Cognitive Dysfunctions in Patients With Severe Obstructive Sleep Apnea Syndrome: Neuropsychological Test and Event-Related Potential Study

Background: Patients with obstructive sleep apnea syndrome (OSAS) show variety of dysfunctions in cognitions including general cognitive function, attention, and frontal lobe and executive function. However, there is no consensus on the main features of the cognitive dysfunction in OSAS patients. So we performed neuropsychological tests and event-related potential (ERP) studies in patients with severe OSAS to evaluate the cognitive dysfunctions and changes of auditory and visual P300. Methods: Twenty-eight men with severe OSAS (apnea hypopnea index (AHI)=63.1±}17.8/hr) and 16 age, sex, educationmatched normal controls (AHI=2.9±}1.8/hr) underwent neuropsychological tests and ERP studies. Results: Patients with severe OSAS showed deficits in corsi block forward and backward test during neuropsychological evaluation, and delayed latency and decreased amplitude of auditory P300. There were significant correlations between auditory P300 amplitudes and digit span forward or corsi block forward test scores, and between visual P300 amplitudes and digit symbol test scores. Conclusions: These findings suggest that severe OSAS patients may have deficits in attention and short-term memory, and abnormal auditory P300.OAIID:oai:osos.snu.ac.kr:snu2008-01/102/2014017262/5SEQ:5PERF_CD:SNU2008-01EVAL_ITEM_CD:102USER_ID:2014017262ADJUST_YN:NEMP_ID:A079623DEPT_CD:801CITE_RATE:0DEPT_NM:의학과SCOPUS_YN:NCONFIRM:

Cortical Representation to Odorant Stimulation: Statistical Non-parametric Mapping of Low Resolution Electromagnetic Tomography (LORETA)

Background: Although olfactory stimulation has been known to produce effects on human mood and cognition, the specific EEG patterns of activity was reported diversely. The purpose of this study was to investigate EEG changes by odorant using low resolution electromagnetic tomography (LORETA) in young healthy subjects. Methods: The EEG's of nineteen (10 males, 9 females) non-smoking right-handed college students were recorded after odorant stimulation. A nineteen-channel EEG was recorded referenced to linked ears before and during olfactory stimulation. Olfactory stimulation was presented with lavender essential oil by blotter method. The LORETA power was computed from ten 2-s epochs, separately for the different EEG frequencies. The power values were logarithmically transformed and paired sample t-tests were done for each voxel and frequency band (1.5-30 Hz). Statistical results were displayed 3-dimensionally on the standard brain template. Results: All subjects experienced positive feelings (relaxed and pleasant) by olfactory stimulation with lavender oil (p<0.01). The LORETA power of theta and alpha band was increased in the dorsolateral and medial frontal areas, predominantly in the posterior cingulate gyri. The alpha LORETA power was also increased in bilateral orbitofrontal regions and the left perisylvian region including the insular cortex. Beta power was increased in the posterior cingulated gyri and mesial temporal region, predominantly on the left side. Conclusions: These results suggest that olfaction associated with emotional feeling might induce brain electrical power changes not only in the limbic system but also in the neocortex with lateralization to the dominant hemisphere.OAIID:oai:osos.snu.ac.kr:snu2004-01/102/2014017262/1SEQ:1PERF_CD:SNU2004-01EVAL_ITEM_CD:102USER_ID:2014017262ADJUST_YN:NEMP_ID:A079623DEPT_CD:801CITE_RATE:0DEPT_NM:의학과SCOPUS_YN:NCONFIRM:

Ictal Hyperperfusion of Brain Structures Related to Ictal Dystonic Posturing in Temporal Lobe Seizures

Although dystonic posturing (DP) during temporal lobe seizures is known to be related to basal ganglia activation, the mechanism of the dystonic posturing has not been investigated in greater details . Methods: Thirty-two patients with mesial temporal lobe epilepsy (TLE) underwent ictal and interictal SPECTs. They were classified into two groups: 1) DP with ictal dystonia during ictal SPECT (N=15) and 2) Non-DP without dystonia (N=17). Ictal-interictal SPECT subtraction was performed as follows: co-registration, intensity normalization, subtraction, thresholding and then an overlay to SPGR MRI. The presence and intensity of ictal hyperperfusion were determined in frontal lobe, basal ganglia, temporal lobe and insular cortex. Results: The incidences of ictal hyperperfusion in DP vs. Non-DP were caudate nucleus [80.0%(12/15 patients) vs. 0% (0/17), p=0.001], putamen [93.3% (14/15) vs. 48.2% (8/17), p=0.005], globus pallidus [53.3% (8/15) vs. 23.5% (4/17), p=0.082], thalamus [80.0% (12/15) vs. 41.2% (7/17), p=0.026], insular cortex [46.7% (7/15) vs.23.5% (4/17), p=0.051], orbitofrontal [46.7% (6/15) vs. 35.3% (7/17), p=0.053], medial frontal [6.7% (1/15) vs. 18.7% (2/17), p=0.621], dorsolateral frontal [13.3% (2/15) vs. 18.7%(2/17), p=0.737] in the hemisphere of epileptic side. In patients who showed ictal hyperperfusion in striatum and thalamus, the average intensity of hyperperfusion in DP vs. Non-DP was caudate nucleus 1.67 vs. 0.0, putamen 2.20 vs. 1.05, globus pallidus 1.2 vs. 0.65, thalamus 2.00 vs. 0.88 in the epileptic hemisphere. Conclusions: Caudate nucleus as well as putamen appeared to be important for producing ictal dystonia during TLE seizures. The greater intensity of ictal hyperperfusion in putamen, caudate nucleus and thalamus seems to be related to ictal dystonia.OAIID:oai:osos.snu.ac.kr:snu2003-01/102/2014017262/5SEQ:5PERF_CD:SNU2003-01EVAL_ITEM_CD:102USER_ID:2014017262ADJUST_YN:NEMP_ID:A079623DEPT_CD:801CITE_RATE:0DEPT_NM:의학과SCOPUS_YN:NCONFIRM:

Gelastic seizures involving the right parietal lobe

Gelastic seizures have been described in various epilepsies arising from the temporal or frontal lobes, although the most commonly encountered form is related to the presence of an hypothalamic hamartoma. We report a patient with gelastic seizures involving the right parietal lobe. Our patient, a 32-year-old man, underwent video-EEG monitoring, interictal and ictal brain SPECTs during gelastic seizures. Subtraction ictal SPECT co-registered to MRI (SISCOM), was performed to localize any ictal hyperperfusion during these gelastic seizures. The seizures consisted of brief staring followed by smiling and laughing. Electroencephalography during the gelastic seizures showed rhythmic sharp waves in the right parietal lobe. SISCOM showed ictal hyperperfusion in the right parietal lobe and medial portions of right cerebellum. Our findings suggest that the right parietal lobe may actively participate in the particular epileptogenic network generating gelastic seizures

Antiepileptic effects of low-frequency repetitive transcranial magnetic stimulation by different stimulation durations and locations

Objective: To evaluate the antiepileptic effect of low-frequency rTMS (repetitive transcranial magnetic stimulation) in the patients with intractable epilepsy. Methods: We enrolled 35 patients with localization-related epilepsy who had experienced at least one complex partial seizure or a secondarily generalized seizure per week on a constant antiepileptic drug regimen over an 8-week period. rTMS was administered using a Rapid 2 magnetic stimulator with an air-cooled coil at 0.5 Hz for 5 consecutive days at 100% of rMT (resting motor threshold). Patients were divided into a focal stimulation group with a localized epileptic focus, or a non-focal stimulation group with a non-localized or multifocal epileptic focus. These two groups were then randomly subdivided into four subgroups depending on the total number of stimulations administered, i.e., 3000 pulse and 1500 pulse subgroups. Weekly seizure frequencies were determined for 8 weeks before and after rTMS. To compare the number of interictal spikes before and after rTMS, EEG was recorded twice before (1st day) and after rTMS (5th day). Results: Mean weekly seizure frequency was non-significantly decreased after rTMS (8.4 → 6.8/week, -13.9%). Longer stimulation subgroups (3000 pulses, -23.0%) tended to have fewer seizures than shorter stimulation subgroups (1500 pulses, -3.0%), without statistical significance. TMS stimulation site and structural brain lesions did not influence seizure outcome. However, interictal spikes significantly decreased (-54.9%, P = 0.012) after rTMS and they totally disappeared in 6 patients (17.1%, 6/35). Conclusions: Low-frequency rTMS reduced interictal spikes, but its effect on seizure outcome was not significant. Focal stimulation for a longer duration tended to further reduce seizure frequency. Significance: These findings may help clinicians to further investigate the therapeutic potential of the rTMS for patients with intractable epilepsy. © 2006 International Federation of Clinical Neurophysiology

CBF changes in drug naive juvenile myoclonic epilepsy patients

Purpose: The role of thalamus and brainstem in generalized epilepsy has been suggested in previous studies. The aim of the present study was to assess regional cerebral blood flow (rCBF) abnormality in juvenile myoclonic epilepsy (JME) patients. Methods: 99mTc-ethylcysteinate dimer brain single photon emission computed tomography (SPECT) was performed in 19 drug naive JME patients and 25 normal controls with the similar age and gender distribution. Differences of rCBF between a JME group and a normal control group were examined by the statistical parametric mapping of brain SPECT images using independent t test. The regression analyses in SPM were also performed between rCBF and the age of seizure onset or the disease duration in JME group. Results: Compared to normal controls, the JME group showed a significant rCBF reduction in bilateral thalami, red nucleus, midbrain, pons, left hippocampus, and in the cerebelli (FDR corrected p &amp;amp;amp;lt; 0.01) whereas rCBF increase in the left superior frontal gyrus (uncorrected p &amp;amp;amp;lt; 0.001 but FDR corrected p &amp;amp;amp;gt; 0.05). Disease duration was negatively correlated with rCBF in bilateral frontal cortices, caudate nuclei, brainstem and cerebellar tonsils. Conclusions: Our results suggest that abnormal neural networks in the thalamus, hippocampus, brainstem and cerebellum are associated with JME. © 2007 Steinkopff-Verlag

Cerebral perfusion changes during cataplexy in narcolepsy patients

To localize cerebral perfusion differences during cataplexy, brain SPECT subtraction was performed between cataplexy and baseline awake period or REM sleep in patients with narcolepsy. During cataplexy, subtracted SPECT showed hyperperfusion in right amygdala, bilateral cingulate gyri, basal ganglia, thalami, premotor cortices, sensorimotor cortices, right insula, and brainstem, and hypoperfusion in prefrontal cortex and occipital lobe. This result suggests that cataplexy is produced by the activation of amygdalo-cortico-basal ganglia-brainstem circuit. Copyright © 2006 by AAN Enterprises, Inc

Effect of lamotrigine on cerebral blood flow in patients with idiopathic generalised epilepsy

Purpose: The purpose of this study was to investigate the effects of the new anti-epileptic drug, lamotrigine, on cerebral blood flow by performing 99mTc-ethylcysteinate dimer (ECD) single-photon emission computed tomography (SPECT) before and after medication in patients with drug-naive idiopathic generalised epilepsy. Methods: Interictal 99mTc-ECD brain SPECT was performed before drug treatment started and then repeated after lamotrigine medication for 4-5 months in 30 patients with generalised epilepsy (M/F=14/16, 19.3±3.4 years). Seizure types were generalised tonic-clonic seizure in 23 patients and myoclonic seizures in seven. The mean lamotrigine dose used was 214.1±29.1 mg/day. For SPM analysis, all SPECT images were spatially normalised to the standard SPECT template and then smoothed using a 12-mm full-width at half-maximum Gaussian kernel. The paired t test was used to compare pre- and post-lamotrigine SPECT images. Results: SPM analysis of pre- and post-lamotrigine brain SPECT images showed decreased perfusion in bilateral dorsomedial nuclei of thalami, bilateral uncus, right amygdala, left subcallosal gyrus, right superior and inferior frontal gyri, right precentral gyrus, bilateral superior and inferior temporal gyri and brainstem (pons, medulla) after lamotrigine medication at a false discovery rate-corrected p&amp;amp;amp;lt;0.05. No brain region showed increased perfusion after lamotrigine administration. Conclusion: Our study demonstrates for the first time the effect of lamotrigine on interictal cerebral perfusion in drug-naive idiopathic generalised epilepsy patients. In summary, lamotrigine medication was found to reduce perfusion in cortico-thalamo-limbic areas, the orbitofrontal cortex, and brainstem. © Springer-Verlag 2006

Episodic diencephalic hypoperfusion in Kleine-Levin syndrome

A 22 year-old woman suffered from recurrent episodes of hypersomnia, apathy, and hyperphagia. The symptoms occurred 3 to 4 times per year, and each attack lasted 2 to 3 weeks. 99mTc-ethylcysteinate dimer brain single photon emission computed tomography (SPECT) was performed during symptomatic and asymptomatic periods. To localize brain regions with perfusion changes during symptomatic period, asymptomatic SPECT was subtracted from symptomatic SPECT. The subtracted SPECT showed significant hypoperfusion in the left hypothalamus, bilateral thalami, basal ganglia, bilateral medial and dorsolateral frontal regions, and left temporal lobe during the symptomatic period. These cerebral hypoperfusion areas support the diencephalic hypothesis and clinical symptoms of Kleine-Levin syndrome

SIMPLE PARTIAL STATUS EPILEPTICUS LOCLIZED BY SPECT SUBTRACTION IN CHRONIC CEREBRAL PARAGONIMIASIS

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