Fumihiro Nakamura

Characteristics of postictal headache in patients with partial epilepsy.

Migraine-like features sometimes characterize the headache that follows epileptic seizure (postictal headache, PIH). We compared patients with different types of epilepsy to investigate the association between migraine-like PIH and seizure type. Subjects comprised 364 patients with partial epilepsy. Epilepsy types were temporal lobe epilepsy (TLE, n = 177), frontal lobe epilepsy (FLE, n = 116), and occipital lobe epilepsy (OLE, n = 71). Patients participated in a structured interview pertaining to PIH as well as interictal headache and family history of migraine. Headaches were classified according to the International Headache Society criteria, which was modified for this study. Forty percent had PIH and 26% of these patients had migraine-like PIH. Migraine-like PIH occurred significantly more often in cases of TLE and OLE than in cases of FLE. In addition, the incidence of interictal migraine headache was significantly higher in patients with migraine-like PIH. These results suggest that migraine-like PIH is related to particular regions of epileptogenic focus and that susceptibility to migraine headache predisposes to migraine-like PIH.

Postictal mania versus postictal psychosis : Differences in clinical features, epileptogenic zone, and brain functional changes during postictal period

Summary:  Purpose: To clarify the differences between postictal mania (PIM) and postictal psychosis (PIP).

Effects of bright light at lunchtime on sleep of patients in a geriatric hospital I

The effects of lunchtime bright light exposure in patients of a geriatric hospital were investigated. Ten inpatients (six women and four men; mean age ± SD: 81.2 ± 8.8 years) with sleep disturbances were studied for 9 weeks. Nurses performed daily ratings for sleep–wakefulness disturbances. Approximately 8000 lx bright light exposure was performed for 3 weeks in the light therapy room. Before and after exposure, ocular function was evaluated. Clinical ratings of sleep‐wakefulness improved in eight patients. The score of difficulty in falling asleep and drowsiness in the morning declined during the light exposure. The score of drowsiness in the afternoon decreased during the post‐light exposure. Post‐exposure ocular disturbances were not found.

Multi-center study on post-ictal headache in patients with localization-related epilepsy.

Abstract The nature of post‐ictal headache (PIH) remains unclear. A multicenter study was conducted in order to evaluate frequency and risk factors for PIH. The subjects consisted of 97 patients with temporal lobe epilepsy (TLE), 65 patients with frontal lobe epilepsy (FLE) and 37 patients with occipital lobe epilepsy (OLE). The subjects were asked about PIH at each institute. Clinical factors of epilepsy were reviewed for each patient and correlated with PIH. Post‐ictal headache occurred in 41% of TLE patients, 40% of FLE patients and 59% of OLE patients. Logistic regression analysis revealed that the risk of PIH was significantly higher in OLE than in FLE. In contrast, there were no significant differences in the incidence of PIH between TLE and either OLE or FLE patients. Post‐ictal headache occurred significantly more frequently in subjects with generalized tonic–clonic seizure (GTCS) than in those without GTCS. Other clinical factors, such as sex, age, age at onset, duration of illness, seizure frequency, family history of headache and interictal headache were found to have no associations with PIH. A difference was found in the incidence of PIH depending on classification of epilepsy, but only to a relatively slight extent. It was also found that GTCS was significantly related to PIH. These results suggest that both the location of epileptogenic focus and the involvement of certain cerebral areas in the spread of seizure discharges may be closely related to PIH.

Clinical factors associated with post-ictal headache in patients with epilepsy

Objectives– To determine the incidence of post‐ictal headaches (PIH) and clinical risk factors associated with the occurrence of PIH in patients with localization‐related epilepsy. Materials and methods– The subjects were 77 patients with temporal lobe epilepsy (TLE), 34 patients with occipital lobe epilepsy (OLE), and 50 patients with frontal lobe epilepsy (FLE). The subjects were directly asked whether headaches occurred just after seizures. Medical charts were reviewed to ascertain the clinical characteristics of epilepsy in these patients. Results– The incidence of PIH was 23% for TLE, 62% for OLE, and 42% for FLE. The risk of PIH was significantly higher for OLE than for TLE or FLE, and for patients with generalized tonic–clonic seizures. Younger age at onset of epilepsy was also a risk factor for PIH. Conclusion– The occurrence of PIH may be related to the region of epileptic focus and the region of spread of epileptic discharges.

Effects of Clobazam and Its Active Metabolite on GABA-Activated Currents in Rat Cerebral Neurons in Culture

Summary: Purpose: The antiepileptic effects of clobazam, a 1,5‐benzodiazepine, have been well documented in animal experiments and clinical trials. However, the drugs mechanisms of antiepileptic actions are still undetermined. The purpose of this study was to learn how clobazam and its active metabolite modulate γ‐aminobutyric acid (GABA)‐activated currents in rat cerebral neurons in culture.

NEURAL CONNECTION BETWEEN BILATERAL BASAL TEMPORAL REGIONS: CORTICO-CORTICAL EVOKED POTENTIAL ANALYSIS IN PATIENTS WITH TEMPORAL LOBE EPILEPSY

OBJECTIVEIn patients with temporal lobe epilepsy, invasive electroencephalographic study has shown that epileptic activities arising from the unilateral temporal lobe often propagate to the contralateral temporal lobe. Which commissural pathways are responsible for this spreading remains controversial. Some previous studies, however, have suggested that interhemispheric connections between bilateral basal temporal regions (BTR) might have a significant role in propagation of epileptic activities. METHODSWe attempted to elucidate the neural connections between bilateral BTRs using the cortico-cortical evoked potential (CCEP) method. Five consecutive patients with temporal lobe epilepsy who underwent intracranial electroencephalographic monitoring were studied. RESULTSCCEP responses were recorded from a total of 24 electrodes after stimulation of the contralateral BTRs (24 CCEPs/720 recordings; 3.33%). There were 3 types of CCEP waveform: type N-P (16 of 24; 66.7%) consisting of an initial negative peak followed by a positive peak; type N (4 of 24; 16.7%) showing a negative peak only, and type P (4 of 24; 16.7%) showing a positive peak only. The latencies ranged from 48.2 to 102.3 ms (mean, 65.5 ms) for negative peaks and 70.2 to 122.0 ms (mean, 95.2 ms) for positive peaks. In all patients, the basal temporal language area was associated with at least 1 CCEP, either as a stimulated region or a recorded region (11 of 24; 45.8%). CONCLUSIONThese data indicate that there is a neural connection between bilateral BTRs. In consideration of the involvement of the basal temporal language area, we speculate that these responses may reflect some physiological connections between bilateral BTRs.

Interhemispheric connection of motor areas in humans.

Summary: We attempted to clarify functional interhemispheric connections of motor cortex (MC) by investigating cortico-cortical evoked potentials from human brains in vivo. Three patients with intractable epilepsy who underwent invasive EEG monitoring with subdural electrodes as presurgical evaluation were studied. Electric pulse stimuli were delivered in a bipolar fashion to two adjacent electrodes on and around MC. Cortico-cortical evoked potentials were recorded by averaging electrocorticograms from the contralateral hemisphere. An initial positive triphasic or an initial negative biphasic wave was recorded when the contralateral MCs were stimulated. When the non-MC electrodes were stimulated, no response was recorded. The latencies ranged from 9.2 to 23.8 ms for the initial positive peak, and 25.4 to 39.4 ms for the initial or the second negative peak. The cortico-cortical evoked potentials responses were maximal around the homonymous electrodes with the stimulated electrodes. Our results directly demonstrate the presence of the functional interhemispheric connections originating in MC. The interhemispheric transit time is indicated. The homotopic distribution of the responses indicates that motor coordination of the bilateral bodies is, at least partially, controlled within MC.

Clinical significance of ictal high frequency oscillations in medial temporal lobe epilepsy

OBJECTIVE To clarify the clinical significance of ictal high frequency oscillations (HFO) in the medial temporal lobe. METHODS This study included 19 patients who underwent intracranial electrode implantation in bilateral temporal lobes and had at least one seizure recorded at 1kHz sampling rate. The characteristics of ictal HFO in the medial temporal lobe, and the relations between the presence of HFO, pathology, and postoperative seizure outcome were analyzed. RESULTS Ictal HFO were detected from medial temporal structures in 11 patients with medial temporal lobe epilepsy (MTLE). Among eight patients without HFO, only three were diagnosed with MTLE. Ictal HFO were detected from unilateral medial temporal structures ipsilateral to the side of hippocampal sclerosis (HS). In one patient with bitemporal independent seizure onset, ictal HFO were detected only on the side of HS. HS was detected in all 11 patients with HFO, but in only one of four patients without HFO. Seizure outcome did not differ between patients with and without HFO. CONCLUSIONS Ictal HFO in the medial temporal lobe may be a specific marker for MTLE with HS. SIGNIFICANCE Recording of ictal HFO in the medial temporal lobe may be useful for presurgical evaluation of MTLE.

Uneven interhemispheric connections between left and right primary sensori-motor areas.

To clarify the characteristics of interhemispheric connections, we investigated cortico‐cortical evoked potentials (CCEP) in human. Fourteen patients with temporal lobe epilepsy who underwent invasive EEG monitoring with bilaterally implanted subdural electrodes were studied. Electric pulse stimuli were given in a bipolar fashion at two adjacent electrodes on and around the motor area (MA) or sensory area (SA), and CCEP responses were recorded by averaging electrocorticograms from the contralateral hemisphere. Seventy‐two pairs of electrodes were stimulated, and 468 recordings were analyzed. Fifty‐one of 468 recordings demonstrated CCEP responses. Of 51 responses, 16 consisted of an initial positive triphasic wave (Type 1), 27 had an initial negative biphasic wave (Type 2), and 8 showed an initial positive biphasic wave (type 3). The mean latencies of the earliest peaks were 13.1, 28.9, and 29.4 ms in Types 1, 2, and 3 responses, respectively. The responses were more frequently evoked by stimulating facial MA (f‐MA) and nonfacial MA (nf‐MA) than by stimulating SA or noneloquent area. In both f‐MA and nf‐MA stimulation, the responses were more frequently recorded at the contralateral f‐MA than at the contralateral nf‐MA or other areas. SA stimulation never evoked CCEP responses at the contralateral MA or SA. The amplitudes were maximal when f‐MA was stimulated and responses recorded at the contralateral f‐MA. These findings suggest that the interhemispheric connections are uneven. Both f‐MA and nf‐MA send dense interhemispheric connections to the contralateral f‐MA. SA may have no or only rare direct connection with the contralateral MA or SA. Hum Brain Mapp, 2012.