there is risk of damaging the spinal cord. Nonetheless, some muscles do not produce CMAP amplitudes sufficient for intraoperative monitoring. PURPOSE This study aimed to investigate the utility of tetanic stimulation at single and multiple peripheral nerve sites for augmenting CMAP amplitudes recorded from innervated and non-innervated muscles. STUDY DESIGN/SETTING A retrospective study was carried out. PATIENT SAMPLE The study sample comprised 24 patients with cervical myelopathy who underwent decompression surgery at our department between November 2005 and March 2007. OUTCOME MEASURES Compound muscle action potential amplitude was a physiological measure. METHODS We used two patterns of tetanic peripheral nerve stimulation for each patient. The first pattern consisted of tetanic stimulation of the left tibial nerve only (Pattern 1), and the second pattern consisted of tetanic stimulation of the bilateral median nerves and left tibial nerve (Pattern 2). RESULTS Compound muscle action potential amplitudes from all muscles were augmented by both tetanic stimulation patterns compared with conventional TES-MEP recording; however, Pattern 2 elicited the greatest augmentation of CMAP amplitudes, especially for CMAPs recorded from the bilateral abductor pollicis brevis muscles. CONCLUSIONS Although tetanic stimulation of a single peripheral nerve increased CMAP amplitudes recorded from both innervated and non-innervated muscles, CMAP amplitudes were best augmented when the corresponding nerve received tetanic stimulation. Additionally, tetanic stimulation of multiple nerves rather than a single nerve appears to provide better augmentation.

44. Evaluation of the results of motor evoked potentials monitoring during craniotomy

while the potentials in the long head of left biceps femoris were normal. Four months later, he developed left drop foot; NCS revealed low amplitudes in left peroneal CMAP by peroneal nerve stimulation and left sural nerve sensory action potential (SNAP). The left gluteus medius was not weak but showed denervation potentials in EMG. Presently, he showed marked muscle atrophy, sensory loss and occasional neuralgia in the left L5 and S1 segments. CMAPs and SNAPs were all absent in the left leg in NCS. Cerebrospinal fluid (CSF) analysis showed 7.0 cells/ll and elevated protein level. MRI revealed swelling in left L4–S2 nerve roots. A biopsy specimen of the left sural nerve demonstrated marked loss of myelinated and unmyelinated fibers. A left S1 nerve root biopsy specimen demonstrated T-lymphocyte infiltration within the roots and ganglia and root sheath thickening. CSF lymphocyte analysis later revealed IgH rearrangement and atypism, suggesting a diagnosis of neurolymphomatosis.