Tomokazu Nakagawa

Left anterior temporal cortex actively engages in speech perception: A direct cortical stimulation study

Recent neuroimaging studies proposed the importance of the anterior auditory pathway for speech comprehension. Its clinical significance is implicated by semantic dementia or pure word deafness. Neurodegenerative or cerebrovascular nature, however, precluded precise localization of the cortex responsible for speech perception. Electrical cortical stimulation could delineate such localization by producing transient, functional impairment. We investigated engagement of the left anterior temporal cortex in speech perception by means of direct electrical cortical stimulation. Subjects were two partial epilepsy patients, who underwent direct cortical stimulation as a part of invasive presurgical evaluations. Stimulus sites were coregistered to presurgical 3D-MRI, and then to MNI standard space for anatomical localization. Separate from the posterior temporal language area, electrical cortical stimulation revealed a well-restricted language area in the anterior part of the superior temporal sulcus and gyrus (aSTS/STG) in both patients. Auditory sentence comprehension was impaired upon electrical stimulation of aSTS/STG. In one patient, additional investigation revealed that the functional impairment was restricted to auditory sentence comprehension with preserved visual sentence comprehension and perception of music and environmental sounds. Both patients reported that they could hear the voice but not understand the sentence well (e.g., heard as a series of meaningless utterance). The standard coordinates of this restricted area at left aSTS/STG well corresponded with the coordinates of speech perception reported in neuroimaging activation studies in healthy subjects. The present combined anatomo-functional case study, for the first time, demonstrated that aSTS/STG in the language dominant hemisphere actively engages in speech perception.

Bereitschaftspotential augmentation by neuro-feedback training in Parkinson's disease

OBJECTIVE Decreased early Bereitschaftspotential (BP) is one of the electrophysiological characteristics in patients with Parkinsons disease (PD). We examined whether PD patients could increase BP amplitude by means of neuro-feedback (NFB) training for their slow cortical potentials (SCPs). METHODS We worked with 10 PD patients and 11 age-matched controls. BP was measured for self-paced button pressing by their right thumb. The subjects were instructed to make the introspective efforts to produce negative SCPs (negativation). The one-day session consisted of three trials, that is, the first BP, NFB training and the second BP, and each patient performed this routine for 2-4 days. Amplitudes of the first and second BPs were compared between the two groups that were divided depending on NFB performance. RESULTS Good NFB performance had the tendency of larger early BP in the second BP recording than in the first one, whereas in the poor NFB performance the early BP was smaller in the second BP recording than in the first one in both patient and normal groups (p < 0.001). CONCLUSIONS Good NFB performance of negativation could increase excitatory field potentials of pyramidal cells for the generation of early BP. SIGNIFICANCE Voluntary regulation of SCPs could enhance BP in PD patients and in aged controls.

Network specific change in white matter integrity in mesial temporal lobe epilepsy

OBJECTIVES To identify the specific change of white matter integrity that occurs in the brain network related to epileptic activity in patients with mesial temporal lobe epilepsy (MTLE). METHODS We recruited 18 patients with MTLE and 18 healthy subjects. In MTLE patients, the remote functional-deficit zone was delineated using fluorodeoxyglucose positron emission tomography as an extratemporal region showing glucose hypometabolism. Using diffusion magnetic resonance imaging tractography, we defined a seizure propagation tract (PT) as a white matter pathway that connects the focus with a remote functional deficit zone. We also used the corticospinal tract (CST) and inferior longitudinal fasciculus (ILF) as control tracts in the hemisphere ipsilateral to the focus. Fractional anisotropy (FA), mean diffusivity (MD), and volume of the tracts were compared among PT, CST, and ILF. RESULTS Tractographic analysis identified the uncinate fasciculus, arcuate fasciculus, and fornix as PTs. A decrease in FA was found in MTLE patients compared with healthy subjects in all tracts, but PTs showed a more significant decrease in FA than did the two control tracts. Although the change in MD was also found in MTLE patients compared with healthy controls, a tract-specific change was not observed. Although white-matter damage was observed in all candidate tracts examined, the integrity of white matter was most significantly decreased in PTs in MTLE. CONCLUSION The change in white matter integrity occurs specifically in the pathways that connect the focus and remote functional deficit zones in patients with MTLE, i.e., the pathways that are assume to be associated with seizure propagation.

Increased clinical anticipation with maternal transmission in benign adult familial myoclonus epilepsy in Japan

We recently reported clinical anticipation in Japanese families with benign adult familial myoclonus epilepsy (BAFME). However, it remains unknown whether clinical anticipation is predominantly associated with paternal or maternal transmission. We investigated the relationship between gender of the transmitting parent and clinical anticipation in nine BAFME families. Clinical anticipation regarding either cortical tremor or generalised seizures was observed in all 12 parent/child pairs (8 mother/child pairs and 4 father/child pairs). Moreover, a higher degree of clinical anticipation was associated with maternal transmission than with paternal transmission (p=0.03). Although a causative gene for BAFME still remains unknown, our finding suggests that BAFME and diseases with unstable expanding repeats, including those in non-coding regions, might share a similar molecular mechanism because such diseases often show clinical anticipation with maternal transmission.

Transient Diffusion-weighted Imaging Hyperintensity of the Cerebellar Cortex in Paraneoplastic Cerebellar Degeneration

A-53-year-old woman presented with a 2-week history of dysarthria and gait instability. On admission (day 1), a neurological examination revealed gaze-evoked nystagmus, mild dysarthria and severe truncal ataxia. Slight diffusionweighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) hyperintensity in the right cerebellar cortex were suspected on MRI (Picture). The cerebrospinal fluid (CSF) cell count was 20/μL, the protein level was 47 mg/ dL, and the cytology was negative. Anti-Yo antibodypositive paraneoplastic cerebellar degeneration (PCD) with presumed ovarian cancer was diagnosed after a thorough systemic work-up. Cerebellar symptoms progressed despite steroid pulse therapy, and MRI signal change moved to the bilateral upper portions of the cerebellum on day 21. The apparent diffusion coefficient (ADC) of the lesion was decreased in this second MRI (Picture). Although CSF findings normalized by day 29, the cerebellar symptoms progressed until paraaortic lymphadenectomy and plasma ex-

Pain in the acute phase of Guillain–Barré syndrome

Pain has not been recognized as a main feature of Guillain–Barré syndrome (GBS) in its acute phase. The pathophysiology of pain and its effect on the prognostic outcome of GBS have not been fully evaluated. The aim of the present study was to report the clinical features and prognosis of GBS patients presenting with pain in the acute phase.

Case of pneumococcal meningitis associated with pneumocephalus

A 38-year-old man was admitted to Ijinkai Takeda General Hospital, Kyoto, Japan, for disturbance of consciousness. For the preceding 2 weeks, he had had nasal discharge, headache and fever. On admission, he was poorly responsive to verbal instructions, and his neck was stiff. Head computed tomography obtained before lumbar puncture showed multiple air bubbles in the basal and pontocerebellar cisterns, and bilateral cavernous sinuses, but without any evidence of bony defect (Fig. 1). An air-fluid level was shown in the bilateral sphenoid, ethmoid, maxillary and frontal sinuses, consistent with acute sinusitis. Cerebrospinal fluid (CSF) opening pressure was 390 mmH2O, and CSF analysis showed cells 3100/lL (neutrophils 100%), protein 1100 mg/ dL and glucose 7 mg/dL, and the culture of CSF grew Streptococcus pneumoniae. The patient was treated with ceftriaxone, vancomycin and clindamycin with subsequent immediate improvement. Head computed tomography obtained on the following day showed resolution of the air bubbles. He was discharged symptom free. Although pneumocephalus results from various etiologies, bacterial meningitis associated with pneumocephalus is rare. As pneumococcus is not capable of gas production, the intracranial air in the present case might have resulted from the CSF leakage through the minute cranial defects caused by the sinusitis.

P15-5 Ictal slow shift and high frequency oscillation as revealed by intracranial wideband recording in human neocortical epilepsy

the ambiguous stimulus (e.g., human face/house) through red and green filter glasses, thus they perceived one of the two pictures at a time while the other was suppressed. Subjects were instructed to report when their dominant percept changed clearly by pressing the buttons. The numbers of button press for each category were analyzed. EEGs were recorded by a 128-ch high density EEG machine and analyzed by time-frequency analysis. “Human faces” were perceived more frequently than “monkey face” or “house”. However, the number of button press for “monkey face” and “house” were comparable. There was also no significant difference between “green” and “red” stimuli. High density EEGs revealed that gamma-band amplitudes were increased over the left fronto-temporal region when one recognized “human face” than the other categories before the button press. Our psychophysical data revealed that human face recognition could dominate over the other categories during the perception of binocular rivalry. An increase in the amplitude of the gamma-band also suggested that the presence of the neural network specific for human face perception, while the rivalrous stimulus remained to be constant by presented.

P36-12 How do voluntary movements decrease resting tremor in patients with Parkinson's disease?

Objective: In an attempt to facilitate the use of biological signals for prediction of accuracy of movement just before the onset of movement, the present study examined the relationships among MRCP parameters as physiological indices and accuracy of task performance. Methods: Experiments were conducted with following protocols; the subject touches on the center of the touch-sensible screen with the forefinger. Next, a target appears 300 pixels away from the touching points in a vertical direction on the screen. The subject moves the forefinger and touches on the center of the displayed target. This trial continued 2 sets of 50 times. MRCP data were acquired with the 128ch EEG system during experiments and the processes of voluntary motion were observed using the high-speed camera. The trigger was generated using the surface EMG on common digital extensor muscle. The data of EEG and the high-speed camera were separated into 2 groups based on the evaluation index of the accuracy. Results: Significant differences between the highand low-performance groups were clearly confirmed on the NS’s slope in MRCPs acquired from frontal region and the most notable change was showed at Fz (p < 0.05). We tried to use support vector machine (SVM) intended to classify NS’s slope into two groups without averaging. After the process of SVM, we compared two groups of NS’s slope to two performance groups that we divided performance data in each trial into newly two groups corresponding NS’s slope classified two groups by SVM. As a result, a relatively high correlation was confirmed between NS’s slope and performance. Conclusions: Based on this findings, we discuss the possibility whether it is possible to predict accuracy just before the movement is executed using MRCPs intended to use as one of the assistive method for BMI.